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You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + + + + +Title: COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 + +Author: Alexander von Humboldt + +Release Date: January 3, 2005 [eBook #14565] + +Language: English + +Character set encoding: UTF-8 + + +***START OF THE PROJECT GUTENBERG EBOOK COSMOS: A SKETCH OF THE PHYSICAL +DESCRIPTION OF THE UNIVERSE, VOL. 1*** + + +This eBook was prepared by Amy Zelmer + + + +This material taken from pages i-ii, iv and v, and 3-12 + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p i +COSMOS + +VOLUME I + +[p ii is blank] + +[p iii - not copied; pertains to reprint series] + +p iv [portrait] + +p v + +COSMOS + +A SKETCH +OR +A PHYSICAL DESCRIPTION OF THE UNIVERSE + +BY +ALEXANDER VON HUMBOLDT + +TRANSLATED FROM THE GERMAN +BY E. C. OTTE + +Naturae vero rerum vis atque majestas in omnibus momentis fides caret, si +quis modo partes ejus ac non totam complectatur animo. -- Plin., 'Hist. +Nat.', lib. vii, c. 1. + +VOLUME I + +WITH AN INTRODUCTION +BY NICOLAAS A. RUPKE + +THE JOHNS HOPKINS UNIVERSITY PRESS +Baltimore and London + +[page vi and Introduction to the 1997 edition not copied] + +p 1 +COSMOS + +VOLUME I + + +[p 2 is blank] + +p 3 +TRANSLATOR'S PREFACE. +----------------------- + +I CAN not more appropriately introduce the Cosmos than by presenting a brief +sketch of the life of its illustrious author.* While the name of Alexander +von Humboldt is familiar to every one, few, perhaps, are aware of the +peculiar circumstances of his scientific career and of the extent of his +labors in almost every department of physical knowledge. He was born on the +14th of September, 1769, and is, therefore, now in his 80th year. After +going through the ordinary course of education at Gottingen, and having made +a rapid tour through Holland, England, and France, he became a pupil of +Werner at the mining school of Freyburg, and in his 21st year published an +"Essay on the Basalts of the Rhine." Though he soon became officially +connected with the mining corps, he was enabled to continue his excursions +in foreign countries, for, during the six or seven years succeeding the +publication of his first essay, he seems to have visited Austria, +Switzerland, Italy, and France. His attention to mining did not, however, +prevent him from devoting his attention to other scientific pursuits, among +which botany and the then recent discovery of galvanism may be especially +noticed. Botany, indeed, we know from his own authority, occupied him +almost exclusively for some years; but even at this time he was practicing +the use of those astronomical and physical instruments which he afterward +turned to so singularly excellent an account. + + +[footnote] *For the following remarks I am mainly indebted to the articles +on the Cosmos in the two leading Quarterly Reviews. + +The political disturbances of the civilized world at the close +p 4 +of the last century prevented our author from carrying out various plans of +foreign travel which he had contemplated, and detained him an unwilling +prisoner in Europe. In the year 1799 he went to Spain, with the hope of +entering Africa from Cadiz, but the unexpected patronage which he received +at the court of Madrid led to a great alteration in his plans, and decided +him to proceed directly to the Spanish possessions in America, "and there +gratify the longings for foreign adventure, and the scenery of the tropics, +which had haunted him from boyhood, but had all along been turned in the +diametrically opposite direction of Asia." After encountering various risks +of capture, he succeeded in reaching America, and from 1799 to 1804 +prosecuted there extensive researches in the physical geography of the New +World, which has indelibly stamped his name in the undying records of +science. + +Excepting an excursion to Naples with Gay-Lussac and Von Buch in 1805 (the +year after his return from America), the succeeding twenty years of his life +were spent in Paris, and were almost exclusively employed in editing the +results of his American journey. In order to bring these results before the +world in a manner worthy of their importance, he commenced a series of +gigantic publications in almost every branch of science on which he had +instituted observations. In 1817, after twelve years of incessant toil, +four fifths were completed, and an ordinary copy of the part then in print +cost considerably more than one hundred pounds sterling. Since that time +the publication has gone on more slowly, and even now after the lapse of +nearly half a century, it remains, and probably ever will remain, incomplete. + +In the year 1828, when the greatest portion of his literary labor had been +accomplished, he undertook a scientific journey to Siberia, under the +special protection of the Russian government. In this journey -- a journey +for which he had prepared himself by a course of study unparalleled in the +history of travel -- he was accompanied by two companions hardly less +distinguished than himself, Ehrenberg and Gustav Rose, and +p 5 +the results obtained during their expedition are recorded by our author in +his 'Fragments Asiatiques', and in his 'Asie Centrale', and by Rose in his +'Reise nach dem Oural'. If the 'Asie Centrale' had been his only work, +constituting, as it does, an epitome of all the knowledge acquired by +himself and by former travelers on the physical geography of Northern and +Central Asia, that work alone would have sufficed to form a reputation of +the highest order. + +I proceed to offer a few remarks on the work of which I now present a new +translation to the English public, a work intended by its author "to embrace +a summary of physical knowledge, as connected with a delineation of the +material universe." + +The idea of such a physical description of the universe had, it appears, +been present to his mind from a very early epoch. It was a work which he +felt he must accomplish, and he devoted almost a lifetime to the +accumulation of materials for it. For almost half a century it had occupied +his thoughts; and at length, in the evening of life, he felt himself rich +enough in the accumulation of thought, travel, reading, and experimental +research, to reduce into form and reality the undefined vision that has so +long floated before him. The work, when completed, will form three volumes. + The 'first' volume comprises a sketch of all that is at present known of +the physical phenomena of the universe; the 'second' comprehends two +distinct parts, the first of which treats of the incitements to the study of +nature, afforded in descriptive poetry, landscape painting, and the +cultivation of exotic plants; while the second and larger part enters into +the consideration of the different epochs in the progress of discovery and +of the corresponding stages of advance in human civilization. The 'third' +volume, the publication of which, as M. Humboldt himself informs me in a +letter addressed to my learned friend and publisher, Mr. H. G. Bohn, "has +been somewhat delayed, owing to the present state of public affairs, will +comprise the special and scientific development of the great Picture of +Nature +p 6 +Each of the three parts of the 'Cosmos' is therefore, to a certain extent, +distinct in its object, and may be considered complete in itself. We can +not better terminate this brief notice than in the words of one of the most +eminent philosophers of our own country, that, "should the conclusion +correspond (as we doubt not) with these beginnings, a work will have been +accomplished every way worthy of the author's fame, and a crowning laurel +added to that wreath with which Europe will always delight to surround the +name of Alexander von Humboldt." + +In venturing to appear before the English public as the interpreter of "the +great work of our age,"* I have been encouraged by the assistance of many +kind literary and scientific friends, and I gladly avail myself of this +opportunity of expressing my deep obligations to Mr. Brooke, Dr. Day, +Professor Edward Forbes, Mr. Hind, Mr. Glaisher, Dr. Percy, and Mr. Ronalds, +for the valuable aid they have afforded me. + + +[footnote] *The expression applied to the Cosmos by the learned Bunsen, in +his late Report on Ethnology, in the 'Report of the British Association for' +1847, p. 265. + + +It would be scarcely right to conclude these remarks without a reference to +the translations that have preceded mine. The translation executed by Mrs. +Sabine is singularly accurate and elegant. The other translation is +remarkable for the opposite qualities, and may therefore be passed over in +silence. The present volumes differ from those of Mrs. Sabine in having all +the foreign measures converted into corresponding English terms, in being +published at considerably less than one third of the price, and in being a +translation of the entire work, for I have not conceived myself justified in +omitting passages, sometimes amounting to pages, simply because they might +be deemed slightly obnoxious to our national prejudices. + + +p 7 +AUTHOR'S PREFACE. +------------------- + +In the late evening of an active life I offer to the German public a work, +whose undefined image has floated before my mind for almost half a century. +I have frequently looked upon its completion as impracticable, but as often +as I have been disposed to relinquish the undertaking, I have again -- +although perhaps imprudently -- resumed the task. This work I now present +to my contemporaries with a diffidence inspired by a just mistrust of my own +powers, while I would willingly forget that writings long expected are +usually received with less indulgence. + +Although the outward relations of life, and an irresistible impulse toward +knowledge of various kinds, have led me to occupy myself for many years -- +and apparently exclusively -- with separate branches of science, as, for +instance, with descriptive botany, geognosy, chemistry, astronomical +determinations of position, and terrestrial magnetism, in order that I might +the better prepare myself for the extensive travels in which I was desirous +of engaging, the actual object of my studies has nevertheless been of a +higher character. The principal impulse by which I was directed was the +earnest endeavor to comprehend the phenomena of physical objects in their +general connection, and to represent nature as one great whole, moved and +animated by internal forces. My intercourse with highly-gifted men early +led me to discover that, without an earnest striving to attain to a +knowledge of special branches of study, all attempts to give a grand and +general view of the universe would be nothing more than a vain illusion. +These special departments in the great domain of natural +p 8 +science are, moreover, capable of being reciprocally fructified by means of +the appropriative forces by which they are endowed. Descriptive botany, no +longer confined to the narrow circle of the determination of genera and +species, leads the observer who traverses distant lands and lofty mountains +to the study of the geographical distribution of plants of the earth's +surface, according to distance from the equator and vertical elevation above +the sea. It is further necessary to investigate the laws which regulate the +differences of temperature and climate, and the meteorological processes of +the atmosphere, before we can hope to explain the involved causes of +vegetable distribution; and it is thus that the observer who earnestly +pursues the path of knowledge is led from one class of phenomena to another, +by means of the mutual dependence and connection existing between them. + +I have enjoyed an advantage which few scientific travelers have shared to an +equal extent, viz., that of having seen not only littoral districts, such as +are alone visited by the majority of those who take part in voyages of +circumnavigation, but also those portions of the interior of two vast +continents which present the most striking contrasts manifested in the +Alpine tropical landscapes of South America, and the dreary wastes of the +steppes in Northern Asia. Travels, undertaken in districts such as these, +could not fail to encourage the natural tendency of my mind toward a +generalization of views, and to encourage me to attempt, in a special work, +to treat of the knowledge which we at present possess, regarding the +sidereal and terrestrial phenomena of the Cosmos in their empirical +relations. The hitherto undefined idea of a physical geography has thus, by +an extended and perhaps too boldly imagined a plan, been comprehended under +the idea of a physical description of the universe, embracing all created +things in the regions of space and in the earth. + +The very abundance of the materials which are presented to the mind for +arrangement and definition, necessarily impart no inconsiderable +difficulties in the choice of the form under +p 9 +which such a work must be presented, if it would aspire to the honor of +being regarded as a literary composition. Descriptions of nature ought not +to be deficient in a tone of life-like truthfulness, while the mere +enumeration of a series of general results is productive of a no less +wearying impression than the elaborate accumulation of the individual data +of observation. I scarcely venture to hope that I have succeeded in +satisfying these various requirements of composition, or that I have myself +avoided the shoals and breakers which I have known how to indicate to +others. My faint hope of success rests upon the special indulgence which +the German public have bestowed upon a small work bearing the title of +'Ansichten der Natur', which I published soon after my return from Mexico. +This work treats, under general points of view, of separate branches of +physical geography (such as the forms of vegetation, grassy plains, and +deserts). The effect produced by this small volume has doubtlessly been +more powerfully manifested in the influence it has exercised on the +sensitive minds of the young, whose imaginative faculties are so strongly +manifested, than by means of any thing which it could itself impart. In the +work on the Cosmos on which I am now engaged, I have endeavored to show, as +in that entitled 'Ansichten der Natur', that a certain degree of scientific +completeness in the treatment of individual facts is not wholly incompatible +with a picturesque animation of style. +Since public lectures seemed to me to present an easy and efficient means of +testing the more or less successful manner of connecting together the +detached branches of any one science, I undertook, for many months +consecutively, first in the French language, at Paris, and afterward in my +own native German, at Berlin (almost simultaneously at two different places +of assembly), to deliver a course of lectures on the physical description of +the universe, according to my conception of the science. My lectures were +given extemporaneously, both in French and German, and without the aid of +written notes, nor have I, in any way, made use, in the present work, +p 10 +of those portions of my discourses which have been preserved by the industry +of certain attentive auditors. With the exception of the first forty pages, +the whole of the present work was written, for the first time, in the years +1843 and 1844. + +A character of unity, freshness, and animation must, I think, be derived +from an association with some definite epoch, where the object of the writer +is to delineate the present condition of knowledge and opinions. Since the +additions constantly made to the latter give rise to fundamental changes in +pre-existing views, my lectures and the Cosmos have nothing in common beyond +the succession in which the various facts are treated. The first portion of +my work contains introductory considerations regarding the diversity in the +degrees of enjoyment to be derived from nature, and the knowledge of the +laws by which the universe is governed; it also considers the limitation and +scientific mode of treating a physical description of the universe, and +gives a general picture of nature which contains a view of all the phenomena +comprised in the Cosmos. + +This general picture of nature, which embraces within its wide scope the +remotest nebulous spots, and the revolving double stars in the regions of +space, no less than the telluric phenomena included under the department of +the geography of organic forms (such as plants, animals, and races of men), +comprises all that I deem most specially important with regard to the +connection existing between generalities and specialities, while it moreover +exemplifies, by the form and style of the composition, the mode of treatment +pursued in the selection of the results obtained from experimental +knowledge. The two succeeding volumes will contain a consideration of the +particular means of incitement toward the study of nature (consisting in +animated delineations, landscape painting, and the arrangement and +cultivation of exotic vegetable forms), of the history of the contemplation +of the universe, or the gradual development of the reciprocal action of +natural forces constituting one natural whole; and lastly, of the special +p 11 +branches of the several departments of science, whose mutual connection is +indicated in the beginning of the work. Wherever it has been possible to do +so, I have adduced the authorities from whence I derived my facts, with a +view of affording testimony both to the accuracy of my statements and to the +value of the observations to which reference was made. In those instances +where I have quoted from my own writings (the facts contained in which +being, from their very nature, scattered through different portions of my +works), I have always referred to the original editions, owing to the +importance of accuracy with regard to numerical relations, and to my own +distrust of the care and correctness of translators. In the few cases where +I have extracted short passages from the works of my friends, I have +indicated them by marks of quotation; and, in imitation of the practice of +the ancients, I have invariably preferred the repetition of the same words +to any arbitrary substitution of my own paraphrases. The much-contested +question of priority of claim to a first discovery, which it is so dangerous +to treat of in a work of this uncontroversial kind, has rarely been touched +upon. Where I have occasionally referred to classical antiquity, and to +that happy period of transition which has rendered the sixteenth and +seventeenth centuries so celebrated, owing to the great geographical +discoveries by which the age was characterized, I have been simply led to +adopt this mode of treatment, from the desire we experience from time to +time, when considering the general views of nature, to escape from the +circle of more strictly dogmatical modern opinions, and enter the free and +fanciful domain of earlier presentiments. + +It has frequently been regarded as a subject of discouraging consideration, +that while purely literary products of intellectual activity are rooted in +the depths of feeling, and interwoven with the creative force of +imagination, all works treating of empirical knowledge, and of the +connection of natural phenomena and physical laws, are subject to the most +marked modifications of form in the lapse of short periods of time, both +p 12 +by the improvement in the instruments used, and by the consequent expansion +of the field of view opened to rational observation, and that those +scientific works which have, to use a common expression, become 'antiquated' +by the acquisition of new funds of knowledge, are thus continually being +consigned to oblivion as unreadable. However discouraging such a prospect +must be, no one who is animated by a genuine love of nature, and by a sense +of the dignity attached to its study, can view with regret any thing which +promises future additions and a greater degree of perfection to general +knowledge. Many important branches of knowledge have been based upon a +solid foundation which will not easily be shaken, both as regards the +phenomena in the regions of space and on the earth; while there are other +portions of science in which general views will undoubtedly take the place +of merely special; where new forces will be discovered and new substances +will be made known, and where those which are now considered as simple will +be decomposed. I would, therefore, venture to hope that an attempt to +delineate nature in all its vivid animation and exalted grandeur, and to +trace the 'stable' amid the vacillating, ever-recurring alternation of +physical metamorphoses, will not be wholly disregarded even at a future age. +'Potsdam, Nov.', 1844. + +This material taken from pages 13-22 +NB - The page numbers will be properly aligned in Courier 12 font. + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p 13 + +CONTENTS OF VOL. I. +---------------------- + + Page +The Translator's Preface . . . . . . . . . . . . . . . . . . . . . .3 +The Author's Preface . . . . . . . . . . . . . . . . . . . . . . . .7 +Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 + +INTRODUCTION. +The Results of the Study of Physical Phenomena . . . . . . . . . . 23 +The different Epochs of the Contemplation of the external World . .24 +The different Degrees of Enjoyment presented by the Contemplation + of Nature . . . . . . . . . . . . . . . . . . . . . . . . . . 25 +Instances of this Species of Enjoyment . . . . . . . . . . . . . . 26 +Means by which it is induced . . . . . . . . . . . . . . . . . . . 26 +The Elevations and climatic Relations of many of the most + celebrated Mountains in the World, considered with + Reference to the Effect produced on the Mind of the + Observer . . . . . . . . . . . . . . . . . . . . . . . . . .27-33 +The Impressions awakened by the Aspect of tropical Regions . . . . 34 +The more accurate Knowledge of the Physical Forces of the + Universe, acquired by the Inhabitants of a small Section + of the temperate Zone . . . . . . . . . . . . . . . . . . . . .36 +The earliest Dawn of the Science of the Cosmos . . . . . . . . . . 36 +The Difficulties that opposed the Progress of Inquiry . . . . . . . 37 +Consideration of the Effect produced on the Mind by the + Observation of Nature, and the Fear entertained by some of + its injurious Influence . . . . . . . . . . . . . . . . . . . 40 +Illustrations of the Manner in which many recent Discoveries have + tended to Remove the groundless Fears entertained + regarding the Agency of certain Natural Phenomena . . . . . . 43 +The Amount of Scientific Knowledge required to enter on the + Consideration of Physical Phenomena . . . . . . . . . . . . . 47 +The Object held in View by the present Work . . . . . . . . . . . . 49 +The Nature of the Study of the Cosmos . . . . . . . . . . . . . . . 50 +The special Requirements of the present Age . . . . . . . . . . . . 53 +Limits and Method of Exposition of the Physical Description of the + Universe . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 +Considerations on the terms Physiology and Physics . . . . . . . . .58 +Physical Geography . . . . . . . . . . . . . . . . . . . . . . . . 59 +Celestial Phenomena . . . . . . . . . . . . . . . . . . . . . . . . 63 +The Natural Philosophy of the Ancients directed more to Celestial + than to Terrestrial Phenomena . . . . . . . . . . . . . . . . .65 +The able Treatises of Varenius and Carl Ritter . . . . . . . . .66, 67 +Signification of the Word Cosmos . . . . . . . . . . . . . . . . 68-70 +The Domain embraced by Cosmography . . . . . . . . . . . . . . . . 71 +Empiricism and Experiments . . . . . . . . . . . . . . . . . . . . 74 +The Process of Reason and Induction . . . . . . . . . . . . . . . .77 +p 14 +GENERAL REVIEW OF NATURAL PHENOMENA. +Connection between the Material and the Ideal World . . . . . . . . 80 +Delineation of Nature . . . . . . . . . . . . . . . . . . . . . . . 82 +Celestial Phenomena . . . . . . . . . . . . . . . . . . . . . . . . 83 +Sidereal Systems . . . . . . . . . . . . . . . . . . . . . . . . . 89 +Planetary Systems . . . . . . . . . . . . . . . . . . . . . . . . .90 +Comets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 +Aerolites . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111 +Zodiacal Light . . . . . . . . . . . . . . . . . . . . . . . . . . 137 +Translatory Motion of the Solar System . . . . . . . . . . . . . . 145 +The Milky Way . . . . . . . . . . . . . . . . . . . . . . . . . . .150 +Starless Openings . . . . . . . . . . . . . . . . . . . . . . . 152 +Terrestrial Phenomena . . . . . . . . . . . . . . . . . . . . . . .154 +Geographical Distribution . . . . . . . . . . . . . . . . . . . . .161 +Figure of the Earth . . . . . . . . . . . . . . . . . . . . . . . .163 +Density of the Earth . . . . . . . . . . . . . . . . . . . . . . . 169 +Internal Heat of the Earth . . . . . . . . . . . . . . . . . . . . 172 +Mean Temperature of the Earth . . . . . . . . . . . . . . . . . . .175 +Terrestrial Magnetism . . . . . . . . . . . . . . . . . . . . . . 177 +Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183 +Aurora Borealis . . . . . . . . . . . . . . . . . . . .. . . . . .193 +Geognostic Phenomena . . . . . . . . . . . . . . . . . . . . . . . 202 +Earthquakes . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 +Gaseous Emanations . . . . . . . . . . . . . . . . . . . . . . . . 207 +Hot Springs . . . . . . . . . . . . . . . . . . . . . . . . . . . .221 +Salses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .224 +Volcanoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . .227 +Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .247 +Palaeontology . . . . . . . . . . . . . . . . . . . . . . . . . . .270 +Geognostic Periods . . . . . . . . . . . . . . . . . . . . . . . . 286 +Physical Geography . . . . . . . . . . . . . . . . . . . . . . . . 287 +Meteorology . . . . . . . . . . . . . . . . . . . . . . . . . . . .311 +Atmospheric Pressure . . . . . . . . . . . . . . . . . . . . . . . 315 +Climatology . . . . . . . . . . . . . . . . . . . . . . . . . . . .317 +The Snow-line . . . . . . . . . . . . . . . . . . . . . . . . . . .329 +Hygrometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332 +Atmospheric Electricity . . . . . . . . . . . . . . . . . . . . . .335 +Organic Life . . . . . . . . . . . . . . . . . . . . . . . . . . . 339 +Motion in Plants . . . . . . . . . . . . . . . . . . . . . . . . . 341 +Universality of Animal Life . . . . . . . . . . . . . . . . . . . .342 +Geography of Plants and Animals . . . . . . . . . . . . . . . . . .346 +Floras of different Countries . . . . . . . . . . . . . . . . . . .350 +Man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .352 +Races . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .353 +Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357 +Conclusion of the Subject . . . . . . . . . . . . . . . . . . . . .359 + + +p 15 +SUMMARY. +----------- + +Translator's Preface. +Author's Preface. + +Vol I. + +GENERAL SUMMARY OF THE CONTENTS. + +Introduction. -- Reflections on the different Degrees of Enjoyment presented +to us by the Aspect of Nature and the scientific Exposition of the Laws of +the Universe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +. . .Page 23-78 + +Insight into the connection of phenomena as the aim of all natural +investigation. Nature presents itself to meditative contemplation as a +unity in diversity. Differences in the grades of enjoyment yielded by +nature. Effect of contact with free nature; enjoyment derived from nature +independently of a knowledge of the action of natural forces, or of the +physiognomy and configuration of the surface, or of the character of +vegetation. Reminiscences of the woody valleys of the Cordilleras and of +the Peak of Teneriffe. Advantages of the mountainous region near the +equator, where the multiplicity of natural impressions attains its maximum +within the most circumscribed limits, and where it is permitted to man +simultaneously to behold all the stars of the firmament and all the forms of +vegetation -- p. 23-33. + +Tendency toward the investigation of the causes of physical phenomena. +Erroneous views of the character of natural forces arising from an imperfect +mode of observation or of induction. The crude accumulation of physical +dogmas transmitted from one country to another. Their diffusion among the +higher classes. +Scientific physics are associated with another and a deep-rooted system of +untried and misunderstood experimental positions. Investigation of natural +laws. Apprehension that nature may lose a portion of its secret charm by an +inquiry into the internal character of its forces, and that the enjoyment of +nature must necessarily be weakened by a study of its domain. Advantages of +general views which impart an exalted and solemn character to natural +science. The possibility of separating generalities from specialties. +Examples drawn from astronomy, recent optical discoveries, physical +geognosy, and the geography of plants. Practicability of the study of +physical cosmography -- p. 33-54. Misunderstood popular knowledge, +confounding cosmography with a mere encyclopedic enumeration of natural +sciences. Necessity for a simultaneous regard for all branches of natural +science. Influence of this study on national prosperity and the welfare of +nations; its more earnest and characteristic aim is an inner one, arising +from exalted mental activity. Mode of treatment with regard to the object +and presentation; reciprocal connection existing between thought and speech +-- p. 54-56. + +The notes to p. 28-33. Comparative hypsometrical data of the elevations of +the Dhawalagiri, Jawahir, Chimborazo, Aetna (according to the measurement of +Sir John Herschel), the Swiss Alps, etc. -- p. 28. Rarity +p 16 +of palms and ferns in the Himalaya Mountains -- p. 29. European vegetable +forms in the Indian Mountains -- p. 30. Northern and southern limits of +perpetual snow on the Himalaya; influence of the elevated plateau of Thibet +-- p. 30-33. Fishes of an earlier world -- p. 46. + +Limits and Method of Exposition of the Physical Description of the Universe +. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . +Page 56-78 + +Subjects embraced by the study of the Cosmos or of physical cosmography. +Separation of other kindred studies -- p. 56-62. The uranological portion +of the Cosmos is more simple than the telluric; the impossibility of +ascertaining the diversity of matter simplifies the study of the mechanism +of the heavens. Origin of the word 'Cosmos', its signification of adornment +and order of the universe. The 'existing' can not be absolutely separated +in our contemplation of nature from the 'future'. History of the world and +description of the world -- p. 26-73. +Attempts to embrace the multiplicity of the phenomena of the Cosmos in the +unity of thought and under the form of a purely rational combination. +Natural philosophy, which preceded all exact observation in antiquity, is a +natural, but not unfrequently ill-directed, effort of reason. Two forms of +abstraction rule in the whole mass of knowledge, viz.: the 'quantitative', +relative determinations according to number and magnitude, and +'qualitative', material characters. Means of submitting phenomena to +calculation. Atoms, mechanical methods of construction. Figurative +representations; mythical conception of imponderable matters, and the +peculiar vital forces in every organism. That which is attained by +observation and experiment (calling forth phenomena) leads, by analogy and +induction, to a knowledge of 'empirical laws'; their gradual simplification +and generalization. Arrangement of the facts discovered in accordance with +leading ideas. The treasure of empirical contemplation, collected through +ages, is in no danger of experiencing any hostile agency from philosophy -- +p. 73-78. + +[In the notes appended to p. 66-70 are considerations of the general and +comparative geography of Varenius. Philological investigation into the +meaning of the words [Greek word] and 'mundus'.] + +Delineation of Nature. General Review of Natural Phenomena. . . . . p. +79-359 + +Introduction -- p. 79-83. A descriptive delineation of the world embraces +the whole universe ([Greek words]) in the celestial and terrestrial spheres. + Form and course of the representation. It begins with the laws of +gravitation, and with the region of the remotest nebulous spots and double +stars, and then, gradually descending through the starry stratum to which +our solar system belongs, it contemplates this terrestrial spheroid, +surrounded by air and water, and finally, proceeds to the consideration of +the form of our planet, its temperature and magnetic tension, and the +fullness of organic vitality which is unfolded on its surface under the +action of light. Partial insight into the relative dependence existing +among all phenomena. Amid all the mobile and unstable elements in space, +'mean numerical values' are the ultimate aim of investigation, being the +expression of the physical laws, or forces of the Cosmos. The delineation +of the universe does not begin with the earth, from which a merely +subjective point of view might have led us to start, but rather with the +objects comprised in the regions of space. Distribution of matter, which is +partially conglomerated into rotating +p 17 +and circling heavenly bodies of very different density and magnitude, and +partly scattered as self-luminous vapor. Review of the separate portions of +the picture of nature, for the purpose of explaining the reciprocal +connection of all phenomena. + +I. Celestial Portion of the Cosmos . . . . . . . . . . . . . . . . .Page +83-154 + +II. Terrestrial Portion of the Cosmos . . . . . . . . . . . . . . . .p. +154-359 + +a. Form of the earth, its mean density, quantity of heat, electro-magnetic +activity, process of light -- p. 154-202. + +b. Vital activity of the earth toward its external surface. Reaction of +the interior of a planet on its crust and surface. Subterranean noise +without waves of concussion. Earthquakes dynamic phenomena -- p. 202-217. + +c. Material products which frequently accompany earthquakes. Gaseous and +aqueous springs. Salses and mud volcanoes. Upheavals of the soil by +elastic forces -- p. 217-228. + +d. Fire-emitting mountains. Craters of elevation. Distribution of +volcanoes on the earth -- p. 228-247. + +e. Volcanic forces form new kinds of rock, and metamorphose those already +existing. Geognostical classification of rocks into four groups. Phenomena +of contact. Fossiliferous strata; their vertical arrangement. The faunas +and floras of an earlier world. Distribution of masses of rock -- p. +247-384. + +f. Geognostical epochs, which are indicated by the mineralogical difference +of rocks, have determined the distribution of solids and fluids into +continents and seas. Individual configuration of solids into horizontal +expansion and vertical elevation. Relations of area. Articulation. +Probability of the continued elevation of the earth's crust in ridges -- p. +284-301. + +g. Liquid and aeriform envelopes of the solid surface of our planet. +Distribution of heat in both. The sea. The tides. Currents and their +effects -- p. 301-311. + +h. The atmosphere. Its chemical composition. Fluctuations in its density. + Law of the direction of the winds. Mean temperature. Enumeration of the +causes which tend to raise and lower the temperature. Continental and +insular climates. East and west coasts. Cause of the curvature of the +isothermal lines. Limits of perpetual snow. Quantity of vapor. +Electricity in the atmosphere. Forms of the clouds -- p. 311-339. + +i. Separation of inorganic terrestrial life from the geography of vital +organisms; the geography of vegetables and animals. Physical gradations of +the human race -- p. 339-359. + + +Special Analysis of the Delineation of Nature, including References to the +Subjects treated of in the Notes. + +I. Celestial Portion of the Cosmos . . . . . . . . . . . . . . . . . p. +83-154 + +The universe and all that it comprises -- multiform nebulous spots, +planetary vapor, and nebulous stars. The picturesque charm of a southern +sky -- note, p. 85. Conjectures on the position in space of the world. Our +stellar masses. A cosmical island. Gauging stars. Double stars revolving +round a common center. Distance of the star 61 Cygni -- p. 88 and note. +Our solar system more complicated than was conjectured at the close of the +last century. Primary planets with Neptune, Astrea, Hebe, Iris, and Flora, +now constitute 16; secondary planets 18; myriad of comets of which many of +the inner ones are inclosed +p 18 +in the orbits of the planets; a rotating ring (the zodiacal light) and +meteoric stones, probably to be regarded as small cosmical bodies. The +telescopic planets, Vesta, Juno, Ceres, Pallas, Astrea, Hebe, Iris and +Flora, with their frequently intersecting, strongly inclined, and more +eccentric orbits, constitute a central group of separation between the inner +planetary group (Mercury, Venus, the Earth, and Mars) and the outer group +(Jupiter, Saturn, Uranus, and Neptune). Contrasts of these planetary +groups. Relations of distance from one central body. Differences of +absolute magnitude, density, period of revolution, eccentricity, and +inclination of the orbits. The so-called law of the distances of the +planets from their central sun. The planets which have the largest number +of moons -- p. 96 and note. Relations in space, both absolute and relative, +of the secondary planets. Largest and smallest of the moons. Greatest +approximation to a primary planet. Retrogressive movement of the moons of +Uranus. Libration of the Earth's satellite -- p. 98 and note. Comets; the +nucleus and tail; various forms and directions of the emanations in conoidal +envelopes, with more or less dense walls. Several tails inclined toward the +sun; change of form of fixed stars by the nuclei of comets. Eccentricity of +their orbits and periods of revolution. Greatest distance and greatest +approximation of comets. Passage through the system of Jupiter's +satellites. Comets of short periods of revolution, more correctly termed +inner comets (Encke, Biela, Faye) -- p. 107 and note. Revolving aerolites +(meteoric stones, fire-balls, falling stars). Their planetary velocity, +magnitude, form, observed height. Periodic return in streams; the November +stream and the stream of St. Lawrence. Chemical composition of meteoric +asteroids -- p. 130 and notes. Ring of zodiacal light. Limitation of the +present solar atmosphere -- p. 141 and note. Translatory motion of the +whole solar system -- p. 145-149 and note. The existence of the law of +gravitation beyond our solar system. The milky way of stars and its +conjectured breaking up. Milky way of nebulous spots, at right angles with +that of the stars. Periods of revolutions of bi-colored double stars. +Canopy of stars; openings in the stellar stratum. Events in the universe; +the apparition of new stars. Propagation of light, the aspect of the starry +vault of the heavens conveys to the mind an idea of inequality of time -- p. +149-154 and notes. + +II. Terrestrial Portion of the Cosmos . . . . . . . . . . . . . . Page +154-359 + +a. Figure of the earth. Density, quantity of heat, electro-magnetic +tension, and terrestrial light -- p. 154-202 and note. Knowledge of the +compression and curvature of the earth's surface acquired by measurements of +degrees, pendulum oscillations, and certain inequalities in the moon's +orbit. Mean density of the earth. The earth's crust, and the depth to +which we are able to penetrate -- p. 159, 160, note. Threefold movement of +the heat of the earth; its thermic condition. Law of the increase of heat +with the increase of depth -- p. 160, 161 and note. Magnetism electricity +in motion. Periodical variation of terrestrial magnetism. Disturbance of +the regular course of the magnetic needle. Magnetic storms; extension of +their action. Manifestations of magnetic force on the earth's surface +presented under three classes of phenomena, namely, lines of equal force +(isodynamic), equal inclination (isoclinic), and equal deviation (isogonic). + Position of the magnetic pole. Its probable connection with the poles of +cold. Change of all the magnetic phenomena of the earth. Erection of +magnetic observatories +p 19 +since 1828; a far-extending net-work of magnetic stations -- p. 190 and +note. Development of light at the magnetic poles; terrestrial light as a +consequence of the electro-magnetic activity of our planet. Elevation of +polar light. Whether magnetic storms are accompanied by noise. Connection +of polar light (an electro-magnetic development of light) with the formation +of cirrus clouds. Other examples of the generation of terrestrial light -- +p. 202 and note. + +b. The vital activity of a planet manifested from within outward, the +principal source of geognostic phenomena. Connection between merely dynamic +concussions or the upheaval of whole portions of the earth's crust, +accompanied by the effusion of matter, and the generation of gaseous and +liquid fluids, of hot mud and fused earths, which solidify into rocks. +Volcanic action, in the most general conception of the idea, is the reaction +of the interior of a planet on its outer surface. Earthquakes. Extent of +the circles of commotion and their gradual increase. Whether there exists +any connection between the changes in terrestrial magnetism and the +processes of the atmosphere. Noises, subterranean thunder without any +perceptible concussion. The rocks which modify the propagation of the waves +of concussion. Upheavals; eruption of water, hot steam, mud mofettes, +smoke, and flame during an earthquake -- p. 202-218 and notes. + +c. Closer consideration of material products as a consequence of internal +planetary activity. There rise from the depths of the earth, through +fissures and cones of eruption, various gases, liquid fluids (pure or +acidulated), mud, and molten earths. Volcanoes are a species of +intermittent spring. Temperature of thermal springs; their constancy and +change. Depth of the foci -- p. 219-224 and notes. Salses, mud volcanoes. +While fire-emitting mountains, being sources of molten earths, produce +volcanic rocks, spring water forms, by precipitation, strata of limestone. +Continued generation of sedimentary rocks -- p. 228 and note. + +d. Diversity of volcanic elevations. Dome-like closed trachytic mountains. + Actual volcanoes which are formed from craters of elevations or among the +detritus of their original structure. Permanent connection of the interior +of our earth with the atmosphere. Relation to certain rocks. Influence of +the relations of height on the frequency of the eruptions. Heights of the +cone of cinders. Characteristics of those volcanoes which rise above the +snow-line. Columns of ashes and fire. Volcanic storm during the eruption. +Mineral composition of lavas -- p. 236 and notes. Distribution of volcanoes +on the earth's surface; central and linear volcanoes; insular and littoral +volcanoes. Distance of volcanoes from the sea-coast. Extinction of +volcanic forces -- p. 246 and notes. + +e. Relation of volcanoes to the character of rocks. Volcanic forces form +new rocks, and metamorphose the more ancient ones. The study of these +relations leads, by a double course, to the mineral portion of geognosy (the +study of the textures and of the position of the earth's strata), and to the +configuration of continents and insular groups elevated above the level of +the sea (the study of the geographical form and outlines of the different +parts of the earth. Classification of rocks according to the scale of the +phenomena of structure and metamorphosis, which are still passing before our +eyes. Rocks of eruption, sedimentary rocks, changed (metamorphosed) rocks, +conglomerates -- compound rocks are definite associations of +cryctognostically simple fossils. There are four phases in the formative +condition; rocks of eruption, +p 20 +endogenous (granite, sienite, porphyry, greenstone, hyperathene, rock, +euphotide, melaphyre, basalt, and phonolithe); sedimentary rocks (silurian +schist, coal measures, limestone, travertino, infusorial deposit); +metamorphosed rock, which contains also, together with the detritus mica +schist, and more ancient metamorphic masses. Aggregate and sandstone +formations. The phenomenon of contact explained by the artificial imitation +of minerals. Effects of pressure and the various rapidity of cooling. +Origin of granular or saccharoidal marble, silicification of schist into +ribbon jasper. Metamorphosis of calcareous marl into micaceous schist +through granite. Conversion of dolomite and granite into argillaceous +schist, by contact with basaltic and doleritic rocks. Filling up of the +veins from below. Processes of cementation in agglomerate structures. +Friction conglomerates -- p. 269 and note. Relative age of rocks, +chronometry of the earth's crust. Fossiliferous strata. Relative age of +organisms. Simplicity of the first vital forms. Dependence of +physiological gradations on the age of the formations. Geognostic horizon, +whose careful investigation may yield certain data regarding the identity or +the relative age of formations, the periodic recurrence of certain strata, +their parallelism, or their total suppression. Types of the sedimentary +structures considered in their most simple and general characters; silurian +and devonian formations (formerly known as rocks of transition); the lower +trias (mountain limestone, coal measures, together with 'todilegende' and +zechstein); the upper trias (butter sandstone, muschelkalk, and keuper); +Jura limestone (lias and oolite); freestone, lower and upper chalk, as the +last of the flotz strata, which begin with mountain limestone; tertiary +formations in three divisions, which are designated by granular limestone, +lignite, and south Apennine gravel -- p. 269-278. + +The faunas and floras of an earlier world, and their relations to existing +organisms. Colossal bones of antediluvian mammalia in the upper alluvium. +Vegetation of an earlier world; monuments of the history of its vegetation. +The points at which certain vegetable groups attain their maximum; cycadeae +in the keuper and lias, and coniferae in the butter sandstone. Lignite and +coal measures (amber-tree). Deposition of large masses of rock; doubts +regarding their origin -- p. 285 and note. + +f. The knowledge of geognostic epochs -- of the upheaval of mountain chains +and elevated plateaux, by which lands are both formed and destroyed, leads, +by an internal causal connection, to the distribution into solids and +fluids, and to the peculiarities in the natural configuration of the earth's +surface. Existing areal relations of the solid to the fluid differ +considerably from those presented by the maps of the physical portion of a +more ancient geography. Importance of the eruption of quartzose, porphyry +with reference to the then existing configuration of continental masses. +Individual conformation in horizontal extension (relations of articulation) +and in vertical elevation (hypsometrical views). Influence of the relations +of the area of land and sea on the temperature, direction of the winds, +abundance or scarcity of organic products, and on all meteorological +processes collectively. Direction of the major axes of continental masses. +Articulation and pyramidal termination toward the south. Series of +peninsulas. Valley-like formation of the Atlantic Ocean. Forms which +frequently recur -- p. 285-293 and notes. Ramifications and systems of +mountain chains, and the means of determining their relative ages. Attempts +to determine the centre of gravity of the volume of the lands upheaved above +the level +p 21 +of the sea. The elevation of continents is still progressing slowly, and is +being compensated for at some definite points by a perceptible sinking. All +geognostic phenomena indicate a periodical alteration of activity in the +interior of our planet. Probability of new elevations of ridges -- p. +293-301 and notes. + +g. The solid surface of the earth has two envelopes, one liquid, and the +other aeriform. Contrasts and analogies which these envelopes -- the sea +and the atmosphere -- present in their conditions of aggregation and +electricity, and in their relations of currents and temperature. Depths of +the ocean and of the atmosphere, the shoals of which constitute our +highlands and mountain chains. The degree of heat at the surface of the sea +in different latitudes and in the lower strata. Tendency of the sea to +maintain the temperature of the surface in the strata nearest to the +atmosphere, in consequence of the mobility of its particles and the +alteration in its density. Maximum of the density of salt water. Position +of the zones of the hottest water, and of those having the greatest saline +contents. Thermic influence of the lower polar current and the counter +currents in the straits of the sea -- p. 302-304 and notes. General level +of the sea, and permanent local disturbances of equilibrium; the periodic +disturbances manifested as tides. Oceanic currents; the equatorial or +rotation current, the Atlantic warm Gulf Stream, and the further impulse +which it receives; the cold Peruvian stream in the eastern portion of the +Pacific Ocean of the southern zone. Temperature of shoals. The universal +diffusion of life in the ocean. Influence of the small submarine sylvan +region at the bottom of beds of rooted algae, or on far-extending floating +layers of fucus -- p. 302-311 and notes. + +h. The gaseous envelope of our planet, the atmosphere. Chemical +composition of the atmosphere, its transparency, its polarization, pressure, +temperature, humidity, and electric tension. Relation of oxygen to +nitrogen; amount of carbonic acid; carbureted hydrogen; ammoniacal vapors. +Miamata. Regular (horary) changes in the pressure of the atmosphere. Mean +barometrical height at the level of the sea in different zones of the earth. + Isobarometrical curves. Barometrical windroses. Law of rotation of the +winds, and its importance with reference to the knowledge of many +meteorological processes. Land and sea winds, trade winds and monsoons -- +p. 311-317. Climatic distribution of heat in the atmosphere, as the effect +of the relative position of transparent and opaque masses (fluid and solid +superficial area), and of the hypsometrical configuration of continents. +Curvature of the isothermal lines in a horizontal and vertical direction, on +the earth's surface and in the superimposed strata of air. Convexity and +concavity of the isothermal lines. Mean heat of the year, seasons, months, +and days. Enumeration of the causes which produce disturbances in the form +of isothermal lines, i.e., their deviation from the position of the +geographical parallels. Isochimenal and isotheral lines are the lines of +equal winter and summer heat. Causes which raise or lower the temperature. +Radiation of the earth's surface, according to its inclination, color, +density, dryness, and chemical composition. The form of the cloud which +announces what is passing in the upper strata of the atmosphere is the image +of the strongly radiating ground projected on a hot summer sky. Contrast +between an insular or littoral climate, such as is experienced by all +deeply-articulated continents, and the climate of the interior of large +tracts of land. East and west coasts. Difference between the southern and +northern hemispheres. Thermal scales of +p 22 +cultivated plants, going down from the vanilla, cacoa, and musaceae, by +citrous and olives, and to vines yielding potable wines. The influence +which these scales exercise on the geographical distribution of cultivated +plants. The favorable ripening and the immaturity of fruits are essentially +influenced by the difference in the action of direct or scattered light in a +clear sky or in one overcast with mist. General summary of the causes which +yield a more genial climate to the greater portion of Europe considered as +the western peninsula of Asia -- p. 326. Determination of the changes in +the mean annual and summer temperature, which correspond to one degree of +geographical latitude. Equality of the mean temperature of a mountain +station, and of the polar distance of any point lying at the level of the +sea. Decrease of temperature with the decrease in elevation. Limits of +perpetual snow, and the fluctuations in these limits. Causes of disturbance +in the regularity of the phenomenon. Northern and southern chains of the +Himalaya; habitability of the elevated plateaux of Thibet -- p. 331. +Quantity of moisture in the atmosphere, according to the hours of the day, +the seasons of the year, degrees of latitude, and elevation. Greatest +dryness of the atmosphere observed in Northern Asia, between the river +districts of the Irtysch and the Obi. Dew, a consequence of radiation. +Quantity of rain -- p. 335. Electricity of the atmosphere, and disturbance +of the electric tension. Geographical distribution of storms. +Predettermination of atmospheric changes. The most important climatic +disturbances can not be traced, at the place of observation, to any local +cause, but are rather the consequence of some occurrence by which the +equilibrium in the atmospheric currents has been destroyed at some +considerable distance -- p. 335-339. + +i. Physical geography is not limited to elementary inorganic terrestrial +life, but, elevated to a higher point of view, it embraces the sphere of +organic life, and the numerous gradations of its typical development. +Animal and vegetable life. General diffusion of life in the sea and on the +land; microscopic vital forms discovered in the polar ice no less than in +the depths of the ocean within the tropics. Extension imparted to the +horizon of life by Ehrenberg's discoveries. Estimation of the mass (volume) +of animal and vegetable organisms -- p. 339-346. Geography of plants and +animals. Migrations of organisms in the ovum, or by means of organs capable +of spontaneous motion. Spheres of distribution depending on climatic +relations. Regions of vegetation, and classification of the genera of +animals. Isolated and social living plants and animals. The character of +flora and fauna is not determined so much by the predominance of separate +families, in certain parallels of latitude, as by the highly complicated +relations of the association of many families, and the relative numerical +value of their species. The forms of natural families which increase or +decrease from the equator to the poles. Investigations into the numerical +relation existing in different districts of the earth between each one of +the large families to the whole mass of phanerogamia -- p. 346-351. The +human race considered according to its physical gradations, and the +geographical distribution of its simultaneously occurring types. Races and +varieties. All races of men are forms of one single species. Unity of the +human race. Languages considered as the intellectual creations of mankind, +or as portions of the history of mental activity, manifest a character of +nationality, although certain historical occurrences have been the means of +diffusing idioms of the same family of languages among nations of wholly +different descent -- p. 351-359. + + + +In This material taken from pages 23 to 56 + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p 23 +INTRODUCTION. +---------------- + +REFLECTIONS ON THE DIFFERENT DEGREES OF ENJOYMENT PRESENTED TO US BY THE +ASPECT OF NATURE AND THE STUDY OF HER LAWS. + +In attempting, after a long absence from my native country, to develop the +physical phenomena of the globe, and the simultaneous action of the forces +that pervade the regions of space, I experience a two-fold cause of anxiety. + The subject before me is so inexhaustible and so varied, that I fear either +to fall into the superficiality of the encyclopedist, or to weary the mind +of my reader by aphorisms consisting of mere generalities clothed in dry and +dogmatical forms. Undue conciseness often checks the flow of expression, +while diffuseness is alike detrimental to a clear and precise exposition of +our ideas. Nature is a free domain, and the profound conceptions and +enjoyments she awakens within us can only be vividly delineated by thought +clothed in exalted forms of speech, worthy of bearing witness to the majesty +and greatness of the creation. + +In considering the study of physical phenomena, not merely in its bearings +on the material wants of life, but in its general influence on the +intellectual advancement of mankind, we find its noblest and most important +result to be a knowledge of the chain of connection, by which all natural +forces are linked together, and made mutually dependent upon each other; and +it is the perception of these relations that exalts our views and ennobles +our enjoyments. Such a result can, however, only be reaped as the fruit of +observation and intellect, combined with the spirit of the age, in which are +reflected all the varied phases of thought. He who can trace, through +by-gone times, the stream of our knowledge to its primitive source, will +learn from history how, for thousands of years, man has labored, amid the +ever-recurring changes of form, to recognize the invariability of natural +laws, and has thus, by the force of mind, gradually subdued a great portion +of the physical world to his dominion. In interrogating the history of the +past, we trace the mysterious course of ideas yielding the first glimmering +perception of the same image of +p 24 +a Cosmos, or harmoniously ordered whole, which, dimly shadowed forth to the +human mind in the primitive ages of the world, is now fully revealed to the +maturer intellect of mankind as the result of long and laborious observation. + +Each of these epochs of the contemplation of the external world -- the +earliest dawn of thought and the advanced stage of civilization -- has its +own source of enjoyment. In the former, this enjoyment, in accordance with +the simplicity of the primitive ages, flowed from an intuitive feeling of +the order that was proclaimed by the invariable and successive reappearance +of the heavenly bodies, and by the progressive development of organized +beings; while in the latter, this sense of enjoyment springs from a definite +knowledge of the phenomena of nature. When man began to interrogate nature, +and, not content with observing, learned to evoke phenomena under definite +conditions; when once he sought to collect and record facts, in order that +the fruit of his labors might aid investigation after his own brief +existence had passed away, the 'philosophy of Nature' cast aside the vague +and poetic garb in which she had been enveloped from her origin, and, having +assumed a severer aspect, she now weighs the value of observations, and +substitutes induction and reasoning for conjecture and assumption. The +dogmas of former ages survive now only in the superstitions of the people +and the prejudices of the ignorant, or are perpetuated in a few systems, +which, conscious of their weakness, shroud themselves in a vail of mystery. +We may also trace the same primitive intuitions in languages exuberant in +figurative expressions; and a few of the best chosen symbols engendered by +the happy inspiration of the earliest ages, having by degrees lost their +vagueness through a better mode of interpretation, are still preserved among +our scientific terms. + +Nature considered 'rationally', that is to say, submitted to the process of +thought, is a unity in diversity of phenomena; a harmony blending together +all created things, however dissimilar in form and attributes; one great +whole ([Greek words]) animated by the breath of life. The most important +result of a rational inquiry into nature is, therefore, to establish the +unity and harmony of this stupendous mass of force and matter, to determine +with impartial justice what is due to the discoveries of the past and to +those of the present, and to analyze the individual parts of natural +phenomena without succumbing beneath the weight of the whole. Thus, and +thus alone, is it permitted to man, while mindful of the high destiny +p 25 +of his race, to comprehend nature, to lift the vail that shrouds her +phenomena, and as it were, submit the results of observation to the test of +reason and of intellect. + +In reflecting upon the different degrees of enjoyment presented to us in the +contemplation of nature, we find that the first place must be assigned to a +sensation, which is wholly independent of an intimate acquaintance with the +physical phenomena presented to our view, or of the peculiar character of +the region surrounding us. In the uniform plain bounded only by a distant +horizon, where the lowly heather, the cistus, or waving grasses, deck the +soil; on the ocean shore, where the waves, softly rippling over the beach, +leave a track, green with the weeds of the sea; every where, the mind is +penetrated by the same sense of the grandeur and vast expanse of nature, +revealing to the soul, by a mysterious inspiration, the existence of laws +that regulate the forces of the universe. Mere communion with nature, mere +contact with the free air, exercise a soothing yet strengthening influence +on the wearied spirit, calm the storm of passion, and soften the heart when +shaken by sorrow to its inmost depths. Every where, in every region of the +globe, in every stage of intellectual culture, the same sources of enjoyment +are alike vouchsafed to man. The earnest and solemn thoughts awakened by a +communion with nature intuitively arise from a presentiment of the order and +harmony pervading the whole universe, and from the contrast we draw between +the narrow limits of our own existence and the image of infinity revealed on +every side, whether we look upward to the starry vault of heaven, scan the +far-stretching plain before us, or seek to trace the dim horizon across the +vast expanse of ocean. + +The contemplation of the individual characteristics of the landscape, and of +the conformation of the land in any definite region of the earth, gives rise +to a different source of enjoyment, awakening impressions that are more +vivid, better defined, and more congenial to certain phases of the mind, +than those of which we have already spoken. At one time the heart is +stirred by a sense of the grandeur of the face of nature, by the strife of +the elements, or, as in Northern Asia by the aspect of the dreary barrenness +of the far-stretching steppes; at another time, softer emotions are excited +by the contemplation of rich harvests wrested by the hand of man from the +wild fertility of nature, or by the sight of human habitations raised beside +some wild and foaming torrent. Here I regard less the degree of intensity +than the difference existing in the +p 26 +various sensations that derive their charm and permanence from the peculiar +character of the scene. + +If I might be allowed to abandon myself to the recollections of my own +distant travels, I would instance, among the most striking scenes of nature, +the calm sublimity of a tropical night, when the stars, not sparkling, as in +our northern skies, shed their soft and planetary light over the +gently-heaving ocean; or I would recall the deep valleys of the Cordilleras, +where the tall and slender palms pierce the leafy vail around them, and +waving on high their feathery and arrow-like branches for, as it were, "a +forest above a forest;"* or I would describe the summit of the Peak of +Teneriffe, when a horizontal layer of clouds, dazzling in whiteness, has +separated the cone of cinders from the plain below, and suddenly the +ascending current pierces the cloudy vail, so that the eye of the traveler +may range from the brink of the crater, along the vine-clad slopes of +Orotava, to the orange gardens and banana groves that skirt the shore. In +scenes like these, it is not the peaceful charm uniformly spread over the +face of nature that moves the heart, but rather the peculiar physiognomy and +conformation of the land, the features of the landscape, the ever varying +outline of the clouds, and their blending with the horizon of the sea, +whether it lies spread before us like a smooth and shining mirror, or is +dimly seen through the morning mist. All that the senses can but +imperfectly comprehend, all that is most awful in such romantic scenes of +nature, may become a source of enjoyment to man, by opening a wide field to +the creative powers of his imagination. Impressions change with the varying +movements of the mind, and we are led by a happy illusion to believe that we +receive from the external world that with which we have ourselves invested +it. + + +[footnote] *This expression is taken from a beautiful description of +tropical forest scenery in 'Paul and Virginia', by Bernardia de Saint Pierre. + + +When far from our native country, after a long voyage, we tread for the +first time the soil of a tropical land, we experience a certain feeling of +surprise and gratification in recognizing, in the rocks that surround us, +the same inclined schistose strata, and the same columnar basalt covered +with cellular amygdaloids, that we had left in Europe, and whose identity of +character, in latitudes so widely different, reminds us that the +solidification of the earth's crust is altogether independent of climatic +influences. But these rocky masses of schist and of basalt are covered with +vegetation of a character with which we are unacquainted, and of a +physiognomy wholly +p 27 +unknown to us; and it is then, amid the colossal and majestic forms of an +exotic flora, that we feel how wonderfully the flexibility of our nature +fits us to receive new impressions, linked together by a certain secret +analogy. We so readily perceive the affinity existing among all the forms +of organic life, that although the sight of a vegetation similar to that of +our native country might at first be most welcome to the eye, as the sweet +familiar sounds of our mother tongue are to the ear, we nevertheless, by +degrees, and almost imperceptibly, become familiarized with a new home and a +new climate. As a true citizen of the world, man every where habituates +himself to that which surrounds him; yet fearful, as it were, of breaking +the links of association that bind him to the home of his childhood, the +colonist applies to some few plants in a far-distant clime the names he had +been familiar with in his native land; and by the mysterious relations +existing among all types of organization, the forms of exotic vegetation +present themselves to his mind as nobler and more perfect developments of +those he had loved in earlier days. Thus do the spontaneous impressions of +the untutored mind lead, like the laborious deductions of cultivated +intellect, to the same intimate persuasion, that one sole and indissoluble +chain binds together all nature. + +It may seem a rash attempt to endeavor to separate, into its different +elements, the magic power exercised upon our minds by the physical world, +since the character of the landscape, and of every imposing scene in nature, +depends so materially upon the mutual relation of the ideas and sentiments +simultaneously excited in the mind of the observer. + +The powerful effect exercised by nature springs, as it were, from the +connection and unity of the impressions and emotions produced; and we can +only trace their different sources by analyzing the individuality of objects +and the diversity of forces. + +The richest and most varied elements for pursuing an analysis of this nature +present themselves to the eyes of the traveler in the scenery of Southern +Asia, in the Great Indian Archipelago, and more especially, too, in the New +Continent, where the summits of the lofty Cordilleras penetrate the confines +of the aerial ocean surrounding our globe, and where the same subterranean +forces that once raised these mountain chains still shake them to their +foundation and threaten their downfall. + +Graphic delineations of nature, arranged according to systematic views, are +not only suited to please the imagination, +p 28 +but may also, when properly considered, indicate the grades of the +impressions of which I have spoken, from the uniformity of the sea-shore, or +the barren steppes of Siberia, to the inexhaustible fertility of the torrid +zone. If we were even to picture to ourselves Mount Pilatus placed on the +Schreckhorn,* or the Schneekoppe of Silesia on Mont Blanc, we should +p 29 +not have attained to the height of that great Colossus of the Andes, the +Chimborazo, whose height is twice that of Mont Aetna; and we must pile the +Righi, or Mount Athos, on the summit of the Chimborazo, in order to form a +just estimate of the elevation of the Dhawalagiri, the highest point of the +Himalaya. + + +[footnote] *These comparisons are only approximative. The several +elevations above the level of the sea are, in accurate numbers, as follows: +The Schneekoppe or Riesenkoppe, in Silesia about 5270 feet, according to +Hallaschka. The Righi, 5902 feet, taking the height of the Lake of Lucerne +at 1426 feet, according to Eschman. (See 'Compte Rendu des Mesures +Trigonometriques en Suisse', 1840, p. 230.) Mount Athos, 6775 feet, +according to Captain Gaultier; Mount Pilatus, 7546 feet; Mount Aetna, 10,871 +feet, according to Captain Smyth; or 10,874 feet, according to the +barometrical measurement made by Sir John Herschel, and communicated to me +in writing in 1825, and 10,899 feet, according to angles of altitude taken +by Cacciatore at Palermo (calculated by assuming the terrestrial refraction +to be 0.076); the Schreckhorn, 12,383 feet; the Jungfrau, 13,720 feet, +according to Tralles; Mount Blanc, 15,775 feet, according to the different +measurements considered by Roger ('Bibl. Univ.', May, 1828, 0. 24-53), +15,733 feet, according to the measurements taken from Mount Columbier by +Carlini in 1821, and 15,748 feet, as measured by the Austrian engineers from +Trelod and the Glacier d'Ambin. + +[footnote continued] +The actual height of the Swiss mountains fluctuates, according to Eschman's +observations, as much as 25 English feet, owing to the varying thickness of +the stratum of snow that covers the summits. Chimborazo is, according to my +trigonometrical measurements, 21,421 feet (see Humboldt, 'Recueil d'Obs. +Astr.', tome i., p. 73), and Dhawalagiri, 28,074 feet. As there is a +difference of 445 feet between the determinations of Blake and Webb, the +elevation assigned to the Dhawalagiri (or white mountain, from the Sanscrit +'dhawala', white, and 'giri', mountain) can not be received with the same +confidence as that of the Jawahir, 25,749 feet, since the latter rests on a +complete trigonomietrical measurement (see Herbert and Hodgson in the +'Asiat. Res.', vol. xiv., p. 189, and Suppl. to 'Encycl. Brit.', vol. iv., +p. 643). I have shown elsewhere ('Ann. des Sciences Naturelles', Mars, +1825) that the height of the Dhawalagiri (28,074 feet) depends on several +elements that have not been ascertained with certainty, as azimuths and +latitudes (Humboldt, 'Asie Centrale', t. iii., p. 282). It has been +believed, but without foundation, that in the Tartaric chain, north of +Thibet, opposite to the chain of Kuen-lun, there are several snowy summits, +whose elevation is about 30,000 English feet (almost twice that of Mont +Blanc), or, at any rate, 29,000 feet (see Captain Alexander Gerard's and +John Gerard's 'Journey to the Boorendo Pass', 1840, vol. i., p. 143 and +311). Chimborazo is spoken of in the text only as 'one' of the highest +summits of the chain of the Andes; for in the year 1827, the learned and +highly-gifted traveler, Pentland, in his memorable expedition to Upper Peru +(Bolivia), measured the elevation of two mountains situated to the east of +Lake Titicaca, viz., the Sorata, 25,200 feet, and the Illimani, 24,000 feet, +both greatly exceeding the height of Chimborazo, which is only 21,421 feet, +and being nearly equal in elevation to the Jawahir, which is the highest +mountain in the Himalaya that has as yet been accurately measured. Thus +Mont Blanc is 5646 feet below Chimborazo; Chimborazo, 3779 feet below the +Sorata; the Sorata, 549 feet below the Jawahir, and probably about 2880 feet +below the Dhawalagiri. According to a new measurement of the Illimani, by +Pentland, in 1838, the elevation of this mountain is given at 23,868 feet, +varying only 133 feet from the measurement taken in 1827. The elevations +have been given in this note with minute exactness, as erroneous numbers +have been introduced into many maps and tables recently published, owing to +incorrect reductions of the measurements. +[In the preceding note, taken from those appended to the Introduction in the +French translation, rewritten by Humboldt himself, the measurements are +given in meters, but these have been converted into English feet, for the +greater convenience of the general reader.] -- 'Tr.' + + +But although the mountains of India greatly surpass the Cordilleras of South +America by their astonishing elevation (which, after being long contested, +has at last been confirmed by accurate measurements), they can not, from +their geographical position, present the same inexhaustible variety of +phenomena by which the latter are characterized. The impression produced by +the grander aspects of nature dies not depend exclusively on height. The +chain of the Himalaya is placed far beyond the limits of the torrid zone, +and scarcely is a solitary palm-tree to be found in the beautiful valleys of +Kumaoun and Garhwal.* + + +[Footnote] *The absence of palms and tree-ferns on the temperate slopes of +the Himalaya is shown in Don's 'Flora Nepalensis', 1825, and in the +remarkable series of lithographs of Wallich's 'Flora Indica', whose +catalogue contains the enormous number of 7683 Himalaya species, almost all +phanerogamic plants, which have as yet been but imperfectly classified. In +Nepaul (lat. 26 1/2 degrees to 27 1/4 degrees) there has hitherto been +observed only one species of palm, Chamaerops martiana, Wall. ('Plantae +Asiat.', lib. iii., p. 5,211), which is found at the height of 5250 English +feet above the level of the sea, in the shady valley of Bunipa. The +magnificent tree-fern, Alsophila brunoniana, Wall. (of which a stem 48 feet +long has been in the possession of the British Museum since 1831), does not +grow in Nepaul, but is found on the mountains of Silhet, to the northwest of +Calcutta, in lat. 24 degrees 50 minutes. The Nepaul fern, Paranema +cyathoides, Don, formerly known as Sphaeroptera barbata, Wall. ('Plantae +Asiat.', lib. i., p. 42, 48), is indeed, nearly related to Cyathea, a +species of which I have seen in the South American Missions of Caripe, +measuring 33 feet in height; this is not, however, properly speaking a tree. + + +On the southern slope of the ancient Paropamisus, in the latitudes of 28 +degrees and 34 degrees, nature no longer displays the same abundance of +tree-ferns and arborescent grasses, heliconias and orchideous plants, which +in tropical +p 30 +regions are to be found even on the highest plateaux of the mountains. On +the slope of the Himalaya, under the shade of the Deodora and the +broad-leaved oak, peculiar to these Indian Alps, the rocks of granite and of +mica schist are covered with vegetable forms almost similar to those which +characterize Europe and Northern Asia. The species are not identical, but +closely analogous in aspect and physiognomy, as, marsh parnassia, and the +prickly species of Ribes.* The chain of the Himalaya is also wanting in the +imposing phenomena of volcanoes, which in the Andes and in the Indian +Archipelago often reveal to the inhabitants, under the most terrific forms, +the existence of the forces pervading the interior of our planet. + + +[footnote] *Ribes nubicola, R. glaciale, R. grossularia. The species which +compose the vegetation of the Himalaya are four pines, notwithstanding the +assertion of the ancients regarding Eastern Asia (Strabo, lib. 11, p. 510, +Cas.), twenty-five oaks, four birches, two chestnuts, seven maples, twelve +willows, fourteen roses, three species of strawberry, seven species of +Alpine roses ('rhododendra'), one of which attains a height of 20 feet, and +many other northern genera. Large white apes, having black faces, inhabit +the wild chestnut-tree of Kashmir, which grows to a height of 100 feet, in +lat. 33 degrees (see Carl von Hugel's 'Kaschmir', 1840, 2d pt. 249). Among +the Coniferae, we find the Pinus deodwara, or deodara (in Sanscrit, +'dewa-daru', the timber of the gods), which is nearly allied to Pinus +cedrus. Near the limit of perpetual snow flourish the large and showy +flowers of the Gentiana venusta, G. Moorcroftiana, Swertia purpurescens, S. +speciosa, Parnassia armata, P. nubicola, Poenia Emode, Tulipa stellata; and +besides varieties of European genera peculiar to these Indian mountains, +true European species as Leontodon taraxacum, Prunella vulgaris, Galium +aparine, and Thlaspi arvense. The heath mentioned by Saunders, in Turner's +'Travels', and which had been confounded with Calluna vulgaris, is an +Andromeda, a fact of the greatest importance in the geography of Asiatic +plants. If I have made use, in this work, of the unphilosophical +expressions of European genera, 'European' special, 'growing wild in Asia', +etc., it has been in consequence of the old botanical language, which, +instead of the idea of a large dissemination, or, rather, of the coexistence +of organic productions, has dogmatically substituted the false hypothesis of +a migration, which, from predilection for Europe, is further assumed to have +been from west to east. + + +Moreover, on the southern declivity of the Himalaya, where the ascending +current deposits the exhalations rising from a vigorous Indian vegetation, +the region of perpetual snow begins at an elevation of 11,000 or 12,000 feet +above the level of the sea,* thus setting a limit to the development of +organic +p 31 +life in a zone that is nearly 3000 feet lower than that to which it attains +in the equinoctial region of the Cordilleras. + + +[footnote] *On the southern declivity of the Himalaya, the limit of +perpetual snow is 12,978 feet above the level of the sea; on the northern +declivity, or, rather, on the peaks which rise above the Thibet, or +Tartarian plateau, this limit is at 16,625 feet from 30 1/2 degrees to 32 +degrees of latitude, while at the equator, in the Andes of Quito, it is +15,790 feet. Such is the result I have deduced from the combination of +numerous data furnished by Webb, Gerard, Herbert, and Moorcroft. (See my +two memoirs on the mountains of India, in 1816 and 1820, in the 'Ann. de +Chimie et de Physique', t. iii., p. 303; t. xiv., p. 6, 22, 50.) The +greater elevation to which the limit of perpetual snow recedes on the +Tartarian declivity is owing to the radiation of heat from the neighboring +elevated plains, to the purity of the atmosphere, and to the infrequent +formation of snow in an air which is both very cold and very dry. +(Humboldt, 'Asie Centrale', t. iii., p. 281-326.) My opinion on the +difference of height of the snow-line on the two sides of the Himalaya has +the high authority of Colebrooke in its favor. He wrote to me in June, +1824, as follows: "I also find, from the data in my possession, that the +elevation of the line of perpetual snow is 13,000 feet. On the southern +declivity, and at latitude 31 degrees, Webb's measurements give me 13,500 +feet, consequently 500 feet more than the height deduced from Captain +Hodgson's observations. Gerard's measurements fully confirm your opinion +that the line of snow is higher on the northern than on the southern side." +It was not until the present year (1840) that we obtained the complete and +collected journal of the brothers Gerard, published under the supervision of +Mr. Lloyd. ('Narrative of a Journey from Cawnpoor to the Boorendo Pass, in +the Himalaya, by Captain Alexander Gerard and John Gerard, edited by George +Lloyd', vol. i., p. 292, 311, 320, 327 and 341.) Many interesting details +regarding some localities may be found in the narrative of 'A Visit to the +Shatool, for the Purpose of determining the Line of Perpetual Snow on the +southern face of the Himalaya, in August', 1822. Unfortunately, however, +these travelers always confound the elevation at which sporadic snow falls +with the maximum of the height that the snow-line attains on the Thibetian +plateau. Captain Gerard distinguishes between the summits that rise in the +middle of the plateau, where he states the elevation of the snow-line to be +between 18,000 and 19,000 feet, and the northern slopes of the chain of the +Himalaya, which border on the defile of the Sutledge, and can radiate but +little heat, owing to the deep ravines with which they are intersected. The +elevation of the village of Tangno is given at only 9300 feet, while that of +the plateau surrounding the sacred lake of Maqasa is 17,000 feet. Captain +Gerard finds the snow-line 500 feet lower on the northern slopes, where the +chain of the Himalaya is broken through, than toward the southern +declivities facing Hindostan, and he there estimates the line of perpetual +snow at 15,000 feet. The most striking differences are presented between +the vegetation on the Thibetian plateau and that characteristic of the +southern slopes of the Himalaya. On the latter the cultivation of grain is +arrested at 9974 feet and even there the corn has often to be cut when the +blades are still green. The extreme limit of forests of tall oaks and +deodars is 11,960 feet; that of dwarf birches, 12,983 feet. On the plains, +Captain Gerard found pastures up to the height of 17,000 feet; the cereals +will grow at 14,100 feet, or even at 18,540 feet; birches with tall stems at +14,100 feet, and copse or brush wood applicable for fuel is found at an +elevation of upward of 17,000 feet, that is to say, 1280 feet and above the +lower limits of the snow-line at the equator, in the province of Quito. It +is very desirable that the 'mean' elevation of the Thibetian plateau, which +I have estimated at only about 8200 feet between the Himalaya and the +Kuen-lun, and the difference in the height of the line of perpetual snow on +the southern and on the northern slopes of the Himalaya, should be again +investigated by travelers who are accustomed to judge of the general +conformation of the land. Hitherto simple calculations have too often been +confounded with actual measurements, and the elevations of isolated summits +with that of the surrounding plateau. (Compare Carl Zimmerman's excellent +Hypsometrical Remarks in his 'Geographischen Analyse der Karte von Inner +Asien', 1841, s. 98.) Lord draws attention to the difference presented by +the two faces of the Himalaya and those of the Alpine chain of Hindoo-Coosh, +with respect to the limits of the snow-line. "The latter chain," he says, +"has the table-land to the south, in consequence of which the snow-line is +higher on the southern side, contrary to what we find to be the case with +respect to the Himalaya, which is bounded on the south by sheltered plains, +as Hindoo-Coosh is on the north." It must, however, be admitted that the +hypsometrical data on which these statements are based require a critical +revision with regard to several of their details; but still they suffice to +establish the main fact, that the remarkable configuration of the land in +Central Asia affords man all that is essential to the maintenance of life, +as habitation, food, and fuel, at an elevation above the level of the sea +which in almost all other parts of the globe is covered with perpetual ice. +We must except the very dry districts of Bolivia, where snow is so rarely +met with, and where Pentland (in 1838) fixed the snow-line at 15,667 feet, +between 16 degrees and 17 3/4 degrees south latitude. The opinion that I +had advanced regarding the difference in the snow-line on the two faces of +the Himalaya has been most fully confirmed by the barometrical observations +of Victor Jacquemont, who fell an early sacrifice to his noble and unwearied +ardor. (See his 'Correspondance pendant son Voyage dans l'Inde', 1828 'a' +1832, liv. 23, p. 290, 296, 299.) "Perpetual snow," says Jacquemont, +"descends lower on the southern than on the northern slopes of the Himalaya, +and the limit constantly rises as we advance to the north of the chain +bordering on India. On the Kionbrong, about 18,317 feet in elevation, +according to Captain Gerard, I was still considerably below the limit of +perpetual snow which I believe to be 19,690 feet in this part of Hindostan." + (This estimate I consider much too high.) + +[Footnote continues] The same traveler says, "To whatever height we rise on +the southern declivity of the Himalaya, the climate retains the same +character, and the same division of the seasons as in the plains of India; +the summer solstice being every year marked by the same prevalence of rain +which continues to fall without intermission until the autumnal equinox. +But a new, a totally different climate begins at Kashmir, whose elevation I +estimate to be 5350 feet, nearly equal to that of the cities of Mexico and +Popayan" ('Correspond. de Jacquemont', t. ii., p. 58 et 74). The warm and +humid air of the sea, as Leopold von Buch well observes, is carried by the +monsoons across the plains of India to the skirts of the Himalaya which +arrest its course, and hinder it from diverging to the Thibetian districts +of Ladak and Lassa. Carl von Hugel estimates the elevation of the Valley of +Kashmir above the level of the sea at 5818 feet, and bases his observation +on the determination of the boiling point of water (see theil 11, s. 155, +and 'Journal of Geog. Soc.', vol. vi., p. 215). In this valley, where the +atmosphere is scarcely ever agitated by storms, and in 34 degrees 7 minutes +lat., snow is found, several feet in thickness, from December to March. + +p 32 +But the countries bordering on the equator possess another advantage, to +which sufficient attention has not hitherto been +p 33 +directed. This portion of the surface of the globe affords in the smallest +space the greatest possible variety of impressions from the contemplation of +nature. Among the colossal mountains of Cundinamarea, of Quito, and of +Peru, furrowed by deep ravines, man is enabled to contemplate alike all the +families of plants, and all the stars of the firmament. There, at a single +glance, the eye surveys majestic palms, humid forests of bambusa, and the +varied species of Musaceae, while above these forms of tropical vegetation +appear oaks, medlars, the sweet-brier, and umbelliferous plants, as in our +European homes. There as the traveler turns his eyes to the vault of +heaven, a single glance embraces the constellation of the Southern Cross, +the Magellanic clouds, and the guiding stars of the constellation of the +Bear, as they circle round the arctic pole. There the depths of the earth +and the vaults of heaven display all the richness of their forms and the +variety of their phenomena. There the different climates are ranged the one +above the other, stage by stage, like the vegetable zones, whose succession +they limit; and there the observer may readily trace the laws that regulate +the diminution of heat, as they stand indelibly inscribed on the rocky walls +and abrupt declivities of the Cordilleras. + +Not to weary the reader with the details of the phenomena which I long since +endeavored graphically to represent,* I will here limit myself to the +consideration of a few of the general results whose combination constitutes +the 'physical delineation of the torrid zone.' That which, in the vagueness +of our +p 34 +impressions, loses all distinctness of form, like some distant mountain +shrouded from view by a vail of mist, is clearly revealed by the light of +mind, which, by its scrutiny into the causes of phenomena, learns to resolve +and analyze their different elements, assigning to each its individual +character. Thus, in the sphere of natural investigation, as in poetry and +painting, the delineation of that which appeals most strongly to the +imagination, derives its collective interest from the vivid truthfulness +with which the individual features are portrayed. + + +[footnote] *See, generally my 'Essai sur la Geographie des Plantes, et le +Tableau physique des Regions Equinoxiales', 1807, p. 80-88. On the diurnal +and nocturnal variations of temperature, see Plate 9 of my 'Atlas Geogr. et +Phys. du Nouveau Continent'; and the Tables in my work, entitled 'De +distributione Geographica Plantarum, secundum coeli tempriem, et altitudinem +Montium', 1817, p. 90-116; the meteorological portion of my 'Asie Centrale', +t. iii., p. 212, 224; and, finally, the more recent and far more exact +exposition of the variations of temperature experienced in correspondence +with the increase of altitude on the chain of the Andes, given in +Boussingault's Memoir, 'Sur la profondeur a laquelle on trouve, sous les +Tropiques, la couche de Temperature Invariable.' (Ann. de Chimie et de +Physique, 1833, t. liii., p. 225-247.) This treatise contains the +elevations of 128 points, included between the level of the sea and the +declivity of the Antisana (17,900 feet), as well as the mean temperature of +the atmosphere, which varies with the height between 81 degrees and 35 +degrees F. + + +The regions of the torrid zone not only give rise to the most powerful +impressions by their organic richness and their abundant fertility, but they +likewise afford the inestimable advantage of revealing to man, by the +uniformity of the variations of the atmosphere and the development of vital +forces, and by the contrasts of climate and vegetation exhibited at the +different elevations, the invariability of the laws that regulate the course +of the heavenly bodies, reflected, as it were, in terrestrial phenomena. +Let us dwell, then, for a few moments, on the proofs of this regularity, +which is such that it may be submitted to numerical calculation and +computation. + +In the burning plains that rise but little above the level of the sea, reign +the families of the banana, the cycas, and the palm, of which the number of +species comprised in the flora of tropical regions has been so wonderfully +increased in the present day by the zeal of botanical travelers. To these +groups succeed, in the Alpine valleys, and the humid and shaded clefts on +the slopes of the Cordilleras, the tree-ferns, whose thick cylindrical +trunks and delicate lace-like foliage stand out in bold relief against the +azure of the sky, and the cinchona, from which we derive the febrifuge bark. + The medicinal strength of this bark is said to increase in proportion to +the degree of moisture imparted to the foliage of the tree by the light +mists which form the upper surface of the clouds resting over the plains. +Every where around, the confines of the forest are encircled by broad bands +of social plants, as the delicate aralia, the thibaudia, and the +myrtle-leaved Andromeda, while the Alpine rose, the magnificent befaria, +weaves a purple girdle round the spiry peaks. In the cold regions of the +Paramos, which is continually exposed to the fury of storms and winds, we +find that flowering shrubs and herbaceous plants, bearing large and +variegated blossoms, have given place to monocotyledons, whose slender +spikes constitute the sole covering of the soil. This is the zone of the +p 35 +grasses, one vast savannah extending over the immense mountain plateaux, and +reflecting a yellow, almost golden tinge, to the slopes of the Cordilleras, +on which graze the lama and the cattle domesticated by the European +colonist. Where the naked trachyte rock pierces the grassy turf, and +penetrates into those higher strata of air which are supposed to be less +charged with carbonic acid, we meet only with plants of an inferior +organization, as lichens, lecideas, and the brightly-colored, dust-like +lepraria, scattered around in circular patches. Islets of fresh-fallen +snow, varying in form and extent, arrest the last feeble traces of vegetable +development, and to these succeeds the region of perpetual snow, whose +elevation undergoes but little change, and may be easily determined. It is +but rarely that the elastic forces at work within the interior of our globe +have succeeded in breaking through the spiral domes, which, resplendent in +the brightness of eternal snow, crown the summits of the Cordilleras; and +even where these subterranean forces have opened a permanent communication +with the atmosphere, through circular craters or long fissures, they rarely +send forth currents of lava, but merely eject ignited scoriae, steam, +sulphureted hydrogen gas, and jets of carbonic acid. + +In the earliest stages of civilization, the grand and imposing spectacle +presented to the minds of the inhabitants of the tropics could only awaken +feelings of astonishment and awe. It might, perhaps, be supposed, as we +have already said, that the periodical return of the same phenomena, and the +uniform manner in which they arrange themselves in successive groups, would +have enabled man more readily to attain to a knowledge of the laws of +nature; but, as far as tradition and history guide us, we do not find that +any application was made of the advantages presented by these favored +regions. Recent researches have rendered it very doubtful whether the +primitive seat of Hindoo civilization -- one of the most remarkable phases +in the progress of mankind -- was actually within the tropics. Airyana +Vaedjo, the ancient cradle of the Zend, was situated to the northwest of the +upper Indus, and after the great religious schism, that is to say, after the +separation of the Iranians from the Brahminical institution, the language +that had previously been common to them and to the Hindoos assumed among the +latter people (together with the literature, habits, and conditions of +society) an individual form in the Magodha of Madhya Desa,* a district that +is bounded by the great chain +p 36 +of Himalaya and the smaller range of the Vindhya. + + +[footnote] *See, on the Madhjadeca, properly so called, Lassen's excellent +work, entitled 'Indische Alterthumskunde', bd. i., s. 92. The Chinese give +the name of Mo-kie-thi to the southern Bahar, situated to the south of the +Ganges (see 'Foe-Koue-Ki' by, 'Chy-Fa-Hian', 1836, p. 256). Djambu-dwipa is +the name given to the whole of India; but the words also indicate one of the +four Buddhist continents. + + +In less ancient times the Sanscrit language and civilization advanced toward +the southeast, penetrating further within the torrid zone, as my brother +Wilhelm von Humboldt has shown in his great work on the Kavi and other +languages of analogous structure.* + + +[Footnote] *'Ueber die Kawi Sprache auf der Insel Java, nebst einer +Einleitung uber die Verschiedenheit des menschlichen Sprachbaues und ihren +Ein fluss auf die geistige Entwickelung des Menschengrshlecht's' von Wilhelm +v. Humboldt, 1836, bd. i., s. 50519. + + +Notwithstanding the obstacles opposed in northern latitudes to the discovery +of the laws of nature, owing to the excessive complication of phenomena, and +the perpetual local variations and the distribution of organic forms, it is +to the inhabitants of a small section of the temperate zone that the rest of +mankind owe the earliest revelation of an intimate and rational acquaintance +with the forces governing the physical world. Moreover, it is from the same +zone (which is apparently more favorable to the progress of reason, the +softening of manners, and the security of public liberty) that the germs of +civilization have been carried to the regions of the tropics, as much by the +migratory movement of races as by the establishment of colonies, differing +widely in their institution from those of the Phoenicians or Greeks. + +In speaking of the influence exercised by the succession of phenomena on the +greater or lesser facility of recognizing the causes producing them, I have +touched upon that important stage of our communion with the external world, +when the enjoyment arising from a knowledge of the laws, and the mutual +connection of phenomena, associates itself with the charm of a simple +contemplation of nature. That which for a long time remains merely an +object of vague intuition, by degrees acquires the certainty of positive +truth; and man, as an immortal poet has said, in our own tongue -- Amid +ceaseless change seeks the unchanging pole.* + + +[Footnote] *This verse occurs in a poem of Schiller, entitled 'Der +Spaziergang' which first appeared in 1795, in the 'Horen.' + + +In order to trace to its primitive source the enjoyment derived from the +exercise of thought, it is sufficient to cast a rapid glance on the earliest +dawnings of the philosophy of nature, or of the ancient doctrine of the +'Cosmos.' We find even +p 37 +among the most savage nations (as my own travels enable me to attest) a +certain vague, terror-stricken sense of the all-powerful unity of natural +forces, and of the existence of an invisible, spiritual essence manifested +in these forces, whether in unfolding the flower and maturing the fruit of +the nutrient tree, in upheaving the soil of the forest, or in rending the +clouds with the might of the storm. We may here trace the revelation of a +bond of union, linking together the visible world and that higher spiritual +world which escapes the grasp of the senses. The two become unconsciously +blended together, developing in the mind of man, as a simple product of +ideal conception and independently of the aid of observation, the first germ +of a 'Philosophy of Nature.' + +Among nations least advanced in civilization, the imagination revels in +strange and fantastic creations, and, by its predilection for symbols, alike +influences ideas and language. Instead of examining, men are led to +conjecture, dogmatize, and interpret supposed facts that have never been +observed. The inner world of thought and of feeling does not reflect the +image of the external world in its primitive purity. That which in some +regions of the earth manifested itself as the rudiments of natural +philosophy, only to a small number of persons endowed with superior +intelligence, appears in other regions, and among entire races of men, to be +the result of mystic tendencies and instinctive intuitions. An intimate +communion with nature, and the vivid and deep emotions thus awakened, are +likewise the source from which have sprung the first impulses toward the +worship and deification of the destroying and preserving forces of the +universe. But by degrees, as man, after having passed through the different +gradations of intellectual development, arrives at the free enjoyment of the +regulating power of reflection, and learns by gradual progress, as it were, +to separate the world of ideas from that of sensations, he no longer rests +satisfied merely with a vague presentiment of the harmonious unity of +natural forces; thought begins to fulfill its noble mission; and +observation, aided by reason, endeavors to trace phenomena to the causes +from which they spring. + +The history of science teaches us the difficulties that have opposed the +progress of this active spirit of inquiry. Inaccurate and imperfect +observations have led, by false inductions, to the great number of physical +views that have been perpetuated as popular prejudices among all classes of +society. Thus by the side of a solid and scientific knowledge of natural +phenomena there has been preserved a system of the pretended +p 38 +results of observation, which is so much the more difficult to shake, as it +denies the validity of the facts by which it may be refuted. This +empiricism, the melancholy heritage transmitted to us from former times, +invariably contends for the truth of its axioms with the arrogance of a +narrow-minded spirit. Physical philosophy, on the other hand, when based +upon science, doubts because it seeks to investigate, distinguishes between +that which is certain and that which is merely probable, and strives +incessantly to perfect theory by extending the circle of observation. + +This assemblage of imperfect dogmas, bequeathed by one age to another -- +this physical philosophy, which is composed of popular prejudices -- is not +only injurious because it perpetuates error with the obstinacy engendered by +the evidence of ill-observed facts, but also because it hinders the mind +from attaining to higher views of nature. Instead of seeking to discover +the 'mean' or 'medium' point, around which oscillate, in apparent +independence of forces, all the phenomena of the external world, this system +delights in multiplying exceptions to the law, and seeks, amid phenomena and +in organic forms for something beyond the marvel of a regular succession, +and an internal and progressive development. Ever inclined to believe that +the order of nature is disturbed, it refuses to recognize in the present any +analogy with the past, and guided by its own varying hypotheses, seeks at +hazard, either in the interior of the globe or in the regions of space, for +the cause of these pretended perturbations. + +It is the special object of the present work to combat those errors which +derive their source from a vicious empiricism and from imperfect inductions. + The higher enjoyments yielded by the study of nature depend upon the +correctness and the depth of our views, and upon the extent of the subjects +that may be comprehended in a single glance. Increased mental cultivation +has given rise, in all classes of society, to an increased desire of +embellishing life by augmenting the mass of ideas, and by multiplying means +for their generalization; and this sentiment fully refutes the vague +accusations advanced against the age in which we live, showing that other +interests, besides the material wants of life, occupy the minds of men. + +It is almost with reluctance that I am about to speak of a sentiment, which +appears to arise from narrow-minded views, or from a certain weak and morbid +sentimentality -- I allude to the 'fear' entertained by some persons, that +nature may by degrees lose a portion of the charm and magic of her power, +p 39 +as we learn more and more how to unvail her secrets, comprehend the +mechanism of the movements of the heavenly bodies, and estimate numerically +the intensity of natural forces. It is true that, properly speaking, the +forces of nature can only exercise a magical power over us as long as their +action is shrouded in mystery and darkness, and does not admit of being +classed among the conditions with which experience has made us acquainted. +The effect of such a power is, therefore, to excite the imagination, but +that, assuredly, is not the faculty of mind we would evoke to preside over +the laborious and elaborate observations by which we strive to attain to a +knowledge of the greatness and excellence of the laws of the universe. + +The astronomer who, by the aid of the heliometer or a double-refracting +prism,* determines the diameter of planetary bodies; who measures patiently +year after year, the meridian altitude and the relative distances of stars, +or who seeks a telescopic comet in a group of nebulae, does not feel his +imagination more excited -- and this is the very guarantee of the precision +of his labors -- than the botanist who counts the divisions of the calyx, or +the number of stamens in a flower, or examines the connected or the separate +teeth of the peristoma surrounding the capsule of a moss. Yet the +multiplied angular measurements on the one hand, and the detail of organic +relations on the other, alike aid in preparing the way for the attainment of +higher views of the laws of the universe. + + +[Footnote] *Arago's ocular micrometer, a happy improvement upon Rochon's +prismatic or double-refraction micrometer. See M. Mathieu's note in +Delambre's 'Histoire de l'Astronomie au dix-huitieme Siecle', 1827. + + +We must not confound the disposition of mind in the observer at the time he +is pursuing his labors, with the ulterior greatness of the views resulting +from investigation and the exercise of thought. The physical philosopher +measures with admirable sagacity the waves of light of unequal length which +by interference mutually strengthen or destroy each other, even with respect +to their chemical actions; the astronomer, armed with powerful telescopes, +penetrates the regions of space, contemplates, on the extremest confines of +our solar system, the satellites of Uranus, or decomposes faintly sparkling +points into double stars differing in color. The botanist discovers the +constancy of the gyratory motion of the chara in the greater number of +vegetable cells, and recognizes in the genera and natural families of plants +the intimate relations or organic forms. The vault of heaven, studded with +nebulae +p 40 +and stars, and the rich vegetable mantle that covers the soil in the climate +of palms, can not surely fail to produce on the minds of these laborious +observers of nature an impression more imposing and more worthy of the +majesty of creation than on those who are unaccustomed to investigate the +great mutual relations of phenomena. I can not, therefore, agree with Burke +when he says, "it is our ignorance of natural things that causes all our +admiration and chiefly excites our passions." + +While the illusion of the senses would make the stars stationary in the +vault of heaven, Astronomy, by her aspiring labors, has assigned indefinite +bounds to space; and if she have set limits to the great nebula to which our +solar system belongs, it has only been to show us in those remote regions of +our optic powers, islet on islet of scattered nebulae. The feeling of the +sublime, so far as it arises from a contemplation of the distance of the +stars, of their greatness and physical extent, reflects itself in the +feeling of the infinite, which belongs to another sphere of ideas included +in the domain of mind. The solemn and imposing impressions excited by this +sentiment are owing to the combination of which we have spoken, and to the +analogous character of the enjoyment and emotions awakened in us, whether we +float on the surface of the great deep, stand on some lonely mountain summit +enveloped in the half-transparent vapory vail of the atmosphere, or by the +aid of powerful optical instruments scan the regions of space, and see the +remote nebulous mass resolve itself into worlds of stars. + +The mere accumulation of unconnected observations of details, devoid of +generalization of ideas, may doubtlessly have tended to create and foster +the deeply-rooted prejudice, that the study of the exact sciences must +necessarily chill the feelings, and diminish the nobler enjoyments attendant +upon a contemplation of nature. Those who still cherish such erroneous +views in the present age, and amid the progress of public opinion, and the +advancement of all branches of knowledge, fail in duly appreciating the +value of every enlargement of the sphere of intellect, and the importance of +the detail of isolated facts in leading us on to general results. The fear +of sacrificing the free enjoyment of nature, under the influence of +scientific reasoning, is often associated with an apprehension that every +mind may not be capable of grasping the truths of the philosophy of nature. +It is certainly true that in the midst of the universal fluctuation of +phenomena and vital +p 41 +forces -- in that inextricable net-work of organisms by turns developed and +destroyed -- each step that we make in the more intimate knowledge of nature +leads us to the entrance of new labyrinths; but the excitement produced by a +presentiment of discovery, the vague intuition of the mysteries to be +unfolded, and the multiplicity of the paths before us, all tend to stimulate +the exercise of thought in every stage of knowledge. The discovery of each +separate law of nature leads to the establishment of some other more general +law, or at least indicates to the intelligent observer its existence. +Nature, as a celebrated physiologist* has defined it, and as the word was +interpreted by the Greeks and Romans, is "that which is ever growing and +ever unfolding itself in new forms." + + +[Footnote] *Carus, 'Von den Urtheilen des Knochen und Schalen Gerustes', +1828 6. + + +The series of organic types becomes extended or perfected in proportion as +hitherto unknown regions are laid open to our view by the labors and +researches of travelers and observers; as living organisms are compared with +those which have disappeared in the great revolutions of our planet; and as +microscopes are made more perfect, and are more extensively and efficiently +employed. In the midst of this immense variety, and this periodic +transformation of animal and vegetable productions, we see incessantly +revealed the primordial mystery of all organic development, that same great +problem of 'metamorphosis' which Göthe has treated with more than common +sagacity, and to the solution of which man is urged by his desire of +reducing vital forms to the smallest number of fundamental types. As men +contemplate the riches of nature, and see the mass of observations +incessantly increasing before them, they become impressed with the intimate +conviction that the surface and the interior of the earth, the depths of the +ocean, and the regions of air will still, when thousands and thousands of +years have passed away, open to the scientific observer untrodden paths of +discovery. The regret of Alexander can not be applied to the progress of +observation and intelligence.* + + +[footnote] * Plut., in 'Vita Alex. Magni', cap. 7 + + +General considerations, whether they treat of the agglomeration of matter in +the heavenly bodies, or of the geographical distribution of terrestrial +organisms, are not only in themselves more attractive than special studies, +but they also afford superior advantages to those who are unable to devote +much time to occupations of this nature. The different branches of the +study of natural history are only accessible in certain positions of social +life, and do not, at every season +p 42 +and in every climate, present like enjoyments. Thus, in the dreary regions +of the north, man is deprived for a long period of the year of the spectacle +presented by the activity of the productive forces of organic nature; and if +the mind be directed to one sole class of objects, the most animated +narratives of voyages in distant lands will fail to interest and attract us, +if they do not touch upon the subjects to which we are most partial. + +As the history of nations -- if it were always able to trace events to their +true causes -- might solve the ever-recurring enigma of the oscillations +experienced by the alternately progressive and retrograde movement of human +society, so might also the physical description of the world, the science of +the 'Cosmos', if it were grasped by a powerful intellect, and based upon a +knowledge of all the results of discovery up to a given period, succeed in +dispelling a portion of the contradictions which, at first sight, appear to +arise from the complication or phenomena and the multitude of the +perturbations simultaneously manifested. + +The knowledge of the laws of nature, whether we can trace them in the +alternate ebb and flow of the ocean, in the measured path of comets, or in +the mutual attractions of multiple stars, alike increases our sense of the +calm of nature, while the chimera so long cherished by the human mind in its +early and intuitive contemplations, the belief in a "discord of the +elements," seems gradually to vanish in proportion as science extends her +empire. General views lead us habitually to consider each organism as a +part of the entire creation, and to recognize in the plant or the animal not +merely an isolated species, but a form linked in the chain of being to other +forms either living or extinct. They aid us in comprehending the relations +that exist between the most recent discoveries and those which have prepared +the way for them. Although fixed to one point of space, we eagerly grasp at +a knowledge of that which has been observed in different and far-distant +regions. We delight in tracking the course of the bold mariner through seas +of polar ice, or in following him to the summit of that volcano of the +antarctic pole, whose fires may be seen from afar, even at mid-day. It is +by an acquaintance with the results of distant voyages that we may learn to +comprehend some of the marvels of terrestrial magnetism, and be thus led to +appreciate the importance of the establishments of the numerous +observatories which in the present day cover both hemispheres, and are +designed to note +p 43 +the simultaneous occurrence of perturbations, and the frequency and duration +of 'magnetic storms.' + +Let me be permitted here to touch upon a few points connected with +discoveries, whose importance can only be estimated by those who have +devoted themselves to the study of the physical sciences generally. +Examples chosen from among the phenomena to which special attention has been +directed in recent times, will throw additional light upon the preceding +considerations. Without a preliminary knowledge of the orbits of comets, we +should be unable duly to appreciate the importance attached to the discovery +of one of these bodies, whose elliptical orbit is included in the narrow +limits of our solar system, and which has revealed the existence of an +ethereal fluid, tending to diminish its centrifugal force and the period of +its revolution. + +The superficial half-knowledge, so characteristic of the present day, which +leads to the introduction of vaguely comprehended scientific views into +general conversation, also gives rise, under various forms, to the +expression of alarm at the supposed danger of a collision between the +celestial bodies, or of disturbance in the climatic relations of our globe. +These phantoms of the imagination are so much the more injurious as they +derive their source from dogmatic pretensions to true science. The history +of the atmosphere, and of the annual variations of its temperature, extends +already sufficiently far back to show the recurrence of slight disturbances +in the mean temperature of any given place, and thus affords sufficient +guarantee against the exaggerated apprehension of a general and progressive +deterioration of the climates of Europe. Encke's comet, which is one of the +three 'interior comets', completes its course in 1200 days, but from the +form and position of its orbit it is as little dangerous to the earth as +Halley's great comet, whose revolution is not completed in less than +seventy-six years (and which appeared less brilliant in 1835 than it had +done in 1759): the interior comet of Biela intersects the earth's orbit, it +is true, but it can only approach our globe when its proximity to the sun +coincides with our winter solstice. + +The quantity of heat received by a planet, and whose unequal distribution +determines the meteorological variations of its atmosphere, depends alike +upon the light-engendering force of the sun; that is to say, upon the +condition of its gaseous coverings, and upon the relative position of the +planet and the central body. + +p 44 +There are variations, it is true, which, in obedience to the laws of +universal gravitation, affect the form of the earth's orbit and the +inclination of the ecliptic, that is, the angle which the axis of the earth +makes with the plane of its orbit; but these periodical variations are so +slow, and are restricted within such narrow limits, that their thermic +effects would hardly be appreciable by our instruments in many thousands of +years. The astronomical causes of a refrigeration of our globe, and of the +diminution of moisture at its surface, and the nature and frequency of +certain epidemics -- phenomena which are often discussed in the present day +according to the benighted views of the Middle Ages -- ought to be +considered as beyond the range of our experience in physics and chemistry. + +Physical astronomy presents us with other phenomena, which can not be fully +comprehended in all their vastness without a previous acquirement of general +views regarding the forces that govern the universe. Such, for instance, +are the innumerable double stars, or rather suns, which revolve round one +common center of gravity, and thus reveal in distant worlds the existence of +the Newtonian law; the larger or smaller number of spots upon the sun, that +is to say, the openings formed through the luminous and opaque atmosphere +surrounding the solid nucleus; and the regular appearance about the 13th of +November and the 11th of August, of shooting stars, which probably form part +of a belt of asteroids, intersecting the earth's orbit, and moving with +planetary velocity. + +Descending from the celestial regions to the earth, we would fain inquire +into the relations that exist between the oscillations of the pendulum in +air (the theory of which has been perfected by Bessel) and the density of +our planet; and how the pendulum, acting the part of a plummet, can, to a +certain extent, throw light upon the geological constitution of strata at +great depths? By means of this instrument we are enabled to trace the +striking analogy which exists between the formation of the granular rocks +composing the lava currents ejected from active volcanoes, and those +endogenous masses of granite, porphyry, and serpentine, which, issuing from +the interior of the earth, have broken, as eruptive rocks, through the +secondary strata, and modified them by contact, either in rendering them +harder by the introduction of silex, or reducing them into dolomite, or, +finally, by inducing within them the formation of crystals of the most +varied composition. The elevation of sporadic islands, of +p 45 +domes of trachyte, and cones of basalt, by the elastic forces emanating from +the fluid interior of our globe, has led one of the first geologists of the +age, Leopold von Buch, to the theory of the elevation of continents, and of +mountain chains generally. This action of subterranean forces in breaking +through and elevating strata of sedimentary rocks, of which the coast of +Chili, in consequence of a great earthquake, furnished a recent example, +leads to the assumption that the pelagic shells found by M. Bonpland and +myself on the ridge of the Andes, at an elevation of more than 15,000 +English feet, may have been conveyed to so extraordinary a position, not by +a rising of the ocean, but by the agency of volcanic forces capable of +elevating into ridges the softened crust of the earth. + +I apply the term 'volcanic', in the widest sense of the word, to every +action exercised by the interior of a planet on its external crust. The +surface of our globe, and that of the moon, manifest traces of this action, +which in the former, at least, has varied during the course of ages. Those +who are ignorant of the fact that the internal heat of the earth increases +so rapidly with the increase of depth that granite is in a state of fusion +about twenty or thirty geographical miles below the surface,* can not have a +clear conception of the causes, and the simultaneous occurrence of volcanic +eruptions at places widely removed from one another, or of the extent and +intersection of 'circles of commotion' in earthquakes, or of the uniformity +of temperature, and equality of chemical composition observed in thermal +springs during a long course of years. + + +[Footnote] * The determinations usually given of the point of fusion are in +general much too high for refracting substances. According to the very +accurate researches of Mitscherlich, the melting point of granite can hardly +exceed 2372 degrees F. +[Dr. Mantell states in 'The Wonders of Geology', 1848, vol. i., p. 34, that +this increase of temperature amounts to 1 degree of Fahrenheit for every +fifty-four feet of vertical depth.] -- Tr. + + +The quantity of heat peculiar to a planet is, however, a matter of such +importance -- being the result of its primitive condensation, and varying +according to the nature and duration of the radiation -- that the study of +this subject may throw some degree of light on the history of the +atmosphere, and the distribution of the organic bodies imbedded in the solid +crust of the earth. This study enables us to understand how a tropical +temperature, independent of latitude (that is, of the distance from the +poles), may have been produced by deep fissures remaining open, and exhaling +heat from the interior +p 46 +of the globe, at a period when the earth's crust was still furrowed and +rent, and only in a state of semi-solidification; and a primordial condition +is thus revealed to us, in which the temperature of the atmosphere, and +climates generally, were owing rather to a liberation of caloric and of +different gaseous emanations (that is to say, rather to the energetic +reaction of the interior on the exterior) than to the position of the earth +with respect to the central body, the sun. + +The cold regions of the earth contain, deposited in sedimentary strata, the +products of tropical climates; thus, in the coal formations, we find the +trunks of palms standing upright amid coniferae, tree ferns, goniatites, and +fishes having rhomboidal osseous scales;* in the Jura limestone, colossal +skeletons of crocodiles, plesiosauri, planulites, and stems of the cycadeae; +in the chalk formations, small polythalmia and bryozoa, whose species still +exist in our seas; in tripoli, or polishing slate, in the semi-opal and the +farina-like opal or mountain meal, agglomerations of siliceous infusoria, +which have been brought to light by the powerful microscope of Ehrenberg;** +and, lastly, in transported soils, and in certain caves, the bones of +elephants, hyenas, and lions. + +[Footnote] *See the classical work on the fishes of the Old World by +Agassiz, 'Rech. sur les Poissons Fossiles', 1834, vol. i., p. 38; vol. ii., +p. 3, 28, 34, App., p. 6. The whole genus of Amblypterus, Ag., nearly +allied to Palaeoniscus (called also Palaeothrissum), lies buried beneath the +Jura formations in the old carboniferous strata. Scales which, in some +fishes, as in the family of Lepidoides (order of Ganoides), are formed like +teeth, and covered in certain parts with enamel, belong, after the +Placoides, to the oldest forms of fossil fishes; their living +representatives are still found in two genera, the 'Bichir' of the Nile and +Senegal, and the 'Lepidosteus' of the Ohio. + + +[Footnote] **[The 'polishing slate' of Bilin is stated by M. Ehrenberg to +form a 'series' of strata fourteen feet in thickness, entirely made up of +the siliceous shells of 'Gaillonellae', of such extreme minuteness that a +cubic inch of the stone contains forty-one thousand millions! The +'Bergmehl' ('mountain meal' or 'fossil farina') of San Fiora, in Tuscany, is +one mass of animalculites. See the interesting work of G. A. Mantell, 'On +the Medals of Creation', vol. i., p. 233.] -- Tr. + + +An intimate acquaintance with the physical phenomena of the universe leads +us to regard the products of warm latitudes that are thus found in a fossil +condition in northern regions not merely as incentives to barren curiosity, +but as subjects awakening deep reflection, and opening new sources of study. + +The number and the variety of the objects I have alluded to give rise to the +question whether general considerations of physical phenomena can be made +sufficiently clear to persons who have not acquired a detailed and special +knowledge of +p 47 +descriptive natural history, geology, or mathematical astronomy? I think we +ought to distinguish here between him whose task it is to collect the +individual details of various observations, and study the mutual relations +existing among them, and him to whom these relations are to be revealed, +under the form of general results. The former should be acquainted with the +specialities of phenomena, that he may arrive at a generalization of ideas +as the result, at least in part, of his own observations, experiments, and +calculations. It can not be denied, that where there is an absence of +positive knowledge of physical phenomena, the general results which impart +so great a charm to the study of nature can not all be made equally clear +and intelligible to the reader, but still I venture to hope, that in the +work which I am now preparing on the physical laws of the universe, the +greater part of the facts advanced can be made manifest without the +necessity of appealing to fundamental views and principles. The picture of +nature thus drawn, notwithstanding the want of distinctness of some of its +outlines, will not be the less able to enrich the intellect, enlarge the +sphere of ideas, and nourish and vivify the imagination. + +There is, perhaps, some truth in the accusation advanced against many German +scientific works, that they lessen the value of general views by an +accumulation of detail, and do not sufficiently distinguish between those +great results which form, as it were, the beacon lights of science, and the +long series of means by which they have been attained. This method of +treating scientific subjects led the most illustrious of our poets* to +exclaim with impatience, "The Germans have the art of making science +inaccessible." An edifice can not produce a striking effect until the +scaffolding is removed, that had of necessity been used during its erection. + +[Footnote] *Gothe, in 'Die Aphorismen uber Naturwissenschaft', bd. I., s. +155 ('Werke kleine Ausgabe','von' 1833.) + + +Thus the uniformity of figure observed in the distribution of continental +masses, which all terminate toward the south in a pyramidal form, and expand +toward the north (a law that determines the nature of climates, the +direction of currents in the ocean and the atmosphere, and the transition of +certain types of tropical vegetation toward the southern temperate zone), +may be clearly apprehended without any knowledge of the geodesical and +astronomical operations by means of which these pyramidal forms of +continents have been determined. In like manner, physical geography teaches +us by how many leagues +p 48 +the equatorial axis exceeds the polar axis of the globe, and shows us the +mean equality of the flattening of the two hemispheres, without entailing on +us the necessity of giving the detail of the measurement of the degrees in +the meridian, or the observations on the pendulum, which have led us to know +that the true figure of our globe is not exactly that of a regular ellipsoid +of revolution, and that this irregularity is reflected in the corresponding +irregularity of the movements of the moon. + +The views of comparative geography have been specially enlarged by that +admirable work, 'Erdkunde im Verhältniss zur Natur und sur Geschichte', in +which Carl Ritter so ably delineates the physiognomy of our globe, and shows +the influence of its external configuration on the physical phenomena on its +surface, on the migrations, laws, and manners of nations, and on all the +principal historical events enacted upon the face of the earth. + +France possesses an immortal work, 'L'Exposition du Système du Monde', in +which the author has combined the results of the highest astronomical and +mathematical labors, and presented them to his readers free from all +processes of demonstration. The structure of the heavens is here reduced to +the simple solution of a great problem in mechanics; yet Laplace's work has +never yet been accused of incompleteness and want of profundity. + +The distinction between dissimilar subjects, and the separation of the +general from the special, are not only conducive to the attainment of +perspicuity in the composition of a physical history of the universe, but +are also the means by which a character of greater elevation may be imparted +to the study of nature. By the suppression of all unnecessary detail, the +great masses are better seen, and the reasoning faculty is enabled to grasp +all that might otherwise escape the limited range of the senses. + +The exposition of general results has, it must be owned, been singularly +facilitated by the happy revolution experienced since the close of the last +century, in the condition of all the special sciences, more particularly of +geology, chemistry, and descriptive natural history. In proportion as laws +admit of more general application, and as sciences mutually enrich each +other, and by their extension become connected together in more numerous and +more intimate relations, the development of general truths may be given with +conciseness devoid of superficiality. On being first examined, all +phenomena appear to be +p 49 +isolated, and it is only by the result of a multiplicity of observations, +combined by reason, that we are able to trace the mutual relations existing +between them. If, however, in the present age, which is so strongly +characterized by a brilliant course of scientific discoveries, we perceive a +want of connection in the phenomena of certain sciences, we may anticipate +the revelation of new facts, whose importance will probably be commensurate +with the attention directed to these branches of study. Expectations of +this nature may be entertained with regard to meteorology, several parts of +optics, and to radiating heat, and electro-magnetism, since the admirable +discoveries of Melloni and Faraday. A fertile field is here opened to +discovery, although the voltaic pile has already taught us the intimate +connection existing between electric, magnetic, and chemical phenomena. Who +will venture to affirm that we have any precise knowledge, in the present +day, of that part of the atmosphere which is not oxygen, or that thousands +of gaseous substances affecting our organs may not be mixed with the +nitrogen, or, finally, that we have even discovered the whole number of the +forces which pervade the universe? + +It is not the purpose of this essay on the physical history of the world to +reduce all sensible phenomena to a small number of abstract principles, +based on reason only. The physical history of the universe, whose +exposition I attempt to develop, does not pretend to rise to the perilous +abstractions of a purely rational science of nature, and is simply a +'physical geography, combined with a description of the regions of space and +the bodies occupying them.' Devoid of the profoundness of a purely +speculative philosophy, my essay on the 'Cosmos' treats of the contemplation +of the universe, and is based upon a rational empiricism, that is to say, +upon the results of the facts registered by science, and tested by the +operations of the intellect. It is within these limits alone that the work, +which I now venture to undertake, appertains to the sphere of labor to which +I have devoted myself throughout the course of my long scientific career. +The path of inquiry is not unknown to me, although it may be pursued by +others with greater success. The unity which I seek to attain in the +development of the great phenomena of the universe, is analogous to that +which historical composition is capable of acquiring. All points relating +to the accidental individualities, and the essential variations of the +actual, whether in the form and arrangement of natural objects in the +struggle of man against the elements, or of nations against nations, do not +admit of being +p 50 +based only on a 'rational foundation' -- that is to say, of being deduced +from ideas alone. + +It seems to me that a like degree of empiricism attaches to the Description +of the Universe and to Civil History; but in reflecting upon physical +phenomena and events, and tracing their causes by the process of reason, we +become more and more convinced of the truth of the ancient doctrine, that +the forces inherent in matter, and those which govern the moral necessity, +and in accordance with movements occurring periodically after longer or +shorter intervals. + +It is this necessity, this occult but permanent connection, this periodical +recurrence in the progressive development of forms, phenomena, and events, +which constitute 'nature', obedient to the first impulse imparted to it. +Physics, as the term signifies, is limited to the explanation of the +phenomena of the material world by the properties of matter. The ultimate +object of the experimental sciences is, therefore, to discover laws, and to +trace their progressive generalization. All that exceeds this goes beyond +the province of the physical description of the universe, and appertains to +a range of higher speculative views. + +Emmanuel Kant, one of the few philosophers who have escaped the imputation +of impiety, has defined with rare sagacity the limits of physical +explanations, in his celebrated essay 'On the Theory and Structure of the +Heavens', published at Konigsberg in 1755. + +The study of a science that promises to lead us through the vast range of +creation may be compared to a journey in a far-distant land. Before we set +forth, we consider, and often with distrust, our own strength, and that of +the guide we have chosen. But the apprehensions which have originated in +the abundance and the difficulties attached to the subjects we would +embrace, recede from view as we remember that with the increase of +observations in the present day there has also arisen a more intimate +knowledge of the connection existing among all phenomena. It has not +unfrequently happened, that the researches made at remote distances have +often and unexpectedly thrown light upon subjects which had long resisted +the attempts made to explain them within the narrow limits of our own sphere +of observation. Organic forms that had long remained isolated, both in the +animal and vegetable kingdom, have been connected by the discovery of +intermediate links or stages of transition. The geography of beings endowed +p 51 +with life attains completeness as we see the species, genera, and entire +families belonging to one hemisphere, reflected as it were, in analogous +animal and vegetable forms in the opposite hemisphere. There are, so to +speak, the 'equivalents' which mutually personate and replace one another in +the great series of organisms. These connecting links and stages of +transition may be traced, alternately, in a deficiency or an excess of +development of certain parts, in the mode of junction of distinct organs, in +the differences in the balance of forces, or in a resemblance to +intermediate forms which are not permanent, but merely characteristic of +certain phases of normal development. Passing from the consideration of +beings endowed with life to that of inorganic bodies, we find many striking +illustrations of the high state of advancement to which modern geology has +attained. We thus see, according to the grand views of Elie de Beaumont, +how chains of mountains dividing different climates and floras and different +races of men, reveal to us their 'relative age', both by the character of +the sedimentary strata they have uplifted, and by the directions which they +follow over the long fissures and which the earth's crust is furrowed. +Relations of superposition of trachyte and of syenitic porphyry, of diorite +and of serpentine, which remain in the rich platinum districts of the Oural, +and on the south-western declivity of the Siberian Alti, are elucidated by +the observations that have been made on the plateaux of Mexico and +Antioquia, and in the unhealthy ravines of Choco. The most important facts +on which the physical history of the world has been based in modern times, +have not been accumulated by chance. It has at length been fully +acknowledged, and the conviction is characteristic of the age, that the +narratives of distant travels, too long occupied in the mere recital of +hazardous adventures, can only be made a source of instruction where the +traveler is acquainted with the condition of the science he would enlarge, +and is guided by reason in his researches. + +It is by this tendency to generalization, which is only dangerous in its +abuse, that a great portion of the physical knowledge already acquired may +be made the common property of all classes of society; but, in order to +render the instruction impaired by these means commensurate with the +importance of the subject, it is desirable to deviate as widely as possible +from the imperfect compilations designated, till the close of the eighteenth +century, by the inappropriate term of 'popular +p 52 +knowledge.' I take pleasure in persuading myself that scientific subjects +may be treated of in language at once dignified, grave, and animated, and +that those who are restricted within the circumscribed limits of ordinary +life, and have long remained strangers to an intimate communion with nature, +may thus have opened to them one of the richest sources of enjoyment, by +which the mind is invigorated by the acquisition of new ideas. Communion +with nature awakens within us perceptive faculties that had long lain +dormant; and we thus comprehend at a single glance the influence exercised +by physical discoveries on the enlargement of the sphere of intellect, and +perceive how a judicious application of mechanics, chemistry, and other +sciences may be made conducive to national prosperity. + +A more accurate knowledge of the connection of physical phenomena will also +tend to remove the prevalent error that all branches of natural science are +not equally important in relation to general cultivation and industrial +progress. An arbitrary distinction is frequently made between the various +degrees of importance appertaining to mathematical sciences, to the study of +organized beings, the knowledge of electro-magnetism, and investigations of +the general properties of matter in its different conditions of molecular +aggregation; and it is not uncommon presumptuously to affix a supposed +stigma upon researches of this nature, by terming them "purely theoretical," +forgetting , although the fact has been long attested, that in the +observation of a phenomenon, which at first sight appears to be wholly +isolated, may be concealed the germ of a great discovery. When Aloysio +Galvani first stimulated the nervous fiber by the accidental contact of two +heterogeneous metals, his contemporaries could never have anticipated that +the action of the voltaic pile would discover to us, in the alkalies, metals +of a silvery luster, so light as to swim on water, and eminently +inflammable; or that it would become a powerful instrument of chemical +analysis, and at the same time a thermoscope and a magnet. When Hygens +first observed, in 1678, the phenomenon of the polarization of light, +exhibited in the difference between the two rays into which a pencil of +light divides itself in passing through a doubly refracting crystal, it +could not have been foreseen that, a century and a half later, the great +philosopher Arago would, by his discovery of 'chromatic polarization', be +led to discern, by means of a small fragment of Iceland spar, whether solar +light emanates from a solid body or a gaseous covering, or +p 53 +whether comets transmit light directly or merely by reflection.* + + +[Footnote] *Arago's Discoveries in the year 1811. -- Delambro's 'Histoire +de l'Ast.', p. 652. (Passage already quoted.) + + +An equal appreciation of all branches of the mathematical, physical, and +natural sciences is a special requirement of the present age, in which the +material wealth and the growing prosperity of nations are principally based +upon a more enlightened employment of the products and forces of nature. +The most superficial glance at the present condition of Europe shows that a +diminution, or even a total annihilation of national prosperity, must be the +award of those states who shrink with slothful indifference from the great +struggle of rival nations in the career of the industrial arts. It is with +nations as with nature, which, according to a happy expression of Göthe,* +"knows no pause in progress and development, and attaches her curse on all +inaction." + + +[Footnote] *Gothe, in 'Die Aphorismen uber Naturwissenschaft.' -- 'Werke', +bd. 1., s. 4 + + +The propagation of an earnest and sound knowledge of science can therefore +alone avert the dangers of which I have spoken. Man can not act upon +nature, or appropriate her forces to his own use, without comprehending +their full extent, and having an intimate acquaintance with the laws of the +physical world. Bacon has said that, in human societies, knowledge is +power. Both must rise and sink together. But the knowledge that results +from the free action of thought is at once the delight and the +indestructible prerogative of man; and in forming part of the wealth of +mankind, it not unfrequently serves as a substitute for the natural riches, +which are but sparingly scattered over the earth. Those states which take +no active part in the general industrial movement, in the choice and +preparation of natural substances, or in the application of mechanics and +chemistry, and among whom this activity is not appreciated by all classes of +society, will infallibly see their prosperity diminish in proportion as +neighboring countries become strengthened and invigorated under the genial +influence of arts and sciences. + +As in nobler spheres of thought and sentiment, in philosophy, poetry, and +the fine arts, the object at which we aim ought to be an inward one -- an +ennoblement of the intellect -- so ought we likewise in our pursuit of +science, to strive after a knowledge of the laws and the principles of unity +that pervade the vital forces of the universe; and it is by such a course +that +p 54 +physical studies may be made subservient to the progress of industry, which +is a conquest of mind over matter. By a happy connection of causes and +effects, we often see the useful linked to the beautiful and the exalted. +The improvement of agriculture in the hands of freemen, and on properties of +a moderate extent -- the flourishing state of the mechanical arts freed from +the trammels of municipal restrictions -- the increased impetus imparted to +commerce by the multiplied means of the intellectual progress of mankind, +and of the amelioration of political institutions, in which this progress is +reflected. The picture presented by modern history ought to convince those +who are tardy in awakening to the truth of the lesson it teaches. + +Nor let it be feared that the marked predilection for the study of nature, +and for industrial progress, which is so characteristic of the present age, +should necessarily have a tendency to retard the noble exertions of the +intellect in the domains of philosophy, classical history, and antiquity, or +to deprive the arts by which life is embellished of the vivifying breath of +imagination. Where all the germs of civilization are developed beneath the +aegis of free institutions and wise legislation, there is no cause for +apprehending that any one branch of knowledge should be cultivated to the +prejudice of others. All afford the state precious fruits, whether they +yield nourishment to man and constitute his physical wealth, or whether, +more permanent in their nature, they transmit in the works of mind the glory +of nations to remotest posterity. The Spartans, notwithstanding their Doric +austerity, prayed the gods to grant them "the beautiful with the good."* + + +[Footnote] *Pseudo-Plato, -- 'Alcib.', xi., p. 184, ed. Steph.; Plut., +'Instituta Laconica', p. 253, ed. Hatten. + + +I will no longer dwell upon the considerations of the influence exercised by +the mathematical and physical sciences on all that appertains to the +material wants of social life, for the vast extent of the course on which I +am entering forbids me to insist further upon the utility of these +applications. Accustomed to distant excursions, I may, perhaps, have erred +in describing the path before us as more smooth and pleasant than it really +is, for such is wont to be the practice of those who delight in guiding +others to the summits of lofty mountains: they praise the view even when +great part of the distant plains lie hidden by clouds, knowing that this +half-transparent vapory vail imparts to the scene a certain charm from +p 55 +the power exercised by the imagination over the domain of the senses. In +like manner, from the height occupied by the physical history of the world, +all parts of the horizon will not appear equally clear and well defined. +This indistinctness will not, however, be wholly owing to the present +imperfect state of some of the sciences, but in part, likewise, to the +unskillfulness of the guide who has imprudently ventured to ascend these +lofty summits. + +The object of this introductory notice is not, however, solely to draw +attention to the importance and greatness of the physical history of the +universe, for in the present day these are too well understood to be +contested, but likewise to prove how, without detriment to the stability of +special studies, we may be enabled to generalize our ideas by concentrating +them in one common focus, and thus arrive at a point of view from which all +the organisms and forces of nature may be seen as one living active whole, +animated by one sole impulse. "Nature," as Schelling remarks in his poetic +discourse on art, "is not an inert mass; and to him who can comprehend her +vast sublimity, she reveals herself as the creative force of the universe -- +before all time, eternal, ever active, she calls to life all things, whether +perishable or imperishable." + +By uniting, under one point of view, both the phenomena of our own globe and +those presented in the regions of space, we embrace the limits of the +science of the 'Cosmos', and convert the physical history of the globe into +the physical history of the universe, the one term being modeled upon that +of the other. This science of the Cosmos is not, however, to be regarded as +a mere encyclopedic aggregation of the most important and general results +that have been collected together from special branches of knowledge. These +results are nothing more than the materials for a vast edifice, and their +combination can not constitute the physical history of the world, whose +exalted part it is to show the simultaneous action and the connecting links +of the forces which pervade the universe. The distribution of organic types +in different climates and at different elevations -- that is to say, the +geography of plants and animals -- differs as widely from botany and +descriptive zoology as geology does from mineralogy, properly so called. +The physical history of the universe must not, therefore, be confounded with +the 'Encyclopedias of the Natural Sciences', as they have hitherto been +compiled, and whose title is as vague as their limits are ill defined. In +the work before us, partial facts will be considered only in relation to the +whole. +p 56 +The higher the point of view, the greater is the necessity for a systematic +mode of treating the subject in language at once animated and picturesque. + +But thought and language have ever been most intimately allied. If +language, by its originality of structure and its native richness, can, in +its delineations, interpret thought with grace and clearness, and if, by its +happy flexibility, it can paint with vivid truthfulness the objects of the +external world, it reacts at the same time upon thought, and animates it, as +it were, with the breath of life. It is this mutual reaction which makes +words more than mere signs and forms of thought; and the beneficent +influence of a language is most strikingly manifested on its native soil, +where it has sprung spontaneously from the minds of the people, whose +character it embodies. Proud of a country that seeks to concentrate her +strength in intellectual unity, the writer recalls with delight the +advantages he has enjoyed in being permitted to express his thoughts in his +native language; and truly happy is he who, in attempting to give a lucid +exposition of the great phenomena of the universe, is able to draw from the +depths of a language, which, through the free exercise of thought, and by +the effusions of creative fancy, has for centuries past exercised so +powerful an influence over the destinies of man. + + + +This material taken from pages 56 to 78 + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p 56 + +LIMITS AND METHOD OF EXPOSITION OF THE PHYSICAL DESCRIPTION OF THE UNIVERSE. + +I HAVE endeavored, in the preceding part of my work, to explain and +illustrate, by various examples, how the enjoyments presented by the aspect +of nature, varying as they do in the sources from when they flow, may be +multiplied and ennobled by an acquaintance with the connection of phenomena +and the laws by which they are regulated. It remains, then, for me to +examine the spirit of the method in which the exposition of the 'physical +description of the universe' should be conducted, and to indicate the limits +of this science in accordance with the views I have acquired in the course +of my studies and travels in various parts of the earth. I trust I may +flatter myself with a hope that a treatise of this nature will justify the +title I have ventured to adopt for my work, and exonerate me from the +reproach of a presumption that would be doubly reprehensible in a scientific +discussion. + +Before entering upon the delineation of the partial phenomena +p 57 +which are found to be distributed in various groups, I would consider a few +general questions intimately connected together, and bearing upon the nature +of our knowledge of the external world and its different relations, in all +epochs of history and in all phases of intellectual advancement. Under this +head will be comprised the following considerations: + +1. The precise limits of the physical description of the universe, +considered as a distinct science. + +2. A brief enumeration of the totality of natural phenomena, presented +under the form of a 'general delineation of nature.' + +3. The influence of the external world on the imagination and feelings, +which has acted in modern times as a powerful impulse toward the study of +natural science, by giving animation to the description of distant regions +and to the delineation of natural scenery, as far as it is characterized by +vegetable physiognomy and by the cultivation of exotic plants, and their +arrangement in well-contrasted groups. + +4. The history of the contemplation of nature, or the progressive +development of the idea of the Cosmos, considered with reference to the +historical and geographical facts that have led to the discovery of the +connection of phenomena. + +The higher the point of view from which natural phenomena may be considered, +the more necessary it is to circumscribe the science within its just limits, +and to distinguish it from all other analogous or auxiliary studies. + +Physical cosmography is founded on the contemplation of all created things +-- all that exists in space, whether as substances or forces -- that is, all +the material beings that constitute the universe. The science which I would +attempt to define presents itself, therefore, to man, as the inhabitant of +the earth, under a two-fold form -- as the earth itself and the regions of +space. It is with a view of showing the actual character and the +independence of the study of physical cosmography, and at the same time +indicating the nature of its relations to 'general physics, descriptive +natural history, geology, and comparative geography', that I will pause for +a few moments to consider that portion of the science of the Cosmos which +concerns the earth. As the history of philosophy does not consist of a mere +material enumeration of the philosophical views entertained in different +ages, neither should the physical description of the universe be a simple +encyclopedic compilation of the sciences we have enumerated. The difficulty +of defining the limits of intimately-connected studies has been increased, +because for centuries it has been customary to designate various branches +p 58 +of empirical knowledge by terms which admit either of too wide or too +limited a definition of the ideas which they were intended to convey, and +are, besides, objectionable from having had a different signification in +those classical languages of antiquity from thish chey have been borrowed. +The terms physiology, physics, natural history, geology and geography arose, +and were commonly used, long before clear ideas were entertained of the +diversity of objects embraced by these sciences, and consequently of their +reciprocal limitation. Such is the influence of long habit upon language, +that by one of the nations of Europe most advanced in civilization the word +"physic" is applied to medicine, while in a society of justly deserved +universal reputation, technical chemistry, geology and astronomy (purely +experimental sciences) are comprised under the head of "Philosophical +Transactions." + +An attempt has often been made, and almost always in vain, to substitute new +and more appropriate terms for these ancient designations, which, +notwithstanding their undoubted vagueness, are now generally understood. +These changes have been proposed, for the most part, by those who have +occupied themselves with the general classification of the various branches +of knowledge, from the first appearance of the great encyclopedia +('Margarita Philosophica') of Gregory Reisch,* prior of the Chartreuse at +Freiburg, toward the close of the fifteenth century, to Lord Bacon, and from +Bacon to D'Alembert; and in recent times to an eminent physicist, Andre +Marie Ampere.** + + +[footnote] *The 'Margarita Philosophica' of Gregory Reisch, prior of the +Chartreuse at Freiburg, first appeared under the following title: Aepitome +omnis Philosophiæ, alias Margarita Philosophica, tractans de omni generi +scibili. The Heidelberg edition (1486), and that of Strasburg (1504), both +bear this title, but the first part was suppressed in the Freiburg edition +of the same year, as well as in the twelve subsequent editions, which +succeeded one another, at short intervals, till 1535. This work exercised a +great influence on the diffusion of mathematical and physical sciences +toward the beginning of the sixteenth century, and Crasles, the learned +author of 'L'Aperçu Historique des Methodes en Géometrica' (1837) has +shown the great importance of Reisch's 'Encyclopedia' in the history of +mathematics in the Middle Ages. I have had recourse to a passage in the +'Margarita Philosophica', found only in the edition of 1513, to elucidate +the important question of the relations between the statements of the +geographer of Saint-Die, Hylacomilus (Martin Waldseemuller), the first who +gave the name of America to the New Continent, and those of Amerigo +Vespucci, Rene, King of Jerusalem and Duke of Lorraine, as also those +contained in the celebrated editions of Ptolemy of 1513 and 1522. See my +'Examen Critique de la Gegraphie du Nouveau Continent, et des Progres de +l'Astronomie Nautique aux 15e et 16e Siecles', t. iv., p. 99-125. + + +[footnote] II Ampère, 'Essai sur la Phil. des Sciences', 1834, p. 25. +Whewell, 'Philosophy of the Inductive Sciences', vol. ii., p. 277. Park, +'Pantology', p. 87. + + +p 59 +The selection of an inappropriate Greek nomenclature has perhaps been even +more prejudicial to the last of these attempts than the injudicious use of +binary divisions and the excessive multiplication of groups. + +The physical description of the world, considering the universe as an object +of the external senses, does undoubtedly require the aid of general physics +and of descriptive natural history, but thecontemplation of all created +things, which are linked together, and form one 'whole', animated by +internal forces, given to the science we are considering a peculiar +character. Phyical science considers only the general properties of bodies; +it is the product of abstraction -- a generalization of perceptible +phenomena; and even in the work in which were laid the first foundations of +general physics, in the eight books on physics of Aristotle,* all the +phenomena of nature are considered as depending upon the primitive and vital +action of one sole force, from which emaate all the movements of the +universe. + + +[footnote] * All changes in the physical world may be reduced to motion. +Aristot., 'Phys. Ausc.', iii., 1 and 4, p. 200, 201. Bekker, viii., 1, 8, +and 9, p. 250, 262, 265. 'De Genere et Corr.', ii., 10, p. 336. +Pseudo-Aristot., 'De Mundo.' cap. vi., p. 398. + + +The terrestrial portion of physical cosmography, for which I would willingly +retain the expressive designation of 'physical geography', treats of the +distribution of magnetism in our planet with relation to its intensity and +direction, but does not enter into a consideration of the laws of attraction +or repulsion of the poles, or the means of eliciting either permanent or +transitory electro-magnetic currents. Physical geography depicts in broad +outlines the even or irregular configuration of continents, the relations of +superficial area, and the distribution of continental masses in the two +hemispheres, a distribution which exercises a powerful influence on the +diversity of climate and the meteorological modifications of the atmosphere; +this science defines the character of mountain chains, which, having been +elevated at different epochs, constitute distinct systems, whether they run +in parallel lines or intersect one another; determines the mean height of +continents above the level of the sea, the position of the center of gravity +of their volume, and the relation of the highest summits of mountain chains +to the mean elevation of their crests, or to their proximity with the +sea-shore. It depicts the eruptive rocks as principles of movement, acting +upon the sedimentary rocks by traversing, uplifting, and inclining them at +various angles; it +p 60 +considers volcanoes either as isolated, or ranged in single or in double +series, and extending their sphere of action to various distances, either by +raising long and narrow lines of rocks, or by means of circles of commotion, +which expand or diminish in diameter in the course of ages. This +terrestrial portion of the science of the Cosmos describes the strife of the +liquid element with the solid land; it indicates the features possessed in +common by all great rivers in the upper and lower portion of their course, +and in their mode of bifurcation when their basins are unclosed; and shows +us rivers breaking through the highest mountain chains, or following for a +long time a course parallel to them, either at their base, or at a +considerable distance, where the elevation of the strata of the mountain +system and the direction of their inclination correspond to the +configuration of the table-land. It is only the general results of +comparative orography and hydrography that belong to the science whose true +limits I am desirous of determining, and not the special enumeration of the +greatest elevations of our globe, of active volcanoes, of rivers, and the +number of their tributaries, these details falliing rather within the domain +of geography, properly so called. We would here only consider phenomena in +their mutual connection, and in their relations to different zones of our +planet, and to its physical constitution generally. The specialties both of +inorganic and organized matter, classed according to analogy of form and +composition, undoubtedly constitute a most interesting branch of study, but +they appertain to a sphere of ideas having no affinity with the subject of +this work. + +The description of different countries certainly furnishes us with the most +important materials for the composition of a physical geography; but the +combination of these different descriptions, ranged in series, would as +little give us a true image of the general conformation of the irregular +surface of our globe, as a succession of all the floras of different regions +would constitute that which I designate as a 'Geography of Plants.' It is +by subjecting isolated observations to the process of thought, and by +combining and comparing them, that we are enabled to discover the relations +existing in common between the climatic distribution of beings and the +individuality of organic forms (in the morphology or descriptive natural +history of plants and animals); and it is by induction that we are led to +comprehend numerical laws, the proportion of natural families to the whole +number of species, and to designate the latitude or geographical position of +the zones in whose +p 61 +plains each organic form attains the maximum of its development. +Considerations of this nature, by their tendency to generalization, impress +a nobler character on the physical description of the globe, and enable us +to understand how the aspect of the scenery, that is to say, the impression +produced upon the mind by the physiognomy of the vegetation, depends upon +the local distribution, the number, and the luxuriance of growth of the +vegetable forms predominating in the general mass. The catalogues of +organized beings to which was formerly given the pompous title of 'Systems +of Nature', present us with an admirably connected arrangement by analogies +of structure, either in the perfected development of these beings, or in the +different phases which, in accordance with the views of a spiral evolution, +affect in vegetables the leaves, bracts, calyx, corolla and fructifying +organs; and in animals, with more or less symmetrical regularity, the +cellular and fibrous tissues, and their perfect or but obscurely developed +articulations. But these pretended systems of nature, however ingenious +their mode of classification may be, do not show us organic beings as they +are distributed in groups throughout our planet, according to their +different relations of latitude and elevation above the level of the sea, +and to climatic influences, which are owing to general and often very remote +causes. The ultimate aim of physical geography is, however, as we have +already said, to recognise unity in the vast diversity of phenomena, and by +the exercise of thought and the combination of observations, to discern the +constancy of phenomena in the midst of apparent changes. In the exposition +of the terrestrial portion of the Cosmos, it will occasionally be necessary +to descend to very special facts; but this will only be in order to recall +the connection existing between the actual distribution of organic beings +over the globe, and the laws of the ideal classification by natural +families, analogy of internal organization and progressive evolution. + +It follows from these discussions on the limits of the various sciences, and +more particularly from the distinction which must necessarily be made +between descriptive botany (morphology of vegetables) and the geography of +plants, that in the physical history of the globe, the innumerable multitude +of organized bodies which embellish creation are considered rather according +to 'zones of habitation' or 'stations', and to differently inflected +'isothermal bands', than with reference to the principles of gradation in +the development of internal organism. Notwithstanding this, botany and +zoology, which constitute +p 62 +the descriptive natural history of all organized beings, are the fruitful +sources whence we draw the materials necessary to give a solid basis to the +study of the mutual relations and connection of phenomena. + +We will here subjoin one important observation by way of elucidating the +connection of which we have spoken. The first general glance over the +vegetation of a vast extent of a continent shows us forms the most +dissimilar -- Graminae and Orchideae, Coniferae and oaks, in local +approximation to one another; while natural families and genera, instead of +being locally associated, are dispersed as if by chance. This dispersion +is, however, only apparent. The physical description of the globe teaches +us that vegetation every where presents numerically constant relations in +the development of its forms and types; that in the same climates, the +species which are wanting in one country are replaced in a neighboring one +by other species of the same family; and that this 'law of substitution', +which seems to depend upon some inherent mysteries of the organism, +considered with reference to its origin, maintains in contiguous regions a +numerical relation between the species of various great families and the +general mass of the phanerogamic plants constituting the two floras. We +thus revealed in the multiplicity of the distinct organizations by which +these regions are occupied; and we also discover in each zone, and +diversified according to the families of plants, a slow but continuous +action on the aerial ocean, depending upon the influence of light -- the +primary condition of all organic vitality -- on the solid and liquid surface +of our planet. It might be said, in accordance with a beautiful expression +of Lavoisier, that the ancient marvel of the myth of Prometheus was +incessantly renewed before our eyes. + +If we extend the course which we have proposed, following in the exposition +of the physical description of the earth to the sidereal part of the science +of the Cosmos, the delineation of the regions of space and the bodies by +which they are occupied, we shall find our task simplified in no common +degree. If, according to ancient but unphilosophical forms of nomenclature, +we would distinguish between 'physics', that is to say, general +considerations on the essence of matter, and the forces by which it is +actuated, and 'chemistry', which treats of the nature of substances, their +elementary composition, and those attractions that are not determined solely +by the relations of mass, we must admit that the description of the earth +comprises at +p 63 +once 'physical' and 'chemical' actions. In addition to gravitation, which +must be considered as a primitive force in nature, we observe that +attractions of another kind are at work around us, both in the interior of +our planet and on its surface. These forces, to which we apply the term +'chemical affinity', act upon molecules in contact, or at infinitely minute +distances from one another,* and which, being differently modified by +electricity, heat, condensation in porous bodies, or by the contact of an +intermediate substance, animate equally the inorganic world and animal and +vegetable tissues. + + +[footnote] * On the question already discussed by Newton, regarding the +difference existing between the attraction of masses and molecular +attraction, see Laplace, 'Exposition du Systeme du Monde', p. 384, and +supplement to book x. of the 'Mecanique Celeste', p. 3, 4; Kant, 'Metaph. +Anfangegrunde der Naturwissenschaft, Säm. Werke', 1839, bd. v., s. 309 +(Metaphysical Principles of the Natural Sciences); Pectet, 'Physique', 1838, +vol. i., p. 59-63. + + +If we except the small asteroids, which appear to us under the forms of +aerolites and shooting stars, the regions of space have hitherto presented +to our direct observation physical phenomena alone; and in the case of +these, we know only with certainty the effects depending upon the +quantitative relations of matter of the distribution of masses. The +phenomena of the regions of space may consequently be considered as +influenced by simple dynamical laws -- the laws of motion. + +The effects that may arise from the specific difference and the +hererogeneous nature of matter have not hitherto entered into our +calculations of the mechanism of the heavens. The only means by which the +inhabitants of our planet can enter into relation with the matter contained +within the regions of space, whether existing in scattered forms or united +into large spheroids, is by the phenomena of light, the propagation of the +force of gravitation or the attraction of masses. The existence of a +periodical action of the sun and moon on the variations of terrestrial +magnetism is even at the present day extremely problematical. We have no +direct experimental knowledge regarding the properties and specific +qualities of the masses circulating in space, or of the matter of which they +are probably composed, if we except what may be derived from the fall of +aerolites or meteoric stones, which, as we have already observed, enter +within the limits of our terrestrial sphere. It will be sufficient here to +remark, that the direction and the excessive velocity of projection (a +velocity wholly planetary) manifested by these masses, render it more than +probable that +p 64 +they are small celestial bodies, which, being attracted by our planet, are +made to deviate from their original course, and thus reach the earth +enveloped in vapors, and in a high state of actual incandescence. The +familiar aspect of these asteroids, and the analogies which they present +with the minerals composing the earth's crust, undoubtedly afford ample +grounds for surprise,* but, in my opinion, the only conclusion to be drawn +from these facts is that, in general, planets and other sidereal masses, +which by the influence of a central body, have been agglomerated into rings +of vapor, and subsequently into spheroids, being integrant parts of the same +system, and having one common origin, may likewise be composed of substances +chemically identical. + + +[footnote] I[The analysis of an aerolite which fell a few years since in +Maryland, United States, and was examined by Professor Silliman, of New +Haven, Connecticut, gave the following results: Oxyd of iron, 24; oxyd of +nickel, 1.25; silica, with earthy matter, 3.46; sulphur, a trace - 28.71. +Dr. Mantell's 'Wonders of Geology', 1848, vol. i., p. 51.] -- 'Tr.' + + +Again, experiments with the pendulum, particularly those prosecuted with +such rare precision by Bessel, confirm the Newtonian axiom, that bodies the +most heterogeneous in their nature (as water, gold, quartz, granular +limestone, and different masses of aerolites) experience a perfectly similar +degree of acceleration from the attraction of the earth. To the experiments +of the pendulum may be added the proofs furnished by purely astronomical +observations. The almost perfect identity of the mass of Jupiter, deduced +from the influence exercised by this stupendous planet on its own +satellites, on Enck's comet of short period, and on the small planets Vesta, +Juno, Ceres, and Pallas, indicates with equal certainty that within the +limits of actual observation attraction is determined solely by the quantity +of matter.* + + +[footnote] *Poisson, 'Connaissances des Temps pour l'Anne' 1836, p. 64-66. +Bessel, Poggendorf's 'Annalen', bd. xxv., s. 417. Encke, 'Abhandlungen der +Berliner Academie' (Trans. of the Berlin Academy), 1826, s. 257. +Mitscherlich, 'Lehrbuch der Chemie' (Manual of Chemistry), 1837 bd. i. s. +352. + + +This absence of any perceptible difference in the nature of matter, alike +proved by direct observation and theoretical deductions, imparts a high +degree of simplicity to the mechanism of the heavens. The immeasurable +extent of the regions of space being subjected to laws of motion alone, the +sidereal portion of the science of the Cosmos is based on the pure and +abundant source of mathematical astronomy, as is the terrestrial portion on +physics, chemistry, and organic morphology; but the domain of these three +last-named sciences embraces +p 65 +the consideration of phenomena which are so complicated and have, up to the +present time, been found so little susceptible of the application of +rigorous method, that the physical science of the earth can not boast of the +same certainty and simplicity in the exposition of facts and their mutual +connection which characterize the celestial portion of the Cosmos. It is +not improbable that the difference to which we allude may furnish an +explanation of the cause which, in the earliest ages of intellectual culture +among the Greeks, directed the natural philosophy of the Pythagoreans with +more ardor to the heavenly bodies and the regions of space than to the earth +and its productions, and how through Philolaus, and subsequently through the +analogous views of Aristarchus of Samos, and of Seleucus of Erythrea, this +science has been made more conducive to the attainment of a knowledge of the +true system of the world than the natural philosophy of the Ionian school +could ever be to the physical history of the earth. Giving but little +attention to the properties and specific differences of matter filling +space, the great Italian school, in its Doric gravity, turned by preference +toward all that relates to measure, to the form of bodies, and to the number +and distances of the planets,* while the Ionian physicists directed their +attention to the qualities of matter, its true or supposed metamorphoses, +and to relations of origin. + + +[footnote] *Compare Otfried Muller's 'Dorien', bd. i., s. 365. + + +It was reserved for the powerful genius of Aristotle, alike profoundly +speculative and practical to sound with equal success the depths of +abstraction and the inexhaustible resources of vital activity pervading the +material world. + +Several highly distinguished treatises on physical geography are prefaced by +an introduction, whose purely astronomical sections are directed to the +consideration of the earth in its planetary dependence, and as constituting +a part of that great system which is animated by one central body, the sun. +This course is diametrically opposed to the one which I propose following. +In order adequately to estimate the dignity of the Cosmos, it is requisite +that the sidereal portion, termed by Kant the 'natural history of the +heavens', should not be made subordinate to the terrestrial. In the science +of the Cosmos, according to the expression of Aristarchus of Samos, the +pioneer of the Copernican system, the sun, with its satellites, was nothing +more than one of the innumerable stars by which space is occupied. The +physical history of the world must, therefore, begin with the description of +the heavenly bodies, +p 66 +and with a geographical sketch of the universe, or, I would rather say, a +true 'map of th world', such as was traced by the bold hand of the elder +Herschel. If, notwithstanding the smallness of our planet, the most +considerable space and the most attentive consideration be here afforded to +that which exclusively concerns it, this arises solely from the +disproportion in the extent of our knowledge of that which is accessible and +of that which is closed to our observation. This subordination of the +celestial to the terrestrial portion is met with in the great work of +Bernard Varenius,* which appeared in the middle of the seventeenth century. + + +[Footnote] *'Geographia Generalis in qua affectiones generales telluris +explicantur.' The oldest Elzevir edition bears date 1650, the second 1672, +and the third 1681; these were published at Cambridge, under Newton's +supervision. This excellent work by Varenius is, in the true sense of the +words, a physical description of the earth. Since the work 'Historia +Natural de las Indias', 1590, in which the Jesuit Joseph de Acosta sketched +in so masterly a manner the delineation of the New Continent, questions +relating to the physical history of the earth have never been considered +with such admirable generality. Acosta is richer in original observations, +while Varenius embraces a wider circle of ideas, since his sojourn in +Holland, which was at that period the center of vast commercial relations, +had brought him in contact with a great number of well-iinformed travelers. +'Generalis sive Universalis Geographia dictur quae tellurem in genere +considerat atque affectiones explicat, non habita particularium regionum +ratione.' The general description of the earth by Varenius ('Pars +Absoluta', cap. i.-xxii.) may be considered as a treatise of comparative +geography, if we adopt the term used by the author himself ('Geographia +Comparativa', cap. xxxiii.-xl.), although this must be understood in a +limited acceptation. We may cite the following among the most remarkable +passages of this book: the enumeration of the systems of mountains; the +examination of the relations existing between their directions and the +general form of continents (p. 66, 76, ed. Cantab., 1681); a list of extinct +volcanoes, and such as were still in a state of activity; the discussion of +facts relative to the general distribution of islands and archipelagoes (p. +220); the depth of the ocean relatively to the height of neighboring coasts +(p. 103); the uniformity of level observed in all open seas (p. 97); the +dependence of currents on the prevailing winds; the unequal saltness of the +sea; the configuration of shores (p. 139); the direction of the winds as the +result of differences of temperature, etc. We may further instance the +remarkable considerations of Varenius regarding the equinoctial current from +east to west, to which he attributes the origin of the Gulf Stream, +beginning at Cape St. Augustin, and issuing forth between Cuba and Florida +(p. 140). Nothing can be more accurate than his description of the current +which skirts the western coast of Africa, between Cape Verde and the island +of Fernando Po in the Gulf of Guinea. Varenius explains the formation of +sporadic islands by supposing them to be "the raised bottom of the sea:" +'magna spirituum inclusorum vi, sicut aliquando montes e terra protusos esse +quidam scribunt' (p. 225). The edition published by Newton in 1681 +('auctior et emendatior' unfortunately contains no additions from this great +authority; and there is not even mention made of the polar compression of +the globe, although the experiments on the pendulum by Richer had been made +nine years prior to the appearance of the Cambridge edition. Newton's +'Principia Mathematica Philosophie Naturalis' were not communicated in +manuscript to the Royal Society until April, 1686. Much uncertainty seems +to prevail regarding the birth-place of Varenius. Jaecher says it was +England, while, according to 'La Biographie Universelle' (b.xlvii., p. 495), +he is stated to have been born at Amsterdam; but it would appear, from the +dedicatory address to the burgomaster of that city (see his 'Geographia +Comparativa', that both suppositions are false. Varenius expressly says +that he had sought refuge in Amsterdam, "because his native city had been +burned and completely destroyed during a long war," words which appear to +apply to the north of Germany, and to the devastations of the Thirty Years' +War. In his dedication of another work, 'Descriptio regni Japoniae' (Amst., +1649), to the Senate of Hamburgh, Varenius says that he prosecuted his +elementary mathematical studies in the gymnasium of that city. There is, +therefore, every reason to believe that this admirable geographer was a +native of Germany, and was probably born at Luneburg ('Witten. Mem. Theol.', +1685, p. 2142; Zedler, 'Universal Lexicon', vol. xlvi., 1745, p. 187). + +p 67 +He was the first to distinguish between 'general and special geography', the +former of which he subdivides into an 'absolute', or, properly speaking, +'terrestrial' part, and a 'relative or planetary' portion, according to the +mode of considering our planet either with reference to its surface in its +different zones, or to its relations to the sun and moon. It redounds to +the glory of Varenius that his work on 'General and Comparative Geography' +should in so high a degree have arrested the attention of Newton. The +imperfect state of many of the auxiliary sciences from which this writer was +obliged to draw his materials prevented his work from corresponding to the +greatness of the design, and it was reserved for the present age, and for my +own country, to see the delineation of comparative geography, drawn in its +full extent, and in all its relations with the history of man, by the +skillful hand of Carl Ritter.* + + +[Footnote] *Carl Ritter's 'Erdkunde im Verhältniss zur Natur und zur +Geschichte des Menschen, oder allgemeine vergleichende Geographie' +(Geography in relation to Nature and the History of Man, or general +Comparative Geography). + + +The enumeration of the most important results of the astronomical and +physical sciences which in the history of the Cosmos radiate toward one +common focus, may perhaps, to a certain degree, justify the designation I +have given to my work, and, considered within the circumscribed limits I +have proposed to myself, the undertaking may be esteemed less adventurous +than the title. The introduction of new terms, especially with reference to +the general results of a science which +p 68 +ought to be accessible to all, has always been greatly in opposition to my +own practice; and whenever I have enlarged upon the established +nomenclature, it has only been in the specialities of descriptive botany and +zoology, where the introduction of hitherto unknown objects rendered new +names necessary. The denominations of physical descriptions of the +universe, or physical cosmography, which I use indiscriminantely, have been +modeled upon those of 'physical descriptions of the earth', that is to say, +'physical geography', terms that have long been in common use. Descartes, +whose genius was one of the most powerful manifested in any age, has left us +a few fragments of a great work, which he intended publishing under the +title of 'Monde', and for which he had prepared hiimself by special studies, +including even that of human anatomy. The uncommon, but definite expression +of the 'science of the Cosmos' recalls to the mind of the inhabitant of the +earth that we are treating of a more widely-extended horizon -- of the +assemblage of all things with which space is filled, from the remotest +nebulae to the climatic distribution of those delicate tissues of vegetable +matter which spread a variegated covering over the surface of our rocks. + +The influence of narrow-minded views peculiar to the earlier ages of +civilization led in all languages to a confusion of ideas in the synonymic +use of the words 'earth' and 'world', while the common expressions 'voyages +round the world', 'map of the world', and 'new world', afford further +illustrations of the same confusion. The more noble and precisely-defined +expressions of 'system of the world', 'the planetary world', and 'creation +and age of the world', relate either to the totality of the substances by +which space is filled, or to the origin of the whole universe. + +It was natural that, in the midst of the extreme variability of phenomena +presented by the surface of our globe, and the aerial ocean by which it is +surrounded, man should have been impressed by the aspect of the vault of +heaven, and the uniform and regular movements of the sun and planets. Thus +the word Cosmos, which primitively, in the Homeric ages, indicated an idea +of order and harmony, was subsequently adopted in scientific language, where +it was gradually applied to the order observed in the movements of the +heavenly bodies, to the whole universe, and then finally to the world in +which this harmony was reflected to us. According to the assertion of +Philolaus, whose fragmentary works have been so ably commented upon by +Böckh, and conformably to the general testimony +p 69 +of antiquity, Pythagoras was the first who used the word Cosmos to designate +the order that reigns in the universe, or entire world.* + + +[footnote] *[Greek word], in the most ancient, and at the same time most +precise, definition of the word, signified 'ornament' (as an adornment for a +man, a woman, or a horse); taken figuratively for [Greek word], it implied +the order or adornment of a discourse. According to the testimony of all +the ancients, it was Pythagoras who first used the word to designate the +order in the universe, and the universe itself. Pythagoras left no +writings; but ancient attestation to the truth of this assertion is to be +found in several passages of the fragmentary works of Philolaus (Stob., +'Eclog.', p. 360 and 460, Heeren), p. 62, 90, in Bockh's German edition. I +do not, according to the example of Nake, cite Timof Locris, since his +authenticity is doubtful. Plutarch ('De plac. Phil.', ii., I) says, in the +most express manner, that Pythatoras gave the name of Cosmos to the universe +on account of the order which reigned throughout it; so likewise does Galen +('Hist. Phil.', p. 429). This word, together with its novel signification, +passed from the schools of philosophy into the language of poets and prose +writers. Plato designates the heavenly bodies by the name of 'Uranos', but +the order pervading the regions of space he too terms the Cosmos, and in his +'Timus' (p. 30 a.) he says 'that the world is an animal endowed with a soul' + [Greek words]. Compare Anaxag. Claz., ed. Schaubach, p. III, and Plut. +('De plac. Phil.', in Aristotle ('De Caelo', I, 9), 'Cosmos' signifies "the +universe and the order pervading it," but it is likewise considered as +divided in space into two parts -- the sublunary world, and the world above +the moon. ('Meteor.', I., w, 1, and I., 3, 13, p. 339, 'a', and 340, 'b', +Bekk.) The definition of Cosmos, which I have already cited is taken from +Pseudo-Aristoteles 'de Mundo', cap. ii. (p. 391); the passage referred to is +as follows: [Greek words]. Most of the passages occurring in Greek writers +on the word 'Cosmos' may be found collected together in the controversy +between Richard Bentley and Charles Boyle ('Opuscula Philologica', 1781, p. +347, 445; 'Dissertation upon the Epistles of Phalaris', 1817, p. 254); on +the historical existence of Zaleucus, legislator of Leucris, in Nake's +excellent work, 'Sched. Crit.', 1812, p. 9, 15; and, finally in Theophilus +Schmidt, 'ad Cleom. Cycl. Theor.', met. I., 1, p. ix., 1 and 99. Taken in a +more limited sense, the word Cosmos is also used in the plural (Plut., 1, +5), either to designate the stars (Stob., 1, p. 514; Plut., 11, 13) or the +innumerable systems scattered like islands through the immensity of space, +and each composed of a sun and a moon. (Anax. Claz., 'Fragm.', p. 89, 93, +120; Brandis, 'Gesch. der Griechisch-Römischen Philosophie', b. i., s. 252 +(History of the Greco-Roman Philosophy). Each of these groups forming thus +a 'Cosmos', the universe, [Greek words], the word must be understood in a +wider sense (Plut., ii., 1). It was not until long after the time of the +Ptolemies that the word was applied to the earth. Bockh has made known +inscriptions in praise of Trajan and Adrian ('Corpus Inscr. Graec.', I, n. +334 and 1036), in which [Greek word] occurs for [Greek word] in the same +manner as we still use the term 'world' to signify the earth alone. We have +already mentioned the singular division of the regions of space +p 70 [Footnote continues] +into three parts, the 'Olympus, Cosmos' and 'Ouranos' (Stob., i., p. 488; +Philolaus, p. 95, 303); this division applies to the different regions +surrounding that mysterious focus of the universe, the [Greek words] of the +Pythagoreans. In the fragmentary passage in which this division is found, +the term [Greek word] designates the innermost region, situated between the +moon and earth; this is the domain of changing things. The middle region, +where the planets circulate in an invariable and harmonious order, is, in +accordance with the special conceptions entertained of the universe, +exclusively termed 'Cosmos', while the word 'Olympus' is used to express the +exterior or igneous region. Bopp, the profound philologist, has remarked +that we may deduce, as Pott has done, 'Etymol. Forschungen', th.i., s. 39 +and 252 ('Etymol. Researches'), the word [Greek word] from the Sanscrit +root 'sud', 'purificari', by assuming two conditions; first that the Greek +letter 'kappa' in [Greek word] comes from the palatial 'epsilon', which Bopp +represents by 's' and Pott by 'ç' (in the same manner as [Greek word], +'decem, taihun' in Gothic, comes from the Indian word 'dasan'), and, next, +that the Indian 'd'' corresponds, as a general rule, with the Greek 'theta' +('Vergleichende Grammatik' 99 -- Comparative Grammar), which shows the +relation of [Greek word] (for [Greek word]) with the Sanscrit root 'sud', +whence is also derived [Greek word]. Another Indian term for the world is +'gagat' (pronounced 'dschagat'), which is, properly speaking the present +participle of the verb 'gagami' (I go), the root of which is 'ga.' In +restricting ourselves to the circle of Hellenic etymologies, we find +('Etymol. M.', p. 532, 12) that [Greek word] is intimately associated with +[Greek word] or rather with [Greek word], whence we have [Greek word] or +[Greek word] Welcker ('Eine Kretische Col in Theben', s. 23 -- A Cretan +Colony in Thebes) combines with this the name [Greek word] , as in Hesychius +[Greek word] signifies a Cretan suit of arms. When the scientific language +of Greece was introduced among the Romans, the word 'mundus', which at first +had only the primary meaning of [Greek word] (female ornament), was applied +to designate the entire universe. Ennius seems to have been the first who +ventured upon this innovation. In one of the fragments of this poet, +preserved by Macrobius, on the occasion of his quarrel with Virgil, we find +the word used in its novel mode of acceptation: "Mundus caeli vastus +constitit silentio" (Sat., vi., 2). Cicero also says, "Quem nos lucentem +mundum vocamus" (Timæus, 'S.de univer.', cap. x.) The Sanscrit root 'mand' +from which Pott derives the Latin 'mundus' ('Etym. Forsch.', th. i., s. +240), combines the double signification of shining and adorning. 'Loka' +designates in Sanscrit the world and people in general, in the same manner +as the French word 'monde', and is derived according to Bopp, from 'lok' (to +see and shine); it is the same with the Slavonic root 'swjet', which means +both 'light' and 'world.' (Grimm, 'Deutsche Gramm.', b. iii., s. 394 -- +German Grammar.) The word 'welt', which the Germans make use of at the +present day, and which was 'weralt' in old German, 'worold' in old Saxon, +and 'weruld' in Anglo-Saxon, was, according to James Grimm's interpretation, +a period of time, an age ('saeculum') rather than a term used for the world +in space. The Etruscans figured to themselves 'mundus' as an inverted dome, +symmetrically opposed to the celestial vault (Otfried Muller's 'Etrusken', +th. ii., s. 96, etc.). Taken in a still more limited sense, the word +appears to have signified among the Goths the terrestrial surface girded by +seas ('marei, meri',) the 'merigard', literally, 'garden of seas.' + + +From the Italian school of philosophy, the expression passed, in this +signification, into the language of those early poets +p 71 +of nature, Parmenides and Empedocles, and from thence into the works of +prose writers. We will not here enter into a discussion of the manner in +which, according to the Pythagorean views, Philolaus distinguishes between +Olympus, Uranus, or the heavens, and Cosmos, or how the same word, used in a +plural sense, could be applied to certain heavenly bodies (the planets) +revolving round one central focus of the world, or to groups of stars. In +this work I use the word Cosmos in conformity with the Hellenic usage of the +term subsequently to the time of Pythagorus, and in accordance with the +precise definition given of it in the treatise entitled 'De Mundo', which +was long erroneously attributed to Aristotle. It is the assemblage of all +things in heaven and earth, the universality of created things constituting +the perceptible world. If scientific terms had not long been diverted from +their true verbal signification, the present work ought rather to have borne +the title of 'Cosmography', divided into 'Uranography' and 'Geography.' The +Romans, in their feeble essays on philosophy, imitated the Greeks by +applying to the universe the term 'mundus', which, in its primary meaning, +indicated nothing more than ornament, and did not even imply order or +regularity in the disposition of parts. It is probable that the +introduction into the language of Latium of this technical term as an +equivalent for Cosmos, in its double signification, is due to Ennius,* who +was a follower of the Italian school, and the translator of the writings of +Epicharmus and some of his pupils on the Pythagorean philosophy. + + +[footnote] *See, on Ennius, the ingenious researches of Leopold Krahner, in +his 'Grundlinien zur Geschichte des Verfalls der Romischen Staats-Reigion', +1837, s. 41-45 (Outlines of the History of the Decay of the Established +Religion among the Romans). In all probability, Ennius did not quote from +writings of Epicharmus himself, but from poems composed in the name of that +philosopher, and in accordance with his views. + + +We would first distinguish between the physical 'history' and the physical +'description' of the world. The former, conceived in the most general sense +of the word, ought, if materials for writing it existed, to trace the +variations experienced by the universe in the course of ages from the new +stars which have suddenly appeared and disappeared in the vault of heaven, +from nebulæ dissolving or condensing -- to the first stratum of cryptogamic +vegetation on the still imperfectly cooled surface of the earth, or on a +reef of coral uplifted from the depths of ocean. 'The physical description +of the world' presents a picture of all that exists in space -- of the +siimultaneous action of +p 72 +natural forces, together with the phenomena which they produce. + +But if we would correctly comprehend nature, we must not entirely or +absolutely separate the consideration of the present state of things from +that of the successive phases through which they have passed. We can not +form a just conception of their nature without looking back on the mode of +their formation. It is not organic matter alone that is continually +undergoing change, and being dissolved to form new combinations. The globe +itself reveals at every phase of its existence the mystery of its former +conditions. + +We can not survey the crust of our planet without recognizing the traces of +the prior existence and destruction of an organic world. The sedimentary +rocks present a succession of organic forms, associated in groups, which +have successively displaced and succeeded each other. The different +super-imposed strata thus display to us the faunas and floras of different +epochs. In this sense the description of nature is intimately connected +with its history; and the geologist, who is guided by the connection +existing among the facts observed, can not form a conception of the present +without pursuing, through countless ages, the history of the past. In +tracing the physical delineation of the globe, we behold the present and the +past reciprocally incorporated, as it were, with one another; for the domain +of nature is like that of languages, in which etymological research reveals +a successive development, by showing us the primary condition of an idiom +reflected in the forms of speech in use at the present day. The study of +the material world renders this reflection of the past peculiarly manifest, +by displaying in the process of formation rocks of eruption and sedimentary +strata similar to those of former ages. If I may be allowed to borrow a +striking illustration from the geological relations by which the physiognomy +of a country is determined, I would say that domes of trachyte, cones of +basalt, lava streams ('coules')of amygdaloid with elongated and parallel +pores, and white deposits of pumice, intermixed with black scoriae, animate +the scenery by the associations of the past which they awaken, acting upon +the imagination of the enlightened observer like traditional records of an +earlier world. Their form is their history. + +The sense in which the Greeks and Romans originally employed the word +'history' proves that they too were intimately convinced that, to form a +complete idea of the present state of the universe, it was necessary to +consider it in its successive +p 73 +phases. It is not, however, in the definition given by Valerius Flaccus,* +but in the zoological writings of Aristotle, that the word 'history' +presents itself as an exposition of the results of experience and +observation. + + +[Footnote] *Aul. Gell., 'Nect. Att.', v., 18. + + +The physical description of the word by Pliny the elder bears the title of +'Natural History', while in the letters of his nephew it is designated by +the nobler term of 'History of Nature.' The earlier Greek historians did +not separate the description of countries from the narrative of events of +which they had been the theater. With these writers, physical geography and +history were long intimately associated, and remained simply but elegantly +blended until the period of the development of political interests, when the +agitation in which the lives of men were passed caused the geographical +portion to be banished from the history of nations, and raised into an +independent science. + +It remains to be considered whether by the operation of thought, we may hope +to reduce the immense diversity of phenomena comprised by the Cosmos to the +unity of a principle, and the evidence afforded by rational truths. In the +present state of empirical knowledge, we can scarcely flatter ourselves with +such a hope. Experimental sciences, based on the observation of the +external world, can not aspire to completeness; the nature of things, and +the imperfection of our organs, are alike opposed to it. We shall never +succeed in exhausting the immeasurable riches of nature; and no generation +of men will ever have cause to boast of having comprehended the total +aggregation of phenomena. It is only by distributing them into groups that +we have been able, in the case of a few, to discover the empire of certain +natural laws, grand and simple as nature itself. The extent of this empire +will no doubt increase in proportion as physical sciences are more perfectly +developed. Striking proofs of this advancement have been made manifest in +our own day, in the phenomena of electro-magnetism, the propagation of +luminous waves and radiating heat. In the same manner, the fruitful +doctrine of evolution shows us how, in organic development, all that is +formed is sketched out beforehand, and how the tissues of vegetable and +animal matter uniformly arise from the multiplication and transformation of +cells. + +The generalization of laws, which, being at first bounded by narrow limits, +had been applied solely to isolated groups of phenomena, acquires in time +more marked gradations, and gains in extent and certainty as long as the +process of reasoning +p 74 +is applied strictly to analogous phenomena; but as soon as dynamical views +prove insufficient where the specific properties and heterogeneous nature of +matter come into play; it is to be feared that, by persisting in the pursuit +of laws, we may find our course suddenly arrested by an impassible chasm. +The principle of unity is lost sight of, and the guiding clew is rent +asunder whenever any specific and peculiar kind of action manifests itself +amid the active forces of nature. The law of equivalents and the numerical +proportions of composition, so happily recognized by modern chemists, and +proclaimed under the ancient form of atomic symbols, still remains isolated +and independent of mathematicl laws of motion and gravitation. + +Those productions of nature which are objects of direct observation may be +logically distributed in classes, orders, and families. This form of +distribution undoubtedly sheds some light on descriptive natural history, +but the study of organized bodies, considered in their linear connection, +although it may impart a greater degree of unity and simplicity to the +distribution of groups, can not rise to the height of a classification based +on one sole principle of composition and internal organization. As +different gradations are presented by the laws of nature according to the +extent of the horizon, or the limits of the phenomena to be considered, so +there are likewise differently graduated phases in the investigation of the +external world. Empiricism originates in isolated views, which are +subsequently grouped according to their analogy or dissimilarity. To direct +observation succeeds, although long afterward, the wish to prosecute +experiments; that is to say, to evoke phenomena under different determined +conditions. The rational experimentalist does not proceed at hazard, but +acts under the guidance of hypotheses, founded on a half indistinct and more +or less just intuition of the connection existing among natural objects or +forces. That which has been conquered by observation or by means of +experiments, leads, by analysis and induction, to the discovery of empirical +laws. These are the phases in human intellect that have marked the +different epochs in the life of nations, and by means of which that great +mass of facts has been accumulated which constitutes at the present day the +solid basis of the natural sciences. + +Two forms of abstraction conjointly regulate our knowledge, namely, +relations of 'quantity', comprising ideas of number and size, and relations +of 'quality', embracing the consideration of the specific properties and the +heterogeneous nature +p 75 +of matter. The former, as being more accessible to the exercise of thought, +appertains to mathematics; the latter, from the apparent mysteries and +greater difficulties, falls under the domain of the chemical sciences. In +order to submit phenomena to calculation, recourse is had to a hypothetical +construction of matter by a combination of molecules and atoms, whose +number, form, position, and polarity determine, modify, or vary phenomena. + +The mythical ideas long entertained of the imponderable substances and vital +forces peculiar to each mode of organization, have complicated our views +generally, and shed an uncertain light on the path we ought to pursue. + +The most various forms of intuition have thus, age after age, aided in +augmenting the prodigious mass of empirical knowledge, which, in our own day +has been enlarged with ever-increasing rapidity. The investigating spirit +of man strives from time to time, with varying success, to break through +those ancient forms and symbols invented, to subject rebellious matter to +rules of mechanical construction. + +We are still very far from the time when it will be possible for us to +reduce, by the operation of thought, all that we perceive by the senses, to +the unity of a rational principle. It may even be doubted if such a victory +could ever be achieved in the field of natural philosophy. The complication +of phenomena, and of the vast extent of the Cosmos, would seem to oppose +such a result; but even a partial solution of the problem -- the tendency +toward a comprehension of the phenomena of the universe -- will not the less +remain the eternal and sublime aim of every investigation of nature. + +In conformity with the character of my former writings, as well as with the +labors in which I have been engaged during my scientific career, in +measurements, experiments, and the investigation of facts, I limit myself to +the domain of empirical ideas. + +The exposition of mutually connected facts does not exclude the +classification of phenomena according to their rational connection, the +generalization of many specialities in the great mass of observations, or +the attempt to discover laws. Conceptions of the universe solely based upon +reason, and the principles of speculative philosophy, would no doubt assign +a still more exalted aim to the science of the Cosmos. I am far from +blaming the efforts of others solely because their success has hitherto +remained very doubtful. Contrary to the wishes and counsel of of those +profound and powerful thinkers who +p 76 +have given new life to speculations which were already familiar to the +ancients, systems of natural philosophy have in our own country for some +time past turned aside the minds of men from the graver study of +mathematical and physical sciences. The abuse of better powers, which has +led many of our noble but ill-judging youth into the saturnalia of a purely +ideal science of nature, has been signalized by the intoxication of +pretended conquests, by a novel and fantastically symbolical phraseology, +and by a predilection for the formulae of a scholastic rationalism, more +contracted in its views than any known to the Middle Ages. I use the +expression "abuse of better powers," because superior intellects devoted to +philosophical pursuits and experimental sciences have remained strangers to +these saturnalia. The results yielded by an earnest investigation in the +path of experiment can not be at variance with a true philosophy of nature. +If there be any contradiction, the fault must lie either in the unsoundness +of speculation, or in the exaggerated pretensions of empiricism, which +thinks that more is proved by experiment than is actually derivable from it. + +External nature may be opposed to the intellectual world, as if the latter +were not comprised within the limits of the former, or nature may be opposed +to art when the latter is defined as a manifestation of the intellectual +power of man; but these contrasts, which we find reflected in the most +cultivated languages, must not lead us to separate the sphere of nature from +that of mind, since such a separation would reduce the physical science of +the world to a mere aggregation of empirical specialities. Science does not +present itself to man until mind conquers matter in striving to subject the +result of experimental investigation to rational combinations. Science is +the labor of mind applied to nature, but the external world has no real +existence for us beyond the image reflected within ourselves through the +medium of the senses. As intelligence and forms of speech, thought and its +verbal symbols, are united by secret and indissoluble links, so does the +external world blend almost unconsciously to ourselves with our ideas and +feelings. "External phenomena," says Hegel, in his 'Philosophy of History', +"are in some degree translated in our inner representations." The objective +world, conceived and reflected within us by thought, is subjected to the +eternal and necessary conditions of our intellectual being. The activity of +the mind exercises itself on the elements furnished to it by the perceptions +of the senses. Thus, in the +p 77 +early ages of mankind, there manifests itself in the simple intuition of +natural facts, and in the efforts made to comprehend them, the germ of the +philosophy of nature. These ideal tendencies vary, and are more or less +powerful, according to the individual characteristics and moral dispositions +of nations, and to the degrees of their mental culture, whether attained +amid scenes of nature that excite or chill the imagination. + +History has preserved the record of the numerous attempts that have been +made to form a rational conception of the whole world of phenomena, and to +recognize in the universe the action of one sole active force by which +matter is penetrated, transformed, and animated. These attempts are traced +in classical antiquity in those treatises on the principles of things which +emanated from the Ionian school, and in which all the phenomena of nature +were subjected to hazardous speculations, based upon a small number of +observations. By degrees, as the influence of great historical events has +favored the development of every branch of science supported by observation, +that ardor has cooled which formerly led men to seek the essential nature +and connection of things by ideal construction and in purely rational +principles. In recent times, the mathematical portion of natural philosophy +has been most remarkably and admirably enlarged. The method and the +instrument (analysis) have been simultaneously perfected. That which has +been acquired by means so different -- by the ingenious application of +atomic suppositions, by the more general and intimate study of phenomena, +and by the improved construction of new apparatus -- is the common property +of mankind, and shouldnot, in our opinion, now, more than in ancient times, +be withdrawn from the free exercise of speculative thought. + +It can not be denied that in this process of thought, the results of +experience have had to contend with many disadvantages; we must not, +therefore, be surprised if, in the perpetual vicissitude of theoretical +views, as is ingeniously expressed by the author of 'Giordano Bruno', "most +men see nothing in philosophy but a succession of passing meteors, while +even the grander forms in which she has revealed herself share the fate of +comets, bodies that do not rank in popular opinion among the eternal and +permanent works of nature, +p 78 +but are regarded as mere fugitive apparitions of igncor vapor." + + +[Footnote] *Schelling's Bruno, 'eber das Gottliche und Naturaliche Princip. +der Dinge', 181 (Bruno, on the 'Divine and Natural Principle of Things') + + +We would here remark that the abuse of thought, and the false track it too +often pursues, ought not to sanction an opinion derogatory to the intellect, +which would imply that the domain of mind is essentially a world of vague +fantastic illusions, and that the treasures accumulated by laborious +observations in philosophy are powers hostile to its own empire. It does +not become the spirit which characterizes the present age distrustfully to +reject every generalization of views and every attempt to examine into the +nature of things by the process of reason and induction. It would be a +denial of the dignity of human nature and the relative importance of the +faculties with which we are endowed, were we to condemn at one time austere +reason engaged in investigating causes and their natural connections, and at +another that exercise of the imagination which prompts and excites +discoveries by its creative powers. + +This material taken from pages 79 to 111 + + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p 79 + +COSMOS. + + +------------------------- + +DELINEATION OF NATURE. GENERAL REVIEW OF NATURAL PHENOMENA. + +WHEN the human mind first attempts to subject to its control the world of +physical phenomena, and strives by meditative contemplation to penetrate the +rich luxuriance of living nature, and the mingled web of free and restricted +natural forces, man feels himself raised to a height from whence, as he +embraces the vast horizon, individual things blend together in varied +groups, and appear as if shrouded in a vapory + vail. These figurative expressions are used in order to illustrate the +point of view from whence we would consider the universe both in its +celestial and terrestrial sphere. I am not insensible of the boldness of +such an undertaking. Among all the forms of exposition to which these pages +are devoted, there is none more difficult than the general delineation of +nature, which we purpose sketching, since we must not allow ourselves to be +overpowered by a sense of the stupendous richness and variety of the forms +presented to us, but must dwell only on the consideration of masses either +possessing actual magnitude, or borrowing its semblance from the +associations awakened within the subjective sphere of ideas. It is by a +separation and classification of phenomena by an intuitive insight into the +play of obscure forces, and by animated expressions, in which the +perceptible spectacle is reflected with vivid truthfulness, that we may hope +to comprehend and describe the 'universal all' [Greek words] in a manner +worthy of the dignity of the word 'Cosmos' in its signification of +'universe, order of the world', and 'adornment' of this universal order. +May the immeasurable diversity of phenomena which crowd into the picture of +nature in no way detract from that harmonious impression of rest and unity +which is the ultimate object of every literary or purely artistical +composition. + +Beginning with the depths of space and the regions of remotest nebulae, we +will gradually descend through the starry zone to which our solar system +belongs, to our own terrestrial spheroid, circled by air and ocean, there to +direct our attention +p 80 +to its form, temperature, and magnetic tension, and to consider the fullness +of organic life unfolding itself upon its surface beneath the vivifying +influence of light. In this manner a picture of the world may, with a few +strokes, be made to include the realms of infinity no less than the minute +microscopic animal and vegetable organisms which exist in standing waters +and on the weather-beaten surface of our rocks. All that can be perceived +by the senses, and all that has been accumulated up to the present day by an +attentive and variously directed study of nature, constitute the materials +from which this representation is to be drawn, whose character is an +evidence of its fidelity and truth. But the descriptive picture of nature +which we purpose drawing must not enter too fully into detail, since a +minute enumeration of all vital forms, natural objects, and processes is not +requisite to the completeness of the undertaking. The delineator of nature +must resist the tendency toward endless division, in order to avoid the +dangers presented by the very abundance of our empirical knowledge. A +considerable portion of the qualitative properties of matter -- or, to speak +more in accordance with the language of natural philosophy, of the +qualitative expression of forces -- is doubtlessly still unknown to us, and +the attempt perfectly to represent unity in diversity must therefore +necessarily prove unsuccessful. Thus, besides the pleasure derived and +tinged with a shade of sadness, an unsatisfied longing for something beyond +the present -- a striving toward regions yet unknown and unopened. Such a +sense of longing binds still faster the links which, in accordance with the +supreme laws of our being, connect the material with the ideal world, and +animates the mysterious relation existing between that which the mind +receives from without, and that which it reflects from its own depths to the +external world. If, then, nature (understanding by the term all natural +objects and phenomena) be illimitable in extent and contents, it likewise +presents itself to the human intellect as a problem which can not be +grasped, and whose solution is impossible, since it requires a knowledge of +the combined action of all natural forces. Such an acknowledgement is due +where the actual state and prospective development of phenomena constitute +the sole objects of direct investigation, which does not venture to depart +from the strict rules of induction. But, although the incessant effort to +embrace nature in its universality may remain unsatisfied, the history of +the contemplation of the universe (which +p 81 +will be considered in another part of this work) will teach us how, in the +course of ages, mankind has gradually attained to a partial insight into the +relative dependence of phenomena. My duty is to depict the results of our +knowledge in all their bearings with reference to the present. In all that +is subject to motion and change in space, the ultimate aim, the very +expression of physical laws, depend upon 'mean numerical values', which show +us the constant amid change, and the stable amid apparent fluctuations of +phenomena. Thus the progress of modern physical science is especially +characterized by the attainment and the rectification of the mean values of +certain quantities by means of the processes of weighing and measuring; and +it may be said, that the only remaining and widely-diffused hieroglyphic +characters still in our writing -- 'numbers' -- appear to us again, as +powers of the Cosmos, although in a wider sense than that applied to them by +the Italian School. + +The earnest investigator delights in the simplicity of numerical relations, +indicating the dimensions of the celestial regions, the magnitudes and +periodical disturbances of the heavenly bodies, the triple elements of +terrestrial magnetism, the mean pressure of the atmosphere, and the quantity +of heat which the sun imparts in each year, and in every season of the year, +to all points of the solid and liquid surface of our planet. These sources +of enjoyment do not, however, satisfy the poet of Nature, or the mind of the +inquiring many. To both of these the present state of science appears as a +blank, now that she answers doubtingly, or wholly rejects as unanswerable, +questions to which former ages deemed they could furnish satisfactory +replies. In her severer aspect, and clothed with less luxuriance, she shows +herself deprived of that seductive charm with which a dogmatizing and +symbolizing physical philosophy knew how to deceive the understanding and +give the rein to imagination. Long before the discovery of the New World, +it was believed that new lands in the Far West might be seen from the shores +of the Canaries and the Azores. These illusive images were owing, not to +any extraordinary refraction of the rays of light, but produced by an eager +longing for the distant and the unattained. The philosophy of the Greeks, +the physical views of the Middle Ages, and even those of a more recent +period, have been eminently imbued with the charm springing from similar +illusive phantoms of the imagination. At the limits of circumscribed +knowledge, as from some lofty island shore, the eye delights to penetrate +p 82 +to distant regions. The belief in the uncommon and the wonderful lends a +definite outline to every manifestation of ideal creation; and the realm of +fancy -- a fairy-land of cosmological, geognostical, and magnetic visions -- +becomes thus involuntarily blended with the domain of reality. + +Nature, in the manifold signification of the word -- whether considered as +the universality of all that is and ever will be -- as the inner moving +force of all phenomena, or as their mysterious prototype -- reveals itself +to the simple mind and feelings of man as something earthly, and closely +allied to himself. It is only within the animated circles of organic +structure that we feel ourselves peculiarly at home. Thus, wherever the +earth unfolds her fruits and flowers, and gives food to countless tribes of +animals, there the image of nature impresses itself most vividly upon our +senses. The impression thus produced upon our minds limits itself almost +exclusively to the reflection of the earthly. The starry vault and the wide +expanse of the heavens belong to a picture of the universe, in which the +magnitude of masses, the number of congregated suns and faintly glimmering +nebulae, although they excite our wonder and astonishment, manifest +themselves to us in apparent isolation, and as utterly devoid of all +evidence of their being the scenes of organic life. Thus, even in the +earliest physical views of mankind, heaven and earth have been separated and +opposed to one another as an upper and lower portion of space. If, then, a +picture of nature were to correspond to the requirements of contemplation by +the senses, it ought to begin with a delineation of our native earth. It +should depict, first, the terrestrial planet as to its size and form; its +increasing density and heat at increasing depths in its superimposed solid +and liquid strate; the separation of sea and land, and the vital forms +animating both, developed in the cellular tissues of plants and animals; the +atmospheric ocean, with its waves and currents, through which pierce the +forest-crowned summits of our mountain chains. After this delineation of +purely telluric relations, the eye would rise to the celestial regions, and +the Earth would then, as the well-known seat of organic development, be +considered as a planet, occupying a place in the series of those heavenly +bodies which circle round one of the innumerable host of self-luminous +stars. This succession of ideas indicates the course pursued in the +earliest stages of perceptive contemplation, and reminds us of the ancient +conception of the "sea-girt disk of earth," supporting the vault of heaven. +It begins to exercise in action +p 83 +at the spot where it originated, and passes from the consideration of the +known to the unknown, of the near to the distant. It corresponds with the +method pursued in our elementary works on astronomy (and which is so +admirable in a mathematical point of view), of proceeding from the apparent +to the real movements of the heavenly bodies. + +Another course of ideas must, however, be pursued in a work which proposes +merely to give an exposition of what is known -- of what may in the present +state of our knowledge be regarded as certain, or as merely probable in a +greater or lesser degree -- and does not enter into a consideration of the +proofs on which such results have been based. Here, therefore, we do not +proceed from the subjective point of view of human interests. The +terrestrial must be treated only as grand and free, uninfluenced by motives +of proximity, social sympathy, or relative utility. A physical cosmography +-- a picture of the universe -- does not begin, therefore, with the picture +of the universe -- does not begin, therefore, with the terrestrial, but with +that which fills the regions of space. But as the sphere of contemplation +contracts in dimension our perception of the richness of individual parts, +the fullness of physical phenomena, and of the heterogeneous properties of +matter becomes enlarged. From the regions in which we recognize ony the +dominion of the laws of attraction, we descend to our own planet, and to the +intricate play of terrestrial forces. The method here described for the +delineation of nature is opposed to that which mst be pursued in +establishing conclusive results. The one enumerates what the other +demonstrates. + +Man learns to know the external world through the organs of the senses. +Phenomena of light proclaim the existence of matter in remotest space, and +the eye is thus made the medium through which we may contemplate the +universe. The discovery of telescopic vision more than two centuries ago, +has transmitted to latest generations a power whose limits are as yet +unattained. + +The first and most general consideration of the Cosmos is that of the +'contents of space' -- the distribution of matter, or of creation, as we are +wont to designate the assemblage of all that is and ever will be developed. +We see matter either agglomerated into rotating, revolving spheres of +different density and size, or scattered through space in the form of +self-luminous vapor. If we consider first the cosmical vapor dispersed in +definite nebulous spots, its state of aggregation will +p 84 +appear constantly to vary, sometimes appearing separated into round or +elliptical disks, single or in pairs, occasionally connected by a thread of +light; while, at another time, these nebulae occur in forms of larger +dimensions, and are either elongated, or variously branched or fan-shaped or +appear like well-defined rings, including a dark interior. It is +conjectured that these bodies are undergoing variously developed formative +processes, as the cosmical vapor becomes condensed in conformity with the +laws of attraction, either round one or more of the nuclei. Between two and +three thousand of such unresolvable nebulae, in which the most powerful +telescopes have hitherto been unable to distinguish the presence of stars, +have been counted, and their positions determined. + +The genetic evolution -- that perpetual state of development which seems to +affect this portion of the regions of space -- has led philosophical +observers to the discovery of the analogy existing among organic phenomena. +As in our forests we see the same kind of tree in all the various stages of +its growth, and are thus enabled to form an idea of progressive, vital +development, so do we also in the great garden of the universe, recognise +the most different phases of sidereal formation. The process of +condensation, which formed a part of the doctrines of Anaximenes and of the +Ionian School, appears to be going on before our eyes. This subject of +investigation and conjecture is especially attractive to the imagination, +for in the study of the animated circles of nature, and of the action of all +the moving forces of the universe, the charm that exercises the most +powerful influence on the mind is derived less from a knowledge of that +which 'is' than from a perception of that which 'will be', even though the +latter be nothing more than a new condition of a known material existence; +for of actual creation, of origin, the beginning of existence from +non-existence, we have no experience, and can therefore form no conception. + +A comparison of the various causes influencing the development manifested by +the greater or less degree of condensation in the interior of nebulae, no +less than a successive course of direct observations, have led to the belief +that changes of form have been recognized first in Andromeda, next in the +constallation Argo, and in the isolated filamentous portion of the nebula in +Orion. But want of uniformity in the power of the instruments employed, +different conditions of our atmosphere, and other optical relations, render +a part of the results invalid as historical evidence. + +p 85 +'Nebulous stars' must not be confounded either with irregularly-shaped +nebulous spots, properly so called, whose separate parts have an unequal +degree of brightness (and which may, perhaps, become concentrated into stars +as their circumference contracts), nor with the so-called planetary nebulae, +whose circular or slightly oval disks manifest in all their parts a +perfectly uniform degree of faint light. 'Nebulous stars' are not merely +accidental bodies projected upon a nebulous ground, but are a part of the +nebulous matter constituting one mass with the body which it surrounds. The +not unfrequently considerable magnitude of their apparent diameter, and the +remote distance from which they are revealed to us, show that both the +planetary nebulae and the nebulous stars must be of enormous dimensions. +New and ingenious considerations of the different influence exercised by +distance* on the intensity of light of a disk of appreciable diameter, and +of a single self-luminous point, render it not improbable that the planetary +nebulae are very remote nebulous stars, in which the difference between the +central body and the surrounding nebulous covering can no longer be detected +by our telescopic instruments. + + +[footnote] * The optical considerations relative to the difference +presented by a single luminous point, and by a disk subtending an +appreciable angle, in which the intensity of light is constant at every +distance, are explained in Arago's 'Analyse des Travaux de Sir William +Herschel' ('Annuaire du Bureau des Long.', 1842, p. 410-412, and 441). + + +The magnificent zones of the southern heavens, between 50 degrees and 80 +degrees, are especially rich in nebulous stars, and in compressed +unresolvable nebua e. The larger of the two Magellanic clouds, which circle +round the starless, desert pole of the south, appears, according to the most +recent researches,* as "a collection of clusters of stars, composed of +globular clusters and nebulae of different magnitude, and of large nebulous +spots + +p 86 +not resolvable, which, producing a general brightness in the field of view, +form, as it were, the back-ground of the picture." + + +[footnote] *The two Magellanic clouds, Nubecula major and Nubecula minor, +are very remarkable objects. The larger of the two is an accumulated mass +of stars, and consists of clusters of stars of irregular form, either +conical masses or nebulae of different magnitudes and degrees of +condensation. This is interspersed with nebulous spots, not resolvable into +stars, but which are probably 'star dust', appearing only as a general +radiance upon the telescopic field of a twenty-feet reflector, and forming a +luminous ground on which other objects of striking and indescribable form +are scattered. In no other portion of the heavens are so many nebulous and +stellar masses thronged together in an equally small space. Nubecula minor +is much less beautiful, has more unresolvable nebulous light, while the +stellar masses are fewer and fainter in intensity. -- (From a letter of Sir +John Herschel, Feldhuysen, Cape of Good Hope, 13th June, 1836.) + + +The appearance of these clouds, of the brightly-beaming constellation Argo, +of the Milky Way between Scorpio, the Centaur, and the Southern Cross, the +picturesque beauty, if one may so speak, of the whole expanse of the +southern celestial hemisphere, has left upon my mind an ineffaceable +impression. The zodiacal light, which rises in a pyramidal form, and +constantly contributes, by its mild radiance, to the external beauty of the +tropical nights, is either a vast nebulous ring, rotating between the Earth +and Mars, or, less probably, the exterior stratum of the solar atmosphere. +Besides these luminous clouds and nebulae of definite form, exact and +corresponding observations indicate the existence and the general +distribution of an apparently non-luminous, infinitely-divided matter, which +posssesses a force of resistance and manifests its presence in Encke's, and +perhaps also in Biela's comet, by diminishing their eccentricity and +shortening their period of revolution. Of this impending, ethereal, and +cosmical matter, it may be supposed that it is in motion; that it +gravitates, notwithstanding its original tenuity; that it is condensed in +the vicinity of the great mass of the Sun; and, finally, that it may, for +myriads of ages, have been augmented by the vapor emanating from the tails +of comets. + +If we now pass from the consideration of the vaporous matter of the +immeasurable regions of space [(Greek)*] -- whether scattered without +definite form and limits, it exists as a cosmical other, or is condensed +into nebulous spots, and becomes comprised among the solid agglomerated +bodies of the universe -- we approach a class of phenomena exclusively +designated by the form of stars, or as the sidereal world. + + +[footnote] *I should have made use, in the place of garden of the universe, +of the beautiful expression [Greek], borrowed by Hesychius from an unknown +poet, if [Greek] had not rather signified in general an inclosed space. The +connection with the German 'garten' and the English 'garden', 'gards' in +Gothic (derived according to Jacob Grimm, from 'gairdan', 'to gird'), is, +however, evident, as is likewise the affinity with the Slavonic 'grad', +'gorod', and as Pott remarks, in his 'Etymol. Forschungen', th. i., s. 144 +(Etymol. Researches), with the Latin 'chors', whence we have the Spanish +'corte', the French 'cour', and the English word 'court', together with the +Ossetic 'khart'. To these may be further added the Scandinavian 'gard',** +'gard', a place inclosed, as a court, or a country seat, and the Persian +'gerd', 'gird', a district, a circle, a princely country seat, a castle or +city, as we find the term applied to the names of places in Firdusi's +Schahnameh, as 'Siyawakschgird', 'Darabgird', etc. + +** (This word is written 'gaard' in the Danish) -- Tr. + + +p 87 +Here, too, we find differences existing in the solidity or density of the +spheroidally agglomerated matter. Our own solar system presents all stages +of 'mean' density (or of the relation of 'volume' to 'mass'.) On comparing +the planets from Mercury to Mars with the Sun and with Jupiter, and these +two last named with the yet inferior density of Saturn, we arrive, by a +descending scale -- to draw our illustration from the terrestrial substances +-- at the respective densities of antimony, honey, water, and pine wood. In +comets, which actually constitute the most considerable portion of our solar +system with respect to the number of individual forms, the concentrated +part, usually termed the 'head', or 'nucleus', transmits sidereal light +unimpaired. The mass of a comet probably in no case equals the five +thousandth part of that of the earth, so dissimilar are the formative +processes manifested in the original and perhaps still progressive +agglomerations of matter. In proceeding from general to special +considerations, it was particularly desirable to draw attention to this +diversity, not merely as a possible, but as an actually proved fact. + +The purely speculative conclusions arrived at by Wright, Kant, and Lambert, +concerning the general structural arrangement of the universe, and of the +distribution of matter in space, have been confirmed by Sir William +Herschel, on the more certain path of observation and measurement. That +great and enthusiastic, although cautious observer, was the first to sound +the depths of heaven in order to determine the limits and form of the starry +stratum which we inhabit, and he, too, was the first who ventured to throw +the light of investigation upon the relations existing between the position +and distance of remote nebulae and our own portion of the sidereal universe. + William Herschel, as is well expressed in the elegant inscription on his +monument at Upton, broke through the inclosures of heaven ('caelorum +perrupit claustra'), and, like another Columbus, penetrated into an unknown +ocean, from which he beheld coasts and groups of islands, whose true +position it remains for future ages to determine. + +Considerations regarding the different intensity of light in stars, and +their relative number, that is to say, their numerical frequency on +telescopic fields of equal magnitude, have led to the assumption of unequal +distances and distribution in space in the strata which they compose. Such +assumptions, in as far as they may lead us to draw the limits of the +individual portions of the universe, can not offer the same degree of +mathematical certainty as that which may be attained in all that +p 88 +relates to our solar system, whether we consider the rotation of double +stars with unequal velocity round one common center of gravity, or the +apparent or true movements of all the heavenly bodies. If we take up the +physical description of the universe from the remotest nebulae, we may be +inclined to compare it with the mythical portions of history. The one +begins in the obscurity of antiquity, the other in that of inaccessible +space; and at the point where reality seems to flee before us, imagination +becomes doubly incited to draw from its own fullness, and give definite +outline and permanence to the changing forms of objects. + +If we compare the regions of the universe with one of the island-studded +seas of our own planet, we may imagine matter to be distributed in groups, +either as unresolvable nebulae of different ages, condensed around one or +more nuclei, or as already agglomerated into clusters of stars, or isolated +spheroidal bodies. The cluster of stars, to which our cosmical island +belongs, forms a lens-shaped, flattened stratum, detached on every side, +whose major axis is estimated at seven or eight hundred, and its minor one +at a hundred and fifty times the distance of Sirius. It would appear, on +the supposition that the parallax of Sirius is not greater than that +accurately determined for the brightest star in the Centaur (0".9128), that +light traverses one distance of Sirius in three years, while it also +follows, from Bessel's earlier excellent Memoir* on the parallax of the +remarkable star 61 Cygni (0".3483), (whose considerable motion might lead to +the inference of great proximity), that a period of nine years and a quarter +is required for the transmission of light from this star to our planet. + + +[footnote] *See Maclear's "Results from 1839 to 1840," in the 'Trans. of +the Astronomical Soc.', vol. xii., p. 370, on 'a' Centauri, the probable +mean error being 0".0649. For 61 Cygni, see Bessel, in Schumacher's +'Jahrbuch', 1839, s. 47, and Schumacher's 'Astron. Nachr.', bd. xviii., s. +401, 402, probable mean error, 0".0141. With reference to the relative +distances of stars of different magnitudes, how those of the third magnitude +may probably be three times more remote, and the manner in which we +represent to ourselves the material arrangement of the starry strata, I have +found the following remarkable passage in Kepler's 'Epitome Astronomiae +Copernicanae', 1618, t. i., lib. 1, p. 34-39: "Sol hic noster nil aliud est +quam una ex fixis, nobis major et clarior visa, quia propior quam fixa. +Pone terram stare ad latus, una semi-diametro via e lactea e, tunc ha ec via +lactea apparebit circulus parvus, vel ellipsis parva, tota declinans ad +latus alterum; eritque simul uno intuitu conspicua, quae nunc no potest nisi +dimidia conspici quovis momento. Itaque fix arum spha era non tantum orbe +stellarum, sed etiam circulo lactis versus not deorsum est terminata." + + +Our starry stratum is a disk of inconsiderable thickness, divided a +p 89 +third of its length into two branches; it is supposed that we are near this +division, and nearer to the region of Sirius than to the constellation +Aquila, almost in the middle of the stratum in the line of its thickness or +minor axis. + +This position of our solar system, and the form of the whole discoidal +stratum, have been inferred from sidereal scales, that is to say, from that +method of counting the stars to which I have already alluded, and which is +based upon the equidistant subdivision of the telescopic field of view. The +relative depth of the stratum in all directions is measured by the greater +or smaller number of stars appearing in each division. These divisions give +the length of the ray of vision in the same manner as we measure the depth +to which the plummet has been thrown, before it reaches the bottom, although +in the case of a starry stratum there can not, correctly speaking, be any +idea of depth, but merely of outer limits. In the direction of the longer +axis, where the stars lie behind one another, the more remote ones appear +closely crowded together, united, as it were, by a milky-white radiance or +luminous vapor, and are perspectively grouped, encircling as in a zone, the +visible vault of heaven. This narrow and branched girdle, studded with a +radiant light, and here and there interrupted by dark spots, deviates only +by a few degrees from forming a perfect large circle round the concave +sphere of heaven, owing to our being near the center of the large starry +cluster, and almost on the plane of the Milky Way. If our planetary system +were far 'outside' this cluster, the Milky Way would appear to telescopic +vision as a ring, and at a still greater distance as a resolvable discoidal +nebula. + +Among the many self-luminous moving suns, erroneously called 'fixed stars', +which constitute our cosmical island, our own sun is the only one known by +direct observation to be a 'central body' in its relations to spherical +agglomerations of matter directly depending upon and revolving round it, +either in the form of planets, comets, or aerolite asteroids. As far as we +have hitherto been able to investigate 'multiple' stars (double stars or +suns), these bodies are not subject, with respect to relative motion and +illumination, to the same planetary dependence that characterizes our own +solar system. Two or more self-luminous bodies, whose planets and moon, if +such exist, have hitherto escaped our telescopic powers of vision, certainly +revolve around one common center of gravity; but this is in a portion of +space which is probably occupied merely by unagglomerated matter or cosmical +vapor, while in our system +p 90 +the center of gravity is often comprised within the innermost limits of a +'visible' central body. If, therefore, we regard the Sun and the Earth, or +the Earth and the Moon, as double-stars, and the whole of our planetary +solar system as a multiple cluster of stars, the analogy thus suggested must +be limited to the universality of the laws of attraction in different +systems, being alike applicable to the independent processes of light and to +the method of illumination. + +For the generalization of cosmical views, corresponding with the plan we +have proposed to follow in giving a delineation of nature or of the +universe, the solar system to which the Earth belongs may be considered in a +two-fold relation: first, with respect to the different classes of +individually agglomerated matter, and the relative size, conformation, +density, and distance of the heavenly bodies of this system; and secondly, +with reference to other portions of our starry cluster, and of the changes +of position of its central body, the Sun. + +The solar system, that is to say, the variously-formed matter circling round +the Sun, consists, according to the present state of our knowledge of +'eleven primary planets',* eighteen satellites +p 91 +or secondary planets, and myriads of comets, three of which, known as the +"planetary comets," do not pass beyond the narrow limits of the orbits +described by the principal planets. + + +[footnote] * (Since the publication of Baron Humboldt's work in 1845, +several other planets have been discovered, making the number of those +belonging to our planetary system 'sixteen' instead of 'eleven'. Of these, +Astrea, Hebe, Flora, and Iris are members of the remarkable group of +asteroids between Mars and Jupiter. Astrea and Hebe were discovered by +Hencke at Driesen, the one in 1846 and the other in 1847; Flora and Iris +were both discovered in 1847 by Mr. Hind, at the South Villa Observatory, +Regent's Park. It would appear from the latest determinations of their +elements, that the small planets have the following order with respect to +mean distance from the Sun: Flora, Iris, Vesta, Hebe, Astrea, Juno, Ceres, +Pallas. Of these, Flora has the shortest period (about 3 1/4 years). The +planet Neptune, which, after having been predicted by several astronomers, +was actually observed on the 25th of September, 1846, is situated on the +confines of our planetary system beyond Uranus. The discovery of this +planet is not only highly interesting from the importance attached to it as +a question of science, but also from the evidence it affords of the care and +unremitting labor evinced by modern astronomers in the investigation and +comparison of the older calculations, and the ingenious application of the +results thus obtained to the observation of new facts. The merit of having +paved the way for the discovery of the planet Neptune is due to M. Bouvard, +who, in his persevering and assiduous efforts to deduce the entire orbit of +Uranus from observations made during the forty years that succeeded the +discovery of that planet in 1781, found the results yielded by theory to be +at variance with fact, in a degree that had no parallel in the history of +astronomy. This startling discrepancy, which seemed only to gain additional +weight from every attempt made by M. Bouvard to correct his calculations, +led Leverrier, after a careful modification of the tables of Bouvard, to +establish the proposition that there was "a formal incompatibility between +the observed motions of Uranus and the hypothesis that he was acted on +'only' by the Sun and known planets, according to the law of universal +gravitation." Pursuing this idea, Leverrier arrived at the conclusion that +the disturbing cause must be a 'planet', and finally, after an amount of +labor that seems perfectly overwhelming, he, on the 31st of August, 1846, +laid before the French Institute a paper, in which he indicated the exact +spot in the heavens where this new planetary body would be found, giving the +following data for its various elements: mean distance from the Sun, 36.154 +times that of the Earth; period of revolution, 217.387 years; mean long., +Jan. 1st, 1847, 318 degrees 47'; mass, 1/9300th; heliocentric long., Jan +1st1847, 326 degrees 32'. Essential difficulties still intervened, however, +and as the remoteness of the planet rendered it improbable that its disk +would be discernible by any telescopic instrument, no other means remained +for detecting the suspected body but its planetary motion, which could only +be ascertained by mapping, after every observation, the quarter of the +heavens scanned, and by a comparison of the various maps. Fortunately for +the verification of Leverrier's predictions, Dr. Bremiker had just completed +a map of the precise region in which it was expected the new planet would +apper, this being one of a series of maps made for the Academy of Berlin, of +the small stars along the entire zodiac. By means of this valuable +assistance, Dr. Galle, of the Berlin Observatory, was led, on the 25th of +September, 1846, by the discovery of a star of the eighth magnitude, not +recorded in Dr. Bremiker's map, to make the first observation of the planet +predicted by Leverrier. By a singular coincidence, Mr. Adams, of Cambridge, +had predicted the appearance of the planet simultaneously with M. Leverrier; +but by the concurrence of several circumstances much to be regretted, the +world at large were not made acquainted with Mr. Adams's valuable discovery +until subsequently to the period at which Leverrier published his +observations. As the data of Leverrier and Adams stand at present, there is +a discrepancy between the predicted and the true distance, and in some other +elements of the planet; it remains therefore, for these or future +astronomers to reconcile theory with fact, or perhaps, as in the case of +Uranus, to make the new planet the means of leading to yet greater +discoveries. It would appear from the most recent observations, that the +mass of Neptune, instead of being, as at first stated, 1/9300th, is only +about 1/23000th that of the Sun, while its periodic time is now given with a +greater probability at 166 years, and its mean distance from the Sun nearly +30. The planet appears to have a ring, but as yet no accurate observations +have been made regarding its system of satellites. See 'Trans. Astron. +Soc.', and 'The Planet Neptune', 1848, by J. P. Nicholl.) -- Tr. + + +We may, with no incondsiderable degree of probability, include within the +domain of our Sun, in the immediate sphere of its central force, a rotating +ring of vaporous matter, lying probably between the orbits of Venus and +Mars, but certainly beyond that of the Earth,* which appears to us in +p 92 +a pyramidal form, and is known as the 'Zodiacal Light'; and a host of very +small asteroids, whose orbits either intersect, or very nearly approach, +that of our earth, and which present us with the phenomena of aerolites and +falling or shooting stars. + + +[footnote] * "If there should be molecules in the zones diffused by the +atmosphere of the Sun of too volatile a nature either to combine with one +another or with the planets, we must suppose that they would, in circling +round that luminary, present all the appearances of zodiacal light, without +opposing any appreciable resistance to the different bodies composing the +planetary system, either owing to their extreme rarity, or to the similarity +existing between their motion and that of the planets with which they come +in contact." -- Laplace, 'Expos. du Syst. du Monde' (ed. 5), p. 415. + + +When we consider the complication of variously-formed bodies which revolve +round the Sun in orbits of such dissimilar eccentricity--although we may not +be disposed, with the immortal author of the 'Mecanique Celeste', to regard +the largr number of comets as nebulous stars, passing from one central +system to another,* we yet can not fail to acknowledge that the planetary +system, especially so called (that is, the group of heavenly bodies which, +together with their satellites, revolve with but slightly eccentric orbits +round the Sun), constitutes but a small portion of the whole system with +respect to individual numbers, if not to mass. + + +[footnote] *Laplace, 'Exp. du Syst. du Monde', p. 396, 414. + + +It has been proposed to consider the telescopic planets, Vesta, Juno, Ceres, +and Pallas, with their more closely intersecting, inclined, and eccentric +orbits, as a zone of separation, or as a middle group in space; and if this +view be adopted, we shall discover that the interior planetary group +(consisting of Mercury, Venus, the Earth, and Mars) presents several very +striking contrasts* when compared with the exterior group, comprising +Jupiter, Saturn, and Uranus. + + +[footnote] *Littrow, 'Astronomie', 1825, bd.xi., 107. Mädler, 'Astron.', +1841, § 212. Laplace, 'Exp. du Syst. du Monde', p. 210. + + +The planets nearest the Sun, and consequently included in the inner group, +are of more moderate size, denser, rotate more slowly and with nearly equal +velocity (their periods of revolution being almost all about 24 hours), are +less compressed at the poles, and with the exception of one, are without +satellites. The exterior planets, which are further removed from the Sun, +are very considerably larger, have a density five times less, more than +twice as great a velocity in the period of their rotation round their axes, +are more compressed at the poles, and if six satellites may be ascribed to +Uranus, have a quantitative preponderance in the number of their attendant +moons, which is as seventeen to one. + +p 93 +Such general considerations regarding certain characteristic properties +appertaining to whole groups, can not, however, be applied with equal +justice to the individual planets of every group, nor to the relations +between the distances of the revolving planets from the central body, and +their absolute size, density, period or rotation, eccentricity, and the +inclination of their orbits and the axes. We know as yet of no inherent +necessity, no mechanical natural law, similar to the one which teaches us +that the squares of the periodic times are proportional to the cubes of the +major axes, by which the above-named six elements of the planetary bodies +and the form of their orbit are made dependent either on one another, or on +their mean distance from the Sun. Mars is smaller than the Earth and Venus, +although further removed from the Sun than these last-named planets, +approaching most nearly in size to Mercury, the nearest planet to the Sun. +Saturn is smaller than Jupiter, and yet much larger than Uranus. The zone +of the telescopic planets, which have so inconsiderable a volume, +immediately procede Jupiter (the greatest in size of any of the planetary +bodies), if we consider them with regard to distance from the Sun; and yet +the disks of these small asteroids, which scarcely admit of measurement, +have an areal surface not much more than half that of France, Madagascar, or +Borneo. However striking may be the extremely small density of all the +colossal planets, which are furthest removed from the Sun, we are yet unable +in this respect to recognize any regular succession.* + + +[footnote] *See Kepler, on the increasing density and volume of the planets +in proportion with their increase of distance from the Sun, which is +described as the densest of all the heavenly bodies; in the 'Epitome Astran. +Copern. in' vii. 'libros digesta', 1618-1622, p. 420. Leibnitz also +inclined to the opinions of Kepler and Otto von Guericke, that the planets +increase in volume in proportion to their increase of distance from the Sun. + See his letter to the Magdeburg Burgomaster (Mayence, 1671), in Leibnitz, +'Deutschen Schriften, herausg. von Guhrauer', th. i., 264. + + +Uranus appears to be denser than Saturn, even if we adopt the smaller mass, +1/24605, assumed by Lamont; and, notwithstanding the inconsiderable +difference of density observed in the innermost planetary group,* we find +both Venus and Mars less dense than the Earth, which lies between them. + + +[footnote] *On the arrangement of masses, see Encke, in Schum., 'Astr. +Nachr', 1843 Nr. 488, 114. + + +The time of rotation certainly diminishes with increasing solar distance, +but yet it is greater in Mars than in the Earth, and in Saturn than in +Jupiter. The elliptic +p 94 +orbits of Juno, Pallas, and Mercury have the greatest degree of +eccentricity, and Mars and Venus, which immediately follow each other, have +the least. Mercury and Venus exhibit the same contrasts that may be +observed in the four smaller planets, or asteroids, whose paths are so +closely interwoven. + +The eccentriciities of Juno and Pallas are very nearly identical, and reach +three times as great as those of Ceres and Vesta. The same may be said of +the inclination of the orbits of the planets toward the plane of projection +of the ecliptic, or in the position of their axes of rotation with relation +to their orbits, a position on which the relations of climate, seasons of +the year, and length of the days depend more than on eccentricity. Those +planets that have the most elongated elliptic orbits, as Juno, Pallas, and +Mercury, have also, although not to the same degree their orbits most +strongly inclined toward the ecliptic. Pallas has a comet-like inclination +nearly twenty-six times greater than that of Jupiter, while in the little +planet Vesta, which is so near Pallas, the angle of inclination scarcely by +six times exceeds that of Jupiter. An equally irregular succession is +observed in the position of the axes of the few planets (four or five) whose +planes of rotation we know with any degree of certainty. It would appear +from the position of the satellites of Uranus, two of which, the second and +fourth, have been recently observed with certainty, that the axis of this, +the outermost of all the planets is scarcely inclined as much as 11 degrees +toward the plane of its orbit, while Saturn is placed between this planet, +whose axis almost coincides with the plane of its orbit, and Jupiter, whose +axis of rotation is nearly perpendicular to it. + +In this enumeration of the forms which compose the world in space, we have +delineated them as possessing an actual existence, and not as objects of +intellectual contemplation, or as mere links of a mental and causal chain of +connection. The planetary system, in its relations of absolute size and +relative position of the axes, density, time of rotation, and different +degrees of eccentricity of the orbits, does not appear to offer to our +apprehension any stronger evidence of a natural necessity than the +proportion observed in the distribution of land and water on the Earth, the +configuration of continents, or the height of mountain chains. In these +respects we can discover no common law in the regions of space or in the +inequalities of the earth's crust. They are 'facts' in nature that have +arisen from the conflict of manifold forces acting under unknown +p 95 +conditions, although man considers as 'accidental' whatever he is unable to +explain in the planetary formation on purely genetic principles. If the +planets have been formed out of separate rings of vaporous matter revolving +round the Sun, we may conjecture that the different thickness, unequal +density, temperature, and electro-magnetic tension of these rings may have +given occasion to the most various agglomerations of matter, in the same +manner as the amount of tangential velocity and small variations in its +direction have produced so great a differencein the forms and inclinations +of the elliptic orbits. Attractions of mass and laws of gravitation have no +doubt exercised an influence here, no less than in the geognostic relations +of the elevations of continents; but we are unable from the present forms to +draw any conclusions regarding the series of conditions through which they +have passed. Even the so-called law of the distances of the planets from +the Sun, the law of progression (which led Kepler to conjecture the +existence of a planet supplying the link that was wanting in the chain of +connection between Mars and Jupiter), has been found numerically inexact for +the distances between Mercury, Venus, and the Earth, and a variance with the +conception of a series, owing to the necessity for a supposition in the case +of the first member. + +The hitherto disscovered principal planets that revolve round our Sun are +attended certainly by fourteen, and probably by eighteen secondary planets +(moons or satellites). The principal planets are, therefore, themselves the +central bodies of subordinate systems. We seem to recognize in the fabric +of the universe the same process of arrangement so frequently exhibited in +the development of organic life, where we find in the manifold combinations +of groups of plants or animals the same typical form repeated in the +'subordinate classes'. The secondary planets or satellites are more +frequent in the external region of the planetary system, lying beyond the +intersecting orbits of the smaller planets or asteroids; in the inner region +none of the planets are attended by satellites, with the exception of the +Earth, whose moon is relatively of great magnitude, since its diameter is +equal to a fourth of that of the Earth, while the diameter of the largest of +all known secondary planets -- the sixth satellite of Saturn -- is probably +about one seventeenth, and the largest of Jupiter's moons, the third, only +about one twenty-sixth part that of the primary planet or central body. The +planets which are attended by the largest number of satellites are most +remote from the Sun, +p 96 +and are at the same time the largest, most compressed at the poles, and the +least dense. According to the most recent measurements of Mädler, Uranus +has a greater planetary compression than any other of the planets, viz., +1/9.92d. In our Earth and her moon, whose mean distance from one another +amounts to 207,200 miles, we find that the differences of mass* and diameter +between the two are much less considerable than are usually observed to +exist between the principal planets and their attendant satellites, or +between bodies of different orders in the solar system. + + +[footnote] *If, according to Burckhardt's determination, the Moon's radius +be 0.2725 and its volume 1/49.00th, its density will be 0.5596, or nearly +five ninths. Compare, also, Wilh. Beer and H. Madler, 'der Mond', 2, 10, +and Madler, 'Ast.', 157. The material contents of the Moon are, according +to Hansen, nearly 1/34th (and ädler 1/40.6th) that of the Earth, and its +mass equal to 1/87.73d that of the Earth. In the largest of Jupiter's +moons, the third, the relations of volume to the central body are 1/15370th, +and of mass 1/11300th. On the polar flattening of Uranus, see Schum, +'Astron. Nachr.', 1844, No. 493. + + +While the density of the Moon is five ninths less than that of the Earth, it +would appear, if we may sufficiently depend upon the determinations of their +magnitudes and masses, that the second of Jupiter's moons is actually denser +than that great planet itself. Among the fourteen satellites that have been +investigated with any degree of certainty, the system of the seven +satellites of Saturn presents an instance of the greatest possible contrast, +both in absolute magnitude and in distance from the central body. The sixth +of these satellites is probably not much smaller than Mars, while our moon +has a diameter which does not amount to more than half that of the latter +planet. With respect to volume, the two outer, the sixth and seventh of +Saturn's satellites, approach the nearest to the third and brightest of +Jupiter's moons. The two innermost of these satellites belong perhaps, +together with the remote moons of Uranus to the smallest cosmical bodies of +our solar system, being only made visible under favorable circumstances by +the most powerful instruments. They were first discovered by the forty-foot +telescope of William Herschel in 1789, and were seen again by John Herschel +at the Cape of Good Hope, by Vico at Rome, and by Lamont at Munich. +Determinations of the 'true' diameter of satellites, made by the measurement +of the apparent size of their small disks, are subjected to many optical +difficulties; but numerical astronomy, whose task it is to predetermine by +calculation the motions of the heavenly bodies as they will appear when +viewed from the Earth, is directed almost +p 97 +exclusively to motion and mass, and but little to volume. The absolute +distance of a satellite from its central body is greatest in the case of the +outermost or seventh satellite of Saturn, its distance from the body round +which it revolves amounting to more than two millions of miles, or ten times +as great a distance as that of our moon from the Earth. In the case of +Jupiter we find that the outermost or fourth attendant moon is only +1,040,000 miles from that planet, while the distance between Uranus and its +sixth satellite (if the latter really exist) amounts to as much as 1,360,000 +miles. If we compare, in each of these subordinate systems, the volume of +the satellite, we discover the existence of entirely new numerical +relations. The distances of the outermost satellites of Uranus, Saturn, and +Jupiter are when expressed in semi-diameters of the main planets, as 91, 64, +and 27. The outermost satellite of Saturn appears, therefore, to be removed +only about one fifteenth further from the center of that planet than our +moon is from the Earth. The first or innermost of Saturn's satellites is +nearer to its central body than any other of the secondary planets, and +presents, moreover, the only instance of a period of revolution of less than +twenty-four hours. Its distance from the center of Saturn may, according to +Mädler and Wilhelm Beer, be expressed as 2.47 semi-diameters of that +planet, or as 80,088 miles. Its distance from the surface of the main +planet is therefore 47,480 miles, and from the outer-most edge of the ring +only 4916 miles. The traveler may form to himself an estimate of the +smallness of this amount by remembering the statement of an enterprising +navigator, Captain Beechey, that he had in three years passed over 72,800 +miles. If, instead of absolute distances, we take the semi-diameters of the +principal planets, we shall find that even the first or nearest of the moons +of Jupiter (which is 26,000 miles further removed from the center of that +planet than our moon is from that of the Earth) is only six semi-diameters +of Jupiter from its center, while our moon is removed from us fully 60 1/3d +semi-diameters of the Earth. + +In the subordinate systems of satellites, we find that the same laws of +gravitation which regulate the revolutions of the principal planets round +the Sun likewise govern the mutual relations existing between these planets +among one another and with reference to their attendant satellites. The +twelve moons of Saturn, Jupiter, and the Earth all most like the primary +planets from west to east, and in elliptic orbits, deviating +p 98 +but little from circles. It is only in the case of one moon, and perhaps in +that of the first and innermost of the satellites of Saturn (0.068), that we +discover an eccentricity greater than that of Jupiter; according to the very +exact observations of Bessel, the eccentricity of the sixth of Saturn's +satellites (0.029) exceeds that of the Earth. On the extremest limits of +the planetary system, where, at a distance nineteen times greater than that +of our Earth, the centripetal force of the Sun is greatly diminished, the +satellites of Uranus (which most striking contrasts from the facts observed +with regard to other secondary planets. Instead, as in all other +satellites, of having their orbits but slightly inclined toward the ecliptic +and (not excepting even Saturn's ring, which may be regarded as a fusion of +agglomerated satellites) moving from west to east, the satellites of Uranus +are almost perpendicular to the ecliptic, and move retrogressively from east +to west, as Sir John Herschel has proved by observations continued during +many years. If the primary and secondary planets have been formed by the +condensation of rotating rings of solar and planetary atmospheric vapor, +there must have existed singular causes of retardation or impediment in the +vaporous rings revolving round Uranus, by which, under the relations with +which we are unacquainted, the revolution of the second and fourth of its +satellites was made to assume a direction opposite to that of the rotation +of the central planet. + +It seems highly probable that the period of rotation of 'all' secondary +planets is equal to that of their revolution round the main planet, and +therefore that they always present to the latter the same side. +Inequalities, occasioned by sight variations in the revolution, give rise to +fluctuations of from 6 degrees to 8 degrees, or to an apparent libration in +longitude as well as in latitude. Thus, in the case of our moon, we +sometimes observe more than the half of its surface, the eastern and +northern edges being more visible at one time, and the western or southern +at another. By means of this libration* we are enabled to see the annular +mountain Malapert (which occasionally conceals the Moon's south pole), the +arctic landscape round the crater of Gioja, and the large gray plane near +Endymion which exceeds in superficial extent the 'Mare Vaporum'. + + +[footnote] *Beer and Madler, op. cit., 185, s.208, and § 347, s. 332; and +ix their 'Phys. Kenntniss der himml. Korper', s. 4 und 69, Tab. 1 (Physical +History of the Heavenly Bodies). + + +Three sevenths of the Moon's surface are entirely +p 99 +concealed from our observation, and must always remain so, unless new and +unexpected disturbing causes come into play. These cosmical relations +involuntarily remind us of nearly similar conditions in the intellectual +world, where, in the domain of deep research into the mysteries and the +primeval creative forces of nature, there are regions similarly turned away +from us, and apparently unattainable, of which only a narrow margin has +revealed itself, for thousands of years, to the human mind, appearing, from +time to time, either glimmering in true or delusive light. We have hitherto +considered the primary planets, their satellites, and the concentric rings +which belong to one, at least, of the outermost planets, as products of +tangential force, and as closely connected together by mutual attraction; it +therefore now only remains for us to speak of the unnumbered host of +'comets' which constitute a portion of the cosmical bodies revolving in +independent orbits round the Sun. If we assume an equable distribution of +their orbits, and the limits of their perihelia, or greatest proximities to +the Sun, and the possibility of their remaining invisible to the inhabitants +of the Earth, and base our estimates on the rules of the calculus of +probabilities, we shall obtain as the result an amount of myriads perfectly +astonishing. Kepler, with his usual animation of expression, said that +there were more comets in the regions of space than fishes in the depths of +the ocean. As yet, however, there are scarcely one hundred and fifty whose +paths have been calculated, if we may assume at six or seven hundred the +number of comets whose appearance and passage through known constellations +have been ascertained by more or less precise observations. While the +so-called classical nations of the West, the Greeks and Romans, although +they may occasionally have indicated the position in which a comet first +appeared, never afford any information regarding its apparent path, the +copious literature of the Chinese (who observed nature carefully, and +recorded with accuracy what they saw) contains circumstantial notices of the +constellations through which each comet was observed to pass. These notices +go back to more than five hundred years before the Christian era, and many +of them are still found to be of value in astronomical observations.* + + +[footnote] *The first comets of whose orbits we have any knowledge, and +which were calculated from Chinese observations, are those of 240 (under +Gordian II.), 539 (under Justinian), 565, 568, 574, 837, 1337, and 1385. +See John Russell Hind, in Schum., 'Astron. Nachr.', 1843, No. 498. While +the comet of 837 (which, according to Du Sejour, continued during +twenty-four hours within a distance of 2,000,000 miles from the Earth) +terrified Louis I. of France to that degree that he busied himself in +building churches and founding monastic establishments, in the hope of +appeasing the evils threatened by its appearance, the Chinese astronomers +made observations on the path of this cosmical body, whose tail extended +over a space of 60 degrees, appearing sometimes single and sometimes +multiple. The first comet that has been calculated solely from European +observations was that of 1456, known as Halley's comet, from the belief +long, but erroneously, entertained that the period when it was first +observed by that astronomer was its first and only well-attested appearance. + See Arago, in the 'Annuaire', 1836, p. 204, and Langier, 'Comptes Rendus +des Seances de l'Acad.', 1843, t. xvi., 1006. + + +p 100 +Although comets have a smaller mass than any other cosmical bodies -- being, +according to our present knowledge, probably not equal to 1/5000th part of +the Earth's mass -- yet they occupy the largest space, as their tails in +several instances extend over many millions of miles. The cone of luminous +vapor which radiates from them has been found, in some cases (as in 1680 and +1811), to equal the length of the Earth's distance from the Sun, forming a +line that intersects both the orbits of Venus and Mercury. It is even +probable that the vapor of the tails of comets mingled with our atmosphere +in the years 1819 and 1823. + +Comets exhibit such diversities of form, which appear rather to appertain to +the individual than the class, that a description of one of these "wandering +light-clouds," as they were already called by Xenophanes and Theon of +Alexandria, contemporaries of Pappus, can only be applied with caution to +another. The faintest telescopic comets are generally devoid of visible +tails, and resemble Herschel's nebulous stars. They appear like circular +nebulae of faintly-glimmering vapor, with the light concentrted toward the +middle. This is the most simple type; but it can not, however, be regarded +as rudimentary, since it might equally be the type of an older cosmical +body, exhausted by exhalation. In the larger comets we may distinguish both +the so-called "head" or "nucleus," and the single or multiple tail, which is +characteristically denominated by the Chinese astronomers "the brush" +('sui'). The nucleus generally presents no definite outline, although, in a +few rare cases, it appears like a star of the first or second magnitude, and +has even been seen in bright sunshine;* as, +p 101 +for instance, in the large comets of 1402, 1532, 1577, 1744, and 1843. + + +[footnote] *Arago, 'Annuaire', 1832, p. 209, 211. The phenomenon of the +tail of a comet being visible in bright sunshine, which is recorded of the +comet of 1402, occurred again in the case of the large comet of 1843, whose +nucleus and tail were seen in North America on the 28th of February +(according to the testimony of J. G. Clarke, of Portland, state of Maine), +between 1 and 3 o'clock in the afternoon.(a) The distance of the very dense +nucleus from the sun's light admitted of being measured with much exactness. + The nucleus and tail appeared like a very pure white cloud, a darker space +intervening between the tail and the nucleus. ('Amer. Journ. of Science', +vol. xiv., No. 1, p. 229.) + + +[footnote] (a) [The translator was at New Bedford, Massachusetts, U.S., on +the 28th February, 1843, and distinctly saw the comet, between 1 and 2 in +the afternoon. The sky at the time was intensely blue, and the sun shining +with a dazzling brightness unknown in European climates.] -- Tr + + +This latter circumstance indicates, in particular individuals, a denser +mass, capable of reflecting light with greater intensity. Even in +Herschel's large telescope, only two comets, that discovered in Sicily in +1807, and the splendid one of 1811, exhibited well-defined disks;* the one +at an angle of 1 second, and the other at 0.77 seconds, whence the true +diameters are assumed to be 536 and 428 miles. + + +[footnote] *'Phil. Trans.' for 1808, Part ii., p. 155, and for 1812, Part +i., p. 118. The diameters found by Herschel for the nuclei were 538 and 428 +English miles. For the magnitudes of the comets of 1798 and 1805, see +Arago, 'Annuaire', 1832, p. 203. + + +The diameters of the less well-defined nuclei of the comets of 1798 and 1805 +did not appear to exceed 24 or 28 miles. + +In several comets that have been investigated with great care, especially in +the above-named one of 1811, which continued visible for so long a period, +the nucleus and its nebulous envelope were entirely separated from the tail +by a darker space. The intensity of light in the nucleus of comets does not +augment toward the center in any uniform degree, brightly shining zones +being in many cases separated by concentric nebulous envelopes. The tails +sometimes appear single, sometimes, although more rarely, double; and in the +comets of 1807 and 1843 the branches were of different lengths; in one +instance (1744) the tail had six branches, the whole forming an angle of 60 +degrees. The tails have been sometimes straight, sometimes curved, either +toward both sides, or toward the side appearing to us as the exterior (as in +1811), or convex toward the direction in which the comet is moving (as in +that of 1618); and sometimes the tail has even appeared like a flame in +motion. The tails are always turned away from the sun, so that their line +of prolongation passes through its center; a fact which, according to Edward +Biot, was noticed by the Chinese astronomers as early as 837, but was first +generally made known in Europe by Fracastoro and Peter Apian in the +sixteenth century. These emanations may be regarded as conoidal envelopes +of greater of less thickness, +p 102 +and, considered in this manner, they furnish a simple explanation of many of +the remarkable optical phenomena already spoken of. + +Comets are not only characteristically different in form, some being +entirely without a visible tail, while others have a tail of immense length +(as in the instance of the comet of 1618, whose tail measured 104 degrees), +but we also see the same comets undergoing successive and rapidly-changing +processes of configuration. These variations of form have been most +accurately and admirably described in the comet of 1744, by Hensius, at St. +Petersburg, and in Halley's comet, on its last reappearance in 1835, by +Bessel, at Konigsberg. A more or less well-defined tuft of rays emanated +from that part of the nucleus which was turned toward the Sun; and the rays +being bent backward, formed a part of the tail. The nucleus of Halley's +comet; with its emanations, presented the appearance of a burning rocket, +the end of which was turned sideways by the force of the wind. The rays +issuing from the head were seen by Arago and myself, at the Observatory at +Paris, to assume very different forms on successive nights.* + + +[footnote] *Arago, 'Des Changements physiques de la Comete de Halley du +15-23 Oct., 1835. 'Annuaire', 1836, p. 218, 221. The ordinary direction of +the emanations was noticed even in Nero's time. "Comae radios solis +effugiunt." -- Seneca, 'Nat. Quaest.', vii., 20. + + +The great Konigsberg astronomer concluded from many measurements, and from +theoretical considerations, "that the cone of light issuing from the comet +deviated considerably both to the right and the left of the true direction +of the Sun, but that it always returned to that direction, and passed over +to the opposite side, so that both the cone of light and the body of the +comet from whence it emanated experienced a rotatory, or, rather, a +vibratory motion in the plane of the orbit." He finds that "the attractive +force exercised by the Sun on heavy bodies is inadequate to explain such +vibrations, and is of opinion that they indicate a polar force, which turns +one semi-diameter of the comet toward the Sun, and strives to turn the +opposite side away from that luminary. The magnetic polarity possessed by +the Earth may present some analogy to this, and, should the Sun have an +opposite polarity, an influence might be manifested, resulting in the +precession of the equinoxes." This is not the place to enter more fully +upon the grounds on which explanations of this subject have been based; but +observations so remarkable,* and views of so exalted +p 103 +a character, regarding the most wonderful class of the cosmical bodies +belonging to our solar system, ought not to be entirely passed over in this +sketch of a general picture of nature. + + +[footnote] *Bessel, in Schumacher, 'Astr. Nachr.', 1836, No. 300-302, s. +188, 192, 197, 200, 202, und 230. Also in Schumacher, 'Jahrb.', 1837, s. +149, 168. William Herschel, in his observations on the beautiful comet of +1811, believed that he had discovered evidences of the rotation of the +nucleus and tail ('Phil. Trans.' for 1812, Part i., p. 140). Dunlop, at +Paramatta thought the same with reference to the third comet of 1825. + + +Although, as a rule, the tails of comets increase in magnitude and +brilliancy in the vicinity of the sun, and are directed away from that +central body, yet the comet of 1823 offered the remarkable example of two +tails, one of which was turned toward the sun, and the other away from it, +forming with each other an angle of 160 degrees. Modifications of polarity +and the unequal manner of its distribution, and of the direction in which it +is conducted, may in this rare instance have occasioned a double, unchecked, +continuous emanation of nebulous matter.* + + +[footnote] *Bessel, in 'Astr. Nachr.', 1836, No. 302, s. 231. Schum, +'Jahrb.', 1837 s. 175. See, also Lehmann, 'Ueber Cometenschweife' (On the +Tails of Comets), in Bode, 'Astron. Jahrb. fur' 1826, s. 168. + + +Aristotle, in his 'Natural Philosophy', makes these emanations the means of +bringing the phenomena of comets into a singular connection with the +existence of the Milky Way. According to his views, the innumerable +quantity of stars which compose this starry zone give out a self-luminous, +incandescent matter. The nebulous belt which separates the different +portions of the vault of heaven was therefore regarded by the Stagirite as a +large comet, the substance of which was incessantly being renewed.* + + +[footnote] *Aristot., 'Meteor.', i., 8, 11-14, und 19-21 (ed. Ideler, t. +i., p. 32-34). Biese, 'Phil. des Aristoteles', bd. ii., s. 86. Since +Aristotle exercised so great an influence throughout the whole of the Middle +Ages, it is very much to be regretted that he was so averse to those grander +views of the elder Pythagoreans, which inculcated ideas so nearly +approximating to truth respecting the structure of the universe. He asserts +that comets are transitory meteors belonging to our atmosphere in the very +book in which he cites the opinion of the Pythagorean school, according to +which these cosmical bodies are supposed to be planets having long periods +of revolution. (Aristot., i., 6, 2.) This Pythagorean doctrine, which, +according to the testimony of Apollonius Myndius, was still more ancient, +having originated with the Chaldeans, passed over to the Romans, who in this +instance, as was their usual practice, were merely the copiers of others. +The Myndian philosopher describes the path of comets as directed toward the +upper and remote regions of heaven. Hence Seneca says, in his 'Nat. +Quaest.', vii., 17: "Cometes non est species falsa, sed proprium sidus +sicut solis et lunae: altiora mundi secat et tunc demum apparet quum in +imum cursum sui venit;" and again (at vii., 27), "Cometes aternos esse et +sortis ejusdem, cujus caetera (sidera), etiamsi faciem illis non habent +similem." Pliny (ii., 25) also refers to Apollonius Myndius, when he says, +"Sunt qui et haec sidera perpetua esse credant suoque ambitu ire, sed non +nisi relicta a sole cerni." + + +p 104 +The occulation of the fixed stars by the nucleus of a comet, or by its +innermost vaporous envelopes, might throw some light on the physical +character of these wonderful bodies; but we are unfortunately deficient in +observations by which we may be assured* that the occulation was perfectly +central; for, as it has already been observed, the parts of the envelope +contiguous to the nucleus are alternately composed of layers of dense or +very attenuated vapor. + + +[footnote] *Olbers, in 'Astr. Nachr.', 1828, s. 157, 184. Arago, 'De la +Constitution physique des Cometes; Annuaire de' 1832, p. 203, 208. The +ancients were struck by the phenomenon that it was possible to see through +comets as through a flame. The earliest evidence to be met with of stars +having been seen through comets is that of Democritus (Aristot., 'Meteor.', +i., 6, 11), and the statement leads Aristotle to make the not unimportant +remark, that he himself had observed the occulation of one of the stars of +Gemini by Jupiter. Seneca only speaks decidedly of the transparence of the +tail of comets. "We may see," says he, "stars through a comet as through a +cloud ('Nat. Quaest.', vii., 18); but we can ony see through the rays of the +tail, and not through the body of the comet itself: 'non in ea parte qua +sidus ipsum est spissi et solidi ignis, sed qua rarus splendor occurrit et +in crines dispergitur. Per intervalla ignium, non er ipsos, vides" (vii., +26). The last remark is unnecessary, since, as Galileo observed in the +'Saggiatore (Lettera a Monsignor Cesarini', 1619), we can certainly see +through a flame when it is not of too great a thickness'. + + +On the other hand the carefully conducted measurements of Bessel prove, +beyond all doubt, that on the 29th of September, 1835, the light of a star +of the tenth magnitude, which was then at a distance of 7".78 from the +central point of the head of Halley's comet, passed through very dense +nebulous matter, without experiencing any deflection during its passage.* + + +[footnote] *Bessel, in the 'Astron. Nachr.', 1836, No. 301, s. 204, 206. +Struve, in 'Recueil des Mem. de l'Acad. de St. Peterab.', 1836, p. 140, 143, +and 'Astr. Nachr.', 1836, No. 303, s. 238, writes as follows: "At Dorpat +the star was in conjunction only 2".2 from the brightest point of the comet. + The star remained continually visible, and its light was not perceptibly +diminished, while the nucleus of the comet seemed to be almost extinguished +before the radiance of the small star of the ninth or tenth magnitude." + + +If such an absence of refracting power must be ascribed to the nucleus of a +comet, we can scarcely regard the matter composing comets as a gaseous +fluid. The question here arises whether this absence of refracting power +may not be owing to the extreme tenuity of the fluid; or does the comet +consist of separated particles, constituting a cosmical stratum of clouds, +which, like the clouds of our atmosphere, that exercise no influence on the +p 105 +zenith distance of the stars, does not affect the ray of light passing +through it? In the passage of a comet over a star, a more or less +considerable diminution of light has often been observed; but this has been +justly ascribed to the brightness of the ground from which the star seems to +stand forth during the passage of the comet. + +The most important and decisive observations that we possess on the nature +and the light of comets are due to Arago's polarization experiments. His +polariscope instructs us regarding the physical constitution of the Sun and +comets, indicating whether a ray that reaches us from a distance of many +millions of miles transmits light directly or by reflection; and if the +former, whther the source of light is a solid, a liquid, or a gaseous body. +His apparatus was used at the Paris Observatory in examining the light of +Capella and that of the great comet of 1819. The latter showed polarized, +and therefore reflected light, while the fixed star, as was to be expected, +appeared to be a self-luminous sun.* + + +[footnote] *On the 3d of July, 1819, Arago made the first attempt to +analyze the light of comets by polarization, on the evening of the sudden +appearance of the great comet. I was present at the Paris Observatory, and +was fully convinced, as were also Matthieu and the late Bouvard of the +dissimilarity in the intensity of the light seen in the polariscope, when +the instrument received cometary light. When it received light from +Capella, which was near the comet, and at an equal altitude, the images were +of equal intensity. On the reappearance of Halley's comet in 1835, the +instrument was altered so as to give, according to Arago's chromatic +polarization, two images of complementary colors (green and red). ('Annales +de Chimie', t. xiii., p. 108; 'Annuaire', 1832, p. 216.) "We must conclude +from these observations," says Arago, "that the cometary light was not +entirely composed of rays having the properties of direct light, there being +light which was reflected specularly or polarized, that is, coming from the +sun. It can not be stated with absolute certainty that comets shine only +with borrowed light, for bodies, in becoming self-luminous, do not, on that +account, lose the power of reflecting foreign light." + + +The existance of polarized cometary light announced itself not only by the +inequality of the images, but was proved with greater certainty on the +reappearance of Halley's comet, in the year 1835, by the more striking +contrast of the complementary colors, deduced from the laws of chromatic +polarization discovered by Arago in 1811. These beautiful experiments still +leave it undecided whether, in addition to this reflected solar light, +comets may not have light of their own. Even in the case of the planets, +as, for instance, in Venus, an evolution of independent light seems very +probable. + +The variable intensity of light in comets can not always be +p 106 +explained by the position of their orbits and their distance from the Sun. +It would seem to indicate, in some individuals, the existence of an inherent +process of condensation, and an increased or diminished capacity of +reflecting borrowed light. In the comet of 1618, and in that which has a +period of three years, it was observed first by Hevelius that the nucleus of +the comet diminished at its perihelion and enlarged at its aphelion, a fact +which, after remaining long unheeded, was again noticed by the talented +astronomer Valz at Nismes. The regularity of the change of volume, +according to the different degrees of distance from the Sun, appears very +striking. The physical explanation of the phenomenon can not, however, be +sought in the condensed layers of cosmical vapor occurring in the vicinity +of the Sun, since it is difficult to imagine the nebulous envelope of the +nucleus of the comet to be vesicular and impervious to the other.* + + +[footnote] *Arago, in the 'Annuaire', 1832, p. 217-220. Sir John Herschel, +'Astron.', 488. + + +The dissimilar eccentricity of the orbits of comets has, in recent times +(1819), in the most brilliant manner enriched our knowledge of the solar +system. Encke has discovered the existence of a comet of so short a period +of revolution that it remains entirely within the limits of our planetary +system, attaining its aphelion between the orbits of the smaller planets and +that of Jupiter. Its eccentricity must be assumed at 0.845, that of Juno +(which has the greatest eccentricity of any of the planets) being 0.255. +Encke's comet has several times, although with difficulty, been observed by +the naked eye, as in Europe in 1819, and according to Rumker, in New Holland +in 1822. Its period of revolution is about 3 1/3d years; but, from a +careful comparison of the epochs of its return to its perihelion, the +remarkable fact has been discovered that these periods have diminished in +the most regular manner between the years 1786 and 1838, the diminution +amounting, in the course of 52 years, to about 1 3/10th days. The attempt +to bring into unison the results of observation and calculation in the +investigation of all the planetary disturbances, with the view of explaining +this phenomenon, has led to the adoption of the very probable hypothesis +that there exists dispersed in space a vaporous substance capable of acting +as a resisting medium. This matter diminished the tangential force, and +with it the major axis of the comet's orbit. The value of the constant of +the resistance appears to be somewhat different before and after the +perihelion; and this may, perhaps, be ascribed +p 107 +to the altered form of the small nebulous star in the vicinity of the Sun, +and to the action of the unequal density of the strata of cosmical ether.* + + +[footnote] *Encke, in the 'Astronomiche Nachrichten', 1843, No. 489, s. +130-132. + + +These facts, and the investigations to which they have led, belong to the +most interesting results of modern astronomy. Encke's comet has been the +means of leading astronomers to a more exact investigation of Jupiter's mass +(a most important point with reference to the calculation of perturbations); +and, more recently, the course of this comet has obtained for us the first +determination, although only an approximative one, of a smaller mass for +Mercury. + +The discovery of Encke's comet, which had a period of only 3 1/3d years, was +speedily followed, in 1826, by that of another, Biela's comet, whose period +of revolution is 6 3/4th years, and which is likewise planetary, having its +aphelion beyond the orbit of Jupiter, but within that of Saturn. It has a +fainter light than Encke's comet, and, like the latter, its motion is +direct, while Halley's comet moves in a course opposite to that pursued by +the planets. Biela's comet presents the first certain example of the orbit +of a comet intersecting that of the Earth. This position, with reference to +our planet, may therefore be productive of danger, if we can associate an +idea of danger with so extraordinary a natural phenomenon, whose history +presents no parallel, and the results of which we are consequently unable +correctly to estimate. Small masses endowed with enormous velocity may +certainly exercise a considerable power; but Laplace has shown that the mass +of the comet of 1770 is probably not equal to 1/5000th that of the Earth, or +about 1/2000th that of the Moon.* + + +[footnote] *Laplace, 'Expos. du Syst. du Monde', p. 216, 237. + + +We must not confound the passage of Biela's comet through the Earth's orbit +with its proximity to, or collision with our globe. When this passage took +place, on the 29th of October, 1832, it required a full month before the +Earth would reach the point of intersection of the two orbits. These two +comets of short periods of revolution also intersect each other, and it has +been justly observed,* that amid the many perturbations experienced by such +small bodies from the largr planets, there is a 'possibility' -- supposing a +meeting of these comets to occur in October -- that the inhabitants of the +Earth may witness the extraordinary spectacle of an encounter between two +cosmical bodies, and possibly of their reciprocal penetration and +amalgamation, or of their destruction by means of exhausting emanations. + + +[footnote] *Littrow, 'Beschreibende Astron.', 1835, s. 274. On the inner +comet recently discovered by M. Faye, at the Observatory of Paris, and whose +eccentricity is 0.551, its distance at its perihelion 1.690, and its +distance at its aphelion 5.832, see Schumacher, 'Astron. Nachr.', 1844, No. +495. Regarding the supposed identity of the comet of 1766 with the third +comet of 1819, see 'Astr. Nachr.', 1833, No. 239; and on the identity of the +comet of 1743 and the fourth comet of 1819, see No. 237 or the last +mentioned work. + + +Events of this nature, resulting either from deflection occasioned by +disturbing masses or primevally intersecting orbits, must have been of +frequent occurrence in the course of millions of years in the immeasurable +regions of ethereal space; but they must be regarded as isolated +occurrences, exercising no more general or alternative effects on cosmical +relations than the breaking forth or extinction of a volcano within the +limited sphere of our Earth. + +A third interior comet, having likewise a short period of revolution was +discovered by Faye on the 22d of November, 1843, at the Observatory at +Paris. Its elliptic path, which approaches much more nearly to a circle +than that of any other known comet, is included within the orbits of Mars +and Saturn. This comet, therefore, which, according to Goldschmidt, passes +beyond the orbit of Jupiter, is one of the few whose perihelia are beyond +Mars. Its period of revolution is 7 29/100 years, and it is not improbable +that the form of its present orbit may be owing to its great approximation +to Jupiter at the close of the year 1839. + +If we consider the comets in their inclosed elliptic orbits as members of +our solar system, and with respect to the length of their major axes, the +amount of their eccentricity, and their periods of revolution, we shall +probably find that the three planetary comets of Encke, Biela, and Faye are +most nearly approached in these respects, first, by the comet discovered in +1766 by Messier, and which is regarded by Clausen as identical with the +third comet of 1819; and next, by the fourth comet of the last-mentioned +year, discovered by Blaupain, but considered by Clausen as identical with +that of the year 1743, and whose orbit appears, like that of Lexell's comet, +to have suffered great variations from the proximity and attraction of +Jupiter. The two last-named comets would likewise seem to have a period of +revolution not exceeding five or six years, and their aphelia are in the +vicinity of Jupiter's orbit. Among the comets that have a period of +revolution of from seventy to +p 109 +seventy-six years, the first in point of importance with respect to +theoretical and physical astronomy is Halley's comet, whose last appearance, +in 1835, was much less brilliant than was to be expected from preceding +ones; next we would notice Olbers's comet, discovered on the 6th of March, +1815; and, lastly, the comet discovered by Pons in the year 1812, and whose +elliptic orbit has been determined by Encke. The two latter comets were +invisible to the naked eye. We now know with certainty of nine returns of +Halley's large comet, it having recently been proved by Laugier's +calculations*, that in the Chinese table of comets, first made known to us +by Edward Biot, the comet of 1378 is identical with Halley's; its periods of +revolution have varied in the interval between 1378 and 1835 from 74.91 to +77.58 years, the mean being 76.1. + + +[footnote] *Laugier, in the 'Comptes Rendus des Seances de l'Academie', +1843, t. xvi., p. 1006. + + +A host of other comets may be contrasted with the cosmical bodies of which +we have spoken, requiring several thousand years to perform their orbits, +which it is difficult to determine with any degree of certainty. The +beautiful comet of 1811 requires, according to Argelander, a period of 3065 +years for its revolution, and the colossal one of 1680 as much as 8800 +years, according to Encke's calculation. These bodies respectively recede, +therefore, 21 and 44 times further than Uranus from the Sun, that is to say, +33,600 and 70,400 millions of miles. At this enormous distance the +attractive force of the Sun is still manifested; but while the velocity of +the comet of 1680 at its perihelion is 212 miles in a second, that is, +thirteen times greater than that of the Earth, it scarcely moves ten feet in +the second when at its aphelion. This velocity is only three times greater +than that of water in our most sluggish European rivers, and equal only to +half that which I have observed in the Cassiquiare, a branch of the Orinoco. + It is highly probable that, among the innumerable host of uncalculated or +undiscovered comets, there are many whose major axes greatly exceed that of +the comet of 1680. In order to form some idea by numbers, I do not say of +the sphere of attraction, but of the distance in space of a fixed star, or +other sun, from the aphelion of the comet of 1680 (the furthest receding +cosmical body with which we are acquainted in our solar system), it must be +remembered that, according to the most recent determinations of parallaxes, +the nearest fixed star is full 250 times further removed from our sun than +the comet in its aphelion. The comet's distance is only 44 +p 110 +times that of Uranus, while 'a' Centauri is 11,000 and 61 Cygni 31,000 times +that of Uranus, according to Bessel's determinations. + +Having considered the greatest distances of comets from the central body, it +now remains for us to notice instances of the greatest proximity hitherto +measured. Lexell and Burckhardt's comet of 1770, so celebrated on account +of the disturbances it experienced from Jupiter, has approached the Earth +within a smaller distance than any other comet. On the 28th of June, 1770, +its distance from the Earth was ony six times than of the Moon. The same +comet passed twice, viz., in 1769 and 1779, through the system of Jupiter's +four satellites without producing the slightest notable change in the +well-known orbits of these bodies. The great comet of 1680 approached at +its perihelion eight or nine times nearer to the surface of the Sun than +Lexell's comet did to that of our Earth, being on the 17th of December a +sixth part of the Sun's diameter, or seven tenths of the distance of the +Moon from that luminary. Perihelia occurring beyond the orbit of Mars can +seldom be observed by the inhabitants of the Earth, owing to the faintness +of the light of distant comets; and among those already calculated the comet +of 1729 is the only one which has its perihelion between the orbits of +Pallas and Jupiter; it was even observed beyond the latter. + +Since scientific knowledge, although frequently blended with vague and +superficial views, has been more extensively diffused through wider circles +of social life, apprehensions of the possible evils threatened by comets +have acquired more weight as their direction has become more definite. The +certainty that there are within the known planetary orbits comets which +revisit our regions of space at short intervals -- that great disturbances +have been produced by Jupiter and Saturn in their orbits, by which such as +were apparently harmless have been converted into dangerous bodies -- the +intersection of the Earth's orbit by Biela's comet -- the cosmical vapor, +which, acting as a resisting and impeding medium, tends to contract all +orbits -- the individual difference of comets, which would seem to indicate +considerable decreasing gradations in the quantity of the mass of the +nucleus, are all considerations more than equivalent, both as to number and +variety, to the vague fears entertained in early ages of the general +conflagration of the world by 'flaming swords', and stars with 'fiery +streaming hair'. As the consolatory considerations which may be derived +from the calculus of probabilities address themselves to reason and to +p 111 +meditative understanding only, and not to the imagination or to a desponding +condition of mind, modern science has been accused, and not entirely without +reason, of not attempting to allay apprehensions which it has been the very +means of exciting. It is an inherent attribute of the human mind to +experience fear, and not hope or joy, at the aspect of that which is +unexpected and extraordinary.* + + +[footnote] *Fries, 'Vorlesungen uber die Sternkunde', 1833, s. 262-267 +(Lectures on the Science of Astronomy). An infelicitously chosen instance +of the good omen of a comet may be found in Seneca, 'Nat. Quest.', vii., 17 +and 21. The philosopher thus writes of the comet: "Quem nos Neronis +principatu latissimo vidimus et qui cometis detraxit infamiam." + + +The strange form of a large comet, its faint nebulous light, and its sudden +appearance in the vault of heaven, have in all regions been almost +invariably regarded by the people at large as some new and formidable agent +inimical to the existing state of things. The sudden occurrence and short +duration of the phenomenon lead to the belief of some equally rapid +reflection of its agency in terrestrial matters, whose varied nature renders +it easy to find events that may be regarded as the fulfillment of the evil +foretold by the appearance of these mysterious cosmical bodies. In our own +day, however, the public mind has taken another and more cheerful, although +singular, turn with regard to comets; and in the German vineyards in the +beautiful valleys of the Rhine and Moselle, a belief has arisen, ascribing +to these once ill-omened bodies a beneficial influence on the ripening of +the vine. The evidence yielded by experience, of which there is no lack in +these days, when comets may so frequently be observed, has not been able to +shake the common belief in the meteorological myth of the existence of +wandering stars capable of radiating heat. + +This material taken from pages 111- 147 + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +From comets I would pass to the consideration of a far more enigmatical +class of agglomerated matter -- the smallest of all asteroids, to which we +apply the name 'aërolites', or 'meteoric stones',* when they reach our +atmosphere in a fragmentary condition. + + +[footnote] * (Much valuable information may be obtained regarding the +origin and composition of aërolites or meteoric stones in Memoirs on the +subject, by Baumbeer and other writers, in the numbers of Poggendorf's +'Annalen', from 1845 to the present time.) -- Tr. + + +If I should seem to dwell on the specific enumeration of these bodies, and +of comets, longer than the general nature of this work might warrant, I have +not done so undesignedly. The diversity existing in the individual +characteristics of comets has already been noticed. The imperfect knowledge +we possess of their physical character renders it +p 112 +diifficult in a work like the present, to give the proper degree of +circumstantiality to the phenomena, which, although of frequent recurrence, +have been observed with such various degrees of accuracy, or to separate the +necessary from the accidental. It is only with respect to measurements and +computations that the astronomy of comets has made any marked advancement, +and, consequently, a scientific consideration of these bodies must be +limited to a specification of the differences of physiognomy and +conformation in the nucleus and tail, the instances of great approximation +to other cosmical bodies, and of the extremes in the length of their orbits +and in their periods of revolution. A faithful delineation of these +phenomena, as well as of those which we proceed to consider, can only be +given by sketching individual features with the animated circumstantiality +of reality. + +Shooting stars, fire-balls, and meteoric stones are, with great probability, +regarded as small bodies moving with planetary velocity, and revolving in +obedience to the laws of general gravity in conic sections round the Sun. +When these masses meet the Earth in their course, and are attracted by it, +they enter within the limits of our atmosphere in a luminous condition, and +frequently let fall more or less strongly heated stony fragments, covered +with a shining black crust. When we enter into a careful investigation of +the facts observed at those epochs when showers of shooting stars fell +periodically in Cumana in 1799, and in North America during the years 1833 +and 1834, we shall find that 'fire-balls' can not be considered separately +from shooting stars. Both these phenomena are frequently not only +simultaneous and blended together, but they likewise are often found to +merge into one another, the one phenomenon gradually assuming the character +of the other alike with respect to the size of their disks, the emanation of +sparks, and the velocities of their motion. Although exploding smoking +luminous fire-balls are sometimes seen, even in the brightness of tropical +daylight,* equaling in size the apparent +p 113 +diameter of the Moon, innumerable quantities of shooting stars have, on the +other hand, been observed to fall in forms of such extremely small +dimensions that they appear only as moving points or 'phosphorescent +lines.'** + +[footnote] *A friend of mine, much accustomed to exact trigonometrical +measurements, was in the year 1788 at Popayan, a city which is 2 degrees 26' +north latitude, lying at an elevation of 5583 feet above the level of the +sea, and at noon, when the sun was shining brightly in a cloudless sky, saw +his room lighted up by a fire-ball. He had his back to the window at the +time, and on turning round, perceived that great part of the path traversed +by the fire-ball was still illuminated by the brightest radiance. Different +nations have had the most various terms to express these phenomena: The +Germans use the word 'Sternschnuppe', literally 'star snuff' -- an +expression well suited to the physical views of the vulgar in former times, +according to which, the lights in the firmament were said to undergo a +process of 'snuffing' or cleaning; and other nations generally adopt a term +expressive of a 'shot' or 'fall' of stars, as the Swedish 'stjernifall', the +Italian 'stella cadente', and the English 'star shoot.' In the woody +district of the Orinoco, on the dreary banks of the Cassiquiare, I heard the +natives in the Mission of Vasiva use terms still more inelegant than the +German 'star snuff.' ('Relation Historique du Voy. aux Régions Equinox.', +t. ii., p. 513.) These same tribes term the pearly drops of dew which cover +the beautiful leaves of the heliconia 'star spit.' In the Lithuanian +mythology, the imagination of the people has embodied its ideas of the +nature and signification of falling stars under nobler and more graceful +symbols. The Parcæ, 'Werpeja', weave in heaven for the new-born child its +thread of fate, attaching each separate thread to a star. When death +approaches the person, the thread is rent, and the star wanes and sinks to +the earth. Jacob Grimm, 'Deutsche Mythologie', 1843, s. 685. + + +[footnote] ** According to the testimony of Professor Denison Olmsted, of +Yale College, New Haven, Connecticut. (See Poggend., 'Annalen der Physik', +bd. xxx., s. 194.) Kepler, who excluded fire-balls and shooting stars from +the domain of astronomy, because they were, according to his views, "meteors +arising from the exhalations of the earth, and blending with the higher +ether," expresses himself, however, generally with much caution. He says: +"Stellæ cadentes sunt materia viscida inflammata. Earum aliquæ inter +cadendum absumuntur, aliquæ verè in terram cadunt, pondere suo tractæ. +Nec est dissimile vero, quasdam conglobatas esse ex materia fæculentâ, in +ipsam auram ætheream immixta: exque aëtheris regione, tractu rectilineo, +per aërem trajicere, ceu minutos competas, occultâ causa motus +utrorumque." -- Kepler, 'Epit. Astron. Copernicanæ', t. i., p. 80. + + +It still remains undertermined whether the many luminous bodies that shoot +across the sky may not vary in their nature. On my return from the +equinoctial zones, I was impressed with an idea that in the torrid regions +of the tropics I had more frequently than in our colder latitudes seen +shooting stars fall as if from a height of twelve or fifteen thousand feet; +that they were of brighter colors, and left a more brilliant line of light +in their track; but this impression was no doubt owing to the greater +transparency of the tropical atmosphere*, which enables the eye to penetrate +further into distance. + + + +[footnote] *'Relation Historique', t. i., p. 80, 213, 527. If in falling +stars, as in comets, we distinguish between the head or nucleus and the +tail, we shall find that the greater transparency of the atmosphere in +tropical climates is evinced in the greater length and brilliancy of the +tail which may be observed in those latitudes. The phenomenon is therefore +not necessarily more frequent there, because it is oftener seen and +continues longer visible. The influence exercised on shooting stars by the +character of the atmosphere is shown occasionally even in our temperate +zone, and at very small distances apart. Wartmann relates that on the +occasion of a November phenomenon at two places lying very near each other, +Geneva and Aux Planchettes, the number of the meteors counted were as 1 to +7. (Wartmann, 'Mém. sur les Etoiles filantes', p. 17.) The tail of a +shooting star (or its 'train'), on the subject of which Brandes has made so +many exact and delicate observations, is in no way to be ascribed to the +continuance of the impression produced by light on the retina. It sometimes +continues visible a whole minute, and in some rare instances longer than the +light of the nucleus of the shooting star; in which case the luminous track +remains motionless. (Gilb., 'Ann.', bd. xiv., s. 251.) This circumstance +further indicates the analogy between large shooting stars and fire-balls. +Admiral Krusenstern saw, in his voyage round the world, the train of a +fire-ball shine for an hour after the lluminous body itself had disappeared, +and scarcely move throughout the whole time. ('Reise', th. i., s. 58.) Sir +Alexander Burnes gives a charming description of the transparency of the +clear atmosphere of Bokhara, which was once so favorable to the pursuit of +astronomical observations. Bokhara is situated in 39 degrees 48' north +latitude, and at an elevation of 1280 feet above the level of the sea. +"There is a constant serenity in its atmosphere, and an admirable clearness +in the sky. At night, the stars have uncommon luster, and the Milky Way +shines gloriously in the firmament. There is also a never-ceasing display +of the most brilliant meteors, which dart like rockets in the sky; ten or +twelve of them are sometimes seen in an hour, assuming every color -- fiery +red, blue, pale, and faint. It is a noble country for astronomical science, +and great must have been the advantage enjoyed by the famed observatory of +Samarkand." (Burnes, 'Travels into Bokhara', vol. ii. (1834), p. 158.) A +mere traveler must not be reproached for calling ten or twelve shooting +stars in an hour "many," since it is only recently that we have learned, +from careful observations on this subject in Europe, that eight is the mean +number which may be seen in an hour in the field of vision of one individual +(Quetelet, 'Corresp. Mathém.', Novem., 1837, p. 447); this number is, +however, limited to five or six by that diligent observer, Olbers. (Schum., +'Jahrb.', 1838, s. 325.) + + + +p 114 +Sir Alexander Burnes likewise extols as a consequence of the purity of the +atmosphere in Bokhara the enchanting and constantly-recurring spectacle of +variously-colored shooting stars. + +The connection of meteoric stones with the grander phenomenon of fire-balls +-- the former being known to be projected from the latter with such force as +to penetrate from ten to fifteen feet into the earth -- has been proved, +among many other instances, in the falls of azzzuerolites at Barbotan, in +the Department des Landes (24th July, 1790), at Siena (16th June, 1794), at +Weston, in Connecticut, U. S. (14th December, 1807), and at Juvenas in the +Department of Ardèche (14th June, 1821). Meteoric stones are in some +instances thrown from dark clouds suddenly formed in a clear sky, and fall +with a noise resembling thunder. Whole districts have thus occasionally +been covered with thousands of fragmentary masses, of uniform character but +unequal magnitudes, that +p 115 +have been hurled from one of these moving clouds. In less frequent cases, +as in that which occurred on the 16th of September, 1843, at Kleinwenden, +near Mühilhausen, a large aërolite fell with a thundering crash while the +sky was clear and cloudless. The intimate affinity between fire-balls and +shooting stars is further proved by the fact that fire-balls, from which +meteoric stones have been thrown have occasionally been found, as at Angers, +on the 9th of June, 1822, having a diameter scarcely equal to that of the +small fire-works called Roman candles. + +The formative power, and the nature of the physical and chemical processes +involved in these phenomena are questions all equally shrouded in mystery, +and we are as yet ignorant whether the particles composing the dense mass of +meteoric stones are originally, as in comets, separated from one another +when they become luminous to our sight, or whether in the case of smaller +shooting stars, any compace substance actually falls, or, finally, whether a +meteor is composed only of a smoke-like dust, containing iron and nickel; +while we are wholly ignorant of what takes place within the dark cloud from +which a noise like thunder is often heard for many minutes before the stones +fall.* + + +[footnote] *On 'méteoric dust', see Arago, in the 'Annuaire' for 1832, p. +254. I haave very recently endeavored to show, in another work ('Asie +Centrale', t. i., p. 408). how the Scythian saga of the sacred gold, which +fell burning from heaven, and remained in the possession of the Golden Horde +of the Paralatæ (Herod., iv., 5-7), probably originated in the vague +recollection of the fall of an aërolite. The ancients had also some +strange fictions (Dio Cassius, lxxv., 1259) or silver which had fallen from +heaven, and with which it had been attempted, under the Emperor Severus, to +cover bronze coins; metallic iron was however, known to exist in meteoric +stones. (Plin., ii., 56.) The frequently-recurring expression 'lapidibus +pluit' must not always be understood to refer to falls of aërolites. In +Liv., xxv., 7, it probably refers to pumice ('rapilli') ejected from the +volcano, Mount Albanus (Monte Cavo), which was not wholly extinguished at +the time. (See Heyne, 'Opuscula Acad.', t. iii., p. 261; and my 'Relation +Hist.', t. i., p. 394.) The contest of Hercules with the Ligyans, on the +road from the Caucasus to the Hesperides, belongs to a different sphere of +ideas, being an attempt to explain mythically the origin of the round quartz +blocks in the Ligyan field of stones at the mouth of the Rhone, which +Aristotle supposes to have been ejected from a fissure during an earthquake, +and Posidonius to have been caused by the force of the waves of an inland +piece of water. In the fragments that we still possess of the play of +Æschylus, the 'Prometheus Delivered', every thing proceeds, however, in +part of the narration, as in a fall of aërolites, for Jupiter draws +together a cloud, and causes the "district around to be covered by a shower +of round stones". Posidonius even ventured to deride the geognostic myth of +the blocks and stones. The Lygian field of stones was, however, very +naturally and well described by the ancients. The district is now known as +'La Crau.' (See Guerin, 'Mesures Barométriques dans les Alpes, et +Météorologie d'Avignon', 1829, chap. xii., p. 115.) + + +p 116 +We can ascertain by measurement the enormous, wonderful, and wholly +planetary velocity of shooting stars, fire-valls and meteoric stones, and we +can gain a knowledge of what is the general and uniform character of the +phenomenon, but not of the genetically cosmical process and the results of +the metamorphoses. If meteoric stones while revolving in space are already +consolidated into dense masses,* less dense, however, +p 117 +than the mean density of the earth, they must be very small nuclei, which +surrounded by inflammable vapor or gas, form the innermost part of +fire-balls, from the height and apparent diameter of which we may, in the +case of the largest, estimate that the actual diameter varies from 500 to +about 2800 feet. + + +[footnote] *The specific weight of aërolites varies from 1.9 (Alais) to 4.3 +(Tabor). Their general density may be set down as 3, water being 1. As to +what has been said in the text of the actual diameters of fire-balls, we +must remark, that the numbers have been taken from the few measurements that +can be relied upon as correct. These give for the fire-ball of Weston, +Connecticut (14th December, 1807), only 500; for that observed by Le Roi +(10th July, 1771) about 1000 and for that estimated by Sir Charles Blagden +(18th January, 1783) 2600 feet in diameter. Brandes ('Unterhaltungen' +bd.i., s. 42) ascribes a diameter varying from 80 to 120 feet to shooting +stars, and a luminous train extending from 12 to 16 miles. There are, +however, ample optical causes for supposing that the apparent diameter of +fire-balls and shooting stars has been very much overrated. The volume of +the largest fire-ball yet observed can not be compared with that of Ceres, +estimating generally so exact and admirable treatise, 'On the Connection of +the Physical Sciences', 1835, p. 411.) With the view of elucidating what +has been stated in the text regarding the large zërolite that fell into the +bed of the River Narni, but has not again been found, I will give the +passage made known by Pertz, from the 'Chronicon Benedicti, Monachi Sancti +Andreæ in Mont Soracte', a MS. belonging to the tenth century, and +preserved in the Chigi Library at Rome. The Barbarous Latin of that age has +been left unchanged. "Anno 921, temporibus domini Johannis Decimi pape, in +anno pontificatus illius 7 visa sunt signa. Nam juxta urben Romam lapides +plurimi de cælo cadere visi sunt. In civilate quæ vocatur Narnia tam diri +ac tetri, ut nihil aliud credatur, quam de infernalibus locis deducti +essent. Nam ita ex illis lapidibus unus omnium maximum est, ut decidens in +flumen Narnus, ad mensuram unius cubiti super aquas fluminus usque hodie +videretur. Nam et ignitæita ut pene terra contingeret. AliAnno 921, +temporibus domini Johannis Decimi pape, in anno pontificatus illius 7 visa +sunt signa. Nam juxta urben Romam lapides plurimi de cælo cadere visi +sunt. In civilate quæ vocatur Narnia tam diri ac tetri, ut nihil aliud +credatur, quam de infernalibus locis deducti essent. Nam ita ex illis +lapidibus unus omnium maximum est, ut decidens in flumen Narnus, ad mensuram +unius cubiti super aquas fluminus usque hodie videretur. Nam et ignitæ ita +ut pene terra contingeret. Ali cadentes," etc. (Pertz, 'Monum. Germ. Hist. +Scriptores', t. iii., p. 715.) On the aërolites of gos Potamus, which +fell, according to the Parian Chroniccle, in the 78 1 Olympiad, see Böckh, +'Corp. Inscr. Graec', t. ii., p. 302, 320, 340; also Aristot., 'Meteor.', +i., 7 (Ideler's 'Comm.', t. i., p. 404-407); Stob., 'Eel. Phys.', i., 25, p. +508 (Heeren); Plut., 'Lys.', c. 12; Diog. Laert., ii., 10; and see, also, +subsequent notes in this work. According to a Mongolisn tradition, a black +fragment of a rock, forty feet in height, fell from heaven on a plain near +the source of the Great Yellow River in Western China. (Abel Rémusat, in +Lamétherie, 'Jour. de Phys.', 1819, Mai p. 264.) + + +The largest meteoric masses as yet known are those of Otumpa, in Chaco, and +of Bahia, in Brazil, described by Rubi de Celis as being from 7 to 7 1/2 +feet in length. The meteoric stone of gos Potamos, celebrated in antiquity, +and even mentioned in the Chronicle of the Parian Marbles, which fell about +the year in which Socrates was born, has been described as of the size of +two mill-stones, and equal in weight to a full wagon load. Notwithstanding +the failure that has attended the efforts of the African traveler, Brown, I +do not wholly relinquish the hope that, even after the lapse of 2312 years, +this Thracian meteoric mass, which it would be so difficult to destroy, may +be found, since the region in which it fell is now bcome so easy of access +to European travelers. The huge aërolite which in the beginning of the +tenth century fell into the river at Narni, projected between three and four +feet above the surface of the water, as we learn from a document lately +discovered by Pertz. It must be remarked that these meteoric bodies, +whether in ancient or modern times can only be regarded as the principal +fragments of masses that have been broken up by the explosion either of a +fire-ball of a dark cloud. + +On considering the enormous velocity with which, as has been mathematically +proved, meteoric stones reach the earth from the extremest confines of the +atmosphere, and the lengthened course traversed by fire-balls through the +denser strata of the air, it seems more than improbable that these +metalliferous stony masses, containing perfectly-formed crystals of olivine, +labradorite, and pyroxene, should in so short a period of time has been +converted from a vaporous condition to a solid nucleus. Moreover, that +which falls from meteoric masses, even where the internal composition is +chemically different, exhibits almost always the peculiar character of a +fragment, being of a prismatic or truncated pyramidal form, with broad, +somewhat curved faces, and rounded angles. But whence comes this form, +which was first recognized by Schreiber as characteristic of the 'severed' +part of a rotating planetary body? Here, as in the sphere of organic life, +all that appertains to the history of development remains hidden in +obscurity. Meteoric masses become luminous and kindle at heights which +p 118 +must be regarded as almost devoid of air, of occupied by an atmosphere that +does not even contain 1/100000th part of oxygen. The recent investigations +of Biot on the important phenomenon of twilight* have considerably lowered +the lines which had, perhaps with some degree of temerity, been usually +termed the boundaries of the atmosphere; but processes of light may be +evolved independently of the presence of oxygen, and Poisson conjectured +that aëroliteswere ignited far beyond the range of our atmosphere. +Numerical calculation and geometrical measurement are the only means by +which as in the case of the larger bodies of our solar system, we are +enabled to impart a firm and safe basis to our investigations of meteoric +stones. + + +[footnote] *Biot, 'Traité d'Astronomie Physique' (3ème éd.), 1841, t. +i., p. 149, 177, 238, 312. My lamented friend Poisson endeavored, in a +singular manner, to solve the difficulty attending an assumption of the +spontaneous ignition of meteoric stones at an elevation where the density of +the atmosphere is almost null. These are his words: "It is difficult to +attribute, as is uaually done, the incandescence of aërolites to friction +against the molecules of the atmosphere at an elevation above the earth +where the density of the air is almost null. May we not suppose that the +electric fluid, in a neutral condition, forms a kind of atmosphere, +extending far beyond the mass of our atmosphere, yet subject to terrestrial +attraction, although physically imponderable, and consequently following our +globe in its motion? According to this hypothesis, the bodies of which we +have been speaking would, on entering this imponderable atmosphere, +decompose the neutral fluid by their unequal action on the two +electricities, and they would thus be heated, and in a state of +incandescence, by becoming electrified." (Poisson, 'Rech. sur la +Probabilité des Jugements', 1837, p. 6.) + + +Although Halley pronounced the great fire-ball of 1686, whose motion was +opposite to that of the earth in its orbit,* to be a cosmical body, Chadni, +in 1794, first recognized, with ready acuteness of mind, the connection +between fire-balls and the stones projected from the atmosphere, and the +motions of the former bodies in space.** + + +[footnote] *'Philos. Transact.', vol. xxix., p. 161-163. + + +[footnote] **The first edition of Chlandni's important treatise, 'Ueber den +Ursprung der von Pallas gefundenen und anderen Eisenmassen' (On the Origin +of the masses of Iron found by Pallas, and other similar masses), appeared +two months prior to the shower of stones at Siena, and two years before +Lichtenberg stated, in the 'Güttingen Taschenbuch', that "stones reach our +atmosphere from the remoter regions of space.' Comp., also, Olbers's letter +to Benzenberg, 18th Nov., 1837, in Benzenberg's 'Treatise on Shooting +Stars', p. 186. + + +A brilliant confirmation of the cosmical origin of these phenomena has been +afforded by Denison Olmsted, at New Haven, Connecticut, who has shown on the +concurrent authority of all eye-witnesses, that during the celebrated fall +of shooting stars on the night between the 12th +p 119 +and 13th of November, 1833, the fire-balls and shooting stars all emerged +from one and the same quarter of the heavens, namely, in the vicinity of the +star 'gamma' in the constellation Leo, and did not deviate from this point, +although the star changed its apparent height and azimuth during the time of +the observation. Such an independence of the Earth's rotation shows that +the luminous body must have reached our atmosphere from 'without.' +According to Encke's computation* of the whole +p 120 +number of observations made in the United States of North America, between +the thirty-fifth and the forty-second degrees of latitude, it would appear +that all these meteors came from the same point of space in the direction in +which the Earth was moving at the time. + + +[footnote] *Encke, in Poggend., 'Annalen', bd. xxxiii. (1834), s. 213. +Arago, in the 'Annuaire' for 1836, p. 291. Two letters which I wrote to +Benzenberg, May 19 and October 22, 1837, on the conjectural precession of +the nodes in the orbit of periodical falls of shooting stars. (Benzenberg's +'Sternsch.', s. 207 and 209.) Olbers subsequently adopted this opinion of +the gradual retardation of the November phenomenon. ('Astron. Nachr.', +1838, No. 372, s. 180.) If I may venture to combine two of the falls of +shooting stars mentioned by the Arabian writers with the epochs found by +Boguslawski for the fourteenth century, I obtain the following more or less +accordant elements of the movements of the nodes: + In Oct., 902, on the night in which King Ibrahim ben Ahmed died, there +fell a heavy shower of shooting stars, "like a fiery rain;" and this year +was, therefore, called the year of stars. (Conde, 'Hist. de la Domin.' de +los Arabes', p. 346.) + On the 19th of Oct., 1202, the stars were in motion all night. "They +fell like locusts." ('Comptes Rendus', 1837, t. i., p. 294; and Fræhn, in +the 'Bull. de l'Académie de St. Pétersbourg', t. iii., p. 308.) + On the 21st Oct., O.S., 1366, "'die sequente post festum XI. millia +Virginum ab hora matutina usque ad horam primam visæ sunt quasi stellæ de +cælo cadere continuo, et in tanta multitudine, quod nemo narrare suf +ficit.'" This remarkable notice, of which we shall speak more fully in the +subsequent part of this work, was found by the younger Von Boguslawski, in +Benesse (de Horowic) de Weitmil or Weithmül, 'Chronicon Ecclesiæ +Pragensis', p. 389. This chronicle may also be found in the second part of +'Scriptores rerum Bohemicarum', by Pelzel and Dobrowsky, 1784. (Schum., +'Astr. Nachr.', Dec., 1839.) + On the night between the 9th and 10th of November, 1787, many falling +stars were observed at Manheim, Southern Germany, by Hemmer (Kämtz, +'Meteor.', th. iii., s. 237.) + After midnight, on the 12th of November, 1799, occurred the +extraordinary fall of stars at Cumana, which Bonpland and myself have +described, and which was observed over a great part of the earth. ('Relat. +Hist.', t. i., p. 519-527.) + Between the 12th and 13th of November, 1822, shooting stars, +intermingled with fire-balls, were seen in large numbers by Kloden, at +Potsdam. (Gilbert's 'Ann.', bd. lxxii., s. 291.) + On the 13th of November, 1831, at 4 o'clock in the morning, a great +shower of falling stars was seen by Captain Bérard, on the Spanish coast, +near Carthagena del Levante. ('Annuaire', 1836, p. 297.) + In the night between the 12th and 13th of November, 1833, occurred the +phenomenon so admirably described by Professor Olmsted, in North America. + In the night of the 13-14th of November, 1834, a similar fall of +shooting stars was seen in North America, although the numbers were not +quite so considerable. (Poggend., 'Annalen', bd. xxxiv., s. 129.) + On the 13th of November, 1835, a barn was set on fire by the fall of a +sporadic fire-ball, at Belley, in the Department de l'Ain. ('Annuaire', +1836, p. 296.) + In the year 1838, the stream showed itself most decidedly on the night +of the 13-14th of November. ('Astron. Nachr.', 1838, No. 372.) + + +On the recurrence of falls of shooting stars in North America, in the month +of November of the years 1834 and 1837, and in the analogous falls observed +at Bremen in 1838, a like general parallelism of the orbits, and the same +direction of the meteors from the constellation Leo, were again noticed. It +has been supposed that a greater parallelism was observable in the direction +of periodic falls of shooting stars than in those of sporadic occurrence; +and it has further been remarked, that in the periodically-recurring falls +in the month of August, as, for instance, in the year 1839, the meteors came +principally from one point between Perseus and Taurus, toward the latter of +which constellations in the Earth was then moving. This peculiarity of the +phenomenon, manifested in the retrograde direction of the orbits in November +and August, should be thoroughly investigated by accurate observations, in +order that it may either be fully confirmed or refuted. + +The heights of shooting stars, that is to say, the heights of the points at +which they begin and cease to be visible, vary exceedingly, fluctuating +between 16 and 140 miles. This important result, and the enormous velocity +of these problematical asteroids, were first ascertained by Benzenberg and +Brandes, by simultaneous observations and determinations of parallax at the +extremities of a base line of 49,020 feet in length.* + + +[footnote] *I am well aware that, among the 62 shooting stars +simultaneously observed in Silesia, in 1823, at the suggestion of Professor +Brandes some appeared to have an elevation of 183 to 240, or even 400 miles. + (Brandes, 'Unterhaltungen für Freunde der Astronomie und Physik', heft i., +s. 48. Instructive Narratives for the Lovers of Astronomy and Physics.) +But Olbers considered that all determinations for elevations beyond 120 +miles must be doubtful, owing to the smallness of the parallax. + + +The relative velocity of motion is from 18 to 36 miles in a second, and +consequently equal to planetary velocity. This planetary velocity,* as well +as the direction of the orbits +p 121 +of fire-balls and shooting stars, which has frequently been observed to be +opposite to that of the Earth, may be considered as conclusive arguments +against the hypothesis that aërolites derive their origin from the +so-called active 'lunar volcanoes.' + + +[footnote] *The planetary velocity of translation, the movement in the +orbit, is in Mercury 26.4, in Venus 19.2, and in the Earth 16.4 miles in a +second. + + +Numerical views regarding a greater or lesser volcanic force on a small +cosmical body, not surrounded by any atmosphere, must, from their nature, be +wholly arbitrary. We may imagine the reaction of the interior of a planet +on its crust ten or even a hundred times greater than that of our present +terrestrial volcanoes; the direction of masses projected from a satellite +revolving from west to east might appear retrogressive, owing to the Earth +in its orbit subsequently reaching that point of space at which these bodies +fall. If we examine the whole sphere of relations which I have touched upon +in this work, in order to escape the charge of having made unproved +assertions, we shall find that the hypothesis of the selenic origin of +meteoric stones* depends upon a number of conditions +p 122 +whose accidental coincidence could alone convert a possible into an actual +fact. + + +[footnote] *Chladni states that an Italian physicist, Paolo Maria Terzago, +on the occasion of the fall of an aërolite at Milan in 1660, by which a +Franciscan monk was killed, was the first who surmised that aërolites were +of selenic origin. He says, in a memoir entitled 'Musæum Septalianum, +Manfredi Septalæ, Patricii Mediolanensis, industrioso labore constructum' +(Tortona, 1664, p. 44), "Labant philosophorum mentes sub horum lapidum +ponderibus; ni dicire velimus, lunan terram alteram, sine mundum esse, ex +cujus montibus divisa frustra in inferiorem nostrum hunc orben dela bantur." + Without any previous knowledge of this conjecture, Olbers was led, in the +year 1795 (after the celebrated fall at Siena on the 16th of June, 1794), +into an investigation of the amount of the initial tangential force that +would be requisite to bring to the Earth masses projected from the Moon. +This ballistic problem occupied, during ten or twelve years, the attention +of the geometricians Laplace, Biot, Brandes, and Poisson. The opinion which +was then so prevalent, but which has since been abandoned, of the existence +of active volcanoes in the Moon, where air and water are absent, led to a +confusion in the minds of the generality of persons between mathematical +possibilities and physical probabilities. Olbers, Brandes, and Chladni +thought "that the velocity of 16 to 32 miles, with which fire-balls and +shooting stars entered our atmosphere," furnished a refutation to the view +of their selenic origin. According to Olbers, it would require to reach the +Earth, setting aside the resistance of the air, an initial velocity of 8292 +feet in the second; according to Laplace, 7862; to Biot, 8282; and to +Poisson, 7595. Laplace states that this velocity is only five or six times +as great as that of a cannon ball; but Olbers has shown "that, with such an +initial velocity as 7500 or 8000 feet in a second, meteoric stones would +arrive at the surface of our earth with a velocity of only 35,000 feet (or +1.53 German geographical mile). But the measured velocity of meteoric +stones averages five such miles, or upward of 114,000 feet to a second; and, +consequently, the original velocity of projection from the Moon must be +almost 110,000 feet, and therefore fourteen times greater than Laplace +asserted." (Olbers, in Schum, 'Jahrb.', 1837, p. 52-58; and in Gehler, +'Neues Physik.' 'Wörterbuche', bd. vi., abth.3, s. 2199-2136.) If we +could assume volcanic forces to be still active on the Moon's surface, the +absence of atmospheric resistance would certainly give to their projectile +force an advantage over that of our terrestrial volcanoes; but even in +respect to the measure of the latter force (the projectile force of our own +volcanoes), we have no observations on which any reliance can be placed, and +it has probably been exceedingly overrated. Dr. Peters, who accurately +observed and measured the phenomena presented by Ætna, found that the +greatest velocity of any of the stones projected from the crater was only +1250 feet to a second. Observations on the Peak of Teneriffe, in 1798, gave +3000 feet. Although Laplace, at the end of his work ('Expos. du Syst. du +Monde', ed. de 1824, p. 399), cautiously observes, regarding aërolites, +"that in all probability they come from the depths of space," yet we see +from another passage (chap. vi., p. 233) 6that, being probably unacquainted +with the extraordinary planetary velocity of meteoric stones, he inclines to +the hypothesis of their lunar origin, always, however, assuming that the +stones projjected from the Moon "become satellites of our Earth, describing +around it more or less eccentric orbits, and thus not reaching its +atmosphere until several or even many revolutions have been accomplished." +As an Italian at Tortona had the fancy that aërolites came from the Moon, +so some of the Greek philosophers thought they came from the Sun. This was +the opinion of Diogenes Laertius (ii., 9) regarding the origin of the mass +that fell at "gos Potamos (see note, p. 116). Pliny, whose labors in +recording the opinions and statements of preceding writers are astonishing, +repeats the theory, and derides it the more freely, because he, with earlier +writers (Diog. Laert., 3 and 5, p. 99, Hübner), accuses Anaxagoras of +having predicted the fall of aërolites from the +Sun: "Celebrant Græci Anaxagoram Clazomenium Olympiadis septuagesimæ +octavæ secundo anno prædixisse cælestium litterarum scientia quibus +diebus saxum casurum esse e sole, idque factum interdia in Thraciæ parte ad +gos flumen. Quod si quis prædictum credat, simul fateatur necesse est, +majoris miraculi divinitatem Anaxagoræ fuisse, solvique rerum naturæ +intellectum, et confundi omnia, si aut ipse Sol lapis esse aut unquam +lapidem in eo fuisse credatur; decidere tamen crebro non erit dubium." The +fall of a moderate-sized stone, which is preserved in the Gymnasium at +Abydos, is also reported to have been foretold by Anaxagoras. The fall of +aërolites in bright sunshine, and when the Moon's disk was invisible, +probably led to the idea of sun-stones. Moreover, according to one of the +physical dogmas of Anaxagoras, which brought on him the persecution of the +theologians (even as they have attacked the geologists of our own times), +the Sun was regarded as "a molten fiery mass" ([Greed words]). In +accordance with these views of Anaxagoras, we find Euripides, in 'Phaëton', +terming the Sun "a golden mass;" that is to say, a fire-colored, +brightly-shining matter, but not leading to the inference that aërolites +are golden sun-stones. (See note to page 115.) Compare Valckenaer, +'Diatribe in Eurip. perd. Dram. Reliquias', 1767, p. 30. Diog. Laert., ii., +40. Hence, among the Greek philosophers, we find four hypotheses regarding +the origin of falling stars: a telluric origin from ascending exhalations; +masses of stone raised by hurricane (see Aristot., 'Meteor., lib. i., cap. +iv., 2-13, and cap. vii., 9); a solar origin; and, lastly, an origin in the +regions of space, as heavenly bodies which had long remained invisible. +Respecting this last opinion, which is that of Diogenes of Apollonia, and +entirely accords with that of the present day, see pages 124 and 125. It is +worthy of remark, that in Syria, as I have been assured by a learned +Orientalist, now resident at Smyrna, Andrea de Nericat, who instructed me in +Persian, there is a popular belief that aërolites chiefly fall on clear +moonlight nights. The ancients, on the contrary, especially looked for +their fall during lunar eclipses. (See Pliny, xxxvii., 10, p. 164. +Solinus, c. 37. Salm., 'Exere.', p. 531; and the passages collected by +Ukert, in his 'Geogr. der Griechen und Römer', th. ii., 1, s. 131, note +14.) On the improbability that meteoric masses are formed from +metal-dissolving gases, which, according to Fusinieri, may exist in the +highest strata of our atmosphere, and previously diffused through an almost +boundless space, may suddenly assume a solid condition, and on the +penetration and misceability of gases, see my ' +Relat. Hist.', t. i., p. 525. + + +p 122 +The view of the original existence of +p 123 +small planetary masses in space is simpler, and at the same time, more +analogous with those entertained concerning the formation of other portions +of the solar system. + +It is very probable that a large number of these cosmical bodies traverse +space undestroyed by the vicinity of our atmosphere, and revolve round the +Sun without experiencing any alteration but a slight increase in the +eccentricity of their orbits, occasioned by the attraction of the Earth's +mass. We may, consequently, suppose the possibility of these bodied +remaining invisible to us during many years and frequent revolutions. The +supposed phenomenon of ascending shooting stars and fire-balls, which +Chladni has unsuccessfully endeavored to explain on the hypothesis of the +'reflection' of strongly compressed air, appears at first sight as the +consequence of some unknown tngential force propelling bodies from the +earth; but Bessel has shown by theoretical deductions, confirmed by Feldt's +carefully-conducted calculations, that, owing to the absence of any proofs +of the simultaneous occurrence of the observed disappearances, the +assumptiopn of an ascent of shooting stars was rendered wholly improbable, +and inadmissible as a result of observation.* + + +[footnote] *Bessel, in Schum., 'Astr. Nachr.', 1839, No 389 und 381, s. 222 +und 346. At the conclusion of the Memoir there is a comparison of the Sun's +longitudes with the epochs of the November phenomenon, from the period of +the first observations in Cumana in 1799, + + +The opinion advanced by Olbers that the explosion of shooting stars and +ignited fire-balls not moving in straight lines may impel meteors upward in +the manner of rockets, and influence the direction of their orbits, must be +made the subject of future researches. + +Shooting stars fall either seprately and in inconsiderable numbers, that is, +sporadically, or in swarms of many thousands. +p 124 +The latter, which are compared by Arabian authors to swarms of locusts, are +periodic in their occurrence, and move in streams, generally in a parallel +direction. Among periodic falls, the most celebrated are that known as the +November phenomenon, occurring from about the 12th to the 14th of November, +and that of the festival of St. Lawrence (the 10th of August), whose "fiery +tears" were noticed in former times in a church calendar of England, no less +than in old traditionary legends, as a meteorological event of constant +recurrence.* + +[footnote] *Dr. Thomas Forster ('The Pocket Encyclopedia of Natural +Phenomena' 1827, p. 17) states that a manuscript is preserved in the library +of Christ's College, Cambridge,** written in the tenth century by a monk, +and entitled 'Ephemerides Rerum Naturalium', in which the natural phenomena +for each day of the year are inscribed as, for instance, the first flowering +of plants, the arrival of birds, etc.; the 10th of August is distinguished +by the word "meteorodes." It was this indication, and the tradition of the +fiery tears of St. Lawrence, that chiefly induced Dr. Forster to undertake +his extremely zealous investigation of the August phenomena. (Quetelet, +'Correspond. Mathém.', Série III., t. i., 1837, p. 433.) + +[further footnote] **[No such manuscript is at present known to exist in +the library of that college. For this information I am indebted to the +inquiries of Mr. Cory, of Pembroke College, the learned editor of +'Hieroglyphics of Horapollo Nilous', Greek and English, 1840.] -- Tr. + + +Notwithstanding the great quantity of shooting stars and fire-balls of the +most various dimensions, which, according to Klöden, were seen to fall at +Potsdam on the night between the 12th and 13th of November, 1822, and on the +same night of the year in 1832 throughout the whole of Europe, from +Portsmouth to Orenburg on the Ural River, and even in the southern +hemisphere, as in the Isle of France, no attention was directed to the +'periodicity' of the phenomenon, and no idea seems to have been entertained +of the connection existing between the fall of shooting stars and the +recurrence of certain days, until the prodigious swarm of shooting stars +which occurred in North America between the 12th and 13th of November, 1833, +and was observed by Olmsted and Palmer. The stars fell on this occasion, +like flakes of snow, and it was calculated that at least 240,000 had fallen +during a period of nine hours. Palmer, of New Haven, Connecticut, was led, +in consequence of this splendid phenomenon, to the recollection of the fall +of meteoric stones in 1799, first described by Ellicot and myself,* and +which, by +p 125 +a comparison of the facts I had adduced, showed that the phenomenon had been +simultaneously seen in the New Continent, from the equator to New Herrnhut +in Greenland (65 degrees 14' north latitude), and between 46 degrees and 82 +degrees longitude. + + +[footnote] *Humb., 'Rel. Hist.', t. i., p. 519-527. Ellicot in the +'Transactions of the American Society', 1804, vol. vi., . 29. Arago makes +the following observations in reference to the November phenomena: "We thus +become more and more confirmed in the belief that there exists a zone +composed of millions of small bodies, whose orbits cut the plane of the +ecliptic at about the point which out Earth annually occupies between the +11th and 13th of November. It is a new planetary world beginning to be +revealed to us." ('Annuaire', 1836, p. 296.) + + +The identity of the epochs was recognized with astonishment. The stream +which had been seen from Jamaica to Boston (40 degrees 21' north latitude) +to traverse the whole vault of heaven on the 12th and 13th of November, +1833, was again observed in the United States in 1834, on the night between +the 13th and 14th of November, although on this latter occasion it showed +itself with somewhat less intensity. In Europe the periodicity of the +phenomenon has since been manifested with great regularity. + +Another and a like regularly recurring phenomenon is that noticed in the +month of August, the meteoric stream of St. Lawrence, appearing between the +9th and 14th of August. Muschenbrock,* as early as in the middle of the +last century, drew attention to the frequency of meteors in the month of +August' but their certain periodic return about the time of St. Lawrence's +day was first shown by Quetelet, Olbers, and Benzenberg. + + +[footnote] *Compare Muschenbroek, 'Introd. ad Phil. Nat.', 1762, t. ii., p. +1061; Howard, 'On the Climate of London', vol. ii., p. 23, observations of +the year 1806; seven years, therefore aftr the earliest observations of +Brandes (Benzenberg, 'über Sternschnuppen', s. 240-244); the August +observations of Thomas Forster, in Quetelet, op. cit., p. 438-453; those of +Adolph Erman, Boguslawski, and Kreil, in Schum., 'Jahrb.', 1838, s. 317-330. + Regarding the point of origin in Perseus, on the 10th of August, 1839, see +the accurate measurements of Bessel and Erman (Schum., 'Astr. Nachr.', No. +385 und 428); but on the 10th of August, 1837, the path does not apper to +have been retrograde; see Arago in 'Comptes Rendus', 1837, t. ii., p. 183. + + +We shall, no doubt, in time, discover other periodically appearing streams,* +probably about the 22d to the +p. 126 +25th of April, between the 6th and 12th of December, and, to judge by the +number of true falls of aërolites enumerated by Capocci, also between the +27th and 29th of November, of about the 17th of July. + +[footnote] *On the 25th of April, 1095, "innumerable eyes in France saw +stars falling from heaven as thickly as hail" ('ut grando, nisi lucerent, +pro densitate putaretur'; Baldr., p. 88), and this occurrence was regarded +by the Council of Clermont as indicative of the great movement in +Christendom. (Wilken, 'Gesch. der Kreuzzüge', bd. i., s. 75.) On the 25th +of April, 1800, a great fall of stars was observed in Virginia and +Massachusetts; it was "a fire of rockets that lasted two hours." Arago was +the first to call attention to the "trainée d'asteroïdes," as a recurring +phenomenon. ('Annuaire', 1836, p. 297.) The falls of aërolites in the +beginning of the month of December are also deserving of notice. In +reference to their periodic recurrence as a meteoric stream, we may mention +the early observation of Brandes on the night of the 6th and 7th of +December, 1798 (when he counted 2000 falling stars), and very probably the +enormous fall of aërolites that occurred at the Rio Assu, near the village +of Macao, in the Brazils, on the 11th of December, 1836. (Brandes, +'Unterhalt. für Freunde der Physik', 1825, heft i., s. 65, and 'Comptes +Rendus', t. v., p. 211.) Capocci, in the interval between 1809 and 1839, a +space of thirty years, has discovered twelve authenticated cases of +aërolites occurring between the 27th and 29th of November, besides others +on the 13th of November, the 10th of August, and the 17th of July. +('Comptes Rendus', t. xi., p. 357.) It is singular that in the portion of +the Earth's path corresponding with the months of January and February, and +probably also with March, no 'periodic' streams of falling stars of +aërolites have as yet been noticed; although when in the South Sea in the +year 1803, I observed on the 15th of March a remarkably large number of +falling stars, and they were seen to fall as in a swarm in the city of +Quito, shortly before the terrible earthquake of Riobamba on the 4th of +February, 1797. From the phenomena hitherto observed, the following epochs +seem especially worthy of remark: +22d to the 25th of April. +17th of July (17th to the 26th of July?). (Quet., 'Corr.', 1837, p. 435.) +10th of August. +12th to the 14th of November. +27th to the 29th of November. +6th to the 12th of December. +When we consider that the regions of space must be occupied by myriads of +comets, we are led by analogy, notwithstanding the differences existing +between isolated comets and rings filled with asteroids, to regard the +frequency of these meteoric streams with less astonishment than the first +consideration of the phenomenon would be likely to excite. + + +Although the phenomena hitherto observed appear to have been independent of +the distance from the pole, the temperature of the air, and other climatic +relations, there is, however, one perhaps accidentally coincident phenomenon +which must not be wholly disregarded. The Northern Light, the Aurora +Borealis, was unusually brilliant on the occurrence of the Borealis, was +unusually brilliant on the occurrence of the splendid fall of meteors of the +12th and 13th November, 1833, described by Olmsted. It was also observed at +Bremen in 1838, where the periodic meteoric fall was, however, less +remarkable than at Richmond, near London. I have mentioned in another work +the singular fact observed by Admiral Wrangel, and frequently confirmed to +me by himself,* that when he +p 127 +was on the Siberian coast of the Polar Sea, he observed, during an Aurora +Borealis, certain portions of the vault of heaven which were not +illuminated, light up and continue luminous whenever a shooting star passed +over them. + + +[footnote] *Ferd. v. Wrangle, 'Reise längs der Nordküste von Sibirien in +den Jahren', 1820-1824, th. ii., s. 259. Regarding the recurrence of the +denser swarm of the November stream after an interval of thirty-three years, +see Olbers, in 'Jahrb.', 1837, s. 280. I was informed in Cumana that +shortly before the fearful earthquake of 1766, and consequently thirty-three +years (the same interval) before the great fall of stars on the 11th and +12th of November, 1799, a similar fiery manifestation had been observed in +the heavens. But it was on the 21st of October, 1766, and not in the +beginning of November, that the earthquake occurred. Possibly some traveler +in Quito may yet be able to ascertain the day on which the volcano of +Cayambe, which is situated there, was for the space of an hour enveloped in +falling stars, so that the inhabitants endeavored to appease heaven by +religious processions. ('Relat. Hist.', t. i., chap. iv., p 307; chap. x., +p. 520 and 527.) + + +The different meteoric streams, each of which is composed of myriads of +small cosmical bodies, probably intersect our Earth's orbit in the same +manner as Biela's comet. According to this hypothesis, we may represent to +ourselves these asteroid-meteors as composing a closed ring or zone, within +which they all pursue one common orbit. The s aller planets between Mars +and Jupiter present us if we except Pallas with an analogous relation in +their constantly intersecting orbits. As yet, however, we have no certain +knowledge as to whether changes in the periods at which the stream becomes +visible, or the 'retardations' of the phenomena of which I have already +spoken, indicate a regular precession of oscillation of the nodes -- that is +to say, of the points of intersection of the Earth's orbit and of that of +the ring; or whether this ring or zone attains so considerable a degree of +breadth from the irregular grouping and distances apart of the small bodies, +that it requires several days for the Earth to traverse it. The system of +Saturn's satellites shows us likewise a group of immense width, composed of +most intimately-connected cosmical bodies. In this system, the orbit of the +outermost (the seventh) satellite has such a vast diameter, that the Earth, +in her revolution round the Sun, requires three days to traverse an extent +of space equal to this diameter. If, therefore, in one of these rings, +which we regard as the orbit of a periodical stream, the asteroids should be +so irregularly distributed as to consist of but few groups sufficiently +dense to give rise to these phenomena, we may easily understand why we so +seldom witness such glorious spectacles as those exhibited in the November +months of 1799 and 1833. The acute mind of Olbers led him almost to predict +that the next appearance of the phenomenon of shooting stars and fire-balls +intermixed, falling like flakes of snow, would not recur until between the +12th and 14th of November, 1867. + +p 128 +The stream of the November asteroids has occasionally only been visible in a +small section of the Earth. Thus, for instance, a very splendid 'meteoric +shower' was seen in England in the year 1837, while a most attentive and +skillful observer at Braunsberg, in Prussia only saw on the same night, +which was there uninterruptedly clear, a few sporadic shooting stars fall +between seven o'clock in the evening and sunrise the next morning. Bessel* +concluded from this "that a dense group of the bodies composing the great +ring may have reached that part of the Earth in which England is situated, +while the more eastern districts of the Earth might be passing at the time +through a part of the meteoric ring proportionally less densely studded with +bodies." + + +[footnote] *From a letter to myself, dated Jan. 24th, 1838. The enormous +swarm of falling stars in November, 1799, was almost exclusively seen in +America, where it was witnessed from New Herrnhut in Greenland to the +equator. The swarms of 1831 and 1832 were visible only in Europe, and those +of 1833 and 1834 only in the United States of North America. + + +If the hypothesis of a regular progression or oscillation of the nodes +should acquire greater weight, special interest will be attached to the +investigation of older observations. The Chinese annals, in which great +falls of shooting stars, as well as the phenomena of comets, are recorded, +go back beyond the age of Tyrtæs, or the second Messenian war. They give a +description of two streams in the month of March, one of which is 687 years +anterior to the Christian era. Edward Biot has observed that among the +fifty-two phenomena which he has collected from the Chinese annals, those +that were of most frequent recurrence are recorded at periods nearly +corresponding with the 20th and 22d of July, O.S., and might consequently be +identical with the stream of St. Lawrence's day, taking into account that it +has advanced since the epochs* indicated. + + +[footnote] *Lettre de M. Edouard Biot à M. Quetelet, sur les anciennes +apparitions d'Etoiles Filantes en Chine, in the 'Bull. de l'Académie de +Bruxelles', 1843, t. x., No. 7, p. 8. On the notice from the 'Chronicon +Ecclesiæ Pragensis', see the younger Boguslawski, in Poggend., 'Annalen', +bd. xlviii., s. 612. + + +If the fall of shooting stars of the 21st of October, 1366, O.S. (a notice +of which was found by the younger Von Boguslawski, in Benessius de Horowic's +'Chronicon Ecclesiæ Pragensis'), be identical with our November phenomenon, +although the occurrence in the fourteenth century was seen in broad +daylight, we find by the precession in 477 years that this system of +meteors, or, rather, its common center of gravity, must describe +p 129 +a retrograde orbit round the Sun. It also follows, from the views thus +developed, that the non-appearance, during certain years, in any portion of +the Earth, of the two streams hitherto observed in November and about the +time of St. Lawrence's day, must be ascribed either to an interruption in +the meteoric ring, that is to say, to intervals occurring between the +asteroid groups, or, according to Poisson to the action of the larger +planets* on the form and position of this annulus. + + +[footnote] *"It appears that an apparently inexhaustible number of bodies, +too small to be observed, are moving in the regions of space, either around +the Sun or the planets, or perhaps even around their satellites. It is +supposed that when these bodies come in contact with our atmosphere, the +difference between their velocity and that of our planet is so great, that +the friction which they experience from their contact with the air heats +them to incandescence, and sometimes causes their explosion. If the group +of falling stars form an annulus around the Sun, its velocity of circulation +may be very different from that of our Earth; and the displacements it may +experience in space, in consequence of the actions of the various planets, +may render the phenomenon of its intersecting the planes of the ecliptic +possible at some epochs, and altogether impossible at others." -- Poisson, +'Recherches sur la Probabilité des Jugements', p. 306, 307. + + +The solid masses which are observed by night to fall to the earth from +fire-balls, and by day generally when the sky is clear, from a cark small +cloud, are accompanied by much candescence. They undeniably exhibit a great +degree of general identity with respect to their external form, the +character of their crust, and the chemical composition of their principal +constituents. These characteristics of identity have been observed at all +the different epochs and in the most various parts of the earth in which +these meteoric stones have been found. This striking and early-observed +analogy of physiognomy in the denser meteoric masses is, however, met by +many exceptions regarding individual points. What differences, for +instance, do we not find between the malleable masses of for instance, do we +not find between the malleable masses of iron of Hradeschina in the district +of Agram, those from the shores of the Sisim in the government of Jeniseisk, +rendered so celebrated by Pallas, or those which I brought from Mexico,* all +of which contain 96 per cent. of iron, from the aërolites of Siena, in +which the iron scarcely amounts to 2 per cent., or the earthy aërolite of +Alais (in the Department du Gard), which broke up in water, or, lastly, from +those of Jonzac and Javenas, which contained no metallic iron, but presented +a +p 130 +mixture of oryctognostically distinct crystalline compoonents! + + +[footnote] *Humboldt, 'Essai Politique sur la Nouv. Espagne' (2de édit.), +t. iii. p. 310. + + +These differences have led mineralogists to separate these cosmical masses +into two classes, namely, those containing nickelliferous meteoric iron, and +those consisting of fine or coarsely-granular meteoric dust. The crust or +rind of aërolites is peculiarly characteristic of these bodies, being only +a few tenths of a line in thickness, often glossy and pitch-like, and +occasionally veined.* + + +[footnote] *The peculiar color of their crust was observed even as early as +in the time of Pliny (ii., 56 and 58): "colore adusto." The phrase +"lateribus pluisse" seems also to refer to the burned outer surface of +aërolites. + + +There is only one instance on record, as far as I am aware (the aërolite of +Chantonnay, in La Vendée), in which the rind was absent, and this meteor, +like that of Juvenas, presented likewise the peculiarity of having pores and +vesicular cavities. In all other cases the black crust is divided from the +inner light-gray mass by as sharply-defined a line of separation as is the +black leaden-colored investment of the white granit blocks* which I brought +from the cataracts of the Orinoco, and which are also associated with many +other cataracts, as, for instance, those of the Nile and of the Congo River. + + + +[footnote] * Humb., 'Rel. Hist.', t. ii., chap xx., p. 299-302. + + +The greatest heat employed in our porcelain ovens would be insufficient to +produce any thing similar to the crust of meteoric stones, whose interior +remains wholly unchanged. Here and there, facts have been observed which +would seem to indicate a fusion together of the meteoric fragments; but, in +general, the character of the aggregate mass, the absence of compression by +the fall, and the inconsiderable degree of heat possessed by these bodies +when they reach the earth, are all opposed to the hypothesis of the interior +being in a state of fusion during their short passage from the boundary of +the atmosphere to our Earth. + +The chemical elements of which these meteoric masses consist, and on which +Berzelius has thrown so much light, are the same as those distributed +throughout the earth's crust, and are fifteen in number, namely, iron, +nickel, cobalt, manganese, chromium, copper, arsenic, zinc, potash, soda, +sulphur, phosphorus, and carbon, constituting altogether nearly one third of +all the known simple bodies. Notwithstanding this similarity with the +primary elements into which inorganic bodies are chemically reducible, the +aspect of aërolites, owing to the mode in which their constituent parts are +compounded, presents, generally, some features foreign to our telluric rocks +and minerals. The pure native iron, which is almost always +p 131 +found incorporated with aërolites, imparts to them a peculiar, but not +consequently, a 'selenic' character; for in other regions of space, and in +other cosmical bodies besides our Moon, water may be wholly absent, and +processes of oxydation of rare occurence. + +Cosmical gelatinous vesicles, similar to the organic 'nostoc' (masses which +have been supposed since the Middle Ages to be connected with shooting +stars), and those pyrites of Sterlitamak, west of the Uralian Mountains, +which are said to have constituted the interior of hailstones,* must both be +classed among the mythical fables of meteorology. + + +[footnote] *Gustav Rose, 'Reise nach dem Ural', bd. II., s. 202. + + +Some few aërolites, as those composed of a finely granular tissue of +olivine, augite, and labradorite blended together* (as the meteoric stone +found at Juvenas, in the Department de l'Ardèche, which resembled +dolorite), are the only ones, as Gustav Rose has remarked, which have a more +familiar aspect. + + +[footnote] *Gustav Rose, in Poggend., 'Ann.', 1825, bd. iv., x. 173-192. +Rammelsberg, 'Erstes Suppl. zum chem. Handwörterbuche der Mineralogie', +1843, s. 102. "It is," says the clear-minded observer Olbers, "a remarkable +but hitherto unregarded fact, that while shells are found in secondary and +tertiary formations, no 'fossil meteoric stones' have as yet been +discovered. May we conclude from this circumstance that previous to the +present and last modification of the earth's surface no meteoric stones fell +on it, although at the present time it appears probable, from the researches +of Schreibers, that 700 fall annually?" (Olbers, in Schum., 'Jahrb.', 1838, +s. 329.) Problematical nickelliferous masses of native iron have been found +in Northern Asia (at the gold-washing establishment at Petropawlowsk, eighty +miles southeast of Kusnezk), imbedded thirty-one feet in the ground, and +more recently in the Western Carpathians (the mountain chain of Magura, at +Szlanicz), both of which are remarkably like meteoric stones. Compart +Erman, 'Archiv für wissenschaftliche Kunde von Russland', bd. i., s. 315, +and Haidinger, 'Bericht über Szlaniczer Schürfe in Ungarn.' + + +These bodiescontain, for instance, crystalline substances, perfectly similar +to those of our earth's crust; and in the Siberian mass of meteoric iron +investigated by Pallas, the olivine only differs from common olivine by the +absence of nickel, which is replaced by the oxyd of tin.* + + +[footnote] *Berzelius, 'Jahresber.', bd. xv., s. 217 und 231. Rammelsberg, +'Handwörterb., abth. ii., s. 25-28. + + +As meteoric olivine, like our basalt, contains from 47 to 49 per cent. of +magnesia, constituting, according to Berzelius, almost the half of the +earthy components of meteoric stones, we can not be surprised at the great +quantity of silicate of magnesia found in these cosmical bodies. If the +zërolite of Juvenas contain separable crystals of augite and labradorite, +the numerical relation of the constituents +p 132 +render it at least probable that the meteoric masses of Chateau-Renard may +be a compound of diorite, consisting of hornblende and albite, and those of +Blansko and Chantonnay compounds of hornblende and labradorite. The proofs +of the telluric and atmospheric origin of aUerolites, which it is attempted +to base upon the oryctognostic analogies presented by these bodies, do not +appear to me to possess any great weight. + +Recalling to mind the remarkable interview between Newton and Conduit at +Kensington,* I would ask why the elementary substances that compose one +group of cosmical bodies, or one planetary system, may not, in a great +measure, be identical? + +[footnote] * "Sir Isaac Newton said he took all the planets to be composed +of the same matter with the Earth, viz., earth, water, and stone, but +variously connected." -- Turner, 'Collections for the History of Grantham, +containing authentic Memoirs of Sir Isaac Newton', p. 172. + + +Why should we not adopt this view, since we may conjecture that these +planetary bodies, like all the larger or smaller agglomerated masses +revolving round the sun, have been thrown off from the once far more +expanded solar atmosphere, and been formed from vaporous rintgs describing +their orbits round the central body? We are not, it appears to me, more +justified in applying the term telluric to the nickel and iron, the olivine +and pyroxene (augite), found in meteoric stones, than in indicating the +German plants which I found beyond the Obi as European species of the flora +of Northern Asia. If the elementary substances composing a group of +cosmical bodies of different magnitudes be identical, why should they not +likewise, in obeying the laws of mutual attraction, blend together under +definite relations of mixture, composing the white glittring snow and ice in +the polar zones of the planet Mars, or constituting in the smaller cosmical +masses mineral bodies inclosing crystals of olivine, augite, and +labradorite? Even in the domain of pure conjecture we should not suffer +ourselves to be led away by unphilosophical and arbitrary views devoid of +the support of inductive reasoning. + +Remarkable obscurations of the sun's disk, during which the stars have been +seen at mid-day (as, for instance, in the obscuration of 1547, which +continued for three days, and occurred about the time of the eventful battle +of Mühlberg), can not be explained as arising from volcanic ashes or mists, +and were regarded by Kepler as owing either to a 'materia cometica', or to a +black cloud formed by the sooty exhalations of the solar body. The shorter +obscurations of 1090 and 1203, which continued, the one only three, and the +other six +p 133 +hours, were supposed by Chladni and Schnurrer to be occasioned by the +passage of meteoric masses before the sun's disk. Since the period that +streams of meteoric shooting stars were first considered with reference to +the direction of their orbit as a closed ring, the epochs of these +mysterious celestial phenomena have been observed to present a remarkable +connection with the regular recurrence of swarms of shooting stars Adolph +Erman has evinced great acuteness of mind in his accurate investigation of +the facts hitherto observed on this subject, and his researches have enabled +him to discover the connection of the sun's conjunction with the August +asteroids on the 7th of February, and with the November asteroids on the +12th of May, the latter period corresponding with the days of +St. Mamert (May 11th), St. Pancras (May 12th), and St. Servatius (May 13th), +which according to popular belief, were accounted "cold days."* + + +[footnote] Adolph Erman, in Poggend., 'Annalen', 1839, bd. xlviii., s. +582-601. Biot had previously thrown doubt regarding the probability of the +November stream reappearing in the beginning of May ('Comptes Rendus', 1836, +t. ii., p. 670). Mädler has examined the mean depression of temperature on +the three ill-named days of May by Berlin observations for eighty-six years +('Verhandl. des Vereins zur Bedförd, des Gartenbaues', 1834, s. 377), and +found a retrogression of temperature amounting to 2.2 degrees Fahr. from the +11th to the 13th of May, a period at which nearly the most rapid advance of +heat takes place. It is much to be desired that this phenomenon of +depressed temperature, which some have felt inclined to attribute to the +melting of the ice in the northeast of Europe, should be also investigated +in very remote spots, as in America, or in the southern hemisphere. (Comp. +'Bull. de l'Acad. Imp. de St. Pétersbourg', 1843, t. i., No. 4.) + + +The Greek natural philosophers, who were but little disposed to pursue +observations, but evinced inexhaustible fergility of imagination in giving +the most various interpretation of half-perceived facts, have, however, left +some hypotheses regarding shooting stars and meteoric stones which +strikingly accord with the views now almost universally admitted of the +cosmical process of these phenomena. "Falling stars," says Plutarch, in his +life of Lysander,* are, according to the opinion of some physicists, not +eruptions of the ethereal fire extinguished in the air immediately after its +ignition, nor yet an inflammatory combustion of the air, which is dissolved +in large quantities in the upper regions of space, but these meteors are +rather a fall of celestial bodies, which, in consequence of a certain +intermission in the rotatory force, and by the impulse of some irregular +movements, have been hurled down not only to the inhabited portions of the +Earth, but also beyond it into the great ocean, where we can not find them." + + +[footnote] *Plut., 'Vitæ par, in Lysandro', cap. 22. The statement of +Damachos (Daïmachos), that for seventy days continuously there was a fiery +cloud seen in the sky, emitting sparks like falling stars, and which then, +sinking nearer to the earth, let fall the stone of Ægos Potamos, "which, +however, was only a small part of it," is extremely improbable, since the +direction and velocity of the fire-cloud would in that case of necessity +have to remain for so many days the same as those of the earth; and this, in +the fire-ball of the 19th of July, 1686, described by Halley ('Trans.', vol. +xxix., p. 163), lasted only a few minutes. It is not altogether certain +whether Daïmachos, the writer, [Greek words], was the same person as +Daïmachos of Platæa, who was sent by Selencus to India to the son of +Androcottos, and who ws charged by Strabo with being "a speaker of lies" (p. +70, Casaub.). From another passage of Plutarch ('Compar. Solonis c. Cop.', +cap. 5) we should almost believe that he was. At all events, we have here +only the evidence of a very late author, who wrote a century and a half +after the fall of aërolites occurred in Thrace, and whose authenticity is +also doubted by Plutarch. + + +Diogenes of Apollonia* expresses himself still more explicitly. + + +[footnote] *Stob., ed. Heeren, i., 25, p. 508; Plut., 'de plac. Philos.', +ii., 13. + + +According to his views, "Stars that are 'invisible', and, consequently, have +no name, move in space together with those that are visible. These +invisible stars frequently fall burning at Ægos Potamos." The Apollonian, +who held all other stellar bodies, when luminous, to be of a pumice-like +nature, probably grounded his opinions regarding shooting stars and meteoric +masses on the doctrine of Anaxagoras the Clazomenian, who regarded all the +bodies in the universe "as fragments of rocks, which the fiery ether, in the +force of its gyratory motion, had torn from the Earth and converted into +stars." In the Ionian school, therefore, according to the testimony +transmitted to us in the views of Diogenes of Apollonia, aërolites and +stars were ranged in one and the same class; both, when considered with +reference to their primary origin, being equally telluric, this being +understood only so far as the Earth was then regarded as a central body,* +p 135 +forming all things around it in the same manner was we, according to our +present views, suppose the planets of our system to have originated in the +expanded atmosphere of another central body, the Sun. + + +[footnote] *The remarkable passage in Plut., 'de plac. Philos.', ii., 13, +runs thus: "Anaxagoras teaches that the surrounding ether is a fiety +substance, which, by the power of its rotation, tears rocks from the earth, +inflames them, and converts them into stars." Applying an ancient fable to +illustrate a physical dogma, the Clazomenian appears to have ascribed the +fall of the Nemæan Lion to the Peloponnesus from the Moon to such a +rotatory or centrifugal force. (Ælian., xii., 7; Plut., 'de Facie in Orge +Lunæ' c. 24; Schol. ex Cod. Paris., in 'Apoll. Argon.', lib. i., p. 498, +ed. Schaef., t. ii., p. 40; Meineke, 'Annal. Alex.', 1843, p. 85.) Here, +instead of stones from the Moon, we have an animal from the Moon! According +to an acute remark of Böckh, the ancient mythology of the Nemæan lunar +lion has an astronomical origin, and is symbolically connected in chronology +with the cycle of intercalation of the lunar year, with the moon-worship at +Nemæa, and the games by which it was accompanied. + + +These views must not, therefore, be confounded with what is commonly termed +the telluric or atmospheric origin of meteoric stones, nor yet with the +singular opinion of Aristotle, which supposed the enormous mass of Ægos +Potamos to have been raised by a hurricane. That rrogant spirit of +incredulity, which rejects facts without attempting to investigate them, is +in some cases almost more injurious than an unquestioning credulity. Both +are alike detrimental to the force of investigation. Notwithstanding that +for more than two thousand years the annals of different nations had +recorded falls of meteoric stones, many of which had been attested beyond +all doubt by the evidence of irreproachable eye-witnesses -- notwithstanding +the important part enacted by the Bætylia in the meteor-worship of the +ancients -- notwithstanding the fact of the companions of Cortez having see +an aërolite at Cholula which had fallen on the neighboring pyramid -- +notwithstanding that califs and Mongolian chiefs had caused swords to be +forged from recently-fallen meteoric stones -- nay, notwithstanding that +several persons had been struck dead by stones falling from heaven, as for +instance, a monk at Crema on the 4th of September, 1511, another monk at +Milan in 1650, and two Swedish sailors on board ship in 1674, yet this great +cosmical phenomenon remained almost wholly unheeded, and its intimate +connection drawn to the subject by Chladni, who had already gained immortal +renown by his discovery of the sound-figures. He who is penetrated with a +sense of this mysterious connection, and whose mind is open to deep +impressions of nature, will feel himself moved by the deepest and most +solemn emotion at the sight of every star that shoots across the vault of +heaven, no less than at the glorious spectacle of meteoric swarms in the +November phenomenon or on St. Lawrence's day. Here motion is suddenly +revealed in the midst of nocturnal rest. The still radiance of the vault of +heaven is for a moment animated with life and movement. In the mild +radiance left on the track of the shooting star, imagination pictures the +lengthened path of the meteor through the vault of heaven, +p 136 +while, every where around, the luminous asteroids proclaim the existence of +one common material universe. + +If we compare the volume of the innermost of Saturn's satellites, or that of +Ceres, with the immense volume of the Sun, all relations of magnitude vanish +from our minds. The extinction of suddenly resplendent stars in Cassiopeia, +Cygnus, and Serpentarius have already led to the assumption of other and +non-luminous cosmical bodies. We now know that the meteoric asteroids, +spherically agglomerated into small masses, revolve round the Sun, +intersect, like comets, the orbits of the luminous larger planets, and +become ignited either in the vicinity of our atmosphere or in its upper +strata. + +The only media by which we are brought in connection with other planetary +bodies, and with all portions of the universe beyond our atmosphere, are +light and heat (the latter of which can scarcely be separated from the +former),* and those mysterious powers of attraction exercised by remote +masses, according to the quantity of their constituents, upon our globe, the +ocean, and the strata of our atmosphere. + + +[footnote' *The following remarkable passage on the radiation of heat from +the fixed stars, and on their low combustion and vitality -- one of Kepler's +many aspirations -- occurs in the 'Paralipom. in Vitell. Astron. +parsOpticqa', 1604, Propos. xxxii., p. 25: "Luciis proprium est calor, +sydera omnia calefaciunt. De syderum luce claritatis ratio testatur, +calorem universorum in minori esse proportione ad calorem unius solis, quam +ut ab homine, cujus est certa caloris mensura, utrque simul percipi et +judicari possit. De cincindularum lucula tenuissima negare non potes, quin +cum calore sit. Vivunt enim et moventur, hoc auten non sine calefactione +perficitur. Sic neque putrescentium lignorum lux sui calore destituitur; +nam ipsa puetredo quidam lentus ignis est. Inest et stirpibus suus calor." +(Compare Kepler, 'Epit. Astron. Copernicanæ', 1618, t. i., lib. i., p. 35.) + + +Another and different kind of cosmical, or, rather, material mode of contact +is, however, opened to us, if we admit falling stars and meteoric stones to +be planetary asteroids. They not only act upon us merely from a distance by +the excitement of luminous or calorific vibrations, or in obedience to the +laws of mutual attraction, but they acquire an actual material existence for +us, reaching our atmosphere from the remoter regions of universal space, and +remaining on the earth itself. Meteoric stones are the only means by which +we can be brought in possible contact with that which is foreign to our own +planet. Accustomed to gain our knowledge of what is not telluric solely +through measurement, calculations, and the deductions of reason, we +experience a sentiment of astonishment at finding that we may examine, +weigh, and analyze bodies that appertain +p 137 +to the outer world. This awakens, by the power of the imagination, a +meditative, spiritual train of thought, where the untutored mind perceives +only scintillations of light in the firmament, and sees in the blackened +stone that falls from the exploded cloud nothing beyond the rough product of +a powerful natural force. + +Although the asteroid-swarms, on which we have been led, from special +predilection, to dwell somewhat at length, approximate to a certain degree, +in their inconsiderable mass and the diversity of their orbits, to comets, +they present this essential difference from the latter bodies, that our +knowledge of their existence is almost entirely limited to the moment of +their destruction, that is, to the period when, drawn within the sphere of +the Earth's attraction they become luminous and ignite. + +In order to complete our view of all that we have learned to consider as +appertaining to our solar system, which now, since the discovery of the +small planets, of the interior comets of short revolutions, and of the +meteoric asteroids, is so rich and complicated in its form, it remains for +us to speak of the ring of Zodiacal light, to which we have already alluded. + Those who have lived for many years in the zone of palms must retain a +pleasing impression of the mild radiance with which the zodiacal light, +shooting pyramidally upward, illumines a part of the uniform length of +tropical nights. I have seen it shine with an intensity of light equal to +the milky way in Sagittarius, and that not only in the rare and dry +atmosphere of the summits of the Andes, at an elevation of from thirteen to +fifteen thousand feet, but even on the boundless grassy plains, the Illanos +of Venezuela, and on the sea-shore, beneath the ever-clear sky of Cumana. +This phenomenon was often rendered especially beautiful by the passage of +light, fleecy clouds, which stood out in picturesque and bold relief from +the luminous back-ground. A notice of this aërial spectacle is contained +in a passage in my journal, while I was on the voyage from Lima to the +western coasts of Mexico: "For three or four nights (between 10ºdegrees +and 14ºdegrees north latitude) the zodiacal light has appeared in greater +splendor than I have ever observed it. The transparency of the atmosphere +must be remarkably great in this part of the Southern Ocean, to judge by the +radiance of the stars and nebulous spots. From the 14th to the 19th of +March a regular interval of three quarters of an hour occurred between the +disappearance of the sun's disk in the ocean and the first manifestation of +the zodiacal +p 138 +light, although the night was already perfectly dark. an hour after sunset +it was seen in great briliancy between Aldebaran and the Pleiades; and on +the 18th of March it attained an altitude of 39ºdegrees5'minutes. Narrow +elongated clouds are scattered over the beautiful deep azure of the distant +horizon, flitting past the zodiacal light as before a golden curtain. Above +these, other clouds are from time to time reflecting the most brightly +variegated colors. It seems a second sunset. On this side of the vault of +heaven the lightness of the night appears to increase almost as much as at +the first quarter of the moon. Toward 10 o'clock the zodiacal light +generally becomes very faint in this part of the Southern Ocean, and at +midnight I have scarcely been able to trace a vestige of it. On the 16th of +March, when most strongly luminous a faint reflection was visible in the +east." In our gloomy so-called "temperate" northern zone, the zodiacal +light is only distinctly visible in the beginning of Spring, after the +evening twilight, in the western part of the sky, and at the close of +Autumn, before the dawn of day, above the eastern horizon. + +It is difficult to understand how so striking a natural phenomenon should +have failed to attract the attention of physicists and astronomers until the +middle of the seventeenth century, or how it could have escaped the +observation of the Atabian natural philosophers in ancient Bactria, on the +euphrates, and in the south of Spain. Almost equal surprise is excited by +the tardiness of observation of the nebulous spots in Andromeda and Orion, +first described by Simon Marius and Huygens. The earliest explicit +descriptions of the zodiacal light occurs in Childrey's 'Britannia +Baconica',* in the year 1661. +p 139 + + +[footnote] *"There is another thing which I recommend to the observation of +mathematical men, which is that in February, and for a little before and a +little after that month (as I have observed several years together), about +six in the evening, when the twilight hath almost deserted the horizon, you +shall see a plainly discernible way of the twilight striking up toward the +Pleiades, and seeming almost to touch them. It is so observed any clear +night, but it is best illac nocte. There is no such way to be observed at +any other time of the year (that I can perceive), nor any other way at that +time to be perceived darting up elsewhere; and I believe it hath been, and +will be constantly visible at that time of the year; but what the cause of +it in nature should be, I can not yet imagine, but leave it to future +inquiry." (Childrey, 'Britannia Baconica', 1661, p. 183.) This is the +first view and a simple description of the phenomenon. (Cassini, +'Découverte de la Lumi dfd éleste qui paroît dans le Zodiaque', in the +'Mém. de l'Acad.', t. viii., 1730, p 276. Mairan, 'TraitéPhys de l'Aurore +Boréale', 1754, 0. 16.) In this remarkable work by Childrey there are to +be found (p. 91) very clear accounts of the epochs of maxima and minima +diurnal and annual temperatures, and of the retardation of the extremes of +the effects in meteorological processes. It is, however, to be regretted +that our Baconian-philosophy-loving author, who was Lord Henry Somerset's +chaplain, fell into the same error as Bernardin de St. Pierre, and regarded +the Earth as elongated at the poles (see p. 148). At the first he believes +that the Earth was spherical, but supposes that the uninterrupted and +increasing addition of layers of ice at both poles has changed its figure; +and that as the ice is formed from water, the quantity of that liquid is +every where diminishing. + + +The first observation of the phenomenon may have been made two or three +years prior to this period; but, notwithstanding, the merit of having (in +the spring of 1683) been the first to investigate the phenomenon in all its +relations in space is incontestably due to Dominicus Cassini. The light +which he saw at Bologna in 1668, and which was observed at the same time in +Persia by the celebrated traveler Chardin (the court astrologers of Ispahan +called this light, which had never before been observed, 'nyzek', a small +lance), was not the zodiacal light, as has often been asserted,* but the +p 140 +enormous tail of a comet, whose head was concealed in the vapory mist of the +horizon, and which, from its length and appearance, presented much +similarity to the great comet of 1843. + + +[footnote] *Dominicus Cassini ('Mém. de l'Acad.', t. viii., 1730, p. 188), +and Mairan ('Aurore Bor.', p. 16), have even maintained that the phenomenon +observed in Persia in 1668 was the zodiacal light. Delambre ('Hist. de +l'Astron. Moderne', t. ii., p. 742), in very decided trms ascribes the +discovery of this light to the celebrated traveler Chardin; but in the +'Couronnement de Soliman', and in several passages of the narrative of his +travels (éd. de Langlès. t. iv., p. 326; t. x., p. 97), he only applies +the term niazouk (nyzek), or "petite lance," to "the great and famous comet +which appeared over nearly the whole world in 1668, and whose head was so +hidden in the wewst that it could not be perceived in the horizon of +Ispahan" ('Atlas du Voyage de Chardin', Tab. iv.; from the observations at +Schiraz). The head or nucleus of the comet was, however, visible in the +Brazils and in India (Pingré, 'Cométogr.', t. ii., p. 22). Regarding the +conjectured identity of the last great comet of March, 1843, with this, +which Cassini mistook for the zodiacal light, see Schum., 'Astr. Nachr.', +1843, No. 476 and 480. In Persian, the term "nizehi âteschîn"(fiery +spears or lances) is also applied to the rays of the rising or setting sun, +in the same way as "nayâzik," according to Freytag's Arabic Lexicon, +signifies "stellæ cadentes." The comparison of comets to lances and swords +was, however, in the Middle Ages, very common in all languages. The great +comet of 1500, which was visible from April to June, was always termed by +the Italian writers of that time 'il Signor Astone' (see my 'Examen Critique +de l'Hist. de la Géographie', t. v., p. 80). All the hypotheses that have +been advanced to show that Descartes (Cassini, p. 230; Mairan, p. 16), and +even Kepler (Delambre, t. i., p. 601), were acquainted with the zodiacal +light, appear to me altogether untenable. Descartes ('Principes', iii., +art. 136, 137) is very obscure in his remarks on comets, observing that +their tails are formed "by oblique rays, which, falling on different parts +of the planetary orbs, strike the eye laterally by extraordinary +refraction," and that they might be seen morning and evening, "like a long +beam," when the Sun is between the comet and the Earth. This passage no +more refers to the zodiacal light than those in which Kepler ('Epit. Astron. +Copernicanæ', t. i., p. 57, and t. ii., p. 893) speaks of the existence of +a solar atmosphere (limbus circa solem, coma lucida), which, in eclipses of +the Sun, prevents it "from being quite night:" and even more uncertain, or +indeed erroneous, is the assumption that the "trabes quas [Greek word] +vocant" (Plin., ii., 26 and 27) had reference to the tongue-shaped rising +zodiacal light, as Cassini (p. 231, art. xxxi.) and Mairan (p. 15) have +maintained. Every where among the ancients the trabes are associated with +the bolides (ardores et faces) and other fiery meteors, and even with +long-barbed comets. (Regarding [Greek words] . see Schäfer, 'Schol. Par. +ad Apoll. Rhod.', 1813, t. ii., p. 206; Pseudo-Aristot., 'de Mundo, 2, 9; +'Comment. Alex. Joh. Philop. et Olymp. in Aristot. Meteor.', lib. i., cap. +vii., 3, p. 195, Ideler; Seneca, 'Nat. Quæst.', i., 1.) + + +We may conjecture, with much probability, that the remarkable light on the +elevated plains of Mexico, seen for forty nights consecutively i8n 1509, and +observed in the eastern horizon rising pyramidally from the earth, was the +zodiacal light. I found a notice of this phenomenon in an ancient Aztec +MS., the 'CodexTelleriano-Remensis',* preserved in the Royal Library at +Paris. + + +[footnote] *Humboldt, 'Monumens des Peuples Indigènes de l'Amérique', t. +ii., p. 301. The rare manuscript which belonged to the Archbishop of +Rheims, Le Tellier, contains various kinds of extracts from an Aztec ritual, +an astrological calendar, and historical annals, extending from 1197 to +1549, and embracing a notice of different natural phenomena, epochs of +earthquakes and comets (as, for instance, those of 1490 and 1529), and of +(which are important in relation to Mexican chronology) solar eclipses. In +Camargo's manuscript 'Historia de Tlascala', the light rising in the east +almost to the zenith is, singularly enough, described as "sparkling, and as +if sown with stars." The description of this phenomenon, which lasted forty +days, can not in any way apply to volcanic eruptions of Popcatepetl, which +lies very near, in the southeastery direction. (Prescott, 'History of the +Conquest of Mesico', vol. i., p. 284.) Later commentators have confounded +this phenomenon, which Montezuma regarded as a warning of his misfortunes, +with the "estrella que humeava" (literally, 'which spring forth'; Mexican +'choloa, to leap or spring forth'). With respect to the connection of this +vapor with the star Citlal Choloha (Venus) and with "the mountain of the +star" (Citialtepetl, the volcano of Orizaba), see my 'Monumens', t. ii., p. +303. + + +This phenomenon, whose primordial antiquity can scarcely be doubted, and +which was first noticed in Europe by Childrey and Dominicus Cassini, is not +the luminous solar atmosphere itself, since this can not, in accordance with +mechanical laws, be more compressed than in the relation of 2 to 3, and +consequently can not be diffused beyond 9/20ths of Mercury's heliocentric +distance. These same laws teach us that the altitude of the extreme +boundaries of the atmosphere of a cosmical +p 141 +body above its equator, that is to say, the point at which gravity and +centrifugal force are in equilibrium, must be the same as the altitude at +which a satellite would rotate round the central body simultaneously with +the diurnal revolution of the latter.* + + +[footnote] *Laplace, 'Expos. du Syst. du Monde', p. 270; 'Mécanique +Céleste', t. ii., p. 169 and 171; Schubert, 'Astr.', bd. iii., § 206. + + +This limitation of the solar atmosphere in its present concentrated +condition is especially remarkable when we compare the central body of our +system with the nucleus of other nebulous stars. Herschel has discovered +several, in which the radius of the nebulous matter surrounding the star +appeared at an angle of 150". On the assumption that the parallax is not +fully equal to 1", we find that the outermost nebulous layer of such a star +must be 150 times further from the central body than our Earth is from the +Sun. If, therefore, the nebulous star were to occupy the place of our Sun, +its atmosphere would not only include the orbit of Uranus, but even extend +eight times beyond it.• + + +[footnote] *Arago, in the 'Annuaire', 1842, p. 408. Compare Sir John +Herschel's considerations on the volume and faintness of light of planetary +nebulæ, in Mary Somerville's 'Connection of the Physical Sciences', 1835, +p. 108. The opinion that the Sun is a nebulous star, whose atmosphere +presents the phenomenon of zodiacal light, did not originate with Dominicus +Cassini, but was first promulgated by Mairan in 1730 ('Traité de l'Aurore +Bor.', p. 47 and 263; Arago, in the 'Annuaire', 1842, p. 412). It is a +renewal of Kepler's views. + + +Considering the narrow limitation of the Sun's atmosphere, which we have +just described, we may with much probability regard the existence of a very +compressed annulus of nebulous matter,* revolving freely in space between +the orbits of Venus and Mars, as the material cause of the zodiacal light. + + +[footnote] *Cominicus Cassini was the first to assume, as did subsequently +Laplace, Schubert, and Poisson, the hypothesis of a separate ring to explain +the form of the zodiacal light. He says distinctly, "If the orbits of +Mercury and Venus were visible (throughout their whole extent), we should +invariably observe them with the same figure and in the same position with +regard to the Sun, and at the same time of the year with the zodiacal +light." ('Mém. de l'Acad.', t. viii., 1730, p. 218, and Biot, in the +'Comptes Rendus', 1836, t. iii., p. 666.) Cassini believed that the +nebulous ring of zodiacal light consisted of innumerable small planetary +bodies revolving round the Sun. He even went so far as to believe that the +fall of fire-balls might be connected with the passage of the Earth through +the zodiacal nebulous ring. Olmsted, and especially Biot (op. cit., p. +673), have attempted to establish its connection with the November +phenomenon -- a connection which Olbers doubts. (Schum., 'Jahrb.', 1837, s. +281.) Regarding the question whether the place of the zodiacal light +perfectly coincides with that of the Sun's equator, see Houzeau, in Schum., +'Astr. Nachr.', 1843, No. 492, s. 190. + + +As +p 142 +yet we certainly know nothing definite regarding its actual material +dimensions; its augmentation* by emanations from the tails of myriads of +comets that come within the Sun's vicinity; the singular changes affecting +its expansion, since it sometimes does not apper to extend beyond our +Earth's orbit; or, lastly, regarding its conjectural intimate connection +with the more condensed cosmical vapor in the vicinity of the Sun. + + +[footnote] *Sir John Herschel, 'Astron.', § 487. + + +The nebulous particles composing this ring, and revolving round the sun in +accordance with planetary laws, may either be self-luminous or receive light +from that luminary. Even in the case of a terrestrial mist (and this fact +is very remarkable), which occurred at the time of the new moon at midnight +in 1743, the phosphorescence was so intense that objects could be distinctly +recognized at a distance of more than 600 feet. + +I have occasionally been astonished in the tropical climates of south +america, to observe the variable intensity of the zodiacal light. As i +passed the nights, during many months, in the open air, on the shores of +rivers and on ilanos, i enjoyed ample opportunities of carefully examining +this phenomenon. When the zodiacal light had been most intense, i have +observed that it would be perceptibly weakened for a few minutes, until it +again suddenly shone forth in full brilliancy. In some few instances i have +thought that i could perceive -- not exactly a reddish coloration, nor the +lower portion darkened in an arc-like form, nor even a scintillation, as +mairan affirms he has observed -- but a kind of flickering and wavering of +the light.* + + +[footnote] *Arago, in the 'Annuaire', 1832, p. 246. Several physical facts +appear to indicate that, in a mechanical separation of matter into its +smallest particles, if the mass be very small in relation to the surface, +the electrical tension may increase sufficiently for the production of light +and heat. Experiments with a large concave mirror have not hitherto given +any positive evidence of the presence of radiant heat in the zodiacal light. + (Lettre de M. Matthiessen à M. Arago, in the 'Comptes Rendus', t. xvi., +1843, Avril, p. 687.) + + +Must we suppose that changes are actually in progress in the nebulous ring? +or is it not more probable that, although I could not, by my meteorological +instruments, detect any change of heat or moisture near the ground, and +small stars of the fifth and sixth magnitudes appeared to shine with equally +undiminished intensity of light, processes of condensation may be going on +in the uppermost strata of the air, by means of which the transparency, or +rather, the reflection of light, may be modified in some peculiar and +unknown manner? +p 143 +An assumption of the existence of such meteorological causes on the confines +of our atmosphere is strengthened by the "sudden flash and pulsation of +light," which, according to the acute observations of Olbers, vibrated for +several seconds through the tail of a comet, which appeared during the +continuance of the pulsations of light to be lengthened by several degrees, +and then again contracted.* + + +[footnote] *"What you tell me of the changes of light in the zodiacal +light, and of the causes to which you ascribe such changes within the +tropics, is of the greatr interest to me, since I have been for a long time +past particularly attentive, every spring, to this phenomenon in our +northern latitudes. I, too, have always believed that the zodiacal light +rotated; but I assumed (contrary to Poisson's opinion, which you have +communicated to me) that it completely extended to the Sun, with +considerably augmenting brightness. The light circle which, in total solar +eclipses, is seen surrounding the darkened Sun, I have regarded as the +brightest portion of the zodiacal light. I have convinced my self that this +light is very different in different years, often for several successive +years being very bright and diffused, while in othr years it is scarcely +perceptible. I tyhink that I find the first trace of an allusion to the +zodiacal light in a letter from Rothmann to Tycho, in which he mentions that +in the spring he has observed the twilight did not close until the sun was +24ºdegrees below the horizon. Rothmann must certainly have confounded the +disappearance of the setting zodiacal light in the vapors of the western +horizon with the actual cessation of twilight. I have failed to observe the +pulsations of the light, probably on account of the faintness with which it +appears in these countries. You are, however, certainly right in ascribing +those rapid variations in the light of the heavenly bodies, which you have +perceived in tropical climates, to our own atmosphere, and especially to its +higher regions. This is especially in the clearest weather, that these +tails exhibit pulsations, commencing from the head, as being the lowest +part, and vibrating in one or two seconds through the entire tail, which +thus appears rapidly to become some degrees longer, but again as rapidly +contracts. That these undulations, which were formerly noticed with +attention by Robert Hooke, and in more recent times by Schröter and +Chladni, 'do not actually occur in the tails of the comets', but are +produced by our atmosphere, is obvious when we recollect that the individual +parts of those tails (which are many millions of miles in length) lie 'at +very different distances' from us, and that the light from their extreme +points can only reach us at intervals of time which differ several minutes +from one another. Whether what you saw on the Orinoco, not at intervals of +seconds, but of minutes, were actual coruscations of the zodiacal light, or +whether they belonged exclusively to the upper strata of our atmosphere, I +will not attempt to decide; neither can I explain the remarkable 'lightness +of whole nights', nor the anomalous augmentation and prolongation of the +twilight in the year 1831, particularly if, as has been remarked, the +lightest part of these singular twilights did not coincide with the Sun's +place below the horizon." (From a lettr written by Dr. Olbers to myself, +and dated Bremen, Marth 26th, 1833.) + + +As, however, the separate particles of a comet's tail, measuring millions of +miles, +p 144 +are very unequally distant from earth, it is not possible, according to the +laws of the velocity and transmission of light, that we should be able, in +so short a period of time, to perceive any actual changes in a cosmical body +of such vast extent. There considerations in no way exclude the realith of +the changes that have been observed in the emanations from the more +condensed envelopes around the nucleus of a comet, nor that of the sudden +irradiation of the zodiacal light, from internal molecular motion, nor of +the increased or diminished reflection of light in the cosmical vapor of the +luminous ring, but should simply be the means of drawing our attention to +the differences existing between that which appertains to the air of heaven +(the realms of universal space) and that which belongs to the strata of our +terrestrial atmosphere. It is not possible, as well-attested facts prove, +perfectly to explain the operations at work in the much-contested upper +boundaries of our atmosphere. The extraordinary lightness of whole nights +in the year 1831, during which small print might be read at midnight in the +latitudes of Italy and the north of Germany is a fact directly at variance +with all that we know, according to the most recent and acute researches on +the crepuscular theory, and of the height of the atmosphere.* + +[footnote] *Biot, 'Traité d'Astron. Physique', 3ème éd., 1841, t. i., p. +171, 238 and 312. + + +The phenomena of light depend upon conditions still less understood, and +their variability at twilight, as well as in the zodiacal light, excite our +astonishment. + +We have hitherto considered that which belongs to our solare system -- that +world of material forms governed by the Sun -- which includes the primary +and secondary planets, comets of short and long periods of revolution, +meteoric asteroids, which move thronged together in streams, either +sporadically or in closed rings, and finally a luminous nebulous ring, that +revolves round the Sun in the vicinity of the Earth, and for which, owing to +its position, we may retain the name of zodiacal light. Every where the law +of periodicity governs the motions of these bodies, however different may be +the amount of tangential velocity, or the quantity of their agglomerated +material parts; the meteoric asteroids which enter our atmosphere from the +external regions of universal space are alone arrested in the course of +their planetary revolution, and retained within the sphere of a larger +planet. In the solar system, whose boundaries determine the attractive +force of the central body, comets are made to revolve in their elliptical +p 145 +orbits at a distance 44 times greater than that of Uranus; may, in those +comets whose nucleus appears to us, from its inconsiderable mass, like a +mere passing cosmical cloud, the Sun exercises its attractive force on the +outermost parts of the emanations radiating from the tail over a space of +many millions of miles. Central forces, therefore, at once constitute and +maintain the system. + +Our Sun may be considered as at rest when compared to all the large and +small, dense and almost vaporous cosmical bodies tht appertain to and +revolve around it; but it actually rotates around the common center of +gravity of the whole system, which occasionally falls within itself, that is +to say, remains within the material circumference of the Sun, whatever +changes may be assumed by the position of the planets. A very different +phenomenon is that presented by the translatory motion of the Sun, that is, +the progressive motion of the center of gravity of the whole solar system in +universal space. Its velocity is such* that, according to Bessel, the +relative motion of the Sun, and that of 61 Cygni, is not less in one day +than 3,336,000 geographical miles. + + +[footnote] *Bessel, in Schum., 'Jahrb. für' 1839, s. 51; probably four +millions of miles daily, in a relative velocity of at the least 3,336,000 +miles, or more than couble the velocity of revolution of the Earth in her +orbit round the Sun. + + +This change of the entire solar system would remain unknown to us, if the +admirable exactness of our astronomical instruments of measurement, and the +advancement recently made in the art of observing, did not cause our advance +toward remote stars to be perceptible, like an approximation to the objects +of a distant shore in apparent motion. The proper motion of the star 61 +Cygni, for instance, is so considerable, that it has amounted to a whole +degree in the course of 700 years. + +The amount or quantity of these alterations in the fixed stars (that is to +say, the changes in the relative position of self-luminous stars toward each +other), can be determined with a greater degree of certainty than we are +able to attach to the genetic explanation of the phenomenon. After taking +into consideration what is due to the precession of the equinoxes, and the +nutation of the earth's axis produced by the action of the Sun and Moon on +the spheroidal figure of our globe, and what may be ascribed to the +transmission of light, that is to say, to its aberration, and to the +parallax formed by the diametrically opposite position of the Earth in its +course round the Sun, we still find that there is a residual portion +p 146 +of the annual motion of the fixed stars due to the translation of the whole +solar system in universal space, and to the true proper motion of the stars. + The difficult problem of numerically separating these two elements, the +true and the apparent motion, has been effected by the careful study of the +direction of the motion of certain individual stars, and by the +consideration of the fact that, if all the stars were in a state of absolute +rest, they would appear perspectively to recede from the point in space +toward which the Sun was directing its course. But the ultimate result of +this investigation, confirmed by the calculus of probabilities, is, that our +solar system and the stars both change their places in space. According to +the admirable researches of d'Argelander at Abo, who has extended and more +perfectly developed the work begun by William Herschel and Prevost, the Sun +moves in the direction of the constellation Hercules, and probably, from the +combination of the observations made of 537 stars, toward a point lying (at +the equinox of 1792.5) at 257ºdegrees 49.'7 R.A., and 28ºdegrees 49.'7 +N.D. It is extremely difficult, in investigations of this nature, to +separate the absolute from the relative motion, and to determine what is +aloone owing to the solar system.* + + +[footnote] *Regarding the motion of the solar system, according to Bradley, +Tobias Mayer, Lambert, Lalande, and William Herschel, see Arago in the +'Annuaire', 1842, p. 388-399' Argelander, in Schum., 'Astron. Nachr +., No. 363, 364, 398, and in the treatise 'Von der eigenen Bewegung des +Sonnensystems' (On the proper Motion of the Solar System), 1837, s. 43, +respecting Perseus as the central body of the whole stellar stratum, +likewise Otho Struve, in the 'Bull. de l'Acad. de St. Pétersb.', 1842, t. +x., No. 9, p. 137-139. The last-named astronomer has found, by a mo4re +recent combination, 261ºdegrees 23' R.A.+37ºdegrees 36' Decl. for the +direction of the Sun's motion; and, taking the mean of his own results with +that of Argelander, we have, by a combination of 797 stars, the formula +259ºdegrees 9' R.A.+34ºdegrees 36' Decl. + + +If we consider the proper, and not the perspective motions of the stars, we +shall find many that appear to be distributed in groups, having an opposite +direction; and facts hitherto observed do not, at any rate, render it a +necessary assumption that all parts of our starry stratum, or the whole of +the stellar islands filling space, should move round one large unknown +luminous or non-luminous central body. The tendency of the human mind to +investigate ultimate and highest causes certainly inclines the intellectual +activity, no less than the imagination of mankind, to adopt such an +hypothesis. Even the Stagirite proclaimed that "every thing which is moved +must be referable to a motor, and that there would be no end to +p 147 +the concatenation of causes if there were not one primordial immovable +morot."* + + +[footnote] *Aristot., 'de Cælo', iii., 2, p. 301, Bekker: 'Phys.', viii., +t, p. 256. + + + +This material taken from pages 147-203 + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +The manifold translatory changes of the stars, not those produced by the +parallaxes at which they are seen from the changing position of the +spectator, but the true changes constantly going on in the regions of space, +afford us incontrovertible evidence of the 'dominion of the laws of +attraction' in the remotest regions of space, beyond the limits of our solar +system. The existence of these laws is revealed to us by many phenomena, +as, for instance, by the motion of double stars, and by the amount of +retarded or accelerated motion in different parts of their elliptic orbits. +Human inquiry need no longer pursue this subject in the domain of vague +conjecture, or amid the undefined analogies of the ideal world; for even +here the progress made in the method of astronomical observations and +calculations has enabled astronomy to take up its position on a firm basis. +It is not only the discovery of the astounding numbers of double and +multiple stars revolving round a center of gravity lying 'without' their +system (2800 such systems having been discovered up to 1837), but rather the +extension of our knowledge regarding the fundamental forces of the whole +material world, and the proofs we have obtained of the universal empire of +the laws of attraction, that must be ranked among the most brilliant +discoveries of the age. The periods of revolution of colored stars present +the greatest differences; thus, in some instances, the period extends to 43 +years, as in πpi of Corona, and in others to several thousands,, as in 66 +of Cetus, 38 of Gemini, and 100 of Pisces. Since Herschel's measurements in +1782, the satellite of the nearest star in the triple system of [Greek +letter] of Cancer has completed more than one entire revolution. By a +skillful combination of the altered distances and angles of position,* the +elements of these orbits may be found, conclusions drawn regarding the +absolute distance of the double stars from the Earth, and comparisons made +between their mass and that of the Sun. + + +[footnote] *Savary, in the 'Connaissance des Tems', 1830, p. 56 and 163. +Encke, 'Berl. Jahrb.', 1832, s. 253, etc. Arago, in the 'Annuaire' 1834, p. +260, 295. John Herschel, in the 'Memoirs of the Astronom. Soc.', vol. v., +p. 171. + + +Whether, however, here and in our solar system, quantity of matter is the +only standard of the amount of attractive force, or whether 'specific' +forces of attraction proportionate to the mass may not at the same time come +into operation, as Bessel was the first to conjecture, are questions +p 148 +whose practical solution must be left to future ages.* + + +[footnote] * Bessel, 'Untersuchung. des Theils der planetarischen +Storungen, welche aus der Bewegung der Sonne entstchen' (An Investigation of +the portion of the Planetary Disturbances depending on the motion of the +Sun) in 'Abh. der Berl. Akad. der Wissensch.', 1824 (Mathem. Classe), s. +2-6. The question has been raised by John Tobias Mayer, in 'Comment. Soc. +Reg. Gotting.', 1804-1808, vol. xvi., p. 31-68. + + +When we compare our Sun with the other fixed stars, that is, with other +self-luminous Suns in the lenticular starry stratum of which our system +forms a part, we find, at least in the case of some, that channels are +opened to us, which may lead, at all events, to an 'approximate' and limited +knowledge of their relative distances, volumes, and masses, and of the +velocities of their translatory motion. If we assume the distance of Uranus +from the Sun to be nineteen times that of the Earth, that is to say, +nineteen times as great as that of the Sun from the Earth, the central body +of our planetary system will be 11,900 times the distance of Uranus from the +star 'a' in the constellation Centaur, almost 31,300 from 61 Cygni, and +41,600 from Vega in the constellation Lyra. The comparison of the volume of +the Sun with that of the fixed stars of the first magnitude is dependent +upon the apparent diameter of the latter bodies -- an extremely undertain +optical element. If even we assume, with Herschel, that the apparent +diameter of Arcturus is only a tenth part of a second, it still follows that +the true diameter of this star is eleven times greater than that of the Sun.* + + +[footnote] *'Philos. Trans.' for 1803, p. 225. Arago, in the 'Annuaire', +1842, p. 375. In order to obtain a clearer idea of the distances ascribed +in a rather earlier part of the text to the fixed stars, let us assume that +the Earth is a distance of one foot from the Sun; Uranus is then 19 feet, +and Vega Lyrae is 158 geographical miles from it. + + +The distance of the star 61 Cygni, made known by Bessel, has led +approximately to a knowledge of the quantity of matter contained in this +body as a double star. Notwithstanding that, since Bradley's observations, +the portion of the apparent orbit traversed by this star is not sufficiently +great to admit of our arriving with perfect exactness at the true orbit nd +the major axis of this star, it has been conjectured with much probability +by the great Konigsberg astronomer,* "that the mass of this double star can +not be very considerably larger or smaller than half of the mass of the +Sun." + + +[footnote] *Bessel, in Schum., 'Jahrb.', 1839, s. 53. + + +This result is from actual measurement. The analogies deduced from the +relatively larger mass of those planets in our solar system that are +attended by satellites, and from the fact that Struve has discovered six +times more double stars among +p 194 +the brighter than among the telescopic fixed stars, have led other +astronomers to conjecture that the average mass of the larger number of the +binary stars exceeds the mass of the Sun.* + + +[footnote] *Mädler, 'Astron.', s. 476; also in Schum, 'Jahrb.', 1839, s. +95. + + +We are, however, far from having arrived at general results regarding this +subject. Our Sun, according to Argenlander, belongs, with reference to +proper motion in space, to the class of rapidly-moving fixed stars. + +The aspect of the starry heavens, the relative position of stars and +nebullae, the distribution of their luminous masses, the picturesque beauty, +if I may so express myself, of the whole firmament, depend in the course of +ages conjointly upon the proper motion of the stars and nebulae, the +translation of our solar system in space, the appearance of new stars, and +the disappearance or sudden diminution in the intensity of the light of +others, and lastly and specially, on the changes which the Earth's axis +experiences from the attraction of the Sun and Moon. The beautiful stars in +the constellation of the Centaur and the Southern Cross will at some future +time be visible in our northern latitudes, while other stars, as Sirius and +the stars in the Belt of Orion, will in their turn disappear below the +horizon. The places of the North Pole will successively be indicated by the +stars ß beta and a alpha Cephei, and ∂ delta Cygni, until after a period +of 12,000 years, Vega in Lyra will shine forth as the brightest of all +possible pole stars. These data give us some idea of the extent of the +motions which, divided into infinitely small portions of time, proceed +without intermission in the great chronometer of the universe. If for a +moment we could yield to the power of fancy, and imagine the acuteness of +our visual organs to be made equal with the extremest bounds of telescopic +vision, and bring together that which is now divided by long periods of +time, the apparent rest that reigns in space would suddenly disappear. We +should see the countless host of fixed stars moving in thronged groups in +different directions; nebulae wandering through space, and becoming +condensed and dissolved like cosmical clouds; the vail of the Milky Way +separated and broken up in many parts, and 'motion' ruling supreme in every +portion of the vault of heave, even as on the Earth's surface, where we see +it unfolded in the germ, the leaf, and the blossom, the organisms of the +vegetable world. The celebrated Spanish botanist Cavanilles was the first +who entertained the idea of "seeing grass grow," and he directed the +horizontal micrometer threads of a powerfully magnifying glass at one time to +p 150 +the apex of the shoot of a bambusa, and at another on the rapidly-growing +stem of an American aloe ('Agave Americana', precisely as the astronomer +places his cross of net-work against a culminating star. In the collective +life of physical nature, in the organic as in the sidereal world, all things +that have been, that are, and will be, are alike dependent on motion. + +The breaking up of the Milky Way, of which I have just spoken, requires +special notice. William Herschel, our safe and admirable guide to this +portion of the regions of space, has discovered by his star-guagings that +the telescopic breadth of the Milky Way extends from six to seven degrees +beyond what is indicated by our astronomical maps and by the extent of the +sidereal radiance visible to the naked eye.* + + +[footnote] *Sir William Herschel, in the 'Philos. Transact.' for 1817, Part +ii p. 438. + + +The two brilliant nodes in which the branches of the zone unite, in the +region of Cepheus and Cassiopeia, and in the vicinity of Scorpio and +Sagittarius, appear to exercise a powerful attraction on the contiguous +stars; in the most brilliant part, however between beta and [Greek symbol] +Cygni, one half of the 330,000 stars that have been discovered in a breadth +of 5 degrees are directed toward one side, and the remainder to the other. +It is in this part that Herschel supposes the layer to be broken up.* + + +[footnote] *Arago, in the 'Annuaire', 1842, p. 569 + + +The number of telescopic stars in the Milky Way uninterrupted by any nebulae +is estimated at 18 millions. In order, I will not say, to realize the +greatness of this number, but, at any rate, to compare it with something +analogous, I will call attention to the fact that there are not in the whole +heavens more than about 8000 stars between the first and the sixth +magnitudes, visible to the naked eye. The barren astonishment excited by +numbers and dimensions in space, when not considered with reference to +applications engaging the mental and perceptive powers of man, is awakened +in both extremes of the universe, in the celestial bodies as in the minutest +animalcules.* + + +[footnote] *Sir John Herschel, in a letter from Feldhuysen, dated Jan. +13th, 1836. Nicholl, 'Architecture of the Heavens', 1838, p. 22. (See, +also, some separate notices by Sir William Herschel on the starless space +which separates us by a great distance from the Milky Way, in the 'Philos. +Transact.' for 1817, Part ii., p. 328.) + + +A cubic inch of the polishing slate of Bilin contains, according to +Ehrenberg, 40,000 millions of the silicious shells of Galionellae. + +The stellar Milky Way, in the region of which, according to Argelander's +admirable observations, the brightest stars of the firmament appear to be +congregated, is almost at right angles +p 151 +with another Milky Way, composed of nebulae. The former constitutes, +according to Sir John Herschel's views, an annulus, that is to say, an +independent zone, somewhat remote from our lenticular-shaped starry stratum, +and similar to Saturn's ring. Our planetary system lies in an eccentric +direction, nearer to the region of the Cross than to the diametrically +opposite point, Cassiopeia.* + + +[footnote] *Sir John Herschel, 'Astronom.', 624; likewise in his +'Observations on Nebulae and Clusters of Stars' ('Phil. Transact.', 1833, +Part ii., p. 479, fig. 25): "We have here a brother system, bearing a real +physical resemblance and strong analogy of structure to our own." + + +An imperfectly seen nebulous spot, discovered by Messier in 1774, appeared +to present a remarkable similarity to the form of our starry stratum and the +divided ring of our Milky Way.* + + +[footnote] *Sir William Herschel, in the 'Phil. Trans.' for 1785, Part i., +p. 257. Sir John Herschel, 'Astron.', 616. ("The 'nebulous' region of the +heavens forms 'a nebulous Milky Way', composed of distinct nebulae, as the +other of stars." The same observation was made in a letter he addressed to +me in March, 1829.) + + +The Milky Way composed of nebulae does not belong to our starry stratum, but +surrounds it at a great distance without being physically connected with it, +passing almost in the form of a large cross through the dense nebulae of +Virgo, especially in the northern wing, through Comae Berenicis, Ursa Major, +Andromeda's girdle, and Pisces Boreales. It probably intersects the stellar +Milky Way in Cassiopeia, and connects its dreary poles (rendered starless +from the attractive forces by which stellar bodies are made to agglomerate +into groups) in the least dense portion of the starry stratum. + +We see from these considerations that our starry cluster, which bears traces +in its projecting branches of having been subject in the course of time to +various metamorphoses, and evinces a tendency to dissolve and separate, +owing to secondary centers of attraction -- is surrounded by two rings, one +of which, the nebulous zone, is very remote, while the other is nearer, and +composed of stars alone. The latter, which we generally term the Milky Way, +is composed of nebulous stars, averaging from the tenth to the eleventh +degree of magnitude,* but appearing, when considered individually, of very +different magnitudes, while isolated starry clusters (starry swarms) almost +always exhibit throughout a character of great uniformity in magnitude and +brilliancy. + + +[footnote] *Sir John Herschel, 'Astron.', 585. + + +In whatever part the vault of heaven has been pierced by powerful and +far-penetrating telescopic instruments, stars or luminous nebulae are every +where discoverable, the former, in +p 152 +some cases, not exceeding the twentieth or twenty-fourth degree of +telescopic magnitude. A portion of the nebulous vapor would probably be +found resolvable into stars by more powerful optical instruments. As the +retina retains a less vivid impression of separate than of infinitely near +luminous points, less strongly marked photometric relations are excited in +the latter case, as Arago has recently shown.* + + +[footnote] *Arago, in the 'Annuaire', 1842, p. 282-285, 409-411, and +439-442. + + +The definite or amorphous cosmical vapor so universally diffused, and which +generates heat through condensation, probably modifies the transparency of +the universal atmosphere, and diminishes that uniform intensity of light +which, according to Halley and Olbers, should arise, if every point +throughout the depths of space were filled by an infinite series of stars.* + + +[footnote] *Olbers, on the transparency of celestial space, in Bode's +'Jahrb.', 1826, s. 110-121. + + +The assumption of such a distribution in space is, however, at variance with +observation, which shows us large starless regions of space, 'openings' in +the heavens, as William Herschel terms them -- one, four degrees in width, +in Scorpio, and another in Serpentarius. In the vicinity of both, near +their margin, we find unresolvable nebulae, of which that on the western +edge of the opening Scorpio is one of the most richly thronged of the +clusters of small stars by which the firmament is adorned. Herschel +ascribes these openings or starless regions to the attractive and +agglomerative forcesof the marginal groups.* + + +[footnote] *"An opening in the heavens," William Herschel, in the 'Phil. +Trans.' for 1785, vol. lxxv., Part i., p. 256. Le Francais Lalande, in the +'Connaiss. des Tems pour l'An.' VIII., p. 383. Arago, in the 'Annuaire', +1842, p. 425. + + +"They are parts of our starry stratum," says he, with his usual graceful +animation of style, "that have experienced great devastation from time." If +we picture to ourselves the telescopic stars lying behind one another as a +starry canopy spread over the vault of heaven, these starless regions in +Scorpio and Serpentarius may, I think, be regarded as tubes through which we +may look into the remotest depths of space. Other stars may certainly lie +in those parts where the strata forming the canopy are interrupted, but +these are unattainable by our instruments. The aspect of fiery meteors had +led the ancients likewise to the idea of clefts or openings ('chasmata') in +the vault of heaven. These openings were, however, only regarded as +transient, while the reason of their being luminous and fiery, instead of +obscure, was supposed to be owing to the +p 153 +translucent illuminated ether which lay beyond them.* + + +[footnote] *Aristot., 'Meteor.', ii.,, 5, 1. Seneca, 'Natur. Quaest.', i., +14, 2. "Coelum discessisse," in Cic., 'de Divin.', i., 43. + + +Derham, and even Huygens, did not appear disinclined to explain in a similar +manner the mild radiance of the nebulae.* + + +[footnote] *Arago, in the 'Annuaire', 1842, p. 429. + + +When we compare the stars of the first magnitude, which, on an average, are +certainly the nearest to us, with the non-nebulous telescopic stars, and +further, when we compare the nebulous stars with unresolvable nebulae, for +instance, with the nebula in Andromeda, or even with the so-called planetary +nebulous vapor, a fact is made manifest to us by the consideration of the +varying distances and the boundlessness of space, which shows the world of +phenomena, and that which constitutes its causal reality, to be dependent +upon the 'propagation of light'. The velocity of this propagation is +according to Struve's most recent investigations, 166,072 geographical miles +in a second, consequently almost a million of times greater than the +velocity of sound. According to the measurements of Maclear, Bessel, and +Struve, of the parallaxes and distances of three fixed stars of very unequal +magnitudes ('a' Centauri, 16 Cygni, and 'a' Lyrae), a ray of light requires +respectively 3, 9 1/4, and 12 years to reach us from these three bodies. In +the short but memorable period between 1572 and 1604, from the time of +Cornelius Gemma and Tycho Brahe to that of Kepler, three new stars suddenly +appeared in Cassiopeia and Cygnus, and in the foot of Serpentarius. A +similar phenomenon exhibited itself at intervals in 1670, in the +constellation Vulpis. In recent times, even since 1837, Sir John Herschel +has observed, at the Cape of Good Hope, the brilliant star [Greek symbol] in +Argo increase in splendor from the second to the first magnitude.* + + +[footnote] *In December, 1837, Sir John Herschel saw the star [Greek +symbol] Argo, which till that time appeared as of the second magnitude, and +liable to no change, rapidly increase till it became of the first magnitude. + In January, 1838, the intensity of its light was equal to that of 'a' +Centauri. According to our latest information, Maclear in March, 1843, +found it as bright as Canopus; and even 'a' Crucis looked faint by [Greek +symbol] Argo. + + +These events in the universe belong, however, with reference to their +historical reality, to other periods of time than those in which the +phenomena of light are first revealed to the inhabitants of the Earth: they +reach us like the voices of the past. It has been truly said, that with our +large and powerful telescopic instruments we penetrate alike through the +boundaries of time and space: we measure the former through the latter, for +in the course of an +p 154 +hour a ray of light traverses over a space of 592 millions of miles. While +according to the theogony of Hesiod, the dimensions of the universe were +supposed to be expressed by the time occupied by bodies in falling to the +ground ("the brazen anvil was not more than nine days and nine nights in +falling from heaven to earth"), the elder Herschel was of opinion* that +light required almost two millions of years to pass to the Earth from the +remotest luminous vapor reached by his forty-foot reflector. + + +[footnote] *"Hence it follows that the rays of light of the remotest +nebulae must have been almost two millions of years on their way, and that +consequently, so many years ago, this object must already have had an +existence in the sidereal heaven, in order to send out those rays by which +we now perceive it." William Herschel, in the 'Phil. Trans.' for 1802, p. +498. John Herschel, 'Astron.', 590. Arago, in the 'Annuaire', 1842, p. +334, 359, and 382-385. + + +Much, therefore, has vanished long before it is rendered visible to us -- +much that we see was once differently arranged from what it now appears. +The aspect of the starry heavens presents us with the spectacle of that +which is only apparently simultaneous, and however much we may endeavor, by +the aid of optical instruments, to bring the mildly-radiant vapor of +nebulous masses or the faintly-glimmering starry clusters nearer, and +diminish the thousands of years interposed between us and them, that serve +as a criterion of their distance, it still remains more than probable, from +the knowledge we possess of the velocity of the transmission of luminous +rays, that the light of remote heavenly bodies presents us with the most +ancient perceptible evidence of the existence of matter. It is thus that +the reflective mind of man is led from simple premises to rise to those +exalted heights of nature, where in the light-illumined realms of space, +"myriads of worlds are bursting into life like the grass of the night."* + + +[fotnote] *From my brother's beautiful sonnet "Freiheit und Gesetz." +(Wilhelm von Humboldt, 'Gesammelte Werke', bd. iv., s. 358, No. 25.) + + +From the regions of celestial forms, the domain of Uranus, we will now +descend to the more contracted sphere of terrestrial forces -- to the +interior of the Earth itself. A mysterious chain links together both +classes of phenomena. According to the ancient signification of the Titanic +myth,* the powers of organic life, that is to say, the great order of +nature, depend upon the combined action of heaven and earth. + + +[footnote] *Otfried Muller, 'Prolegomena', s. 373. + + +If we suppose that the Earth, like all the other planets, primordially +belonged, according to its origin, to the central body, the Sun, and to the +solar atmosphere that has been separated into nebulous +p 155 +rings, the same connection with this continguous Sun, as well as with all +the remote suns that shine in the firmament, is still revealed through the +phenomena of light and radiating heat. The difference in the degree of +these actions must not lead the physicist, in his delineation of nature, to +forget the connection and the common empire of similar forces in the +universe. A small fraction of telluric heat is derived from the regions of +universal space in which our planetary system is moving, whose temperature +(which according to Fourier, is almost equal to our mean icy polar heat) is +the result of the combined radiation of all the stars. The causes that more +powerfully excite the light of the Sun in the atmosphere and in the upper +strata of our air, that give rise to heat-engendering electric and magnetic +currents, and awaken and genially vivify the vital spark in organic +structures on the earth's surface, must be reserved for the subject of our +future consideration. + +As we purpose for the present to confine ourselves exclusively within the +telluric sphere of nature, it will be expedient to cast a preliminary glance +over the relations in space of solids and fluids, the form of the Earth, its +mean density, and the partial distribution of this density in the interior +of our planet, its temperature and its electro-magnetic tension. From the +consideration of these relations in space, and of the forces inherent in +matter, we shall pass to the reaction of the interior on the exterior of our +globe; and to the special consideration of a universally distributed natural +power -- subterranean heat; to the phenomena of earthquakes, exhibited in +unequally expanded circles of commotion, which are not referable to the +action of dynamic laws alone; to the springing forth of hot wells; and, +lastly, to the more powerful actions of volcanic processes. The crust of +the Earth, which may scarcely have been perceptibly elevated by the sudden +and repeated, or almost uninterrupted shocks by which it has been moved from +below, undergoes, nevertheless, great changes in the course of centuries in +the relations of the elevation of solid portions, when compared with the +surface of the liquid parts, and even in the form of the bottom of the sea. +In this manner simultaneous temporary or permanent fissures are opened, by +which the interior of the Earth is brought in contact with the external +atmosphere. Molten masses, rising from an unknown depth, flow in narrow +streams along the declivity of mountains, rushing impetuously onward, or +moving slowly and gently, until the fiery source is quenched in the midst of +exhalations, and the lava becomes incrusted, as it were, by +p 156 +the solidification of its outer surface. New masses of rocks are thus +formed before our eyes, while the older ones are in their turn converted +into other forms by the greater or lesser agency of Platonic forces. Even +where no disruption takes place the crystalline moleculres are displaced, +combining to form bodies of denser texture. The water presents structures +of a totally different nature, as, for instance, concretions of animal and +vegetable remains, of earthy, calcareous, or aluminous precipitates, +agglomerations of finely-pulverized mineral bodies, covered with layers of +the silicious shields of infusoria, and with transported soils containing +the bones of fossil animal forms of a more ancient world. The study of the +strata which are so differently formed and arranged before our eyes, and of +all that has been so variously dislocated, conforted, and upheaved, by +mutual compression and volcanic force, leads the reflective observer, by +simple analogies, to draw a comparison between the present and an age that +has long passed. It is by a combination of actual phenomena, by an ideal +enlargement of relations in space, and of the amount of active forces, that +we are able to advance into the long sought and indefinitely anticipated +domain of geognosy, which has only within the last half century been based +on the solid foundation of scientific deduction. + +It has been acutely remarked, "that notwithstanding our continual employment +of large telescopes, we are less acquainted with the exterior than with the +interior of other planets, excepting, perhaps, our own satellite." They +have been weighed, and their volume measured; and their mass and density are +becoming known with constantly-increasing exactness; thanks to the progress +made in astronomical observation and calculation. Their physical character +is, however, hidden in obscurity, for it is only in our own globe that we +can be brought in immediate contact with all the elements of organic and +inorganic creation. The diversity of the most heterogenous substances, +their admixtures and metamorphoses, and the ever-changing play of the forces +called into action, afford to the human mind both nourishment and enjoyment, +and open an immeasurable field of observation, from which the intellectual +activity of man derives a great portion of its grandeur and power. The +world of perceptive phenomena is reflected in the depths of the ideal world, +and the richness of nature and the mass of all that admits of classification +gradually become the objects of inductive reasoning. + +I would here allude to the advantage, of which I have already +p 157 +spoken, possessed by that portion of physical science whose origin is +familiar to us, and is connected with our earthly existence. The physical +description of celestial bodies from the remotely-glimmering nebulae with +their suns, to the central body of our own system, is limited, as we have +seen, to general conceptions of the volume and quantity of matter. No +manifestation of vital activity is there presented to our senses. It is +only from analogies, frequently from purely ideal combinations, that we +hazard conjectures on the specific elements of matter, or on their various +modifications in the different planetary bodies. But the physical knowledge +of the heterogeneous nature of matter, its chemical differences, the regular +forms in which its molecules combine together, whether in crystals or +granules; its relations to the deflected or decomposed waves of light by +which it is penetrated; to radiating, transmitted, or polarized heat; and to +the brilliant or invisible, but not, on that account, less active phenomena +of electro-magnetism -- all this inexhaustible treasure, by which the +enjoyment of the contemplation of nature is so much heightened, is dependent +on the surface of the planet which we inhabit, and more on its solid than on +its liquid parts. I have already remarked how greatly the study of natural +objects and forces, and the infinite diversity of the sources they open for +our consideration, strengthen the mental activity, and call into action +every manifestation of intellectual progress. These relations require, +however, as little comment as that concatenation of causes by which +particular nations are permitted to enjoy a superiority over others in the +exercise of a material power derived from their command of a portion of +these elementary forces of nature. + +If, on the one hand, it were necessary to indicate the difference existing +between the nature of our knowledge of the Earth and of that of the +celestial regions and their contents, I am no less desirous, on the other +hand, to draw attention to the limited boundaries of that portion of +spacefrom which we derive all our knowledge of the heterogeneous character +of matter. This has been somewhat inappropriately termed the Earth's crust; +it includes the strata most contiguous to the upper surface of our planet, +and which have been laid open before us by deep fissure-like valleys, or by +the labors of man, in the bores and shafts formed by miners. These labors* +do not extend beyond a vertical depth of somewhat more than 2000 feet (about +one third of a geographical mile) below the +p 159 +level of the sea, and consequently only about 1/9800th of the Earth's +radius. + + +[footnote] *In speaking of the greatest depths within the Earth reached by +human labor, we must recollect that there is a difference between the +'absolute depth' (that is to say, the depth below the Earth's surface at +that point) and the 'relative depth' (or that beneath the level of the sea). + The greatest relative depth that man has hitherto reached is probably the +bore at the new salt-works at Minden, in Prussia: in June, 1814, it was +exactly 1993 feet, the absolute depth being 2231 feet. The temperature of +the water at the bottom was 98 degrees F., which assuming the mean +temperature of the air at 49.3 degrees gives an augmentation of temperature +of 1 degree for every 54 feet. The absolute depth of the Artesian well of +Grenelle, near Paris, is only 1795 feet. According to the account of the +missionary Imbert, the fire-springs, "Ho-tsing." of the Chinese, which are +sunk to obtain [carbureted] hydrogen gas for salt-boiling, far exceed our +Artesian springs in depth. In the Chinese province of Szu-tschuan these +fire-springs are very commonly of the depth of more than 2000 feet; indeed, +at Tseu-lieu-tsing (the place of continual flow) there is a Ho-tsing which, +in the year 1812, was found to be 3197 feet deep. (Humboldt, 'Asie +Centrale', t. ii., p. 521 and 525. 'Annales de l'Association de la +Propagation de la Foi', 1829, No. 16, p. 369.) + +[footnote continues] The relative depth reached at Mount Massi, in Tuscany, +south of Volterra, amounts, according to Matteuci, to only 1253 feet. The +boring at the new salt-works near Minden is probably of about the same +relative depth as the coal-mine at Apendale, near Newcastle-under-Lyme, in +Staffordshire, where men work 725 yards below the surface of the earth. +(Thomas Smith, 'Miner's Guide', 1836, p. 160.) Unfortunately, I do not know +the exact height of its mouth above the level of the sea. The relative +depth of the Monk-wearmouth mine, near Newcastle, is only 1496 feet. +(Phillips, in the 'Philos. Mag.', vol. v., 1834, p. 446.) That of the Liege +coal-mine, 'l'Esperance' at Seraing, is, according to M. Gernaert, Ingenieur +des Mines, 1223 feet in depth. The works of greatest absolute depth that +have ever been formed are for the most part situated in such elevated plains +or valleys that they either do not descend so low as the level of the sea, +or at most reach very little below it. Thus the Eselchacht, at Kuttenberg, +in Bohemia, a mine which can not now be worked, had the enormous absolute +depth of 3778 feet. (Fr. A. Schmidt, 'Berggestze der oter Mon.', abth. i., +bd. i., s. xxxii.) Also, at St. Daniel and at Geish, on the Rorerbubel, in +the 'Landgericht' (or provincial district) of Kitzbuhl, there were, in the +sixteenth century, excavations of 3107 feet. The plans of the works of the +Rorerbubel are still preserved. (See Joseph von Sperges, 'Tyroler +Bergwerksgeschichte', s. 121. Compare, also, Humboldt, 'Gutachten uber +√∫erantreibung des Meissner Stollens in die Freiberger Erzrevier', printed +in Herder, 'uber Herantreibung des Meissner Stollens in die Freiberger +Erzrevier', printed in Herder, 'uber den jetz begonnenen Erbstollen', 1838, +s. cxxiv.) We may presume that the knowledge of the extraordinary depth of +the Rorerbuhel reached England at an early period, for I find it remarked in +Gilbert, 'de Magnete', that men have penetrated 2400 or even 3000 feet into +the crust of the Earth. ("Exigua videtur terrae portio, quae unquam +hominibus spectanda emerget aut eruitur; cum profundinus in ejus viscera, +ultra efflorescentis extremitatis corruptelam, aut propter aquas in magnis +fodin, tanquam per venas scaturientesaut propter seris salubrioris ad vitam +operariorum sustinendam necessarii defectum, aut propter ingentex sumptus ad +tantos labores exantlandos, multasque difficultates, ad profundiores terrz' +partes penetrre non possumus; adeo ut quadrigentas aut [quod rarissime] +quingentas orgyas in quibusdam metallis descendisse, stupendus omnibus +videatur connatus." -- Guilielmi Gilberti, Colcestrensis, 'de Magnete +Physiologia nova'. Lond., 1600, p. 40.) + +[footnote continues] The absolute depth of the mines in the Saxon +Erzgebirge, near Freiburg, are: in the Thurmhofer mines, 1944 feet; in the +Honenbirker mines, 1827 feet; the relative depths are only 677 and 277 feet, +if, in order to calculate the elevation of the mine's mouth above the level +of the sea, we regard the elevation of Freiburg as determined by Reich's +recent observations to be 1269 feet. The absolute depth of the celebrated +mine of Joachimsthal, in Bohemia (Verkreuzung des Jung Hauer Zechen-und +Andreasganges), is full 2120 feet; so that, as Von Dechen's measurements +show that its surface is about 2388 feet above the level of the sea, it +follows that the excavations have not as yet reached that point. In the +Harz, the Samson mine at Andreasberg has an absolute depth of 2197 feet. In +what was formerly Spanish America, I know of no mine deeper than the +Valenciana, near Guanaxuato (Mexico), where I found the absolute depth of +the Planes de San Bernardo to be 1686 feet; but these planes are 5960 feet +above the level of the sea. If we compare the depth of the old Kuttenberger +mine (a depth greater than the height of our Brocken, and only 200 feet less +than that of Vesuvius) with the loftiest structures that the hands of man +have erected (with the Pyramid of Cheops and with the Cathedral of +Strasburg), we find that they stand in the ratio of eight to one. In this +note I have collected all the certain information I could find regarding the +greatest absolute and relative depths of mines and borings. In descending +eastward from Jerusalem toward the Dead Sea, a view presents itself to the +eye, which, according to our present hypsometrical knowledge of the surface +of our planet, is unrivaled in any country; as we approach the open ravine +through which the Jordan takes its course, we tread, with the open sky above +us, on rocks which, according to the barometric measurements of Berton and +Russegger are 1385 feet below the level of the Mediterranean. (Humboldt, +'Asie Centrale', th. ii., p. 323.) + + +The crystalline masses that have been erupted from active volcanoes, and are +generally similar to the rocks on the upper surface, have come from depths +which, although not accurately determined, must certainly be sixty times +greater than those to which human labor has been enabled to penetrate. We +are able to give in numbers the depth of the shaft where the strata of coal, +after penetrating a certain way, rise again at a distance that admits of +being accurately defined by measurements. These dips show that the +carboniferous strata, together with the fossil organic remains which they +contain, must lie, as, for instance, in Belgium, more than five or six +thousand feet* below the present level +p 160 +of the sea, and that the calcareous and the curved strata of the Devonian +basin penetrate twice that depth. + + +[footnote] *Basin-shaped curved strata, which dip and reappear at +measureable distances, although their deepest portions are beyond the reach +of the miner, afford sensible evidence of the nature of the earth's crust at +great depths below its surface. Testimony of this kind possesses, +consequently, a great geognostic interest. I am indebted to that excellent +geognosist, Von Dechen, for the following observations. "The depth of the +coal basin of Liege, at Mont St. Gilles, which I, in conjunction with our +friend Von Oeynhausen, have ascertained to be 3890 feet below the surface, +extends 3464 feet below the surface of the sea, for the absolute height of +Mont St. Gilles certainly does not much exceed 400 feet; the coal basin of +Mons is fully 1865 feet deeper. But all these depths are trifling compared +with those which are presented by the coal strata of Saar-Revier +(Saarbrucken). I have found after repeated examinations, that the lowest +coal stratum which is known in the neighborhood of Duttweiler, near +Bettingen, northeast of Saarlouis, must descend to depths of 20,682 and +22,015 feet (or 3.6 geographical miles) below the level of the sea." This +result exceeds, by more than 8000 feet, the assumption made in the text +regarding the basin of the Devonian strata. This coal-field is therefore +sunk as far below the surface of the sea as Chimborazo is elevated above it +-- at a depth at which the Earth's temperature must be as high as +435ºdegrees F. Hence, from the highest pinnacles of the Himalaya to the +lowest basins containing the vegetation of an earlier world, there is a +vertical distance of about 48,000 feet, or of the 435th part of the Earth's +radius. + + +If we compare these subterranean basins with the summits of montains that +have hitherto been considered as the most elevated portions of the raised +crust of the Earth, we obtain a distance of 37,000 feet (about seven miles), +that is, about the 1/524th of the Earth's radius. These, therefore, would +be the limits of vertical depth and of the superposition of mineral strata +to which geognostical inquiry could penetrate, even if the general elevation +of the upper surface of the earth were equal to the height of the +Dhawalagigi in the Himalaya, or of the Sorata in Bolivia. All that lies at +a greater depth below the level of the sea than the shafts or the basins of +which I have spoken, the limits to which man's labors have penetrated, or +than the depths to which the sea has in some few instances been sounded (Sir +James Ross was unable to find bottom with 27,600 feet of line), is as much +unknown to us as the interior of the other planets of our solar system. We +only know the mass of the whole Earth and its mean density by comparing it +with the open strata, which alone are accessible to us. In the interior of +the Earth, where all knowledge of its chemical and mineralogical character +fails, we are again limited to as pure conjecture, as in the remotest bodies +that revolve round the Sun. We can determine nothing with certainty +regarding the depth at which the geological strata must be supposed to be in +state of softening or of liquid fusion, of the cavities occupied by elastic +vapor, of the condition of fluids when heated under an enormous pressure, or +of the law of the increase +p 161 +of density from the upper surface to the center of the Earth. + +The consideration of the increase of heat with the increase of depth toward +the interior of our planet, and of the reaction of the interior on the +external crust, leads us to the long series of volcanic phenomena. These +elastic forces are manifested in earthquakes, eruptions of gas, hot wells, +mud volcanoes and lava currents from craters of eruption and even in +producing alterations in the level of the sea.* + + +[footnote] * [See Daubeney 'On Volcanoes', 2d edit., 3848, p. 539, etc., on +the so called 'mud volcanoes', and the reasons advanced in favor of adopting +the term "salses" to designate these phenomena.] -- Tr. + + +Large plains and variously indented continents are raised or sunk, lands are +separated from seas, and the ocean itself, which is permeated by hot and +cold currents, coagulates at both poles, converting water into dense masses +of rock, which are either stratified and fixed, or broken up into floating +banks. The boundaries of sea and land, of fluids and solids, are thus +variously and frequently changed. Plains have undergone oscillatory +movements, being alternately elevated and depressed. After the elevation of +continents, mountain chains were raised upon long fissures, mostly parallel, +and in that case, probably cotemporaneous; and salt lakes and inland seas, +long inhabited by the same creatures, were forcibly separated, the fossil +remains of shells and zoophytes still giving evidence of their original +connection. Thus, in following phenomena in their mutual dependence, we are +led from the consideration of the forces acting in the interior of the Earth +to those which cause eruptions on its surface, and by the pressure of +elastic vapors give rise to burning streams of lava that flow from open +fissures. + +The same powers that raised the chains of the Andes and the Hiimalaya to the +regions of perpetual snow, have occasioned new compositions and new textures +in the rocky masses, and have altered the strata which had been previously +deposited from fluids impregnated with organic substances. We here trace +the series of formations, divided and superposed according to their age, and +depending upon the changes of configuration of the surface, the dynamic +relations of upheaving forces, and the chemical action of vapors issuing +from the fissures. + +The form and distribution of continents, that is to say, of that solid +portion of the Earth's surface which is suited to the luxurious development +of vegetable life, are associated by intimate connection and reciprocal +action with the encircling +p 162 +sea in which organic life is almost entirely limited to the animal world. +The liquid element is again covered by the atmosphere, an aërial ocean in +which the mountain chains and high plains of the dry land rise like shoals, +occasioning a variety of currents and changes of temperature, collecting +vapor from the region of clouds, and distributing life and motion by the +action of the streams of water which flow from their declivities. + +While the geography of plants and animals depends on these intricate +relations of the distribution of sea and land, the configuration of the +surface, and the direction of isothermal lines (or zones of equal mean +annual heat), we find that the case is totally different when we consider +the human race -- the last and noblest subject in a physical description of +the globe. The characteristic differences in races, and their relative +numerical distribution over the Earth's surface, are conditions affected not +by natural relations alone, but at the same time and specially, by the +progress of civilization, and by moral and intellectual cultivation on which +depends the political superiority that distinguishes national progress. +Some few races, clinging, as it were, to the soil, are supplanted and ruined +by the dangerous vicinity of others more civilized than themselves, until +scarce a trace of their existence remains. Other races, again, not the +strongest in numbers, traverse the liquid element, and thus become the first +to acquire, although late, a geographical knowledge of at least the maritime +lands of the whole surface of our globe, from pole to pole. + +I have thus, before we enter on the individual characters of that portion of +the delineation of nature which includes the sphere of telluric phenomena, +shown generally in what manner the consideration of the form of the Earth +and the incessant action of electro-magnetism and subterranean heat may +enable us to embrace in one view the relations of horizontal expansion and +elevation on the Earth's surface, the geognostic type of formations, the +domain of the ocean (of the liquid portions of the Earth), the atmosphere +with its meteorological processes, the geographical distribution of plants +and animals, and, finally, the physical gradations of the human race, which +is, exclusively and every where, susceptible of intellectual culture. This +unity of contemplation presupposes a connection of phenomena according to +their internal combination. A mere tabular arrangement of these facts would +not fulfill the object I have proposed to myself, and would not satisfy that +requirement for cosmical presentation awakened in me by the +p 163 +aspect of nature in my journeyings by sea and land, by the careful study of +forms and forces, and by a vivid impression of the unity of nature in the +midst of the most varied portions of the Earth. In the rapid advance of all +branches of physical science, much that is deficient in this attempt will, +perhaps, at no remote period, be corrected and rendered more perfect, for it +belongs to the history of the development of knowledge that portions which +have long stood isolated become gradually connected, and subject to higher +laws. I only indicate the empirical path in which I and many others of +similar pursuits with myself are advancing, full of expectation that, as +Plato tells us Socrates once desired, "Nature may be interpreted by reason +alone."* + + +[footnote] *Plato, 'Phaedo', p. 97. (Arist., 'Metaph.', p. 985.) compare +Hegel, 'Philosophie der Geschichte', 1840, s. 16. + + +The delineation of the principal characteristics of telluric phenomena must +begin with the form of our planet and its relations in space. Here too, we +may say that it is not only the mineralogical character of rocks, whether +they are crystalline, granular, or densely fossiliferous, but the +geometrical form of the Earth itself, which indicates the mode of its +origin, and is, in fact, its history. An elliptical spheroid of revolution +gives evidence of having once been a soft or fluid mass. Thus the Earth's +compression constitutes one of the most ancient geognostic events, as every +attentive reader of the book of nature can easily discern; and an analogous +fact is presented in the case of the Moon, the perpetual direction of whose +axes toward the Earth, that is to say, the increased accumulation of matter +on that half of the Moon which is turned toward us, determines the relations +of the periods of rotation and revolution, and is probably contemporaneous +with the earliest epoch in the formative history of this satellite. The +mathematical figure of the Earth is that which it would have were its +surface covered entirely by water in a state of rest; and it is this assumed +form to which all geodesical measurements of degrees refer. This +mathematical surface is different from that true physical surface which is +affected by all the accidents and inequalities of the solid parts.* + + +[footnote] *Bessel, 'Allgemeine Betrachtungen uber Gradmessungen nach +astronomisch-geodätischen Arbeiten', at the conclusion of Bessel and +Baeyer, 'Gradmessung in Ostpreussen', s. 427. Regarding the accumulation of +matter on the side of the Moon turned toward us (a subject noticed in an +earlier part of the text), see Laplace, 'Expos. du Syst. du Monde', p. 308. + + +The whole figure of the Earth is determined when we know the amount of the +p 164 +compression at the poles and the equatorial diameter; in order, however, to +obtain a perfect representation of its form it is necessary to have +measurements in two directions, perpendicular to one another. + +Eleven measurements of degrees (or determinations of the curvature of the +Earth's surface in different parts), of which nine only belong to the +present century, have made us acquainted with the size of our globe, which +Pliny names "a point in the immeasurable universe."* + + +[footnote] *Plin., ii., 68. Seneca, 'Nat. Quaest., Praef., c. ii. "El +mundo espoco" (the Earth is small and narrow), writes Columbus from Jamaica +to Queen Isabella on the 7th of July, 1503: not because he entertained the +philosophic views of the aforesaid Romans, but because it appeared +advantageous to him to maintain that the journey from Spain was not long, +if, as he observes, "we seek the east from the west." Compare my 'Examen +Crit. de l'Hist. de la Geogr. du 15 me Siecle', t.i., p. 83, and t. ii., p. +327, where I have shown that the opinion maintained by Delisle, Freret, and +Gosselin, that the excessive differences in the statements regarding the +Earth's circumference, found in the writings of the Greeks, are only +apparent, and dependent on different values being attached to the stadia, +was put forward as early as 1495 by Jaime Ferrer, in a proposition regarding +the determination of the line of demarkation of the papal dominions. + + +If these measurements do not always accord in the curvatures of different +meridians under the same degree of latitude, this very circumstance speaks +in favor of the exactness of the instruments and the methods employed, and +of the accuracy and the fidelity to nature of these partial results. The +conclusion to be drawn from the increase of forces of attraction (in the +direction from the equator to the poles) with respect to the figure of a +planet is dependent on the distribution of density in its interior. Newton, +from theoretical principles, and perhaps likewise prompted by Cassini's +discovery, previously to 1666, of the compression of Jupiter,* determined, +in his immortal work, 'Philosophiae Naturalis Principia', that the +compression of the Earth, as a homogeneous mass, was 1/230th. + + +[footnote] *Brewster, 'Life of Sir Isaac Newton', 1831, p. 162. "The +discovery of the spheroidal form of Jupiter by Cassini had probably directed +the attention of Newton to the determination of its cause, and consequently, +to the investigation of the true figure of the Earth." Although Cassini did +not announce the amount of the compression of Jupiter (1/15th) till 1691 +('Anciens Memoires de l'Acad. des Sciences', t. ii., p. 108), yet we know +from Lalande ('Astron.', 3me ed., t. iii., p. 335) that Moraldi possessed +some printed sheets of a Latin work, "On the Spots of the Planets," +commenced by Cassini, from which it was obvious that he was aware of the +compression of Jupiter before the year 1666, and therefore at least +twenty-one years before the publication of Newton's 'Principia'. + + +Actual mesurements, +p 165 +made by the aid of new and more perfect analysis, have, however, shown that +the compression of the poles of the terrestrial spheroid, when the density +of the strata is regarded as increasing toward the center, is very nearly +1/300th. + +Three methods have been employed to investigate the curvature of the Earth's +surface, viz., measurements of degrees, oscillations of the pendulum, and +observations of the inequalities in the Moon's orbit. The first is a direct +geometrical and astronomical method, while in the other two we determine +from accurately observed movements the amount of the forces which occasion +those movements, and from these forces we arrive at the cause from whence +they have originated, viz., the compression of our terrestrial spheroid. In +this part of my delineation of nature, contrary to my usual practice, I have +instanced methods because their accuracy affords a striking illustration of +the intimate connection existing among the forms and forces of natural +phenomena, and also because their application has given occasion to +improvements in the exactness of instruments (as those employed in the +measurements of space) in optical and chronological observations; to greater +perfection in the fundamental branches of astronomy and mechanics in respect +to lunar motion and to the resistance experienced by the oscillations of the +pendulum; and to the discovery of new and hitherto untrodden paths of +analysis. With the exception of the investigations of the parallax of +stars, which led to the discovery of aberration and nutation, the history of +science presents no problem in which the object attained -- the knowledge of +the compression and of the irregular form of our planet -- is so far +exceeded in importance by the incidental gain which has accrued, through a +long and weary course of investigation, in the general furtherance and +improvement of the mathematical and astronomical sciences. The comparison +of eleven measurements of degrees (in which are included three +extra-European, namely, the old Peruvian and two East Indian) gives, +according to the most strictly theoretical requirements allowed for by +Bessel,* a compression +p 166 +of 1/299th. + + +[footnote] *According to Bessel's examination of ten measurements of +degrees, in which the error discovered by Poissant in the calculation of the +French measurements is taken into consideration (Schumacher, 'Astron. +Nachr.', 1841, No. 438, s. 116), the semi-axis major of the elliptical +spheroid of revolution to which the irregular figure of the Earth most +closely approximates is 3,272,077.14 toises, or 20,924,774 feet; the +semi-axis minor, 3,261,159,83 toises, or 20,854,821 feet; and the amount of +compression or eccentricity 1/299.152d; the length of a mean degree of the +meridian, 57,013.109 toises, or 364,596 feet, with an error of + 2.8403 +toises, or 18.16 feet, whence the length of a geographical mile is 3807.23 +toises, or 6086.7 feet. Previous combinations of measurements of degrees +varied between 1/302d and 1/297th; thus Walbeck ('De Forma of Magnitudine +telluris in demensis arcubus Meridiani definiendis', 1819) gives 1/30278th: +Ed. Schmidt ('Lehrbuch der Mathem. und Phys. Geographie', 1829, s. 5) gives +1/20742d, as the mean of seven measures. Respecting the influence of great +differences of longitude on the polar compression, see 'Bibliotheque +Universelle', t. xxxiii., p. 181, and t. xxxv., p. 50: likewise +'Connaissance des Tems', 1829, p. 290. From the lunar inequalities alone, +Laplace ('Exposition du Syst. du Monde', p. 229) found it, by the older +tables of Burg, to be 1/3245th; and subsequently, from the lunar +observations of Burckhardt and Bouvard, he fixed it at 1/299.1th ('Mecanique +Celeste', t. v., p. 13 and 43). + + +In accordance with this, the polar radius is 10,938 toises (69,944 feet), or +about 11 1/2 miles, shorter than the equatorial radius of our terrestrial +spheroid. The excess at the equator in consequence of the curvature of the +upper surface of the globe amounts, consequently, in the direction of +gravitation, to somewhat more than 4 3/7th times the height of Mont Blanc, +or only 2 1/2 times the probable height of the summit of the Chawalagiri, in +the Himalaya chain. The lunar inequalities (perturbation in the moon's +latitude and longitude) give according to the last investigations of +Laplace, almost the same result for the ellipticity as the measurements of +degrees, viz., 1/299th. The results yielded by the oscillation of the +pendulum give, on the whole, a much greater amount of compression, viz., +1/288th.* + + +[footnote] *The oscillations of the pendulum give 1/288.7th as the general +result of Sabine's great expedition (1822 and 1823, from the equator to 80 +degrees north latitude); according to Freycinet, 1/286.2d, exclusive of the +experiments instituted at the Isle of France, Guam, and Mowi (Mawi); +according to Forster, 1/289.5th; according to Duperrey, 1/266.4th; and +according to Lutke ('Partie Nautique', 1836, p. 232), 1/270th, calculated +from eleven stations. On the other hand, Mathieu ('Connais. des Temps', +1816, p. 330) fixed the amount at 1/298.2d, from observations made between +Formentera and Dunkirk; and Biot, at 1/304th, from observations between +Formentera and the island of Ust. Compare Baily, 'Report on Pendulum +Experiments', in the 'Memoirs of the Royal Astronomical Society', vol. vii., +p. 96; also Borenius, in the 'Bulletin de l'Acad. de St. Petersbourg', 1843, +t. i., p. 25. The first proposal to apply the length of the pendulum as a +standard of measure, and to establish the third part of the seconds pendulum +(then supposed to be every where of equal length) as a 'pes horarius', or +general measure, that might be recovered at any age and by all nations, is +to be found in Huygens's 'Horologium Oscillatorium', 1673, Prop. 25. A +similar wish was afterward publicly expressed, in 1742, on a monument +erected at the equator by Bouguer, La Condamine, and Godin. On the +beautiful marble tablet which exists, as yet uninjured, in the old Jesuits' +College at Quito, I have myself read the inscription, 'Penduli simplicis +aequinoctialis unius minuti secundi archetypus, mensurae naturalis exemplar, +utinam universalis!' From an observation made by La Condamine, in his +'Journal du Voyage a l'Equateur', 1751, p. 163, regarding parts of the +inscription that were not filled up, and a slight difference between Bonguer +and himself respecting the numbers, I was led to expect that I should find +considerable discrepancies between the marble tablet and the inscription as +it had been described in Paris; but, after a careful comparison, I merely +found two "ex arca graduum plusquam trium," and the date of 1745 instead of +1742. The latter circumstance is singular, because La Condamine returned to +Europe in November, 1744, Bouguer in June of the same year, and Godin had +left South America in July, 1744. The most necessary and useful amendment +to the numbers on this inscription would have been the astronomical +longitude of Quito. (Humboldt, 'Recueil d'Observ. Astron.', t. ii., p. +319-354.) Nouet's latitudes, engraved on Egyptian monuments, offer a more +recent example of the danger presented by the grave perpetuation of false or +careless results. + + +Galileo, who first observed when a boy (having, probably, suffered his +thoughts to wander from the service) that the height of the vaulted roof of +a church might be measured by the time of the vibration of the chandeliers +suspended at different altitudes, could hardly have anticipated that the +pendulum would one day be carried from pole to pole, in order to determine +the form of the Earth, or, rather, that the unequal density of the strata of +the Earth affects the length of the seconds pendulum by means of intricate +forces of local attraction, which are, however, almost regular in large +tracts of land. These geognostic relations of an instrument intended for +the measurement of time -- this property of the pendulum, by which, like a +sounding line, it searches unknown depths, and reveals in volcanic islands,* +or in the declivity of elevated continental mountain chains,** dense masses +of basalt and melaphyre instead of cavities, render it difficult, +notwithstanding the admirable simplicity of the method, to arrive at any +great result regarding the figure of the Earth from observation of the +oscillations of the pendulum. + + +[footnote] *Respecting the augmented intensity of the attraction of +gravitation in volcanic islands (St. Helena, Ualan, Fernando de Noronha, +Isle of France, Guam, Mowe, and Galapagos), Rawak (Lutke, p. 240) being an +exception, probably in consequence of its proximity to the highland of New +Guinea, see Mathieu, in Delambre, 'Hist. de l'Astronomie, au 18me Siecle', +p. 701. + + +[footnote] **Numerous observations also show great irregularities in the +length of the pendulum in the midst of continents, and which are ascribed to +local attractions. (Delambre, 'Mesure de la Meridienne', t. iii., p. 548; +Biot, in the 'Mem. de l'Academie des Sciences', t. viii., 1829, p. 18 and +23.) In passing over the South of France and Lombardy from west to east, we +find the minimum intensity of gravitation at Bordeaux; from thence it +increases rapidly as we advance eastward, through Figeac, Clermont-Ferrand, +Milan, and Padua; and in the last town we find that the intensity has +attained its maximum. The influence of the southern declivities of the Alps +is not merely t on the general size of their mass, but (much more), in the +opinion of Elie de Beaumont ('Rech. sur les Revol. de la Surface du Globe', +1830, p. 729), on the rocks of melaphyre and serpentine, which have elevated +the chain. On the declivity of Ararat, which with Caucasus may be said to +lie in the center of gravity of the old continent formed by Europe, Asia, +and Africa, the very exact pendulum experiments of Fedorow give indications, +not of subterranean cavities, but of dense volcanic masses. (Parrot, 'Reise +zum Ararat', bd. ii., s. 143.) In the geodesic operations of Carlini and +Plana, in Lombardy, differences ranging from 20" to 47".8 have been found +between direct observations of latitude and the results of these operations. + (See the instances of Andrate and Mondovi, and those of Milan and Padua, in +the 'Operations Geodes. et Astron. pour la Mesure d'un Arc du Parallele +Moyen', t. ii., p. 347; 'Effemeridi Astron. di Milano', 1842, p. 57.) The +latitude of Milan, deduced from that of Berne, according to the , is +45ºdegrees 27' 52", while, according to direct astronomical observations, +it is 45 degrees 27' 35". As the perturbations extend in the plain of +Lombardy to Parma, which is far south of the Po (Plana, 'Operat. Geod.', t. +ii., p. 847), it is probable that there are deflecting causes 'concealed +beneath the soil of the plain itself'. Struve has made similar experiments +[with corresponding results] in the most level parts of eastern Europe. +(Schumacher, 'Astron. Nachrichten', 1830, No. 164, s. 399.) Regarding the +influence of dense masses supposed to lie at a small depth, equal to the +mean height of the Alps, see the analytical expressions given by Hossard and +Rozet, in the 'Comptes Rendus', t. xviii., 1844, p. 292, and compare them +with Poisson, 'Traite de Mecanique' (2me ed., t. i., p. 482. The earliest +observations on the influence which different kinds of rocks exercise on the +vibration of the pendulum are those of Thomas Young, in the 'Philos. +Transactions' for 1819, p. 70-96. In drawing conclusions regarding the +Earth's curvature from the length of the pendulum, we ought not to overlook +the possibility that its crust may have undergone a process of hardening +previously to metallic and dense basaltic masses having penetrated from +great depths, through open clefts, and approached near the surface. + + +In the astronomical part of the determination of degrees of latitude, +mountain chains, or the denser strata of the Earth, likewise exercise, +although in a less degree, an unfavorable influence on the measurement. + +As the form of the Earth exerts a powerful influence on the motions of other +cosmical bodies, and especially on that of its own neighboring satellite, a +more perfect knowledge of the motion of the latter will enable us +reciprocally to draw an inference regarding the figure of the Earth. Thus, +as Laplace ably remarks,* "An astronomer, without leaving his observatory, +may, by a comparison of lunar theory with true observations, not only be +enabled to determine the form and size of the Earth, but also its distance +from the Sun and Moon -- results that otherwise could only be arrived at by +long and arduous expeditions to the most remote parts of both hemispheres." + + +[footnote] *Laplace, 'Expos. du Syst. du Monde', p. 231. + + +p 169 +The compression which may be inferred from lunar inequalities affords an +advantage not yielded by individual measurements of degrees or experiments +with the pendulum, since it gives a mean amount which is referable to the +whole planet. The comparison of the Earth's compression with the velocity +of rotation shows, further, the increase of density from the strata from the +surface toward the center -- an increase which a comparison of the ratios of +the axes of Jupiter and Saturn with their times of rotation likewise shows +to exist in these two large planets. Thus the knowledge of the external +form of planetary bodies leads us to draw conclusions regarding their +internal character. + +The northern and southern hemispheres appear to present nearly the same +curvature under equal degrees of latitude, but, as has already been +observed, pendulum experiments and measurements of degrees yield such +different results for individual portions of the Earth's surface that no +regular figure can be given which would reconcile all the results hitherto +obtained by this method. the true figure of the Earth is to a regular +figure as the uneven surfaces of water in motion are on the even surface of +water at rest. + +When the Earth had been measured, it still had to be weighed. The +oscillations of the pendulum* and the plummet have here likewise served to +determine the mean density of the Earth, either in connection with +astronomical and geodetic operations, with the view of finding the +deflection of the plummet from a vertical line in the vicinity of a +mountain, or by a comparison of the length of the pendulum in a plain and on +the summit of an elevation, or, finally, by the employment of a torsion +balance, which may be considered as a horizontally vibrating pendulum for +the measurement of the relative density of neighbouring strata. + + +[footnote] *La Caille's pendulum measurements at the Cape of Good Hope, +which have been calculated with much care by Mathieu (Delambre, 'Hist. de +l'Astron. au 18me Siecle', p. 479), give a compression of 1/284.4th; but, +from several comparisons of observations made in equal latitudes in the two +hemispheres (New Holland and the Malouines (Falkland Islands), compared with +Barcelona, New York, and Dunkirk), there is as yet no reason for supposing +that the mean compression of the southern hemisphere is greater than that of +the northern. (Biot, in the 'Mem. de l'Acad. des Sciences', t. viii., 1829, +p. 39-41.) + + +Of these three methods* the +p 170 +last is the most certain, since it is independent of the difficult +determination of the density of the mineral masses of which the spherical +segment of the mountain consists near which the observations are made. + +[footnote] *The three methods of observation give the following results: +(1.) by the deflection of the plumb-line in the proximity of the Shehallien +Mountain (Gaelic, Thichallin) in Perthshire, r.713, as determined by +Maskelyne, Hutton, and Playfair (1774-1776 and 1810), according to a method +that had been proposed by Newton; (2.) by pendulum vibrations on mountains, +4.837 (Carlini's observations on Mount Cenis compared with Biot's +observations at Bordeaux, 'Effemer. Astron. di Milano', 1824, p. 184); (3.) +by the torsion balance used by Cavendish, with an apparatus originally +devised by Mitchell, 5.48 (according to Hutton's revision of the +calculation, 5.32, and according to that of Eduard Schmidt, 5.52; 'Lehrbuch +der Math. Geographie', bd. i., s. 487); by the torsion balance, according to +Reich, 5.44. In the calculation of these experiments of Professor Reich, +which have been made with masterly accuracy, the original mean result was +5.43 (with a probable error of only 0.0233), a result which, being increased +by the quantity by which the Earth's centrifugal force diminishes the force +of gravity for the latitude of Freiberg (50 degrees 55'), becomes changed to +5.44. The employment of cast iron instead of lead has not presented any +sensible difference, or none exceeding the limits of errors of observation, +hence disclosing no traces of magnetic influences. (Reich, 'Vrsuche uber +die mittlere Dichtigheit der Erde', 1838, s. 60, 62, and 66.) By the +assumption of too slight a degree of ellipticity of the Earth, and by the +uncertainty of the estimations regarding the density of rocks on its +surface, the mean density of the Earth, as deduced from experiments on and +near mountains, was found about one sixth smaller than it really is, namely, +4.761 (Laplace, 'Mecan. Celeste', t. v., p. 46), or 4.785. (Eduard Schmidt, +'Lehrb. der Math. Geogr.', bd. i., 387 und 418.) On Halley's hypothesis of +the Earth being a hollow sphere (noticed in page 171), which was the germ of +Franklin's ideas concerning earthquakes, see 'Philos. Trans.' for the year +1693, vol. xvii., p. 563 ('On the Structure of the Internal Parts of the +Earth, and the concave habited 'Arch of the Shell'). Halley regarded it as +more worthy of the Creator "that the Earth, like a house of several stories, +should be inhabited both without and within. For light in the hollow sphere +(p. 576) provision might in some manner be contrived." + + +According to the most recent experiments of Reich, the result obtained is +5.44; that is to say, the mean density of the whole Earth is 5.44 times +greater than tht of pure water. As according to the nature of the +mineralogical strata constituting the dry continental part of the Earth's +surface, the mean density of this portion scarcely amounts to 2.7, and the +density of the dry and liquid surface conjointly to scarcely 1.6, it follows +that the elliptical unequally compressed layers of the interior must greatly +increase in density toward the center, either through pressure or owing to +the heterogeneous nature of the substances. Here again we see that the +vertical, as well as the horizontally vibrating pendulum, may justly be +termed a geognostical instrument. + +The results obtained by the employment of an instrument of this kind have +led celebrated physicists, according to the difference of the hypothesis +from which they started, to adopt +p 171 +entirely opposite views regarding the nature of the interior of the globe. +It has been computed at what depths liquid or even gaseous substances would, +from the pressure of their own superimposed strata, attain a density +exceeding that of platinum or even iridium; and in order that the +compression which has been detrmined within such narrow limits might be +brought into harmony with the assumption of simple and infinitely +compressible matter, Leslie has ingeniously conceived the nucleus of the +world to be a hollow sphere, filled with an assumed "imponderable matter, +having an enormous force of expansion." These venturesome and arbitrary +conjectures have given rise, in wholly unscientific circles, to still more +fantastic notions. The hollow sphere has by degrees been peopled with +plants and animals, and two small subterranean revolving planets -- Pluto +and Proserpine -- were imaginatively supposed to shed over it their mild +light; as, however, it was further imagined that an ever-uniform temperature +reigned in these internal regions, the air, which was made self-luminous by +compression, might well render the planets of this lower world unnecessary. +Near the north pole, at 80 degrees latitude, whence the polar light +emanates, was an enormous opening, through which a descent might be made +into the hollow sphere, and Sir Humphrey Davy and myself were even publicly +and frequently invited by Captain Symmes to enter upon this subterranean +expedition: so powerful is the morbid inclination of men to fill unknown +spaces with shapes of wonder, totally unmindful of the counter evidence +furnished by well-attested facts and universally acknowledged natural laws. +Even the celebrated Halley, at the end of the seventeenth century, hollowed +out the Earth in his magnetic speculations. Men were invited to believe +that a subterranean freely-rotating nucleus occasions by its position the +diurnal and annual changes of magnetic declination. It has thus been +attempted in our own day, with tedious solemnity, to clothe in a scientific +garb the quaintly-devised fiction of the humorous Holbert.* + + +[footnote] *[The work referred to, one of the wittiest productions of the +learned Norwegian satirist and dramatist Holberg, was written in Latin, and +first appeared under the following title: 'Nicolai Klimii iter subterraneum +novam telluris theoriam ac historiam quintae monarchi Nicolai Klimii iter +subterraneum novam telluris theoriam ac historiam quintae monarchi ad huc +nobis incognitae exhibens e bibliotheca b. Abelini. Hafniae et Lipsiae sunt. + Jac. Preuss', 1741. An admirable Danish translation of this learned but +severe satire on the institutions, morals, and manners of the inhabitants of +the upper Earth, appeared at Copenhagen in 1789, and was entitled 'Niels +Klim's underjordiske reise ocd Ludwig Holberg, oversal after den Latinske +original of Jens Baggesen'. Holberg, who studied for a time at Oxford, was +born at Bergen in 1685, and died in 1754 as Rector of the University of +Copenhagen.] -- Tr. + + +p 172 +The figure of the Earth and the amount of solidification (density) which it +has acquired are intimately connected with the forces by which it is +animated, in so far, at least, as they have been excited or awakened from +without, through its planetry position with reference to a luminous central +body. Compression, when considered as a consequence of centrifugal force +acting on a rotating mass, explains the earlier condition of fluidity of our +planet. During the solidification of this fluid, which is commonly +conjectured to have been gaseous and primordially heated to a very high +temperature, an enormous quantity of latent heat must have been liberated. +If the process of solidification began as Fourier conjectures, by radiation +from the cooling surface exposed to the atmosphere, the particles near the +center would have continued fluid and hot. As, after long emanation of heat +from the center toward the exterior, a stable condition of the temperature +of the Earth would at length be established, it has been assumed that with +increasing depth the subterranean heat likewise uninterruptedly increases. +The heat of the water which flows from deep borings (Artesian wells), direct +experiments regarding the temperature of rocks in mines, but, above all, the +volcanic activity of the Earth, shown by the flow of molten masses from open +fissures, afford unquestionable evidence of this increase for very +considerable depths from the upper strata. According to conclusions based +certainly upon mere analogies, this increase is probably much greater toward +the center. + +That which has been learned by an ingenious analytic calculation, expressly +perfected for this class of investigations,* +p 173 +regarding the motion of heat in homogeneous metallic spheroids, must be +applied with much caution to the actual character of our planet, considering +our present imperfect knowledge of the substances of which the Earth is +composed, the difference in the capacity of heat and in the conducting power +of different superimposed masses, and the chemical changes experienced by +solid and liquid masses from any enormous compression. + + +[footnote] *Here we must notice the admirable analytical labors of Fourier, +Biot, Laplace, Poisson, Duhamel, and Lame. In his 'Theorie Mathematique de +la Chaleur', 1835, p. 3, 428-430, 436, and 521-524 (see, also, De la Rive's +abstract in the 'Bibliotheque Universelle de Geneve', Poisson has developed +an hypothesis totally different from Fourier's view ('Theorie Analytique de +la Chaleur'.) He denies the present fluid state of the Earth's center; he +believes that "in cooling by radiation to the medium surrounding the Earth, +the parts which were first solidified sunk, and that by a double descending +and ascending current, the great inequality was lessened which would have +taken place in a solid body cooling from the surface." It seems more +probable to this great geometer that the solidification began in the parts +lying nearest to the center: "the phenomenon of the increase of heat with +the depth does not extend to the whole mass of the Earth, and is merely a +consequence of the motion of our planetary system in space, of which some +parts are of a very different temperature from others, in consequence of +stellar heat (chaleur stellaire)." Thus, according to Poisson, the warmth +of the water of our Artesian wells is merely that which has penetrated into +the Earth from without; and the Earth itself "might be regarded as in the +same circumstances as a mass of rock conveyed from the equator to the pole +in so short a time as not to have entirely cooled. The increase of +temperature in such a block would not extend to the central strata." The +physical doubts which have reasonably been entertained against this +extraordinary cosmical view (which attributes to the regions of space that +which probably is more dependent on the first transition of matter +condensing from the gaseo-fluid into the solid state) will be found +collected in Poggendorf's 'Annalen', bd. xxxix., s 93-100. + + +It is with the greatest difficulty that our powers of comprehension can +conceive the boundary line which divides the fluid mass of the interior from +the hardened mineral masses of the external surface, or the gradual increase +of the solid strata, and the condition of semi-fluidity of the earthy +substances, these being conditions to which known laws of hydraulics can +only apply under considerable modifications. The Sun and Moon, which cause +the sea to ebb and flow, most probably also affect these subterranean +depths. We may suppose that the periodic elevations and depressions of the +molten mass under the already solidified strata must have caused +inequalities in the vaulted surface from the force of pressure. The amount +and action of such oscillations must, however, be small; and if the relative +position of the attracting cosmical bodies may here also excite "spring +tides," it is certainly not to these, but to more powerful internal forces, +that we must ascribe the movements that shake the Earth's surface. There +are groups of phenomena to whose existence it is necessary to draw +attention, in order to indicate the universality of the influence of the +attraction of the Sun and Moon on the external and internal conditions of +the Earth, however little we may be able to determine the quantity of this +influence. + +According to tolerably accordant experiments in Artesian wells, it has been +shown that the heat increases on an average about 1 degree for every 54.5 +feet. If this increase can be reduced +p 174 +to arithmetical relations, it will follow, as I have already observed,* that +a stratum of granite would be in a state of fusion at a depth of nearly +twenty-one geographical miles, or between four and five times the elevation +of the highest summit of the Hinalaya. + + +[footnote] *See the Introduction. This increase of temperature has been +found in the Puits de Grenelle, at Paris, at 58.3 feet; in the boring at the +new salt-works at Minden, almost 53.6; at Pregny, near Geneva, according to +Auguste de la Rive and Marcet, notwithstanding that the mouth of the boring +is 1609 feet above the level of the sea, it is also 53.6 feet. This +coincidence between the results of a method first proposed by Arago in the +year 1821 ('Annuaire du Bureau des Longitudes', 1835, p. 234), for three +different mines, of the absolute depths of 1794, 2231, and 725 feet +respectively, is remarkable. The two points on the Earth, lying at a small +vertical distance from each other, whose annual mean temperatures are most +accurately known, are probably at the spot on which the Paris Observatory +stands, and the Caves de l'Observatoire beneath it; the mean temperature of +the former is 51.5ºdegrees, and of the latter 53.3ºdegrees, the difference +being 1.8ºdegrees for 92 feet, or 1 degree for 51.77 feet. (Poisson, +'Theorie Math. de la Chaleur', p. 415 and 462.) In the course of the last +seventeen years, from causes not yet perfectly understood, but probably not +connected with the actual temperature of the caves, the thermometer standing +there has risen very nearly 0.4 degrees. Although in Artesian wells there +are sometimes slight errors from the lateral permeation of water, these +errors are less injurious to the accuracy of conclusions than those +resulting from currents of cold air, which are almost always present in +mines. The general result of Reich's great work on the temperature of the +mines in the Saxony mining districts gives a somewhat slower increase of the +terrestrial heat, or 1 degree to 76.3 feet. (Reich, 'Beob. uber die +Temperatur des Gesteins in verschielen en Tiefen', 1834, s. 134.) Phillips, +however, found (Pogg., 'Annalen', bd. xxxiv., s. 191), in a shaft of the +coal-mine of Monk-wearmouth, near Newcastle, in which, as I have already +remarked, excavations are going on at a depth of about 1500 feet below the +level of the sea, an increase of 1 degree to 59.06 feet, a result almost +identical with that found by Arago in the Puits de Grenell. + + +We must distinguish in our globe three different modes for the transmission +of heat. The first is periodic, and affects the temperature of the +terrestrial strata according as the heat penetrates from above downward or +from below upward, being influenced by the different positions of the Sun +and the seasons of the year. The second is likewise an effect of the Sun, +although extremely slow: a portion of the heat that has penetrated into the +equatorial regions moves in the interior of the globe toward the poles, +where it escapes into the atmosphere and the remoter regions of space. The +third mode of transmission is the slowest of all, and is derived from the +secular cooling of the globe, and from the small portion of the primitive +heat which is still being disengaged from the surface. +p 175 +This loss experienced by the central heat must have been very considerable +in the earliest epochs of the Earth's revolutions, but within historical +periods it has hardly been appreciable by our instruments. The surface of +the Earth is therefore situated between the glowing heat of the inferior +strata and the universal regions of space, whose temperature is probably +below the freezing-point of mercury. + +The periodic changes of temperature which have been occasioned on the +Earth's surface by the Sun's position and by meteorological processes, are +continued in its interior, although to a very inconsiderable depth. The +slow conducting power of the ground diminishes this loss of heat in the +winter, and is very favorable to deep-rooted trees. Points that lie at very +different depths on the same vertical line attain the maximum and minimum of +the imparted temperature at very different periods of time. The further +they are removed from the surface, the smaller is this difference between +the extremes. In the latitudes of our temperate zone (between 48 degrees +and 52 degrees), the stratum of invariable temperature is at a depth of from +59 to 64 feet, and at half that depth the oscillations of the thermometer, +from the influence of the seasons, scarcely amount to half a degree. In +tropical climates this invariable stratum is only one foot below the +surface, and this fact has been ingeniously made use of by Boussingault to +obtain a convenient, and as he believes, certain determination of the mean +temperature of the air of different places.* + + +[footnote] *Boussingault, 'Sur la Profondeus a laquelle se trouve la Couche +de Temperature invariable, entre les Tropiques', in the 'Annales de Chimie +et de Physique', t. liii., 1833, p. 225-247. + + +This mean temperature of the air at a fixed point, or at a group of +contiguous points on the surface, is to a certain degree the fundamental +element of the climate and agricultural relations of a district; but the +mean temperature of the whole surface is very different from that of the +globe itself. The questions so often agitated, whether the mean temperature +has experienced any considerable differences in the course of centuries, +whether the climate of a country has deteriorated, and whether the winters +have not become milder and the summers cooler, can only be answered by means +of the thermometer; this instrument has, however, scarcely been invented +more than two centuries and a half, and its scientific application hardly +dates back 120 years. The nature and novelty of the means interpose, +therefore, very narrow limits to our investigation regarding the temperature +p 176 +of the air. It is quite otherwise, however, with the solution of the great +problem of the internal heat of the whole Earth. As we may judge of +uniformity of temperature from the unaltered time of vibration of a +pendulum, so we may also learn, from the unaltered rotatory velocity of the +Earth, the amount of stability in the mean temperature of our globe. This +insight into the relations between the 'length of the day' and the 'heat of +the Earth' is the result of one of the most brilliant applications of the +knowledge we had long possessed of the planet. The rotatory velocity of the +Earth depends on its volume; and since, by the gradual cooling of the mass +by radiation, the axis of rotation would become shorter, the rotatory +velocity would necessarily increase, and the length of the day diminish, +with a decrease of the temperature. From the comparison of the secular +inequalities in the motions of the Moon with the eclipses observed in +ancient times, it follows that, since the time of Hipparchus, that is, for +full 2000 years, the length of the day has certainly not diminished by the +hundredth part of a second. The decrease of the mean heat of the globe +during a period of 2000 years has not, therefore, taking the extremest +limits, diminished as much as 1/306th of a degree of Fahrenheit.* + + +[footnote] *Laplace, 'Exp. du Syst. du Monde', p. 229 and 263; 'Mecanique +Celeste', t. v., p. 18 and 72. It should be remarked that the fraction +1/306th of a degree of Fahrenheit of the mercurial thermometer, given in the +text as the limit of the stability of the Earth's temperature since the days +of Hipparchus, rests on the assumption that the dilation of the substances +of which the Earth is composed is equal to that of glass, that is to say, +1/18,000th for 1 degree. Regarding this hypothesis, see Arago in the +'Annuaire' for 1834, p. 177-190. + + +This invariability of form presupposes also a great invariability in the +distribution of relations of density in the interior of the globe. The +translatory movements, which occasion the eruptions of our present volcanoes +and of ferruginous lava, and the filling up of previously empty fissures and +cavities with dense masses of stone, are consequently only to be regarded as +slight superficial phenomena affecting merely one portion of the Earth's +crust, which, from their smallness when compared to the Earth's radius, +become wholly insignificant. + +I have described the internal heat of our planet, both with reference to its +cause and distribution, almost solely from the results of Fourier's +admirable investigations. Poisson doubts the fact of the uninterrupted +increase of the Earth's heat +p 177 +from the surface to the center, and is of opinion that all heat has +penetrated from without inward, and that the temperature of the globe +depends upon the very high or very low temperature of the regions of space +through which the solar temperature of the regions of space, through which +the solar system has moved. This hypothesis, imagined by one of the most +acute mathematicians of our time, has not satisfied physicists or +geologists, or scarcely indeed any one besides its author. But, whatever +may be the cause of the internal heat of our planet, and of its limited or +unlimited increase in deep strata, it leads us, in this general sketch of +nature, through the intimate connection of all primitive phenomena of +matter, and through the common bond by which molecular forces are united, +into the mysterious domain of magnetism. Changes of temperature call forth +magnetic and electric currents. Terrestrial magnetism, whose main +character, expressed in the three-fold manifestation of its forces, is +incessant periodic variability, is ascribed either to the heated mass of the +Earth itself,* or to those galvanic currents which we consider as +electricity in motion, that is, electricity moving in a closed circuit.** + + +[footnote] *William Gilbert, of Colchester, whom Galileo pronounced "great +to a degree that might be envied," said "magnus magnes ipse est globus +terrestris." He ridicules the magnetic mountains of Frascatori, the great +contemporary of Columbus, as being magnetic poles: "rejicienda est vulgaris +opinio de montibus magneticis, aut rupe aliqua magnetica, aut polo +phantastico a polo mundi distante." He assumes the declination of the +magnetic needle at any give point on the surface of the Earth to be +invariable (variatio uniuscujusque loci constans est), and refers the +curvatures of the isogonic lines to the configuration of continents and the +relative positions of sea basins, which possess a weaker magnetic force than +the solid masses rising above the ocean. (Gilbert, 'de Magnete', ed. 1633, +p. 42, 98, 152 and 155.) + + +[footnote] ** Gauss, 'Allgemcine Theorie des Erdmagnetismus', in the +'Resultate aux den Beob. des Magnet. Vereins', 1838, s. 41, p. 56. + + +The mysterious course of the magnetic needle is equally affected by time and +space, by the sun's course, and by changes of place on the Earth's surface. +Between the tropics, the hour of the day may be known by the direction of +the needle as well as by the oscillations of the barometer. It is affected +instantly, but only transiently, by the distant northern light as it shoots +from the pole, flashing in beams of colored light across the heavens. When +the uniform horary motion of the needle is disturbed by a magnetic storm, +the perturbation manifests itself 'simultaneously', in the strictest sense +of the word, over hundreds and thousands of miles of sea and land, or +propagates itself by degrees, in short intervals of time, in +p 178 +every direction over the Earth's surface.* + + +[footnote] *There are also perturbations which are of a local character, +and do not extend themselves far, and are probably less deep-seated. Some +years ago I described a rare instance of this kind, in which an +extraordinary disturbance was felt in the mines at Freiberg, but was not +perceptible at Berlin. ('Lettre de M. de Humboldt a Son Altesse Royale le +Duc de Sussex sur les moyens propres a perfectionner la Connaissance du +Magnetisme Terrestre', in Becquerel's 'Traite Experimental de l'Electricite' +t. vii., p. 442.) Magnetic storms which were simultaneously felt from +Sicily to Upsala, did not extend from Upsala to Alten. (Gauss and Weber, +'Resultate des Magnet. Vereins', 1839, 128; Lloyd, in the 'Comptes Rendus de +l'Acad. des Sciences', t. xii., 1843, Sem. ii., p. 725 and 827.) Among the +numerous examples that have been recently observed, of perturbations +occurring simultaneously and extending over wide portions of the Earth's +surface, and which are collected in Sabine's important work ('Observ. on +Days of unusual Magnetic Disturbance', 1843), one of the most remarkable is +that of the 25th of September, 1841, which was observed at Toronto in +Canada, at the Cape of Good Hope, at Prague, and partially in Van Diemen's +Land. The English Sunday, on which it is deemed sinful, after midnight on +Saturday, to register an observation, and to follow out the great phenomena +of creation in their perfect development, interrupted the observations in +Van Diemen's Land, where in consequence of the difference of the longitude, +the magnetic storm fell on the Sunday. ('Observ.', p. xiv., 78, 85, and 87.) + + +In the former case, the simultaneous manifestation of the storm may serve, +within certain limitations, like Jupiter's satellites, fire-signals, and +well-observed falls of shooting stars, for the geographical determination of +degrees of longitude. We here recognize with astonishment that the +perturbations of two small magnetic needles, even if suspended at great +depths below the surface, can measure the distances apart at which they are +placed, teaching us, for instance, how far Kasan is situated east of +Gottingen or of the banks of the Seine. There are also districts in the +earth where the mariner, who has been enveloped for many days in mist, +without seeing either the sun or stars, and deprived of all means of +determining the time, may know with certainty, from the variations in the +inclination of the magnetic needle, whether he is at the north or the south +of the port he is desirous of entering.* + + +[footnote] *I have described, in Lametherie's 'Journal de Physique', 1804, +t. lix., p. 449, the application (alluded to in the text) of the magnetic +inclination to the determination of latitude along a coast running north and +south, and which, like that of Chili and Peru, is for a part of the year +enveloped in mist ('garua'). In the locality I have just mentioned, this +application is of the greater importance, because, in consequence of the +strong current running northward as far as to Cape Parena, navigators incur +a great loss of time if they approach the coast to the north of the haven +they are seeking. In the South Sea, from Callao de Lima harbor to Truxillo, +which differ from each other in latitude by 3 degrees 57' I have observed a +variation of the magnetic inclination amounting to 9 degrees (centesimal +division); and from Callao to Guayaquil, which differ in latitude by 9 +degrees 50', a variation of 23.5 degrees. (See my 'Relat. Hist.', t. iii., +p. 622.) At Guarmey (10 degrees 4' south lat.), Huaura (11 degrees 3' south +lat.), and Chancay (11 degrees 4' south lat.), Huaura (11 degrees 3' south +lat.), and Chancay (11 degrees 32' south lat.), the inclinations are 6.80 +degrees, 9 degrees, and 10.35 degrees of the centesimal division. The +determination of position by means of the magnetic inclination has this +remarkable feature connected with it, that where the ship's course cuts the +isoclinalline almost perpendicularly, it is the only one that is independent +of all determination of time, and consequently, of observations of the sun +or stars. It is only lately that I discovered, for the first time, that as +early as at the close of the sixteenth century, and consequently hardly +twenty years after Robert Norman had invented the inclinatorium, William +Gilbert, in his great work, 'De Magnete', proposed to determine the latitude +by the inclination of the magnetic needle. Gilbert ('Physiologia Nova de +Magnete', lib. v., cap. 8, p. 200) commends the method as applicable "aëre +caliginoso." Edward Wright, in the introduction which he added to his +master's great work, describes this proposal as "worth much gold." As he +fell into the same error with Gilbert, of presuming that the isoclinal lines +coincided with the geographical parallel circles, and that the magnetic and +geographical equators were identical, he did not perceive that the proposed +method had only a local and very limited application. + + +p 179 +When the needle, by its sudden disturbance in its horary course, indicates +the presence of a magnetic storm, we are still unfortunately ignorant +whether the seat of the disturbing cause is to be sought in the Earth itself +or in the upper regions of the atmosphere. If we regard the Earth as a true +magnet, we are obliged, according to the views entertained by Friedrich +Gauss (the acute propounder of a generaltheory of terrestrial magnetism), to +ascribe to every portion of the globe measuring one eighth of a cubic meter +(or 3 7/10ths of a French cubic foot) in volume, an average amount of +magnetism equal to that contained in a magnetic rod of 1 lb. weight.* + + +[footnote[ *Gauss and Weber, 'Resultate des Magnet. Vereins', 1838, 31, s. +146. + + +If iron and nickel, and probably, also, cobalt (but not chrome, as has long +been believed),* are the only substances which become permanently magnetic, +and retain polarity from a certain coerceive force, the phenomena of Arago's +magnetism of rotation and of Faraday's induced currents show, on the other +hand, that all telluric substances may possibly be made transitorily +magnetic. + + +According to Faraday ('London and Edinburgh Philosophical Magazine', 1836, +vol. viii., p. 178), pure cobalt is totally devoid of magnetic power. I +know, however, that other celebrated chemists (Heinrich Rose and Wohler) do +not admit this as absolutely certain. If out of two carefully-purified +masses of cobalt totally free from nickel, one appears altogether +non-magnetic (in a state of equilibrium), I think it probable that the other +owes its magnetic property to a want of purity; and this opinion coincides +with Faraday's view. + + +According to the experiments of the +p 180 +first-mentioned of these great physicists, water, ice, glass, and carbon +affect the vibrations of the needle entirely in the same manner as mercury +in the rotation experiments.* + + +[footnote] *Arago, in the 'Annales de Chimie', t. xxxii., p. 214; Brewster, +'Treaties on Magnetism', 1837, p. 111; Baumgartner, in the 'Zeitschrift fur +Phys. und Mathem.', bd. ii., s. 419. + + +Almost all substances show themselves to be, in a certain degree, magnetic +when they are conductors, that is to say, when a current of electricity is +passing through them. + +Although the knowledge of the attracting power of native iron magnets or +loadstones appears to be of very ancient date among the nations of the West, +there is strong historical evidence in proof of the striking fact that the +knowledge of the directive power of a magnetic needle and of its relation to +terrestrial magnetism was peculiar to the Chinese, a people living in the +extremest eastern portions of Asia. More than a thousand years before our +era, in the obscure age of Codrus, and about the time of the return of the +Heraclidae to the Peloponnesus, the Chinese had already magnetic carriages, +on which the movable arm of the figure of a man continually pointed to the +south, as a guide by which to find the way across the boundless grass plains +of Tartary; nay, even in the third century of our era, therefore at least +700 years before the use of the mariner's compass in European seas, Chinese +vessels navigated the Indian Ocean* under the direction of magnetic needles +pointing to the south. + + +[footnote] *Humboldt, 'Examen Critique de l'Hist. de la Geographie', t. +iii., p. 36. + + +I have shown, in another work, what advantages this means of topographical +direction, and the early knowledge and application of the magnetic needle +gave the Chinese geographers over the Greeks and Romans, to whom, for +instance, even the true direction of the Apennines and Pyrenees always +remained unknown.* + + +[footnote] *'Asie Centrale', t. i., Introduction, p. xxxviii-xlii. The +Western nations, the Greeks and the Romans, knew that magnetism could be +communicated to iron, 'and that that metal would retain it for a length of +time'. ("Sola haec materia ferri vires, a maguete lapide accipit, +'retinetque longo tempore." Plin., xxxiv., 14.) The great discovery of the +terrestrial directive force depended, therefore, alone on this, that no one +in the West had happened to observe an elongated fragment of magnetic iron +stone, or a magnetic iron rod, floating, by the aid of a piece of wood, in +water, or suspended in the air by a thread, in such a position as to admit +of free motion. + + +The magnetic power of our globe is manifested on the terrestrial surface in +three classes of phenomena, one of which exhibits itself in the varying +intensity of the force, and the two others in the varying direction of the +inclination, and in +p 181 +the horizontal deviation from the terrestrial meridian of the spot. Their +combined action may therefore be graphically represented by three systems of +lines, the 'isodynamic, isoclinic', and 'isogonic' (or those of equal force, +equal inclination, and equal declination). The distances apart, and the +relative positions of these moving, oscillating, and advancing curves, do +not always remain the same. The total deviation (variation or declination +of the magnetic needle) has not at all changed, or, at any rate, not in any +appreciable degree, during a whole century, at any particular point on the +Earth's surface,* as, for instance, the western part of the Antilles, or +Spitzbergen. + + +[footnote] *A very slow secular progression, or a local invariability of +the magnetic declination, prevents the confusion which might arise from +terrestrial influences in the boundaries of land, when, with an utter +disregard for the correction of declination, estates are, after long +intervals, measured by the mere application of the compass. "The whole mass +of the bottomless pit of endless litigation by the invariability of the +magnetic declination in Jamica and the surrounding Archipelago during the +whole of the last century, all surveys of property there having been +conducted solely by the compass." See Robertson in the 'Philosophical +Transactions' for 1806, Part ii., p. 348, 'On the Permanency of the Compass +in Jamaica since 1660'. In the mother country (England) the magnetic +declination has varied by fully 14 degrees during the period. + + +In like manner, we observe that the isogonic curves, when they pass in their +secular motion from the surface of the sea to a continent or an island of +considerable extent, continue for a long time in the same position, and +become inflected as they advance. + +These gradual changes in the forms assumed by the lines in their translatory +motions, and which so unequally modify the amount of eastern and western +declination, in the course of time render it difficult to trace the +transitions and analogies of forms in the graphic representations belonging +to different centuries. + +Each branch of a curve has its history, but this history does not reach +further back among the nations of the West than the memorable epoch of the +13th of September, 1492, when the re-discoverer of the New World found a +line of no variation 3 degrees west of the meridian of the island of Flores, +one of the Azores.* + + +[footnote] *I have elsewhere shown that, from the documents which have come +down to us regarding the voyages of Columbus, we can, with much certainty, +fix upon three places 'in the Atlantic line of no declination' for the 13th +of September, 1492, the 21st of May, 1496, and the 16th of August, 1498. +The Atlantic line of no declination at that period ran from northeast to +southwest. It then touched the South American continent a little east of +Cape Codera, while it is not observed to reach that continent on the +northern coast of the Brazils. (Humboldt, 'Examen Critique de l'Hist. de la +Geogr.', t. iii., p. 44-48.) From Gilbert's 'Physiologia Nova de Magnete', +we see plainly (and the fact is very remarkable) that in 1600 the +declination was still null in the region of the Azores, just as it had been +in the time of Columbus (lib. 4, cap. 1). I believe that in my 'Examen +Critique' (t. iii., p. 54) I have proved from documents that the celebrated +line of demarkation by which Pope Alexander VI. divided the Western +hemisphere between Portugal and Spain was not drawn through the most western +point of the Azores, because Columbus wished to convert a physical into a +political division. He attached great importance to the zone (raya) "in +which the compass shows no variation, where air and ocean, the later covered +with pastures of sea-weed, exhibit a peculiar constitution, where cooling +winds begin to blow, and where [as erroneous observations of the polar star +led him to imagine] the form (sphericity) of the Earth is no longer the +same." + +The whole of Europe, excepting a small +p 182 +part of Russia, has now a western declination, while at the close of the +seventeenth century the needle first pointed due north, in London in 1657, +and in Paris in 1669, there being thus a difference of twelve years, +notwithstanding the small distance between these two places. In Eastern +Russia, to the east of the mouth of the Volga, of Saratow, Nischni-Nowgorod, +and Archangel, the easterly declination of Asia is advancing toward us. Two +admirable observers, Hansteen and Adolphus Erman, have made us acquainted +with the remarkable double curvature of the lines of declination in the vast +region of Northern Asia; these being concave toward the pole between +Obdorsk, on the Oby, and Turuchansk, and convex between the Lake of Baikal +and the Gulf of Ochotsk. In this portion of the earth, in northern Asia, +between the mountains of Werchojansk, Jakutsk, and the northern Korea, the +isogonic lines form a remarkable closed system. This oval configuration* +recurs regularly and over a great extent of the South Sea, almost as far as +the meridian of Pitcairn and the group of the Marquesas Islands, between 20 +degrees north and 45 degrees +p 183 +south lat. + + +[footnote] *To determine whether the two oval systems of isogonic lines, so +singularly included each within itself, will continue to advance for +centuries in the same inclosed form, or will unfold and expand themselves, +is a question of the highest interest in the problem of the physical causes +of terrestrial magnetism. In the Eastern Asiatic nodes the declination +increases from without inward, while in the node or oval system of the South +Sea the opposite holds good; in fact, at the present time, in the whole +South Sea to the east of the meridian of Kamt-schatka, there is no line +where the declination is null, or, indeed, in which it is less than 2 +degrees (Erman, in Pogg., 'Annal.', bd. xxxi, 129). Yet Cornelius Schouten, +on Easter Sunday, 1616, appears to have found the declination null somewhere +to the southeast of Nukahiva, in 15 degrees south lat. and 132 degrees west +long., and consequently in the middle of the present closed isogonal system. + (Hansteen, 'Magnet. der Erde', 1819 § 28.) It must not be forgotten, in +the midst of all these considerations, that we can only follow the direction +of the magnetic lines in their progress as they are projected upon the +surface of the Earth. + + +One would almost be inclined to regard this singular configuration of +closed, almost concentric, lines of declination as the effect of a local +character of that portion of the globe; but if, in the course of centuries, +these apparently isolated systems should also advance, we must suppose, as +in the case of all great natural forces, that the phenomenon arises from +some general cause. + +The horary variations of the declination, which, although dependent upon +true time, are apparently governed by the Sun, as long as it remains above +the horizon, diminish in angular value with the magnetic latitude of place. +Near the equator, for instance, in the island of Rawak, they scarcely amount +to three or four minutes, while they are from thirteen to fourteen minutes +in the middle of Europe. As in the whole northern hemisphere the north +point of the needle moves from east to west on an average from 8 1/2 in the +morning until 1 1/2 at mid-day, while in the southern hemisphere the same +north point moves from west to east,* attention has recently been drawn, +with much justice, to the fact that there must be a region of the Earth +between the terrestrial and the magnetic equator where no horary deviations +in the declination are to be observed. + + +[footnote] *Arago, in the 'Annuaire', 1836, p. 284, and 1840, p. 330-338. + + +This fourth curve, which might be called the 'curve of no motion', or, +rather, 'the line of no variation of horary declination', has not yet been +discovered. + +The term 'magnetic poles' has been applied to those points of the Earth's +surface where the horizontal power disappears, and more importance has been +attached to these points than properly appertains to them;* and in like +manner, the curve, where the inclination of the needle is null, has been +termed the 'magnetic equator'. + + +[footnote] *Gauss, 'Allg. Theorie des Erdmagnet.', 31. + + +The position of this line and its secular change of configuration have been +made an object of careful investigation in modern times. According to the +admirable work of Duperrey,* who crossed the magnetic equator six times +between 1822 and 1825, the nodes of the two equators, that is to say, the +two points at which the line without inclination intersects the terrestrial +equator, and consequently passes from one henisphere into the other, are so +unequally placed, that in 1825 the node near the island of St. Thomas, on +the western +p 184 +coast of Africa, was 188 1/2 degrees distant from the node in the South Sea, +close to the little islands of Gilbert, nearly in the meridian of the Viti +group. + + +[footnote] *Duperrey, 'De la Configuration de l'Equateur Magnetique', in +the 'Annales de Chimie', t. xlv., p. 371 and 379. (See also, Morlet, in the +'Memoires presentes par divers Savans a l'Acad. Roy. des Sciences', t. iii., +p. 132. + + +In the beginning of the present century, at an elevation of 11,936 feet +above the level of the sea, I made an astronomical determination of the +point (7 degrees 1' south lat., 48 degrees 40' west long. from Paris), +where, in the interior of the New Continent, the chain of the Andes is +intersected by the magnetic equator between Quito and Lima. To the west of +this point, the magnetic equator continues to traverse the South Sea in the +southern hemisphere, at the same time slowly drawing near the terrestrial +equator. It first passes into the northern hemisphere a little before it +approaches the Indian Archipelago, just touches the southern points of Asia, +and enters the African continent to the west of Socotora, almost in the +Straits of Bab-el-Mandeb, where it is most distant from the terrestrial +equator. After intersecting the unknown regions of the interior of Africa +in a southwest direction, the magnetic equator re-enters the south tropical +zone in the Gulf of Guinea, and retreats so far from the terrestrial equator +that it touches the Brazilian coast near Os Ilheos, north of Porto Seguro, +in 15 degrees south lat. From thence to the elevated plateaux of the +Cordilleras, between the silver mines of micuipampa and Caxamarca, the +ancient seat of the Incas, where I observed the inclination, the line +traverses the whole of South America, which in these latitudes is as much a +magnetic 'terra incognita' as the interior of Africa. + +The recent observations of Sabine* have shown that the node near the island +of St. Thomas has moved 4 degrees from east to west between 1825 and 1837. + + +[footnote] *See the remarkable chart of isoclinic lines in the Atlantic +Ocean for the years 1825 and 1837, in Sabine's 'Contributions to Terrestrial +Magnetism', 1840, p. 134. + + +It would be extremely important to know whether the opposite pole, near the +Gilbert Islands, in the South Sea, has aproached the meridian of the +Carolinas in a westerly direction. These general remarks will be sufficient +to connect the different systems of isoclinic non-parallel lines with the +great phenomenon of equilibrium which is manifested in the magnetic equator. + It is no small advantage, in the exposition of the laws of terrestrial +magnetism, that the magnetic equator (whose oscillatory change of form and +whose nodal motion exercise an influence on the inclination of the needle in +the remotest districts of the world, in consequence of the altered magnetic +latitudes)* should traverse the +p 185 +ocean throughout its whole course, excepting about one fifth, and +consequently be made so much more accessible, owing to the remarkable +relations in space between the sea and land, and to the means of which we +are now possessed for determining with much exactness both the declination +and the inclination at sea. + + +[footnote] *Humboldt, 'Ueber die seculäre Veränderung der Magnetischen +Inclination' (On the secular Change in the Magnetic Inclination), in Pogg. +'Annal.', bd. sv., s. 322. + +We have described the distribution of magnetism on the surface of our planet +according to the two forms of 'declination' and 'inclination'; it now, +therefore, remains for us to speak of the 'intensity of the force' which is +graphically expressed by isodynamic curves (or lines of equal intensity). +The investigation and measurement of this force by the oscillations of a +vertical or horizontal needle have only excited a general and lively +interest in its telluric relations since the beginning of the nineteenth +century. The application of delicate optical and chronometrical instruments +has rendered the measurement of this horizontal power susceptible of a +degree of accuracy far surpassing that attained in any other magnetic +determinations. The isogonic lines are the more important in their +immediate application to navigation, while we find from the most recent +views that isodynamic lines, especially those which indicate the horizontal +force, are the most valuable elements in the theory of terrestrial +magnetism.* + + +[footnote] *Gauss, 'Resultate der Beob. des Magn. Vereins', 1838, 21; +Sabine, 'Report on the Variations of the Magnetic Intensity', p. 63. + + +One of the earliest facts yielded by observation is, that the intensity of +the total force increases from the equator toward the pole.* + + +[footnote] *The following is the history of the discovery of the law that +the intensity of the force increases (in general) with the magnetic +latitude. When I was anxious to attach myself, in 1798, to the expedition +of Captain Bandin, who intended to circumnavigate the globe, I was requested +by Borda, who took a warm interest in the success of my project, to examine +the oscillations of a vertical needle in the magnetic meridian in different +latitudes in each hemisphere, in order to determine whether the intensity of +the force was the same, or whether it varied in different places. During my +travels in the tropical regions of America, I paid much attention to this +subject. I observed that the same needle, which in the space of ten minutes +made 245 oscillations in Paris, 246 in the Havana, and 242 in Mexico, +performed only 216 oscillations during the same period at St. Carlos del Rio +Negro (1 degree 53' north lat. and 80 degrees 40' west long. from Paris), on +the magnetic equator, i.e., the line in which the inclination =0; in Peru (7 +degrees 1' south lat. and 80 degrees 40' west long. from Paris) only +211;while at Lima (12 degrees 2' south lat.) the number rose to 219. I +found, in the years intervening between 1799 and 1803, that the whole force, +if we assume it at 1.0000 on the magnetic equator in the Peruvian Andes, +between Micuipampa and Caxamarca, may be expressed at Paris by 1.3482, in +Mexico by 1.3155, in San Carlos del Rio Negro by 1.0480, and in Lima by +1.0773. When I developed this law of the variable intensity of terrestrial +magnetic force, and supported it by the numerical value of observations +instituted in 104 different places, in a Memoir read before the Paris +Institute on the 26th Frimaire, An. XIII. (of which the mathematical portion +was contributed by M. Biot), the facts were regarded as altogether new. It +was only after the reading of the paper, as Biot expressly states +(Lametherie, 'Journal de Physique', t. lix., p. 446, note 2) and as I have +repeated in 'the Relation Historique', t. i., p. 262, note 1, that M. de +Rossel communicated to Biot his oscillation experiments made six years +earlier (between 1791 and 1794) in Van Diemen's Land, in Java, and in +Amboyna. These experiments gave evidence of the same law of decreasing +force in the Indian Archipelago. It must, I think be supposed, that this +excellent man, when he wrote his work, was not aware of the regularity of +the augmentation and diminution of the intensity as before the reading of my +paper he never mentioned this (certainly not unimportant) physical law to +any of our mutual friends, La Place, Delambre, Prony, or Biot. It was not +till 1808, four years after my return from America that the observations +made by M. de Rossel were published in the 'Voyage de l'Entrecasteaux', t. +ii., p. 287 , 291, 321, 480, and 644. Up to the present day it is still +usual, in all the tables of magnetic intensity which have been published in +Germany (Hausteen, 'Magnet. der Erde', 1819, s. 71; Gauss, 'Beob. des +Magnet. Vereins', 1838, s. 36-39; Erman, 'Physikal. Beob.', 1841, s. +529-579), in England (Sabine, 'Report on Magnet. Intensity', 1838, p. 43-62; +'Contributions to Terrestrial Magnetism', 1843), and in France (Becquerel, +'Traite de Electr. et de Magnet.', t. vii., p. 354-367), to reduce the +oscillations observed in any part of the Earth to the standard of force +which I found on the magnetic equator in Northern Peru, so that, according +to the unit thus arbitrarily assumed, the intensity of the magnetic force at +Paris is put down as 1.348. The observations made by Lamanon in the +unfortunate expedition of La Perouse, during the stay at Teneriffe (1785), +and on the voyage to Macao (1787), are still older than those of Admiral +Rossel. They were sent to the Academy of Sciences, and it is known that +they were in the possession of Condorcet in the July of 1787 (Becquerel, t. +vii., p. 320); but, notwithstanding the most careful search, they are not +now to be found. From a copy of a very important letter of Lamanon, now in +the possession of Captain Duperrey, which was addressed to the then +perpetual secretary of the Academy of Sciences, but was omitted in the +narrative of the 'Voyage de La Perouse', it is stated "that the attractive +force of the magnet is less in the tropics than when we approach the poles, +and that the magnetic intensity deduced from the number of oscillations of +the needle of the inclination-compass varies and increases with the +latitude." If the Academicians, while they continued to expect the return +of the unfortunate La Perouse, had felt themselves justified, in the course +of 1787, in publishing a truth which had been independently discovered by no +less than three different travelers, the theory of terrestrial magnetism +would have been extended by the knowledge of a new class of observations, +dating eighteen years earlier than they now do. This simple statement of +facts may probably justify the observations contained in the third volume of +my 'Relation Historique' p. 615): "The observations on the variation of +terrestrial magnetism, to which I have devoted myself for thirty-two years, +by means of instruments which admit of comparison with one another, in +America, Europe, and Asia, embrace an area extending over 188 degrees of +longitude, from the frontier of Chinese Dzoungarie to the west of the South +Sea bathing the coasts of Mexico and Peru, and reaching from 60 degrees +north lat. to 12 degrees south lat. I regard the discovery of the law of +the decrement of magnetic force from the pole to the equator as the most +important result of my American voyage." Although not absolutely certain, +it is very probable that Condorcet read Lamanon's letter of July, 1787, at a +meeting of the Paris Academy of Sciences; and such a simple reading I regard +as a sufficient act of publication. ('Annuaire du Bureau des Longitudes', +1842, p. 463.) The first recognition of the law belongs, therefore, beyond +all question, to the comparison of La Perouse; but, long disregarded or +forgotten, the knowledge of the law that the intensity of the magnetic force +of the Earth varied with the latitude, did not, I conceive, acquire an +existence in science until the publication of my observations from 1798 to +1804. The object and the length of this note will not be indifferent to +those who are familiar with the connection with it, and who, from their own +experience, are aware that we are apt to attach some value to that which has +cost us the uninterrupted labor of five years, under the pressure of a +tropical climate, and of perilous mountain expeditions. + + +p 186 +The knowledge which we possess of the quantity of this increase, and of all +the numerical relations of the law of intensity +p 187 +affecting the whole Earth, is especially due, since 1819, to the unwearied +activity of Edward Sabine, who, after having observed the oscillations of +the same needles at the American north pole, in Greenland, at Spitzbergen, +and on the coasts of Guinea and Brazil, has continued to collect and arrange +all the facts capable of explaining the direction of the isodynamic system +in zones for a small part of South America. These lines are not parallel to +lines of equal inclination (isoclinic line), and the intensity of the force +is not at its minimum at the magnetic equator, as has been supposed, nor is +it even equal at all parts of it. If we compare Erman's observations in the +southern part of the Atlantic Ocean, where a faint zone (0.706) extends from +Angola over the island of St. Helena to the Brazilian coast, with the most +recent investigations of the celebrated navigator James Clark Ross, we shall +find that on the surface of our planet the force increases almost in the +relation of 1:3 toward the magnetic south pole, where Victoria Land extends +from Cape Crozier toward the volcano Erebus, which has been raised to an +elevation of 12,600 feet above the ice.* + + +[footnote] *From the observations hitherto collected, it appears that the +maximum of intensity for the whole surface of the Earth is 2.052, and the +minimum 0.706. Both phenomena occur in the southern hemisphere; the former +in 73 degrees 47' S. lat., and 169 degrees 30'E. long. from Paris, near +Mount Crozier, west-northwest of the south magnetic pole, at a place where +Captain James Ross found the inclination of the needle to be 87 degrees 11' +(Sabine, 'Contributions to Terrestrial Magnetism', 1843, No. 5, p. 231); the +latter, observed by Erman at 19 degrees 59' S. lat., and 37 degrees 24' W. +long. from Paris, 320 miles eastward from the Brazilian coast of Espiritu +Santo (Erman, 'Phys. Beob.', 1841, s. 570), at a point where the inclination +is only 7 degrees 55'. The actual ratio of the two intensities is therefore +as 1 to 2.906. It was long believed that the greatest intensity of the +magnetic force was only two and a half times as great as the weakest +exhibited on the Earth's surface. (Sabine, 'Report on Magnetic Intensity', +p. 82.) + + +If the intensity near the magnetic south pole +p 188 +be expressed by 2.052 (the unit still employed being the intensity which I +discovered on the magnetic equator in Northern Peru), Sabine found it was +only 1.624 at the magnetic north pole near Melville Island (70 degrees 27' +north lat.), while it is 1.803 at New York, in the United States, which has +almost the same latitude as Naples. + +The brilliant discoveries of Oersted, Arago, and Faraday have established a +more intimate connection between the electric tension of the atmosphere and +the magnetic tension of our terrestrial globe. While Oestred has discovered +that electricity excites magnetism in the neighborhood of the conducting +body, Faraday's experiments have elicited electric currents from the +liberated magnetism. Magnetism is one of the manifold forms under which +electricity reveals itself. The ancient vague presentiment of the identity +of electric and magnetic attraction has been verified in our own times. +"When electrum (amber)," says Pliny, in the spirit of the Ionic natural +philosophy of Thales,* is 'animated' by friction and heat, it will attract +bark and dry leaves precisely as the loadstone attracts iron." + + +[footnote] *Of amber (succinum, glessum) Pliny observes (xxxvii., 3), +"Genera ejus plura. Attritu digitorum accepta caloris anima trahunt in se +paleas ac folia arida quae levia sunt, ac ut magnes lapis ferri ramenta +quoque." (Plato, 'in Timaeo', p. 80. Martin, 'Etude sur le Timee', t. ii., +p. 343-346. Strabo, xv., p. 703, Casaub,; Clemens Alex., 'Strom.', ii., p. +370, where, singularly enough, a difference is made between [Greek words]) +When Thales, in Aristot., 'de Anima', 1, 2, and Hippias, in Diog. Laert., +i., 24, describe the magnet and amber as possessing a soul, they refer only +to a moving principle. + + +The same words may be found in the literature of an Asiatic nation, and +occur in a eulogium on the loadstone by the Chinese physicist Kuopho.* + + +[footnote] *"The magnet attracts iron as amber does the smallest grain of +mustard seed. It is like a breath of wind which mysteriously penetrates +through both, and communicates itself with the rapidity of an arrow." These +are the words of Kuopho, a Chinese panegyrist on the magnet, who wrote in +the beginning of the fourth century. (Klaproth, 'Lettre a M. A. de Humboldt, +sur l'Invention de la Boussole', 1834, p. 125.) + +I observed with astonishment, +p 189 +on the woody banks of the Orinoco, in the sports of the natives, that the +excitement of electricity by friction was known to these savage races, who +occupy the very lowest place in the scale of humanity. Children may be seen +to rub the dry, flat, and shining seeds or husks of a trailing plant +(probably a 'Negretia') until they are able to attract threads of cotton and +pieces of bamboo cane. That which thus delights the naked copper-colored +Indian is calculated to awaken in our minds a deep and earnest impression. +What a chasm divides the electric pastime of these savages from the +discovery of a metallic conductor discharging its electric shocks, or a pile +composed of many chemically-decomposing substances, or a light-engendering +magnetic apparatus! In such a chasm lie buried thousands of years that +compost the history of the intellectual development of mankind! + +The incessant change or oscillatory motion which we discover in all magnetic +phenomena, whether in those of the inclincation, declination, and intensity +of these forces, according to the hours of the day and the night, and the +seasons and the course of the whole year, leads us to conjecture the +existence of very various and partial systems of electric currents on the +surface of the Earth. Are these currents, as in Seebeck's experiments, +thermo-magnetic, and excited directly from unequal distribution of heat? or +should we not rather regard them as induced by the position of the Sun and +by solar heat?* + + +[footnote] *"The phenomena of periodical variations depend manifestly on +the action of solar heat, operating probably through the medium of +thermo-electric currents induced on the Earth's surface. Beyond this rude +guess, however, nothing is as yet known of their physical cause. It is even +still a matter of speculation whether the solar influence be a principal or +only a subordinate cause in the phenomena of terrestrial magnetism." +('Observations to be made in the Antarctic Expedition', 1840, p. 35.) + + +Have the rotation of the planets, and the different degrees of velocity +which the individual zones acquire, according to their respective distances +from the equator, any influence on the distribution of magnetism? Must we +seek the seat of these currents, that is to say, of the disturbed +electricity, in the atmosphere, in the regions of planetary space, or in the +polarity of the Sun and Moon? Galileo, in his celebrated 'Dialogo', was +inclined to ascribe the parallel direction of the axis of the Earth to a +magnetic point of attraction seated in universal space. + +If we represent to ourselves the interior of the Earth as fused and +undergoing an enormous pressure, and at a degree of temperature the amount +of which we are unable to assign, +p 190 +we must renounce all idea of a magnetic nucleus of the Earth. All magnetism +is certainly not lost until we arrive at a white heat,* and it is manifested +when iron is at a dark red heat, however different, therefore, the +modifications may be which are excited in substances in their molecular +state, and in the coercive force depending upon that condition in +experiments of this nature, there will still remain a considerable thickness +of the terrestrial stratum, which might be assumed to be the seat of +magnetic currents. + + +[footnote] *Barlow, in the 'Philos. Trans.' for 1822, Pt. i., p. 117; Sir +David Brewster, 'Treatise on Magnetism', p. 129. Long before the times of +Gilbert and Hooke, it was taught in the Chinese work 'Ow-thea-tsou' that +heat diminished the directive force of the magnetic needle. (Klaproth, +'Lettre a M. A. de Humboldt, sur l'Invention de la Boussole', p. 96.) + + +The old explanation of the horary variations of declination by the +progressive warming of the Earth in the apparent revolution of the Sun from +east to west must be limited to the uppermost surface, since thermometers +sunk into the Earth, which are now being accurately observed at so many +different places, show how slowly the solar heat penetrates even to the +inconsiderable depth of a few feet. Moreover, the thermic condition of the +surface of water, by which two thirds of our planet is covered, is not +favorable to such modes of explanation, when we have reference to an +immediate action and not to an effect of induction in the aërial and +aqueous investment of our terrestrial globe. + +In the present condition of our knowledge, it is impossible to afford a +satisfactory reply to all questions regarding the ultimate physical causes +of these phenomena. It is only with reference to that which presents itself +in the triple manifestations of the terrestrial force, as a measurable +relation of space and time, and as a stable element in the midst of change, +that science has recently made such brilliant advances by the aid of the +determination of mean numerical values. From Toronto in Upper Canada to the +Cape of Good Hope and Van Diemen's Land, from Paris to Pekin, the Earth has +been covered, since 1828, with magnetic observatories,* in which every +regular +p 191 +or irregular manifestation of the terrestrial force is detected by +uninterrupted and simultaneous observations. A variation +p 192 +of 1/40000th of the magnetic intensity is measured, and at certain epochs, +observations are made at intervals of 2 1/2 minutes, and continued for +twenty-four hours consecutively. + + +[footnote] *As the first demand for the establishment of these +observatories (a net-work of stations, provided with similar instruments) +proceeded from me, I did not dare to cherish the hope that I should live +long enough to see the time when both hemispheres should be uniformly +covered with magnetic houses under the associated activity of able +physicists and astronomers. This has, however, been accomplished, and +chiefly through the liberal and continued support of the Russian and British +governments. + +[footnote continues] In the years 1806 and 1807, I and my friend and +fellow-laborer, Herr Oltmanns, while at Berlin, observed the movements of +the needle, especially at the times of the solstices and equinoxes, from +hour to hour, and often from half hour to half hour, for five or six days +and nights uninterruptedly. I had persuaded myself that continuous and +uninterrupted observations of several days and nights (observatio perpetua) +were preferable to the single observations of many months. The apparatus, a +Prony's magnetic telescope, suspended in a glass case by a thread devoid of +torsion, allowed angles of seven or eight seconds to be read off on a +finely-divided scale, placed at a proper distance, and lighted at night by +lamps. Magnetic perturbations (storms), which occasionally recurred at the +same hour on several successive nights, led me even then to desire extremely +that similar apparatus should be used to the east and west of Berlin, in +order to distinguish general terrestrial phenomena from those which are mere +local disturbances, depending on the inequality of heat in different parts +of the Earth, or on the cloudiness of the atmosphere. My departure to +Paris, and the long period of political disturbance that involved the whole +of the west of Europe, prevented my wish from being then accomplished. +(OErsted's great discovery (1820) of the intimate connection between +electricity and magnetism again excited a general interest (which had long +flagged) in the periodical variations of the electro-magnetic tension of the +Earth. Arago, who many years previously had commenced in the Observatory at +Paris, with a new and excellent declination instrument by Gambey, the +longest uninterrupted series of horary observations which we possess in +Europe, showed by a comparison with simultaneous observations of +perturbation made at Kasan, what advantages might be obtained from +corresponding measurements of declination. When I returned to Berlin, after +an eighteen years' residence in France, I had a small magnetic house erected +in the autumn of 1828, not only with the view of carrying on the work +commenced in 1806, but more with the object that simultaneous observations +at hours previously determined might be made at Berlin, Paris, and Freiburg, +at a depth of 35 fathoms below the surface. The simultaneous occurrence of +the perturbations, and the parallelism of the movements for October and +December, 1829, were then graphically represented. (Pogg., 'Annalen', bd. +xix., s. 357, taf. i.-iii.) An expedition into Northern Asia, undertaken in +1829, by command of the Emperor of Russia, soon gave me an opportunity of +working out my plan on a larger scale. The plan was laid before a select +committee of one of the Imperial Academies of Science, and, under the +protection of the Director of the Mining Department, Count von Cancrin, and +the excellent superintendence of Professor Kupffer, magnetic stations were +appointed over the whole of Northern Asia, from Nicolajeff, in the line +through Catharinenburg, Barnaul, and Nertschinsk, to Pekin. + +[footnote continues] The year 1832 ('Gottinger gelehrte Anzeigen', st. 206) +is distinguished as the great epoch in which the profound author of a +general theory of terrestrial magnetism, Friedrich Gauss, erected apparatus, +constructed on a new principle, in the Gottingen Observatory. The magnetic +observatory was finished in 1834, and in the same year Gauss distributed new +instruments, with instructions for their use, in which the celebrated +physicist, Wilhelm Weber, took extreme interest, over a large portion of +Germany and Sweden, and the whole of Italy. ('Resultate der Beob. des +Magnetischen Verceins in Jahr' 1338, s. 135, and Poggend., 'Annalen.' bd. +xxxiii., s. 426.) In the magnetic association that was now formed with +Gottingen for its center, simultaneous observations have been undertaken +four times a year since 1836, and continued uninterruptedly for twenty-four +hours. The periods, however, do not coincide with those of the equinoxes +and solstices, which I had proposed and followed out in 1830. Up to this +period, Great Britain, in possession of the most extensive commerce and the +largest navy in the world, had taken no part in the movement which since +1828 had begun to yield important results for the more fixed ground-work of +terrestrial magnetism. I had the good fortune, by a public appeal from +Berlin which I sent in April 1836, to the Duke of Sussex, at that time +President of the Royal Society (Lettre de M. de Humboldt a S. A. R. le Duc +de Sussex, sur les moyens propres a perfectionner la connaissance du +magnetisme terrestre par l'establissement des stations magnetiques et +d'observations correspondantes), to excite a friendly interest in the +undertaking which it had so long been the chief object of my wish to carry +out. In my letter to the Duke of Sussex I urged the establishment of +permanent stations in Canada, St. Helena, the Cape of Good Hope, the Isle of +France, Ceylon, and New Holland, which five years previously I had advanced +as good positions. The Royal Society appointed a joint physical and +meteorological committee, which not only proposed to the government the +establishment of fixed magnetic observatories in both hemispheres, but also +the equipment of a naval expedition for magnetic observations in the +Antarctic Seas. It is needless to proclaim the obligations of science to +the great activity of Sir John Herschel, Sabine, Airy, and Lloyd, as well as +the powerful support that was afforded by the British Association for the +Advancement of Science at their meeting held at Newcastle in 1838. In June, +1839, the Antarctic magnetic expedition, under the command of Captain James +Clark Ross, was fully arranged; and now, since its successful return, we +reap the double fruits of the highly important geographical discoveries +around the south pole, and a series of simultaneous observations at eight or +ten magnetic stations. + + +A great English astronomer and physicist has calculated* that the mass of +observations which are in progress will accumulate in the course of three +years to 1,958,000. + + +[footnote] *See the article on 'Terrestrial Magnetism', in the 'Quarterly +Review' 1840, vol. lxvi., p. 271-312. + + +Never before has so noble and cheerful a spirit presided over the inquiry +into the 'quantitative' relations of the laws of the phenomena of nature. +We are, therefore, justified in hoping that these laws, when compared with +those which govern the atmosphere and the remoter regions of space, may, by +degrees, lead us to a more intimate acquaintance with the genetic conditions +of magnetic phenomena. As yet we can only boast of having opened a greater +number of paths which may possibly lead to an explanation of this subject. +In the physical science of terrestrial +p 193 +magnetism, which must not be confounded with the purely mathematical branch +of the study, those persons only will obtain perfect satisfaction who, as in +the science of the meteorological processes of the atmosphere conveniently +turn aside the practical bearing of all phenomena that can not be explained +according to their own views. + +Terrestrial magnetism, and the electro-dynamic forces computed by the +intellectual Ampere,* stand in simultaneous and intimate connection with the +terrestrial or polar light, as well as with the internal and external heat +of our planet, whose magnetic poles may be considered as the poles of cold.** + + +[footnote] *Instead of ascribing the internal heat of the Earth to the +transition of matter from a vapor-like fluid to a solid condition, which +accompanies the formation of the planets, Ampere has propounded the idea, +which I regard as highly improbable, that the Earth's temperature may be the +consequence of the continuous chemical action of a nucleus of the metals of +the earths and alkalies on the oxydizing external crust. "It can not be +doubted," he observes in his masterly 'Theorie des Phenomenes +Electro-dynamiques', 1826, p. 199, "that electro-magnetic currents exist in +the interior of the globe, and that these currents are the cause of its +temperature. They arise from the action of a central metallic nucleus, +composed of the metals discovered by Sir Humphrey Davy, acting on the +surrounding oxydized layer." + + +[footnote] **The remarkable connection between the curvature of the +magnetic lines and that of my isothermal lines was first detected by Sir +David Brewster. See the 'Transactions of the Royal Society of Edinburgh', +vol. ix., 1821, p. 318, and 'Treatise on Magnetism', 1837, p. 42, 44, 47, +and 268. This distinguished physicist admist two cold poles (poles of +maximum cold) in the northern hemisphere, an American one near Cape Walker +(73 degrees lat., 100 degrees W. long.), and an Asiatic one (73 degrees +lat., 80 degrees E. long.); whence arise, according to him, two hot and two +cold meridians, i.e., meridians of greatest heat and cold. Even in the +sixteenth century, Acosts ('Historia Natural de las Indias', 1589, lib. i., +cap. 17), grounding his opinion on the observations of a very experienced +Portuguese pilot, taught that there were four lines without declination. It +would seem from the controversy of Henry Bond (the author of 'The Longitude +Found', 1676) with Beckborrow, that this view in some measure influenced +Halley in his theory of four magnetic poles. See my 'Examen Critique de +l'Hist. de la Geographie', t. iii., p. 60. + + +The bold conjecture hazarded one hundred and twenty-eight years since by +Halley,* that the Aurora Borealis was a magnetic phenomenon, has acquired +empirical certainty from Faraday's brilliant discovery of the evolution of +light by magnetic forces. + + +[footnote] *Halley, in the 'Philosophical Transactions', vol. xxix. (for +1714-1716), No. 341. + + +The northern light is preceded by premonitory signs. Thus, in the morning +before the occurrence of the phenomenon, the irregular horary course of the +magnetic needle generally indicates a disturbance of the equilibrium in the +distribution of +p 194 +terrestrial magnetism.* + + +[footnote] *[The Aurora Borealis of October 24th, 1847, which was one of +the most brilliant ever known in this country, was preceded by great +magnetic disturbance. On the 22d of October the maximum of the west +declination was 23 degrees 10'; on the 23d the position of the magnet was +continually changing, and the extreme west declinations were between 22 +degrees 44' and 23 degrees 37';on the night between the 23d and 24th of +October, the changes of position were very large and very frequent, the +magnet at times moving across the field so rapidly that a difficulty was +experienced in following it. During the day of the 24th of October there +was a constant change of position, but after midnight, when the Aurora began +perceptibly to decline in brightness, the disturbance entirely ceased. The +changes of position of the horizontal-force magnet were as large and as +frequent as those of the declination magnet, but the vertical-force magnet +was at no time so much affected as the other two instruments. See 'On the +Aurora Borealis, as it was seen on Sunday evening, October 24th, 1847, at +Blackheath,' by James Glaisher, Esq., of the Royal Observatory, Greenwich, +in the 'London, Edinburgh, and Dublin Philos. Mag and Journal of Science for +Nov.', 1847, by John H. Morgan, Esq. We must not omit to mention that +magnetic disturbance is now registered by a 'photographic' process: the +self-registering photographic apparatus used for this purpose in the +Observatory at Greenwich was designed by Mr. Brooke, and another ingenious +instrument of this kind has been invented by Mr. F. Ronalds, of the Richmond +Observatory.] -- Tr. + + +When this disturbance attains a great degree of intensity, the equilibrium +of the distribution is restored by a discharge attended by a development of +light "The Aurora* itself is, therefore, not to be regarded as an externally +manifested cause of this disturbance, but rather as a result of telluric +activity, manifested on the one side by the appearance of the light, and on +the other by the vibrations of the magnetic needle." + + +[footnote] *Dove, in Poggend., 'Annalen', bd. xx., s. 341; bd. xix., s. +388. "The declination needle acts in very nearly the same way as an +atmospheric electrometer, whose divergence in like manner shows the +increased tension of the electricity before this has become so great as to +yield a spark." See also, the excellent observations of Professor Käwmtz, +in his 'Lehrbuch der Meteorologie', bd. iii., s. 511-519, and Sir David +Brewster, in his 'Treatise on Magnetism', p. 280. Regarding the magnetic +properties of the galvanic flame, or luminous arch from a Bunsen's carbon +and zinc battery, see Casselmann's 'Beobachtungen' (Marburg, 1844), s. 56-62. + + +The splendid appearance of colored polar light is the act of discharge, the +termination of a magnetic storm, as in an electrical storm a development of +light -- the flash of lightning -- indicates the restoration of the +disturbed equilibrium in the distribution of the electricity. An electric +storm is generally confined to a small space beyond the limits of which the +condition of the atmospheric electricity remains unchanged. A magnetic +storm, on the other hand, +p 193 +shows its influence on the course of the needle over large portions of +continents, and, as Arago first discovered far from the spot where the +evolution of light was visible. It is not improbable that, as +heavily-charged threatening clouds, owing to frequent transitions of the +atmospheric electricity to an opposite condition, are not always discharged, +accompanied by lightning, so likewise magnetic storms may occasion +far-extending disturbances in the horary course of the needle, without there +being any positive necessity that the equilibrium of the distribution should +be restored by explosion, or by the passage of luminous effusions from one +of the poles to the equator, or from pole to pole. + +In collecting all the individual features of the phenomenon in one general +picture, we must not omit to describe the origin and course of a perfectly +developed Aurora Borealis. Low down in the distant horizon, about the part +of the heavens which is intersected by the magnetic meridian, the sky which +was previously clear is at once overcast. A dense wall of bank of cloud +seems to rise gradually higher and higher, until it attains an elevation of +8 or 10 degrees. The color of the dark segment passes into brown or +violet; and stars are visible through the cloudy stratum, as when a dense +smoke darkens the sky. A broad, brightly-luminous arch, first white, then +yellow, encircles the dark segment; but as the brilliant arch appears +subsequently to the smoky gray segment, we can not agree with Argelander in +ascribing the latter to the effect of mere contrast with the bright luminous +margin.* + + +[footnote] *Argelander, in the important observations on the northern light +embodied in the 'Vorträgen gehalten in der physikalish-okonomischen +Gessellschaft zu Konigsberg', bd. i., 1834, s. 257-264. + + +The highest point of the arch of light is, according to accurate +observations made on the subject,* not generally in the magnetic meridian +itself, but from 5 degrees to 18 degrees toward the direction of the +magnetic declination of the place.** + + +[footnote] *For an account of the results of the observations of Lottin, +Bravais, and Siljerstrom, who spent a winter at Bosekop, on the coast of +Lapland (70 degrees N. lat.), and in 210 nights saw the northern lights 160 +times, see the 'Comptes Rendus de l'Acad. des Sciences', t. x., p. 289, and +Martins's 'Meteorologie', 1843, p. 453. See also, Argelander in the +'Vortragen geh. in der Konigsberg Gessellschaft', bd. i., s. 259. + + +[footnote] **[Professor Challis of Cambridge, states that in the Aurora of +October 24th, 1847, the streamers all converged toward a single point of the +heavens, situated in or very near a vertical circle passing through the +magnetic pole. Around this point a corona was formed, the rays of which +diverged in all directions from the center, leaving a space free from light: + its azimuth was 18 degrees 41' from south to east, and its altitude 69 +degrees 54'. See Professor Challis, in the 'Athenaeum', Oct. 31, 1847.] -- +Tr. + + +In the northern latitudes, +p 196 +in the immediate vicinity of the magnetic pole, the smoke-like conical +segment appears less dark, and sometimes is not even seen. Where the +horizontal force is the weakest, the middle of the luminous arch deviates +the most from the magnetic meridian. + +The luminous arch remains sometimes for hours together flashing and kindling +in ever-varying undulations, before rays and streamers emanate from it, and +shoot up to the zenith. The more intense the discharges of the northern +light, the more bright is the play of colors, through all the varying +gradations from violet and bluish white to green and crimson. Even in +ordinary electricity excited by friction, the sparks are only colored in +cases where the explosion is very violent after great tension. The magnetic +columns of flame rise eithr singly from the luminous arch, blended with +black rays similar to thick smoke, or simultaneously in many opposite points +of the horizon, uniting together to torm a flickering sea of flame, whose +brilliant beauty admits of no adequate description, as the luminous waves +are every moment assuming new and varying forms. The intensity of this +light is at times so great, that Lowenorn (on the 29th of June, 1786) +recognized the coruscation of the polar light n bright sunshine. Motion +renders the phenomenon more visible. Round the point in the vault of heaven +which corresponds to the direction of the inclination of the needle, the +beams unite together to form the so-called corona, the crown of the northern +light, which encircles the summit of the heavenly canopy with a milder +radiance and unflickering emanations of light. It is only in rare instances +that a perfect crown or circle is formed, but on its completion the +phenomenon has invariably reached its maximum, and the radiations become +less frequent, shorter, and more colorless. The crown and the luminous +arches break up, and the whole vault of heaven becomes covered with +irregularly-scattered, broad, faint, almost ashy-gray luminous immovable +patches, which in their turn disappear, leaving nothing but a trace of the +dark, smoke-like segment on the horizon. There often remains nothing of the +whole spectacle but a white, delicate cloud with feathery edges, or divided +at equal distances into small roundish groups like cirio-cumuli. + +This connection of the polar light with the most delicate cirrous clouds +deserves special attention, because it shows that the electro-magnetic +evolution of light is a part of a meteorological process. Terrestrial +magnetism here manifests its influence +p 197 +on the atmosphere and on the condensation of aqueous vapor. The fleecy +clouds seen in Iceland by Thienemann, and which he considered to be the +northern light, have been seen in recent times by Franklin and Richardson +near the American north pole, and by Admiral Wrangel on the Siberian coast +of the Polar Sea. All remarked "that the Aurora flashed forth in the most +vivid beams when masses of cirrous strata were hovering in the upper regions +of the air, and when these were so thin that their presence could only be +recognized by the formation of a halo round the moon." These clouds +sometimes range themselves, even by day in a similar manner to the beams of +the Aurora, and then disturb the course of the magnetic needle in the same +manner as the latter. On the morning after every distinct nocturnal Aurora, +the same superimposed strata of clouds have still been observed that had +previously been luminous.* + + +[footnote] *John Franklin, 'Narrative of a Journey to the Shores of the +Polar Sea, in the Years 1819-1822', p. 552 and 597; Thienemann in the +'Edinburgh Philosophical Journal', vol. xx., p. 336; Farquharson, in vol. +vi., p. 392, of the same journal; Wrangel, 'Phys. Beob.', s. 59. Parry even +saw the great arch of the northern light continue throughout the day. +('Journal of the Royal Institution of Great Britain', 1828, Jan., p. 429.) + + +The apparently converging polar zones (streaks of clouds in the direction of +the magnetic meridian), which constantly occupied my attention during my +journeys on the elevated plateaux of Mexico and in Northern Asia, belong +probably to the same group of ciurnal phenomena.* + + +[footnote] *On my return from my American travels, I described the delicate +cirro-cumulus cloud, which appears uniformly divided, as if by the action of +repulsive forces, under the name of polar bands ('bandes polaires'), because +their perspective point of convergence is mostly at first in the magnetic +pole, so that the parallel rows of fleecy clouds follow the magnetic +meridian. One peculiarity of this mysterious phenomenon is the oscillation, +or occasionally the gradually progressive motion, of the point of +convergence. It is usually observed that the bands are only fully developed +in one region of the heavens, and they are seen to move first from south to +north, and then gradually from east to west. I could not trace any +connection between the advancing motion of the bands and alterations of the +currents of air in the higher regions of the atmosphere. They occur when +the air is extremely calm and the heavens are quite serene, and are much +more common under the tropics than in the temperate and frigid zones. I +have seen this phenomenon on the Andes, almost under the equator, at an +elevation of 15,920 feet, and in Northern Asia, in the plains of +Krasnojarski, south of Buchtarminsk, so similarly developed, that we must +regard the influences producing it as very widely distributed, and as +depending on general natural forces. See the important observations of +Kamtz ('Vorlesungen uber Meteorologie', 1840, s. 146), and the more recent +ones of Martins and Bravais ('Meteorologie', 1843, p. 117). In south polar +bands, composed of very delicate clouds, observed by Arqago at Paris on the +23d of June, 1844, dark rays shot upward from an arch running east and west. + We have already made mention of black rays, resembling dark smoke, as +occurring in brilliant nocturnal northern lights. + + +p 198 +Southern lights have often been seen in England by the intelligent and +indefatigable observer Dalton and northern lights have been observed in the +southern hemisphere as far as 45 degrees latitude (as on the 14th of +January, 1831). On occasions that are by no means of rare occurrence, the +equilibrium at both poles has been simultaneously disturbed. I have +discovered with certainty that northern polar lights have been seen within +the tropics in Mexico and Peru. We must distinguish between the sphere of +simultaneous visibility of the phenomenon and the zones of the Earth where +it is seen almost nightly. Every observer no doubt sees a separate Aurora +of his own, as he sees a separate rainbow. A great portion of the Earth +simultaneously engenders these phenomena of emanations of light. Many +nights may be instanced in which the phenomenon has been simultaneously +observed in England and in Pennsylvania, in Rome and in Pekin. When it is +stated that Auroras diminish with the decrease of latitude, the latitude +must be understood to be magnetic, and as measured by its distance from the +magnetic pole. In Iceland, in Greenland, Newfoundland, on the shores of the +Slave Lake, and at Fort Enterprise in Northern Canada, these lights appear +almost every night at certain seasons of the year, celebrating with their +flashing beams, according to the mode of expression common to the +inhabitants of the Shetland Isles, "a merry dance in heaven."* + + +[footnote] *The northrn lights are called by the Shetland Islanders "the +merry dancers." (Kendal, in the 'Quarterly Journal of Science', new series, +vol. iv., p. 395.) + + +While the Aurora is a phenomenon of rare occurrence in Italy, it is +frequently seen in the latitude of Philadelphia (39 degrees 57'), owing to +the southern position of the American nagnetic pole. In the districts which +are remarkable, in the New Continent and the Siberian coasts, for the +frequent occurrence of this phenomenon, there are special regions or zones +of longitude in which the polar light is particularly bright and brilliant.* + + +[footnote] *See Muncke's excellent work in the new edition of Gehler's +'Physik Worterbuch', bd. vii., i., s 113-268, and especially s. 158. + + +The existence +p 199 +of local influences can not, therefore, be denied in these cases. Wrangel +saw the brilliancy diminish as he left the shores of the Polar Sea, about +Mischne-Kolymsk. The observations made in the North Polar expedition appear +to prove that in the immediate vicinity of the magnetic pole the development +of light is not in the least degree more intense or frequent than at some +distance from it. + +The knowledge which we at present possess of the altitude of the polar light +is based on measurements which from their nature, the constant oscillation +of the phenomenon of light, and the consequent uncertainty of the angle of +parallax, are not deserving of much confidence. The results obtained, +setting aside the older data, fluctuate between several miles and an +elevation of 3000 or 4000 feet; and, in all probability, the northern lights +at different times occur at very different elevations.* + + +[footnote] *Farquharson in the 'Edinburgh Philos. Journal', vol. xvi., p. +304; 'Philos. Transact.' for 1829, p. 113. +[The height of the bow of light of the Aurora seen at the Cambridge +Observatory, March 19, 1847, was determined by Professors Challis, of +Cambridge, and Chevallier, of Durham, to be 177 miles above the surface of +the Earth. See the notice of this meteor in 'An Account of the Aurora +Borealis of Oct. 24, 1847', by John H. Morgan, Esq., 1848.] -- Tr.] + + +The most recent observers are disposed to place the phenomenon in the region +of clouds, and not on the confines of the atmosphere; and they even believe +that the rays of the Aurora may be affected by winds and currents of air, if +the phenomenon of light, by which alone the existence of an electro-magnetic +current is appreciable, be actually connected with matrial groups of +vesicles of vapor in motion, or, more correctly speaking, if light penetrate +them, passing from one vesicle to another. Franklin saw near Great Bear +Lake a beaming northern light, the lower side of which he thought +illuminated a stratum of clouds, while, at a distance of only eighteen +geographical miles, Kendal, who was on watch throughout the whole night, and +never lost sight of the sky, perceived no phenomenon of light. The +assertion, so frequently maintained of late, that the rays of the Aurora +have been seen to shoot down to the ground between the spectator and some +neighboring hill, is open to the charge of optical delusion, as in the cases +of strokes of lightning or of the fall of fire-balls. + +Whether the magnetic storms, whose local character we have illustrated by +such remarkable examples, share noise as well as light in common with +electric storms, is a question +p 200 +that has become difficult to answer, since implicit confidence is no longr +yielded to the relations of Greenland whale-fishers and Siberian +fox-hunters. Northern lights appear to have become less noisy since their +occurrences have been more accurately recorded. Parry, Franklin, and +Richardson, near the north pole; Thienemann in Iceland; Gieseke in +Greenland; Lotur, and Bravais, near the North Cape; Wrangel and Anjou, on +the coast of the Polar Sea, have together seen the Aurora thousands of +times, but never heard any sound attending the phenomenon. If this negative +testimony should not be deemed equivalent to the positive counter-evidence +of Hearne on the mouth of the Copper River and of Henderson in Iceland, it +must be remembered that, although Hood heard a noise as of quickly-moved +musket-balls and a slight cracking sound during an Aurora, he also noticed +the same noise on the following day, when there was no northern light to be +seen; and it must not be forgotten that Wrangel and Gieseke were fully +convinced that the sound they had heard was to be ascribed to the +contraction of the ice and the crust of the snow on the sudden cooling of +the atmosphere. The belief in a crackling sound has arisen, not among the +people generally, but rather among learned travelers, because in earlier +times the northern light was declared to be an effect of atmospheric +electricity, on account of the luminous manifestation of the electricity in +rarefied space, and the observers found it easy to hear what they wished to +hear. Recent experiments with very sensitive electrometers have hitherto, +contrary to the expectation generally entertained, yielded only negative +results. The condition of the electricity in the atmosphere* +p 291 +is not found to be changed during the most intense Aurora; but, on the other +hand, the three expressions of the power of terrestrial magnetism, +declination, inclination and intensity, are all affected by polar light, so +that in the same night, and at different periods of the magnetic +development, the same end of the needle is both attracted and repelled. + + +[footnote] *[Mr. James Glaisher, of the Royal Observatory, Greenwich, in +his interesting 'Remarks on the Weather during the Quarter ending December +31st, 1847', says, "It is a fact well worthy of notice, that from the +beginning of this quarter till the 29th of December, the electricity of the +atmosphere was almost always in a neutral state, so that no signs of +electricity were shown for several days together by any of the electrical +instruments." During this period there were 'eight' exhibitions of the +Aurora Borealis, of which one was the peculiarly bright display of the +Aurora Borealis, of which one was the peculiarly bright display of the +meteor on the 24th of October. These frequent exhibitions of brilliant +Aurorae seem to depend upon many remarkable meteorological relations, for we +find, according to Mr. Glaisher's statement in the paper to which we have +already alluded, that the previous fifty years afford no parallel season to +the closing one of 1847. The mean temperature of evaporation and of the dew +point, the mean elastic force of vapor, the mean reading of the barometer, +and the mean daily range of the readings of the thermometers in air, were +all greater at Greenwich during that season of 1847 than the average range +of many preceding years.] -- Tr. + + +The assertion made by Parry, on the strength of the data yielded by his +observations in the neighborhood of the magnetic pole at Melville Island, +that the Aurora did not disturb, but rather exercised a calming influence on +the magnetic needle, has been satisfactorily refuted by Parry's own more +exact researches,* detailed in his journal, and by the admirable +observations of Richardson, Hood, and Franklin in Northern Canada, and +lastly by Bravais and Lottin in Lapland. + + +[footnote] *Kamtz, 'Lehrbuch der Meteorologie', bd. iii., s. 498 and 501. + + +The process of the Aurora is, as has already been observed, the restoration +of a disturbed condition of equilibrium. The effect on the needle is +different according to the degree of intensity of the explosion. It was +only unappreciable at the gloomy winter station of Bosekop when the +phenomenon of light was very faint and aptly compared to the flame which +rises in the closed circuit of a voltaic pile between two points of carbon +at a considerable distance apart, or, according to Fizeau, to the flame +rising between a silver and a carbon point, and attracted or repelled by the +magnet. This analogy certainly sets aside the necessity of assuming the +existence of metallic vapors in the atmosphere, which some celebrated +physicists have regarded as the substratum of the northern light. + +When we apply the indefinite term 'polar light' to the luminous phenomenon +which we ascribe to a galvanic current, that is to say, to the motion of +electricity in a closed circuit, we merely indicate the local direction in +which the evolution of light is most frequently, although by no means +invariably, seen. This phenomenon derives the greater part of its +importance from the fact that the Earth becomes 'self-luminous', and that as +a planet, besides the light which it receives from the central body, the +Sun, it shows itself capable in itself of developing light. The intensity +of the terrestrial light, or, rather the luminosity which is diffused, +exceeds, in cases of the brightest colored radiation toward the zenith, the +light of the Moon in its first quarter. Occasionally, as on the 7th of +January, 1831, printed characters could be read without difficulty. This +almost uninterrupted development of light +p 202 +in the Earth leads us by analogy to the remarkable process exhibited in +Venus. The portion of this planet which is not illumined by the Sun often +shines with a phosphorescent light of its own. It is not improbable that +the Moon, Jupiter, and the comets shine with an independent light, besides +the reflected solar light visible through the polariscope. Without speaking +of the problematical but yet ordinary mode in which the sky is illuminated, +when a low cloud may be seen to shine with an uninterrupted flickering light +for many minutes together, we still meet with other instances of terrestrial +development of light in our atmosphere. In this category we may reckon the +celebrated luminous mists seen in 1783 and 1831; the steady luminous +appearance exhibited without any flickeriing in great clouds observed by +Rozier and Beccaria; and lastly, as Arago* well remarks, the faint diffused +light which guides the steps of the traveler in cloudy, starless, and +moonless nights in autumn and winter, even when there is no snow on the +ground. + + +[footnote] *Arago, on the dry fogs of 1783 and 1831, which illuminated the +night, in the 'Annuaire du Bureau des Longitudes', 1832, p. 246 and 250; +and, regarding extraordinary luminous appearances in clouds without storms, +see 'Notices sur la Tonnerre', in the 'Annuaire pour l'an. 1838', p. 279-285. + + +As in polar light or the electro-magnetic storm, a current of brilliant and +often colored light streams through the atmosphere in high latitudes, so +also in the torrid zones between the tropics, the ocean simultaneously +develops light over a space of many thousand square miles. Here the magical +effect of light is owing to the forces of organic nature. Foaming with +light, the eddying waves flash in phosphorescent sparks over the wide +expanse of waters, where every scintillation is the vital manifestation of +an invisible animal world. So varied are the sources of terrestrial light! +Must we still suppose this light to be latent, and combined in vapors, in +order to explain 'Moser's images produced at a distance' -- a discovery in +which reality has hitherto manifested itself like a mere phantom of the +imagination. + +As the internal heat of our planet is connected on the one hand with the +generation of electro-magnetic currents and the process of terrestrial light +(a consequence of the magnetic storm), it, on the other hand, discloses to +us the chief source of geognostic phenomena. We shall consider these in +their connection with and their transition from merely dynamic disturbances, +from the elevation of whole continents and mountain chains to the +development and effusion of gaseous and +p 203 +liquid fluids, of hot mud, and of those heated and molten earths which +become solidified into crystalline mineral masses. Modern geognosy, the +mineral portion of terrestrial physics, has made no slight advance in having +investigated this connection of phenomena. This investigation has led us +away from the delusive hypothesis, by which it was customary formerly to +endeavor to explain, individually every expression of force in the +terrestrial globe: it shows us the connection of the occurrence of +heterogeneous substances with that which only appertains to changes in space +(disturbances or elevations), and groups together phenomena which at first +sight appeared most heterogeneous, as thermal springs, effusion of carbonic +acid and sulphurous vapor, innocuous salses (mud eruptions), and the +dreadful devastation of volcanic mountains.* + + +[footnote] *[See Mantell's 'Wonders of Geology', 1848, vol. i., p. 34, 36, +105; also Lyell's 'Principles of Geology', vol. ii., and Daubeney 'On +Volcanoes', 2d ed., 1848, Part ii., ch. xxxii., xxxiii.] -- Tr. + + +In a general view of nature, all these phenomena are fused together in one +sole idea of the reaction of the interior of a planet on its external +surface. We thus recognize in the depths of the earth, and in the increase +of temperature with the increase of depth from the surface, not only the +germ of disturbing movements, but also of the gradual elevation of whole +continents (as mountain chains on long fissures), of volcanic eruptions, and +of the manifold production of mountains and mineral masses. The influence +of this reaction of the interior on the exterior is not, however, limited to +inorganic nature alone. It is highly probable that, in an earlier world, +more powerful emanations of carbonic acid gas, blended with the atmosphere, +must have increased the assimilation of carbon in vegetables, and that an +inexhaustible supply of combustible matter (lignites and carboniferous +formations) must have been thus buried in the upper strata of the earth by +the revolutions attending the destruction of vast tracts of forest. We +likewise perceive that the destiny of mankind is in part dependent on the +formation of the external surface of the earth, the direction of mountain +tracts and high lands, and on the distribution of elevated continents. It +is thus granted to the inquiring mind to pass from link to link along the +chain of phenomena until it reaches the period when, in the solidifying +process of our planet, and in its first transition from the gaseous form to +the agglomeration of matter, that portion of the inner heat of the Earth was +developed, which does not belong to the action of the Sun. + +This material taken from pages 204-248 + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p 204 +In order to give a general delineation of the causal connection of +geognostical phenomena, we will begin with those whose chief characteristic +is dynamic, consisting in motion and in change in space. Earthquakes +manifest themselves by quick and successive vertical, or horizontal, or +rotatory vibrations.* + + +[footnote] *[See Daubeney 'On Volcanoes', 2d ed., 1848, p. 509.] -- Tr. + + +In the very considerable number of earthquakes which I have experienced in +both hemispheres, alike on land and at sea, the two first-named kinds of +motion have often appeared to me to occur simultaneously. The mine-like +explosiion -- the vertical action from below upward -- was most strikingly +manifested in the overthrow of the town of Riobamba in 1797, when the bodies +of many of the inhabitants were found to have been hurled to Cullea, a hill +several hundred feet in neight, and on the opposite side of the River Lican. + The propagation is most generally effected by undulations in a linear +direction,* with a velocity of from twenty to twenty-eight miles in a +minute, but partly in circles of commotion or large ellipses, in which the +vibrations are propagated with decreasing intensity from a center toward the +circumference. + + +[footnote] *[On the linear direction of earthquakes, see Daubeney 'On +Volcanoes', p. 515.] -- Tr. + + +There are districts exposed to the action of two intersecting circles of +commotion. In Northern Asia, where the Father of History,* and subsequently +Theophylactus Simocatta,** described the districts of Scythia as free from +earthquakes, I have observed the metalliferous portion of the Altai +Mountains under the influence of a two-fold focus of commotion, the Lake of +Baikal, and the volcano of the Celestial Mountain (Thianschan).*** + + +[footnote] *Herod, iv., 28. The prostration of the colossal statue of +Memnon, which has been again restored (Letronne, 'La Statue Vocale de +Memnon', 1835, p. 25, 26), presents a fact in opposition to the ancient +prejudice that Egypt is free from earthquakes (Pliny, ii., 80); but the +valley of the Nile does lie external to the circle of commotion of +Byzantium, the Archipelago, and Syria (Ideler ad Aristot., 'Meteor.', p. +584). + + +[footnote] **Saint-Martin, in the learned notes to Lebeau, 'Hist. du Bas +Empire', t. ix., p. 401. + + +[footnote] ***Humboldt, 'Asie Centrale', t. ii., p. 110-118. In regard to +the difference between agitation of the surface and of the strata lying +beneath it, see Gay-Lussac, in the 'Annales de Chimie et de Physique', t. +xxii., p. 429. + + +When the circles of commotion intersect one another -- when, for instance, +an elevated plain lies between two volcanoes simultaneously in a state of +eruption, several wave-systems may exist together, as in fluids, and not +mutually disturb one another. We may even suppose 'interference' +p 205 +to exist here, as in the intersecting waves of sound. The extent of the +propagated waves of commotion will be increased on the upper surface of the +earth, according to the general law of mechanics, by which, on the +transmission of motion in elastic bodies, the stratum lying free on the one +side endeavors to separate itself from the other strata. + +Waves of commotion have been investigated by means of the pendulum and the +seismometer* with tolerable accuracy in respect to their direction and total +intensity, but by no means with reference to the internal nature of their +alternations and their periodic intumescence. + + +[footnote] *[This instrument, in its simplest form, consists merely of a +basin filled with some viscid liquid, which, on the occurrence of a shock of +an earthquake of sufficient force to disturb the equilibrium of the building +in which it is placed, is tilted on one side, and the liquid made to rise in +the same direction, thus showing by its height the degree of the +disturbance. Professor J. Forbes has invented an instrument of this nature, +although on a greatly improved plan. It consists of a vertical metal rod, +having a ball of lead movable upon it. It is supported upon a cylindrical +steel wire, which may be compressed at pleasure by means of a screw. A +lateral movement, such as that of an earthquake, which carries forward the +base of the instrument, can only act upon the ball through the medium of the +elasticity of the wire, and the direction of the displacement will be +indicated by the plane of vibration of the pendulum. A self-registering +apparatus is attached to the machine. See Professor J. Forbes's account of +his invention in 'Edinb. Phil. Trans.', vol. xv., Part i.] -- Tr. + + +In the city of Quito, which lies at the foot of a still active volcano (the +Rucu Pichincha), and at an elevation of 9540 feet above the level of the +sea, which has beautiful cupolas, high vaulted churches, and massive +edifices of several stories, I have often been astonished that the violence +of the nocturnal earthquakes so seldom causes fissures in the walls, while +in the Peruvian plains oscillations apparently much less intense injure low +reed cottages. The natives, who have experienced many hundred earthquakes, +believe that the difference depends less upon the length or shortness of the +waves, and the slowness or rapidity of the horizontal vibrations.* than on +the uniformity of the motion in opposite directions. + + +[footnote] * "Tutissimum est cum vibrat crispante Aedificiorum crepitu; et +cum intumescit assurgens alternoque motu residet, innoxium et cum +concurrentia tecta contrario ictu arietant; quoniam alter motus alteri +renititur. Undantis inclinatio et fluctus more quaedam volutatio investa +est, aut cum in unam partem totus se motus impellitae -- Plin., ii., 82. + + +The circling rotatory commotions are the most uncommon, but, at the same +time, the most dangerous. Walls were observed to be twisted, but not thrown +down; rows of trees turned from their previous parallel direction; +p 206 +and fields covered with different kinds of plants found to be displaced in +the great earthquake of Riobamba, in the province of Quito, on the 4th of +February, 1797, and in that of Calabria, between the 5th of February and the +28th of March, 1782. The phenomenon of the inversion or displacement of +fields and pieces of land, by which one is made to occupy the place of +another, is connected with a translatory motion or penetration of separate +terrestrial strata. When I made the plan of the ruined town of Riobamba, +one particular spot was pointed out to me, where all the furniture of one +house had been found under the ruins of another. The loose earth had +evidently moved like a fluid in currents, which must be assumed to have been +directed first downward, then horizontally, and lastly upward. It was found +necessary to appeal to the 'Audiencia', or Council of Justice, to decide +upon the contentions that arose regarding the proprietorship of objects that +had been removed to a distance of many hundred roises. + +In countries where earthquakes are comparatively of much less frequent +occurrence (as for instance, in Southern Europe), a very general belief +prevails, although unsupported by the authority of inductive reasoning,* +that a calm, an oppressive +p 207 +heat and a misty horizon, are always the forerunners of this phenomenon. + + +[footnote] *Even in Italy they have begun to observe that earthquakes are +unconnected with the state of the weather, that is to say, with the +appearance of the heavens immediately before the shock. The numerical +results of Friedrich Hoffmann ('Hinterlassene Werke', bd. ii., 366-376) +exactly correspond with the experience of the Abbate Scina of Palermo. I +have myself several times observed reddish clouds on the day of an +earthquake, and shortly before it on the 4th of November, 1799, I +experienced two sharp shocks at the moment of a loud clap of thunder. +('Relat. Hist.', liv. iv., chap. 10.) The Turin physicist, Vassalli Eaudi, +observed Volta's electrometer to be strongly agitated during the protracted +earthquake of Pignerol, which lasted from the 2d of April to the 17th of +May, 1808; 'Journal de Physique', t. lxvii., p. 291. But these indications +presented by clouds, by modifications of atmospheric electricity, or by +calms, can not be regarded as 'generally' or 'necessarily' connected with +earthquakes, since in Quito, Peru, and Chili, as well as in Canada and +Italy, many earthquakes are observed along with the purest and clearest +skies, and with the freshest land and sea breezes. But if no meteorological +phenomenon indicates the coming earthquake either on the morning of the +shock or a few days previously, the influence of certain periods of the year +(the vernal and autumnal equinoxes), the commencement of the rainy season in +the tropics after long drought, and the change of the monsoons (according to +general belief), can not be overlooked, even though the genetic connection +of meteorological processes with those going on in the interior of our globe +is still enveloped in obscurity. Numerical inquiries on the distribution of +earthquakes throughout the course of the year, such as those of Von Hoff, +Peter Merian, and Friedrich Hoffmann, bear testimony to their frequency at +the periods of equinoxes. It is singular that Pliny, at the end of his +fanciful theory of earthquakes, names the entire frightful phenomenon a +subterranean storm; not so much in consequence of the rolling sound which +frequently accompanies the shock, as because the elastic forces, concussive +by their tension, accumulate in the interior of the earth when they are +absent in the atmosphere! "Ventos in causa esse non dubium reor. Neque +enim unquam intemiscunt terre, nisi sopito mari, coeloque adeo tranquillo, +ut volatus avium non pendeant, subtracto omni spiritu qui vehit; nec unquam +nisi post ventos conditos, scilicet in venas et cavernas ejus occulto +afflatu. Neque aliad est in terra tremor, quam in nube toonitruum; nec +hiatus aliud quam cum fulmen erumpit, incluso spiritu luctante et ad +libertatem exire nitente." (Plin., ii., 79.) The germs of almost every +thing that has been observed of imagined on the causes of earthquakes, up to +the present day, may be found in Seneca, 'Nat. Quaest.', vi., 4-31. + + +The fallacy of this popular opinion is not only refuted by my own +experience, but likewise by the observations of all those who have lived +many years in districts where, as in Cumana, Quito, Peru, and Chili, the +earth is frequently and violently agitated. I have felt earthquakes in +clear air and a fresh east wind, as well as in rain and thunder storms. The +regularity of the horary changes in the declination of the magnetic needle +and in the atmospheric pressure remained undisturbed between the tropics on +the days when earthquakes occurred.* + + +[footnote] *I have given proof that the course of the horary variations of +the barometer is not affected before or after earthquakes, in my 'Relat. +Hist.', t. i., p. 311 and 513. + + +These facts agree with the observations made by Adolph Erman (in the +temperate zone, on the 8th of March, 1829) on the occasion of an earthquake +at Irkutsk, near the Lake of Baikal. During the violent earthquake of +Cumana, on the 4th of November, 1799, I found the declination and the +intensity of the magnetic force alike unchanged, but, to my surprise, the +inclination of the needle was diminished about 48 degrees.* + + +[footnonte] *Humboldt, 'Relat. Hist.', t. i., p. 515-517. + + +There was no ground to suspect an error in the calculation, and yet, in the +many other earthquakes which I have experienced on the elevated plateaux of +Quito and Lima, the inclination as well as the other elements of terrestrial +magnetism remained always unchanged. Although, in general, the processes at +work within the interior of the earth may not be announced by any +meteorological phenomena or any special appearance of the sky, it is, on the +contrary, not improbable, as we shall soon see, that in cases of violent +earthquakes some effect may be imparted to the atmosphere, in consequence of +which they can not always act in a purely dynamic manner. + +p 208 +During the long-continued trembling of the ground in the Piedmontese valleys +of Pelis and Clusson, the greatest changes in the electric tension of the +atmosphere were observed while the sky was cloudless. The intensity of the +hollow noise which generally accompanies an earthquake does not increase in +the same degree as the force of the oscillations. I have ascertained with +certainty that the great shock of the earthquake of Riobamba (4th Feb., +1797) -- one of the most fearful phenomena recorded in the physical history +of our planet -- was not accompanied by any noise whatever. The tremendous +noise ('el gram ruido') which was heard below the soil of the cities of +Quito and Ibarra, but not at Tacunga and Hambato, nearer the center of the +motion, occurred between eighteen and twenty minutes 'after' the actual +catastrophe. In the celebrated earthquake of Lima and Callao (28th of +October, 1746), a noise resembling a subterranean thunder-clap was heard at +Truxillo a quarter of an hour after the shock, and unaccompanied by any +trembling of the ground. In like manner, long after the great earthquake in +New Granada, on the 16th of November, 1827, described by Boussingault, +subterranean detonations were heard in the whole valley of Cauca during +twenty or thirty seconds, unattended by motion. The nature of the noise +varies also very much, being either rolling, or rustling, or clanking like +chains when moved, or like near thunder, as, for instance, in the city of +Quito; or, lastly, clear and ringing, as if obsidian or some other vitrified +masses were struck in subterranean cavities. As solid bodies are excellent +conductors of sound, which is propagated in burned clay, for instance, ten +or twelve times quicker than in the air, the subterranean noise may be heard +at a great distance from the place where it has originated. In Caracas, in +the grassy plains of Calabozo, and on the banks of the Rio Apure, which +falls into the Orinoco, a tremendously loud noise, resembling thunder, was +heard, unaccompanied by an earthquake, over a district of land 9200 square +miles in extent, on the 30th of April, 1812, while at a distance of 632 +miles to the north-east, the volcano of St. Vincent, in the small Antilles, +poured forth a copious stream of lava. With respect to distance, this was +as if an eruption of Vesuvius had been heard in the north of France. In the +year 1744, on the great eruption of the volcano of Cotopaxi, subterranean +noises, resembling the discharge of cannon, were heard in Honda, on the +Magdalena River. The crater of Cotopaxi lies not only 18,000 feet higher +than Honda, but these two points are separated by the colossal +p 209 +mountain chain of Quito, Pasto, and Popayan, no less than by numerous +valleys and clefts, and they are 436 miles apart. The sound was certainly +not propagated through the air, but through the earth, and at a great depth. + During the violent earthquake of New Granada, in February, 1835, +subterranean thunder was heard simultaneously at Popayan, Bogota, Santa +Marta, and Caracas (where it continued for seven hours without any movement +of the ground), in Haiti, Jamaica, and on the Lake of Nicaragua. + +These phenomena of sound, when unattended by any perceptible shocks, produce +a peculiarly deep impression even on persons who have lived in countries +where the earth has been frequently exposed to shocks. A striking and +unparalleled instance of uninterrupted subterranean noise, unaccompanied by +any trace of an earthquake, is the phenomenon known in the Mexican elevated +plateaux by the name of the "roaring and the subterranean thunder) +('bramidos y truenos subterraneos') of Guanaxuato.* + + +[footnote] *On the 'bramidos' of Guanaxuato, see my 'Essai Polit. sur la +Nouv. Espagne', t. i., p. 303. The subterranean noise, unaccompanied with +any appreciable shock, in the deep mines and on the surface (the town of +Guanaxuata lies 6830 feet above the level of the sea), was not heard in the +neighboring elevated plains, but only in the mountainous parts of the +Sierra, from the Cuesta de los Aguilares, near Marfil, to the north of Santa +Rosa. There were individual parts of the Sierra 24-28 miles northwest of +Guanaxuata, to the other side of Chichimequillo, near the boiling spring of +San Jose de Comgngillas, to which the waves of sound did not extend. +Extremely stringent measures were adopted by the magistrates of the large +mountain towns on the 14th of January 1784, when the terror produced by +these subterranean thunders was at its height. "The flight of a wealthy +family shall be punished with a fine of 1000 piasters, and that of a poor +family with two months' imprisonment. The militia shall bring back the +fugitives." One of the most remarkable points about the whole affair is the +opinion which the magistrates (el cabildo) cherished of their own superior +knowledge. In one of their 'proclamas', I find the expression, "The +magistrates, in their wisdom (en su sabiduria), will at once know when there +is actual danger, and will give orders for flight; for the present, let +processions be instituted." The terror excited by the tremor gave rise to a +famine, since it prevented the importation of corn from the table-lands, +where it abounded. The ancients were also aware that noises sometimes +existed without earthquakes. -- Aristot., 'Meteor.', ii., p. 802; Plin., +ii., 80. The singular noise that was heard from March, 1822, to September, +1824, in the Dalmatian island Meleda (sixteen miles from Ragusa) and on +which Partsch has thrown much light, was occasionally accompanied by shocks. + + +This celebrated and rich mountain city lies far removed from any active +volcano. The noise began about midnight on the 9th of January, 1784, and +continued for a month. I have been enabled to give a circumstantial +p 210 +description of it from the report of many witnesses, and from the documents +of the municipality, of which I was allowed to make use. From the 13th to +the 16th of January, it seemed to the inhabitants as if heavy clouds lay +beneath their feet, from which issued alternate slow rolliing sounds and +short, quick claps of thunder. The noise abated as gradually as it had +begun. It was limited to a small space, and was not heard in a basaltic +district at the distance of a few miles. Almost all the inhabitants, in +terror, left the city, in which large masses of silver ingots were stored; +but the most courageous, and those more accustomed to subterranean thunder, +soon returned, in order to drive off the bands of robbers who had attempted +to possess themselves of the treasures of the city. Neither on the surface +of the earth, nor in mines 1600 feet in depth, was the slightest shock to be +perceived. No similar noise had ever before been heard on the elevated +tableland of Mexico, nor has this terrific phenomenon since occurred there. +Thus clefts are opened or closed in the interior of the earth, by which +waves of sound penetrate to us or are impeded in their propagation. + +The activity of an igneous mountain, however terrific and picturesque the +spectacle may be which it presents to our contemplation, is always limited +to a very small space. It is far otherwise with earthquakes, which although +scarcely perceptible to the eye, nevertheless simultaneously propagate their +waves to a distance of many thousand miles. The great earthquake which +destroyed the city of Lisbon on the 1st of November, 1755, and whose effects +were so admirably investigated by the distinguished philosopher Emmanuel +Kant, was felt in the Alps, on the coast of Sweden, in the Antilles, +Antigua, Barbadoes, and Martinique; in the great Canadian Lakes, in +Thuringia, in the flat country of Northern Germany, and in the small inland +lakes on the shores of the Baltic.* + + +[footnote] *[It has been computed that the shock of this earthquake +pervaded an area of 700,000 miles, or the twelfth part of the circumference +of the globe. This dreadful shock lasted only five minutes: it happened +about nine o'clock in the morning of the Feast of all Saints, whien almost +the whole population was within the churches, owing to which circumstance no +less than 30,000 persons perished by the fall of these edifices. See +Daubeney 'On Volcanoes', p. 514-517.] -- Tr. + + +Remote springs were interrupted in their flow, a phenomenon attending +earthquakes which had been noticed among the ancients by Demetrius the +Callatian. The hot springs of Toplitz dried up, and returned, inundating +every thing around, and having their waters colored with iron ocher. In +Cadiz +p 211 +the sea rose to an elevation of sixty-four feet, while in the Antilles, +where the tide usually rises only from twenty-six to twenty-eight inches, it +suddenly rose above twenty feet, the water being of an inky blackness. It +has been computed that on the 1st of November, 1755, a portion of the +Earth's surface four times greater than that of Europe, was simultaneously +shaken. As yet there is no manifestation of force known to us, including +even the murderous inventions of our own race, by which a greater number of +people have been killed in the short space of a few minutes: sixty thousand +were destroyed in Sicily in 1693, from thirty to forty thousand in the +earthquake of Riobamba in 1797, and probably five times as many in Asia +Minor and Syria, under Tiberius and Justinian the elder, about the years 19 +and 526. + +There are instances in which the earth has been shaken for many successive +days in the chain of the Andes in South America, but I am only acquainted +with the following cases in which shocks that have been felt almost every +hour for months together have occurred far from any volcano, as, for +instance, on the eastern declivity of the Alpine chain of Mount Cenis, at +Fenestrelles and Pignerol, from April, 1808; between New Madrid and Little +Prairie,* north of Cincinnati in the United States of America, in December, +1811, as well as through the whole winter of 1812; and in the Pachalik of +Aleppo, in the months of August and September, 1822. + + +[footnote] *Drake, 'Nat. and Statist. View of Cincinnati', p. 232-238; +Mitchell, in the 'Transactions of the Lit. and Philos. Soc. of New York', +vol. i., p. 281-308. In the Piedmonese county of Pignerol, glasses of +water, filled to the very brim, exhibited for hours a continuous motion. + + +As the mass of the people are seldom able to rise to general views, and are +consequently always disposed to ascribe great phenomena to local telluric +and atmospheric processes, wherever the shaking of the earth is continued +for a long time, fears of the eruption of a new volcano are awakened. In +some few cases, this apprehension has certainly proved to be well grounded, +as, for instance, in the sudden elevation of volcanic islands, and as we see +in the elevation of the volcano of Jorullo, a mountain elevated 1684 feet +above the ancient level of the neighboring plain, on the 29th of September +1759, after ninety days of earthquake and subterranean thunder. + +If we could obtain information regarding the daily condition of all the +earth's surface, we should probably discover that the earth is almost always +undergoing shocks at some point of its superficies, and is continually +influenced by the reaction +p 212 +of the interior on the exterior. The frequency and general prevalence of a +phenomenon which is probably dependent on the raised temperature of the +deepest molten strata explain its independence of the nature of the mineral +masses in which it manifests itself. Earthquakes have even been felt in the +loose alluvial strata of Holland, as in the neighborhood of Middleburg and +vliessingen on the 23d of February, 1828. Granite and mica slate are shaken +as well as limestone and sandstone, or as trachyte and amygdaloid. It is +not, therefore, the chemical nature of the constituents, but rather the +mechanical structure of the rocks, which modifies the propagation of the +motion, the wave of commotion. Where this wave proceeds along a coast, or +at the foot and in the direction of a mountain chain, interruptions at +certain points have sometimes been remarked, which manifested themselves +during the course of many centuries. The undulation advances in the depths +below, but is never felt at the same points on the surface. The Peruvians* +say of these unmoved upper strata that "they form a bridge." + + +[footnote] *In Spanish they say, 'rocas que hacen puente'. With this +phenomenon of non-propagation through superior strata is connected the +remarkable fact that in the beginning of this century shocks were felt in +the deep silver mines at Marienberg, in the Saxony mining district, while +not the slightest trace was perceptible at the surface. The miners ascended +in a state of alarm. Conversely, the workmen in the mines of Falun and +Persberg felt nothing of the shocks which in November, 1823, spread dismay +among the inhabitants above ground. + + +As the mountain chains appear to be raised on fissures, the walls of the +cavities may perhaps favor the direction of undulations parallel to them; +occasionally, however, the waves of commotion intersect several chains +almost perpenducularly. Thus we see them simultaneously breaking through +the littoral chain of Venezuela and the Sierra Parime. In Asia, shocks of +earthquakes have been propagated from Lahore and from the foot of the +Himalaya (22d of January, 1832) transversely across the chain of the Hindoo +Chou to Badakschan, the upper Oxus, and even to Bokhara.* + + +[footnote] *Sir Alex. Burnes, 'Travels in Bokhara', vol. i., p. 18; and +Wathen, 'Mem. on the Usbek State', in the 'Journal of the Asiatic Society of +Bengal', vol. iii., p. 337. + + +The circles of commotion unfortunately expand occasionally in consequence of +a single and usually violent earthquake. It is only since the destruction +of Cumana, on the 14th of December, 1797, that shocks on the southern coast +have been felt in the mica slate rocks of the peninsula of Maniquarez, +situated opposite to the chalk hills of the main land. The advance +p 213 +from south to north was very striking in the almost uninterrupted +undulations of the soil in the alluvial valleys of the Mississippi, the +Arkansas, and the Ohio, from 1811 to 1813. It seemed here as if +subterranean obstacles were gradually overcome, and that the way being once +opened, the undulatory movement could be freely propagated. + +Although earthquakes appear at first sight to be simply dynamic phenomena of +motion, we yet discover, from well-attested facts, that they are not only +able to elevate a whole district above its ancient level (as for instance, +the Ulla Bund, Delta of the Indus, or the coast of Chili, in November, +1822), but we also find that various substances have been ejected during the +earthquake, as hot water at Catania in 1818; hot steam at New Madrid, in the +Valley of the Mississippi, in 1812; irrespirable gases, 'Mofettes', which +injured the flocks grazing in the chain of the Andes; mud, black smoke, and +even flames, at Messina in 1781, and at Cumana on the 14th of November, +1797. During the great earthquake of Lisbon, on the 1st of November, 1755, +flames and columns of smoke were seen to rise from a newly-formed fissure in +the rock of Alvidras, near the city. The smoke in this case became more +dense as the subterranean noise increased in intensity.* + + +[footnote] * 'Philos. Transaci.', vol. xlix. p. 414. + + +At the destruction of Riobamba, in the year 1797, when the shocks were not +attended by any outbreak of the neighboring volcano, a singular mass called +the 'Moya' was uplifted from the earth in numerous continuous conical +elevations, the whole being composed of carbon, crystals of augite, and the +silicious shields of infusoria. The eruption of carbonic acid gas from +fissures in the Valley of the Magdalene, during the earthquake of New +Granada, on the 16th of November, 1827, suffocated many snakes, rats, and +other animals. Sudden changes of weather, as the occurrence of the rainy +season in the tropics, at an unusual period of the year, have sometimes +succeeded violent earthquakes in Quito and Peru. Do gaseous fluids rise +from the interior of the earth, and mix with the atmosphere? or are these +meteorological processes the action of atmospheric electricity disturbed by +the earthquake? In the tropical regions of America, where sometimes not a +drop of rain falls for ten months together, the natives consider the +repeated shocks of earthquakes, which do not endanger the low reed huts, as +auspicious harbingers of fruitfulness and abundant rain. + +p 214 +The intimate connection of the phenomena which we have considered is still +hidden in obscurity. Elastic fluids are doublessly the cause of the slight +and perfectly harmless trembling of the earth's surface, which has often +continued several days (as in 1816, at Scaccia, in Sicily, before the +volcanic elevation of the island of Julia), as well as of the terrific +explosions accompanied by loud noise. The focus of this destructive agent, +the seat of the moving force, lies far below the earth's surface; but we +know as little of the extent of this depth as we know of the chemical nature +of these vapors that are so highly compressed. At the edges of two craters, +Vesuvius, and the towering rock which projects beyond the great abyss of +Pichincha, near Quito, I have felt periodic and very regular shocks of +earthquakes, on each occasion from 20 to 30 seconds before the burning +scoriae or gases were erupted. The intensity of the shocks was increased in +proportion to the time intervening between them, and, consequently, to the +length of time in which the vapors were accumulating. This simple fact, +which has been attested by the evidence of so many travelers, furnishes us +with a general solution of the phenomenon, in showing that active volcanoes +are to be considered as safety-valves for the immediate neighborhood. The +danger of earthquakes increases when the openings of the volcano are closed, +and deprived of free communication with the atmosphere; but the destruction +of Lisbon, of Caraccas, of Lima, of Cashmir in 1554,* and of so many cities +of Calabria, Syria, and Asia Minor, shows us, on the whole, that the force +of the shock is not the greatest in the neighborhood of active volcanoes. + + +[footnote] *On the frequency of earthquakes in Cashmir, see Troyer's German +translation of the ancient 'Radjataringini', vol. ii., p. 297, and Carl +Hugel, 'Reisen', bd. ii., s. 184. + + +As the impeded activity of the volcano acts upon the shocks of the earth's +surface, so do the latter react on the volcanic phenomena. Openings of +fissures favor the rising of cones of eruption, and the processes which take +place in these cones, by forming a free communication with the atmosphere. +A column of smoke, which had been observed to rise for months together from +the volcano of Pasto, in South America, suddenly disappeared, when on the +4th of February, 1797, the province of Quito, situated at a distance of 192 +miles to the south, suffered from the great earthquake of Riobamba. After +the earth had continued to tremble for some time through out the whole of +Syria, in the Cyclades, and in Euboea, the shocks suddenly ceased on the +eruption of a stream of hot mud +p 215 +on the Lelantine plains near Chalcia.* + + +[footnote] * Strabo, lib. i., p. 100, Casaub. That the expression [Greek +words] does not mean erupted mud, but lava, is obvious from a passage in +Strabo, lib. vi., p. 412. Compare Walter, in his 'Abnahme der Vulkanischen +Thatigkeit in Historischen Zeiten' (On the Decrease of Volcanic Activity +during Historical Times), 1844, s. 25. + + +The intelligent geographer of Amasea, to whom we are indebted for the notice +of this circumstance, further remarks: "Since the craters of Aetna have +been opened, which yield a passage to the escape of fire, and since burning +masses and water have been ejected, the country near the sea-shore has not +been so much shaken as at the time previous to the separation of Sicily from +Lower Italy, when all communications with the external surface were closed." + +We thus recognize in earthquakes the existence of a volcanic force, which, +although every where manifested, and as generally diffused as the internal +heat of our planet, attains but rarely, and then only at separate points, +sufficient intensity to exhibit the phenomenon of eruptions. The formation +of veins, that is to say, the filling up of fissures with crystalline masses +bursting forth from the interior (as basalt, melaphyre, and greenstone), +gradually disturbs the free intercommunication of elastic vapors. This +tension acts in three different ways, either in causing disruptions, or +sudden and retroversed elevations, or, finally, as was first observed in a +great part of Sweden, in producing changes in the relative level of the sea +and land, which, although continuous, are only appreciable at intervals of +long period. + +Before we leave the important phenomena which we have considered not so much +in their individual characteristics as in their general physical and +geognostical relations, I would advert to the deep and peculiar impression +left on the mind by the first earthquake which we experience, eeven where it +is not attended by any subterranean noise.* + + +[footnote] *[Dr. Tschudi, in his interesting work, 'Travels in Peru', +translated from the German by Thomasina Ross, p. 170, 1847, describes +strikingly the effect of an earthquake upon the native and upon the +stranger. "No familiarity with the phenomenon can blunt this feeling. The +inhabitant of Lima, who from childhood has frequently witnessed these +convulsions of nature, is roused from his sleep by the shock, and rushes +from his apartment with the cry of 'Misericordia!' The foreigner from the +north of Europe, who knows nothing of earthquakes but by description, waits +with impatience to feel the movement of the earth, and longs to hear with +his own ear the subterranean sounds which he has hitherto considered +fabulous. With levity he treats the apprehension of a coming convulsion, +and laughs at the fears of the natives: but, as soon as his wish is +gratified, he is terror-stricken, and is involuntarily prompted to seek +safety in flight."] -- Tr. + + +This impression is not, +p 216 +in my opinion, the result of a recollection of those fearful pictures of +devastation presented to our imaginations by the historical narratives of +the past, but is rather due to the sudden revelation of the delusive nature +of the inherent faith by which we had clung to a belief in the immobility of +the solid parts of the earth. We are accustomed from early childhood to +draw a contrast between the mobility of water and the immobility of the soil +on which we tread; and this feeling is confirmed by the evidence of our +senses. When, therefore, we suddenly feel the ground move beneath us, a +mysterious and natural force, with which we are previously unacquainted, is +revealed to us as an active disturbance of stability. A moment destroys the +illusion of a whole life; our deceptive faith in the repose of nature +vanishes, and we feel transported, as it were, into a realm of unknown +destructive forces. Every sound -- the faintest motion in the air -- +arrests our attention, and we no longer trust the ground on which we stand. +Animals, especially dogs and swine, participate in the same anxious +disquietude; and even the crocodiles of the Orinoco, which are at other +times as dumb as our little lizards, leave the trembling bed of the river, +and run with loud cries into the adjacent forests. + +To man the earthquake conveys an idea of some universal and unlimited +danger. We may flee from the crater of a volcano in active eruption, or +from the dwelling whose destruction is threatened by the approach of the +lava stream; but in an earthquake, direct our flight whithersoever we will, +we still feel as if we trod upon the very focus of destruction. This +condition of the mind is not of long duration, although it takes its origin +in the deepest recesses of our nature; and when a series of faint shocks +succeed one another, the inhabitants of the country soon lose every trace of +fear. On the coasts of Peru, where rain and hail are unknown, no less than +the rolling thunder and the flashing lightning, these luminous explosions of +the atmosphere are replaced by the subterranean noises which accompany +earthquakes.* + + +[footnote] *["Along the whole coast of Peru the atmosphere is almost +uniformly in a state of repose. It is not illuminated by the lightning's +flash, or disturbed by the roar of the thunder; no deluges of rain, no +fierce hurricanes, destroy the fruits of the fields, and with them the hopes +of the husbandman. But the mildness of the elements above ground is +frightfully counterbalanced by their subterranean fury. Lima is frequently +visited by earthquakes, and several times the city has been reduced to a +mass of ruins. At an average, forty-five shocks may be counted on in the +year. Most of them occur in the later part of October, in November, +December, January, May, and June. Experience gives reason to expect the +visitation of two desolating earthquakes in a century. The period between +the two is from forty to sixty years. The most considerable catastrophes +experienced in Lima since Europeans have visited the west coast of South +America happened in the years 1586, 1630, 1687, 1713, 1746, 1806. There is +reason to fear that in the course of a few years this city may be the prey +of another such visitation."] --Tr. + + +Long habit, and the very +p 217 +prevalent opinion that dangerous shocks are only to be apprehended two or +three times in the course of a century, cause faint oscillations of the soil +to be regarded in Lima with scarcely more attention than a hail storm in the +temperate zone. + +Having thus taken a general view of the activity -- the inner life, as it +were -- of the Earth, in respect to its internal heat, its electro-magnetic +tension, its emanation of light at the poles, and its irregularly-recurring +phenomena of motion, we will now proceed to the consideration of the +material products, the chemical changes in the earth's surface, and the +composition of the atmosphere, which are all dependent on planetary vital +activity. We see issue from the ground steam and gaseous carbonic acid, +almost always free from the admixture of nitrogen;* carbureted hydrogen gas, +which has been used in the Chinese province Sse-tschuan** for several +thousand years, and recently in the village of Fredonia, in the State of New +York, United States, in cooking and for illumination; sulphureted hydrogen +gas and sulphurous vapors; and, more rarely,*** sulphurous and hydrochloric +acids.**** + + +[footnote] * Bischof's comprehensive work, 'Warmelchere des inneren +Erdkorpers'. + + +[footnote] **On the Artesian fire-springs (Ho-tsing) in China, and the +ancient use of portable gas (in bamboo canes) in the city of Khiung-tsheu, +see Klaproth, in my 'Asie Centrale', t. iii., p. 519-530. + + +[footnote] *** Boussingault ('Annales de Chimie', t. lii., p. 181) observed +no evolution of hydrochloric acid from the volcanoes of New Granada, while +Monticelli found it in enormous quantity in the eruption of Vesuvius in 1813. + + +[footnote] ****[Of the gaseous compounds of sulphur, one, sulphurous acid, +appears to predominate chiefly in volcanoes possessing a certain degree of +activity, while the other, sulphureted hydrogen, has been most frequently +perceived among those in a dormant condition. The occurrence of abundant +exhalations of sulphuric acid, which have been hitherto noticed chiefly in +extinct volcanoes, as for instance, in a stream issuing from that of Purace, +between Bogota and Quito, from extinct volcanoes in Java, is satisfactorily +explained in a recent paper by M. Dumas, 'Annales de Chimie', Dec., 1846. +He shows that when sulphureted hydrogen, at a temperature above 100 degrees +Fahr., and still better when near 190 degrees, comes in contact with certain +porous bodies, a catalytic action is set up, by which water, sulphuric acid, +and sulphur are produced. Hence probably the vast deposits of sulphur, +associated with sulphates of lime and strontian, which are met with in the +western parts of Sicily.] -- Tr. + + +Such effusions +p 218 +from the fissures of the earth not only occur in the districts of still +burning or long-extinguished volcanoes, but they may likewise be observed +occasionally in districts where neither trachyte nor any other volcanic +rocks are exposed on the earth's surface. In the chain of Quindiu I have +seen sulphur deposited in mica slate from warm sulphurous vapor at an +elevation of 6832 feet* above the level of the sea, while the same species +of rock, which was formerly regarded as primitive, contains, in the Cerro +Cuello, near Tiscan, south of Quito, an immense deposit of sulphur imbedded +in pure quartz. + + +[footnote] * Humboldt, 'Recucil d'Observ. Astronomiques', t. i., p. 311 +('Nivellement Barometrique de la Cordillere des Andes', No. 206). + + +Exhalations of carbonic acid ('mofettes') are even in our days to be +considered as the most important of all gaseous emanations, with respect to +their number and the amount of their effusion. We see in Germany, in the +deep valleys of the Eifel, in the neighborhood of the Lake of Laach,* in the +crater-like valley of the Wehr and in Western Bohemia, exhalations of +carbonic acid gas manifest themselves as the last efforts of volcanic +activity in or near the foci of an earlier world. + + +[footnote] *[The Lake of Laach, in the district of the Eifel, is an expanse +of water two miles in circumference. The thickness of the vegetation on the +sides of its crater-like basin renders it difficult to discover the nature +of the subjacent rock, but it is probably composed of black cellular augitic +lava. The sides of the crater present numerous loose masses, which appear +to have been ejected, and consist of glassy feldspar, ice-spar, sodalite, +hauyne, spinellane, and leucite. The resemblance between these products and +the masses formerly ejected from Vesuvius is most remarkable. (Daubeney 'On +Volcanoes', p. 81.) Dr. Hibbert regards the Lake of Laach as formed in the +first instance by a crack caused by the cooling of the crust of the earth, +which was widened afterward into a circular cavity by the expansive force of +elastic vapors. See 'History of the Extinct Volcanoes of the Basin of +Neuwied', 1832.] -- Tr. + + +In those earlier periods, when a higher terrestrial temperature existed, and +when a great number of fissures still remained unfilled, the processes we +have described acted more powerfully, and carbonic acid and hot steam were +mixed in larger quantities in the atmosphere, from whence it follows, as +Adolph Bronguiart has ingeniously shown,* that the primitive vegetable world +must have exhibited almost every where, and independently of geographical +position, the most luxurious abundance and the fullest development of +organism. + + +[footnote] *Adolph Bronguiart, in the 'Annales des Sciences Naturelles', t. +xv., p. 225. + + +In these constantly warm and damp atmospheric strata, saturated with +p 219 +carbonic acid, vegetation must have attained a degree of vital activity, and +derived the superabundance of nutrition necessary to furnish materials for +the formation of the beds of lignite (coal) constituting the inexhaustible +means on which are based the physical power and prosperity of nations. Such +masses are distributed in basins over certain parts of Europe, occurring in +large quantities in the British Islands, in Belgium, in France, in the +provinces of the Lower Rhine, and in Upper Silesia. At the same primitive +period of universal volcanic activity, those enormous quantities of carbon +must also have escaped from the earth which are contained in limestone +rocks, and which, if seprated from oxygen and reduced to a solid form, would +constitute about the eighth part of the absolute bulk of these mountain +masses.* + + +[footnote] * Bischof, op. cit., s. 324, Anm. 2. + + +That portion of the carbon which was not taken up by alkaline earths, but +remained mixed with the atmosphere, as carbonic acid, was gradually consumed +by the vegetation of the earlier stages of processes of vegetable life, only +retained the small quantity which it now possesses, and which is not +injurious to the sulphurous vapor have occasioned the destruction of the +species of mollusca and fish which inhabited the inland waters of the +earlier world, and have given rise to the formation of the contorted beds of +gypsum, which have doubtless been frequently affected by shocks of +earthquakes. + +Gaseous and liquid fluids, mud, and molten earths, ejected from the craters +of volcanoes, which are themselves only a kind of "intermittent springs," +rise from the earth under precisely analogous physical relations.* + + +[footnote] *Humboldt, 'Asie Centrale', t. i., p. 43. + + +All these substances owe their temperature and their chemical character to +the place of their origin. The 'mean' temperature of aqueous springs is +less than that of the air at the point whence they emerge, if the water flow +from a height; but their heat increases with the depth of the strata with +which they are in contact at their origin. We have already spoken of the +numerical law regulating this increase. The blending of waters that have +come from the height of a mountain with those that have sprung from the +depths of the earth, render it difficult to determine the position of the +'isogeothermal lines'* (lines of equal internal +p 220 +terrestrial temperature, when this determination is to be made from the +temperature of flowing springs. + + +[footnote] *On the theory of isogeothermal (chthonisothermal) lines, +consult the ingenious labors of Kupffer, in Pogg, 'Annalen', bd xv., s. 184, +and bd xxxii., s. 270, in the 'Voyage dans l'Oural', p. 382-298, and in the +'Edinburgh Journal of Science', New Series, vol. iv., p. 355. See, also, +Kamtz, 'Lehrb. der Meteor.', bd. ii., s. 217; and, on the ascent of the +chthonisothermal lines in mountainous districts, Bischof, s. 174-198. + + +Such at any rate, is the result I have arrived at from my own observations +and those of my fellow-travelers in Northern Asia. The temperature of +springs, which has become the subject of such continuous physical +investigation during the last half century, depends, like the elevation of +the line of perpetual snow, on very many simultaneous and deeply-involved +causes. It is a function of the temperature of the stratum in which they +take their rise, of the specific heat of the soil, and of the quantity and +temperature of the meteoric water,* which is itself different from the +temperature of the lower strata of the atmosphere, according to the +different modes of its origin in rain, snow, or hail.** + + +[footnote] *Leop. v. Buch, in Pogg., 'Annalen', bd. xii., s. 405. + + +[footnote] ** On the temperature of the drops, of rain in Cumana, which +fell to 72 degrees, when the temperature of the air shortly before had been +86 degrees and 88 degrees, and during the rain sank to 74 degrees, see my +'Relat. Hist.', t. ii., p. 22. The rain-drops, while falling, change the +normal temperature they originally possessed, which depends on the height of +the clouds from which they fell, and their heating on their upper surface by +the solar rays. The rain-drops, on their first production, have a higher +temperature than the surrounding medium in the superior strata of our +atmosphere, in consequence of the liberation of their latent heat; and they +continue to rise in temperature, since, in falling through lower and warmer +strata, vapor is precipitated on them, and they thus increase in size +(Bischof, 'Warmelehre des inneren Erdkorpers' s. 73); but this additional +heating is compensated for by evaporation. The cooling of the air by rain +(putting out of the question what probably belongs to the electric process +in storms) is effected by the drops, which are themselves of lower +temperature, in consequence of the cold situation in which they were formed, +and bring down with them a portion of the higher colder air, and which +finally, by moistening the ground, give rise to evaporation. The cooling of +the air by rain (putting out of the question what probably belongs to the +electric process in storms) is effected by the drops, which are themselves +of lower temperature, in consequence of the cold situation in which they +were formed, and bringi down with them a portion of the higher colder air, +and which finally, by moistening the ground, give rise to evaporation. +These are the ordinary relations of the phenomenon. When, as occasionally +happens, the rain-drops are warmer than the lower strata of the atmosphere +(Humboldt, 'Rel. Hist.', t. iii., p. 513), the cause must probably be sought +in higher warmer currents, or in a higher temperature of widely-extended and +not very thick clouds, from the action of the sun's rays. How, moreover, +the phenomenon of supplementary rainbows, which are explained by the +interference of light, is connected with the original and increasing size of +the falling drops, and how an optical phenomenon, if we know how to observe +it accurately, may enlighten us regarding a meteorological process, +according to diversity of zone, has been shown, with much talent and +ingenuity, by Arago, in the 'Annuaire' for 1836, p. 300. + + +Cold springs can only indicate the mean atmospheric temperature +p 221 +when they are unmixed with the waters rising from great depths, or +descending from considerable mountain elevations, and when they have passed +through a long course at a depth from the surface of the earth which is +equal in our latitudes to 40 or 60 feet, and according to Boussingault, to +about one foot in the equinoctial regions,* these being the depths at which +the invariability of the temperature begins in the temperate and torrid +zones, that is to say, the depths at which horary, diurnal, and monthly +changes of heat in the atmosphere cease to be perceived. + + +[footnote] * The profound investigations of Boussingault fully convince me, +that in the tropics, the temperature of the ground, at a very slight depth, +exactly corresponds with the mean temperature of the air. The following +instances are sufficient to illustrate this fact: + +________________________________________________________ +Stations Temperature at Mean Height, in +within 1 French foot Temperature English +Tropic [1.006 of the of the feet, above +Zones. English foot] air. the level + below the of the sea. + earth's surface. +________________________________________________________ + +Guayaquil 78.8 78.1 0 +Anserma Nuevo 74.6 74.8 3444 +Zupia 70.7 70.7 4018 +Popayan 64.7 65.6 5929 +Quito 59.9 59.9 9559 +________________________________________________________ + +The doubts about the temperature of the earth within the tropics, of which I +am probably, in some degree, the cause, by my observations on the Cave of +Caripe (Cueva del Guacharo), 'Rel. Hist.', t. iii., p. 191-196), are +resolved by the consideration that I compared the presumed mean temperature +of the air of the convent of Caripe, 65.3 degrees, not with the temperature +of the air of the cave, 65.6 degrees, but with the temperature of the +subterranean stream, 62.3degrees, although I observed ('Rel. Hist.', t. +iii., p. 146 and 195) that mountain water from a great height might probably +be mixed with the water of the cave. + + +Hot springs issue from the most various kinds of rocks. The hottest +permanent springs that have hitherto been observed are, as my own researches +confirm, at a distance from all volcanoes. I will here advert to a notice +in my journal of the Aguas Calientes de las Trincheras', in South America, +between Porto Cabello and Nueva Valencia, and the 'Aguas de Comangillas', in +the Mexican territory, near Guanaxuato; the former of these, which issued +from granite, had a temperature of 194.5 degrees; the latter, issuing from +basalt, 205.5degrees. The depth of the source from whence the water flowed +with this temperature, judging from what we know of the law of the increase +of heat in the interior of the earth, was probably 7140 feet, or above two +miles. If the universally-diffused terrestrial heat be the cause of thermal +springs, as of active volcanoes, the rocks can only exert an influence by +the different capacities +p 222 +for heat and by their conducting powers. The hottest of all permanent +springs (between 203 degrees and 209 degrees) are likewise, in a most +remarkable degree, the purest, and such as hold in solution the smallest +quantity of mineral substances. Their temperature appears, on the whole, to +be less constant than that of springs between 122 degrees and 165 degrees, +which in Europe, at least, have maintained, in a most remarkable manner, +their 'invariability of heat and mineral contents' during the last fifty or +sixty years, a period in which thermometrical measurements and chemical +analyses have been applied with increasing exactness. Boussingault found in +1823 that the thermal springs of Las Tricheras had risen 12 degrees during +the twenty-three years that had intervened since my travels in 1800.* + + +[footnote] *Boussingault, in the 'Annales de chimie', t. lii., p. 181. The +spring of Chaudes Aigues, in Auvergne, is only 176degrees. It is also to be +observed, that while the Aguas Calientes de las Trincheras, south of Porto +Cabello (Venezuela), springing from granite cleft in regular beds, and far +from all volcanoes, have a temperature of fully 206.6 degrees, all the +springs which rise in the vicinity of still active volcanoes (Pasto, +Cotopaxi, and Tunguragua) have a temperature of only 97 - 130 degrees. + + +This calmly-flowing spring is therefore now nearly 12 degrees hotter than +the intermittent fountains of the Geyser and the Strokr, whose temperature +has recently been most carefully determined by Krug of Nidda. A very +striking proof of the origin of hot springs by the sinking of cold meteoric +water into the earth, and by its contact with a volcanic focus, is afforded +by the volcano of Jorulla in Mexico, which was unknown before my American +journey. When, in September, 1759, Jorullo was suddenly elevated into a +mountain 1183 feet above the level of the surrounding plain, two small +rivers, the 'Rio de Cuitimba' and 'Rio de San Pedro', disappeared, and some +time afterward burst forth again, during violent shocks of an earthquake, as +hot springs, whose temperature I found in 1803 to be 186.4 degrees. + +The springs in Greece still evidently flow at the same places as in the +times of Hellenic antiquity. The spring of Erasinos, two hours' journey to +the south of Argos, on the declivity of Chaon, is mentioned by Herodotus. +At Delphi we still see Cassotis (now the springs of St. Nicholas) rising +south of the Lesche, and flowing beneath the Temple of Apollo; Castalia, at +the foot of Phaedriadae; Pirene, near Acro-Corinth; and the hot baths of +Aedipsus, in Euboea, in which Sulla bathed during the Mithridatic war.* + + +[footnote] *Cassotis (the spring of St. Nicholas) and Castalia, at the +Phaedriadae, mentioned in Pausanias, x., 24, 25, and x., 8, 9; Pirene +(Acro-Corinth), in Strabo, p. 379; the spring of Erasinos, at Mount Chaon, +south of Argos, in Herod., vi., 67, and Pausanias, ii., 24, 7; the springs +of Aedipsus in Euboea, some of which have a temperature of 88 degrees, while +in others it ranges between 144) qne 167 degrees, in Strabo, p. 60 and 447, +and Athenaeus, ii., 3, 73; the hot springs of Thermopylae, at the foot of +Oeta, with a temperature of 149 degrees. All from manuscript notes by +Professor Curtius, the learned companion of Otfried Muller. + + +I advert with pleasure to these +p 223 +facts, as they show us that, even in a country subject to frequent and +violent shocks of earthquakes, the interior of our planet has retained for +upward of 2000 years its ancient configuration in reference to the course of +the open fissures that yield a passage to these waters. The 'Fontaine +jaillissante' of Lillers, in the Department des Pas de Calais, which was +bored as early as the year 1126, still rises to the same height and yields +the same quantity of water; and, as another instance, I may mention that the +admirable geographer of the Caramanian coast, Captain Beaufort, saw in the +district of Phaselis the same flame fed by emissions of inflammable gas +which was described by Pliny as the flame of the Lycian Chimera.* + + +[footnnote] (Pliny, ii., 106; Seneca, 'Epist.' 79, 3, ed. Ruhkopf +(Beaufort, 'Survey of the Coast of Karamania', 1820, art. Yanar, near +Delktasch, the ancient Phaselis, p. 24). See also Ctesias, 'Fragm.', cap. +10 p. 250, ed. Bahr; Strabo, lib. xiv., p. 666, Casaub. +["Not far from the Deliktash, on the side of a mountain, is the perpetual +fire described by Captain Beaufort. The travelers found it as brilliant as +ever, and even somewhat increased; for, besides the large flame in the +corner of the ruins described by Beaufort, there were small jets issuing +from crevices in the side of the crater-like cavity five or six feet deep. +At the bottom was a shallow pool of sulphureous and turbid water, regarded +by the Turks as a sovereign remedy for all skin complaints. The soot +deposited from the flames was regarded as efficacious for sore eyelids, and +valued as a dye for the eyebrows." See the highly interesting and accurate +work, 'Travels in Lycia', by Lieut. Spratt and Professor E. Forbes.] -- Tr. + + +The observation made by Arago in 1821, that the deepest Artesian wells are +the warmest,* threw great light on the origin of thermal springs, and on the +establishment of the law that terrestrial heat increases with increasing +depth. + + +[footnote] *Arago, in the 'Annuaire pour' 1835, p. 234. + + +It is a remarkable fact, which has but recently been noticed, that at the +close of the third century, St. Patricus,* probably Bishop of Pertusa, was +led to adopt very correct views regarding the phenomenon of the hot springs +at Carthage. + + +[footnote] *'Acta S. Patricii', p. 555, ed. Ruinart, t. ii., p. 385, +Mazochi. Dureau de la Malle was the first to draw attention to this +remarkable passage in the 'Recherches sur la Topographie de Carthage', 1835, +p. 276. (See, also, Seneca, 'Nat. Quaest.', iii., 24.) + + +On being asked what was the cause of boiling water bursting from the earth, +he replied, "Fire is nourished in the clouds and in the interior +p 224 +of the earth, as Aetna and other mountains near Naples may teach you. The +subterranean waters rise as if through siphons. The cause of hot springs is +this: waters which are more remote from the subterranean fire are colder, +while those which rise nearer the fire are heated by it, and bring with them +to the surface which we inhabit an insupportable degree of heat." + +As earthquakes are often accompanied by eruptions of water and vapors, we +recognize in the 'Salses',* of small mud volcanoes, a transition from the +changing phenomena presented by these eruptions of vapor and thermal springs +to the more powerful and awful activity of the streams of lava that flow +from volcanic mountains. + + +[footnote] *[True volcanoes, as we have seen, generate sulphureted hydrogen +and muriatic acid, upheave tracts of land, and omit streams of melted +feldspathic materials; salses, on the contrary, disengage little else but +carbureted hydrogen, together with bitumen and other products of the +distillation of coal, and pour forth no other torrents except of mud, or +argillaceous materials mixed up with water. Daubeney, op cit., p. 540.] -- +Tr. + + +If we consider these mountains as springs of molten earths producing +volcanic rocks, we must remember that thermal water, when impregnated with +carbonic acid and sulphurous gases, are continually forming horizontally +ranged strata of limestone (travertine) or conical elevations, as in +Northern Africa (in Alberia), and in the Banos of Caxamarca, on the western +declivity of the Peruvian Cordilleras. The travertine of Van Diemen's Land +(near Hobart Town) contains, according to Charles Darwin, remains of a +vegetation that no longer exists. Lava and travertine, which are constantly +forming before our eyes, present us with the two extremes of geognostic +relations. + +'Salses' deserve more attention than they have hitherto received from +geognosists. Their grandeur has been overlooked because of the two +conditions to which they are subject; it is only the more peaceful state, in +which they may continue for centuries, which has generally been described: +their origin is, however, accompanied by earthquakes, subterranean thunder, +the elevation of a whole district, and lofty emissions of flame of short +duration. When the mud volcano of Jokmali began to form on the 27th of +November, 1827, in the peninsula of Abscheron, on the Caspian Sea, east of +Baku, the flames flashed up to an extraordinary height for three hours, +while during the next twenty hours they scarcely rose three feet above the +crater, from which mud was ejected. Near the village of Baklichli, west of +Baku, the flames rose so high that +p 225 +they could be seen at a distance of twenty-four miles. Enormous masses of +rock were torn up and scattered around. Similar masses may be seen round +the now inactive mud volcano of Monte Ziblo, near Sassuolo, in Northern +Italy. The secondary condition of repose has been maintained for upward of +fifteen centuries in the mud volcanoes of Girgenti, the 'Macalubi', in +Sicily, which have been described by the ancients. These salses consist of +many contitiguous conical hills, from eight to ten, or even thirty feet in +height, subject to variations of elevation as well as of form. Streams of +argillaceous mud, attended by a periodic development of gas, flow from the +small basins at the summits, which are filled with water; the mud, although +usualy cold is sometimes at a high temperature, as at Damak, in the province +of Samarang, in the island of Java. The gases that are developed with loud +noise differ in their nature consisting for instance, of hydrogen mixed with +naphtha, or of carbonic acid, or, as Parrot and myself have shown (in the +peninsula of Taman, and in the 'Volcancitos de Turbaco', in South America), +of almost pure nitrogen.* + + +[footnote] *Humboldt, 'Rel. Hist.', t. iii., p. 562-567; 'Asie Centrale', +t. i., p. 43; t. ii., p. 505-515; 'Vues des Cordilleres', pl. xli. +Regarding the 'Macalubi', the 'overthrown' or 'inverted', from the word +'Khalaba'), and on "the Earth ejecting fluid earth," see Solinus, cap. 5: +"idem ager Agrigentinus eructat limosas scaturigenes, et ut venae fontium +sufficiunt rivis subjinistrandis, ita in hac Sicilae parte solo munquam +deficiente, Aeterna rejectatione terram terra evomit." + + +Mud volcanoes, after the first violent explosion of fire, which is not, +perhaps, in an equal degree common to all, present to the spectator an image +of the uninterrupted but weak activity of the interior of our planet. The +communication with the deep strata in which a high temperature prevails is +soon closed, and the coldness of the mud emissions of the salses seems to +indicate that the seat of the phenomenon can not be far removed from the +surface during their ordinary condition. The reaction of the interior of +the earth on its external surface is exhibited with totally different force +in true volcanoes or igneous mountains, at points of the earth in which a +permanent, or, at least, continually-renewed connection with the volcanic +force is manifested. We must here carefully distinguish between the more or +less intensely developed volcanic phenomena, as for instance, between +earthquakes, thermal, aqueous, and gaseous springs, mud volcanoes, and the +appearance of bell-formed or dome-shaped trachytic rocks without openings; +the opening of these rocks, or of the elevated beds of basalt, as +p 226 +craters of elevation; and, lastly, the elevation of a permanent volcano in +the crater of elevation, or among the 'debris' of its earlier formation. At +different periods, and in different degrees of activity and force, the +permanent volcanoes emit steam acids, luminous scoriae, or, when the +resistance can be overcome, narrow, band-like streams of molten earths. +Elastic vapors sometimes elevate either separate portions of the earth's +crust into dome-shaped unopened masses of feldspathic trachyte and dolerite +(as in Puy de Dome and Chimborazo), in consequence of some great or local +manifestation of force in the interior of our planet, or the upheaved strata +are broken through and curved in such a manner as to form a steep rocky +ledge on the opposite inner side, which then constitutes the inclosure of a +crater of elevation. If this rocky ledge has been uplifted from the bottom +of the sea, which is by no means always the case, it determines the whole +physiognomy and form of the island. In this manner has arisen the circular +form of Palma, which has been described with such admirable accuracy by +Leopold von Buch, and that of Nisyros,* in the Aegean sea. + + +[footnote] *See the interesting little map of the island of Nisyros, in +Roise's 'Reisen auf den Griechischen Inseln', bd. ii., 1843, s. 69. + + +Sometimes half of the annular ledge has been destroyed, and in the bay +formed by the encroachment of the sea corallines have built their cellular +habitations. Even on continents craters of elevation are often filled with +water, and embellish in a peculiar manner the character of the landscape. +Their origin is not connected with any determined species of rock: they +break out in basalt, trachyte, leucitic porphyry (somma), or in doleritic +mixtures of augite and labradorite; and hence arise the different nature and +external conformation of these inclosures of craters. No phenomena of +eruption are manifested in such craters, as they open no permanent channel +of communication with the interior, and it is but seldom that we meet with +traces of volcanic activity either in the neighborhood or in the interior of +these craters. The force which was able to produce so important an action +must have been long accumulating in the interior before it could overpower +the resistance of the mass pressing upon it; it sometimes, for instance, on +the origin of new islands, will raise granular rocks and conglomerated +masses (strata of tufa filled with marine plants) above the surface of the +sea. The compressed vapors escape through the crater of elevation, but a +large mass soon falls back and closes the opening, which had been only +formed by these manifestations of force. No volcano can, therefore, +p +be produced.* + + +[footnote] *Leopold von Buch, 'Phys. Beschreibung der Canarischen Inseln', +s. 326; and his Memoir 'uber Erhebungscratere und Vulcane', in Poggend., +'Annal.', bd. xxxvii., s. 169. +In his remarks on the separation of Sicily from Calabria, Strbo gives an +excellend description of the two modes in which islands are formed: "Some +islands," he observes (lib. vi., p. 258, ed. Casaub.), "are fragments of the +continent, others have arisen from the sea, as even at the present time is +known to happen; for the islands of the great ocean, lying far from the main +land, have probably been raised from its depths, while, on the other hand, +those near promontories appear (according to reason) to have been separated +from the continent." + + +A volcano, properly so called, exists only where a permanent connection is +established between the interior of the earth and the atmosphere, and the +reaction of the interior on the surface then continues during long periods +of time. It may be interrupted for centuries, as in the case of Vesuvius +Fisove,* and then manifest itself with renewed activity. + + +[footnote] *Ocre Fisove (Mons Vesuvius) in the Umbrian language. (Lassen +'Deutung der Eugubinischen Tafeln in Rhein. Museum', 1832, s. 387.) The +word 'ochre' is very probaby genuine Umbrian, and means, according to +Festus, 'mountain'. Aetna would be a burning and shining mountain, if Voss +is correct in stating that [Greek work] is an Hellenic sound, and is +connected with [Greed word] and [Greek word]; but the intelligent writer +Parthey doubts this Hellenic origin on etymological grounds, and also +because etna was by no means regarded as a luminous beacon for ships or +wanderers, in the same manner as the ever-travailing Stromboli (Strongyle), +to which Homer seems to refer in the Odyssey (xii., 68, 202, and 219), and +its geographical position was not so well determined. I suspect that tna +would be found to be a Sicilian word, if we had any fragmentary materials to +refer to. According to Diodorus (v., 6), the Sicani, or aborigines +preceding the Sicilians, were compelled to fly to the western part of the +island, in the consequence of successive eruptions extending over many +years. The most ancient eruption of Mount Aetna on record is that mentioned +by Pindar and Schylus, as occurring under Hiero, in the second year of the +75th Olympiad. It is probable that Hesiod was aware of the devastating +eruptions of Aetna before the period of Greek immigration. There is, +however, some doubt regarding the work [Greek word] in the text of Hesiod, a +subject into whci I have entered at some length in another place. +(Humboldt, 'Examen Crit. de le Geogr.', t. i., p. 168.) + + +In the time of Nero, men were disposed to rank Aetna among the volcanic +mountains which were graduallybecoming extinct,* and subsequently Aelian** +even maintained that mariners could no longer see the sinking summit of the +mountain from so great a distance at sea. + +[footnote] *Seaeca. 'Epist.', 79. + +[footnote] ** Aelian, 'Var. Hist.', viii., 11. + + +Where these evidences -- these old scaffoldings of eruption, I might almost +say -- still exist, the volcano rises from a crater of elevation, while a +high rocky wall surrounds, like an amphitheater, the isolated conical mount, +and forms around it a kind of easing of highly elevated +p 228 +strata. Occasionally not a trace of this inclosure is visible, and the +volcano, which is not always conical rises immediately from the neighboring +plateau in an elongated form, as in the case of Pichincha,* at the foot of +which lies the city of Quito. + + +[footnote] *[This mountain contains two funnel-shaped craters, apparently +resulting from two set of eruptions: the western nearly circular, and +having in its center a cone of eruption, from the summit and sides of which +are no less than seventy vents, some in activity and others extinct. It is +probable that the larger number of the vents were produced at periods +anterior to history. Caubney, op. cit., p. 488.] -- Tr. + + +As the nature of rocks, or the mixture (grouping) of simple minerals into +granite, gneiss, and mica slate, or into trachyte, basalt, and dolorite, is +independent of existing climates, and is the same under the most varied +latitudes of the earth, so also we find every where in inorganic nature that +the same laws of configuration regulate the reciprocal superposition of the +strata of the earth's crust, cause them to penetrate one another in the form +of veins, and elevate them by the agency of elastic forces. This constant +recurrence of the same phenomena is most strikingly manifested in volcanoes. + When the mariner, amid the islands of some distant archipelago, is no +longer guided by the light of the same stars with which he had been familiar +in his native latitude, and sees himself surrounded by palms and other forms +of an exotic vegetation, he still can trace, reflected in the individual +characteristics of the landscape, the forms of Vesuvius, of the come-shaped +summits of Auvergne, the craters of elevation in the Canaries and Azores, or +the fissures of eruption in Iceland. A glance at the satellite of our +planet will impart a wider generalization to this analogy of configuration. +by means of the charts that have been drawn in accordance with the +observations made with large telescopes, we may recognize in the moon, where +water and air are both absent, vast craters of elevation surrounding or +supporting conical mountains, thus affording incontrovertible evidence of +the effects produced by the reaction of the interior on the surface, favored +by the influence of a feebler force of gravitation. + +Although vocanoes are justy termed in many languages "fire-emitting +mountains," mountains of this kind are not formed by the gradual +accumulation of ejected currents of lava, but their origin seems rather to +be a general consequence of the sudden elevation of soft masses of trachyte +or labradoritic augite. The amount of the elevating force is manifested +p 229 +by the elevation of the volcano, which varies from the inconsiderable height +of a hill (as the volcano of Cosima, one of the Japanese Kurile islands) to +that of a cone above 19,000 feet in height. It has appeared to me that +relations of height have a great influence on the occurrence of eruptions, +which are more frequent in low than in elevated volcanoes. I might instance +the series presented by the following mountains: Stromboli, 2318 feet; +Guacamayo, in the province of Quixos, from which detonations are heard +almost daily (I myself often heard them at Chillo, near Quito, a distance of +eighty-eight miles); Vesuvius, 3876 feet; Aetna, 10871 feet; the Peak of +Teneriffe, 12,175 feet; and Cotopaxi, 19,069 feet. If the focus of these +volcanoes be at an equal depth below the surface, a greater force must be +required where the fused masses have to be raised to an elevation six or +eight times greater than that of the lower eminences. While the volcano +Stromboli (Strongyle) has been incessantly active since the Homeric ages, +and has served as a beacon-light to guide the mariner in the Tyrrhenian Sea, +loftier volcanoes have been characterized by loong intervals of quiet. Thus +we see that a whole century often intervenes between the eruptions of most +of the colossi which crown the summits of the Cordilleras of the Andes. +Where we meet with exceptions to this law, to which I long since drew +attention, they must depend upon the circumstance that the connections +between the volcanic foci and the crater of eruption can not be considered +as equaly permanent in the case of all volcanoes. The channel of +communication may be closed for a time in the case of the lower ones, so +that they less frequently come to a state of eruption, although they do not, +on that account, approach more nearly to their final extinction. + +These relations between the absolute height and the frequency of volcanic +eruptions, as far as they are externally perceptible, are intimately +connected with the consideration of the local conditions under which lava +currents are erupted. Eruptions from the crater are very unusual in many +mountains, generally occurring from lateral fissures (as was observed in the +case of Aetna, in the sixteenth century, by the celebrated historian Bembo, +when a youth*), whenever the sides +p 230 +of the upheaved mountain were least able, from their configuration and +position, to offer any resistance. + +[footnote] *Petri Bembi Opuscula ('Aetna Dialogus'), Basil, 1556, p. 63: +"Quicquid in Aetnae matris utero coulescit, nunquam exit ex cratere +superiore, quod vel eo inscondere gravis materia non queat, vel, quia +inferius alia spiramenta sunt, non fit opus. Despumant flammis urgentibus +ignei rivi pigro fluxu totas delambentes plagas, et in lapidem indurescunt." + + +Cones of eruption are sometimes uplifted on these fissures; the larger ones, +which are erroneously termed 'new volcanoes', are ranged together in line +marking the direction of a fissure, which is soon reclosed, while the +smaller ones are grouped together covering a whole district with their +dome-like or hive-shaped forms. To the latter belong the 'hornitos de +Jorullo',I the cone of Vesuvius erupted in October, 1822, that of Awatscha, +according to Postels, and those of the lava-field mentioned by Erman, near +the Baidar Mountains, in the peninsula of Kamtschatka. + + +[footnote] See my drawing of the volcano of Jorullo, of its 'hornitos', and +of the uplifted 'malpays', in my 'Vues de Cordilleres', pl. xliii., p. 239. +[Burckhardt states that during the twenty-four years that have intervened +since Baron Humboldt's visit to Jorullo, the 'hornitos' have either wholly +disappeared or completely changed their forms. See 'Aufenthalt und Reisen +in Mexico in 1825 und 1834'.] -- Tr. + + +When volcanoes are not isolated in a plain, but surrounded, as in the double +chain of the Andes of Quito, by a table-land having an elevation from nine +to thirteen thousand feet, this circumstance may probably explain the cause +why no lava streams are formed* during the most dreadful eruption of ignited +scoriae accompanied by detonations heard at a distance of more than a +hundred miles. + + +[footnote] * Humboldt, 'Essaii sur la Geogr. des Plantes et Tableau Phys. +des Regions Equinoxiales', 1807, p. 130, and 'Essai Geogn. sur le Gisement +des Roches', p. 321. Most of the volcanoes in Java demonstrate that the +cause of the perfect absence of lava streams in volcanoes of incessant +activity is not alone to be sought for in their form, position, and height. +Leop. von Buch, 'Descr. Phys. des Iles Canaries', p. 419; Reinwardt and +Hoffmann, in Poggened., 'Annalen.', bd. xii., s. 607. + + + +Such are the volcanoes of Popayan, those of the elevated plateau of Los +Pastos and of the Andes of Quito, with the exception, perhaps, in the case +of the latter, of the volcano of Antisana. The height of the cone of +cinders, and the size and form of the crater, are elements of configuration +which yield an especial and individual character to volcanoes, although the +cone of cinders and the crater are both wholly independent of the dimensions +of the mountain. Vesuvius is more than three times lower than the Peak of +Teneriffe; its cone of cinders rises to one third of the height of the whole +mountain, while the cone of cinders of the Peak is only 1/22d of its +altitude. + + +[footnote] * [It may be remarked in general, although the rule is liable to +exceptions, that the dimensions of a crater are in an inverse ratio to the +elevation of the mountain. Daubeney, op. Cit., p. 444.] -- Tr. + + +In a much higher volcano than that of Teneriffe, the Rueu Pichincha, other +relations occur +p 231 +which approach more nearly to that of Vesuvius. Among all the volcanoes +that I have seen in the two hemispheres, the conical form of Cotopaxi is the +most beautifully regular. A sudden fusion of the snow at its cone of +cinders announces the proximity of the eruption. Before the smoke is +visible in the rarefied strata of air surrounding the summit and the opening +of the crater, the walls of the cone of cinders are sometimes in a state of +glowing heat, when the whole mountain presents an appearance of the most +fearful and portentous blackness. The crater, which, with very few +exceptions, occupies the summit of the volcano, forms a deep, caldron-like +valley, which is often accessible, and whose bottom is subject to constant +alterations. The great or lesser depth of the crater is in many volcanoes +likewise a sign of the near or distant occurrence of an eruption. Long, +narrow fissures, from which vapors issue forth, or small rounding hollows +filled with molten masses, alternately open and close in the caldron-like +valley; the bottom rises and sinks, eminences of scoriae and cones of +eruption are formed, rising sometimes far over the walls of the crater, and +continuing for years together to impart to the volcano a peculiar character, +and then suddenly fall together and disappear during a new eruption. The +openings of these cones of eruption, which rise from the bottom of the +crater, must not, as is too often done, be confounded with the crater which +incloses them. If this be inaccessible from extreme depth and from the +perpendicular descent, as in the case of the volcano of Rucu Pichincha, +which is 15,920 feet in height, the traveler may look from the edge on the +summit of the mountains which rise in the sulphurous atmosphere of the +valley at his feet; and I have never beheld a grander or more remarkable +picture than that presented by this volcano. In the interval between two +eruptions, a crater may either present no luminous appearance, showing +merely open fissures and ascending vapors, or the scarcely heated soil may +be covered by eminences of scoriae, that admit of being approached without +danger, and thus present to the geologist the spectacle of the eruption of +burning and fused masses, which fall back on the ledge of the cone of +scoriae, and whose appearance is regularly announced by small wholly local +earthquakes. Lava sometimes streams forth from the open fissures and small +hollows, without breaking through or escaping beyond the sides of the +crater. If, however, it does break through, the newly-opened terrestrial +stream generally flows in such a quiet and well-defined course, that the +deep valley, which we term the crater, remains accessible +p 232 +even during periods of eruption. It is impossible, without an exact +representation of the configuration -- the normal type, as it were, of +fire-emitting mountains, to form a just idea of those phenomena which, owing +to fantastic descriptions and an undefined phraseology, have long been +comprised under the head of 'craters, cones of eruption', and 'volcanoes'. +The marginal ledges of craters vary much less than one would be led to +suppose. A comparison of Saussure's measurements with my own yields the +remarkable result, for instance, that in the course of forty-nine years +(from 1773 to 1822), the elevation of the northwestern margin of Mount +Vesuvius ('Rocca del Palo') may be considered to have remained unchanged.* + + +[footnote] *See the ground-work of my measurements compared with those of +Saussure and Lord Minto, in the 'Abhandlungen der Akademie der Wiss. zu +Berlin' for the years 1822 and 1823. + + +Volcanoes which, like the chain of the Andes, lift their summits high above +the boundaries of the region of perpetual snow, present peculiar phenomena. +The masses of snow, by their sudden fusion during eruptions, occasion not +only the most fearful inundations and torrents of water, in which smoking +scoriae are borne along on thick masses of ice, but they likewise exercise a +constant action, while the volcano is in a state of perfect repose, by +infiltration into the fissures of the trachytic rock. Cavities which are +either on the declivity or at the foot of the mountain are gradually +converted into subterranean resevoirs of water, which communicate by +numerous narrow openings with mountain streams, as we see exemplified in the +highlands of Quito. the fishes of these rivulets multiply, especially in +the obscurity of the hollows; and when the shocks of earthquakes, which +precede all eruptions in the andes, have violently shaken the whole mass of +the volcano, these subterranean caverns are suddenly opened, and water, +fishes, and tufaceous mud are all ejected together. It is through this +singular phenomenon* that the inhabitants of the highlands of Quito became +acquainted with the existence of the little cyclopic fishes, termed by them +the prenadilla. + + +[footnote] *Pimelodes cyclopum. See Humboldt, 'Recueil d'Observations de +Zoologie et d'Anatomie Comparee', t. i., p. 21-25. + + +On the night between the 19th and 20th of June, 1698, when the summit of +Carguairazo, a mountain 19,720 feet in height, fell in, leaving only two +huge masses of rock remaining of the ledge of the crater, a space of nearly +thirty-two square miles was overflowed and devastated by streams of liquid +tufa and argillaceous mud ('lodazales'), containing large quantities of dead +fish. +p 233 +In like manner, the putrid fever, which raged seven years previously in the +mountain town of Ibarra, north of Quito, was ascribed to the ejection of +fish from the volcano of Imbaburu.* + + +[footnote] *[It would appear, as there is no doubt that these fishes +proceed from the mountain itself, that there must be large lakes in the +interior, which in ordinary season are out of the immediate influence of the +volcanic action. See Daubeney, op. cit., p. 488, 497.] -- Tr. + + +Water and mud, which flow not from the crater itself, but from the hollows +in the trachytic mass of the mountain, can not, strictly speaking, be +classed among volcanic phenomena. They are only indirectly connected with +the volcanic activity of the mountain, resembling, in that respect, the +singular meteorological process which I have designated in my earlier +writings by the term of 'volcanic storm'. The hot stream which rises from +the crater during the eruption and spreads itself in the atmosphere, +condenses into a cloud, and surrounds the column of fire and cinders which +rises to an altitude of many thousand feet. The sudden condensation of the +vapors, and, as Gay-Lussac has shown, the formation of a cloud of enormous +extent, increase the electric tension. Forked lightning flashes from the +column of cinders, and it is then easy to distinguish (as at the close of +the eruption of Mount Vesuvius, in the latter end of October, 1822) the +rolling thunder of the volcanic storm from the detonations in the interior +of the mountain. the flashes of lightning that darted from the volcanic +cloud of steam, as we learn from Olafsen's report, killed eleven horses and +two men, on the eruption of the volcano of Katlagia, in Iceland, on the 17th +of October, 1755. + +Having thus delineated the structure and dynamic activity of volcanoes, it +now remains for us to throw a glance at the differences existing in their +material products. The subterranean forces sever old combinations of matter +in order to produce new ones, and they also continue to act upon matter as +long as it is in a state of liquefaction from heat, and capable of being +displaced. The greater or less pressure under which merely softened or +wholly liquid fluids are solidified, appears to constitute the main +difference in the formation of Plutonic and volcanic rocks. The mineral +mass which flows in narrow, elongated streams from a volcanic opening (an +earth-spring), is called lava. where many such currents meet and are +arrested in their course, they expand in width, filling large basins, in +which they become solidified in superimposed strata. These few sentences +describe the general character of the products of volcanic activity. + +p 234 +Rocks which are merely broken through by the volcanic action are often +inclosed in the igneous products. Thus i have found angular fragments of +feldspathic syenite imbedded in the black augitic lava of the volcano of +Jorullo, in Mexico; but the masses of dolomite and granular limestone, which +contain magnificent clusters of crystalling fossils (vesuvian and garnets, +covered with mejonite, nepheline, and sodalite), are not the ejected +products of Vesuvius, these belonging rather to very generally distributed +formations, viz., strata of tufa, which are more ancient than the elevation +of the Somma and of Vesuvius, and are probably the products of a deep-seated +and concealed submarine volcanic action.* + + +[footnote] *Leop. von Buch, in Poggend., 'Annalen', bd. xxxvii., s. 179. + + +We find five metals among the products of existing volcanoes, iron, copper, +lead, arsenic, and selenium, discovered by Stromeyer in the crater of +Volcano.* + + +[footnote] *[The little island of Volcano is separated from Lipari by a +narrow channel. It appears to have exhibited strong signs of volcanic +activity long before the Christian era, and still emits gaseous exhalations. + Stromeyer detected the presence of selenium in a mixture of sal ammoniac +and sulphur. Another product, supposed to be peculiar to this volcano, is +boracic acid, which lines the sides of the cavities in beautiful white silky +crystals. Daubeney, op. cit., p. 257.] -- Tr. + + +The vapors that rise from the 'fumarolles' cause the sublimation of the +chlorids of iron, copper, lead, and ammonium; iron glanceI and chlorid of +sodium (the latter often in large quantities) fill the cavities of recent +lava streams and the fissures of the margin of the crater. + + +[footnote] *Regarding the chemical origin of iron glance in volcanic +masses, see Mitscherlich, in Poggend., 'Annalen', bd. xv., s. 630; and on +the liberation of hydrochloric acid in the crater, see Gay-Lussac, in the +'Annals de Chimique et de Physique', t. xxii., p. 423. + + +The mineral composition of lava differs according to the nature of the +crystalline rock of which the volcano is formed, the height of the point +where the eruption occurs, whether at the foot of the mountain or in the +neighborhood of the crater, and the condition of temperature of the +interior. Vitreous volcanic formations, obsidian, pearl-stone, and pumice, +are entirely wanting in some volcanoes, while in the case of others they +only proceed from the crater, or, at any rate, from very considerable +heights. These important and involved relations can only be explained by +very accurate crystallographic and chemical investigations. My +fellow-traveler in Siberia, Gustav Rose, and subsequently Hermann Abich, +have already been able, by their fortunate and ingenious researches, to +throw much light on the structural relations of the various kinds of +volcanic rocks. + +p 235 +The greater part of the ascending vapor is mere steam. When condensed, this +forms springs, as in Pantellaria,Iwhere they are used by the goatherds of +the island. + + +[footnote] *[Steam issues from many parts of this insular mountain, and +several hot springs gush forth from it, which form together a lake 6000 feet +in circumference. Daubeney, op. cit.] -- Tr. + + +On the morning of the 26th of October, 1822, a current was seen to flow from +a lateral fissure of the crater of Vesuvius, and was loong supposed to have +been boiling water; it was, however, shown, by Monticelli's accurate +investigations, to consist of dry ashes, which fell like sand, and of lava +pulverized by friction. The ashes, which sometimes darken the air for hours +and days together, and produce great injury to the vineyards and olive +groves by adhering to the leaves, indicate by their columnar ascent, +impelled by vapors, the termination of every great eqrthquake. This is the +magnificent phenomenon which Pliny the younger, in his celebrated letter to +Cornelius Tacitus, compares, in the case of Vesuvius, to the form of a lofty +and thickly-branched and foliaceous pine. That which is described as flames +in the eruption of scoriae, and the radiance of the glowing red clouds that +hover over the crater, can not be ascribed to the effect of hydrogen gas in +a state of combustion. They are rather reflections of light which issue +from molten masses, projected high in the air, and also reflections from the +burning depths, whence the glowing vapors ascend. We will not, however, +attempt to decide the nature of the flames, which are occasionally seen now, +as in the time of Strabo, to rise from the deep sea during the activity of +littoral volcanoes, or shortly before the elevation of a volcanic island. + +When the questions are asked, what is it that burns in the volcano? what +excites the heat, fuses together earths and metals, and imparts to lava +currents of thick layers a degree of heat that lasts for many years? it is +necessarily implied that volcanoes must be connected with the existence of +substances capable of maintaining combustion, like the beds of coal in +subterranean fires. + + +[footnote] *See the beautiful experiments on the cooling of masses of rock, +in Bischof's 'Warmelehre', s. 384, 443, 500-512. + + +According to the different phases of chemical science, bitumen, pyrites, the +moist admixture of finely-pulverized sulphur and iron, pyrophoric +substances, and the metals of the alkalies and earths, have in turn been +designated as the cause of intensely active volcanic phenomena. The great +chemist, Sir Humphrey Davy, to whom we are indebted for the knowledge of the +most combustible metallic +p 236 +substances, has himself renounced his bold chemical hypothesis in his last +work ('Consolation in Travel, and last Days of a Philosopher') -- a work +which can not fail to excite in the reader a feeling of the deepest +melancholy. the great mean density of the earth (5.44), when compared with +the specific weight of potassium (0.865), of sodium (-.972), or of the +metals of the earths (1.2), and the absence of hydrogen gas in the gaseous +emanations from the fissures of craters, and from still warm streams of +lava, besides many chemical considerations, stand in opposition with the +earlier conjectures of Davy and Ampere.* + + +[footnote] *See Berzelius and Wohler, in Poggend., 'Annalen', bd. i., s. +221, and bd. xi., s. 146; Gay-Lussac, in the 'Annals de Chimie', t. x., +xii., p. 422; and Bischof's 'Reasons against the Chemical Theory of +Volcanoes', in the English edition of his 'Warmelehre', p. 297-309. + + +If hydrogen were evolved from erupted lava, how great must be the quantity +of the gas disengaged, when, the seat of the volcanic activity being very +low, as in the case of the remarkable eruption at the foot of the Skaptar +Jokul in Iceland (from the 11th of June to the 3d of August, 1783, described +by Mackenzie and Soemund Magnussen), a space of many square miles was +covered by streams of lava, accumulated to the thickness of several hundred +feet! Similar difficulties are opposed to the assumption of the penetration +of the atmospheric air into the crater, or, as it is figuratively expressed, +the 'inhalation of the earth', when we have regard to the small quantity of +nitrogen emitted. So general, deep-seated, and far-propagated an activity +as that of volcanoes, can not assuredly have its source in chemical +affinity, or in the mere contact of individual or merely locally distributed +substances. Modern geognosy* rather seeks the cause of this activity in the +increased temperature with the increase of depth at all degrees of latitude, +in that powerful internal heat which our planet owes to its first +solidification, its formation in the regions of space, and to the spherical +contraction of +p 237 +matter revolving elliptically in a gaseous condition. + + +[footnote] *[On the various theories that have been advanced in explanation +of volcanic action, see Daubeney 'On Volcanoes', a work to which we have +made continual reference during the preceding pages, as it constitutes the +most recent and perfect compendium of all the important facts relating to +this subject, and is peculiarly adapted to serve as a source of reference to +the 'Cosmos', since the learned author in many instances enters into a full +exposition of the views advanced by Baron Humboldt. The appendix contains +several valuable notes with reference to the most recent works that have +appeared on the Continent, on subjects relating to volcanoes; among others, +an interesting notice of Professor Bischof's views "on the origin of the +carbonic acid discharged from volcanoes," as enounced in his recently +published work, 'Lehrbuch der Chemischen und Physikalischen Geologie'.] -- +Tr. + + +We have thus mere conjecture and supposition side by side with certain +knowledge. A philosophical study of nature strives ever to elevate itself +above the narrow requirements of mere natural description, and does not +consist, as we have already remarked, in the mere accumulation of isolated +facts. The inquiring and active spirit of man must be suffered to pass from +the present to the past, to conjecture all that can not yet be known with +certainty, and still to dwell with pleasure on the ancient myths of geognosy +which are presented to us under so many various forms. If we consider +volcanoes as irregular intermittent springs, emitting a fluid mixture of +oxydized metals, alkalies, and earths, flowing gently and calmy wherever +then find a passage, or being upheaved by the powerful expansive force of +vapors, we are involuntarily led to remember the geognostic visions of +Plato, according to which hot springs, as well as all volcanic igneous +streams, were eruptions that might be traced back to one generally +distributed subterranean cause, 'Pyriphlegethon'.* + + +[footnote] *According to Plato's geognostic views, as developed in the +'Phaedo', Pyriphlegethon plays much the same part in relation to the +activity of volcanoes that we now ascribe to the augmentation of heat as we +descend from the earth's surface, and to the fused condition of its internal +strata. ('Phaedo', ed. Ast, p. 603 and 607; Annot., p. 308 and 817.) +"Within the earth, and all around it, are larger and smaller caverns. Water +flows there in abundance; also much fire and large streams of fire, and +streams of moist mud (some purer and others more filthy), like those in +Sicily, consisting of mud and fire, preceding the great eruption. These +streams fill all places that fall in the way of their course. +Pyriphlegethon flows forth into an extensive district burning with a fierce +fire, where it forms a lake larger than our sea, boiling with water and mud. + From thence it moves in circles round the earth, turbid and muddy." This +stream of molten earth and mud is so much the general cause of volcanic +phenomena, that Plato expressly adds, "thus is Pyriphlegethon constituted, +from which also the streams of fire ([Greek words]), wherever they reach the +earth ([Greek words]), inflate such parts (detached fragments)." Volcanic +scoriae and lava streams are therefore portions of Pyriphlegethon itself, +portions of the subterranean molten and ever-undulating mass. That {Greek +words] are lava streams, and not, as Schneider, Passow, and Schleiermacher +will have it, "fire-vomiting mountains," is clear enough from many passages, +some of which have been collected by Ukert ('Geogr. der Griechen und Romer', +th. ii., s. 200): [Greek word] is the volcanic phenomenon in reference to +its most striking characteristic, the lava stream. Hence the expression, the +[Greek word] of Aetna. Aristot. 'Mirab. Ausc.', t. ii., p. 833; sect. 38, +Bekker; Thucyd., iii., 116; Theophrast., 'De Lap'., 22, p. 427, Schneider; +Diod., v., 6, and xiv., 59, where are the remarkable words, "Many places +near the sea, in the neighborhood of Aetna, were leveled to the ground, +[Greek words];" Strabo, vi., p. 269; xiii., p. 268, and where there is a +notice of the celebrated burning mud of the Lelantine plains, in Euboea, i., +p. 58, Casaub.; and Appian, 'De Bello Civili', v., 114. The blame which +Aristotle throws on the geognostical fantasies of the Phaedo ('Meteor.', +ii., 2, 19) is especially applied to the sources of the rivers flowing over +the earth's surface. The distinct statement of Plato, that "in Sicily +eruptions of wet mud precede the glowing (lava) stream," is very remarkable. + Observations on Aetna could not have led to such a statement, unless pumice +and ashes, formed into a mud-like mass by admixture with melted snow and +water, during the volcano-electric storm in the crater of eruption, were +mistaken for ejected mud. It is more probable that Plato's streams of moist +mud ([Greek words]) originated in a faint recollection of the salses (mud +volcanoes) of Agrigentum, which, as I have already mentioned, eject +argillaceous mud with a loud noise. It is much to be regretted, in +reference to this subject, that the work of Theophrastus [Greek words] 'On +the Volcanic Stream in Sicily', to which Diog. Laert., v., 49, refers, has +not come down to us. + + +p 238 +The different volcanoes over the earth's surface, when they are considered +independently of all climatic differences, are acutely and +characteristically classified as central and linear volcanoes. Under the +first name are comprised those which constitute the central point of many +active mouths of eruption, distributed almost regularly in all directions; +under the second, those lying at some little distance from one another, +forming, as it were, chimneys or vents along an extended fissure. Linear +volcanoes again admit of further subdivision, namely, those which rise like +separate conical islands from the bottom of the sea, being generally +parallel with a chain of primitive mountains, whose foot they appear to +indicate, and those volcanic chains which are elevated on the highest ridges +of these mountain chains, of which they form the summits.* + + +[footnote] *Leopold von Buch, 'Physikal. Beschreib. der Canarischen +Inseln', s. 326-407. I doubt if we can agree with the ingenious Charles +Darwin ('Geological Observations on Volcanic Islands', 1844, p. 127) in +regarding central volcanoes in general as volcanic chains of small extent on +parallel fissures. Friedrich Hoffman believes that in the group of the +Lipari Islands, which he has so admirably described, and in which two +eruption fissures intersect near Panaria, he has found an intermediate link +between the two principal modes in which volcanoes appear, namely, the +central volcanoes and volcanic chains of Von Buch (Poggendorf, 'Annalen der +Physik', bd. xxvi., s. 81-88). + + +The Peak of Teneriffe, for instance, is a central volcano, being the central +point of the volcanic group to which the eruption of Palma and Landerote may +be referred. The long, rampart-like chain of the Andes, which is sometimes +single, and sometimes divided into two or three parallel branches, connected +by various transverse ridges, presents, from the south of Chili to the +northwest coast of America, one of the grandest instances of a continental +volcanic chain. The proxiimity of +p 239 +active volcanoes is always manifested in the chain of the Andes by the +appearance of certain rocks (as dolerite, melaphyre, trachyte, andesite, and +dioritic porphyry), which divide the so-called primitive rocks, the +transition slates and sandstones, and the stratified formations. the +constant recurrence of this phenomenon convinced me long since that these +sporadic rocks were the seat of volcanic phenomena, and were connected with +volcanic eruptions. At the foot of the grand Tunguragua, near Penipe, on +the banks of the Rio Puela, I first distinctly observed mica slate resting +on granite, broken through by a volcanic rock. + +In the volcanic chain of the New Continent, the separate volcanoes are +occasionally, when near together in mutual dependence upon one another; and +it is even seen that the volcanic activity for centuries together has moved +on in one and the same direction, as for instance, from north to south in +the province of Quito.* + + +[footnote] (Humboldt, 'Geognost. Beobach, uber die Vulkane des Hochlandes +von Quito', in Poggend., 'Annal. der Physik', bd. xliv., s. 194. + + +The focus of the volcanic action lies below the whole of the highlands of +this province; the only channels of communication with the atmosphere are, +however, those mountains which we designate by special names, as the +mountains of Pichincha, Cotopaxi, and Tunguragua, and which, from their +grouping, elevation, and form, constitute the grandest and most picturesque +spectacle to be found in any volcanic district of an equally limited extent. + Experience shows us, in many instances, that the extremities of such groups +of volcanic chains are connected together by subterranean communications; +and this fact reminds us of the ancient and true expression made use of by +Seneca,* that the igneous mountain is only the issue of the more +deeply-seated volcanic forces. + + +[footnote] *Seneca, while he speaks very clearly regarding the +problematical sinking of Aetna, says in his 79th letter, "Though this might +happen, not because the mountain's height is lowered, but because the fires +are weakened, and do not blaze out with their former vehemence; and for +which reason it is that such vast clouds of smoke are not seen in the +day-time. Yet neither of these seem incredible, for the mountain may +possibly be consumed by being daily devoured, and the fire not be so large +as formerly, since it is not self-generated here, but is kindled in the +distant bowels of the earth, and there rages, being fed with continual fuel, +not with that of the mountain, through which it only makes its passage." +The subterranean communication, "by galleries," between the volcanoes of +Sicily, Lipari, Pithecusa (Ischia), and Vesuvius, "of the last of which we +may conjecture that it formerly burned and presented a fiery circle," seems +fully understood by Strabl (lib. i., p. 247 and 248). He terms the whole +district "sub-igneous." + + +In the Mexican highlands a mutual dependence is +p 240 +also observed to exist among the volcanic mountains Orizaba, Popocatepel, +Jorullo, and Colima; and I have shown* that they all lie in one direction +between 18 degrees 59' and 19 degrees 12' north latitude, and are situated +in a transverse fissure running from sea to sea. + + +[footnote] *Humboldt, 'Essai Politique sur la Nouv. Espagne', t. ii., p. +173-175. + + +The volcano of Jorullo broke forth on the 29th of September, 1759, exactly +in this direction, and over the same transverse fissure, being elevated to a +height of 1604 feet above the level of the surrounding plain. The mountain +only once emitted an eruption of lava, in the same manner as is recorded of +Mount Epomeo in Ischia, in the year 1302. But although Jorullo, which is +eighty miles from any active volcano, is in the strict sense of the word a +new mountain, it must not be compared with Monte Nuovo, near Puzzuolo, which +first appeared on the 19th of September, 1538, and is rather to be classed +among craters of elevation. I believe that I have furnished a more natural +explanation of the eruption of the Mexican volcano, in comparing its +appearance to the elevation of the Hill of Methone, now Methana, in the +peninsula of Troezene. The description given by Strabo and Pausanias of +this elevation, led one of the Roman poets, most celebrated for his richness +of fancy, to develop views which agree in a remarkable manner with the +theory of modern geognosy. "Near Troezene is a tumulus, steep and devoid of +trees, once a plain, now a mountain. The vapors inclosed in dark caverns in +vain seek a passage by which they may escape. The heavier earth, inflated +by the force of the compressed vapors, expands like a bladder filled with +air, or like a goat-skin. The ground has remained thus inflated, and the +high projecting eminence has been solidified by time into a naked rock." +Thus picturesquely, and, as analogous phenomena justify us in believing, +thus truly has Ovid described that great natural phenomenon which occurred +282 years before our era, and consequently, 45 years bfore the volcanic +separation of Thera (Santorino) and Therasia, between Troezene and +Epidaurus, on the same spot where Russegger has found veins of trachyte.* + + +[footnote] *Ovid's description of the eruption of Methone ('Metam.', xv., +p. 226-306): +"Near Troezene stands a hill, exposed in air +To winter winds, of leafy shadows bare: +This once was level ground; but (strange to tell) +Th' included vapors, that in caverns dwell, +Laboring with colic pangs, and close confined, +In vain sought issue for the rumbling wind: +Yet still they heaved for vent, and heaving still, +Enlarged the concave and shot up the hill, +As breath extends a bladder, or the skins +Of goats are blown t'inclose the hoarded wines; +The mountain yet retains a mountain's face, +And gathered rubbish heads the hollow space." + 'Dryden's Translation'. +[footnote continues] +This description of a dome-shaped elevation on the continent is of great +importance in a geognostical point of view, and coincides to a remarkable +degree with Aristotle's account ('Meteor.', ii., 89, 17-19) of the upheaval +of islands of eruption: "The heaving of the earth does not cease till the +wind [(Greek word)] which occasions the shocks has made its escape into the +crust of the earth. It is not long ago since this actually happened at +Heraclea in Pontus, and a similar event formerly occurred at Hiera, one of +the Aeolian Islands. A portion of the earth swelled up, and with loud noise +rose into the form of a hill, till the mighty urging blast [(Greek word)] +found an outlet, and ejected sparks and ashes which covered the neighborhood +of Lipari, and even extended to several Italian cities." In this +description, the vesicular distension of the earth's crust (a stage at which +many trachytic mountains have remained) is very well distinguished from the +eruption itself. Strabo, lib. i., p. 59 (Casaubon), likewise describes the +phenomenon as it occurred at Methone: near the town, in the Bay of +Hermione, there arose a flaming eruption; a fiery mountain, seven (?) stadia +in height, was then thrown up, which during the day was inaccessible from +its heat and sulphureous stench, but at night evolved an agreeable odor (?) +, and was so hot that the sea boiled for a distance of five stadia, and was +turbid for full twenty stadia, and also was filled with detached masses of +rock. Regarding the present mineralogical character of the peninsula of +Methana, see Fiedler, 'Reise durch Griechenland', th. i., s. 257-263. + + +p 241 +Santorino is the most important of all the 'islands of eruption' belonging +to volcanic chains.* + + +[footnote] *[I am indebted to the kindness of Professor E. Forbes for the +following interesting account of the island of Santorino, and the adjacent +islands of Neokaimeni and Microkaimeni. "The aspect of the bay is that of a +great crater filled with water, Thera and Therasia forming its walls, and +the other islands being after-productions in its center. We sounded with +250 fathoms of line in the middle of the bay, between Therasia and the main +islands, but got no bottom. Both these islands appear to be similarly +formed of successive strata of volcanic ashes, which, being of the most +vivid and variegated colors, present a striking contrast to the black and +cindery aspect of the central isles. Neokaimeni, the last-formed island, is +a great heap of obsidian and scoriae. So, also, is the greater mass, +Microkaimeni, which rises up in a conical form, and has a cavity or crater. +On one side of this island, however, a section is exposed, and cliffs of +fine pumiceous ash appear stratified in the greater islands. In the main +island, the volcanic strata abut against the limestone mass of Mount St. +Elias in such a way as to lead to the inference that they were deposited in +a sea bottom in which the present mountain rose as a submarine mass of rock. + The people at Santorino assured us that subterranean noises are not +unfrequently heard, especially during calms and south winds, when they say +the water of parts of the bay becomes the color of sulphur. My own +impression is, that this group of islands, constitutes a crater of +elevation, of which the outer ones are the remains of the walls, while the +central group are of later origin, and consist partly of upheaved sea +bottoms and partly of erupted matter -- erupted, however, beneath the +surface of the water."] -- Tr. + + +It combines within itself +p 242 +the history of all islands of elevation. For upward of 2000 years, as far +as history and tradition certify, it would appear as if nature were striving +to form a volcano in the midst of the crater of elevation."* + + +[footnote] *Leop. von Buch, 'Physik. Beschr. der Canar. Inseln', s. +356-358, and particularly the French translation of this excellent work, p. +402; and his memoir in Poggendorf's 'Annalen', bd. xxxviii., s. 183. A +submarine island has quite recently made its appearance within the crater of +Santorino. In 1810 it was still fifteen fathoms below the surface of the +sea, but in 1830 it had risen to within three or four. It rises steeply +like a great cone, from the bottom of the sea, and the continuous activity +of the submarine crater is obvious from the circumstance that sulphurous +acid vapors are mixed with the sea water, in the eastern bay of Neokaimeni, +in the same manner as at Vromolimni, near Methana. Coppered ships lie at +anchor in the bay in order to get their bottoms cleaned and polished by this +natural (volcanic) process. (Virlet, in the 'Bulletin de la Societe +Geologique de France', t. iii., p. 109, and Fiedler 'Reise durch +Griechenland', th. ii., s. 469 and 584.) + + +Similar insular elevations, and almost always at regular intervals of 80 or +90 years,* have been manifested in the island of St. Michael, in the Azores; +but in this case the bottom of the sea has not been elevated at exactly the +same parts.** + + +[footnote] *Appearance of a new island near St. Miguel, one of the Azores, +11th of June, 1638, 31st of December, 1719, 13th of June, 1811. + + +[footnote] **[My esteemed friend, Dr. Webster, professor of Chemistry and +Mineralogy at Harvard College, Cambridge, Massachusetts, U. S., in his +'Description of the Island of St. Michael, etc.', Boston, 1822, gives an +interesting account of the sudden appearance of the island named Sabrina +which was about a mile in circumference, and two or three hundred feet above +the level of the ocean. After continuing for some weeks, it sank into the +sea. Dr. Webster describes the whole of the island of St. Michael as +volcanic, and containing a number of conical hills of trachyte, several of +which have craters, and appear at some former time to have been the openings +of volcanoes. The hot springs which abound in the island are impregnated +with sulphureted hydrogen and carbonic acid gases, appearing to attest the +existence of volcanic action.] -- Tr. + + +The island which Captain Tillard named 'Sabrina', appeared unfortunately at +a time (the 30th of January, 1811) when the political relations of the +maritime nations of Western Europe prevented that attention being bestowed +upon the subject by scientific institutions which was afterward directed to +the sudden appearance (the 2d of July, 1831), and the speedy destruction of +the igneous island of Ferdinandea in the Sicilian Sea, between the limestone +shores of Sciacca and the purely volcanic island of Pantellaria.* + + +[footnote] *Prevost, in the Bulletin de la Societe Geologique, t. iii., p. +34; Friedrich Hoffman, 'Hinterlassene Werke.' bd. ii., s. 451-456. + + +p 243 +The geographical distribution of the volcanoes which have been in a state of +activity during historical times, the great number of insular and littoral +volcanic mountains, and the occasional, although ephemeral, eruptions in the +bottom of the sea, early led to the belief that volcanic activity was +connected with the neighborhood of the sea, and was dependent upon it for +its continuance. "For many hundred years," says Justinian, or rather Trogus +Pompeius, whom he follows,* "Aetna and the Aeolian Islands have been +burning, and how could this have continued so long if the fire had not been +fed by the +p 244 +neighboring sea?"** + + +[footnote] *"Accedunt vicini et perpetui Aetnae montis ignes et insularum +Aeolidum, veluti ipsis undis alatur incendium; neque enim aliter durare tot +seculis tantus ignis potuisset, nisi humoris nutrimentis aleretur." +(Justin, 'Hist. Philipp.', iv., i.) The volcanic theory with which the +physical description of Sicily here begins is extremely intricate. Deep +fissured; violent motion of the waves of the sea, which, as they strike +together, draw down the air (the wind) for the maintenance of the fire: +such are the elements of the theory of Trogus. Since he seems from Pliny +(xi., 52) to have been a physiognomist, we may presume that his numerous +lost works were not confined to history alone. The opinion that air is +forced into the interior of the earth, there to act on the vocanic furnaces, +was connected by the ancients with the supposed influence of winds from +different quarters on the intensity of the fires burning in tna, Hiera, and +Stromboli. (See the remarkable passage in Strabo, liv. vi., Aetna.) The +mountain island of Stromboli (Strongyle) was regarded therefore, as the +dwelling-place of Aeolus, "the regulator of the winds," in consequence of +the sailors foretelling the weather from the activity of the volcanic +eruptions of this island. The connection between the eruption of a small +volcano with the state of the barometer and the direction of the wind is +still generally recognized (Leop. von Buch, 'Descr. Phys. des Iles +Canaries', p. 334; Hoffmann, in Poggend., 'Annalen', bd. xxvi., s. viii), +although our present knowledge of volcanic phenomena, and the slight changes +of atmospheric pressure accompanying our winds, do not enable us to offer +any satisfactory explanation of the fact. Bembo, who during his youth was +brought up in Sicily by Greek refugees, gave an agreeable narrative of his +wanderings, and in his 'Aetna Dialogus' (written in the middle of the +sixteenth century) advances the theory of the penetration of sea water to +the very center of the volcanic action, and of the necessity of the +proximity of the sea to active volcanoes. In ascending Aetna the following +question was proposed: "Explaina potius nobis quae petimus, ea incendia +unde oriantur et orta quomodo perdurent. In omni tellure nuspiam majores +fistulae aut meatus ampliores sunt quam in locis, quae vel mari vicina sunt, +vel a mari protinus alluntur: mare erodit illa facillime pergitque in +viscera terrae. Itaque cum in aliena regna sibi viam faciat, ventis etiam +facit; ex quo fit, ut loca quaeque maritima maxime terrae motibus subjecta +sint, parum mediterranea. Habes quum in sulfuris venas venti furentes +inciderint, unde incendia oriantur tn tuae. Vides, quae mare in radicibus +habeat, quae sulfurea sit, quae cavernosa, quae a mari aliquando perforata +ventos admiscrit Aestuantes, per quos idonea flammae materies incenderetur." + +[footnote] **[Although extinct volcanoes seem by no means confined to the +neighborhood of the present seas, being often scattered over the most inland +portions of our existing continents, yet it will appear that, at the time at +which they were in an active state, the greater part were in the +neighborhood either of the sea, or of the extensive salt or fresh water +lakes, which existed at that period over much of what is now dry land. This +may be seen either by referring to Dr. Boue's map of Europe, or to that +published by Mr. Lyell in the recent edition of his 'Principles of Geology' +(1847), from both of which it will become apparent that, at a comparatively +recent epoch, those parts of France, of Germany, of Hungary, and of Italy, +which afford evidences of volcanic action now extinct, were covered by the +ocean. Daubeney 'On Volcanoes', p. 605.] -- Tr. + + +In order to explain the necessity of the vicinity of the sea, recourse has +been had, even in modern times, to the hypothesis of the penetration of sea +water into the foci of volcanic agency, that is to say, into deep-seated +terrestrial strata. When I collect together all the facts that may be +derived from my own observation and the laborious researches of others, it +appears to me that every thing in this great quantity of aqueous vapors, +which are unquestionably exhaled from volcanoes even when in a state of +rest, be derived from sea water impregnated with salt, or rather, perhaps +with fresh meteoric water; or whether the expansive force of the vapors +(which, at a depth of nearly 94,000 feet, is equal to 2800 atmospheres) +would be able at different depths to counterbalance the hydrostatic pressure +of the sea, and thus afford them, under certain conditions, a free access to +the focus;* or whether the formation of metallic chlorids, the presence of +chlorid of sodium in the fissures of the crater, and the frequent mixture of +hydrochloric acid with the aqueous vapors, necessarily imply access of sea +water; or, finally, whether the repose of volcanoes (either when temporary, +or permanent and complete) depends upon the closure of the channels by which +the sea or meteoric water was conveyed, or whether the absence of flames and +of exhalations of hydrogen (and sulphureted hydrogen gas seems more +characteristic of solfataras than of active volcanoes) is not directly at +variance +p 245 +with the hypothesis of the decomposition of great masses of water?** + + +[footnote] * Compare Gay-Lussac, 'Sur les Volcans', in the 'Annales de +Chimie', t. xxii., p. 427, and Bischof, 'Warmelehre', s. 272. The eruptions +of smoke and steam which have at different periods been seen in Lancerote, +Iceland, and the Kurile Islands, during the eruption of the neighboring +volcanoes, afford indications of the reaction of volcanic foci through tense +columns of water; that is to say, these phenomena occur when the expansive +force of the vapor exceeds the hydrostatic pressure. + +[footnote] ** [See Daubeney 'On Volcanoes', Part iii., ch. xxxvi., +xxxviii., xxxix.] -- Tr. + + +The discussion of these important physical questions does not come within +the scope of a work of this nature; but, while we are considering these +phenomena, we would enter somewhat more into the question of the +geographical distribution of still active volcanoes. We find, for instance, +that in the New World, three, viz., Jorullo, Popocatepetl, and the volcano +of De la Fragua, are situated at the respective distances of 80, 132, and +196 miles from the sea-coast, while in Central Asia, as Abel Remusat* first +made known to geognosists, the Thianschan (Celestial Mountains), in which +are situated the lava-emitting mountain of Pe-schan, the solfatara of +Urumtsi, and the still active igneous mountain (Ho-tscheu) of Turfan, lie at +an almost equal distance (1480 to 1528 miles) from the shores of the Polar +Sea and those of the Indian Ocean. + + +[footnote] *Abel Remusat, 'Lettre a M. Cordier', in the 'Annales de +Chimie', t. v., p. 137. + + +Pe-schan is also fully 1360 miles distant from the Caspian Sea,* and 172 and +218 miles from the seas of Issikul and Balkasch. + + +[footnote] *Humboldt, 'Asie Centrale', t. ii., p. 30-33, 38-52, 70-80, and +426-428. The existence of active volcanoes in Kordofan, 540 miles from the +Red Sea, has been recently contradicted by Ruppell, 'Reisen in Nubien', +1829, s. 151. + + +It is a fact worthy of notice, that among the four great parallel mountain +chains which traverse the Asiatic continent from east to west, the Altai, +the Thianschan, the Kuen-lun, and the Himalaya, it is not the latter chain, +which is nearest to Kuen-lun, at the distance of 1600 and 720 miles from the +sea, which have fire-emitting mountains like Aetna and Vesuvius, and +generate ammonia like the volcano of Guatimala. Chinese writers undoubtedly +speak of lava streams when they describe the emissions of smoke and flame, +which, issuing from Pe-schan, devastated a space measuring ten li* in the +first and seventh centuries of our era. + + +[footnote] *[A 'li' is a Chinese measurement, equal to about one thirtieth +of a mile.] -- Tr. + + +Burning masses of stone flowed, according to their description "like thin +melted fat." The facts that have been enumerated, and to which sufficient +attention has not been bestowed, render it probable that the vicinity of the +sea, and the penetration of sea water to the foci of volcanoes, are not +absolutely necessary to the eruption of +p 246 +subterranean fire, and that littoral situations only favor the eruption by +forming the margin of a deep sea basin, which, covered by strata of water, +and lying many thousand feet lower than the interior continent, can offer +but an inconsiderable degree of resistance. + +The present active volcanoes, which communicate by permanent craters +simultaneously with the interior of the earth and with the atmosphere, must +have been formed at a subsequent period, when the upper chalk strta and all +the tertiary formations were already present: this is shown to be the fact +by the trachytic and basaltic eruptions which frequently form the walls of +the crater of elevation. Melaphyres extend to the middle tertiary +formations, but are found already in the Jura limestone, where they break +through the variegated sandstone.* + + +[footnote] *Dufrenoy et Elie de Beaumont, 'Explication de la Carte +Geologique de la France', t. i., p. 89. + + +We must not confound the earlier outpourings of granite, quartzose porphyry, +and euphotide from temporary fissures in the old transition rocks with the +present active volcanic craters. + +The extinction of volcanic activity is either only partial -- in which case +the subterranean fire seeks another passage of escape in the same mountain +chain -- or it is total, as in Auvergne. More recent examples are recorded +in historical times, of the total extinction of the volcano of Mosychlos,* +on the island sacred to Hephaestos (Vulcan), whose "high whirling flames" +were known to Sophocles; and of the volcano of Medina, which according to +Burckhardt, still continued to pour out a stream of lava on the 2d of +November, 1276. + + +[footnote] *Sophocl., 'Philoct.', v. 971 and 972. On the supposed epoch of +the extinction of the Lemnian fire in the time of Alexander, compare +Buttmann, in the 'Museum der Alterhumswissenschaft', bd. i., 1807, s. 295; +Dureau de la Malle, in Malte-Brun, 'Annales des Voyages', t. ix., 1809, p. +5; Ukert in Bertuch, 'Geogr. Ephemeriden', bd. xxxix., 1812, s. 361; Rhode, +'Res Lemnicae', 1829, p. 8; and Walter, 'Ueber Abnahame der Vulken. +Thatigkeit in Historischen Zeiten', 1844, s. 24. The chart of Lemmos, +constructed by Choiseul, makes it extremely probable that the extinct crater +of Mosychlos, and the island of Chryse, the desert habitation of Philoctetes +(Otfried Muller, 'Minyer', s. 300), have been long swallowed up by the sea. +Reefs and shoals, to the northeast of Lemnos, still indicate the spot where +the Aegean Sea once possessed an active volcano like Aetna, Vesuvius, +Stromboli, and Volcano (in the Lipari Isles). + + +Every stage of volcanic activity, from its first origin to its extinction, +is characterized by peculiar products; first by ignited scoriae, streams of +lava consisting of trachyte, pyroxene, and obsidian, and by rapilli and +tufaceous ashes, accompanied by the development +p 247 +of large quantities of pure aqueous vapor; subsequently, when the volcano +becomes a solfatara, by aqueous vapors mixed with sulphureted hydrogen and +carbonic acid gases; and, finally, when it is completely cooled, by +exhalations of carbonic acid alone. There is a remarkable class of igneous +mountains which do not eject lava, but merely devastating streams of hot +water,* impregnated with burning sulphur and rocks reduced to a state of +dust (as, for instance, the Galungung in Java); but whether these mountains +present a normal condition, or only a certain transitory modification of the +volcanic process, must remain undecided until they are visited by geologists +possessed of a knowledge of chemistry in its present condition. + + +[footnote] *Compare Reinwardt and Hoffmann, in Poggendorf's 'Annalen', bd. +xii., s. 607; Leop. von Buch, 'Descr. des Iles Canaries', p. 424-426. The +eruptions of argillaceous mud at Carguairazo, when that volcano was +destroyed in 1698, the Lodazales of Igualata, and the Moya of Pelileo -- all +on the table-land of Quito -- are volcanic phenomena of a similar nature. + + +I have endeavored in the above remarks to furnish a general description of +volcanoes -- comprising one of the most important sections of the history of +terrestrial activity -- and I have based my statements partly on my own +observations, but more in their general bearing on the results yielded by +the labors of my old friend, Leopold von Buch, the greatest geognosist of +our own age, and the first who recognized the intimate connection of +volcanic phenomena, and their mutual dependence upon one another, considered +with reference to their relations in space. + +Volcanic action, or the reaction of the interior of a planet on its external +crust and surface, was long regarded only as an isolated phenomenon, and was +considered solely with respect to the disturbing action of the subterranean +force; and it is only in recent times that -- greatly to the advantage of +geognostical views based on physical analogies -- volcanic forces have been +regarded as 'forming new rocks, and transforming those that already +existed'. We here arrive at the point to which I have already alluded, at +which a well-grounded study of the activity of volcanoes, whether igneous or +merely such as emit gaseous exhalations, leads us, on the one hand, to the +mineralogical branch of geognosy (the science of the texture and the +succession of terrestrial strata), and, on the other, to the science of +geographical forms and outlines -- the configuration of continents and +insular groups elevated above the level +p 248 +of the sea. This extended insight into the connection of natural phenomena +is the result of the philosophical direction which has been so generally +assumed by the more earnest study of geognosy. Increased cultivation of +science and enlargement of political views alike tend to unite elements that +had long been divided. + +This material taken from pages 248- + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p 248 + +If, instead of classifying rocks according to their varieties of form and +superposition into stratified and unstratified, schistose and compact, +normal and abnormal, we investigate those phenomena of formation and +transformation which are still going on before our eyes, we shall find that +rocks admit of being arranged according to four modes of origin. + +'Rocks of eruption', which have issued from the interior of the earth either +in a state of fusion from volcanic action, or in a more or less soft, +viscous condition, from Plutonic action. + +'Sedimentary rocks', which have been precipitated and deposited on the +earth's surface from a fluid, in which the most minute particles were either +dissolved or held in suspension constituting the greater part of the +secondary (or flotz) and tertiary groups. + +'Transformed or metamorphic rocks',* in which the internal texture and the +mode of stratification have been changed, either +p 249 +by contact or proximity with a Plutonic or volcanic endogenous rock of +eruption,** or, what is more frequently the case, by a gaseous sublimation +of substances*** which accompany certain masses erupted in a hot, fluid +condition. + + +[footnote] *[As the doctrine of mineral metamorphism is now exciting very +general attention, we subjoin a few explanatory observations by the 'New +Philos. Journ.', Jan., 1848: "In its widest sense, mineral metamorphism +means every change of aggregation, structure, or chemical condition which +rocks have undergone subsequently to their deposition and stratification, or +the effects which have been produced by other forces than gravity and +cohesion. There fall under this definition, the discoloration of the +surface of black limestone by the loss of carbon; the formation of +brownish-red crusts on rocks of limestone, sandstone, many slate structures, +serpentine, granite, etc., by the decomposition of iton pyrites, or magnetic +iron, finely disseminated in the mass of the rock; the conversion of +anhydrite into gypsum, in consequence of the absorption of water; the +crumbling of many granites and porphyries into gravel, occasioned by the +decomposition of the mica and feldspar. In its more limited sense, the term +metamorphic is confined to those changes of the rock which are produced, not +by the effect of the atmosphere or of water on the exposed surfaces, but +which are produced, directly or indirectly, by agencies seated in the +interior of the earth. In many cases the mode of change may be explained by +our physical or chemical theories, and may be viewed as the effect of +temperature or of electro-chemical actions. Adjoining rocks, or connecting +communications with the interior of the earth, also distinctly point out the +seat from which the change proceeds. In many other cases the metamorphic +process itself remains a mystery, and from the nature of the products alone +do we conclude that such a metamorphic action has taken place.] -- Tr. + + +[footnote] ** In a plan of the neighborhood of Tezcuco, Totonilco, and +Moran ('Atlas Geographique et Physique', pl. vii.), which I originally +(1803) intended for a work which I never published, entitled 'Pasigrafia +Geognostica destinada al uso de los Jovenes del Colegio de Mineria de +Mexico', I names (in 1832) the Plutonic and volcanic eruptive rocks +'endogenous' (generated in the interior), and the sedimentary and flotz +rocks 'exogenous' (or generated externally on the surface of the earth). +Pasiward, [upward arrow] and the latter by the same symbol directed downward +[downward arrow]. These signs have at least some advantage over the +ascending lines, which in the older systems represent arbitrarily and +ungracefully the horizontally ranged sedimentary strata, and their +penetration through masses of basalt, porphyry, and syenite. The names +proposed in the pasigraphico-geognostic plan were borrowed from De +Candolle's nomenclature, in which 'endogenous' is synonymous with +monocotyledonous, and 'exogenous' with dicotyledonous plants. Mohl's more +accurate examination of vegetable tissues has, however, shown that the +growth of monocotyledons from within, and dicotyledons from without, is not +strictly and generally true for vegetable organisms (Link, 'Elementa +Philosophiae Botanicae', t. i., 1837, p. 287; Endlicher and Unger, +'Grundzugeder Botanik', 1843, s. 89; and Jussieu, 'Traite de Botanique', t. +i., p. 85). The rocks which I have termed endogenous are characteristically +distinguished by Lyell, in his 'Principles of Geology', 1833, vol. iii., p. +374, as "nether-formed" or "hypogene rocks." + + +[footnote] *** Compare Leop. von Buch, 'Ueber Dolomit als Gebirgsart', 1823, +s. 36; and his remarks on the degree of fluidity to be ascribed to Plutonic +rocks at the period of their eruption, as well as on the formation of gneiss +from schist, through the action of granite and of the substances upheaved +with it, to be found in the 'Abhandl. der Akad. der Wissensch. zu Berlin' +for the year 1842, s. 58 und 63, and in the 'Jahrbuch fur Wissenschaftliche +Kritik', 1840, s. 195. + + +'Conglomerates'; coarse or finely granular sandstones, or breccias composed +of mechanically-divided masses of the three previous species. + +These four modes of formation -- by the emission of volcanic masses, as +narrow lava streams; by the action of these masses on rocks previously +hardened; by mechanical separation or chemical precipitation from liquids +impregnated with carbonic acid; and, finally, by the cementation of +disintegrated rocks of heterogeneous nature -- are phenomena and formative +processes which must merely be regarded as a faint reflection of that more +energetic activity which must have characterized the chaotic condition of +the earlier world under wholly different conditions of pressure and at a +higher temperature, not only in the whole crust of the earth, but likewise +in the more +p 250 +extended atmosphere, overloaded with vapors. The vast fissures which were +formerly open in the solid crust of the earth have since been filled up or +closed by the protrusion of elevated mountain chains, or by the penetration +of veins of rocks of eruption (granite, porphyry, basalt, and melaphyre); +and while, scarcely more than four volcanoes remaining through which fire +and stones are erupted, the thinner, more fissured, and unstable crust of +the earth was anciently almost every where covered by channels of +communication between the fused interior and the external atmosphere. +Gaseous emanations rising from very unequal depths, and therefore conveying +substances differing in their chemical nature, imparted greater activity to +the Plutonic processes of formation and transformation. The sedimentary +formations, the deposits of liquid fluids from cold and hot springs, which +we daily see producing the travertine strata near Rome, and near Hobart Town +in Van Diemen's Land, afford but a faint idea of the flotz formation. In +our seas, small banks of limestone, almost equal in hardness at some parts +to Carrara marble,* are in the course of formation, by gradual +precipitation, accumulation, and cementation -- processes whose mode of +action has not been sufficiently well investigated. + + +[footnote] Darwin, 'Volcanic Islands', 1844, p. 49 and 154. + + +The Sicilian coast, the island of Ascension, and King George's Sound in +Australia, are instances of this mode of formation. On the coasts of the +Antilles, these formations of the present ocean contain articles of pottery, +and other objects of human industry, and in Guadaloupe even human skeletons +of the Carib tribes.* + + +[footnote] *[In most instances the bones are dispersed; but a large slab of +rock, in which considerable portion of the skeleton of a female is embedded, +is preserved in the British Museum. The presence of these bones has been +explained by the circumstance of a battle, and the massacre of a tribe of +Gallibis by the Caribs, which took place near the spot in which they are +found, about 120 years ago; for, as the bodies of the slain were interred on +the sea-shore, their skeletons may have been subsequently covered by +sand-drift, which has since consolidated into limestone. Dr. Moultrie, of +the Medical College, Charleston, South Carolina, U.S., is, however, of +opinion that these bones did not belong to individuals of the Carib tribe, +but of the Peruvian race, or of a tribe possessing a similar craniological +development.] --Tr. + + +The negroes of the French colonies designate these formations by the name of +'Maconne-bon-Dieu'.* + + +Moreau de Jonnes, 'Hist. Phys. des Antilles', t. i., p. 136, 138, and 543; +Humboldt, 'Relation Historique', t. iii., p. 367. + + +A small colitic bed, formed in Lancerote, one of the Canary Islands, and +which, notwithstanding +p 251 +its recent formation, bears a resemblance to Jura Limestone, has been +recognized as a product of the sea and of tempests.* + + +[footnote] *Near Teguiza. Leop. von Buch, 'Canarische Inseln', s. 301. + + +Composite rocks are definite associations of certain crytonostic, simple +minerals, as feldspar, mica, solid silex, augite, and nepheline. Rocks very +similar to these consisting of the same elements, but grouped differently, +are still formed by volcanic processes, as in the earlier periods of the +world. The character of rocks, as we have already remarked is so +independent of geographical relations of space,* that the geologist +recognizes with surprise, alike to the north or the south of the equator, in +the remotest and most dissimilar zones, the familiar aspect, and the +repetition of even the most minute characteristics in the periodic +stratification of the silurian strata, and in the effects of contact with +augitic masses of eruption. + + +[footnote] *Leop. von Buch, op. cit., p. 9. + + +We will now enter more fully into the consideration of the four modes in +which rocks are formed -- the four phases of their formative processes +manifested in the stratified and unstratified portions of the earth's +surface; thus, in the 'endogenous' or 'erupted rocks', designated by modern +geognosists as compact and abnormal rocks, we may enumerate the following +principal groups as immediate products of terrestrial activity: + +1. 'Granite and syenite' of very different respective ages; the granite is +frequently the more recent,* traversing the syenite in veins, and being, in +that case, the active upheaving agent. "Where the granite occurs in large, +insulated masses of a faintly-arched, ellipsoidal form, it is covered by a +crust of shell cleft into blocks, instances of which are met with alike in +the Hartz district, in Mysore, and in Lower Peru. + + +[footnote] *Bernhard Cotta, 'Geognosie', 1839, s. 273. + + +This surface of the granite, owing to the great expansion that accompanied +its first upheaval."* + + +[footnote] *Leop. von Buch, 'Ueber Granit and Gneiss', in the 'Abhandl. der +Berl. Akad.' for the year 1842, s. 60. + + +Both in Northern Asia,* on the charming and romantic shores of the Lake of +Kolivan, on the northwest declivity of +p. 252 +the Altai Mountains, and at Las Trincheras, on the slop of the littoral +chain of Caraccas,** I have seen granite divided into ledges, owing probably +to a similar contraction, although the divisions appeared to penetrate far +into the interior. + + +[footnote] * In the projecting mural masses of granite of Lake Kolivan, +divided into narrow parallel beds, there are numerous crystals of feldspar +and albite, and a few of titanium (Humboldt, 'Asie Centrale', t. i., p. 295, +Gustav Rose, 'Reise mach dem Ural', bd. i., s. 524). + + +[footnote] *Humboldt, 'Relation Historique', t. ii., p. 99 + + +Further to the south of Lake Kolivan, toward the boundaries of the Chinese +province Ili (between Buchtarminsk and the River Narym), the formation of +the erupted rock, in which there is no gneiss, is more remarkable than I +ever observed in any other part of the earth. The granite, which is always +covered with scales and characterized by tabular divisions, rises in the +steppes, either in small hemispherical eminences, scarcely six or eight feet +in height, or like basalt, in mounds, terminating on either side of their +bases in narrow streams.* + + +[footnote] ** See the sketch of Biri-tau, which I took from the south side, +where the Kirghis tents stood, and which is given in Rose's 'Reise', bd. i., +s. 584. On spheres of granite scaling off concentrically, see my 'Relat. +Hist.', t. ii., p. 497, and 'Essai Geogn. sur les Gisement des Roches', p. +78. + + +At the cataracts of the Orinoco, as well as in the district of the +Fichtelgebirge (Seissen), in Galicia, and between the Pacific and the +highlands of Mexico (on the Papagallo), I have seen granite in large, +flattened spherical masses, which could be divided, like basalt, into +concentric layers. In the valley of Irtysch, between Buchtarminsk and +Ustkamenogorsk, granite covers transition slate for a space of four miles,* +penetrating into it from above in narrow, variously ramified, wedge-like +veins. + + +[footnote] *Humboldt, 'Asie Centrale', t. i., p. 299-311, and the drawings +in Rose's 'Reise', bd. i., s. 611, in which we see the curvature in the +layers of granite which Leop. von Buch has pointed out as chracteristic. + + +I have only instanced these peculiarities in order to designate the +individual character of one of the most generally diffused erupted-rocks. +As granite is superposed on slate in Siberia and in the Departement de +Finisterre (Isle de Mihau), so it covers the Jura limestone in the mountains +of Oisons (Fermonts), and syenite, and indirectly also chalk, in Saxony, +near Weinbohla.* + + +[footnote] *This remarkable superposition was first described by Weiss in +Krsten's 'Archiv fur Bergbau und H¨ttenwesen', bd. xvi., 1827, s. 5. + + +Near Mursinsk, in the Uralian district, granite is of a drusous character, +and here the pores, like the fissures and cavities of recent volcanic +products, inclose many kinds of magnificent crystals, especially beryls and +topazes. + +2. 'Quartzose porphyry' is often found in the relation of veins to other +rocks. The base is generally a finely granular mixture of the same elements +which occur in the larger imbedded +p 253 +crystals. In granitic porphyry that is very poor in quartz, the feldspathic +base is almost granular and laminated.* + + +[footnote] *Dufrenoy et Elie de Beaumont, 'Geologie de la France', t. i., +p. 130. + + +3. 'Greenstones, Diorite', are granular mixtures of white albite and +blackish-green hornblende, forming dioritic porphyry when the crystals are +deposited in a base of denser tissue. The greenstones, either pure, or +inclosing laminae of diallage (as in the Fichtelgebirge), and passing into +serpentine, have sometimes penetrated, in the form of strata, into the old +stratified fissures of green argillaceous slate, but they more frequently +traverse the rocks in veins, or appear as globular masses of greenstone, +similar to domes of basalt and porphyry.* + + +[footnote] *These intercalated beds of diorite play an important part in +the mountain district of Nailau, near Steben, where I was engaged in mining +operations in the last century, and with which the happiest associations of +my early life are connected. Compare Hoffmann, in Poggendorf's 'Annalen', +bd. xvi., s. 558. + + +'Hypersthene rock' is a granular mixture of labradorite and hypersthene. + +'Euphotide' and serpentine, containing sometimes crystald of augite and +uralite instead of diallage, are thus nearly allied to another more +frequent, and I might almost say, more 'energetic' eruptive rock -- augitic +porphyry.* + + +[footnote] *In the southern and Bashkirian portion of the Ural. Rose, +'Reise', bd. ii., s. 171. + + +'Melaphyre', augitic, uralitic, and oligoklastic porphyries. To the +last-named species belongs the genuine 'verd-antique', so celebrated in the +arts. + +'Basalt', containing olivine and constituents which gelatinize in acids; +phonolithe (porphyritic slate), trachyte, and colerite; the first of these +rocks is only paartially, and the second always, divided into thin laminae, +which give them an appearance of stratification when extended over a large +space. Mesotype and nepheline constitute, according to Girard, an important +part in the composition and internal texture of basalt. The nepheline +contained in basalt reminds the geognosist both of the miascite of the Ilmen +Mountains in the Ural,* which has been confounded with granite, and +sometimes contains zirconium, and of the pyroxenic nepheline discovered by +Gumprecht near Lobau and Chemnitz. + + +[footnote] *G. Rose, 'Reise nach dem Ural', bd. ii., s. 47-52. Respecting +the identity of eleolite and uepheline (the latter containing rather the +more lime), see Scheerer, in Poggend., 'Annalen', bd. xlix., s. 359-381. + + +To the second or sedimentary rocks belong the greater part of the formations +which have been comprised under the old +p 254 +systematic, but not very correct designation of 'transition, flot' or +'secondary', and 'tertiary formations'. If the erupted rocks had not +exercised an elevating, and, owing to the simultaneous shock of the earth, a +disturbing influence on these sedimentary formations, the surface of our +planet would have consisted of strata arranged in a uniformly horizontal +direction above one another. Deprived of mountain chains, on whose +declivities the gradations of vegetable forms and the scale of the +diminishing heat of the atmosphere appear to be picturesquely reflected -- +furrowed ony here and there by valleys of erosion, formed by the force of +fresh water moving on in gentle undulations, or by the accumulation of +detritus, resulting from the action of currents of water -- continents would +have presented no other appearance from pole to pole than the dreary +uniformity of the llanos of South America or the steppes of Northern Asia. +The vault of heaven would everywhere have appeared to rest on vast plains, +and the stars to rise as if they emerged from the depths of ocean. Such a +condition of things could not, however, have generally prevailed for any +length of time in the earlier periods of the world, since subterranean +forces must have striven in all epochs to exert a counteracting influence. + +Sedimentary strta have been either precipitated or deposited from liquids, +according as the materials entering into their composition are supposed, +whether as limestone or argillaceous slate, to be either chemically +dissolved or suspended and commingled. But earth, when dissolved in fluids +impregnated with carbonic acid, must be regarded as undergoing a mechanical +process while they are being precipitated, deposited, and accumulated into +strata. This view is of some importance with respect to the envelopment of +organic bodies in petrifying calcareous beds. The most ancient sediments of +the transition and secondary formations have probably been formed from water +at a more or less high temperature, and at a time when the heat of the upper +surface of the earth was still very considerable. Considered in this point +of view, a Plutonic action seems to a certain extent also to have taken +place in the sedimentary strata, especially the more ancient; but these +strata appear to have been hardened into a schistose structure, and under +great pressure, and not to have been solidified by cooling, like the rocks +that have issued from the interior, as, for instance, granite, porphyry, and +basalt. By degrees, as the waters lost their temperature, and were able to +absorb a copious supply of the carbonic acid gas with which +p 255 +the atmosphere was overcharged, they became fitted to hold in solution a +larger quantity of lime. + +'The sedimentary strata', setting aside all other exogenous, purely +mechanical deposits of sand or detritus, are as follows: + +'Schist', of the lower and upper transition rock, compositing the silurian +and devonian formations; from the lower silurian strata, which were once +termed cambrian, to the upper strata of the old red sandstone or devonian +formation, immediately in contact with the mountain limestone. + +'Carboniferous deposits': + +'Limestones' imbedded in the transition and carboniferous formations; +zechstein, muschelkalk, Jura formation and chalk, also that portion of the +tertiary formation which is not included in sandstone and conflomerate. + +'Travertine', fresh-water limestone, and silicious concretions of hot +springs, formations which have not been produced under the pressure of a +large body of sea water, but almost in immediate contact with the +atmosphere, as in shallow marshes and streams. + +'Infusorial deposits': geognostical phenomena, whose great importance in +proving the influence of organic activity in the formation of the solid part +of the earth's crust was first discovered at a recent period by my +highly-gifted friend and fellow-traveler, Ehrenberg. + +If, in this short and superficial view of the mineral constituents of the +earth's crust, I do not place immediately after the simple sedimentary rocks +the conglomerates and sandstone formations which have also been deposited as +sedimentary strata from liquids, and which have been imbedded alternately +with schist and limestone, it is only because they contain, together with +the detritus of eruptive and sedimentary rocks, also the detritus of gneiss, +mica slate, and other metamorphic masses. The obscure process of this +metamorphism, and the action if produces, must therefore compose the third +class of the fundamental forms of rock. + +Endogenous or erupted rocks (granite, porphyry, and melaphyre) produce, as I +have already frequently remarked, not only cynamical, shaking, upheaving +actions, either vertically or laterally displacing the strata, but they also +occasion changes in their chemical composition as well as in the nature of +their internal structure; new rocks being thus formed, as gneiss, mica +slate, and granular limestone (Carrara and Parian marble). The old silurian +or devonian transition schists, the belemnitic limestone of Tarantaise, and +the dull gray calcareous +p 256 +sandstone ('Macigno'), which contains alggae found in the northern +Apennines, often assume a new and more brilliant appearance after their +metamorphosis, which renders it difficult to recognize them. The theory of +metamorphism was not established until the individual phases of the change +were followed step by step, and direct chemical experiments on the +difference in the fusion point, in the pressure and time of cooling, were +brought in aid of mere inductive conclusions. Where the study of chemical +combinations is regulated by leading ideas,* it may be the means of throwing +a clear light on the wide field of geognosy, and over the vast laboratory of +nature in which rocks are continually being formed and modified by the +agency of subterranean forces. + + +[footnote] *See the admirable researches of Mitscherlich, in the 'Abhandl. +der Berl. Akad.' for the years 1822 and 1823, s. 25-41; and in Poggend., +'Annalen', bd. x., s. 137-152; bd. xi., s. 323-332; bd. sli., s. 213-216 +(Gustav Rose, 'Ueber Gildung des Kalkspaths und Aragonits', in Poggend., +'Annalen', bd. xli., s, 353-366; Haidinger, in the 'Transactions of the +Royal Society of Edinburgh', 1827, p. 148.) + + +The philosopohical inquirer will escape the deception of apparent analogies, +and the danger of being led astray by a narrow view of natural phenomena, if +he constantly bear in view the complicated conditions which may, by the +intensity of their force, have modified the counteracting effect of those +individual substances whose nature is better known to us. Simple bodies +have, no doubt, at all periods, obeyed the same laws of attraction, and, +wherever apparent contradictions present themselves, I am confident that +chemistry will in most cases be able to trace the cause to some +corresponding error in the experiment. + +Observations made with extreme accuracy over large tracts of land, show that +erupted rocks have not been produced in an irregular and unsystematic +manner. In parts of the globe most remote from one another, we often find +that granite, basalt, and diorite have exercised a regular and uniform +metamorphic action, even in the minutest details, on the strata of +argillaceous slate, dense limestone, and the grains of quartz in sandstones. + As the same endogenous rock manifests almost every where the same degree of +activity, so on the contrary, different rocks belonging to the same class, +whether to the endogenous or the erupted, exhibit great differences in +their character. Intense heat has undoubtedly influenced all these +phenomena, but the degree of fluidity (the more or less perfect mobility of +the particles -- their more viscous composition) has varied very +considerably from the granite to the basalt, while at different geological +p 257 +periods (or metamorphic phases of the earth's crust) other substances +dissolved in vapors have issued from the interior of the earth +simultaneously with the eruption of granite, basalt, greenstone porphyry, +and serpentine. This seems a fitting place again to draw attention to the +fact that, according to the admirable views of modern geognosy, the +metamorphism of rocks is not a mere phenomenon of contact, limited to the +effect produced by the apposition of two rocks, since it comprehends all the +generic phenomena that have accompanied the appearance of a particular +erupted mass. Even where there is no immediate contact, the proximity of +such a mass gives rise to modifications of solidification, cohesion, +granulation, and crystallization. + +All eruptive rocks penetrate, as ramifying veins either into the sedimentary +strata, or into other equally endogenous masses; but there is a special +importance to be attached to the difference manifested between 'Plutonic' +rocks* (granite, porphyry, and serpentine) and those termed 'volcanic' in +the strict sense of the word (as trachyte, basalt, and lava). + + +[footnote] ([Lyell, 'Principales of Geology', vol. i.i., p. 353 and 359.] +-- Tr. + + +The rocks produced by the activity of our present volcanoes appear as +band-like streams, but by the confluence of several of them they may form an +extended basin. Wherever it has been possible to trace basaltic eruptions, +they have generally been found to terminate in slender threads. Examples of +these narrow openings may be found in three places in Germany: in the +'Pflaster-kaute', at Marksuhl, eight miles from Eisenach; in the blue +'Kuppe', near Eschwege, on the banks of the Werra; and in the Druidical +stone on the Hollert road (Siegen), where the basalt has broken through the +variegated sandstone and graywacke slate, and has spread itself into +cup-like fungoid enlargements, which are either grouped together like rows +of columns, or are sometimes stratified in thin laminae. The case is +otherwise with granite, syenite, quartzose porphyry, serpentine, and the +whole series of unstratified compact rocks, to which, from a predilection +for a mythological nomenclature, the term Plutonic has been applied. These, +with the exception of occasional veins, were probably not erupted in a state +of fusion, but merely in a softened condition; not from narrow fissures, but +from long and widely-extending gorges. They have been protruded, but have +not flowed forth, and are found not in streams like lava, but in extended +masses.* + + +[footnote] *The description here given of the relation of position under +which granite occurs, expresses the general or leading character of the +whole formation. But its aspect at some places leads to the belief that it +was occasionally more fluid at the period of its eruption. The description +given by Rose, in his 'Reise nach dem Ural', bd. i., s. 599, of part of the +Narym chain, near the frontiers of the Chinese territories, as well as the +evidence afforded by trachyte, as described by Dufrenoy and Elie de +Beaumont, in their 'Description Geologique de la France', t. i., p. 70. +Having already spoken in the text of the narrow apertures through which the +basalts have sometimes been effused, I will here notice the large fissures, +which have acted as conducting passages for melaphyres, which must not be +confounded with basalts. See Murchison's interesting account ('The Silurian +System', p. 126) of a fissure 480 feet wide, through which melaphyre has +been ejected, at the coal-mine at Cornbrook, Hoar Edge. + + +Some groups of dolerite and trachyte indicate +p 258 +a certain degree of basaltic fluidity; others, which have been expanded into +vast craterless domes, appear to have been only in a softened condition at +the time of their elevation. Other trachytes, like those of the Andes, in +which I have frequently perceived a striking analogy with the greenstones +and syenitic porphyries (which are argentiferous, and without quartz), are +deposited in the same manner as granite and quartzose porphyry. + +Experiments on the changes which the texture and chemical constitution of +rocks experience from the action of heat, have shown that volcanic masses* +(diorite, augitic porphyry, basalt, and the lava of AEtna) yield different +products, according to the difference of the pressure under which they have +been fused, and the length of time occupied during their cooling; thus, +where the cooling was rapid, they form a black glass, having a homogeneous +fracture, and where the cooling was slow, a stony mass of granular +crystalline structure. + + +[footnote] *Sir James Hall, in the 'Edin. Trans.', vol. v., p. 43, and vol. +vi., p. 71; Gregory Watt, in the 'Phil. Trans. of the Roy. Soc. of London +for' 1804, Part ii., p. 279; Dartigues and Fleurieu de Bellevue, in the +'Journal de Physique', t. lx., p. 456; Bischof, 'Warmelchre', s. 313 und 443. + + +In the latter case, the crystals are formed partly in cavities and partly +inclosed in the matrix. The same materials yield the most dissimilar +products, a fact that is of the greatest importance in reference to the +study of the nature of erupted rocks, and of the metamorphic action which +they occasion. Carbonate of lime, when fused under great pressure, does not +lose its carbonic acid, but becomes, when cooled, granular limestone; when +the crystallization has been effected by the dry method, saccharoidal +marble; while by the humid method, calcareous spar and aragonite and +produced, the former under a lesser degree of temperature than the latter.* + + +[footnote] *Gustav Rose, in Poggend., 'Annalen.' bd. xliii., s 364. + + +Differences of temperature +p 259 +likewise modify the direction in which the different particles arrange +themselves in the act of crystallization, and also affect the form of the +crystal.* + + +[footnote] *On the dimorphism of sulphur, see Mitscherlich, 'Lehrbuch der +Chemie', 55-63. + + +Even when a body is not in a fluid condition, the smallest particles may +undergo certain relations in their various modes of arrangement, which are +manifested by the different action on light.* + + +[footnote] *On gypsum as a uniaxal crystal, and on the sulphate of +magnesia, and the oxyds of zinc and nickel, see Mitscherlich, in Poggend., +'Annalen.' bd. xi., s. 328. + + +The phenomena presented by devitrification, and by the formation of steel by +cementation and casting -- the transition of the fibrous in the granular +tissue of the iron, from the action of heat* and probably, also, by regular +and long-continued concussions -- likewise throw a considerable degree of +light on the geological process of metamorphism. + + +[footnote] *Coste, 'Versuche am Creusot uber das bruchig werden des +Stabeisens.' Elie de Beaumont, 'Mem. Geol.', t. ii., p. 411. + + +Heat may even simultaneously induce opposite actions in crystalline bodies; +for the admirable experiments of Mitscherlich have established the fact* +that calcareous spar, without altering its condition of aggregation, expands +in the direction of one of its axes and contracts in the other. + + +[footnote] * Mitscherlich, 'Ueber die Ausdehnung der Krystallisirten Korper +durch die Warmelehre', in Poggend., 'Annalen', bd. x., s. 151. + + +If we pass from these general considerations to individual examples, we find +that schist is converted, by the vicinity of Plutonic erupted rocks, into a +bluish-black, glistening roofing slate. Here the planes of stratification +are intersected by another system of divisional stratification, almost at +right angles with the former,* and thus indicating an action subsequent to +the alteration. + + +[footnote] * On the double system of divisional planes, see Elie de +Beaumont, 'Geologie de la France', p. 41; Credner, 'Geognosie Thuringens und +des Harzes', s. 40; and Romer, 'Das Rheinische Uebergangsgebirge', 1844. s. +5 und 9. + + +The penetration of silica causes the argillaceous schist to be traversed by +quartz, transforming it, in part, into whetstone and silicious schist; the +latter sometimes containing carbon, and being then capable of producing +galvanic effects on the nerves. The highest degree of silicifaction of +schist is that observed in ribbon jasper, a material highly valuable in the +arts,* and which is produced in the Oural Mountains +p 260 +by the contact and eruption of augitic porphyry (at Orsk), of dioritic +porphyry (at Aufschkul), or of a mass of hypersthenic rock conglomerated +into spherical masses (at Bogoslowsk). At Monte Serrato, in the island of +Elba, according to Frederic Hoffman, and in Tuscany, according to Alexander +Brongniart, it is formed by contact with euphotide and serpentine. + + +[footnote] *The silica is not merely colored by peroxyd of iron, but is +accompanied by clay, lime, and potash. Rose, 'Reise', bd. ii., s. 187. On +the formation of jasper by the action of dioritic porphyry, augite, and by +persthene rock, see Rose, bd. ii., s. 169, 187, und 192. See, also, bd. i., +s. 427, where there is a drawing of the porphyry spheres between which +jasper occurs, in the calcareous graywacke of Bogoslowsk, being produced by +the Plutonic influence of the augitic rock; bd. ii., s. 545; and likewise +Humboldt, 'Asie Centrale', t. i., p. 486. + + +The contact and Plutonic action of granite have sometimes made argillaceous +schist granular, as was observed by Gustav Rose and myself in the Altai +Mountains (within the fortress of Buchtarminsk),* and have transformed it +into a mass resembling granite, consisting of a mixture of feldspar and +mica, in which larger laminae of the latter were again imbedded.** + + +[footnote] *Rose, 'Reise nach dem Ural', bd. i., s. 586-588. + + +[footnote] **In respect to the volcanic origin of mica, it is important to +notice that crystals of mica are found in the basalt of the Bohemian +Mittelgebirge, in the lava that in 1822 was ejected from Vesuvius +(Monticelli, 'Storia del Vesuvio negli Anni 1821 e 1822', 99), and in +fragments of agrillaceous alte imbedded in scoriaceous basalt at Hohenfels, +not far from Gerolstein, in the Eifel (see Mitscherlich, in Leonhard, +'Basalt-Gebilde', s. 244). On the formation of feldspar in argillaceous +schist, through contact with porphyry, occurring between Urval and Poïet +(Forez), see Dufrenoy, in 'Geol. de la France', t. i., p. 137. It is +probably to a similar contact that certain schists near Paimpol, in +Brittany, with whose appearance I was much struck, while making a geological +pedestrian tour through that interesting country with Professor Kunth, owe +their amygdaloid and cellular character, t. i., p. 234. + + +Most geognosists adhere, with Leopold von Buch, to the well-known hypothesis +"that all the gneiss in the silurian strata of the transition formation, +between the Icy Sea and the Gulf of Finland, has been produced by the +metamorphic action of granite.* + + +[footnote] * Leopold von Buch, in the 'Abhandlungen der Akad. der +Wissenschaft zu Berlin, aus dem Jahr' 1842, s. 63, and in the 'Jahrbuchern +fur Wissenschaftliche Kritik Jahrg.' 1840, s. 196. + + +In the Alps, at St. Gothard, calcareous marl is likewise changed from +granite into mica slate, and then transformed into gneiss." Similar +phenomena of the formation of gneiss and mica slate through granite present +themselves in the oolitic group of the Tarantaise,* in which belemnites are +p 261 +found in rocks, which have some claim to be considered as mica slate, and in +the schistose group in the western part of the island of Elba, near the +promontory of Calamita, and the Fichtelgebirge in Baireuth, between Loomitz +and Markleiten.** + +[footnote] * Elie de Beaumont, in the 'Annales des Sciences Naturelles', t. +xv., p. 362-372. "In approaching the primitive masses of Mont Rosa, and the +mountains situated to the west of Coni, we perceive that the secondary +strata gradually lose the characters inherent in their mode of deposition. +Frequently assuming a character apparently arising from a perfectly distinct +cause, but not losing their stratification, they somewhat resemble in their +physical structure a brand of half-consumed wood, in which we can follow the +traces of the ligneous fibers beyond the spots which continue to present the +natural characters of wood." (See, also, the 'Annales des Sciences +Naturelles', t. xiv., p. 118-122, and von Dechen, 'Geognosie', s. 553.) +Among the most striking proofs of the transformation of rocks by Plutonic +action, we must place the belemites in the schists of Nuffenen (in the +Alpine valley of Eginen and in the Gries-glaciers), and the belemnites found +by M. Charpentier in the so-called primitive limestone on the western +descent of the Col de la Seigne, between the Enclove de Monjovet and the +'chalet' of La Lanchette, and which he showed to me at Bex in the autumn of +1822 ('Annales de Chimie', t. xxiii., p. 262). + + +[footnote] ** Hoffmann, in Poggend., 'Annalen', bd. xvi., s. 552, "Strate +of transition argillaceous schist in the Fichtelgebirge, which can be traced +for a length of 16 miles, are transformed into gneiss only at the two +extremities, where they come in contact with granite. We can there follow +the gradual formation of the gneiss, and the development of the mica and of +the feldspathic amygdaloids, in the interior of the argillaceous schist, +which indeed contains in itself almost all the elements of these substances." + + +Jasper, which,* as I have already remarked, is a production formed by the +volcanic action of augitic porphyry, could only be obtained in small +quantities by the ancients, while another material, very generally and +efficiently used by them in the arts, was granular or saccharoidal marble, +which is likewise to be regarded solely as a sedimentary stratum altered by +terrestrial heat and by proximity with erupted rocks. + + +[footnote] * Among the works of art which have come down to us from the +ancient Greeks and Romans, we observe that none of any size -- as columns or +large vases -- are formed from jasper; and even at the present day, this +substance, in large masses, is only obtained from the Ural Mountains. The +material worked as jasper from the Rhubarb Mountain (Raveniaga Sopka), in +Altai, is a beautiful ribboned porphyry. The word 'jasper' is derived from +the Semitic languages; and from the confused description of Theophrastus +('De Lapidibus', 23 and 27) and Pliny (xxxvii., 8 and 9), who rank jasper +among the "opaque gems," the name appears to have been given to fragments of +'jaspachat', and to a substance which the ancients termed 'jasponyx', which +we now know as 'opal-jasper'. Pliny considers a piece of jasper eleven +inches in length so rare as to require his mentioning that he had actually +seen such a specimen: "Magnitudinem jaspidis undecim unciarum vidimus, +formatamque inde effigem Neronis thoracatam." According to Theophrastus, +the stone which he calls emerald, and from which large obelists were cut, +must have been an imperfect jasper. + + +This opinion is corroborated by the accurate observations on the phenomena +of contact, by the remarkable experiments on fusion +p 262 +made by Sir James Hall more than half a century ago, and by the attentive +study of granitic veins, which has contributed so largely to the +establishment of modern geognosy. Sometimes the erupted rock has not +transformed the compact into granular limestone to any great depth from the +point of contact. Thus, for instance, we meet with a slight transformation +-- a penumbra -- as at Belfast, in Ireland, where the basaltic veins +traverse the chalk, and, as in the compact calcareous beds, which have been +partially inflected by the contact of syenitic granite, at the Bridge of +Boscampo and the Cascade of Conzocoli, in the Tyrol (rendered celebrated by +the mention made of it by Count Mazari Peucati).* + + +[footnote[ *Humboldt, 'Lettre a M. Brochant de Villiers', in the 'Annales +de Chimie et de Physique', t. xxiii., p. 261; Leop. von Buch, 'Geog. Briefe +uber das sudliche Tyrol', s. 101, 105, und 273. + + +Another mode of transformation occurs where all the strata of the compact +limestone have been changed into granular limestone by the action of +granite, and syenitic or dioritic porphyry.* + + +[footnote] *On the transformation of compact into granular limestone by the +action of granite, in the Pyrenees at the 'Montagnes de Rancie', see +Dufrenoy, in the 'Memoires Geologiques', t. ii., p. 440; and on similar +changes in the 'Montagnes de l'Oisans', see Elie de Beaumont, in the 'Mem. +Geolog.', t. ii., p. 379-415; on a similar effect produced by the action of +dioritic and pyroxenic porphyry (the 'ophite' described by Elie de Beaumont, +in the 'Geologie de la France', t. i., p. 72), between Tolosa and St. +Sebastian, see Dufrenoy, in the 'Mem. Geolog.', t. ii., p. 130; and by +syenite in the Isle of Skye, where the fossils in the altered limestone may +still be distinguished, see Von Dechen, in his 'Geognosie', p. 573. In the +transformation of chalk by contact with basalt, the transposition of the +most minute particles in the processes of crystallization and granulation is +the more remarkable, because the excellent microscopic investigations of +Ehrenberg have shown that the particles of chalk previously existed in the +form of closed rings. See Poggend., 'Annalen der Physic', bd. xxxix., s. +105; and on the rings of aragonite deposited from solution, see Gustav Rose +in vol. xlii., p. 354, of the same journal. + + +I would here wish to make special mention of Parian and Carrara marbles, +which have acquired such celebrity from the noble works of art into which +they have been converted, and which have too long been considered in our +geognostic collections as the main types of primitive limestone. The action +of granite has been manifested sometimes by immediate contact, as in the +Pyrenees,* and sometimes, as in the main land of Greece, and in the insular +groups in the gean Sea, through the intermediate layers of gneiss or mica +slate. + + +[footnote] *Beds of granular limestone in the granite at Port d'Oo and in +the Mont de Labourd. See Charpentier, 'Constitution Geologique des +Pyrenes', p. 144, 146. + + +Both cases presuppose a simultaneous but heterogeneous process of +transformation. +p 263 +In Attica, in the island of Euboea, and in the Peloponnesus, it has been +remarked, "that the limestone, when superposed on mica slate, is beautiful +and crystalline in proportion to the purity of the latter substance and to +the smallness of its argillaceous contents; and, as is well known, this +rock, together with beds of gneiss, appears at many points, at a +considerable depth below the surface, in the islands of Paros and +Antiparos."* + + +[footnote] *Leop. von Buch, 'Descr. des Canaries', p. 394; Fiedler, 'Reise +durch das Konigreich Griechenland', th. ii., s., 181, 190, und 516. + + +We may here infer the existence of an imperfectly metamorphosed flotz +formation, if faith can be yielded to the testimony of Origen, according to +whom, the ancient Eleatic, Xenophanes of Colophon* (who supposed the whole +earth's crust to have been once covered by the sea), declared that marine +fossils had been found in the quarries of Syracuse, and the impression of a +fish (a sardine) in the deepest rocks of Paros. + + +[footnote] *I have previously alluded to the remarkable passage in Origen's +'Philosophumena', cap. 14 ('Opera', ed. Delarue, t. i., p. 893). From the +whole context, it seems very improbable that Xenophanes meant an impression +of a laurel ([Greek words]) instead of an impression of a fish ([Greek +words]). Delarue is wrong in blaming the correction of Jacob Gronovius in +changing the laurel into a sardel. The petrifaction of a fish is also much +more probable than the natural picture of Silenus, which, according to Pliny +(lib. xxxvi., 5), the quarry-men are stated to have met with in Parian +marble from Mount Marpessos. 'Servius ad Virg., AEn.', vi., 471. + + +The Carrara or Luna marble quarries, which constituted the principal source +from which statuary marble was derived even prior to the time of Augustus, +and which will probably continue to do so until the quarries of Paros shall +be reopened, are beds of calcareous sandstone -- macigno -- altered by +Plutonic action, and occurring in the insulated mountain of Apuana, between +gneiss-like mica and talcose schist.* + + +[footnote] *On the geognostic relations of Carrara ('The City of the Moon', +Strabo, lib. v., p. 222), see Savi 'Osservazioni sui terreni antichi +Toscani', in the 'Nuova Giornale de' Letterati di Pisa', and Hoffmann, in +Karsten's 'Archiv fur Mineralogie', bd. vi., s. 258-263, as well as in his +'Geogn. Reise durch Italien', s. 244-265. + + +Whether at some points granular limestone may not have been formed in the +interior of the earth, and been raised by gneiss and syenite to the surface, +where it forms vein-like fissures,* is a question on which I can not hazard +an opinion, owing to my own want of personal knowledge of the subject. + + +[footnote] *According to the assumption of an excellent and very +experienced observer, Karl von Leonhard. See his 'Jahrbuch fur +Mineralogie', 1834 s. 329, and Bernhard Cotta, 'Geognosie', s. 310. + + +p 264 +According to the admirable observations of Leopold von Buch, the masses of +dolomite found in Southern Tyrol, and on the Italian side of the Alps, +present the most remarkable instance of metamorphism produced by massive +eruptive rocks on compact calcareous beds. The formation of the limestone +seems to have proceeded from the fissures which traverse it in all +directions. The cavities are every where covered with rhomboidal crystals +of magnesian bitter spar, and the whole formation, without any trace of +strtification, or of the fossil remains which it once contained, consists +only of a granular aggregation of crystals of dolomite. Talc laminae lie +scattered here and there in the newly-formed rock, traversed by masses of +serpentine. In the valley of the Fassa, dolomite rises perpendicularly in +smooth walls of dazzling whiteness to a height of many thousand feet. It +forms sharply-pointed conical mountains, clustered together in large +numbers, but yet not in contact with each other. The contour of their forms +recalls to mind the beautiful landscape with which the rich imagination of +Leonardi da Vinci has embellished the back-ground of the portrait of Mona +Lisa. + +The geognostic phenomena which we are now describing, and which excite the +imagination as well as the powers of the intellect, are the result of the +action of augite porphyry manifested in its elevating, destroying, and +transforming force.* + + +[footnote] *Leop. von Buch, 'Geognostische Briefe an Alex. von Humboldt', +1824, s. 86 and 82; also in the 'Annalen de Chemie', t. xxiii., p. 276, and +in the 'Abhandl. der Berliner Akad. aus der Jahren 1822 'und' 1823, s. +83-136; Von Dechen, 'Geognosie.' s. 574-576. + + +The process by which limestone is converted into dolomite is not regarded by +the illustrious investigator who first drew attention to the phenomenon as +the consequence of the tale being derived from the black porphyry, but +rather as a transformatiion simultaneous with the appearance of this erupted +stone through wide fissures filled with vapors. It remains for future +inquirers to determine how transformation can have been effected without +contact with the endogenous stone, where strata of dolomite are found to be +interspersed in imestone. Where, in this case, are we to seek the concealed +channels by which the Plutonic action is conveyed? Even here it may not, +however, be necessary, in conformity with the old Roman adage, to believe +"that much that is alike in nature may have been formed in wholly different +ways." When we find, over widely extended parts of the earth, that two +phenomena are always associated together, as, for instance, the occurrence +of melaphyre +p 265 +and the transformation of compact limestone into a crystaline mass differing +in its chemical character, we are, to a certain degree, justified in +believing, where the second phenomenon is manifested unattended by the +appearance of the first, that this apparent contradiction is owing to the +absence, in certain cases, of some of the conditions attendant upon the +exciting causes. Who would call in question the volcanic nature and igneous +fluidity of basalt merely because there are some rare instances in which +basaltic veins, traversing beds of coal or strata of sandstone and chalk, +have not materially deprived the coal of its carbon, nor broken and slacked +the sandstone, not converted the chalk into granular marble? Wherever we +have obtained even a faint light to guide us in the obscure domain of +mineral formation, we ought not ungratefully to disregard it, because there +may be much that is still unexplained in the history of the relations of the +transitions, or in the isolated interposition of beds of unaltered strata. + +After having spoken of the alteration of compact carbonate of lime into +granular limestone and dolomite, it still remains for us to mention a third +mode of transformation of the same mineral, which is ascribed to the +emission, in the ancient periods of the world, of the vapors of sulphuric +acid. This transformation of limestone into gypsum is analogous to the +penetration of rock salt and sulphur, the latter being deposited from +sulphureted aqueous vapor. In the lofty Cordilleras of Quindin, far from +all volcanoes, I have observed deposits of sulphur in fissures in gneiss, +while in Sicily (at Cattolica, near Girgenti), sulphur, gypsum, and rock +salt belong to the most recent secondary strata, the chalk formations.* + + +[footnote] *Horrman, 'Geogn. Reise', edited by Von Dechen, s. 113-119, and +380-386; Poggend., 'Annalen der Physik', bd. xxvi., s. 41. + + +I have also seen on the edge of the crater of Vesuvius, fissures filled with +rock salt, which occurred in such considerable masses as occasionally to +lead to its being disposed of by contraband trade. On both declivities of +the Pyrenees, the connection of diorite and pyroxene, and colomite, gypsum, +and rock salt, can not be questioned;* and here, as in the other phenomena +which we have been considering, every thing bears evidence of the action of +subterranean forces on the sedimentary strata of the ancient sea. + + +[footnote] *Dufrenoy, in the 'Memoires Geologiques', t. ii., p. 145 and 179. + + +There is much difficulty in explaining the origin of the beds of pure +quartz, which occur in such large quantities in South America, and impart so +peculiar a character to the chain of +p 266 +the Andes.* + + +[footnote] *Humboldt, 'Essai Geogn. sur le Gisement des Roches', p. 93; +'Asie Centrale', t. iii., p. 532. + + +In descending toward the South Sea, from Caxamarca toward Guangamarca, I +have observed vast masses of quartz, from 7000 to 8000 feet in height, +superposed sometimes on porphyry devoid of quartz, and sometimes on diorite. + Can these beds have been transformed from sandstone, as Elie de Beaumont +conjectures in the case of the quartz strata on the Col de la Poissonniere, +east of Briançon?* + + +[footnote] *Elie de Beaumont, in the 'Annales des Sciences Naturelles', t. +xv., p. 362; Murchison, 'Silurian System', p. 286. + + +In the Brazils, in the diamond district of Minas Geraes and St. Paul, which +has recently been so accurately investigated by Clausen, Plutonic action has +developed in dioritic veins sometimes ordinary mica, and sometimes specular +iron in quartzose itacolumite. The diamonds of Grammagoa are imbedded in +strata of solid silica, and are occasionally enveloped in laminae of mica, +like the garnets found in mica slate. The diamonds that occur furthest to +the north, as those discovered in 1829 at 58 degrees lat., on the European +slope of the Uralian Mountains, bear a geognostic relation to the black +carboniferous dolomite of Adolffskoi* and to augitic porphyry, although more +accurate observations are required in order fully to elucidate this subject. + + +[footnote] *Rose, 'Reise nach dem Ural', bd. i., s. 364 und 367. + + +Among the most remarkable phenomena of contact, we must, finally, enumerate +the formation of garnets in argillaceous schist in contact with basalt and +dolerite (as in Northumberland and the island of Anglesea), and the +occurrence of a vast number of beautiful and most various crystals, as +garnets, vesuvian, augite, and ceylanite, on the surfaces of contact between +the erupted and sedimentary rock, as, for instance, on the junction of the +syenite of Monzon with dolomite and compact limestone. + + +[footnote] *Leop. von Buch, 'Briefe', s. 109-129. See also, Elie de +Beaumont 'On the Contact of Granite with the Beds of the Jura', in the 'Mem. +Geol.' t. ii., p. 408. + + +In the island of Elba, masses of serpentine, which perhaps nowhere more +clearly indicate the character of erupted rocks, have occasioned the +sublimation of iron glance and red oxyd of iron in fissures of calcareous +sandstone. + + +[footnote] *Hoffman, 'Reise', s. 30 und 37. + + +We still daily find the same iron glance formed by sublimation from the +vapors and the walls of the fissures of open veins on the margin of the +crater, and in the fresh lava currents of the volcanoes of Stromboli, +Vesuvius, and AEtna.* + + +[footnote] *On the chemical process in the formation of specular iron, see +Gay Lussac, in the 'Annales de Chimie', t. xxii., p. 415, and Mitscherlich, +in Poggend., 'Annalen', bd. xv., s. 630. Moreover, crystals of olivine have +been formed (probaby by sublimation) in the cavities of the obsidian of +Cerro del Jacal, which I brought from Mexico (Gustav Rose, in Poggend., +'Annalen', bd. x., s. 323). Hence olivine occurs in basalt, lava, obsidian, +artificial scoriae in meteoric stones, in the syenite of Elfdale, and (as +hyalosiderite) in the wacke of the Kaiserstuhl. + + +The veins that +p 267 +are thus formed beneath our eyes by volcanic forces, where the contiguous +rock has already attained a certain degree of solidification, show us how, +in a similar manner, mineral and metallic veins may have been every where +formed in the more ancient periods of the world, where the solid but thinner +crust of our planet, shaken by earthquakes, and rent and fissured by the +change of volume to which it was subjected in cooling, may have presented +many communications with the interior, and many passages for the escape of +vapors impregnated with earthy and metallic substances. The arrangement of +the particles in layers parallel with the margins of the beins, the regular +recurrence of analogous layers on the opposite sides of the veins (on their +different walls), and, finally, the elongated cellular cavities in the +middle, frequently afford direct evidence of the Plutonic process of +sublimation in metalliferous veins. As the traversing rocks must be of more +recent origin than the traversed, we learn from the relations of +stratification existing between the porphyry and the argentiferous ores in +the Saxon mines (the richest and most important in Germany), that these +formations are at any rate more recent than the vegetable remains found in +carboniferous strata and in the red sandstone.* + + +[footnote] *Constantin von Veust, 'Ueber die Porphyrgebilde', 1835, s. +89-96; also his 'Belenchtung der Werner'schen Gangtheorie', 1840, s. 6; and +C. von Wissenbach, 'Abbildungen merkwurdiger Gangverhaltnisse', 1836, fig. +12. The ribbon-like structure of the veins is, however, no more to be +regarded of general occurrence than the periodic order of the different +members of these masses. + + +All the facts connected with our geological hypotheses on the formation of +the earth's crust and the metamorphism of rocks have been unexpectedly +elucidated by the ingenious idea which led to a comparison of the slags or +scoriae of our smelting furnaces with natural minerals, and to the attempt +of reproducing the latter from their elements.* + + +[footnote] *Mitscherlich, 'Ueber die kunstliche Darstellung der +Mineralien', in the 'Abhandl. der Akademie der Wiss. zu Berlin', 1822-3, s. +25-41. + + +In all these operations, the same affinities manifest themselves which +determine chemical combinations both in our laboratories and in the interior +of the earth. The most considerable part of +p 268 +the simple minerals which characterize the more generally diffused Plutonic +and erupted rocks, as well as those on which they have exercised a +metamorphic action, have been produced in a crystalline state, and with +perfect identify, in artificial mineral products. We must, however, +distinguish here between the scoriae accidentally formed, and those which +have been designedly produced by chemists. To the former belong feldspar, +mica, augite, olivine, hornblende, crystallized oxyd of iron, magnetic iron +in octahedral crystals, and metallis titanium;* to the latter, garnets, +idocrase, rubies (equal in hardness to those found in the East), olivine, +and augite.** + + +[footnote] *In scoriae crystals of feldspar have been discovered by Heine +in the refuse of a furnace for copper fusing, near Sangerhausen, and +analyzed by Kersten (Poggend., 'Annalen', bd. xxxiii., s. 337); crystals of +augite in scoriae at Sahle (Mitscherlich, in the 'Abhandl. der Akad. zu +Berlin', 1822-23, s. 40); of oliving by Seifstrom (Leonhard, +'Basalt-Gebilde', bd. ii., s. 495); of mica in old scoriae of Schloss +Garpenberg (Mitscherlich, in Leonhard, op. cit., s. 506); of magnetic iron +in the scoriae of Chatillon sur Seine (Leonhard, s. 441); and of micaceous +iron in potter's clay (Mitscherlich, in Leohnard, op. cit., s. 234). +[See Ebelmer's papers in 'Ann. de Chimie et de Physique', 1847; also 'Report +on the Crystalline Slags', by John Percy, M.D., F.R.S., and William Hallows +Miller, M.A., 1847. Dr. Percy, in a communication with which he has kindly +favored me, says that the minerals which he has found artificially produced +and proved by analysis are Humboldtilite, gehlenite, olivine, and magnetic +oxyd of iron, in octahedral crystals. He suggests that the circumstance of +the production of gehlenite at a high temperature in an iron furnace may +possibly be made available by geologists in explaining the formation of the +rocks in which the natural mineral occurs, as in Fassathal in the Tyrol.] -- +Tr. + + +[footnote] **Of minerals purposely produced, we may mention idocrase and +garnet (Mitscherlich, in Poggend., 'Annalen der Physik', bd. xxxii., s. +340); ruby (Gaudin, in the 'Comptes Rendus de l'Academie de Science', t. +iv., Part i., p. 999); olivine and augite (Mitscherlich and Berthier, in the +'Annales de Chimie et de Physique', t. xxiv., p. 376). Notwithstanding the +greatest possible similarity in crystalline form, and perfect identity in +chemical composition, existing, according to Gustav Rose, between augite and +hornblende, hornblende has never been found accompanying augite in scoriae, +nor have chemists ever succeeded in artificially producing either hornblende +or feldspar (Mitscherlich in Poggend., 'Annalen', bd. xxxiii., s. 340, and +Rose, 'Reise nach dem Ural', bd. ii., s. 358 und 363). See also, Beaudant, +in the 'Mem. de l'Acad. des Sciences', t. viii., p. 221, and Becquerel's +ingenious experiments in his 'Trait de l'Electricite,' t. i., p. 334; t. +iii., p. 218; and t. v., p. 148 and 185. + + +These minerals constitute the main constituents of granite, gneiss, and mica +schist, of basalt, dolerite, and many porphyries. The artificial production +of feldspar and mica is of most especial geognostic importance with +reference to the theory of the formation of gneiss by the metamorphic agency +of argillaceous schist, which contains all the constituents of granite, +p 269 +potash not excepted.* + + +[footnote] *D'Aubuisson, in the 'Journal de Physique', t. lxviii., p. 128. + + +It would not be very surprising, therefore, as is well observed by the +distinguished geognosist, Von Dechen, if we were to meet with a fragment of +gneiss formed on the walls of a smelting furnace which was built of +argillaceous slate and graywacke. + +After having taken this general view of the three classes of erupted, +sedimentary, and metamorphic rocks of the earth's crust, it still remains +for us to consider the fourth class, comprising 'conglomerates', or 'rocks +of detrius'. The very term recalls the destruction which the earth's crust +has suffered, and likewise, perhaps reminds us of the process of +cementation, which has connected together, by means of oxyd of iron, or of +some argillaceous and calcareous substances, the sometimes rounded and +sometimes angular portions of fragments. Conglomerates and rocks of +detritus, when considered in the widest sense of the term, manifest +characters of a double origin. The substances which enter into their +mechanical composition have not been alone accumulated by the action of the +waves of the sea or currents of fresh water, for there are some of these +rocks the formation of which can not be attributed to the action of water. +"When basaltic islands and trachytic rocks rise on fissures, friction of the +elevated rock against the walls of the fissures causes the elevated rock to +be inclosed by conglomerates composed of its own matter. The granules +composing the sandstones of many formations have been separated rather by +friction against the erupted volcanic or Plutonic rock than destroyed by the +erosive force of a neighboring sea. The existence of these friction +'conglomerates', which are met with in enormous masses in both hemispheres, +testifies the intensity of the force with which the erupted rocks have been +propelled from the interior through the earth's crust. This detritus has +subsequently been taken up by the waters, which have then deposited it in +the strata which it still covers."* + + +[footnote] *Leop. von Buck, 'Geognost. Briefe', s. 75-82, where it is also +shown why the new red sandstone (the 'Todtliegende' of the Thuringian flotz +formation) and the coal measures must be regarded as produced by erupted +porphyry. + + +Sandstone formations are found imbedded in all strata, from the lower +silurian transition stone to the beds of the tertiary formations, superposed +on the chalk. They are found on the margin of the boundless plains of the +New Continent, both within and without the tropics, extending like +breast-works along the ancient shore, against which the sea once broke its +foaming waves. + +p 270 +If we cast a glance on the geographical distribution of rocks, and their +relations in space, in that portion of the earth's crust which is accessible +to us, we shall find that the most universally distributed chemical +substance is 'silicic acid', generally in a variously-colored and opaque +form. Next to solid silicic acid we must reckon carbonate of lime, and then +the combinations of silicic acid with alumina, potash, and soda, with lime, +magnesia, and oxyd of iron. + +The substances which we designate as 'rocks' are determinate associations of +a small number of minerals, in which some combine parasitically, as it were, +with others, but only under definite relations; thus, for instance, although +quartz (silica), feldspar, and mica are the principal constituents of +granite, these minerals also occur, either individually or collectively, in +many other formations. By way of illustrating how the quantitative +relations of one feldspathic rock differ from another, richer in mica than +the former, I would mention that, according to Mitscherlich, three times +more alumina and one third more silica than that ossessed by feldspar, give +the constituents that enter into the composition of mica. Potash is +contained in both -- a substance whose existence in many kinds of rocks is +probably antecedent to the dawn of vegetation on the earth's surface. + +The order of succession, and the relative age of the different formations, +may be recognized by the superposition of the sedimentary, metamorphic, and +conglomerate strata; by the nature of the formations traversed by the +erupted masses, and -- with the greatest certainty -- by the presence of +organic remains and the differences of their structure. The application of +botanical and zoological evidence to determine the relative age of rocks -- +this chronometry of the earth's surface, which was already present to the +lofty mind of Hooke -- indicates one of the most glorious epochs of modern +geognosy, which has finally, on the Continent at least, been emancipated +from the sway of Semitic doctrines. Palaeontological investigations have +imparted a vivifying breath of grace and diversity to the science of the +solid structure of the earth. + +The fossiliferous strata contain, entombed within them, the floras and +faunas of by-gone ages. We ascend the stream of time, as in our study of +the relations of superposition we descend deeper and deeper through the +different strata, in which lies revealed before us a past world of animal +and vegetable life. Far-extending disturbances, the elevation of great +mountain chains, whose relative ages we are able to define, attest the +p 271 +destruction of ancient and the manifestation of recent organisms. A few of +these older structures have remained in the midst of more recent species. +Owing to the limited nature of our knowledge of existence, and from the +figurative terms by which we seek to hide our ignorance, we apply the +appellation 'recent structure' to the historical henomena of transition +manifested in the organisms as well as in the forms of primitive seas and of +elevated lands. In some cases these organized structures have been +preserved perfect in the minutest details of tissues, integument, and +articulated parts, while in others, the animal, passing over soft +argillaceous mud, has left nothing but the traces of its course,* or the +remains of its undigested food, as in the coprolites.** + + +[footnote] *[In certain localities of the new red sandstone, in the Valley +of the Connecticut, numerous tridactyl markings have been occasionally +observed on the surface of the slabs of stone when split asunder, in like +manner as the ripple-marks appear on the successive layers of sandstone in +Tilgate Forest. Some remarkably distinct impressions of this kind, at +Turner's Falls (Massachusetts), happening to attract the attention of Dr. +James Deane, of Greenfield, that sagacious observer was struck with their +resemblance to the foot-marks left on the mud-banks of the adjacent river by +the aquatic birds which had recenty frequented the spot. The specimens +collected were submitted to Professor G. Hitchcock, who followed up the +inquiry with a zeal and success that have led to the most interesting +results. No reasonable doubt now exists that the imprints in question have +been produced by the tracks of bipeds impressed on the stone when in a soft +state. The announcement of this extraordinary phenomenon was first made by +Professor Hitchcock, in the 'American Journal of Science' (January, 1836), +and that eminent geologist has since published full descriptions of the +different species of imprints which he has detected, in his splendid work on +the geology of Massachusetts. -- Mantell's 'Medals of Creation', vol. ii., +p. 310. In the work of Dr. Mantell above referred to, there is, in vol. +ii., p. 815, an admirable diagram of a slab from Turner's Falls, covered +with numerous foot-marks of birds, indicating the track of ten or twelve +individuals of different sizes.] -- Tr. + + +[footnote] **[From the examination of the fossils spoken of by geologists +under the name of 'Coprolites', it is easy to determine the nature of the +food of the animals, and some other points; and when, as happened +occasionally, the animal was killed while the process of digestion was going +on, the stomach and intestines being partly filled with half-digested food, +and exhibiting the coprolites actually 'in situ', we can make out with +certainty not only the true nature of the food, but the proportionate size +of the stomach, and the length and nature of the intestinal canal. Within +the cavity of the rib of an extinct animal, the palaeontologist thus finds +recorded, in indelible characters, some of those hieroglyphics upon which he +founds his history. -- 'The Ancient World', by +D. T. Ansted, 1847, p. 173.] -- Tr. + + +In the lower Jura formations (the lias of Lyme Regis), the ink bag of the +sepia has been so wonderfully preserved, that the material, which myriads +p 272 +of years ago might have served the animal to conceal itself from its +enemies, still yields the color with which its image may be drawn.* + + +[footnote] *A discovery made by Miss Mary Anning, who was likewise the +discoverer of the coprolites of fish. These coprolites, and the excrements +of the Ichthyosauri, have been found in such abundance in England (as, for +instance, near Lyme Regis), that, according to Buckland's expression, they +lie like potatoes scattered in the ground. See Buckland, 'Geology +considered with reference to Natural Theology', vol. i., p. 188-202 and 305. + With respect to the hope expressed by Hooke "to raise a chronology" from +the mere study of broken and fossilized shells "and to state the interval of +time wherein such or such castrophes and mutations have happened," see his +'Posthumous Works, Lecture', Feb. 29, 1688. +[Still more wonderful is the preservation of the substance of the animal of +certain Cephalopodes in the Oxford clay. In some specimens recently +obtained, and described by Professor Owen, not only the ink bag, but the +muscular mantle, the head, and its crown of arms, are all preserved in +connection with the belemnite shell, while one specimen exhibits the large +eyes and the funnel of the animal, and the remains of two fins, in addition +to the shell and the ink bag. See Ansted's 'Ancient World', p. 147.] -- Tr. + + +In other strata, again, nothing remains but the faint impression of a muscle +shell; but even this, if it belong to a main dividion of mollusca,* may +serve to show the traveler, in some distant land, the nature of the rock in +which it is found, and the organic remains with which it is associated. + + +[footnote] *Leop. von Buch, in the 'Abhandlungen der Akad. der Wiss. zu +Berlin in dem Jahr' 1837, s. 64. + + +Its discovery gives the history of the country in which it occurs. + +The analytic study of primitive animal and vegetable life has taken a double +direction: the one is purely morphological, and embraces, especially, the +natural history and physiology of organisms, filling up the chasms in the +series of still living species by the fossil structures of the primitive +world. The second is more specially geognostic, considering fossil remains +in their relations to the superposition and relative age of the sedimentary +formations. The former has long predominated over the latter, and an +imperfect and superficial comparison of fossil remains with existing species +has led to errors, which may still be traced in the extraordinary names +applied to certain natural bodies. It was sought to identify all fossil +species with those still extant in the same manner as, in the sixteenth +century, men were led by false analogies to compare the animals of the New +Continent with those of the Old. Peter Camper, Sommering, and Blumenbach +had the merit of being the first, by the scientific application of a more +accurate +p 273 +comparative anatomy, to throw light on the osteological branch of +palaeontology -- the archaeology of organic life; but the actual geognostic +views of the doctrine of fossil remains, the felicitous combination of the +zoological character with the order of succession, and the relative ages of +strata, are due to the labors of George Cuvier and Alexander Brongniart. + +The ancient sedimentary formations and those of transition rocks exhibit, in +the organic remains contained within them, a mixture of structures very +variously situated on the scale of progressively-developed organisms. These +strata contain but few plants, as, for instance, some species of Fuci, +Lycopodiaceae which were probably arborescent, Equisetaceae, and tropical +ferns; they present, however, a singular association of animal forms, +consisting of Crustacea (trilobites with reticulated eyes, and Calymene), +Brachiopoda ('Spirifer, Orthis'), elegant Sphaeronites, nearly allied to the +Crinoidea,* Orthoceraitites, of the family of the Cephalopoda, corals, and, +blended with these low organisms, fishes of the most singular forms, +imbedded in the upper silurian formations. + + +[footnote] *Leop. von Buch, 'Gebirgsformationen von Russland', 1840, s. +24-50. + + +The family of the Cephalaspides, whose fragments of the species 'Pterichtys' +were long held to be trilobites, belongs exclusively to the devonian period +(the old red), manifesting, according to Agassiz, as peculiar a type among +fishes as do the Ichthyosauri and Plesiosauri among reptiles.* + + +[footnote] *Agassiz, 'Monographie des Poissons Fossiles du vieux Gres +Rouge', p. vi. and 4. + + +The Goniatites, of the tribe of Ammonites,* a are manifested in the +transition chalk, in the graywacke of the devonian periods, and even in the +latest silurian formations. + + +[footnote] *Leop. von Buch, in the 'Abhandl. der Berl. Akad.', 1838, s. +149-168; Beyrich, 'Beitr. zur Kenntniss des Rheinischen Uebergangagebirges', +1837, s. 45. + + +The dependence of physiological gradation upon the age of the formations, +which has not hitherto been shown with perfect certainty in the case of +invertebrata,* is most regularly manifested in vertebrated animals. + + +[footnote] *Agassiz, 'Recherches sur les Poissons Fossiles', t. i., +'Introd.', p. xviii.; Davy, 'Consolation in Travel', dial. iii. + + +The most ancient of these, as we have already seen, are fishes; next in the +order of succession of formation, passing from the lower to the upper, come +reptiles and mammalia. The first reptile (a Saurian, the Monitor of +Cuvier), which excited the attention of Leibnitz,* is found in cuperiferous +schist of the Zechstein of Thuringa; the Palaeosaurus and Thecodontosaurus +of Bristol are, according to Murchison, of the same age. + + +[footnote] *A Protosaurus, according to Hermann von Meyer. The rib of a +Saurian asserted to have been found in the mountain limestone (carbonate of +lime) of Northumberland (Herm. von Meyer, 'Palaeologica', s. 299), is +regarded by Lyell ('Geology', 1832, vol. i., p. 148) as very doubtful. The +discoverer himself referred it to the alluvial strata which cover the +mountain limestone. + + +The Saurians are found in large numbers in the muschelkalk,* in the keuper, +and in the oolitic formations, where they are the most numerous. + + +[footnote] *F. von Alberti, 'Monographie des Bunten Sandsteins, +Muschelkalks und Keupers', 1834, s. 119 und 314. + + +At the period of these formations there existed Pleiosauri, having long, +swan-like necks consisting of thirty vertebrae; Megalosauri, monsters +resembling the crocodile, forty-five feet in length, and having feet whose +bones were like those of terrestrial mammalia, eight species of large-eyed +Ichthyosauri, the Geosaurus or 'Lacerta gigantea', of Sommering, and +finally, seven remarkable species of Pterodactyles,* of Saurians furnished +with membranous wings. + + +[footnote] *See Hermann von Meyer's ingenious considertions regarding the +organization of the flying Saurians, in his 'Palaeologica', s. 228-252. In +the fossil specimen of the Pterodactylus crassirostris, which, as well as +the loonger known P. longirostris (Ornithocephalus of Sommering), was found +at Solenhofen, in the lithographic slate of the upper Jura formation, +Professor Goldfuss has even discovered traces of the membranous wing, "with +the impressions of curling tufts of hair, in some places a full inch in +length." + + +In the chalk the number of the crocodilial Saurians diminishes, although +this epoch is characterized by the so-called crocodile of Maestricht (the +Mososaurus of Conybeare), and the colossal, probably graminivorous Iguandon. + Cuvier has found animals belonging to the existing families of the +crocodile in the tertiary formation, and Scheuchzer's 'antediluvian man' +('homo diluvii testis'), a large salamander allied to the Axolotl, which I +brought with me from the large Mexican lakes, belongs to the most recent +fresh-water formations of Oeningen.* + + +[footnote] *[Ansted's 'Ancient World', p. 56.] -- Tr. + + +The determination of the relative ages of organisms by the superposition of +the strata has led to important results regarding the relations which have +been discovered between extinct families and species (the latter being but +few in number) and those which still exist. Ancient and modern observations +concur in showing that the fossil floras and faunas differ more from the +present vegetable and animal forms in proportion as they belong to lower, +that is, more ancient sedimentary formations. The numerical relations first +deduced by Cuvier +p 275 +from the great phenomena of the metamorphism of organic life,* have led, +through the admirable labors of Deshayes and Lyell, to the most marked +results, especially with reference to the different groups of the tertiary +formations, which contain a considerable number of accurately investigated +structures. + + +[footnote] *Cuvier, 'Recherches sur les Ossemens Fossiles', t. i., p. +52-57. See, also, the geological scale of epochs in Phillips's 'Geology', +1837, p. 166-185. + + +Agassiz, who has examined 1700 species of fossil fishes, and who estimates +the number of living species which have either been described or are +preserved in museums at 8000, expressly says, in his masterly work, that, +"with the exception of a few small fossil fishes peculiar to the +argillaceous geodes of Greenland, he has not found any animal of this class +in all the transition, secondary or tertiary formations, which is +specifically identical with any still extant fish." He subjoins the +important observation "that in the lower tertiary formations, for instance, +in the coarse granular calcareous beds, and in the London clay,* one third +of the fossil fishes belong to wholly extinct families. + + +[footnote] *[See 'Wonders of Geology', vol. i., p. 230.] -- Tr. + + +Not a single species of a still extant family is to be found under the +chalk, while the remarkable family of the 'Sauroidi' (fishes with enameled +scales), almost allied to reptiles, and which are found from the coal beds +-- in which the larger species lie -- to the chalk, where they occur +individually, bear the same relation to the two families (the Lepidosteus +and Polypterus) which inhabit the American rivers and the Nile, as our +present elephants and tapirs do to the Mastodon and Anaplotheriun of the +primitive world."* + + +[footnote] *Agassiz, 'Poissons Fossiles', t. i., p. 30, and t. iii., p. +1-52; Buckland, 'Geology', vol. i., p. 273-277. + + +The beds of chalk which contain two of these sauroid fishes and gigantic +reptiles, and a whole extinct world of corals and muscles, have been proved +by Ehrenberg's beautiful discoveries to consist of microscopic Polythalamia, +many of which still exist in our seas, and in the middle latitudes of the +North Sea and Baltic. The first group of tertiary formations above the +chalk, which has been designated as belonging to the 'Eocene Period', does +not, therefore, merit that designation, since "the 'dawn of the world' in +which we live extends much further back in the history of the past than we +have hitherto supposed."* + + +[footnote] *Ehrenberg, 'Ueber noch jetzt lebende Thierarten der +Kreidelnldung', in the 'Abhandl. der Berliner Akad.', 1839, s. 164. + + +As we have already seen, fishes, which are the most ancient of all +vertebrata, are found in the silurian transition strata, +p 276 +and then uninterruptedly on through all formations to the strata of the +tertiary period, while Saurians begin with the zechstone. In like manner, +we find the first mammalia ('Thylacotherium Prevostii', and 'T. Bucklandii', +which are nearly allied according to Valenciennes,* with marsupial animals) +in the oolitic formations (Stonesfield schist), and the first birds in the +most ancient cretaceous strata.** + + +[footnote] *Valenciennes, in the 'Comptes Rendus de l'Academie des +Sciences', t. vii., 1838, Part ii., p. 580. + +[footnote] **In the Weald clay; Bendant, 'Geologie', p. 173. The +ornitholites increase in number in the gypsum of the tertiary formations. +Cuvier, 'Ossemens Fossiles', t. ii., p. 302-328. + + +Such are, according to the present state of our knowledge, the lowest* +limits of fishes, Saurians, mammalia, and birds. + + +[footnote] *[Recent collections from the southern hemisphere show that this +distribution was not so universal during the earlier epochs as has generally +been supposed. See papers by Darwin, Sharpe, Morris, and McCoy, in the +'Geological Journal'.] -- Tr'. + + +Although corals and Serpulidae occur in the most ancient formations +simultaneously with highly-developed Cephalopodes and Crustaceans, thus +exhibiting the most various orders grouped together, we yet discover very +determinate laws in the case of many individual groups of one and the same +orders. A single species of fossil, as Goniatites, Trilobites, or +Nummulites, sometimes constitutes whole mountains. Where different +families are blended together, a determinate succession of organisms has not +only been observed with reference to the superposition of the formations, +but the association of certain families and species has also been noticed in +the lower strata of the same formation. By his acute discovery of the +arrangement of the lobes of their chamber-sutures, Leopold von Buch has been +enabled to divide the innumerable quantity of Ammonites into +well-characterized families, and to show that Ceratites appertain to the +muschelkalk, Arietes to the lias, and Goniatites to transition limestone and +graywacke.* + + +[footnote] *Leop. von Buch, in the 'Abhandl. der Berl. Akad.', 1830, s. +135-187. + + +The lower limits of Belemnites are, in the keuper, covered by Jura +limestone, and their upper limits in the chalk formations.* + + +[footnote] *Quenstedt, 'Flotzgebirge Wurtembergs', 1843, s. 135. + + +It appears, from what we now know of this subject, that the waters must have +been inhabited at the same epoch, and in the most widely-remote districts of +the world, by shell-fish, which were at any rate, in part, identical with +the fossil remains found in England. Leopold von Buch has discovered +exogyra and trigonia in the southern hemisphere (volcano of +p 277 +Maypo in Chili), and D'Orbigny has described Ammonites and Gryphites from +the Himalaya and the Indian plains of Cutch, these remains being identical +with those found in the old Jurassic sea of Germany and France. + +The strata which are distinguished by definite kinds of petrifacations, or +by the fragments contained within them, form a geognostic horizon, by which +the inquirer may guide his steps, and arrive at certain conclusions +regarding the identity or relative age of the formations, the periodic +recurrence of certain strata, their parallelism, or their total suppression. + If certain strata, their parallelism, or their total suppression. If we +classify the type of the sedimentary structures in the simplest mode of +generalization, we arrive at the following series in proceeding from below +upward: +1. The so-called 'transition rocks', in the two divisions of upper and +lower graywacke (silurian and devonian systems), the latter being formerly +designated as old red sandstone. +2. The 'lower trias',* comprising mountain limestone, coal-measures, +together with the lower new red sandstone (Todtliegende and Zechstein).** +3. The 'upper trias', including variegated sandstone,** muschelkalk, and +keuper. +4. 'Jura limestone' (lias and oolite). +5. 'Green sandstone', the quader sanstein, upper and lower chalk, +terminating the secondary formations, which begin with limestone. +6. 'Tertiary formations' in three divisions, distinguished as granular +limestone, the lignites, and the sub-Apennine gravel of Italy. + + +[footnote] *Quenstedt, 'Flotzgebirge Wurtembergs', 1843, s. 13. + +[footnote] ** Murchison makes two divisions of the 'bunter sandstone', the +upper being the same as the 'trias' of Alberti, while the lower division, to +which the 'Vosges sandstone' of Elie de Beaumont belongs -- the 'zeckstein' +and the 'todtliegende' -- he forms his 'Permian' system. He makes the +secondary formations commence with the 'upper trias', that is to say, with +the upper division of our (German) bunter sandstone, while the Permian +system, the carboniferous or mountain limestone, and the devonian and +silurian strata, constitute his 'palaeozoic formatiions'. According to +these views, the chalk and Jura constitute the upper, and the keuper, the +muschelkalk, and the bunter sandstone the lower secondary formations, while +the Permian system and the carboniferous limestone are the upper, and the +devonian and silurian strata are the lower palaeooic formation. The +fundamental principles of this general classification are developed in the +great work in which this indefatigable British geologist purposes to +describe the geology of a large part of Eastern Europe. + + +Then follow, in the alluvial beds, the colossal bones of the mammalia of the +primitive world, as the mastodon, dinothrium +p 278 +missurium, and the megatherides, among which is Owen's sloth-like mylodon, +eleven feet in the length.* + + +[footnote] *[See Mantell's 'Wonders of Geology', vol. i., p. 168.] -- Tr. + + +Besides these extinct families, we find the fossil remains of still extant +animals, as the elephant, rhinoceros, ox, horse, and stag. The field near +Bogota, called the 'Campo de Gigantes', which is filled with the bones of +mastodons, and in which I caused excavations to be made, lies 8740 feet +above the level of the sea, while the osseous remains, found in the elevated +plateaux of Mexico, belong to true elephants of extinct species.* + + +[footnote] *Cuvier, 'Ossemens Fossiles', 1821, t. i., p. 157, 261, and 264. + See, also, Humboldt, 'Ueber die Hochebene von Bogota', in the 'Deutschen +Vierteljahrs-schrift', 1839, bd. i., s. 117. + + +The projecting spurs of the Himalaya, the Sewalik Hills, which have been so +zealously investigated by Captain Cantley* and Dr. Falconer, and the +Cordilleras, whose elevations are probably, of very different epochs, +contain, besides numerous mastodons, the sivatherium, and the gigantic land +tortoise of the primitive world ('Colossochelys'), which is twelve feet in +length and six in height, and several extant families, as elephants, +rhinoceroses, and giraffes; and it is a remarkable fact, that these remains +are found in a zone which still enjoys the same tropical climate which must +be supposed to have prevailed at the period of the mastodons.** + + +[footnote] *[The fossil fauna of the Sewalik range of hills, skirting the +southern base of the Himalaya, has proved more abundant in genera and +species of mammalia than that of any other region yet explored. As a +general expression of the leading features, it may be stated, that it +appears to have been composed of representative forms of all ages, from the +'oldest of the tertiary period down to the modern', and of 'all the +geographical' divisions of the Old Continent grouped together into one +comprehensive fauna. 'Fauna Antiqua Sivaliensis', by Hugh Falconer, M.D., +and Major P. T. Cautley.] -- Tr. + + +Having thus passed in review both the inorganic formations of the earth's +crust and the animal remains which are contained within it, another branch +of the history of the organic life still remains for our consideration, +viz., the epoch of vegetation, and the successive floras that have occurred +simultaneously with the increasing extent of the dry land and the +modifications of the atmosphere. The oldest transition strata, as we have +already observed, contain merely cellular marine plants, and it is only in +the devonian system that a few cryptogamic forms of vascular plants +(Calamites and Lycopodiaceae) have been observed.* + + +[footnote] *Beyrich, in Karsteu's 'Archiv fur Mineralogie', 1844, bd. +xviii., s. 218. + + +Nothing appears to corroborate +p 279 +the theoretical views that have been started regarding the simplicity of +primitive forms of organic life, ow that vegetable preceded animal life, and +that the former was necessarily dependent upon the latter. The existence of +races of men inhabiting the icy regions of the North Polar lands, and whose +nutriment is solely derived from fish and cetaceans, shows the possibility +of maintaining life independently of vegetable substances. After the +devonian system and the mountain limestone, we come to a formation, the +botanical analysis of which has made such brilliant advances in modern +times.* + + +[footnote] *By the important labors of Count Sternberg, Adolphe Brongniart, +Goppert, and Lindley. + + +The coal measures contain not only fern-like cryptogamic plants and +phanerogamic monocotyledons (grasses, yucc-like Liliaceae and palms), but +also gymnospermic dicotyledons (Coniferae and Cycadeae), amounting in all to +nearly 400 species, as characteristic of the coal formations. Of these we +will only enumerate arborescent Calamites and Lycopodiaceae, scaly +Lepidodendra, Sigillariae, which attain a height of sixty feet, and are +sometimes found standing upright, being distinguished by a double system of +vascular bundles, cactus-like Stigmariae, a great number of ferns, in some +cases the stems, and in others the fronds alone being found, indicating by +their abundance the insular form of the dry land,* Cycadeae** especially +palms, although fewer in number.*** + + +[footnote] *See Robert Brown's 'Botany of Congo', p. 42, and the Memoir of +the unfortunate E'Urville, 'De la Distribution des Fougeres sur la Surface +du Globe Terrestre'. + + +[footnote] **Such are the Cycadeae discovered by Count Sternberg in the old +carboniferous formation at Radnitz, in Bohemia, and described by Corda (two +species of Cycatides and Zamites Cordai. See Goppert, 'Fossile Cycadeen in +den Arbeiten der Schles. Gesellschaft, fur waterl. Cultur im Jahr' 1843, s. +33, 37, 40 and 50). A Cycadea (Pterophyllum gonorchachis, Gopp.) has also +been found in the carboniferous formations in Upper Silesia, at Konigshutte. + + +[footnote] ***Lindley, 'Fossil Flora', No. xv., p. 163. + + +Asterophyllites, having whorl-like leaves, and allied to the Naiades, with +araucaria-like Coniferae',* which exhibit faint traces of annual rings. + + +[footnote] *'Fossil Coniferae', in Buckland's 'Geology', p. 483-490. +Witham has the great merit of having first recognized the existence of +Coniferae in the early vegetation of the old carboniferous formation. +Almost all the trunks of trees found in this formation were previously +regarded as palms. The species of the genus 'Araucaria' are, however, not +peculiar to the coal formations of the British Islands; they likewise occur +in Upper Silesia. + + +This difference of character from our present vegtation, minifested in the +vegetative forms which were so luxuriously developed on the drier +p 280 +and more elevated portions of the old red sandstone, was maintained through +all the subsequent epochs to the most recent chalk formations; amid the +peculiar characteristics exhibited in the vegetable forms contained in the +coal measures, there is, however, a strikingly-marked prevalence of the same +families, if not of the same species,* in all parts of the earth as it then +existed, as in New Holland, Canada, Greenland, and Melville Island. + + +[footnote[ *Adolphe Brongniart, 'Prodrome d'une Hist. des Vegetaux +Fossiles', p. 179; buckland, 'Geology', p. 479; Endlicher and Unger, +'Grundzuge der Botanik', 1843, s. 455. + + +The vegetation of the primitive period exhibits forms which, from their +simultaneous affinity with several families of the present world, testify +that many intermediate links must have become extinct in the scale of +organic development. Thus, for example, to mention only two instances, we +would notice the Lepidodendra, which, according to Lindley, occupy a place +between the Coniferae and the Lycopodiaceae*, and the Araucariae and pines, +which exhibit some peculiarities in the union of their vascular bundles. + + +[footnote] *"By means of Lepidodendron, a better passage is established +from flowering to flowerless plants than by either Equisetum or Cycas, or +any other known genus." -- Lindley and Hutton, 'Fossil Flora', vol. ii., p. +53. + + +Even if we limit our consideration to the present world alone, we must +regard as highly important the discovery of Cycadeae and Coniferae side by +side with Sagenariae and Lepidodendra in the ancient coal measures. The +Coniferae are not ony allied to Cupuliferae and Betulinae, with which we +find them associated in lignite formations, but also with Lycopodiaceae. +The family of the sago-like Cycadeae approaches most nearly to palms in its +external appearance, while these plants are specially allied to Coniferae in +respect to the structure of their blossoms and seed.* + + +[footnote] *Kunth, 'Anordnung der Pflanzenfamilien', in his 'Handb. der +Botanik', s. 307 und 314. + + +Where many beds of coal are superposed over one another, the families and +species are not always blended, being most frequently grouped together in +separate genera; Lycopodiaceae and certain ferns being alone found in one +bed, and Stigmariae and Sigillariae in another. In order to give some idea +of the luxuriance of the vegetation of the primitive world, and of the +immense masses of vegetable matter which was doubtlessly accumulated in +currents and converted in a moist condition into coal,* I would instance the +Saarbrucker coal measures, +p 281 +where 120 beds are superposed on one another, exclusive of a great many +which are less than a foot in thickness; the coal beds at Johnstone, in +Scotland, and those in the Creuzot, in Burgundy, are some of them, +respectively, thirty and fifty feet in thickness,** while in the forests of +our temperate zones, the carbon contained in the trees growing over a +certain area would hardly suffice, in the space of a hundred years, to cover +it with more than a stratum of seven French lines in thickness.*** + + +[footnote] That coal has not been formed from vegetable fibers charred by +fire, but that it has more probably been produced in the moist way by the +action of sulphuric acid, is strikingly demonstrated by the excellent +observation made by Goppert (Karsten, 'Archiv fu Mineralogie', bd. xviii., +s. 530), on the conversion of a fragment of amber-tree into black coal. The +coal and the unaltered amber lay side by side. Regarding the part which the +lower forms of vegetation may have had in the formation of coal beds, see +Link, in the 'Abhandl. der Berliner Akademie der Wissenschaften', 1838, s. +38. + + +[footnote] **[The actual total thickness of the different beds in England +varies considerably in different districts, but appears to amount in the +Lancashire coal field to as much as 150 feet. -- Ansted's 'Ancient World', +p. 78. For an enumeration of the thickness of coal measures in America and +the Old Continent, see Mantell's 'Wonders of Geology', vol. ii., p. 60.] -- +Tr. + + +[footnote] ***See the accurate labors of Chevandier, in the 'Comptes Rendus +de l'Academie des Sciences', 1844, t. xviii., Part i., p. 285. In comparing +this bed of carbon, seven lines in thickness, with beds of coal, we must not +omit to consider the enormous pressure to which the latter have been +subjected from superimposed rock, and which manifests itself in the +flattened form of the stems of the trees found in these subterranean +regions. "The so-called 'wood-hills' discovered in 1806 by Sirowatskoi, on +the south coast of the island of New Siberia, consist, according to +Hedenstrom, of horizontal strata of sandstone, aolternating with bituminous +trunks of trees, forming a mound thirty fathoms in neight; at the summit the +stems were in a vertical position. The bed of driftwood is visible at five +wersts' distance." -- See Wrangel, 'Reise Iangs der Nordkuste von Siberien, +in den Jahren' 1820-24, th. i., s. 102. + + +Near the mouth of the Mississippi, and in the "wood hills" of the Siberian +Polar Sea, described by Admiral Wrangel, the vast number of trunks of trees +accumulated by river and sea water currents affords a striking instance of +theenormous quantities of drift-wood which must have favored the formation +of carboniferous deposition in the island waters and insular bays. There +can be no doubt that these beds owe a considerable portion of the substances +of which they consist to grasses, small branching shrubs, and cryptogamic +plants. + +The association of palms and Coniferae, which we have indicated as being +characteristic of the coal formations, is discoverable throughout almost all +formations to the tertiary period. In the present condition of the world, +these genera +p 282 +appear to exhibit no tendency whatever to occur associated together. We +have so accustomed ourselves, although erroneously, to regard Coniferae as a +northern form, that I experienced a feeling of surprise when, in ascending +from the shores of the South Pacific toward Chilpansingo and the elevated +valleys of Mexico, between the 'Venta de la Moxonera' and the 'Alto de los +Caxones', 4000 feet above the level of the sea, I rode a whole day through a +dense wood of Pinus occidentalis, where I observed that these trees, which +are so similar to the Weymouth pine, were associated with fan palms* +('Corypha dulcis'), swarming with brightly-colored parrots. + + +[[footnote] *This corypha is the 'soyate' (in Aztec, zoyatl), or the 'Palma +dulce' of the natives. See Humboldt and Bonplaud, 'Synopsis Plant. +AEquinoct. Orbis Novi', t. i., p. 302. Professor Buschmann, who is +profoundly acquainted with the American languages, remarks, that the 'Palma +soyate' is so named in Yepe's 'Vocabulario de la Lengua Othomi', and that +the Aztec word zoyatl (Molina, 'Vocabulario en Lengua Mexicana y +Castellana', p. 25) recurs in names of places, such as Zoyatitlan and +Zoyapanco, near Chiapa. + + +South America has oaks, but not a single species of pine; and the first time +that I again saw the familiar form of a fir-tree, it was thus associated +with the strange appearance of the fan palm.* + + +[footnote] *Near Baracoa and Cayos de Moya. See the Admiral's journal of +the 25th and 27th of November, 1492, and Humboldt, 'Examen Critique de +l'Hist. de la Geographie du Nouveau Continent', t. ii., p. 252, and 5. iii., +p. 23. Columbus, who invariably paid the most remarkable attention to all +natural objects, was the first to observe the difference between +'Podocarpus' and 'Pinus'. "I find," said he, "en la tierra aspera del Cibao +pinos que no Ilevan pinas (fir cones), pero portal orden compuestos por +naturaleza, que (los frutos) parecen azeytunas del Axarafe de Sevilla." The +great botanist, Richard, when he published his excellent Memoir on Cycadeae +and Coniferae, little imagined that before the time of L'Heritier, and even +before the end of the fifteenth century, a navigator had separated +'Podocarpus' from the Abietineae. + + +Christopher Columbus, in his first voyage of discovery, saw Coniferae and +palms growing together on the northeastern extremity of the island of Cuba, +likewise within the tropics, and scarcely above the level of the sea. This +acute observer, whom nothing escaped, mentions the fact in his journal as a +remarkable circumstance, and his friend Anghiera, the secretary of Frdinand +the Catholic, remarks with astonishment "that 'palmeta' and 'pineta' are +found associated together in the newly-discovered land." It is a matter of +much importance to geology to compare the present distribution of plants +over the earth's surface with that exhibited in the fossil floras of the +primitive world. The temperate zone of the southern hemisphere, which is so +rich in seas and islands, and where +p 283 +tropical forms blend so remarkably with those of colder parts of the earth, +presents according to Darwin's beautiful and animated descriptions,* the +most instructive materials for the study of the present and the past +geography of plants. + + +[footnote] *Charles Darwin, 'Journal of the Voyages of the Adventure and +Beagle', 1839, p. 271. + + +The history of the primordial ages is, in the strict sense of the word, a +part of the history of plants. + +Cycadeae, which, from the number of their fossil species, must have occupied +a far more important part in the extinct than in the present vegetable +world, are associated with the nearly allied Coniferae from the coal +formations upward. They are almost wholly absent in the epoch of the +variegated sandstone which contains Coniferae of rare and luxuriant +structure ('Voltizia, Haidingera, Albertia'); the Cycadeae, however, occur +most frequently in the keuper and lias strata, in which more than twenty +different forms appear. In the chalk, marine plants and naiades +predominate. The forests of Cycadeae of the Jura formations had, therefore, +long disappeared, and even in the more ancient tertiary formations they are +quite subordinate to the Coniferae and palms.* + + +[footnote] *Goppert describes three other Cycadeae (species of Cycadites +and Pterophyllum), found in the brown carboniferous schistose clay of +Alt-sattel and Commotau, in Bohemia. They very probably belong to the +Eocene Period. Goppert, 'Fossile Cycadeen', s. 61. + + +The lignites, or beds of brown coal* which are present in all divisions of +the tertiary period, present, among the most ancient cryptogamic land +plants, some few palms, many Coniferae having distinct annual rings, and +foliaceous shrubs of a more or less tropical character. + + +[footnote] *['Medals of Creation', vol. i., ch. v., etc. 'Wonders of +Geology', vol. i., p. 278, 392.] -- Tr. + + +In the middle tertiary period we again find palms and Cycadeae fully +established, and finally a great similarity with our existing flora, +manifested in the sudden and abundant occurrence of our pines and firs, +Cupuliferae, maples, and poplars. The dicotyledonous stems found in lignite +are occasionally distinguished by colossal size and great age. In the trunk +of a tree found at Bonn, Noggerath counted 792 annual rings.* + + +[footnote] *Buckland, 'Geology', p. 509. + + +In the north of France, at Yseux, near Abbeville, oaks have been discovered +in the turf moors of the Somme which measured fourteen feet in diameter, a +thickness which is very remarkable in the Old Continent and without the +tropics. According to Goppert's excellent investigations, which, it is +hoped, may soon be illustrated by plates, it would appear that "all the +amber of the Baltic comes from +p 284 +a coniferous tree, which, to judge by the still extant remains of wood and +the bark at different ages, approaches very nearly to our white and red +pines, although forming a distinct species. The amber-tree of the ancient +world ('Pinites succifer') abounded in resin to a degree far surpassing that +manifested by any extant coniferous tree; for not only were large masses of +amber deposited in and upon the bark, but also in the wood itself, following +the course of the medullary rays, which, together with ligneous cells, are +still discernible under the microscope, and peripherally between the rings, +being some times both yellow and white." + +"Among the vegetable forms inclosed in amber are male and femald blossoms of +our native needle-wood trees and Cupuliferae, while fragments which are +recognized as belonging to thuia, cupressus, ephedera, and castania vesca, +blended with those of junipers and firs, indicate a vegetation different +from that of the coasts and plains of the Baltic."* + + +[footnote] *{The forests of amber-pines, 'Pinites succifer', were in the +southeastern part of what is now the bed of the Baltic, in about 55 degrees +N. lat., and 37 degrees E. long. The different colors of amber are derived +from local chemical admixture. The amber contains fragments of vegetable +matter, and from these it has been ascertained tht the amber-pine forests +contained four other species of pine (besides the 'Pinites succier'), +several cypresses, yews, and junipers, with oaks, poplars, beeches, etc. -- +altogether forty-eight species of trees and shrubs, constituting a flora of +North American chracter. There are also some ferns, mosses, fungi, and +liverworts. See Professor Goppert, 'Geol. Trans.', 1845. Insects, spiders, +small crustaceans, leaves, and fragments of vegetable tissue, are imbedded +in some of the masses. Upward of 800 species of insects have been observed; +most of them belong to species, and even genera, that appear to be distinct +from any now known, but others are nearly related to indigenous species, and +some are identical with existing forms, that inhabit more southern climes. +-- 'Wonders of Geology', vol. i., p. 242, etc.] -- Tr. + + +We have now passed through the whole series of formations comprised in the +geological portion of the present work, proceeding from the oldest erupted +rock and the most ancient sedimentary formations to the alluvial land on +which are scattered those large masses of rock, the causes of whose general +distribution have been so long and variously discussed, and which are, in my +opinion, to be ascribed rather to the penetration and violent outpouring of +pent-up waters by the elevation of mountain chains than to the motion of +floating blocks of ice.* + + +[footnote] *Leopold von Buch, in the 'Abhandl. der Akad. der Wissensch. zu +Berlin', 1814-15, s. 161; and in Poggend., 'Annalen', bd. ix., s. 575; Elie +de Beaumont, in the 'Annales des Sciences Naturelles', t. xix., p. 60. + + +The most ancient structures of the transition formation +p 285 +with which we are acquainted are slate and graywacke, which contain some +remains of sea weeds from the silurian or cambrian sea. On what did these +so-called 'most ancient' formations rest, if gneiss and mica schist must be +regarded as changed sedimentary strata? Dare we hazard a conjecture on that +which can not be an object of actual geognostic observation? According to +an ancient Indian myth, the earth is borne up by an elephant, who in his +turn is supported by a gigantic tortoise, in order that he may not fall; but +it is not permitted to the credulous Brahmins to inquire on what the +tortoise rests. We venture here upon a somewhat similar problem, and are +prepared to meet with opposition in our endeavors to arrive at its soluion. +In the first formation of the planets, as we stated in the astronomical +portion of this work, it is probable that nebulous rings revolving round the +sun were agglomerated into spheroids, and consolidated by a gradual +condensation proceeding from the exterior toward the center. What we term +the ancient silurian strata are thus only the upper portions of the solid +crust of the earth. The erupted rocks which have broken through and +upheaved these strata have been elevated from depths that are wholly +inaccessible to our research; they must, therefore, have existed under the +silurian strata, and been composed of the same association of minerals which +we term granite, augite, and quartzose porphyry, when they are made known to +us by eruption through the surface. Basing our inquiries on analogy, we may +assume that the substances which fill up deep fissures and traverse the +sedimentary strata are merely the ramifications of a lower deposit. The +foci of active volcanoes are situated at enormous depths, and judging from +the remarkable fragments which I have found in various parts of the earth +incrusted in lava currents, I should deem it more than probable tht a +primordial granite rock forms the substratum of the whole stratified edifice +of fossil remains.* + + +[footnote] *See Elie de Beaumont, 'Descr. Geol. de la France', t. i., p. +65; Beaudant, 'Geologie', 1844, p. 269. + + +Basalt containing olivine first shows itself in the period of the chalk +trachyte still later, while eruptions of granite belong, as we learn from +the products of their metamorphic action to the epoch of the oldest +sedimentary strata of the transition formation. Where knowledge can not be +attained from immediate perceptive evidence, we may be allowed from +induction, no less than from a careful comparison of facts, to hazard a +conjecture by which granite would be restored +p 286 +to a portion of its contested right and title to be considered as a +'primordial' rock. + +The recent progress of geognosy, that is to say, the more extended knowledge +of the geognostic epochs characterized by differences of mineral formations, +by the peculiarities and succession of the organisms contained within them, +and by the position of the strata, whether uplifted or inclined +horizontally, leads us, by means of the causal connection existing among all +natural phenomena, to the distribution of solids and fluids into the +continents and seas which constitute the upper crust of our planet. We here +touch upon a point of contact between geological and geographical geognosy +which would constitute the complete history of the form and extent of +continents. The limitation of the solid by the fluid parts of the earth's +surface and their mutual relations of area, have varied very considerably in +the long series of geognostic epochs. They were very different, for +instance, when carboniferous strata were horizontally deposited on the +inclined beds of the mountain limestone and old red sandstone; when lias and +oolite lay on a substratum of keuper and muschelkalk, and the chalk rested +on the slopes of green sandstone and Jura limestone. If, with Elie de +Beaumont, we term the waters in which the Jura limestone and chalk formed a +soft deposit the 'Jurassic or oolitic', and the 'cretaceous seas', the +outlines of these formations will indicate, for the two corresponding +epochs, the boundaries between the already dried land and the ocean in which +these rocks were forming. An ingenious attempt has been made to craw maps +of this physical portion of primitive geography and we may consider such +diagrams as more correct than those of the wanderings of Io or the Homeric +geography, since the latter are merely graphic representations of mythical +images, while the former are based upon positive facts deduced from the +science of geology. + +The results of the investigations made regarding the areal relations of the +solid portions of our planet are as follows: in the most ancient times, +during the silurian and devonian transition epochs, and in the secondary +formations, including the trias, the continental portions of the earth were +limited to insular groups covered with vegetation; these islands at a +subsequent period became united, giving rise to numerous lakes and +deeply-indented bays; and finally, when the chains of the Pyrenees, +Apennines, and Carpathian Mountains were elevated about the period of the +more ancient tertiary formations, large continents appeared, having almost +their present +p 287 +size.* + + +[footnote] *[These movements, described in so few words, were doubtless +going on for many thousands and tens of thousands of revolutions of our +planet. They were accompanied, also, by vast but slow changes of other +kinds. The expansive force employed in lifting up, by mighty movements, the +northern portion of the continent of Asia, found partial vent; and from +partial subsqueous fissures there were poured out the tabular masses of +basalt occurring in Central India, while an extensive area of depression in +the Indian Ocean, marked by the coral islands of the Laccadives, the +Maldives, the great Chagos Bank, and some others, were in the course of +depression by a counteracting movement. -- Ansted's 'Ancient World', p. 346, +etc.] -- Tr. + + +In the silurian epoch, as well as in that in which the Cycadeae flourished +in such abundance, and gigantic saurians were living, the dry land, from +pole to pole, was probably less than it now is in the South Pacific and the +Indian Ocean. We shall see, in a subsequent part of this work, how this +preponderating quantity of water, combined with other causes, must have +contributed to raise the temperature and induce a greater uniformity of +climate. Here we would only remark in considering the gradual extension of +the dry land, that, shortly before the 'disturbances' which at longer or +shorter intervals caused the sudden destruction of so great a number of +colossal vertebrata in the 'diluvial period', some parts of the present +continental masses must have been completely separated from one another. +There is a great similarity in South America and Australia between still +living and extinct species of animals. In New Holland, fossil remains of +the kangaroo have been found, and in New Zealand the semi-foxxilized bones +of an enormous bird, resembling the ostrich, the dinornis of Owen,* which is +nearly allied to the present spteryx, and but little so to the recently +extinct dronte (dodo) of the island of Rodriguez. + + +[[footnote] *[See 'American Journal of Science', vol. xiv., p. 187; and +'Medals of Creation', vol. ii., p. 817; 'Trans. Zoolog. Society of London', +vol. ii; 'Wonders of Geology', vol. i., p. 129.] -- Tr. + + +The form of the continental portions of the earth may, perhaps, in a great +measure, owe their elevation above the surrounding level of the water to the +eruption of quartzose porphyry, which overthrew with violence the first +great vegetation from which the matrial of our present coal measures was +formed. The portions of the earth's surface which we term plains are +nothing more than the broad summits of hills and mountains whose bases rest +on the bottom of the ocean. Every plain is, therefore, when considered +according to its submarine relations, an 'elevated plateau', whose +inequalities have been covered over by horizontal deposition of new +sedimentary formations and by the accumulation of alluvium. + +p 288 +Among the general subjects of contemplation appertaining to a work of this +nature, a prominent place must be given, first, in the consideration of the +'quantity' of the land raised above the level of the sea, and next, to the +individual configuration of each part, either in relation to horizontal +extension (relations of form) or to vertical elevation (hypsometrical +relations of mountain-chains). Our planet has two envelopes, of which one, +which is general -- the atmosphere -- is composed of an elastic fluid, and +the other -- the sea -- is only locally distributed, surrounding, and +therefore modifying, the form of the land. These two envelopes of air and +sea constitute a natural whole, on which depend the difference of climate on +the earth's surface, according to the relative extension of the aqueous and +solid parts, the form and aspect of the land, and the direction and +elevation of mountain chains. A knowledge of the reciprocal action of air, +sea, and land teaches us that great meteorological phenomena can not be +comprehended when considered independently of geognostic relations. +Meteorology, as well as the geography of plants and animals, has only begun +to make actual progress since the mutual dependence of the phenomena to be +investigated has been fully recognized. The word climate has certainly +special reference to the character of the atmosphere, but this character is +itself dependent on the perpetually concurrent influences of the ocean, +which is universally and deeply agitated by currents having a totally +opposite temperature, and of radiation from the dry land, which varies +greatly in form, elevation, color, and fertility, whether we consider its +bare, rocky portions, or those that are covered with arborescent or +herbaceous vegetation. + +In the present condition of the surface of our planet, the area of the solid +is to that of the fluid parts as 1:2 4/5ths (according to Rigaud, as +100:270).* + + +[footnote] *See 'Transactions of the Cambridge Philosophical Society', vcl. +vi., Part ii., 1837, p. 297. Other writers have given the ratio as 100:284. + + +The islands form scarcely 1/22d of the continental masses, which are so +unequally divided that they consist of three times more land in the northern +than in the southern hemisphere; the latter being, therefore, pre-eminently +oceanic. From 40 degrees south latitude to the Antarctic pole the earth is +almost entirely covered with water. The fluid element predominates in like +manner between the eastern shores of the Old and the western shores of the +New Continent, being only interspersed with some few insular groups. The +learned hydrographer Fleurieu has very justly named this +p 289 +vast oceanic basis, which, under the tropics, extends over 145ºdegrees of +longitude, the 'Great Ocean', in contradistinction to all other seas. The +southern and western hemispheres (reckoning the latter from the meridian of +Teneriffe) are therefore more rich in water than in any other region of the +whole earth. + +These are the main points involved in the consideration of the relative +quantity of land and sea, a relation which exercises so important an +influence on the distribution of temperature, the variations in atmospheric +pressure, the direction of the winds, and the quantity of moisture contained +in the air, with which the development of vegetation is so essentially +connected. When we consider that nearly three fourths of the upper surface +of our planet are covered with water,* we shall be less surprised at the +imperfect condition of meteorology before the beginning of the present +century, since it is only during the subsequent period that numerous +accurate observations on the temperature of the sea at different latitudes +and at different seasons have been made and numerically compared together. + + +[footnote] *In the Middle Ages, the opinion prevailed that the sea covered +one seventh of the surface of the globe, an opinion which Cardinal d'Ailly +('Imago Mundi', cap. 8) founded on the fourth apocryphal book of Esdras. +Columbus, who derived a great portion of his cosmographical knowledge from +the cardinal's work, was much interested in upholding this idea of the +smallness of the sea, to which the misunderstood expression of "the ocean +stream" contributed not a little. See Humboldt, 'Examen Critique de l'Hist. +de la Geographie', t. i., +p. 186. + + +The horizontal configuration of continents in their general relations of +extension was already made a subject of intellectual contemplation by the +ancient Greeks. Conjectures were advanced regarding the maximum of the +extension from west to east, and Dicaearchus placed it, according to the +testimony of Agathemerus, in the latitude of Rhodes, in the direction of a +line passing from the Pillars of Hercules to Thine. This line, which has +been termed 'the parallel of the diaphragm of Dicaearchus', is laid down +with an astronomical accuracy of position, which, as I have stated in +another work, is well worthy of exciting surprise and admiration.* + + +[footnote] *Agathemerus, in Hudson, 'Geographi Minores', t. ii., p. 4. See +Humboldt, 'Asie Centr.', t. i., p. 120-125. + + +Strabo, who was probably influenced by Eratosthenes, appears to have been so +firmly convinced that this parallel of 36 degrees was the maximum of the +extension of the then existing world, that he supposed it had some intimate +connection with the form of the earth, and therefore places under this line +the continent whose existence +p 290 +he divined in the northern hemisphere, between Theria and the coasts of +Thine.* + + +[footnote] *Strabo, lib. i., p. 65, Casaub. See Humboldt, 'Examen Crit.', +t. i., p. 152. + + +As we have already remarked, one hemisphere of the earth (whether we divide +the sphere through the equator or through the meridian of Teneriffe) has a +much greater expansion of elevated land than the opposite one: these two +vast ocean-girt tracts of land, which we term the eastern and western, or +the Old and New Continents, present, however, conjointly with the most +striking contrasts of configuration and position of their axes, some +similarities of form, especially with reference to the mutual relations of +their opposite coasts. In the eastern continent, the predominating +direction -- the position of the major axis -- inclines from east to west +(or, more correctly speaking, from southwest to northeast), while in the +western continent it inclines from south to north (or, rather, from +south-southeast to north-northwest). Both terminate to the north at a +parallel coinciding nearly with that of 70ºdegrees, while they extend to +the south in pyramidal points, having submarine prolongations of islands and +shoals. Such, for instance, are the Archipelago of Tierra del Fuego, the +Lagullas Bank south of the Cape of Good Hope, and Van Diemen's Land, +separated from New Holland by Bass's Straits. Northern Asia extends to the +above parallel at Cape Taimura, which, according to Krusenstern, is 78 +degrees 16', while it falls below it from the mouth of the Great +Tschukotsehja River eastward to Behring's Straits, in the eastern extremity +of Asia -- Cook's East Cape -- which, according to Beechey, is only 66 +degrees E.* + + +[footnote] *On the mean latitude of the Northern Asiatic shores, and the +true name of Cape Taimura (Cape Siewere-Wostotschnoi), and Cape Northeast +(Schalagskoi Mys), see Humboldt, 'Asie Centrale', t. iii., p. 35, 37. + + +The northern shore of the New Continent follows with tolerable exactness the +parallel of 70 degrees, since the lands to the north and south of Barrow's +Strait, from Boothia Felix and Victoria Land, are merely detached islands. + +The pyramidal configuration of all the southern extremities of continents +belongs to the 'similtudines physicae in configuratione mundi', to which +Bacon already called attention in his 'Novum Organon', and with which +Reinhold Foster, one of Cook's companions in his second voyage of +circumnavigation, connected some ingenious considerations. On looking +eastward from the meridian of Teneriffe, we perceive that the southern +extremities of the three continents, viz., Africa as the extreme +p 291 +of the Old World, Australia, and South America, successively approach nearer +toward the south pole. New Zealand, whose length extends fully 12 degrees +of latitude, forms an intermediate link between Australia and South America, +likewise terminating in an island, New Leinster. It is also a remarkable +circumstance that the greatest extension toward the south falls in the Old +Continent, under the same meridian in which the extremest projection toward +the north pole is manifested. This will be perceived on comparing the Cape +of Good Hope and the Lagullas Bank with the North Cape of Europe, and the +peninsula of Malacca with Cape Taimura in Siberia.* + + +[footnote] *Humboldt, 'Asie Centrale', t. i., p. 198-200. The southern +point of America, and the Archipelago which we call Terra del Fuego, lie in +the meridian of the northwestern part of Baffin's Bay, and of the great +polar land, whose limits have not as yet been ascertained, and which, +perhaps, belongs to West Greenland. + + +We know not whether the poles of the earth are surrounded by land or by a +sea of ice. Toward the north pole the parallel of 82 degrees 55' has been +reached, but toward the south pole only that of 78 degrees 10'. + +The pyramidal terminations of the great continents are variously repeated on +a smaller scale, not only in the Indian Ocean and in the peninsulas of +Arabia, Hindostan, and Malacca, but also, as was remarked by Eratosthenes +and Polybius, in the Mediterranean, where these writers had ingeniously +compared together the forms of the Iberian, Italian, and Hellenic +peninsulas.* + + +[footnote] *Strabo, lib. ii., p. 92, 108, Cassaub. + + +Europe, whose area is five times smaller than that of Asia, may almost be +regarded as a multifariously articulated western peninsula of the more +compact mass of the ontinent of Asia, the climatic relations of the former +being to those of the latter as the peninsula of Brittany is to the rest of +France. + + +[footnote] *Humboldt, 'Asie Centrale', t. iii., p. 25. As early as the +year 1817, in my work 'De distributione Geographica Plantarum, secundum +caels temperiem et altitudinem Montium', I directed attention to the +important influence of compact and of deeply-articulated continents on +climate and human civilization, "Regiones vel per sinus lunatos in longa +cornua porrectae, angulois littorum recessibus quasi membratim discerptae, +vel spatia patentia in immensum, quorum littora nullis incisa angulis ambit +sine aufractu oceanus" (p. 81, 182). On the relations of the extent of +coast to the area of a continent (considered in some degree as a measure of +the accessibility of the interior), see the inquiries in Berghaus, 'Annalen +der Erdkunde', bd. xii., 1835, s. 490, and 'Physikal. Atlas', 1839, No. +iii., s. 69. + + +The influence exercised by the articulation and higher development of the +form of a continent on the moral and intellectual condition of nations was +remarked by Strabo,* who extols +p 292 +the varied form of our small continent as a special advantage. + + + +[footnote] *Strabo, lib. ii., p. 92, 198. Casaub. + + +Africa* and South America, which manifest so great a resemblence in their +configuration, are also the two continents that exhibit the simplest +littoral outlines. + + +[footnote] *Of Africa, Pliny says (v. 1), "Nec alia pars terrarum paudiores +recipit sinus." The small Indian peninsula on this side the Ganges present, +in its triangular outline, a third analogous form. In ancient Greece there +prevailed an opinion of the regular configuration of the dry land. There +were four gulfs or bays, among which the Persian Gulf was placed in +opposition to the Hyrcanian or Caspian Sea (Arrian, vii., 16; Plut., 'in +vita Alexandri', cap. 44; Dionys. Perieg., v. 48 and 630, p. 11, 38, +Bernh.). These four bays and the isthmuses were, according to the optical +fancies of Agesianax, supposed to be reflected in the moon (Plut., 'de Facie +in Orbem Lunae', p. 921, 19). Respecting the 'terra quadrifida', or four +divisions of the dry land, of which two lay north and two south of the +equator, see Macrobius, 'Comm. in Somnium Scipionis', ii., 9. I have +submitted this portion of the geography of the ancients, regarding which +great confusion prevails, to a new and careful examination, in my 'Examen +Crit. de l'Hist. de la Geogr.', t. i., p. 119, 145, 180-185, as also in +'Asie Centr.', t. ii., p. 172-178. + + +It is only the eastern shores of Asia, which, broken as it were by the force +of the currents of the ocean* ('fractas ex aequore terra'), exhibit a +richly-variegated configuration, peninsulas and contiguous islands +alternating from the equator to 60 degrees north latitude. + + +[footnote] *Fleurieu, in 'Voyage de Marchand autour du Monde', t. iv., p. +38-42. + + +Our Atlantic Ocean presents all the indications of a valley. It is as if a +flow of eddying waters had been directed first toward the northeast, then +toward the northwest, and back again to the northeast. The parallelism of +the coasts north of 10 degrees south latitude, the projecting and receding +angles, the convexity of Brazil opposite to the Gulf of Guinea, that of +Africa under the same parallel, with the Gulf of the Antilles, all favor +this apparently speculative view.* + + +[footnote] *Humboldt, in the 'Journal de Physique', liii., 1799, p. 33; and +'Rel. Hist.', t. ii., p. 19; t. iii., p. 189, 198. + + +In this Atlantic valley, as is almost every where the case in the +configuration of large continental masses, coasts deeply indented, and rich +in islands, are situated opposite to those possessing a different character. + I long since drew attention to the geognostic importance of entering into a +comparison of the western coast of Africa and of South America within the +tropics. The deeply curved indentation of the African continent at Fernando +Po, 4 degrees 30' north latitude, is repeated on the coast of the Pacific at +18 degrees 15' south latitude, between the Valley of Arica and the Morro de +Juan Diaz, where the Peruvian coast suddenly changes the direction from +wouth to north which it had previously followed, and inclines to the +northwest. This change +p 293 +of direction extends in like manner to the chain of the Andes, which is +divided into two parallel branches affecting not only the littoral +portions,* but even the eastern Cordilleras. + + +[footnote] *Humboldt, in Poggendorf's 'Annalen der Physik', bd. xl., s. +171. On the remarkable fiord formation at the southeast end of America, see +Darwin's Journal ('Narrative of the Voyages of the Adventure and Beagle', +vol. iii.), 1839, p. 266. The parallelism of the two mountain chains is +maintained from 5 degrees north latitude. The change in the direction of +the coast at Arica appears to be in consequence of the altered course of the +fissure, above which the Cordillera of the Andes has been upheaved. + + +In the latter, civilization had its earliest seat in the South American +plateaux where the small Alpine lake of Titicaca bathes the feet of the +colossal mountains of Sorata and Illimani. Further to the south, from +Valdiva and Chiloë (40 degrees to 42 degrees south latitude), through the +Archipelago 'de los Chonos' to 'Terra del Fuego', we find repeated that +singular configuration of 'fiords' (a blending of narrow and deeply-indented +bays), which in the Northern hemisphere characterizes the western shores of +Norway and Scotland. + +These are the most general considerations suggested by the study of the +upper surface of our planet with reference to the form of continents, and +their expansion in a horizontal direction. We have collected facts and +brought forward some analogies of configuration in distant parts of the +earth, but we do not venture to regard them as fixed laws of form. When the +traveler on the declivity of an active volcano, as, for instance, of +Vesuvius, examines the frequent partial elevations by which portions of the +soil are often permanently upheaved several feet above their former level, +either immediately precediing or during the continuance of an eruption, thus +forming roof-like or flattened summits, he is taught how accidental +conditions in the expression of the force of subterranean vapors, and in the +resistance to be overcome, may modify the feeble perturbations in the +equilibrium of the internal elastic forces of our planet may have inclined +them more to its norther than to its southern direction, and caused the +continent in the eastern part of the globe to present a broad mass, whose +major axis is almost parallel with the equator, while in the western and +more oceanic part the southern extremity is extremely narrow. + +Very little can be empirically determined regarding the causal connection of +the phenomena of the formation of continents, or of the analogies and +contrasts presented by their +p 294 +configuration. All that we know regarding this subject resolves itself into +this one point, that the active cause is subterranean; that continents did +not arise at once in the form they now present, but were, as we have already +observed, increased by degrees by means of numerous oscillatory elevations +and depressions of the soil, or were formed by the fusion of separate +smaller continental masses. Their present form is, therefore, the result of +two causes, which have exercised a consecutive action the one on the other; +the first is the expression of subterranean force, whose direction we term +accidental, owing to our inability to defint it, from its removal from +within the sphere of our comprehension, while the second is derived from +forces acting on the surface, among which volcanic eruptions, the elevation +of mountains, and currents of sea water play the principal parts. How +totally different would be the condition of the temperature of the earth, +and consequently, of the state of vegetation, husbandry, and human society, +if the major axis of the New Continent had the same direction as that of the +Old Continent; if, for instance, the Cordilleras, instead of having a +southern direction, inclined from east to west; if there had been no +radiating tropical continent, like Africa, to the south of Europe; and if +the Mediterranean, which was once connected with the Caspian and Red Seas, +and which has become so powerful a means of furthering the +intercommunication of nations, had never existed, or if it had been elevated +like the plains of Lombardy and Cyrene? + +The changes of the reciprocal relations of height between the fluid and +solid portions of the earth's surface (changes which, at the same time, +determine the outlines of continents, and the greater or lesser submersion +of low lands) are to be ascribed to numerous unequally working causes. The +most powerful have incontestably been the force of elastic vapors inclosed +in the interior of the earth, the sudden change of temperature of certain +dense strata,* the unequal secular loss of +p 295 +heat experienced by the crust and nucleus of the earth, occasioning ridges +in the solid surface, local modifications of gravitation,** and, as a +consequence of these alterations, in the curvature of a portion of the +liquid element. + + +[footnote] *De la Beche, 'Sections and Views illustrative of Geological +Phenomena', 1830, tab. 40; Charles Babbage, 'Observations on the Temple of +Serapis at Pozzuoli, near Naples, and on certain Causes which may produce +Geological Cycles of great Extent', 1834. "If a stratum of sandstone five +miles in thickness should have its temperature raised about 100 degrees, its +surface would rise twenty-five feet. Heated beds of clay would, on the +contrary, occasion a sinking of the ground by their contraction." See +Bischof, 'Wurmelehre des Innern unseres Erdkorpers', s. 303, concerning the +calculations for the secular elevation of Sweden, on the supposition of a +rise by so small a quantity as 7 degrees in a stratum of about 155,000 feet +in thickness, and heated to a state of fusion. + + +[footnote] **The opinion so implicitly entertained regarding the +invariability of the force of gravity at any given point of the earth's +surface, has in some degree been controverted by the gradual rise of large +portions of the earth's surface. See Bessel, 'Ueber Maas und Gewicht', in +Schumacher's 'Jahrbuch fur' 1840, s. 134. + + +According to the views generally adopted by geognosists in the present day +and which are supported by the observation of a series of well-attested +facts, no less than by analogy with the most important volcanic phenomena, +it would appear that the elevation of continents is actual, and not merely +apparent or owing to the configuration of the upper surface of the sea. The +merit of having advanced this view beloongs to Leopold von Buch, the +narrative of his memorable 'Travels through Norway and Sweden' in 1806 and +1807.* + + + +[footnnote] *Th. ii. (1810), s. 389. See Hallstrom, in 'Kongl. +Vetenskaps-Academiens Handlingar' (Stockh.), 1823, p. 30; Lyell in the +'Philos. Trans.' for 1835; Blom (Amtmann in Budskerud), 'Stat. Beschr. von +Norwegen',1843, s. 89-116. If not before Von Buch's travels through +Scandinavia, at any rate before their publication, Playfair, in 1802, in his +illustrations of the Huttonian theory, § 393, and according to Keilhau ('Om +Landjardens Stigning in Norge', in the 'Nyt Magazine fur +Naturvidenskaberne'), and the Dane Jessen, even before the time of Playfair, +had expressed the opinion that it was not the sea which was sinking, but the +solid land of Sweden which was rising. Their ideas, however, were wholly +unknown to our great geologist, and exerted no influence on 'Norge +fremstillet efter dets naturlige og borgerlige Tilstand', Kjobenh., 1763, +sought to explain the causes of the changes in the relative levels of the +land and sea, basing his views on the early calculations of Celsius, Kalm, +and Dalin. He broaches some confused ideas regarding the possibility of an +internal growth of rocks, but finally declares himself in favor of an +upheaval of the land by earthquakes, "although," he observes, "no such +rising was apparent immediately after the earthquake of Egersund, yet the +earthquake may have opened the way for other causes producing such an +effect." + + +While the whole coast of Sweden and Finland, from Solvitzborg, on the limits +of Northern Scania, past Gefle to Tornea, and from Tornea to Abo, +experiences a gradual rise of four feet in a century, the southern part of +Sweden is, according to Neilson, undergoing a simultaneous depression.* + + +[footnote] *See Berzelius, 'Jahrsbericht uber die Fortschritte der +Physichen Wiss.', No. 18, s. 686. The islands of Saltholm, opposite to +Copenhagen, and Bjornholm, however, rise but very little -- Bjornholm +scarcely one foot in a century. See Forchhammer, in 'Philos. Magazine', 3d +Series, vol. ii., p. 309. + + +The maximum of this elevating +p 296 +force appears to be in the north of Lapland, and to diminish gradually to +the south toward Calmar and Solvitzborg. Lines marking the ancient level of +the sea in pre-historic times are indicated throughout the whole of Norway,* +from Cape Lindesnaes to the extremity of the North Cape, by banks of shells +identical with those of the present seas, and which have lately been most +accurately examined by Bravais during his long winter sojourn at Bosekop. + + +[footnote] *Keilhan, in 'Nyt Mag. fur Naturvid.', 1832, bd. i., p. 105-254; +bd. ii., p. 57; Bravais, 'Surles Lignes d'ancien Niveau de la Mer', 1843, p. +15-40. See, also, Darwin, "on the Parallel Roads of Glen-Roy and Lochaber," +in 'Philos. Trans. for' 1839, p. 60. + + +These banks lie nearly 650 feet above the present mean level of the sea, and +reappear, according to Keilhau and Eugene Robert, in a north-northwest +direction on the coasts of Spitzbergen, opposite the North Cape. Leopold +von Buch, who was the first to draw attention to the high banks of shells at +Tromsoe (latitude 69 degrees 40'), has, however, shown that the more ancient +elevations on the North Sea appertain to a different class of phenomena, +from the regular and gradual retrogressive elevations of the Swedish shores +in the Gulf of Bothnia. This latter phenomenon, which is well attested by +historical evidence, must not be confounded with the changes in the level of +the soil occasioned by earthquakes, as on the shores of Chili and of Cutch, +and which have recently given occasion to similar observations in other +countries. It has been found that a perceptible sinking resulting from a +disturbance of the strata of the upper surface sometimes occurs, +corresponding with an elevation elsewhere, as, for instance, in West +Greenland, according to Pingel and Graah, in Dalmatia and in Scania. + +Since it is highly probable that the oscillatory movements of the soil, and +the rising and sinking of the upper surface, were more strongly marked in +the early periods of our planet than at present, we shall be less surprised +to find in the interior of continents some few portions of the earth's +surface lying below the general level of existing seas. Instances of this +kind occur in the soda lakes described by General Andreossy, the small +bitter lakes in the narrow Isthmus of Suez, the Caspian Sea, the Sea of +Tiberias, and especially the Dead Sea.* + + +[footnote] *Humboldt, 'Asie Centrale', t. ii., p. 319-324; t. iii., p. +549-551. The depression of the Dead Sea has been successively determined by +the barometrical measurements of Count Berton, by the more careful ones of +Russegger, and by the trigonometrical survey of Lieutenant Symond, of the +Royal Navy, who states that the difference of level between the surface of +the Dead Sea and the highest houses of Jaffa is about 1605 feet. Mr. +Alderson, who communicated this result to the Geographical Society of London +in a letter, of the contents of which I was informed by my friend, Captain +Washington, was of opinion (Nov. 28, 1841) that the Dead Sea lay about 1400 +feet under the level of the Mediterranean. A more recent communication of +Lieutenant Symond (Jameson's 'Edinburgh New Philosophical Journal', vol. +xxxiv., 1843, p. 178) gives 1312 feet as the final result of two very +accordant trigonometrical operations. + + +The level of the water in the two last-named seas is +p 297 +666 and 1312 feet below the level of the Mediterranean. If we could +suddenly remove the alluvial soil which covers the rocky strata in many +parts of the earth's surface, we should discover how great a portion of the +rocky crust of the earth was then below the present level of the sea. The +periodic, although irregularly alternating rise and fall of the water of the +Caspian Sea, of which I have myself observed evident traces in the northern +portions of its basin, appears to prove,* as do also the observations of +Darwin on the coral seas,** that without earthquakes, properly so- called, +the surface of the earth is capable of the same gentle and progressive +oscillations as those which must have prevailed so generally in the earliest +ages, when the surface of the hardening crust of the earth was less compact +than at present. + + +[footnote] *'Sur la Mobilite du fond de la Mer Caspienne', in my 'Asie +Centr.', t. ii., p. 283-294. The Imperial Academy of Sciences of St. +Petersburgh in 1830, at my request, charged the learned physicist Lenz to +place marks indicating the mean level of the sea, for definite epochs, in +different places near Baku, in the peninsula of Abscheron. In the same +manner, in an appendix to the instructions given to Captain (now Sir James +C.) Ross for his Antarctic expedition, I urged the necessity of causing +marks to be cut in the rocks of the southern hemisphere, as had already been +done in Sweden and on the shores of the Caspian Sea. Had this measure been +adopted in the early voyages of Bougainville and Cook, we should now know +whether the secular relative changes in the level of the seas and land are +to be considered as a general, or merely a local natural phenomenon, and +whether a law of direction can be recognized in the points which have +simultaneous elevation or depression. + + +[footnote] **On the elevation and depression of the bottom of the South +Sea, and the diffrent areas of alternate movements, see Darwin's 'Journal', +p. 557, 561-566. + + +The phenomena to which we would here direct attention remind us of the +instability of the present order of things, and of the changes to which the +outlines and configuration of continents are probably still subject at long +intervals of time. That which may scarcely be perceptible in one +generation, accumulates during periods of time, whose duration is revealed +to us by the movement of remote heavenly bodies. The eastern coast of the +Scandinavian peninsula has probably risen +p 298 +about 320 feet in the space of 8000 years; and in 12,000 years, if the +movement be regular, parts of the bottom of the sea which lie nearest the +shores, and are in the present day covered by nearly fifty fathoms of water, +will come to the surface and constitute dry land. But what are such +intervals of time compared to the length of the geognostic periods revealed +to us in the stratified series of formations, and in the world of extinct +and varying organisms! We have hitherto only considered the phenomena of +elevation; but the analogies of observed facts lead us with equal justice to +assume the possibility of the depression of whole tracts of land. The mean +elevation of the non-mountainous parts of France amounts to less than 480 +feet. It would not, therefore, require any long period of time, compared +with the old geognostic periods, in which such great changes were brought +about in the interior of the earth, to effect the permanent submersion of +the northwestern part of Europe, and induce essential alterations in its +littoral relations. + +The depression and elevation of the solid or fluid parts of the earth -- +phenomena which are so opposite in their action that the effect of elevation +in one part is to produce an apparent depression in another -- are the +causes of all the changes which occur in the configuration of continents. +In a work of this general character, and in an impartial exposition of the +phenomena of nature, we must not overlook the 'possibility' of a diminution +of the quantity of water, and a constant depression of the level of seas. +Thgere can scarcely be a doubt that, at the period when the temperature of +the surface of the earth was higher, when the waters were inclosed in larger +and deeper fissures, and when the atmosphere possessed a totally different +character from what it does at present, great changes must have occurred in +the level of seas, depending upon the increase and decrease of the liquid +parts of the earth's surface. But in the actual condition of our planet, +there is no direct evidence of a real continuous increase or decrease of the +sea, and we have no proof of any gradual change in its level at certain +definite points of observation, as indicated by the mean range of the +barometer. According to experiments made by Daussy and Antonio Nobile, an +increase in the height of the barometer would in itself be attended by a +depression in the level of the sea. But as the mean pressure of the +atmosphere at the level of the sea is not the same at all latitudes, owing +to meteorological causes depending upon the direction of the wind and +varying degrees of moisture, the +p 299 +barometer alone can not afford a certain evidence of the general change of +level in the ocean. The remarkable fact that some of the ports in the +Mediterranean were repeatedly left dry during several hours at the beginning +of this century, appears to show that currents may by changes occurring in +their direction and force, occasion a 'local'' retreat of the sea, and a +permanent drying of a small portion of the shore, without being followed by +any actual diminution of water, or any permanent depression of the ocean. +We must, however, be very cautious in applying the knowledge which we have +lately arrived at, regarding these involved phenomena, since we might +otherwise be led to ascribe to water as the elder element, what ought to be +referred to the two other elements, earth and air. + +As the 'external' configuration of continents, which we have already +described in their horizontal expansion, exercises, by their variously +indented littoral outlines, a favorable influence on climate, trade, and the +progress of civilization, so likewise does their internal articulation, or +the vertical elevation of the soil (chains of mountains and elevated +plateaux), give rise to equally important results. Whatever produces a +polymorphic diversity of forms on the surface of our planetary habitation -- +such as mountains, lakes, grassy savannas, or even deserts encircled by a +band of forests -- impresses some peculiar character on the social condition +of the inhabitants. Ridges of high land covered by snow impede intercourse; +but a blending of low, discontinued mountain chains* and tracts of valleys, +as we see so happily presented in the west and south of Europe, tends to the +multiplication of meteorological processes and the products of vegetation, +and, from the variety manifested in different kinds of cultivation in each +district, even under the same degree of latitude, gives rise to wants that +stimulate the activity of the inhabitants. + + +[footnote] *Humboldt, 'Rel. Hist.', t. iii., p. 232-234. See also, the +able remarks on the configuration of the earth, and the position of its +lines of elevation in Albrechts von Roon, 'Grundzugen der Erd Volker und +Staatenkunde', Abth. i., 1837, s. 158, 270, 276. + + +Thus the awful revolutions, during which, by the action of the interior on +the crust of the earth, great mountain chains have been elevated by the +sudden upheaval of a portion of the oxydized exterior of our planet, have +served, after the establishment of repose, and on the revival of organic +life, to furnish a richer and more beautiful variety of individual forms, +and in a great measure to remove from the earth that aspect of dreary +p 300 +uniformity which exercises so impoverishing an influence on the physical and +intellectual powers of mankind. + +According to the grand views of Elie de Beaumont, we must ascribe a relative +age to each system of mountain chains* on the supposition that their +elevation must necessarily have occurred between the period of the +deposition of the vertically elevated strata and that of the horizontally +inclined strata running at the base of the mountains. + + +[footnnote] *Leop. von Buch, 'Ueber die Geognostischen Systeme von +Deutschland', in his 'Geogn. Briefen an Alexander von Humboldt', 1824, s. +265-271; Elie de Beaumont, 'Recherches sur les Revolutions de la Surface du +Globe', 1829, p. 297-307. + + +The ridges of the Earth's crust -- elevations of strata which are of the +same geognostic age -- appear, moreover, to follow one common direction. +The line of strike of the horizontal strata is not always parallel with the +axis of the chain, but intersects it, so that, according to my views,* the +phenomenon of elevation of the strata, which is even found to be repeated in +the neighboring plains, must be more ancient than the elevation of the chain. + + +[footnote] *Humboldt, 'Asie Centrale', t. i., p. 277-283. See, also my +'Essai sur le Gisement des Roches', 1822, p. 57, and 'Relat. Hist.', t. +iii., p. 244-250. + + +The main direction of the whole continent of Europe (from southwest to +northeast) is opposite to that of the great fissures which pass from +northwest to southeast, from the mouths of the Rhine and Elbe, through the +Adriatic and Red Seas, and through the mountain system of Putschi-Koh in +Luristan, toward the Persian Gulf and the Indian Ocean. This almost +rectangular intersection of geodesic lines exercises an important influence +on the commercial relations of Europe, Asia, and the northwest of Africa, +and on the progress of civilization on the formerly more flourishing shores +of the Mediterranean.* + + +[footnote] *'Asie Centrale', t. i., p. 284, 286. The Adriatic Sea likewise +follows a direction from S.E. to N.W. + + +Since grand and lofty mountain chains so strongly excite our imagination by +the evidence they afford of great terrestrial revolutions, and when +considered as the boundaries of climates, as lines of separation for waters, +or as the site of a different form of vegetation, it is the more necessary +to demonstrate, by a correct numerical estimation of their volume, how small +is the quantity of their elevated mass when compared with the area of the +adjacent continnents. The mass of the Pyrenees, for instance, the mean +elevation of whose summits, and the real quantity of whose base have been +ascertained by accurate measurements, would if scattered over +p 301 +the surface of France, only raise its mean level about 115 feet. The mass +of the eastern and western Alps would in like manner only increase the +height of Europe about 21 1/2 feet above its present level. I have found by +a laborious investigation,* which from its nature, can only give a maximum +limit, that the center of gravity of the volume of the land raised above the +present level of the sea in Europe and North America is respectively +situated at an elevation of 671 and 748 feet, while it is at 1132 and 1152 +feet in Asia and South America. + + +[footnote] *'De la hauteur Moyenne des Continents', in my 'Asie Centrale', +t. i., p. 82-90, 165-189. The results which I have obtained are to be +regarded as the extreme value ('nombres-limites'). Laplace's estimate of +the mean height of continents at 3280 feet is at least three times too high. + The immortal author of the 'Mecanique Celeste' (t. v., p. 14) was led to +this conclusion by hypothetical views as to the mean depth of the sea. I +have shown ('Asie Centr.', t. i., p. 93) that the old Alexandrian +mathematicians, on the testimony of Plutarch ('in Aemilio Paulo', cap. 15), +believed this depth to depend on the height of the mountains. The height of +the center of gravity of the volume of the continental masses is probably +subject to slight variations in the course of many centuries. + + +These numbers show the low level of norther regions. In Asia the vast +steppes of Siberia are compensated for by the great elevations of the land +(between the Himalaya, the North Thibetian chain of Kuen-lun, and the +Celestial Mountains), from 28 degrees 30' to 40 degrees north latitude. We +may, to a certain extent, trace in these numbers the portions of the Earth +in which the Plutonic forces were most intensely manifested in the interior +by the upheaval of continental masses. + +There are no reasons why these Plutonic forces may not, in future ages, add +new mountain systems to those which Elie de Beaumont has shown to be of such +different ages, and inclined in such different directions. Why should the +crust of the Earth have lost its property of being elevated in the ridges? +The recently-elevated mountain systems of the Alps and the Cordilleras +exhibit in Mont Blanc and Monte Rosa, in Sorata, Illimani, and Chimborazo, +colossal elevations which do not favor the assumption of a decrease in the +intensity of the subterranean forces. All geognostic phenomena indicate the +periodic alternation of activity and repose;* but the quiet we now enjoy is +only apparent. + + +[footnote] *'Zweiter Geologischer Brief von Elie de Beaumont an Alexander +von Humboldt', in Poggendorf's 'Annalen', bd. xxv., s. 1-58. + + +The tremblings which still agitate the surface under all latitudes, and in +every species of rock, the elevation of Sweden, the appearance of new +islands of eruption, are all conclusive as to the unquiet condition of our +planet. + +p 302 +The two envelopes of the solid surface of our planet -- the liquid and the +aeriform -- exhibit, owing to the mobility of their particles, their +currents, and their atmospheric relations, many analogies combined with the +contrasts which arise from the great difference in the condition of their +aggregation and elasticity. The depths of ocean and of air are alike +unknown to us. At some few places under the tropics no bottom has been +found with soundings of 276,000 (or more than four miles), while in the air, +if, according to Wollaston, we may assume that it has a limit from which +waves of sound may be reverberated, the phenomenon of twilight would incline +us to assume a height at least nine times as great.* + + +[footnote] *[See Wilson's Paper, 'On Wollaston's Argument from the +Limitation of the Atmosphere as to the finite Divisibility of Matter.' -- +'Trans. of the Royal Society of Edinb.', vol. xvi., p. 1, 1845.] -- Tr. + + +The aërial ocean rests partly on the solid earth, whose mountain chains and +elevated plateaux rise, as we have already seen, like green wooded shoals, +and partly on the sea, whose surface forms a moving base, on which rest the +lower, denser, and more saturated strata of air. + +Proceeding upward and downward from the common limit of the aërial and +liquid oceans, we find that the strata of air and water are subject to +determinate laws of decrease of temperature. This decrease is much less +rapid in the air than in the sea, which has a tendency under all latitudes +to maintain its temperature in the strata of water most contiguous to the +atmosphere, owing to the sinking of the heavier and more cooled particles. +A large series of the most carefully conducted observations on temperature +shows us that in the ordinary and mean condition of its surface, the ocean +from the equator to the forty-eighth degree of north and south latitude is +somewhat warmer than the adjacent strata of air.* + + +[footnnote[ *Hamboldt, 'Relation Hist.', t. iii., chap. xxix., p. 514-530. + + +Owing to this decrease of temperature at increasing depths, fishes and other +inhabitants of the sea, the nature of whose digestive and respiratory organs +fits them for living in deep water, may even, under the tropics, find the +low degree of temperature and the coolness of climate characteristic of more +temperate and more northern latitudes. This circumstance, which is +analogous to the prevalence of a mild and even cold air on the elevated +plains of the torrid zone, exercises a special influence on the migration +and geographical distribution of many marine animals. Moreover, the depths +at which fishes live, modify, by the increase of pressure, their cutaneous +respiration, and the +p 303 +oxygenous and nitrogenous contents of the swimming bladders. + +As fresh and salt water do not attain the maximum of their density at the +same degree of temperature, and as the saltness of the sea lowers the +thermometrical degree corresponding to this point, we can understand how the +water drawn from breat depths of the sea during the voyages of the Kotzebue +and Dupetit-Thouars could have been found to have only the temperature of 37 +degrees and 36.5 degrees. This icy temperatureof sea water, which is +likewise manifested at the depths of tropical seas, first led to a study of +the lower polar currents, which move from both poles toward the equator. +Without these submarine currents, the tropical seas at those depths could +only have a temperature equal to the local maximum of cold possessed by the +falling particles of water at the radiating and cooled surface of the +tropical sea. In the Mediterranean, the cause of the absence of such a +refrigeration of the lower strata is ingeniously explained by Arago, on the +assumption that the entrance of the deeper polar currents into the Straits +of Gibraltar, where the water at the surface flows in from the Atlantic +Ocean from west to east, is hindered by the submariine counter-currents +which move from east to west, from the Mediterranean into the Atlantic. + +The ocean, which acts as a general equalizer and moderator of climates, +exhibits a most remarkable uniformity and constancy of temperature, +especially between 10 degrees north and 10 degrees south latitude,* over +spaces of many thousands of square miles, at a distance from land where it +is not penetrated by currents of cold and heated water. + + +[footnote] *See the series of observations made by me in the South Sea, +from 8 degrees 5' to 13 degrees 16' N. lat., in my 'Asie Centrale', t. iii., +p. 234. + + +It has therefore, been justly observed, that an exact and long-continued +investigation of these thermic relations of the tropical seas might most +easily afford a solution to the great and much-contested problem of the +permanence of climates and terrestrial temperatures.* + + +[footnote] *We might (by means of the temperature of the ocean under the +tropics) enter into the consideration of a question which has hitherto +remained unanswered, namely, that of the constancy of terrestrial +temperatures, without taking into account the very circumscribed local +influences arising from the diminution of wood in the plains and on +mountains, and the drying up of lakes and marshes. Each age might easily +transmit to the succeeding one some few data, which would perhaps furnish +the most simple, exact, and direct means of deciding whether the sun, which +is almost the sole and exclusive source of the heat of our planet, changes +its physical constitution and splendor, like the greater number of the +stars, or whether, on the contrary, that luminary has attained to a +permanent condition." -- Arago, in the 'Comptes Rendus des Seances de +l'Acad. des Sciences', t. ii., p. 321, 327. + + +Great changes in the luminous disk of the sun would, +p 304 +if they were of long duration, be reflected with more certainty in the mean +temperature of the sea than in that of the solid land. + +The zones at which occur the maxima of the oceanic temperature and of the +density (the saline contents) of its waters, do not correspond with the +equator. The two maxima are separated from one another, and the waters of +the highest temperature appear to form two nearly parallel lines north and +south of the geographical equator. Lenz, in his voyage of circumnavigation, +found in the Pacific the maxima of density in 22 degrees north and 17 +degrees south latitude, while its minimum was situated a few degrees to the +south of the equator. In the region of calms the solar heat can exercise +but little influence on evaporation, because the stratum of air impregnated +with saline aqueous vapor, which rests on the surface of the sea, remains +still and unchanged. + +The surface of all connected seas must be considered as having a general +perfectly equal level with respect to their mean elevation. Local causes +(probably prevailing winds and currents) may, however, produce permanent, +although trifling changes in the level of some deeply indented bays, as for +instance, the Red Sea. The highest level of the water at the Isthmus of +Suez is at different hours of the day from 24 to 30 feet above that of the +Mediterranean. The form of the Straits of Bab-el-Mandeb, through which the +waters appear to find an easier ingress than egress, seems to contribute to +this remarkable phenomenon, which was known to the ancients.* + + +[[footnote] *Humboldt, 'Asie Centrale', t. ii., p. 321, 327. + + +The admirable geodetic operations of Coraboeuf and Delcrois show that no +perceptible difference of level exists between the upper surfaces of the +Atlantic and the Mediterranean, along the chain of the Pyrenees, or between +the coasts of northern Holland and Marseilles.* + + +[footnote] *See the numerical results in p. 328-333 of the volume just +named. From the geodesical levelings which, at my request, my friend +General Bolivar caused to be taken by Lloyd and Falmare, in the years 1828 +and 1829, it was ascertained that the level of the Pacific is at the utmost +3 1/2 feet higher than that of the Caribbean Sea; and even that at different +hours of the day each of the seas is in turn the higher, according to their +respective hours of flood and ebb. If we reflect that in a distance of 64 +miles, comprising 933 stations of observation, an error of three feet would +be very apt to occur, we may say that in these new operations we have +further confirmation of the equilibrium of the waters which communicate +round Cape Horn. (Arago, in the 'Annuaire du Bureau des Longitudes pour' +1831, p. 319.) I had inferred from barometrical observations instituted in +1799 and 1804, that if there were any difference between the level of the +Pacific and the Atlantic (Carribean Sea), it could not exceed three meters +(nine feet three inches). See my 'Relat. Hist.', t. iii., p. 555-557, and +'Annales de Chimie', t. i., p. 55-64. The measurements, which appear to +establish an excess of height for the waters of the Gulf of Mexico, and for +those of the northern part of the Adriatic Sea, obtained by combining the +trigonometrical operations of Delcrois and Choppin with those of the Swiss +and Austrian engineers, are open to many doubts. Notwithstanding the form +of the Adriatic, it is improbable that the level of its waters in its +northern portion should be 28 feet higher than that of the Mediterranean at +Marseilles, and 25 feet higher than the level of the Atlantic Ocean. See my +'Asie Centrale', t. ii., p. 332. + + +p 305 +Disturbances of equilibrium and consequent movements of the waters are +partly irregular and transitory, dependent upon winds, and producing waves +which sometimes, at a distance from the shore and during a storm, rise to a +height of more than 35 feet; partly regular and periodic, occasioned by the +position and attraction of the sun and moon, as the ebb and flow of the +tides; and partly permanent, although less intense, occurring as oceanic +currents. The phenomena of tides, which prevail in all seas (with the +exception of the smaller ones that are completely closed in, and where the +ebbing and flowing waves are scarcely or not at all perceptible), have been +perfectly explained by the Newtonian doctrine, and thus brought "within the +domain of necessary facts." Each of these periodically-recurring +oscillations of the waters of the sea has a duration of somewhat more than +half a day. Although in the open sea they scarcely attain an elevation of a +few feet, they often rise considerably higher where the waves are opposed by +the configuration of the shores, as for instance, at St. Malo and in Nova +Scotia, where they reach the respective elevation of 50 feet, and of 65 to +70 feet. "It has been shown by the analysis of the great geometrician +Laplace, that, supposing the depth to be wholly inconsiderable when compared +with the radius of the earth, the stability of the equilibrium of the sea +requires that the density of its fluid should be less than that of the +earth; and, as we have already seen, the earth's density is in fact five +times greater than that of water. The elevated parts of the land can not +therefore be overflowed, nor can the remains of marine animals found on the +summits of mountains have been conveyed to those localities by any previous +high tides.* + + +[footnote] *Bessel, 'Ueber Fluth und Ebbe', in Schumacher's 'ahrbuch', +1838, s. 225. + + +It is no slight + + + +This material taken from pages 305-362 + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p 305 [balance of p 305 is in file "09 Humboldt"] +It is no slight +p 306 +evidence of the importance of analysis, which is too often regarded with +contempt among the unscientific, that Laplace's perfect theory of tides has +enabled us, in our astronomical ephemerides, to predict the height of +spring-tides at the periods of new and full moon, and thus put the +inhabitants of the sea-shore on their guard against the increased danger +attending these lunar revolutions. + +Oceanic currents, which exercise so important an influence on the +intercourse of nations and on the climatic relations of adjacent coasts, +depend conjointly upon various causes, differing alike in nature and +importance. Among these we may reckon the periods at which tides occur in +their progress round the earth; the duration and intensity of prevailing +winds; the modifications of density and specific gravity which the particles +of water undergo in consequence of differences in the temperature and in the +relative quantity of saline contents at different latitudes and depths;* +and, lastly, the horary variations of the atmospheric pressure, successively +propagated from east to west, and occurring with such regularity in the +tropics. + + +[footnote] *The relative density of the particles of water depends +simultaneously on the temperature and on the amount of the saline contents +-- a circumstance that is not sufficiently borne in mind in considering the +cause of currents. The submarine current, which brings the cold polar water +to the equatorial regions, would follow an exactly opposite course, that is +to say, from the equator toward the poles, if the difference in saline +contents were alone concerned. In this view, the geographical distribution +of temperature and of density in the water of the ocean, under the different +zones of latitude and longitude, is of great importance. The numerous +observations of Lenz (Poggendorf's 'Annalen', bd. xx., 1830, s. 129), and +those of Captain Beechey, collected in his 'Voyage to the Pacific', vol. +ii., p. 727, deserve particular attention. See Humboldt, 'Relat. Hist.', t. +i., p. 74, and 'Asie Centrale', t. iii., p. 346. + + +These currents present a remarkable spectacle; like rivers of uniform +breadth, they cross the sea in different directions, while the adjacent +strata of water, which remain undisturbed, form, as it were, the banks of +these moving streams. This diffrence between the moving waters and those at +rest is most strikingly manifested where long lines of sea-weed, borne +onward by the current, enable us to estimate its velocity. In the lower +strata of the atmosphere, we may sometimes, during a storm, observe similar +phenomena in the limited aerial current, which is indicated by a narrow line +of trees, which are often found to be overthrown in the midst of a dense +wood. + +The general movement of the sea from east to west between +p 307 +the tropics (termed the equatorial or rotation currnt) is considered to be +owing to the propagation of tides and to the trade winds. Its direction is +changed by the resistance it experiences from the prominent eastern shores +of continents. The results recently obtained by Daussy regarding the +velocity of this current, estimated from observations made on the distances +traversed by bottles that had purposely been thrown into the sea, agree +within one eighteenth with the velocity of motion (10 French nautical miles, +952 toises each, in 24 hours) which I had found from a comparison with +earlier experiments.* + + +[footnote] *Humboldt, 'Relat. Hist.', t. i., p. 67; 'Nouvelles Annales des +Voyages', 1839, p. 255. + + +Christopher Columbus, during his third voyage, when he was seeking to enter +the tropics in the meridian of Teneriffe, wrote in his journal as follows:* +"I regard it as proved that the waters of the sea move from east to west, as +do the heavens ('las aguas van con los cielos'), that is to say, like the +apparent motion of the sun, moon, and stars." + + +[footnote] *Humboldt, 'Examen Crit. de l'Hist. de la Geogr.', t. iii., p. +100. Columbus adds shortly after (Navarrete, 'Coleccion de los Viages y +Descubrimientos de los Espanoles', t. i., p. 260), that the movement is +strongest in the Caribbean Sea. In fact, Rennell terms this region, "not a +current, but a sea in motion". ('Investigation of Currents', p. 23). 66-74. + + +The narrow currents, or true oceanic rivers which traverse the sea, bring +warm water into higher and cold water into lower latitudes. To the first +class belongs the celebrated Gulf Stream,* which was known to Anghiera, and +more especially to Sir Humphrey Gilbert in the sixteenth century. + + +[footnote] *Humboldt, 'Examen Critique', t. ii., p. 250; 'Relat. Hist.', t. +i., p. 66-74. + + +[footnote] *Petrus Martyr de Anghiera, 'De Rebus Oceanicis et Orbe Novo', +Bas., 1523, Dec. iii., lib. vi., p. 57. See Humboldt, 'Examen Critique', t. +ii., p. 254-257, and t. iii., p. 108. + + +Its first impulse and origin is to be sought to the south of the Cape of +Good Hope; after a long circuit it pours itself from the Caribbean Sea and +the Mexican Gulf through the Straits of the Bahamas, and, following a course +from south-southwest to north-northeast, continues to recede from the shores +of the United States, until, further deflected to the eastward by the Banks +of Newfoundland, it approaches the European coasts, frequently throwing a +quantity of tropical seeds ('Mimosa scandens, Guilandina bonduc, Dolichos +urens') on the shores of Ireland, the Hebrides, and Norway. The +northeastern prolongation tends to mitigate the cold of the ocean, and to +ameliorate the climate on the most northern extremity of Scandinavia. At +the point where the Gulf Stream +p 308 +is deflected from the Banks of Newfoundland toward the east, it sends off +branches to the south near the Azores.* + + +[footnote] *Humboldt, 'Examen Crit.', t. iii., p. 64-109 + + +This is the situation of the Sargasso Sea, or that great bank of weeds which +so vividly occupied the imagination of Christopher Columbus, and which +Oviedo calls the sea-weed meadows ('Praderias de yerva'). A host of small +marine animals inhabits these tently-moved and evergreen masses of 'Fucus +natans', one of the most generally distributed of the social plants of the +sea. + +The counterpart of this current (which in the Atlantic Ocean, between +Africa, America, and Europe, belongs almost exclusively to the northern +hemisphere) is to be found in the South Pacific, where a current prevails, +the effect of whose low temperature on the climate of the adjacent shores I +had an opportunity of observing in the autumn of 1802. It brings the cold +waters of the high southern latitudes to the coast of Chili, follows the +shores of this continent and of Peru, first from south to north, and is then +deflected from the Bay of Arica onward from south-southeast to +north-northwest. At certain seasons of the year the temperature of this +cold oceanic current is, in the tropics, only 60 degrees, while the +undisturbed adjacent water exhibits a temperature of 81.5 degrees and 83.7 +degrees. On that part of the shore of South America south of Payta, which +inclines furthest westward, the current is suddenly deflected in the same +direction from the shore, turning so sharply to the west that a ship sailing +northward passes suddenly from cold into warm water. + +It is not known to what depth cold and warm oceanic currents propagate their +motion; but the deflection experienced by the South African current, from +the Lagullas Bank, which is fully from 70 to 80 fathoms deep, would seem to +imply the existence of a far-extending propagation. Sand banks and shoals +lying beyond the line of these currents may, as was first discovered by the +admirable Benjamin Franklin, be recognized by the coldness of the water over +them. This depression of the temperature appears to me to depend upon the +fact that, by the propagation of the motion of the sea, deep waters rise to +the margin of the banks and mix with the upper strata. My lamented friend, +Sir Humphrey Davy, ascribed this phenomenon (the knowledge of which is often +of great practical utility in securing the safety of the navigator) to the +descent of the particles of water that had been cooled by nocturnal radiation +p 309 +and which remain nearer to the surface, owing to the hinderance placed in +the way of their greater descent by the intervention of sand-banks. By his +observations Franklin may be said to have converted the thermometer into a +sounding line. Mists are frequently found to rest over these depths, owing +to the condensation of the vapor of the atmosphere by the cooled waters. I +have seen such mists in the south of Jamaica, and also in the Pacific, +defining with sharpness and clearness the form of the shoals below them, +appearing to the eye as the aerial reflection of the bottom of the sea. A +still more striking effect of the cooling produced by shoals is manifested +in the higher strata of air, in a somewhat analogous manner to that observed +in the case of flat coral reefs, or sand islands. In the open sea, far from +the land, and when the air is calm, clouds are often observed to rest over +the spots where shoals are situated, and their bearing may then be taken by +the compass in the same manner as that of a high mountain or isolated peak. + +Although the surface of the ocean is less rich in living forms than that of +continents, it is not improbable that, on a further investigation of its +depths, its interior may be found to possess a greater richness of organic +life than any other portion of our planet. Charles Darwin, in the agreeable +narrative of his extensive voyages, justly remarks that our forests do not +conceal so many animals as the low woody regions of the ocean, where the +sea-weed rooted to the bottom of the shoals, and the severed branches of +fuci, loosened by the force of the waves and currents, and swimming free, +unfold their delicate foliage, upborne by air-cells.* + + +[footnote] *[See 'Structure and Distribution of Coral Reefs', by Charles +Darwin, London, 1842. Also, 'Narrative of the Surveying Voyage of H.M.S. +"Fly" in the Eastern Archipelago, during the Years ' 1842-1846, by J. B. +Jukes, Naturalist to the expedition, 1847.] -- Tr. + + +The application of the microscope increases, in the most striking manner, +our impression of the rich luxuriance of animal life in the ocean, and +reveals to the astonished senses a consciousness of the universality of +life. In the oceanic depths, far exceeding the height of our loftiest +mountain chains, every stratum of water is animated with polygastric +sea-worms, Cyclidiae and Ophrydinae. The waters swarm with countless hosts +of small luminiferous animalcules, Mammaria (of the order of Acalephae), +Crustacea, Peridinea, and circling Nereides, which when attracted to the +surface by peculiar meteorological conditions, convert every wave into a +foaming band of flashing light. + +p 310 +The abundance of those marine animalcules, and the animal matter yielded by +their rapid decomposition are so vast that the sea water itself becomes a +nutrient fluid to many of the larger animals. However much this richness in +animated forms, and this multitude of the most various and highly-developed +microscopic organisms may agreeably excite the fancy, the imagination is +even more seriously, and, I might say, more solemnly moved by the impression +of boundlessness and immeasureability, which are presented to the mind by +every sea voyage. All who possess an ordinary degree of mental activity, +and delight to create to themselves an inner world of thought, must be +penetrated with the sublime image of the infinite, when gazing around them +on the vast and boundless sea, when involuntarily the glance is attracted to +the distant horizon, where air and water blend together, and the stars +continually rise and set before the eyes of the mariner. This contemplation +of the eternal play of the elements is clouded, like every human joy, by a +touch of sadness and of longing. + +A peculiar predilection for the sea, and a grateful remenbrance of the +impression which it has excited in my mind, when I have seen it in the +tropics in the calm of nocturnal rest, or in the fury of the tempest, have +alone induced me to speak of the individual enjoyment afforded by its aspect +before I entered upon the consideration of the favorable influence which the +proximity of the ocean has incontrovertibly exercised on the cultivation of +the intellect and character of many nations, by the multiplication of those +bands which ought to encircle the whole of humanity, by affording additional +means of arriving at a knowledge of the configuration of the earth, and +furthering the advancement of astronomy, and of all other mathematical and +physical sciences. A portion of this influence was at first limited to the +Mediterranean and the shores of southwestern Africa, but from the sixteenth +century it has widely spread, extending to nations who live at a distance +from the sea, in the interior of continents. Since Columbus was sent to +"unchain the ocean"* (as the unknown voice whispered to him in a dream when +he lay on a sick-bed near +p 311 +the River Belem), man has ever boldly ventured onward toward the discovery +of unknown regions. + + +[footnote] *The voice addressed him in these words, "Maravillosamente Dios +hizo sonar tu nombre en la tierra; de los atamientos de la mar Oceana, que +estaban cerrados con cadenas tan fuertes, te dió las llaves" -- "God will +cause thy name to be wonderfully resounded through the earth, and give thee +the keys of the gates of the ocean, which are closed with strong chains." +The dream of Columbus is related in the letter to the Catholic monarchs of +July the 7th, 1503. (Humboldt, 'Examen Critique', t. iii., p. 234.) + + +The second external and general covering of our planet, the aerial ocean, in +the lower strata, and on the shoals of which we live, presents six classes +of natural phenomena, which manifest the most intimate connection with one +another. They are dependent on the chemical composition of the atmosphere, +the variations in its transparency, polarization, and color, its density or +pressure, its temperature and humidity, and its electricity. The air +contains in oxygen the first element of physical animal life, and besides +this benefit, it possesses another, which may be said to be of a nearly +equally high character, namely, that of conveying sound; a faculty by which +it likewise becomes the conveying sound; a faculty by which it likewise +becomes the conveyer of speech and the means of communicating thought, and +consequently of maintaining social intercourse. If the Earth were deprived +of an atmosphere, as we suppose our moon to be, it would present itself to +our imagination as a soundless desert. + +The relative quantities of the substances composing the strata of air +accessible to us have, since the beginning of the nineteenth century, become +the object of investigations, in which Gay-Lussac and myself have taken an +active part; it is however, only very recently that the admirable labors of +Dumas and Boussingault have, by new and more accurate methods, brought the +chemical analysis of the atmosphere to a high degree of perfection. +According to this analysis, a volume of dry air contains 20.8 of oxygen, and +79.2 of nitrogen, besides from two to five thousandth parts of carbonic acid +gas, a still smaller quantity of carbureted hydrogen gas,* and, according to +the important experiments of Saussure and Liebig, traces of ammoniacal +vapors,** from which plants derive their nitrogenous contents. + + +[footnote] *Boussingault, 'Recherches sur la Composition de l'Atmosphere', +in the 'Annales de Chimie et de Physique', t. lvii., 1834, p. 171-173; and +lxxi. 1839, p. 116. According to Boussingault and Lewy, the proportion of +carbonic acid in the atmosphere at Audilly, at a distance, therefore, from +the exhalations of a city, varied only between 0.00028 and 0.00031 in volume. + + +[footnote] **Liebig, in his important work, entitles 'Die Organische Chemie +in ihrer Anwendung auf Agricultur und Physiologie', 1840, s. 62-72. On the +influence of atmospheric electricity in the production of nitrate of +ammonia, which, coming into contact with carbonate of lime, is changed into +carbonate of ammonia, see Boussingault's 'Economie Rurale consideree dans +ses Rapports avec la Chimie et la Meteorologie', 1844, t. ii., p. 247, 267, +and t. i., p. 84. + + +Some observations of Lewy render it probable that the quantity of oxygen +varies perceptibly +p 312 +but slightly, over the sea and in the interior of continents, according to +local conditions or to the seasons of the year. We may easily conceive that +changes in the oxygen held in solution in the sea, produced by microscopic +animal organisms, may be attended by alterations in the strata of air in +immediate contact with it.* + + +[footnote] *Lewy, in the 'Comptes Rendus de l'Acad. des Sciences', t. +xvii., Part ii., p. 235-248. + + +The air which Martins collected at Faulhorn at an elevation of 8767 feet, +contained as much oxygen as the air at Paris.* + + +[footnote] *Dumas, in the 'Annales de Chimie, 3e Serie', t. iii., 1841, p. +257. + + +The admixture of carbonate of ammonia in the atmosphere may probably be +considered as older than the existence of organic beings on the surface of +the earth. The sources from which carbonic acid* may be yielded to the +atmosphere are most numerous. + + +[footnote] *In this enumeration, the exhalation of carbonic acid by plants +during the night, while they inhale oxygen, is not taken into account, +because the increase of carbonic acid from this source is amply +counter-balanced by the respiratory process of plants during the day. See +Boussingault's 'Econ. Rurale', t. i., p. 53-68, and Liebig's 'Organische +Chemie', s. 16, 21. + + +In the first place we would mention the respiration of animals, who receive +the carbon which they inhale from vegetable food, while vegetables receive +it from the atmosphere; in the next place, carbon is supplied from the +interior of the earth in the vicinity of exhausted volcanoes and thermal +springs, from the decomposition of a small quantity of carbureted hydrogen +gas in the atmosphere, and from the electric discharges of clouds, which are +of such frequent occurrence within the tropics. Besides these substances, +which we have considered as appertaining to the atmosphere at all heights +that are accessible to us, there are others accidentally mixed with them, +especially near the ground, which sometimes, in the form of miasmatic and +gaseous contagia, exercise a noxious influence on animal organization. +Their chemical nature has not yet been ascertained by direct analysis; but, +from the consideration of the processes of decay which are perpetually going +on in the animal and vegetable substances with which the surface of our +planet is covered, and judging from analogies deduced from the comain of +pathology, we are led to infer the existence of such noxious local +admixtures. Ammoniacal and other nitrogenous vapors, sulphureted hydrogen +gas, and compounds analogous to the polybasic ternary and quaternary +compounds analogous to the polybasic ternary and quaternary combinations of +the vegetable kingdom, may produce miasmata,* +p 313 +which, under various forms, may generate ague and typhus fever (not by any +means exclusively on wet, marshy ground, or on coasts covered by putrescent +mollusca, and low bushes of 'Rhizophora mangle' and Avicennia). + + +[footnote] *Gay-Lussac, in 'Annales de Chimie', t. liii., p. 120; Payen, +Mem. sur la Composition Chimique des Vegetaux, p. 36, 42; Liebig, 'Org. +Chemie', s. 229-345; Boussingault, 'Econ. Rurale', t. i., p. 142-153. + + +Fogs which have a peculiar smell at some seasons of the year, remind us of +these accidental admixtures in the lower strata of the atmosphere. Winds +and currents of air caused by the heating of the ground even carry up to a +considerable elevation solid substances reduced to a fine powder. The dust +which darkens the air for an extended area, and falls on the Cape Verd +Islands, to which Darwin has drawn attention, contains, according to +Ehrenberg's discovery, a host of silicious-shelled infusoria. + +As principal features of a general descriptive picture of the atmosphere, we +may enumerate: + +1. 'Variations of atmospheric pressure': to which belong the horary +oscillations, occurring with such regularity in the tropics, where they +produce a kind of ebb and flow in the atmosphere, which can not be ascribed +to the attraction of the moon,* and which differs so considerably according +to geographical latitude, the seasons of the year, and the elevation above +the level of the sea. + + +[footnote] *Bouvard, by the application of the formulae, in 1827, which +Laplace had deposited with the Board of Longitude shortly before his death, +found that the portion of the horary oscillations of the pressure of the +atmosphere, which depends on the attraction of the moon, can not raise the +mercury in the barometer at Paris more than the 0.018 of a millimeter, while +eleven years' observations at the same place show the mean barometric +oscillation, from 9 A.M. to 3 P.M., to be 0.756 millim., and from 3 P.M. to +9 P.M., 0.373 millim. See 'Memoires de l'Acad. des Sciences', t. vii., +1827, p. 267. + + +2. 'Climatic distribution of heat', which depends on the relative position +of the transparent and opaque masses (the fluid and solid parts of the +surface of the earth), and on the hypsometrical configuration of continents; +relations which determine the geographical position and curvature of the +isothermal lines (or curves of equal mean annual temperature) both in a +horizontal and vertical direction, or on a uniform plane, or in different +superposed strata of air. + +3. 'The distribution of the humidity of the atmosphere'. The quantitative +relations of the humitidy depend on the differences in the solid and oceanic +surfaces; on the distance from the equator and the level of the sea; on the +form in which the +p 314 +aqueous vapor is precipitated, and on the connection existing between these +deposits and the changes of temperature, and the direction and succession of +winds. + +4. 'The electric condition of the atmosphere'. the primary cause of this +condition, when the heavens are serene, is still much contested. Under this +head we must consider the relation of ascending vapors to the electric +charge and the form of the clouds, according to the different periods of the +day and year; the difference between the cold and warm zones of the earth, +or low and high lands; the frequency or rarity of thunder storms, their +periodicity and formation in summer and winter; the causal connection of +electricity, with the infrequent occurrence of hail in the night, and with +the phenomena of water and sand spouts, so ably investigated by Peltier. + +The horary oscillations of the barometer, which in the tropics present two +maxima (viz., at 9 or 9 1/4 P.M., and 4 A.M., occurring, therefore, in +almost the hottest and coldest hours), have long been the object of my most +careful diurnal and nocturnal observations.* + + +[footnote] *'Observations faites pour constater la Marche des Variations +Horaires du Barometre sous les Tropiques', in my 'Relation Historique du +Voyage aux Regions Equinoxiales', t. iii., p. 270-313. + + +Their regularity is so great, that, in the daytime especially, the hour may +be ascertained from the height of the mercurial column without an error, on +the average, of more than fifteen or seventeen minutes. In the torrid zones +of the New Continent, on the coasts as well as at elevations of nearly +13,000 feet above the level of the sea, where the mean temperature falls to +44.6 degrees, I have found the regularity of the ebb and flow of the aerial +ocean undisturbed by storms, hurricanes, rain, and earthquakes. The amount +of the daily oscillations diminishes from 1.32 to 0.18 French lines from the +equator to 70 degrees north latitude, where Bravais made very accurate +observations at Bosekop.* + + +[footnote] *Bravais, in Daemtz and Martins, 'Meteorologie', p. 263. At +Halle (51 degrees 29' N. lat.), the oscillation still amounts to 0.28 lines. + It would seem that a great many observations will be required in order to +obtain results that can be trusted in regard to the hours of the maximum and +minimum on mountains in the temperate zone. See the observations of horary +variations, collected on the Faulhorn in 1832, 1841, and 1842 (Martins, +'Meteorologie', p. 254.) + + +The supposition that, much nearer the pole, the height of the barometer is +really less at 10 A.M. than at 4 P.M., and consequently, that the maximum +and minimum influences of these hours +p 315 +are inverted, is not confirmed by Parry's observations at Port Bowen (73 +degrees 14'). + +The mean height of the barometer is somewhat less under the equator and in +the tropics, owing to the effect of the rising current,* than in the +temperate zones, and it appears to attain its maximum in Western Europe +between the parallels of 40 degrees and 45 degrees. + + +[footnote] *Humboldt, 'Essai sur la Geographie des Plantes', 1807, p. 90; +and in 'Rel. Hist.', t. iii., p. 313; and on the diminuation of atmospheric +pressure in the tropical portions of the Atlantic, in Poggend., 'Annalen der +Physik', bd. xxxvii., s. 245-258, and s. 463-486. + + +If with Kämtz we connect together by 'isobarometric' lines those places +which present the same mean difference between the monthly extremes of the +barometer, we shall have curves whose geographical position and inflections +yield important conclusions regarding the influence exercised by the form of +the land and the distribution of seas on the oscillations of the atmosphere. + Hindostan with its high mountain chains and triangular peninsulas, and the +eastern coasts of the New Continent, where the warm Gulf Stream turns to the +east at the Newfoundland Banks, exhibit greater isobarometric oscillations +than do the group of the Antilles and Western Europe. The prevailing winds +exercise a principal influence on the diminution of the pressure of the +atmosphere, and this, as we have already mentioned, is accompanied, +according to Daussey, by an elevation of the mean level of the sea.• + + +[footnote] *Dausay, in the 'Comptes Rendus', t. iii., p. 136. + + +As the most important fluctuations of the pressure of the atmosphere, +whether occurring with horary or annual regularity, or accidentally, and +then often attended by violence and danger,* are like all the other +phenomena of the weather, mainly owing to the heating force of the sun's +rays, it has long been suggested (partly according to the idea of Lambert) +that the direction of the wind should be compared with the height of the +barometer, alternations of temperature, and the increase and decrease of +humidity. + + +[footnote] *Dove, 'Ueber die Sturme', in Poggend., 'Annalen', bd. lii., s. +1. + + +Tables of atmospheric pressure during different winds, termed 'barometric +windroses', afford a deeper insight into the connection of meteorological +phenomena.* + + +[footnote] *Leopold von Buch, 'Barometrische Windrose', in 'Abhandl. der +Akad. der Wiss. zu Berlin aus den Jahren', 1818-1819, s. 187. + + +Dove has, with admirable sagacity, recognized, in the "law of rotation" in +both hemispheres, which he himself established, the cause of many important +processes in the aerial ocean.* + + +[footnote] *See Dove, 'Meteorologishe Untersuchungen', 1837, s. 99-313; and +the excellent observations of Kämtz on the descent of the west wind of the +upper current in high latitudes, and the general phenomena of the direction +of the wind, in his 'Vorlesungen uber µeterologie', 1840, s. 58-66, +196-200, 327-336, 353-364; and in Schumacher's 'Jahrbuch fur' 1838, s. +291-302. A very satisfactory and vivid representation of meteorological +phenomena is given by Dove, in his small work entitled +'Witterungsverhältnisse von Berlin', 1842. On the knowledge of the earlier +navigators of the rotation of the wind, see Churruca, 'Viage at Magellanes', +1793, p. 15; and on a remarkable expression of Columbus, which his son Don +Fernando Colon has presented to us in his 'Vida del Almirante', cap. 55, see +Humboldt, 'Examen Critique de l'Hist. de Geographie', t. iv., p. 253. + + +The difference of temperature between the +p 315 +equatorial and polar regions engenders two opposite currents in the upper +strata of the atmosphere and on the Earth's surface. Owing to the +difference between the rotatory velocity at the poles and at the equator, +the polar current is deflected eastward, and the equatorial current +westward. The great phenomena of atmospheric pressure, the warming and +cooling of the strata of air, the aqueous deposits, and even, as Dove has +correctly represented, the formation and appearance of clouds, alike depend +on the opposition of these two currents, on the place where the upper one +descends, and on the displacement of the one by the other. Thus the figures +of the clouds, which form an animated part of the charms of a landscape, +announce the processes at work in the upper regions of the atmosphere, and, +when the air is calm, the clouds will often present, on a bright summer sky, +the "projected image" of the radiating soil below. + +Where this influence of radiation is modified by the relative position of +large continental and oceanic surfaces, as between the eastern shore of +Africa and the western part of the Indian peninsula, its effects are +manifested in the Indian monsoons, which change with the periodic variations +in the sun's declination,* and which were known to the Greek navigators +under the name of 'Hippalos'. + + +[footnote] *'Monsun' (Malayan 'musim', the 'hippalos' of the Greeks) is +derived from the Arabic word 'mausim', a set time or season of the year, the +time of the assemblage of pilgrims at Mecca. The word has been applied to +the seasons at which certain winds prevail, which are, besides, named from +places lying in the direction from whence they come; thus, for instance, +there is the 'mausim' of Aden, of Guzerat, Malabar, etc. (Lassen, 'Indische +Alterthumskunde', bd. i., 1843, s. 211). On the contrasts between the solid +or fluid substrata of the atmosphere, see Dove, in 'Der Abhandl. der Akad. +der Wiss. zu Berlin aus dem Jahr' 1842, s. 239. + + +In the knowledge of the monsoons, which undoubtedly dates back thousands of +years among the inhabitants of Hindostan and China, of the eastern parts of +the Arabian Gulf and of the western shores of the Malayan +p 317 +Sea, and in the still more ancient and more general acquaintance with land +and sea winds, lies concealed, as it were, the germ of that meteorological +sciences which is now making such rapid progress. The long chain of +'magnetic stations' extending from Moscow to Pekin, across the whole of +Northern Asia, will prove of immense importance in determining the 'law of +the winds', since these stations have also for their object the +investigation of general meteorological relations. The comparison of +observations made at places lying so many hundred miles apart, will decide, +for instance, whether the same east wind blows from the elevated desert of +Gobi to the interior of Russia, or whether the direction of the Aerial +current first began in the middle of the series of the stations, by the +descent of the air from the higher regions. By means of such observations, +we may learn, in the strictest sense, 'whence' the wind cometh. If we only +take the results on which we may depend from those places in which the +observations on the direction of the winds have been continued more than +twenty years, we shall find (from the most recent and careful calculations +of Wilhelm Mahlmann) that in the middle latitudes of the temperate zone, in +both continents, the prevailing aerial current has a west-southwest +direction. + +Our insight into the 'distribution of heat' in the atmosphere has been +rendered more clear since the attempt has been made to connect together by +lines those places where the mean annual summer and winter temperatures have +been ascertain by correct observations. The system of 'isothermal, +osotheral' and 'isochimenal' lines, which I first brought into use in 1817, +may, perhaps, if it be gradually perfected by the united efforts of +investigators, serve as one of the main foundations of 'comparative +climatology'. Terrestrial magnetism did not acquire a right to be regarded +as a science until partial results were graphically connected in a system of +lines of 'equal declination, equal inclinatiion', and 'equal intensity'. + +The term 'climate', taken in its most general sense, indicated all the +changes in the atmosphere which sensibly affect our organs, as temperature, +humidity, variations in the barometrical pressure, the calm state of the air +or the action of opposite winds, the amount of electric tension, the purity +of the atmosphere or its admixture with more or less noxious gaseous +exhalations, and, finally, the degree of ordinary transparency and clearness +of the sky, which is not only important with respect to the increased +radiation from the Earth, the organic development of plants, and the +ripening of fruits, but +p 318 +also with reference to its influence on the feelings and mental condition of +men. + +If the surface of the Earth consisted of one and the same homogeneous fluid +mass, or of strata of rock having the same color, density, smoothness, and +power of absorbing heat from the solar rays, and of radiating it in a +similar manner through the atmosphere, the isothermal, isotheral, and +isochimenal lines would all be parallel to the equator. In this +hypothetical condition of the Earth's surface, the power of absorbing and +emitting light and heat would every where be the same under the same +latitudes. The mathematical consideration of climate, which does not +exclude the supposition of the existence of currents of heat in the +interior, or in the external crust of the earth, nor of the propagation of +heat by atmospheric currents, proceeds from this mean, and, as it were, +primitive condition. Whatever alters the capacity for absorption and +radiation, at places lying under the same parallel of latitude, gives rise +to inflections in the isothermal lines. The nature of these inflections, +the angles at which the isothermal, isotheral, or isochimenal lines +intersect the parallels of latitude, their convexity or concavity with +respect to the pole of the same hemisphere, are dependent on causes which +more or less modify the temperature under different degrees of longitude. + +The progress of 'Climatology' has been remarkably favored by the extension +of European civilization to two opposite coasts, by its transmission from +our western shores to a continent which is bounded on the east by the +Atlantic Ocean. When, after the ephemeral colonization from Iceland and +Greenland, the British laid the foundation of the first permanent +settlements on the shores of the United States of America, the emigrants +(whose numbers were rapidly increased in consequence either of religious +persecution, fanaticism, or love of freedom, and who soon spread over the +vast extent of territory lying between the Carolinas, Virginia, and the St. +Lawrence) were astonished to find themselves exposed to an intensity of +winter cold far exceeding that which prevailed in Italy, France, and +Scotland, situated in corresponding parallels of latitude. But, however +much a consideration of these climatic relations may have awakened +attention, it was not attended by any practical results until it could be +based on the numerical data of 'mean annual temperature'. If, between 58 +degrees and 30 degrees north latitude, we compair Nain, on the coast of +Labrador, with Gottenburg; Halifax with Bordeaus; New +p 319 +York with Naples; St. Augustine, in Florida, with Cairo, we find that, under +the same degrees of latitude, the differences of the mean annual temperature +between Eastern America and Western Europe, proceeding from north to south, +are successively 20.7 degrees, 13.9 degrees, 6.8 degrees, and almost 0 +degrees. The gradual decrease of the differences in this series extending +over 28 degrees of latitude is very striking. Further to the south, under +the tropics, the isothermal lines are every where parallel to the equator in +both hemispheres. We see, from the above examples, that the questions often +asked in society, how many degrees America (without distinguishing between +the eastern and western shores) is colder than Europe? and how much the mean +annual temperature of Canada and the United States is lower than that of +corresponding latitudes in Europe? are, when thus 'generally expressed', +devoid of meaning. There is a separate difference for each parallel of +latitude, and without a special comparison of the winter and summer +temperatures of the opposite coasts, it will be impossible to arrive at a +correct idea of climatic relations, in their influence on agriculture and +other industrial pursuits, or on the individual comfort or discomfort of +manking in general. + +In enumerating the causes which produce disturbances in the form of the +isothermal lines, I would distinguish between those which 'raise' and those +which 'lower' the temperature. To the first class belong the proximity of a +western coast in the temperate zone; the divided configuration of a +continent into peninsulas, with deeply-indented bays and inland seas; the +aspect of the position of a portion of the land with reference either to a +sea of ice spreading far into the polar circle, or to a mass of continental +land of considerable extent, lying in the same meridian, either under the +equator, or, at least, within a portion of the tropical zone; the prevalence +of southerly or westerly winds on the western shore of a continent in the +temperate northern zone; chains of mountains acting as protecting salls +against the winds coming from colder regions; the infrequency of swamps, +which, in the spring and beginning of summer, long remain covered with ice, +and the absence of woods in a dry, sandy soil; finally the constant serenity +of the sky in the summer months, and the vicinity of an oceanic current, +bringing water which is of a higher temperature than that of the surrounding +sea. + +Among the causes which tend to 'lower' the mean annual temperature I include +the following: elevation above the level of the sea, when not forming part +of an extended plain; the +p 320 +vicinity of an eastern coast in high and middle latitudes; the compact +configuration of a continent having no littoral curvatures or bays; the +extension of land toward the poles into the region of perpetual ice, without +the intervention of a sea remaining open in the winter; a geographical +position, in which the equatorial and tropical regions are occupied by the +sea, and consequently, the absence, under the same meridian, of a +continental tropical land having a strong capacity for the absorption and +radiation of heat; mountain chains, whose mural form and direction impede +the access of warm winds, the vicinity of isolated peaks, occasioning the +descent of cold currents of air down their declivities; extensive woods, +which hinder the isolation of the soil by the vital activity of their +foliage, which produces great evaporation, owing to the extension of these +organs, and increases the surface that is cooled by radiation, acting +consequently in a three-fold manner, by shade, evaporation, and radiation; +the frequency of swamps or marshes, which in the north form a kind of +subterranean glacier in the plains, lasting till the middle of the summer; a +cloudy summer sky, which weakens the action of the solar rays; and, finally, +a very clear winter sky, favoring the radiation of heat.* + + +[footnote] *Humboldt, 'Recherches sur les Causes des Inflexions des Lignes +Isothermes', in 'Asie Centr.', t. iii., p. 103-114, 118, 122, 188. + + +The simultaneous action of these disturbing causes, whether productive of an +increase or decrease of heat, determines, as the total effect, the +inflection of the isothermal lines, especially with relation to the +expansion and configuration of solid continental masses, as compared with +the liquid oceanic. These perturbations give rise to convex and concave +summits of the isothermal curves. There are, however, different orders of +disturbing causes, and each one must, therefore, be considered separately, +in order that their total effect may afterward be investigated with +reference to the motion (direction, local curvature) of the isothermal +lines, and the actions by which they are connected together, modified, +destroyed, or increased in intensity, as manifested in the contact and +intersection of small oscillatory movements. Such is the method by which, I +hope, it may some day be possible to connect together, by empirical and +numerically expressed laws, vast series of apparently isolated facts, and to +exhibit the mutual dependence which must necessarily exist among them. + +The trade winds -- easterly winds blowing within the tropics -- give rise, +in both temperate zones, to the west, or west-southwest +p 321 +sinds which prevail in those regions, and which are land winds to eastern +coasts, and sea winds to western coasts, estending over a space which, from +the great mass and the sinking of its cooled particles, is not capable of +any considerable degree of cooling, and hence it follows that the east winds +of the Continent must be cooler than the west winds, where their temperature +is not affected by the occurrence of oceanic currents near the shore. +Cook's young companion on his second voyage of circumnavigation, the +intelligent George Forster, to whom I am indebted for the lively interest +which prompted me to undertake distant travels, was the first who drew +attention, in a definite manner, to the climatic differences of temperature +existing in the eastern and western coasts of both continents, and to the +similarity of temperature of the western coast of North America in the +middle latitudes, with that of Western Europe.* + + +[footnote] *George Forster, 'Klein Schriften', th. iii., 1794, s. 87; Dove, +in Schumacher's 'Jahrbuch fur', s. 289; Kämtz, 'Meteorologie', bd. ii., s. +41, 43, 67, and 96; Arago, in the 'Comptes Rendus', t. i., p. 268. + + +Even in northern latitudes exact observations show a striking difference +between the 'mean annual temperature' of the east and west coasts of +America. The mean annual temperature of Nain, in (lat. 57 degrees 10'), +is fully 6.8 degrees 'below' the freezing point, while on the northwest +coast, at New Archangel, in Russian America (lat. 57 degrees 3'), it is 12.4 +degrees 'above' this point. At the first-named place, the mean summer +temperature hardly amounts to 43 degrees, while at the latter place it is 57 +degrees. Pekin (39 degrees 54'), on the eastern coast of Asia, has a mean +annual tempeerature of 52.8 degrees, which is 9 degrees below that of +Naples, situated somewhat further to the north. The mean winter temperature +of Pekin is at least 5.4 degrees below the freezing point, while in Western +Europe, even at Paris (48 degrees 50'), it is nearly 6 degrees above the +freezing point. Pekin has also a mean winter cold which is 4.5 degrees +lower than that of Copenhagen, lying 17 degrees further to the north. + +We have already seen the slowness with which the great mass of the ocean +follows the variations of temperature in the atmosphere, and how the sea +acts in equalizing temperatures, moderating simultaneously the severity of +winter and the heat of summer. Hence arises a second more important +contrast -- that, namely, between insular and littoral climates enjoyed by +all articulated continents having deeply indented bays and peninsulas, and +between the climate of the interior of great masses of solid land. This +remarkable contrast has been fully +p 322 +developed by Leopold von Buch in all its various phenomena, both with +respect to its influence on vegetation and agriculrure, on the transparency +of the atmosphere, the radiation of the soil, and the elevation of the line +of perpetual snow. In the interior of the Asiatic Continent, Tobolsk, +Barnaul on the Oby, and Irkutsk, have the same mean summer heat as Berlin, +Munster, and Cherbourg in Normandy, the thermometer sometimes remaining for +weeks together at 86 degrees or 88 degrees, while the mean winter +temperature is, during the coldest month, as low as -0.4 degrees to -4 +degrees. These continental climates have therefore justly been termed +'excessive' by the great mathematician and physicist Buffon; and the +inhabitants who live in countries having such 'excessive' climates seem +almost condemned, as Dante expresses himself, +"A sofferir tormenti caldi e geli."* + + +[fiitbite] *Dante, 'Divina Commedia, Purgatorio', canto iii. + + +In no portion of the earth, neither in the Canary Islands, in Spain, nor in +the south of France, have I ever seen more luxuriant fruit, especially +grapes, than in Astrachan, near the shores of the Caspian Sea (46 degrees +21'). Although the mean annual temperature is about 48ºdegrees, the mean +summer heat rises to 70ºdegrees, as at Bordeaux, while not only there, but +also further to the south, as at Kislar on the mouth of the Terek (in the +latitude of Avignon and Rimini), the thermometer sinks in the winter to -13 +degrees or -22 degrees. + +Ireland, Guernsey, and Jersey, the peninsula of Brittany, the coasts of +Normandy, and of the south of England, present, by the mildness of their +winters, and by the low temperature and clouded sky of their summers, the +most striking contrast to the continental climate of the interior of Eastern +Europe. In the northeast of Ireland (54 degrees 56'), lying under the same +parallel of latitude as Konigsberg in Prussia, the myrtle blooms as +luxuriantly as in Portugal. The mean temperature of the month of August, +which in Hungary rises to 70 degrees, scarcely reaches 61 degrees at Dublin, +which is situated on the same isothermal line of 49 degrees; the mean winter +temperature, which falls to about 28 degrees at Pesth, is 40 degrees at +Dublin (whose mean annual temperature is not more than 49 degrees); 3.6 +degrees higher than that of Milan, Pavia, Padua, and the whole of Lombardy, +where the mean annual temperature is upward of 55ºdegrees. At Stromness, +in the Orkneys, scarcely half a degree further south than Stockholm, the +winter temperature is 39 degrees, and consequently higher than that of +Paris, and neary as high as that of London. +p 323 +Even in the Faroe Islands, at 62 degrees latitude, the inland waters never +freeze, owing to the favoring influence of the west winds and of the sea. +On the charming coasts of Devonshire, near Salcombe Bay, which has been +termed, on account of the mildness of its climate, the 'Montpellier of the +North', the Agave Mexicana has been seen to blossoom in the open air, while +orange-trees trained against espaliers, and only slightly protected by +matting, are found to bear fruit. There, as well as at Penzance and +Gosport, and at Cherbourg on the coast of Normandy, the mean winter +temperature exceeds 42 degrees, falling short by only 2.4 degrees of the +mean winter temperature of Montpellier and Florence.* + + +[footnote] *Humboldt, 'Sur les Lignes Isothermes', in the 'Memoires de +Physique et de Chimie de la Societe d'Arcueil', t. iii., Paris, 1817, p. +143-165; Knight, in the 'Transactions of the Horticultural Society of +London', vol. i, p. 32; Watson, 'Remarks on the Geographical Distribution of +British Plants', 1835, p. 60; Trevelyan, in Jemieson's 'Edinburgh New Phil. +Journal', No. 18, p. 154; Mahlmann in his admirable German translation of my +'Asie Centrale', th. ii., s. 60. + + +These observations will suffice to show the important influence exercised on +vegetation and agriculture, on the cultivation of fruit, and on the comfort +of mankind, by differences in the distribution of the same mean annual +temperature, through the different seasons of the year. + +The lines which I have termed 'Isochimenal' and 'isotheral' (lines of equal +winter and equal summer temperature) are by no means parallel with the +'isothermal' lines (lines of equal annual temperature). If, for instance, +in countries where myrtles grow wild, and the earth does not remain covered +with snow in the winter, the temperature of the summer and autumn is barely +sufficient to bring apples to perfect ripeness, and if, again, we observe +that the grape rarely attains the ripeness necessary to convert it into +wine, either in islands or in the vicinity of the sea, even when cultivated +on a western coast, the reason must not be sought only in the low degree of +summer heat, indicated, in littoral situations, by the thermometer when +suspended in the shade, but likewise in another cause that has not hitherto +been sufficiently considered, although it exercises an active influence on +many other phenomena (as, for instance, in the inflammation of a mixture of +chlorine and hydrogen), namely the difference between direct and diffused +light, or that which prevails when the sky is clear and when it is overcast +by mist. I long since endeavored to attract the attention of physicists and +physiologists* to this +p 324 +difference, and to the 'unmeasured' heat which is locally developed in the +living vegetable cell by the action of direct light. + + +[footnote] *"Haec de temperie aeris, qui terram late circumfundit, ac in +quo, longe a solo, instrumenta nostra meteorologica suspensa habemus. Sed +alia est caloris vis, quem radii solis nullis nubibus velati, in foliis +ipsia et fructibus maturescentibus, magis minusve coloratis, gignunt, +quemque, ut egregia demonstrant experimenta amicissimorum Gay-Lussacii et +Thenardi de combustione chlori et hydrogenis, ope thermometri metiri nequis. + Etenim locis planis et montanis, vento libe spirante, circumfusi aeris +temperies cadem esse potest coelo sudo vel nebuloso; ideoque ex +observationibus solis thermometricis, nullo adhibito Photometro, haud +cognosces, quam ob causam Galliae septentrionalis tractur Armoricanus et +Nervicus, versus littora, coe temperato sed sole raro utentia, Vitem fere +non tolerant. Egent enim stirpes non solum caloris stimulo, sed et lucis, +quae magis intensa locis excelsis quam planis, duplici modo plantas movet, +vi sua tum propria, tum calorem in superficie earum excitante." -- Humboldt, +'De Distributione Geographica Plantarum', 1817, p. 163-164. + + +If, in forming a thermic scale of different kinds of cultivation,* we begin +with those plants which require the hottest climate, as the vanilla, the +cacao, banana, and cocoa-nut, and proceed to the pine-apples, the +sugar-cane, coffee, fruit-bearing date-trees, the cotton-tree, citrons, +olives, edible chestnuts, and fines producing potable wine, an exact +geographical consideration of the limits of cultivation, both on plains and +on the declivities of mountains, will teach us that other climatic relations +besides those of mean annual temperature are involved in these phenomena. + + +[footnote] *Humboldt, op. cit., p. 156-161; Meyen, in his 'Grundriss der +Pflanzengeographie', 1836 s. 379-467; Boussingault, 'Economie Rurale', t. +ii., p. 675. + + +Taking an example, for instance, from the cultivation of the vine, we find +that, in order to procure 'potable' wine,* it is requisite that the mean +annual heat should exceed 49 degrees, that the winter temperature upward of +64 degrees. + +[footnote] *the following table illustrates the cultivation of the vine in +Europe, and also the depreciation of its produce according to climatic +relations. See my 'Asie Centrale', t. iii., p. 159. The examples quoted in +the text for Bordeaux and Potsdam are, in respect of numerical relation, +alike applicable to the countries of the Rhine and Maine (48 degrees 35' to +40 degrees 7' N. lat.). Cherbourg in Normandy, and Ireland, show in th most +remarkable manner how, with thermal relations very nearly similar to those +prevailing in the interior of the Continent (as estimated by the thermometer +in the shade), the results are nevertheless extremely different as regards +the ripeness or the unripeness of the fruit of the vine, this difference +undoubtedly depending on the circumstance whether the vegetation of the +plant proceeds under a bright sunny sky, or under a sky that is habitually +obscured by clouds: + +[NB Table will line up in Courier 10 point] + +_____________________________________________________________________ +Places. Lat- Ele- Mean Win- Spring. Sum- Aut- Number of the + it- va- of the ter. mer. umn. years of the + tude tion. Year. observation + +_____________________________________________________________________ + deg ' Eng.ft. Fahr. + +Bordeaux 44 50 25.6 57.0 43.0 56.0 71.0 58.0 10 +Stras- 48 35 479.0 49.6 34.5 50.0 64.6 50.0 35 +bourg +Heid- 49 24 333.5 59.5 34.0 50.0 64.3 49.7 20 +elberg +Manheim 49 29 300.5 50.6 34.6 50.8 67.1 49.5 12 +Wurzburg 49 48 562.5 50.2 35.5 50.5 65.7 49.4 27 +Frank- +fort on +Maine 50 7 388.5 49.5 33.3 50.0 64.4 49.4 19 +Berlin 52 31 102.3 47.5 31.0 46.6 63.6 47.5 23 +Cher- +bourg (no +wine) 49 39 .... 52.1 41.5 50.8 61.7 54.2 3 +Dublin +(ditto) 53 23 .... 49.1 40.2 47.1 59.6 49.7 13 +___________________________________________________________________ + +The great accordance in the distribution of the annual temperature through +the different seasons, as presented by the results obtained for the valleys +of the Rhine and Maine, tends to confirm the accuracy of these +meteorological observations. The months of December, January, and February +are reckoned as winter months. When the different qualities of the wines +produced in Franconia, and in the countries around the Baltic, are compared +with the mean summer and autumn temperature of Wurzburg and Berlin, we are +almost surprised to find a difference of only about two degrees. The +difference in the spring is about four degrees. The influence of late May +frosts on the flowering season, and after a correspondingly cold winter, is +almost as important an element as the time of the subsequent ripening of the +grape. The difference alluded to in the text between the true temperature +of the surface of the ground and the indications of a thermometer suspended +in the shade and protected from extraneous influences, is inferred by Dove +from a consideration of the results of fifteen years' observations made at +the Chiswick Gardens. See Dove, in 'Bericht uber die Verhandl. der Berl. +Akad. der Wiss.', August, 1844, s. 285. + + +At Bordeaux, in the valley of the Garonne (44 degrees 50' lat.), the mean +annual winter, summer, and autumn temperatures are respectively 57 degrees, +43 degrees, 71 degrees, and 58 degrees. In the plains near the +p 325 +Baltic (52 degrees 30' lat.), where a wine is produced that can scarcely be +considered potable, these numbers are as follows: 47.5 degrees, 30 degrees, +63.7 degrees, and 47.5 degrees. If it should appear strange that the great +differences indicated by the influence of climate on the production of wine +should not be more clearly manifested by our thermometers, the circumstance +will appear less singular when we remember that a thermometer standing in +the shade, and protected from the effect of direct insolation and nocturnal +radiation can not, at all seasong of the year, and during all periodic +changes of heat, indicate the true superficial temperature of the ground +exposed to the whole effect of the sun's rays. + +The same relations which exist between the equable littoral climate of the +peninsula of Brittany, and the lower winter and +p 326 +higher summer temperature of the remainder of the continent of France, are +likewise manifested in some degree, between Europe and the great continent +of Asia, of which the former may be considered to constitute the western +peninsula. Europe owes its milder climate, in the first place, to its +position with respect to Africa, whose wide extent of tropical land is +favorable to the ascending current, while the equatorial region to the south +of Asia is almost wholly oceanic; and next to its deeply-articulated +configuration, to the vicinity of the ocean on its western shores; and, +lastly, to the existence of an open sea, which bounds its northern confines. + Europe would therefore become colder* if Africa were to be overflowed by +the ocean; of if the mythical Atlantis were to arise and connect Europe with +North America; or if the Gulf Stream were no longer to diffuse the warming +influence of its waters into the North Sea; or if, finally, another mass of +solid land should be upheaved by volcanic action, and interposed between the +Scandinavian peninsula and Spitzbergen. + + +[footnote] *See my memoir, 'Ueber die Haupt-Ursachen der +Temperaturverschiedenheit auf der Erdoberfläche', in the 'Abhandl. der +Akad. der Wissensch. zu Berlin von dem Jahr' 1827, s. 311. + + +If we observe that in Europe the mean annual temperature falls as we +proceed, from west to east, under the same parallel of latitude, from the +Atlantic shores of France through Germany, Poland, and Russia, toward the +Uralian Mountains, the main cause of this phenomenon of increasing cold must +be sought in the form of the continent (which becomes less indented, and +wider, and more compact as we advance), in the increasing distance from +seas, and in the diminished influence of westerly winds. Beyond the Uralian +Mountains these winds are converted into cool land-winds, blowing over +extended tracts covered with ice and show. The cold of western Siberia is +to be ascribed to these relations of configuration and atmospheric currents, +and not -- as Hippocrates and Trogus Pompeius, and even celebrated travelers +of the eighteenth century conjectures -- to the great elevation of the soil +above the level of the sea.* + + +[footnote] *The general level of Siberia, from Tobolsk, Tomsk, and Barnaul, +from the Altai Mountains to the Polar Sea, is not so high as that of Mauheim +and Dresden; indeed, Irkutsk, far to the east of the Jenisei, is only 1330 +feet above the level of the sea, or about one third lower than Munich. + + +If we pass from the differences of temperature manifested in the plains to +the inequalities of the polyhedric form of the surface of our planet, we +shall have to consider mountains either in relation to their influence on +the climate of neighboring +p 327 +valleys, or according to the effects of the hyposometrical relations on +their own summits, which often spread into elevated plateaux. The division +of mountains into chains separates the earth's surface into different +basins, which are often narrow and walled in, forming caldron-like valleys, +and (as in Greece and in part of Asia Minor) constitute an individual local +climate with respect to heat, moisture, transparancy of atmosphere, and +frequency of winds and storms. These circumstances have at all times +exercised a powerful influence on the character and cultivation of natural +products, and on the manners and institutions of neighboring nations, and +even on the feelings with which they regard one another. This character of +'geographical individuality' attains its maximum, if we may be allowed so to +speak, in countries where the differences in the configuration of the soil +are the greatest possible, either in a vertical or horizontal direction, +both in relief and in the articulation of the continent. The greatest +contrast to these varieties in the relations of the surface of the earth are +manifested in the Steppes of Northern Asia, the grassy plains (savannahs, +llanos, and pampas) of the New Continent, the heath ('Ericeta') of Europe, +and the sandy and stony deserts of Africa. + +The law of the decrease of heat with the increase of elevation at different +latitudes is one of the most important subjects involved in the study of +meteorological processes, of the geography of plants, of the theory of +terrestrial refraction, and of the various hypotheses that relate to the +determination of the height of the atmosphere. In the many mountain +journeys which I have undertaken, both within and without the tropics, the +investigation of this law has always formed a special object of my +researches.* + + +[footnote] *Humboldt, 'Recueil d'Observations Astronomiques', t. i., p. +126-140; 'Relation Historique', t. i., p. 119, 141, 227; Biot, in +'Connaissance des Temps pour l'an' 1841, p. 90-109. + + +Since we have acquired a more accurate knowledge of the true relations of +the distribution of heat on the surface of the earth, that is to say, of the +inflections of isothermal and isotheral lines, and their unequal distance +apart in the different eastern and western systems of temperature in Asia, +Central Europe, and North America, we can no longer ask the general +question, what fraction of the mean annual or summer temperature corresponds +to the difference of one degree of geographical latitude, taken in the same +meridian? In each system of 'isothermal' lines of equal curvature there +reigns a +p 328 +close and necessary connection between three elements, namely, the decrease +of heat in a vertical direction from below upward, the difference of +temperature for every one degree of geographical latitude, and the +uniformity in the mean temperature of a mountain station, and the latitude +of a point situated at the level of the sea. + +In the system of Eastern America, the mean annual temperature from the coast +of Labrador to Boston changes 1.6ºdegrees for every degree of latitude; +from Boston to Charleston about 1.7 degrees; from Charleston to the tropic +of Cancer, in Cuba, the variation is less rapid, being only 1.2 degrees. In +the tropics this diminution is so much greater, that from the Havana to +Cumana the variation is less than 0.4 degrees for every degree of latitude. + +The case is quite different in the isothermal system of Central Europe. +Between the parallels of 38 degrees and 71 degrees I found that the decrease +of temperature was very regularly 0.9degrees for every degree of latitude. +But as, on the other hand, in Central Europe the decrease of heat is 1.8 +degrees for about every 534 feet of vertical elevation, it follows that a +difference of elevation of about 267 feet corresponds to the difference of +one degree of latitude. The same mean annual temperature as that occurring +at the Convent of St. Bernard, at an elevation of 8173 feet, in lat. 45 +degrees 50' should therefore be met with at the level of the sea in lat. 75 +degrees 50'. + +In that part of the Cordilleras which falls within the tropics, the +observations I made at various heights, at an elevation of upward of 19,000 +feet, gave a decrease of 1 degree for every 341 feet; and my friend +Boussingault found, thirty years afterward, as a mean result, 319 feet. By +a comparison of places in the Cordilleras, lying at an equal elevation above +the level of the sea, either on the declivities of the mountains or even on +extensive elevated plateaux, I observed that in the latter there was an +increase in the annual temperature varying from 2.7 degrees to 4.1 degrees. +This difference would be still greater if it were not for the cooling effect +of nocturnal radiation. As the different climates are arranged in +successive strata, the one above the other, from the cacao woods of the +valleys to the region of perpetual snow, and as the temperature in the +tropics varies but little throughout the year, we may form to ourselves a +tolerably correct representation of the climatic relations to which the +inhabitants of the large cities in the Andes are subjected, by comparing +these climates with the temperatures of particular months in the plains of +France and Italy. While +p 329 +the heat which prevails daily on the woody shores of the Orinoco exceeds by +7.2 degrees that of the month of August at Palermo, we find, on ascending +the chain of the Andes, at Popayan, at an elevation of 3826 feet, the +temperature of the three summer months of Marseilles; at Quito, at an +elevation of 9541 feet, that of the close of May at Paris; and on the +Paramos, at a height of 11,510 feet, where only stunted Alpine shrubs grow, +though flowers still bloom in abundance, that of the beginning of April at +Paris. The intelligent observer, Peter Martyr de Aughiera, one of the +friends of Christopher Columbus, seems to have been the first who recognized +(in the expedition undertaken by Rodrigo Enrique Colmenares, in October, +1510) that the limit of perpetual snow continues to ascend as we approach +the equator. We read, in the fine work 'De Rebus Oceanicis',* "the River +Gaira comes from a mountain in the Sierra Nevada de Santa Maria, which, +according to the testimony of the companions of Colmenares, is higher than +any other mountain hitherto discovered. + + +[footnote] *Anglerius, 'De Rebus Oceanicis', Dec. xi., lib. ii., p. 140 +(ed. Col., 1574). In the Sierra de Santa Marta, the highest point of which +appears to exceed 19,000 feet (see my 'Relat. Hist.', t. ii., p. 214), there +is a peak that is still called Pico de Gaira. + + +It must undoubtedly be so if 'it retain snow perpetually' in a zone which is +not more than 10 degrees from the equinoctial line." The lower limit of +perpetual snow, in a given latitude, is the lowest line at which snow +continues during summer, or, in other words, it is the maximum of height to +which the snow-line recedes in the course of the year. But this elevation +must be distinguished from three other phenomena, namely, the annual +fluctuation of the snow-line, the occurrence of sporadic falls of snow, and +the existence of glaciers, which appear to be peculiar to the temperate and +cold zones. This last phenomenon, since Saussure's immortal work on the +Alps, has received much light, in recent times, from the labors of Venetz, +Charpentier, and the intrepid and persevering observer Agassiz. + +We know only the 'lower', and not the 'upper' limit of perpetual snow; for +the mountains of the earth do not attain to those ethereal regions of the +rarefied and dry strata of air, in which we may suppose, with Bouguer, that +the vesicles of aqueous vapor are converted into crystals of ice, and thus +rendered perceptible to our organs of sight. The lower limit of snow is +not, however, a mere function of geographical latitude or of mean annual +temperature; nor is it at the equator, or +p 330 +even, in the region of the tropics, that this limit attains its greatest +elevation above the level of the sea. The phenomenon of which we are +treating is extremely complicated, depending on the general relations of +temperature and humidity, and on the form of the mountains. On submitting +these relations to the test of special analysis, as we may be permitted to +do from the number of determinations that have recently been made,* we shall +find that the controlling causes are the differences in the temperature of +different seasons of the year; the direction of the prevailing winds and +their relations to this land and sea; the degree of dryness or humitidy in +the upper strata of the air; the absolute thickness of the accumulated +masses of fallen snow; the relation of the s-line to the total height of the +mountain; the relative position of the latter in the chain to which it +belongs, and the steepness of its declivity; the vicinity of either summits +likewise perpetually covered with show; the expansion, position, and +elevation of the plains from which the snow mountain rises as an isolated +peak or as a portion of a chain; whether this plain be part of the +sea-coast, or of the interior of a continent; whether it be covered with +wood or waving grass; and whether, finally, it consist of a dry and rocky +soil, or of a wet and marshy bottom. + + +[footnote] *See my table of the height of the line of perpetual snow, in +both hemispheres, from 71 degrees 15' north lat. to 53 degrees 54' south +lat., in my 'Asie Centrale', t. iii., p. 360. + + +The snow-line which, under the equator in South America, attains an +elevation equal to that of the summit of Mont Blanc in the Alps, and +descends, according to recent measurements, about 1023 feet lower toward the +northern tropic in the elevated plateaux of Mexico (in 19 degrees north +latitude), rises, according to Pentland, in the southern tropical zone (14 +degrees 30' to 18 degrees south latitude), being more than 2665 feet higher +in the maritime and western branch of the Cordilleras of Chili than under +the equator near Quito on Chimborazo, Cotopaxi, and Antisana. Dr. Gilles +even asserts that much further to the south, on the declivity of the volcano +of Peuquenes (latitude 33 degrees), he found the snow-line at an elevation +of between 14,520 and 15,030 feet. The evaporation of the snow in the +extremely dry air of the summer, and under a cloudless sky, is so powerful, +that the volcano of Aconcagua, northeast of Valparaiso (latitude 32 degrees +30'), which was found in the expedition of the Beagle to be more than 1400 +feet higher than Chimborazo, was on one occasion seen free from snow.• + + +[footnote] *Darwin, 'Journal of the Voyages of the Adventure and Beagle', +p. 297. As the volcano of Aconcagua was not at that time in a state of +eruption, we must not ascribe the remarkable phenomenon of this absence of +snow to the internal heat of the mountain (to the escape of heated air +through fissures), as is sometimes the case with Cotopaxi. Gilles, in the +'Journal of Natural Science', 1830, p. 316. + + +In +p 331 +an almost equal northern latitude (from 30 degrees 45' to 31 degrees), the +snow'line on the southern declivity of the Himalaya lies at an elevation of +12,982 feet, which is about the same as the height which we might have +assigned to it from a comparison with other mountain chains; on the northern +declivity, however, under the influence of the high lands of Thibet (whose +mean elevation appears to be about 11,510 feet), the snow-line is situated +at a height of 16,630 feet. This phenomenon, which has long been contested +both in Europe and in India, and whose causes I have attempted to develop in +various works, published since 1820,* possesses other grounds of interest +than +p 332 +those of a purely physical nature, since it exercises no inconsiderable +degree of influence on the mode of life of numerous tribes -- the +meteorological processes of the atmosphere being the controlling causes on +which depend the agricultural or pastoral pursuits of the inhabitants of +extensive tracts of continents. + + +[footnote] *See my 'Second Memoire sur les Montagnes de Inde', in the +'Annales de Chemie et de Physique', t. xiv., p. 5-55; and 'Asie Centrale', +t. iii., p. 281-327. While the most learned and experienced travelers in +India, Colebrooke, Webb, and Hodgson, Victor Jacquemont, Fobes Royle, Carl +von Hugel, and Vigne, who have all personally examined the Himalaya range, +are agreed, regarding the greater elevation of the snow-line on the +Thibeta=ian side, the accuracy of this statement is called in question by +John Gerard, by the geognoist MacClelland, the editor of the 'Calcutta +Journal', and by Captain Thomas Hutton, assistant surveyor of the Agra +Division. The appearance of my work on Central Asia gave rise to a +rediscussion of this question. A recent number (vol. iv., January, 1844) of +MacClelland and Griffith's 'Calcutta Journal of Natural History' contains, +however, a very remarkable and decisive notice of the determination of the +snow-line in the Himalaya. Mr. Batten, of the Bengal service, writes as +follows from Camp Semulka, on the Cosillah River, Kumaon: "In the July, +1843, No. 14 of your valuable Journal of Natural History, which I have only +lately had the opportunity of seeing, I read Captain Hutton's paper on the +snow of the Himalayas, and as I differed almost entirely from the +conclusions so confidently drawn by that gentleman, I thought it right, for +the interest of scientific truth, to prepare some kind of answer; as +however, on a more attentive perusal, I find that you yourself appear +implicitly to adopt Captain Hutton's views, and actually use these words, +'We have long been conscious of the error here so well ppointed out by +Captain Hutton, 'in common with every one who has visited the Himalayas,' I +feel more inclined to address you, in the first instance, and to ask whether +you will publish a short reply which I meditate; and whether your not to +Captain Hutton's paper was written after your own full and careful +examination of the subject, or merely on a general kind of acquiscence with +the fact and opinions of your able contributor, who is so well known and +esteemed as a collector of scientific data? Now I am one who have visited +the Himalaya on the western side; I have crossed the Borendo or Booria Pass +into the Buspa Valley, in Lower Kanawar, returning into the Rewaien +Mountains of Ghurwal by the Koopin Pass; I have visited the source of the +Jumna at Jumnootree; and, moving eastward, the sources of the Kalee or +Mundaknee branch of the Ganges at Kadarnath; of the Bishnoo Gunga, or +Aluknunda, at Buddrinath and Mana; of the Pindur at the foot of the Great +Peak Nundidavi; of the Dhoulee branch of the Ganges, beyond Neetee, crossing +and recrossing the pass of that name into Thibet; of the Goree or great +branch of the Sardah, or Kalee, near Oonta Dhoora, beyond Melum. I have +also, in my official capacity made the settlement of the Bhote Mehals of +this province. My residence of more than six years in the hills has thrown +me constantly in the way of European and native travelers, nor have I +neglected to acquire information from the recorded labors of others. Yet, +with all this experience, I am prepared to affirm that 'the perpetual +snow-line is at a higher elevation' on the northern slope of 'the Himalaya' +than on the southern slope. +"The facts mentioned by Captain Hutton appear to me only to refer to the +northern sides of all mountains in these regions, and not to affect, in any +way the reports of Captain Webb and others, on which Humboldt formed his +theory. Indeed how can any facts of one observer in one place falsify the +facts of another observer in another place? I willingly allow that the +north side of a hill retains the snow longer and deeper than the south side, +and this observation applies equally to heights in Bhote; but Humboldt's +theory is on the question of the perpetual snow-line, and Captain Hutton's +reference to Simla and Mussooree, and other mountain sites, are out of place +in this question, or else he fights against a shadow, or an objectioon of +his own creation. In no part of his paper does he quote accurately the +dictum which he wishes to oppose." +If the mean altitude of the thibetian highlands be 11,510 feet, they admit +of comparison with the lovely and fruitful plateau of Caxamarca in Peru. +But at this estimate they would still be 1300 feet lower than the plateau of +Bolivia at the Lake of Titicaca, and the causeway of the town of Potosi. +Ladak, as appears from Vigne's measurement, by determining the +boiling-point, is 9994 feet high. This is probably also the altitude of +H'Lassa (Yul-sung), a monastic city, which Chinese writers describe as the +'realm of pleasure', and which is surrounded by vineyards. Must not these +lie in deep valleys? + + +As the quantity of moisture in the atmosphere increases with the +temperature, this element, which is so important for the whole organic +creation, must vary with the hours of the day, the seasons of the year, and +the differences in latitude and elevation. Our knowledge of the hygrometric +relations of the Earth's surface has been very materially augmented of late +years by the general application of August's psychrometer, framed in +accordance with the views of Dalton and Daniell, for determining the +relative quantity of vapor, or the +p 333 +condition of moisture of the atmosphere, by means of the difference of the +'dew point' and of the temperature of the air. Temperature, atmospheric +pressure, and the direction of the wind, are all intimately connected with +the vivifying action of atmospheric moisture. This influence is not, +however, so much a consequence of the quantity of moisture held in solution +in different zones, as of the nature and frequency of the precipitation +which moistens the ground, whether in the form of dew, mist, rain, or snow. +According to the exposition made by Dove of the law of rotation, and to the +general views of this distinguished physicist,* it would appear that, in our +northern zone, "the elastic force of the vapor is greatest with a southwest, +and least with a northeast wind. On the western side of the windrose this +elasticity diminishes, while it increases on the eastern side; on the former +side, for instance, the cold, dense, and dry current of air repels the +warmer, lighter current containing an abundance of aqueous vapor, while on +the eastern side it is the former current which is repulsed by the latter. + + +[footnote] *See Dove, 'Meteorologische Vergleichung von Nordamerika und +Europa', in Schumacher's 'Jahrbuch fur' 1841, s. 311; and his +'Meteorologische Untersuchungen', s. 140. + + +The agreeable and fresh verdure which is observed in many trees in districts +within the tropics, where, for five or seven months of the yeqar, not a +cloud is seen on the vault of heaven, and where no perceptible dew or rain +falls, proves that the leaves are capable of extyracting water from the +atmosphere by a peculiar vital process of their own, which perhaps is not +alone that of producing cold by radiation. The absence of rain in the arid +plains of Cumana, Coro, and Ceara in North Brazil, forms a striking contrast +to the quanitity of rain which falls in some tropical regions, as, for +instance, in the Havana, where it would appear, from the average of six +years' observation by Ramong de la Sagra, the mean annual quantity of rain +is 109 inches, equal to four or five times that which falls at Paris or at +Geneva.* + + +[footnote] *The mean annual quantity of rain that fell in Paris between +1805 and 1822 was found by Arago to be 20 inches; in London, between 1812 +and 1827, it was determined by Howard at 25 inches; while at Geneva the mean +of thirty-two years' observation was 30.5 inches. In Hindostan, near the +coast, the quantity of rain is from 115 to 128 inches; and in the island of +Cuba, fully 142 inches fell in the year 1821. With regard to the +distribution of the quantity of rain in Central Europe, at different periods +of the year, see the admirable researches of Gasparin, Schuow, and Bravais, +in the 'Bibliotheque Universelle', t. xxxvviii., p. 54 and 264; 'Tableau du +Climat de l'Italie', p. 76; and Martins's notes to his excellent French +translation of Kämtz's 'Vorlesungen uber Meteorologie', p. 142. + + +On the declivity of the Cordilleras, +p 334 +the quantity of rain, as well as the temperature, diminishes with the +increase in the elevation.* + + +[footnote] *According to Boussingault ('Economie Rurale', t. ii., p. 693), +the mean quantity of rain that fell at Marmato (latitude 5 degrees 27', +altitude 4675 feet, and mean temperature 69 degrees) in the years 1833 and +1834 was 64 inches, while at Santa Fe de Bogota (latitude 4 degrees 36', +altitude 8685 feet, and mean temperature 58 degrees) it only amounted to 39 +1/2 inches. + + +My South American fellow-traveler, Caldas, found that, at Santa Fe de +Bogota, at an elevation of almost 8700 feet, it did not exceed 37 inches, +being consequently little more than on some parts of the western shore of +Europe. Boussingault occasionally observed at Quito that Saussure's +hygrometer receded to 26 degrees with a temperature of from 53.6 degrees to +55.4 degrees. Gay-Lussac saw the same hygrometer standing at 25.3 degrees +in his great aerostatic ascent in a stratum of air 7034 feet high, and with +a temperature of 39.2 degrees. The greatest dryness that has yet been +observed on the surface of the globe in the low lands is probably that which +Gustav Rose, Ehrenberg, and myself found in Northern Asia, between the +valleys of the Irtisch and the Oby. In the Steppe of Platowskaja, after +southwest winds had blown for a long time from the interior of the +Continent, with a temperature of 74.7 degrees, we found the dew point at 24 +degrees. The air contained only 16/100ths of aqueous vapor.* + + +[footnote] *For the particulars of this observation, see my 'Asie +Centrale', t. iii., p. 85-89 and 467; and regarding the amount of vapor in +the atmosphere in the lowlands of tropical South America, consult my 'Relat. +Hist.', t. i., p. 242-248; t. ii., p. 45, 164. + + +The accurate observers Kämtz, Bravais, and Martins have raised doubts +during the last few years regarding the greater dryness of the mountain air, +which appeared to be proved by the hygrometric measurements made by Saussure +and myself in the higher regions of the Alps and the Cordilleras. The +strata of air at Zurich and on the Faulhorn, which can not be considered as +an elevated mountain when compared with non-European elevations, furnished +the data employed in the comparisons made by these observers.* + + +[footnote] *Kämtz, 'Vorlesungen uber Meteorologie', s. 117. + + +In the tropical region of the Paramos (near the region where snow begins to +fall, at an elevation of between 12,000 and 14,000 feet), some species of +large flowering myrtle-leaved alpine shrubs are almost constantly bathed in +moisture; but this fqact does not actually prove the existence of any great +and absolute quantity of aqueous vapor at such an elevation, merely affording +p 335 +an evidence of the frequency of aqueous precipitation, in like manner as do +the frequent mists with which the lovely plateau of Bogota is covered. +Mists arise and disappear several times in the course of an hour in such +elevations as these, and with a calm state of the atmosphere. These rapid +alternations characterize the Paramos and the elevated plains of the chain +of the Andes. + +'The electricity of the atmosphere', whether considered in the lower or in +the upper strata of the clouds, in its silent problematical diurnal course, +or in the explosion of the lightning and thunder of the tempest, appears to +stand in a manifold relation to all phenomena of the distribution of heat, +of the pressure of the atmosphere and its disturbances, of hydrometeoric +exhibitions, and probably, also, of the magnetism of the external crust of +the earth. It exercises a powerful influence on the whole animal and +vegetable world; not merely by meteorological processes, as precipitations +of aqueous vapor, and of the acids and ammoniacal compounds to which it +gives rise, but also directly as an electric force acting on the nerves, and +promoting the circulation of the organic juices. This is not a place in +which to renew the discussion that has been started regarding the actual +source of atmospheric eletricity when the sky is clear, a phenomenon that +has alternately been ascribed to the evaporation of impure fluids +impregnated with earths and salts,* to the growth of plants,** or to some +other chemical decompositions on the surface of the earth, to the unequal +distribution of heat in the strata of the air,*** and, finally, according to +Peltier's intelligent researches,**** to the agency of a constant charge of +negative electricity in the terrestrial globe. + + +[footnote] *Regarding the conditions of electricity from evaporation at +high temperatures, see Peltier, in the 'Annales de Chimie', t. lxxv., p. 330. + +[footnote] **Pouillet, in the 'Annales de Chimie', t. xxxv., p. 405. + +[footnote] ***De la Rive, in his admirable 'Essai Historique sur +l'Electricite', p. 140. + +[footnote] ****Peltier, in the 'Comptes Rendus de l'Acad. des Sciences', t. +xii., p. 307; Becquerel, 'Traite de l'Electricite et du Magnetisme', t. iv., +p. 107. + + +Limiting itself to results yielded by electrometric observations, such, for +instance, as are furnished by the ingenious electro-magnetic apparatus first +proposed by Colladon, the physical description of the universe should merely +notice the incontestable increase of intensity in the general positive +electricity of the atmosphere,* accompanying an increase of altitude and and +the absence of trees, its daily variations (which, according to Clark's +experiments at Dublin, +p 336 +take place at more complicated periods than those found by Saussure and +myself), and its variations in the different seasons of the year, at +different distances from the equator, and in the different relations of +continental or oceanic surface. + + +[footnote] *Duprez, 'Sur l'Electricite de l'Air' (Bruxelles, 1844), p. +56-61. + + +The electric equilibrium is less frequently disturbed where the aerial ocean +rests on a liquid base than where it impends over the land; and it is very +striking to observe how, in extensive seas, small insular groups affect the +condition of the atmosphere, and occasion the formation of storms. In fogs, +and in the commencement of falls of snow, I have seen, in a long series of +observations, the previously permanent positive electricity rapidly pass +into the negative condition, both on the plains of the colder zones, and in +the Paramos of the Cordilleras, at elevations varying from 11,000 to 15,000 +feet. The alternate transition was precisly similar to that indicated by +the electrometer shortly before and during a storm.* + + +[footnote] *Humboldt, 'Relation Historique', t. iii., p. 318. I here only +refer to those of my experiiments in which the three-foot metallic conductor +of Saussure's electrometer was neither moved upward nor downward, nor, +according to Volta's proposal, armed with burning sponge. Those of my +readers who are well acquainted with the 'quaestiones vexatae' of +atmospheric electricity will understand the grounds for this limitation. +Respecting the formation of storms in the tropics, see my 'Rel. Hist.', t. +ii., p. 45 and 202-209. + + +When the vesicles of vapor have become condensed into clouds, having +definite outlines, the electric tension of the external surface will be +increased in proportion to the amount of electricity which passes over to it +from the separate vesicles of vapor.* + + +[footnote] *Gay-Lussac, in the 'Annales de Chimie et de Physique', t. +viii., p. 167. In consequence of the discordant views of Lame, Becquerel, +and Peltier, it is difficult to come to a conclusion regarding the cause of +the specific distribution of electricity in clouds, some of which have a +positive, and others a negative tension. The negative electricity of the +air, which near high water-falls is caused by a disintegration of the drops +of water -- a fact originally noticed by Tralles, and confirmed by myself in +various latitudes -- is very remarkable, and is sufficiently intense to +produce an appreciable effect on a delicate electrometer at a distance of +300 or 400 feet. + + +Slate-gray clouds are charged, according to Peltier's experiments at Paris, +with negative, and white, red, and orange-colored clouds with positive +electricity. Thunder clouds not only envelop the highest summits of the +chain of the Andes (I have myself seen the electric effect of lightning on +one of the rocky pinnacles which project upward of 15,000 feet above the +crater of the volcano of Toluca), but they have also been observed at a +vertical height of 26,650 feet over the low +p 337 +lands in the temperate zone.* + + + +[footnote] *Arago, in the 'Annuaire du Bureau des Longitudes pour' 1838, p. +246. + + +Sometimes, however, the stratum of cloud from which the thunder proceeds +sinks to a distance of 5000, or, indeed, only 3000 feet above the plain. + +According to Arago's investigations -- the most comprehensive that we +possess on this difficult branch of meteorology -- the evolution of light +(lightning) is of three kinds -- zigzag, and sharply defined at the edges; +in sheets of light, illuminating a whole cloud, which seems to open and +refeal the light within it; and in the form of fire-balls.* + + +[footnote] *Arago, op. cit., p. 249-266. (See also, p. 268-279.) + +The duration of the two first kinds scarcely continues the thousandth part +of a second; but the globular lightning moves much more slowly remaining +visible for several seconds. Occasionally (as is proved by the recent +observations, which have confirmed the description given by Nicholson and +Beccaria of this phenomenon), isolated clouds, standing high above the +horizon, continue uninterruptedly for some time to emit a luminous radiance +from their interior and from their margins, although there is no thunder to +be heard, and no indication of a storm; in some cases even hail-stones, +drops of rain, and flakes of snow have been seen to fall in a luminous +condition, when the phenomenon was not preceded by thunder. In the +geographical distribution of storms, the Peruvian coast, which is not +visited by thunder or lightning, presents the most striking contrast to the +rest of the tropical zone, in which, at certain seasons of the year, +thunder-storms occur almost daily, about four or five hours after the sun +has reached the meridian. According to the abundant evidence collected by +Arago* from the testiimony of navigators (Scoresby, Parry, Ross, and +Franklin), there can be no doubt that, in general, electric explosions are +extremely rare in high northern regions (between 70 degrees and 75 degrees +latitude). + + +[footnote] *Arago, op. cit., p. 388-391. The learned academician Von Baer, +who has done so much for the meteorology of Northern Asia, has not taken +into consideration the extreme rarity of storms in Iceland and Greenland; he +has only remarked ('Bulletin de l'Academie de St. Petersbourg', 1839, Mai) +that in Nova Zembla and Spitzbergen it is sometimes heard to thunder. + + +'The meteorological portion' of the descriptive history of nature which we +are now concluding shows that the processes of the absorption of light, the +liberation of heat, and the variations in the elastic and electric tension, +and in the hygrometric condition of the vast aerial ocean, are all so +intimately connected together, that each individual meteorological process +is modified by the action of all the others. The complicated +p 338 +nature of these disturbing causes (which involuntarily remind us of those +which the near and especially the smallest cosmical bodies, the satellites, +comets, and shooting stars, are subjected to in their course) increases the +difficulty of giving a full explanation of these involved meteorological +phenomena, and likewise limits, or wholly precludes, the possibility of that +predetermination of atmospheric changes which would be so important for +horticulture, agriculture, and navigation, no less than for the comfort and +enjoyment of life. Those who place the value of meteorology in this +problematic species of prediction rather than in the knowledge of the +phenomena themselves, are firmly convinced that this branch of science, on +account of which so many expeditions to distant mountainous regions have +been undertaken, has not made any very considerable progress for centuries +past. The confidence which they refuse to the physicist they yield to +changes of the moon, and to certain days marked in the calendar by the +superstition of a by-gone age. + +"Great local deviations from the distribution of the mean temperature are of +rare occurrence, the variations being in general uniformly distributed over +extensive tracts of land. the deviation, after attaining its maximum at a +certain point, gradually decreases to its limits; when these are passed, +however, decided deviations are observed in the 'opposite direction'. +Similar relations of weather extend more frequently from south to north than +from west to east. At the close of the year 1829 (when I had just completed +my Siberian journey), the maximum of cold was at Berlin, while North America +enjoyed an unusually high temperature. It is an entirely arbitrary +assumption to believe that a hot summer succeeds a severe winter, and that a +cool summer is preceded by a mild winter." Opposite relations of weather in +contiguous countries, or in two corn-growing continents, give rise to a +beneficient equalization in the prices of the products of the vine, and of +agricultural and horticultural cultivation. It has been justy remarked, +that it is the barometer alone which indicates to us the changes that occur +in the pressure of the air throughout all the aerial strata from the place +of observation to the extremest confines of the atmosphere, while* the +thermometer and psychrometer only acquaint us with all the variations +occurring in the local heat and moisture of the lower strata of +p 339 +air in contact with the ground. + + +[footnote] *Kämtz, in Schumacher's 'Jahrbuch fur' 1838, s. 285. Regarding +the opposite distribution of heat in the east and the west of Europe and +North America, see Dove, 'Repertorium der Physik', bd. iii., s. 392-395. + + +The simultaneous thermic and hygrometric modifications of the upper regions +of the air can only be learned (when direct observations on mountain +stations or aerostatic ascents are impracticable) from hypothetical +combinations, by making the barometer serve both as a thermometer and an +hygrometer. Important changes of weather are not owing to merely local +causes, situated at the place of observation, but are the consequence of a +disturbance in the equilibrium of the aerial currents at a great distance +from the surface of the Earth, in the higher strata of the atmosphere, +bringing cold or warm, dry or moist air, rendering the sky cloudy or serene, +and converting the accumulated masses of clouds into light feathery 'cirri'. + As, therefore, the inaccessibility of the phenomenon is added to the +manifold nature and complication of the disturbances, it has always appeared +to me that meteorology must first seek its foundation and progress in the +torrid zone, where the variations of the atmospheric pressure, the course of +hydro-meteors, and the phenomena of electric explosion, are all of periodic +occurrence. + +As we have now passed in review the whole sphere of inorganic terrestrial +life, and have briefly considered our planet with reference to its form, its +internal heat, its electro-magnetic tension, its phenomena of polar light, +the volcanic reaction of its interior on its variously composed solid crust, +and, lastly, the phenomena of its two-fold envelopes -- the aerial and +liquid ocean -- we might, in accordance with the older method of treating +physical geography, consider that we had completed our descriptive history +of the globe. But the nobler aim I have proposed to myself, of raising the +contemplation of nature to a more elevated point of view, would be defeated, +and this delineation of nature would appear to lose its most attractive +charm, if it did not also include the sphere of organic life in the many +stages of its typical development. The idea of vitality is so intimatey +associated with the idea of the existence of the active, ever-blending +natural forces which animate the terrestrial sphere, that the creation of +plants and animals is ascribed in the most ancient mythical representations +of many nations to these forces, while the condition of the surface of our +planet, before it was animated by vital forms, is regarded as coeval with +the epoch of a chaotic conflict of the struggling elements. But the +empirical domain of objective contemplation, and the delineation of our +planet in its present condition, do not include a consideration +p 340 +of the mysterious and insoluble problems of origin and existence. + +A cosmical history of the universe, resting upon facts as its basis, has, +from the nature and limitations of its sphere, necessarily no connection +with the obscure domain embraced by a 'history of organisms',* if we +understand the word 'history' in its broadest sense. + + +[footnote] *The 'history of plants', which Endlicher and Unger have +described in a most masterly manner ('Grundzuge der Botanik', 1843, s. +449-468), I myself separated from the 'geography of plants' half a century +ago. In the aphorisms appended to my 'Subterranean Flora', the following +passage occurs: "Geognosia naturam animantem et inanimam vel, ut vocabulo +minus apto, ex antiquitate saltem haud petito, utar, corpora vitur capita: +Geographia oryctologica quam simpliciter Geognosiam vel Geologiam dicunt, +virque acutissimus Wernerus egregie digessit; Geographia zoologica, cujus +doctrinae fundamenta Zimmermannus et Treviranus jecerunt; et Geographic +plantarum quam aequales nostri diu intactam reliquerunt. Geographia +plantarum vincula et cognationem tradit, quibus omnia vegetabilia inter se +connexa sint, terraetractur quos teneant, in aerem atmosphaericum quae sit +eorum vis ostendit, saxa atque rupes quibus potissimum algarum primordiis +radicibusque destruantur docet, et quo pacto in telluris superficie humus +nascatur, commemorat. Est itaque quod differat inter Geognosiam et +Physiographiam, 'historia naturalis' perperam nuncupatam quum Zoognosia, +Phytognosia, et Oryctognosia, quae quidem omnes in naturae investigatione +versantur, non nisi singulorum animalium, plantarum, rerum metallicarum vel +(venia sit verbo) fossilium formas, anatomen, vires scrutautur. Historia +Telluris, Geognosiae magis quam Physiographiae affinis, nemini adhuc tenata, +plantarum animaliumque genera orbem inhabitantia primaevum, migrationes +eorum compluriumque interitum, ortum quem montes, valles, saxorum strata et +vemae metalliferae ducunt, aerem, mutatis temporum vicibus, modo purum, modo +vitiatum, terrae superficiem humo plantisque paulatim obtectam, fluminum +inundantium impetu denuo nudatam, iterumque siccatam et gramine vestitam +commemorat. Igitur Historia zoolopgica, Historia plantarum et Historia +oryctologica, quae non nisi pristinum orbis terrae statum indicant, a +Geognosia probe distinguendae." -- Humboldt, 'Flora Friburgensis +Subterranea, cui accedunt Aphorismi ex Physiologia Chemica Plantarum', 1793, +p. ix.-x. Respecting the "spontaneous motion." which is referred to in a +subsequent part of the text, see the remarkable passage in Aristotle, 'De +Coelo,' ii., 2, p. 284, Bekker, where the distinction between animate and +inanimate bodies is made to depend on the internal or external position of +the seat of the determining motion. "No movement," says the Stagirite, +"proceeds from the vegetable spirit, because plants are buried in a still +sleep, from which nothing can arouse them" (Aristotle, 'De Generat. +Animal.', v. i., p. 778, Bekker); and again, "because plants have no desires +which incite them to spontaneous motion." (Arist., 'De Somno et Vigil'., +cap. i., p. 455, Bekker.) + + +It must, however, be remembered, that the inorganic crust of the Earth +contains within it the same elements that enter into the structure of animal +and vegetable organs. A physical cosmography would therefore be incomplete +p 341 +if it were to omit a consideration of these forces, and of the substances +which enter into solid and fluid combinations in organic tissues, under +conditiions which, from our ignorance of their actual nature, we designate +by the vague term of 'vital forces', and group into various systems in +accordance with more or less perfectly conceived analogies. The natural +tendency of the human mind involuntarily prompts us to follow the physical +phenomena of the Earth, through all their varied series, until we reach the +final stage of the morphological evolution of vegetable forms, and the +self-determining powers of motion in animal organisms. And it is by these +links that 'the geography of organic beings -- of plants and animals' -- is +connected with the delineation of the inorganic phenomena of our terrestrial +globe. + +Without entering on the difficult question of 'spontaneous motion', or, in +other words, on the difference between vegetable and animal life, we would +remark, that if nature had endowed us with microscopic powers of vision, and +the integuments of plants had been rendered perfectly transparent to our +eyes, the vegetable world would present a very different aspect from the +apparent immobility and repose in which it is now manifested to our senses. +The interior portion of the cellular structure of their organs is +incessantly animated by the most varied currents, either rotating, ascending +and descending, remifying, and ever changing their direction, as manifested +in the motion of the granular mucus of marine plants (Naiades, Characeae, +Hydrocharidae), and in the hairs of phanerogamic land plants; in the +molecular motion first discovered by the illustrious botanist Robert Brown, +and which may be traced in the ultimate portions of every molecule of +matter, even when separated from the organ; in the gyratory currents of the +globules of cambium ('cyclosis') circulating in their peculiar vessels; and, +finally, in the singularly articulated self-unrolling filamentous vessels in +the antheridia of the chara, and in the reproductive organs of liverworts +and algae, in the structural conditions of which Meyen, unhappily too early +lost to science, believed that he recognized an analogy with the spermatozoa +of the animal kingdom.* + + +[footnote] *["In certain parts, probably, of all plants, are found peculiar +spiral filaments, having a striking resemblance to the spermatozoa of +animals. They have been long known in the organs called the antheridia of +mosses, Hepaticcae, and Characeae, and have more recently been discovered in +peculiar cells on the germinal frond of ferns, and on the very young leaves +of the buds of Phanerogamia. They are found in peculiar cells, and when +these are placed in water they are torn by the filament, which commences an +active spiral motion. The signification of these organs is at present quite +unknown; they appear, from the researches of Nägeli, to resemble the cell +mucilage, or proto-plasma, in composition, and are developed from it. +Schleiden regards them as mere mucilaginous deposits, similar to those +connected with the circulation in cells, and he contends that the movement +of these bodies in water is analogous to the molecular motion of small +particles of organic and inorganic substances, and depends on mechanical +causes." -- 'Outlines of Structural and Physiological Botany', by A. +Henfrey, F.L.S., etc., 1846, p. 23.] -- Tr. + + +If to these +p 342 +manifold currents and gyratory movements we add the phenomena of endosmosis, +nutrition, and growth, we shall have some idea of those forces which are +ever active amid the apparent repose of vegetable life. + +Since I attempted in a former work, 'Ansichten der Natur' (Views of Nature), +to delineate the universal diffusion of life over the whole surface of the +Earth, in the distribution of organic forms, both with respect to elevation +and depth, our knowledge of this branch of science has been most remarkably +increased by Ehrenberg's brilliant discovery "on microscopic life in the +ocean, and in the ice of the polar regions" -- a discovery based, not on +deductive conclusions, but on direct observation. The sphere of vitality, +we might almost say, the horizon of life, has been expanded before our eyes. + "Not only in the polar regions is there an uninterrupted development of +active microscopic life, where larger animals can no longer exist, but we +find that the microscopic animals collected in the Antarctic expedition of +Captain James Ross exhibit a remarkable abundance of unknown and often most +beautiful forms. Even in the residuum obtained from the melted ice, +swimming about in round fragments in the latitude of 70 degrees 10', there +were found upward of fifty species of silicious-shelled Polygastria and +Coscinodiscae with their green ovaries, and therefore living and able to +resist the extreme severity of the cold. In the Gulf of Erebus, sixty-eight +silicious-shelled Polygastria and Phytolitharia, and only one +calcareous-shelled Polythalamia, were brought up by lead sunk to a depth of +from 1242 to 1620 feet." + +The greater number of the oceanic microscopic forms hitherto discovered have +been silicious-shelled, although the analysis of sea water does not yield +silica as the main constituent, and it can only be imagined to exist in it +in a state of suspension. It is not only at particular points in inland +seas, or in the vicinity of the land, that the ocean is densely inhabited by +living atoms, invisible to the naked eye, but samples of +p 343 +water taken up by Schayer on his return from Van Diemen's Land (south of the +Cape of Good Hope, in 57 degrees latitude, and under the tropics in the +Atlantic) show that the ocean in its ordinary condition, without any +apparent discoloration, contains numerous microscopic moving organisms, +which bear no resemblance to the swimming fragmentary silicious filaments of +the genus Chaetoceros, similar to the Oscillatoriae so common in our fresh +waters. Some few Polygastria, which have been found mixed with sand and +excrements of penguins in Cockburn Island, appear to be spread over the +whole earth, while others seem to be peculiar to the polar regions.* + + +[footnote] *See Ehrenberg's treatise 'Ueber das kleinste Leben im Ocean', +read before the Academy of Science at Berlin on the 9th of May, 1844. +[Dr. J. Hooker found Diatomaceae in countless numbers between the parallels +of 70 degrees and 80 degrees south, where they gave a color to the sea, and +also the icebergs floating in it. The death of these bodies in the South +Arctic Ocean is producing a submarine deposit, consisting entirely of the +silicious particles of which the skeletons of these vegetables are composed. + This deposit exists on the shores of Victoria Land and at the base of the +volcanic mountain Erebus. Dr. Hooker accounted for the fact that the +skeletons of Diatomaceae had been found in the lava of volcanic mountains, +by referring to these deposits at Mount Erebus, which lie in such a position +as to render it quite possible that the skeletons of these vegetables should +pass into the lower fissures of the mountain, and then passing into the +stream of lava, be thrown out, unacted upon by the heat to which they have +been exposed. See Dr. Hooker's Paper, read before the British Association +at Oxford, July, 1847.] -- Tr. + + +We thus find from the most recent observations that animal life predominates +amid the eternal night of the depths of ocean, while vegetable life, which +is so dependent on the periodic action of the solar rays, is most prevalent +on continents. The mass of vegetation on the Earth very far exceeds that of +animal organisms; for what is the volume of all the large living Cetacea and +Pachydermata when compared with the thickly-crosded colossal trunks of +trees, of from eight to twelve feet in diameter, which fill the vast forests +covering the tropical region of South America, between the Orinoco, the +Amazon, and the Rio de Madeira? And although the character of different +portions of the earth depends on the combination of external phenomena, as +the outlines of mountains -- the physiognomy of plants and animals -- the +azure of the sky -- the forms of the clouds -- and the transparency of the +atmosphere -- it must still be admitted that the vegetable mantle with which +the earth is decked constitutes the main feature of the picture. Animal +forms are inferior in mass, and their powers of motion often withdraw them +from our sight. The +p 344 +vegetable kingdom, on the contrary, acts upon our imagination by its +continued presence and by the magnitude of its forms; for the size of a tree +indicates its age, and here alone age is associated with the expression of a +constantly renewed vigor.* + + +[footnote] *Humboldt, 'Ansichten der Natur' (2te Ausgabe, 1826), bd. ii. s. +21. + + +In the animal kingdom (and this knowledge is also the result of Ehrenberg's +discoveries), the form which we term microscopic occupy the largest space, +in consequence of their rapid propagation.* + + +[footnote] *On multiplication by spontaneous division of the +mother-corpuscle and intercalation of new substance, see Ehrenberg 'Van den +jetzt lebenden Thierarten der Kreidebildung', in the 'Abhandl. der Berliner +Akad. der Wiss.', 1839, s. 94. The most powerful productive faculty in +nature is that manifested in the Vorticellae. Estimations of the greatest +possible development of masses will be found in Chrenberg's great work 'Die +Infusionsthierchen als volkommne Organismen', 1838, s. xiii., xix., and 244. + "The Milky Way of these organisms comprises the genera Monas, Vibrio, +Bacterium, and Bodo." The universality of life is so profusely distributed +throughout the whole of nature, that the smaller Infusoria live as parasites +on the larger, and are themselves inhabited by others, s. 194, 211, and 512. + + +The minutest of the Infusoria, the Monadidae, have a diameter which does not +exceed 1/3000th of a line, and yet these silicious-shelled organisms form in +humid districts subterranean strata of many fathoms in depth. + +The strong and beneficial influence exercised on the feelings of mankind by +the consideration of the diffusion of life, throughout the realms of nature +is common to every zone, but the impression thus produced is most powerful +in the equatorial regions, in the land of palms, bamboos, and arborescent +ferns, where the ground rises from the shore of seas rich in mollusca and +corals to the limits of perpetual snow. The local distribution of plants +embraces almost all heights and all depths. Organic forms not only descend +into the interior of the earth, where the industry of the miner has laid +open extensive excavations and sprung deep shafts, but I have also found +snow-white stalactiitic columns encircled by the delicate web of an Usnea, +in caves where meteoric water could alone penetrate through fissures. +Podurellae penetrate into the icy crevices of the glaciers on Mount Rosa, +the Grindelwald, and the Upper Aar; the Chionaea nivalis (formerly known as +Protococcus), exist in the polar snow as well as in that of our high +mountains. The redness assumed by the snow after lying on the ground for +soome time was known to Aristotle, and was probably observed by him on the +mountains of Macedonia.* + + +[footnote] *Aristot., 'Hist. Animal.', v. xix., p. 552, Bekk. + + +p 345 +While, on the loftiest summits of the Alps, only Lecideae, Parmeliae, and +Umbilicariae cast their colored but scanty covering over the rocks, exposed +by the melted snow, beautiful phanerogamic plants, as the Culcitium +rufescens, Sida pinchinchensis, and Saxifraga Boussingaulti, are still found +to flourish in the tropical region of the chain of the Andes, at an +elevation of more than 15,000 feet. Thermal springs contain small insects +(Hydroporus thermalis), Gallionellae, Oscillatoria and Confervae, while +their waters bathe the root-fibers of phanerogamic plants. As air and water +are aniimated at different temperatures by the presence of vital organisms, +so likewise is the interior of the different portions of animal bodies. +Animalcules have been found in the blood of the frog and the salmon; +according to Nordmann, the fluids in the eyes of fishes are often filled +with a worm that lives by suction (Diplostomum), while in the gills of the +bleak the same observer has discovered a remarkable double aniimalcule +(Diplozoon paradoxum), having a cross-shaped form with two heads and two +caudal extremities. + +Although the existence of meteoric Infusoria is more than doubtful, it can +not be denied that, in the same manner as the pollen of the flowers of the +pine is observed every year to fall from the atmosphere, minute infusorial +animalcules may likewise be retained for a time in the strata of the air, +after having been passively borne up by currents of aqueous vapor.* + + +[footnote] *Ehrenberg, op. cit., s. xiv., p. 122 and 403. The rapid +multiplication of microscopic organisms is, in the case of some (as, for +instance, in wheat-eels, wheel-animals, and water-bears or tardigrade +animalcules), accompanied by a remarkable tenacity of life. They have been +seen to come to life from a state of apparent death after being dried for +twenty-eight days in a vacuum with chloride of line and sulphuric acid, and +after being exposed to a heat of 248 degrees. See the beautiful experiments +of Doyere, in 'Mem. sur les Tardigrades et sur leur propriete de revenir a +la vie', 1842, p. 119, 129, 131, 133. Compare, also, Ehrenberg, s. 492-496, +on the revival of animalcules that had been dried during a space of many +years. + + +This circumstance merits serious attention in reconsidering the old +discussion respecting 'spontaneous generation',* and the +p 346 +more so, as Ehrenberg, as I have already remarked, has discovered that the +nebulous dust or sand which mariners often encounter in the vicinity of the +Cape Verd Islands, and even at a distance of 380 geographical miles from the +African shore, contains the remains of eighteen species of silicious-shelled +polygastric animalcules. + + +[footnote] *On the supposed "primitive transformation" of organized or +unorganized matter into plants and animals, see Ehrenberg, in Poggendorf's +'Annalen der Physik', bd. xxiv., s. 1-48, and also his 'Infusionsthierchen', +s. 121, 525, and Joh. Muller, 'Physiologie des Menschen' (4te Aufl., 1844), +bd. i., s. 8-17. It appears to me worthy of notice that one of the early +fathers of the Church, St. Augustine, in treating of the question how +islands may have been covered with new animals and plants after the flood, +shows himself in no way disinclined to adope the view of the so-called +"spontaneous generation" ('generatio aequivoca, spontanea aut primaria'). +"If," says he, "animals have not been brought to remote islands by angels, +or perhaps by inhabitants of continents addicted to the chase, they must +have been spontaneously produced upon the earth; although here the question +certainly arises, to what purpose, then, were animals of all kinds assembled +in the ark?" "Si e terra exort" sunt (bestiae) secundum originem primam, +quando dixit Deus" 'Producat terra animam vivam!' multo clarius apparet, +non tam reparandorum animalium causa, quam figurandarum variarum gentium (?) +propter ecclesiae sacramentumin arca fuisse omnia genera, si in insulis quo +transire non possent, multa animalia terra produxit." Augustinus, 'De +Civitate Dei', lib. xvi., cap. 7: 'Opera, ed. Monach. Ordinis S. +Benedicti', t. vii., Venet., 1732, p. 422. Two centuries before the tiime +of the Bishop of Hippo, we find, by extracts from Trogus Pompeius, that the +'generatio primaria' was brought forward in connection with the earliest +drying up of the ancient world, and of the high table-land of Asia, +precisely in the same manner as the terraces of Paradise, in the theory of +the great Linnaeus, and in the visionary hypotheses entertained in the +eighteenth century regarding the fabled Atlantis: "Quod si omnes quondam +terrae submersae profundo fuerunt, profecto editissilimam quamque partem +decurrentibus aquis primum detectam; humillimo autem solo eandem aquam +diutissime immoratam, et quanto prior quaeque pars terrarum siccata sit, +tanto prius animalia generare coepisse. Porro Scythiam adeo editiorem +omnibus terris esse ut cuncta flumina ibi nata in Maeotium, tum deinde in +Ponticum et Aegyptium mare decurrant." -- Justinus, lib. ii., cap. 1. The +erroneous supposition that the land of Scythia is an elevated table-land, is +so ancient that we meet with it most clearly expressed in Hippocrates, 'De +Aere et Aquis', cap. 6, 96, Coray. "Scythia," says he, "coonsists of high +and naked plains, which, without being crowned with mountains, ascend higher +and higher toward the north." + + +Vital organisms, whose relations in space are comprised under the head of +the geography of plants and animals, may be considered either according to +the difference and relative numbers of the types (their arrangement into +genera and species), or according to the number of individuals of each +species on a given area. In the mode of life of plants as in that of +animals, an important difference is noticed; they either exist in an +isolated state, or live in a social condition. Those species of plants +which I have termed 'social'* uniformly cover vast extents of land. + + +[footnote] *Humboldt, 'Aphorismi ex Physiologia Chemica Plantarum', in the +'Flora Fribergensis Subterranea', 1793, p. 178. + + +Among these we may reckon many of the marine Algae -- Cladoniae and mosses, +which extend over the desert steppes of Northern Asia -- grasses, and cacti +growing +p 347 +together like the pipes of an organ -- Avicennim and mangroves in the +tropics -- and forests of Coniferae and of birches in the plains of the +Baltic and in Siberia. This mode of geographical distribution determines, +together with the individual form of the vegetable world, the size and type +of leaves and flowers, in fact, the principal physiognomy of the district,* +its characteracter being but little, if at all, influenced by the +ever-moving forms of animal life, which, by their beauty and diversity, so +powerfully affect the feelings of man, whether by exciting the sensations of +admiration or horror. + + +[footnote] *On the physiognomy of plants, see Humboldt, 'Anischten der +Natur', bd. ii., s. 1-125. + + +Agricultural nations increase artificially the predominance of social +plants, and thus augment, in many parts of the temperate and northern zones, +the natural aspect of uniformity; and while their labors tend to the +extirpation of some wild plants, they likewise lead to the cultivation of +others, which follow the colonist in his most distant migration. The +luxuriant zone of the tropics offers the strongest resistance to these +changes in the natural distribution of vegetable forms. + +Observers who in short periods of time have passed over vast tracts of land, +and ascended lofty mountains, in which climates were ranged, as it were in +strata one above another, must have been early impressed by the regularity +with which vegetable forms are distributed. The results yielded by their +observations furnished the rough materials for a science, to which no name +had as yet been given. The same zones of regions of vegetation which, in +the sixteenth century, Cardinal Bembo, when a youth,*described on the +declivity of Aetna, were observed on Mount Ararat by Tournefort. + + +[footnote] *Aetna Dialogus.' 'Opuscula', Basil., 1556, p. 53, 54. A very +beautiful geography of the plants of Mount AEtna has recently been published +by Philippi. See 'Linnaea', 1832, s. 733. + + +He ingeniously compared the Alpine flora with the flora of plains situated +in different latitudes, and was the first to observe the influence exercised +in mountainous regions, on the distribution of plants by the elevation of +the ground above the level of the sea, and by the distance from the poles in +flat countries. Menzel, in an inedited work on the flora of Japan, +accidentally made use of the term 'geography of plants'; and the same +expression occurs in the fanciful but graceful work of Bernardin de St. +Pierre, 'Etudes de la Nature'. A scientific treatment of the subject began, +however, only when the geography of plants was intimately associated with +the study of the distribution +p 348 +of heat over the surface of the earth, and when the arrangement of vegetable +forms in natural families admitted of a numerical estimate being made of the +different forms which increase of decrease as we recede from the equator +toward the poles, and of the relations in which, in diffrent parts of the +earth, each family stood with reference to the whole mass of phanerogamic +indigenous plants of the same region. I consider it a happy circumstance +that, at the time during which I devoted my attention almost exclusively to +botanical pursuits, I was led by the aspect of the grand and strongly +characterized features of tropical scenery to direct my investigations +toward these subjects. + +The study of the geographical distribution of animals, regarding which +Buffon first advanced general, and, in most instances, very correct views, +has been considerably aided in its advance by the progress made in modern +times in the geography of plants. The curves of the isothermal lines, and +more especially those of the isochimenal lines, correspond with the limits +which are seldom passed by certain species of plants, and of animals which +do not wander far from their fixed habitation either with respect to +elevation or latitude.* + + +[footnote] *[The following valuable remarks by Professor Forbes, on the +correspondence existing between the distribution of existing faunas and +floras of the British Islands, and the geological changes that have affected +their area, will be read with much interest; they have been copied, by the +author's permission, from the 'Survey Report', p. 16: +"If the view I have put forward respecting the origin of the flora of the +British mountains be true -- and every geological and botanical probability, +so far as the are is concerned, favors it -- then must we endeavour to find +some more plausible cause than any yet shown for the presence of numerous +species of plants, and of some animals, on the higher parts of Alpine ranges +in Europe and Asia, specifically identical with animals and plants +indigenous in the regions very far north, and not found in the intermediate +lowlands. Tournefort first remarked and Humboldt, the great organizer of +the science of natural history geography, demonstrated, that zones of +elevation on mountains correspond to parallels of latitude, the higher with +the more northern or southern, as the case might be. It is well known that +this correspondence is recognized in the general 'facies' of the flora and +fauna, dependent on generic identities. But when announcing and +illustrating the law that climatal zones of animal and vegetable life are +mutually repeated or represented by elevation and latitude, naturalists have +not hitherto sufficiently (if at all) distinguished between the evidence of +that law, as exhibited by 'representative species' and by 'identical'. In +reality, the former essentially depend on the law, the latter being an +'accident' not necessarily dependent upon it, and which has hitherto not +been accounted for. In the case of the Alpine flora of Britain, the +evidence of the activity of the law, and the influence of the accident, are +inseparable, the law being maintained by a transported flora, for the +transmission of which I have shown we can not account by an appeal to +unquestionable geological events. In the case of the Alps and Carpathians, +and some other mountain ranges, we find the law maintained partly by a +representative flora, special in its region, i.e., by specific centers of +their own, and partly by an assemblage more or less limited in the several +ranges of identical species, these latter in several cases so numerous that +ordinary modes of transportation now in action can no more account for their +presence than they can for the presence of a Norwegian flora on the British +mountains. Now I am prepared to maintain that the same means which +introduced a sub-Arctic (now mmountain) flora into Britain, acting at the +same epoch, originated the identity, as far as it goes, of the Alpine floras +of middle Europe and Central Asia; for, now that we know the vast area swept +by the glacial sea, including almost the whole of Central and Northern +Europe, and belted by land, since greatly uplifted, which then presented to +the water's edge those climatal lconditions for which a sub-Arctic flora -- +destined to become Alpine -- was specially organized, the difficulty of +deriving such a flora from its paarent north, and of diffusing it over the +snowy hills bounding this glacial ocean, vanishes, and the presence of +identical species at such distant pooints remain no longer a mystery. +Moreover, when we consider that conditions during the epoch referred to, the +undoubted evidences of Continental observers, on the boounds of Asia by Sir +Roderick Murchison, in America by Mr. Lyell, Mr. Logan, Captain Bayfield, +and others, and that the botanical (and zoological as well) region, +essentially northern and Alpine, designated by Professor Schouw that 'of +saxifrages and mosses,' and first in his classification, exists now only on +the flanks of the great area which suffered such conditions; and that, +though similar conditions reappear, the relationship of Alpine and Arctic +vegetation in the southern hemisphere, with that in the northern, is +entirely maintained by 'representative', and not by identical species (the +general truth of my explanation of Alpine floras, including identical +species, becomes so strong, that the view proposed acquires fair claims to +be ranked as a theory, and not considered merely a convenient or bold +hypothesis."] -- Tr. + + +The +p 349 +elk, for instance, lives in the Scandinavian peninsula, almost ten degrees +further north than in the interior of Siberia, where the line of equal +winter temperature is so remarkably concave. Plants migrate in the germ; +and, in the case of many species, the seeds are furnished with organs +adapting them to be conveyed to a distace through the air. When once they +have taken root, they become dependent on the soil and on the strata of air +surrounding them. Animals, on the contrary, can at pleasure migrate from +the equator toward the poles; and this they can more especially doo where +the isothermal lines are much inflected, and where hot summers succeed a +great degree of winter cold. The royal tiger, which in no respect differs +from the Bengal species, penetrates every summer into +p 350 +the north of Asia as far as the latitudes of Berlin and Hamburg, a fact of +which Ehrenberg and myself have spoken in other works.* + + +[footnote] *Ehrenberg, in the 'Annales des Sciences Naturelles', t. xxi., +p. 387, 412; Humboldt, 'Asie Centrale', t. i., p. 339-342, and t. iii., p. +96-101. + + +The grouping or association of diffrent vegetable species, to which we are +accustomed to apply the term 'Floras', do not appear to me, from what I have +observed in different portions of the earth's surface, to manifest such a +predominance of individual families as to justify us in marking the +geographical distinctions between the regions of the Umbellatae, of the +Solidaginae, of the Labiatae, or the Scitamineae. With reference to this +subject, my views differ from those of several of my friends, who rank among +the most distinguished of the botanists of Germany. The character of the +floras of the elevated plateaux of Mexico, New Granada, and Quito, of +European Russia, and of Northern Asia, consists, in my opinion, not so much +in the relatively larger number of the species presented by one or two +natural families, as in the more complicated relations of the coexistence of +many families, and in the relative numerical value of their species. The +Gramineae and the Cyperaceae undoubtedly predominate in meadow lands and +stppes, as do Coniferae, Cupuliferae, and Betulineae in our northern woods; +but this predominance of certain forms is only apparent, and owing to the +aspect imparted by the social plants. The north of Europe, and that portion +of Siberia which is situated to the north of the Altai Mountains, have no +greater right to the appellation of a region of Gramineae and Coniferae than +have the boundless llanos between the Orinoco and the mountain chain of +Caraccas, or the pine forests of Mexico. It is the coexistence of forms +which may partially replace each other, and their relative numbers and +association, which give rise either to the general impression of luxuriance +and diversity, or of poverty and uniformity in the contemplation of the +vegetable world. + +In this fragmentary sketch of the phenomena of organization, I have ascended +from the simplest cellI -- the first manifestation of life -- progressively +to higher structures. "The +p 351 +association of mucous granules constitutes a definitely-formed cytoblase, +around which a vesicular membrane forms ia closed well," this cell being +either produced from another pre-existing cell,** or being due to a cellular +formation, which, as in the case of the fermentation-fungus, is concealed in +the obscurity of some unknown chemical process.*** + + +[footnote] *Schleiden, 'Ueber die Entwicklungsweise der Pflanzenzellen', in +Muller's 'Archiv fur Anatomie und Physiologie', 1838, s. 137-176; also his +'Grundzuge der wissenschaftlichen Botanik', th. i., s. 191, and th. ii., s +11. Schwann, 'Mikroscopische Untersucungen uber die Uebereinstimmung in der +Struktur und dem Wachsthum der Thiere und Pflanzen', 1839, s. 45, 220. +Compare also, on similar propagation, Joh. Muller 'Physiologie des +Menschen', 1840, th. ii., s. 614. + + +[footnote] **Schleiden, 'Grundzuge der wissenschaftlichen Botanik', 1842, +th. i., s. 192-197. + + +[footnote] ***[On cellular formation, see Henfrey's 'Outlines of Structural +and Physiological Botany', op. cit., p. 16-22.] -- Tr. + + +But in a work like the present we can venture on no more than an allusion to +the mysteries that involve the question of modes of origin; the geography of +animal and vegetable organisms must limit itself to the consideration of +germs already developed, of their haabitation and transplantation, either by +voluntary or involuntary migrations, their numerical relation, and their +distribution over the surface of the earth. + +The general picture of nature which I have endeavored to delineate would be +incomplete if I did not venture to trace a few of the most marked features +of the human race, considered with reference to physical gradations -- to +the geographical distribution of contemporaneous types -- to the influence +exercised upon man by the forces of nature, and the reciprocal, although +weaker action which he in his turn exercises on these natural forces. +Dependent, although in a lesser degree than plants and animals, on the soil, +and on the meteorological processes of the atmosphere with which he is +surroounded -- escaping more readily from the control of natural forces, by +activity of mind and the advance of intellectual cultivation, no less than +by his wonderful capacity of adapting himself to all climates -- man every +where becomes most essentially associated with terrestrial life. It is by +these relations that the obscure and much-contested problem of the +possibility of one common descent enters into the sphere embraced by a +general physical cosmography. The investigation of this problem will impart +a nobler, and, if I may so express myself, more purely human interest to the +closing pages of this section of my work. + +The vast domain of language, in whose varied structure we see mysteriously +reflected the destinies of nations, is most intimately associated with the +affinity of races; and what even slight differences of races may effect is +strikingly manifested in the history of the Hellenic nations in the zenith +of their intellectual cultivation. The most important questions of the +civilization of mankind are connected with the ideas of races, +p 352 +community of language, and adherence to one original direction of the +intellectual and moral faculties. + +As long as attention was directed solely to the extremes in varieties of +color and of form, and to the vividness of the first impression of the +senses, the observer was naturally disposed to regard races rather as +originally different species than as mere varieties. The permanence of +certain types* in the midst of the most hostile influences, especially of +climate, appeared to favor such a view, notwithstanding the shortness of the +interval of time from which the historical evidence was derived. + + +[footnote] *Tacitus, in his speculations on the inhabitants of Britain +('Agricola', cap. ii.), distinguishes with much judgment between that which +may be owing to the local climatic relations, and that which, in the +immigrating races, may be owing to the unchangeable influence of a +hereditary and transmitted type. "Britanniam qui mortales initio coluerunt, + indigenae an advecti, ut inter barbaros, parum coompertum. Habitus +corporis varii, alque ex eo argumenta; namque rutilae Caledoniam habitantium +comae, magni artus Germanicam originem adseverant. Silu ram colorati vultus +et torti plerumque crines, et posita contra Hispania, Iberos veteres +trajecisse, easque cedes occupasse fidem faciunt: proximi Gallis, et +similes sunt: seu durante originis vi; seu procurrentibus in diversa +terris, positio coeli corporibus habitum dedit." Regarding the persistency +of types of conformation in the hot and cold regions of the earth, and in +the mountainous districts of the New Continent, see my 'Relation +Historique', t. i., p. 498, 503, and t. ii., p. 572, 574. + + +In my opinion, however, more powerful reasons can be advanced in support of +the theory of the unity of the human race, as, for instance, in the many +intermediate gradations* in the color of the skin and in the form of the +skull, which have been made known to us in recent times by the rapid +progress of geographical knowledge -- the analogies presented by the +varieties in the species of many wild and domesticated animals -- and the +more correct observations collected regarding the limits of fecundity in +hybrids.** + + +[footnote] On the American races generally, see the magnificent work of +Samuel George Morton, entitled 'Crania Americana', 1839, p. 62, 86; and on +the skulls brought by Pentland from the highlands ot titicaca, see the +'Dublin Journal of Medical and Chemical Science', vol. v., 1834, p. 475; +also Alcide d'Orbigny, 'L'homme Americain considere sous ses rapports +Physiol. et Mor.', 1839, p. 221; and the work by Prince Maximilian of Wied, +which is well worthy of notice for the admirable ethnographical remarks in +which it abounds, entitled 'Reise in das Innere von Nordamerika' (1839). + + +[footnote] ** Rudolph Wagner, 'Ueber Blendlinge und Bastarderzeugung', in +his notes to the German translation of Prichard's 'Physical History of +Mankind', vol. i., p. 138-150. + + +The greater number of the contrasts which were formerly supposed to exist, +have disappeared before the laborious researches of Tiedemann on the brain +of negroes and of Europeans, and the anatomical investigations +p 353 +of Vrolik and Weber on the form of the pelvis. On comparing the +dark-colored African nations, on whose physical history the admirable work +of Prichard has thrown so much light, with the races inhabiting the islands +of the South-Indian and West-Australian archipelago, and with the Papuas and +Alfourous (Haroforas, Endamenes), we see that a black skin, woolly hair, and +a negro-like cast of countenance are not necessarily connected together.* + + +[footnote] *Prichard, op. cit., vol. ii., p. 324. + + +So long as only a small portion of the earth was known to the Western +nations, partial views necessarily predominated, and tropical heat and a +black skin consequently appeared inseparable. "The Ethiopians," said the +ancient tragic poet Theodectes of Phaselis,* "are colored by the near +sun-god in his course with a sooty luster, and their hair is dried and +crisped with the heat of his rays." + + +[footnote] *Onesicritus, in Strabo, xv., p. 690, 695, Casaub. Welcker, +'Griechische Tragodien', abth. iii., s. 1078, conjectures that the verses of +Theodectes, cited by Strabo, are taken from a list tragedy, which probably +bore the title of "Memnon." + + +The campaigns of Alexander, which gave rise to so many new ideas regarding +physical geography, likewise first excited a discussion on the problematical +influence of climate on races. "Families of animals and plants," writes one +of the greatest anatomists of the day, Johannes Muller, in his noble and +comprehensive work, 'Physiologie des Menschen', "undergo, within certain +limitations peculiar to the different races and species, various +modifications in their distribution over the surface of the earth, +propagating these variations as organic types of species.* + + +[footnote] *[In illustration of this, the conclusions of Professor Edward +Forbes respecting the origin and diffusion of the British flora may be +cited. See the 'Survey Memoir' already quoted, 'On the Connection between +the Distribution of the existing Fauna and Flora of the British Islands, +etc.', p. 64. "1. The flora and fauna, terrestrial and marine, of the +British islands and seas, have originated, so far as that area is concerned, +since the melocene epoch. 2. The assemblages of animals and plants +compositing that fauna and flora did not appear in the area they now inhabit +simultaneously, but at several distinct points in time. 3. Both the fauna +and flora of the British islands and seas are composed partly of species +which, either permanently or for a time, appeared in that area before the +glacial epoch; partly of such as inhabited it during that epoch; and in +great part of those which did not appear there until afterward, and whose +appearance on the earth was coeval with the elevation of the bed of the +glacial sea and the consequent climatal changes. 4. The greater part of +the terrestrial animals and flowering plants now inhabiting the British +islands are members of specific centers beyond their area, and have migrated +to it over continuous land before, during, or after the glacial epoch. 5. +The climatal conditions of the area under discussion, and north, east, and +west of it, were severer during the glacial epoch, when a great part of the +space now occupied by the British isles was under water, than they are now +or were before; but there is good reason to believe that, so far from those +conditions having continued severe, or having gradually diminished in +severity southward of Britain, the cold region of the glacial epoch came +directly into contact with a region of more southern and thermal character +than that in which the most southern beds of glacial drift are now to be met +with. 6. This state of things did not materially differ from that now +existing, under corresponding latitudes, in the North American, Atlantic, +and Arctic seas, and on their bounding shores. 7. The Alpine floras of +Europe and Asia, so far as they are identical with the flora of the Arctic +and sub-Arctic zones of the Old World, are fragments of a flora which was +diffused from the north, either by means of transport not now in action on +the temperate coasts of Europe, or over continuous land which no longer +exists. The deep sea fauna is in like manner a fragment of the general +glacial fauna. 8. The floras of the islands of the Atlantic region, +between the Gulf-weed Bank and the Old World, are fragments of the Great +Mediterranean flora, anciently diffused over a land consistuted out of the +upheaval and never again subjerged bed of the (shallow) Meiocene Sea. This +great flora, in the epoch anterior to, and probably, in part, during the +glacial period, had a greater extension northward than it now presents. 9. +The termination of the glacial epoch in Europe was marked by a recession of +an Arctic fauna and flora northward, and of a fauna and flora of the +Mediterranean type southward; and in the interspace thus produced there +appeared on land the Germanic fauna and flora, and in the sea that fauna +termed Celtic. 10. The causes which thus preceded the appearance of a new +assemblage of organized beings were the destruction of many species of +animals, and probably also of plants, either forms of extremely local +distribution, or such as were not capable of enduring many changes of +conditions -- species, in short, with very limited capacity for horizontal +or vertical diffusion. 11. All the changes before, during, and after the +glacial epoch appear to have been gradual, and not sudden, so that no marked +line of demarkation can be drawn between the creatures inhabiting the same +element and the same locality during two proximate periods."] -- Tr. + + +The different races of mankind are forms of one sole species, by the union +of two of whose members descendants are propagated. They are not different +species of a genus, since in that case their hybrid descendants would remain +unfruitful. But whether the human races have descended from several +primitive races of men, or from one alone, is a question that can not be +determined from experience."* + + +[footnote] *Joh. Muller, 'Physiologie des Menschen', bd. ii., s. 768. + + +Geographical investigations regarding the ancient 'seat', the so-called +'cradle of the human race', are not devoid of a mythical +p 355 +character. "We do not know," says Wilhelm von Humboldt, in an unpublished +work 'On the Varieties of Languages and Nations', "either from history or +from authentic tradition, any period of time in which the human race has not +been divided into social groups. Whether the gregarious condition was +original, or of subsequent occurrence, we have no historic evidence to show. + The separate mythical relations found to exist independently of one another +in different parts of the earth, appear to refute the first hypothesis, and +concur in ascribing the generation of the whole human race to the union of +one pair. The general prevalence of this myth has cause it to be regarded +as a traditionary record transmitted from the primitive man to his +descendants. But this very circumstance seems rather to prove that it has +no historical foundation, but has simply arisen from an identity in the mode +of intellectual conception, which has every where led man to adopt the same +conclusion regarding identical phenomena; in the same manner as many myths +have doubtlessly arisen, not from any historical connection existing between +them, but rather from an identity in human thought and imagination. Another +evidence in favor of the purely mythical nature of this belief is afforded +by the fact that the first origin of mankind -- a phenomenon which is wholly +beyond the sphere of experience -- is explained in perfect conformity with +existing views, being considered on the principle of the colonization of +some desert island or remote mountainous valley at a period when mankind had +already existed for thousands of years. It is in vain that we direct our +thoughts to the solution of the great problem of the first origin, since man +is too intimately associated with his own race and with the relations of +time to conceive of the existence of an individual independently of a +preceding generation and age. A solution of those difficult questions, +which can not be determined by inductive reasoning or by experience -- +whether the belief in this presumed traditional condition be actually based +on historical evidence, or whether mankind inhabited the earth in gregarious +associations from the origin of the race -- can not, therefore, be +determined from philological data, and yet its elucidation ought not to be +sought from other sources." + +The distribution of mankind is therefore only a distribution into +'varieties', which are commonly designated by the somewhat indefinite term +'races'. As in the vegetable kingdom, and in the natural history of birds +and fishes, a classification into many small families is based on a surer +foundation than +p 356 +where large sections are separated into a few but large divisions; so it +also appears to me, that in the determination of races a preference should +be given to the establishment of small families of nations. Whether we +adopt the old classification of my master, Blumenbach, and admit 'five' +races (the Caucasian, Mongolian, American, Ethiopian, and Malayan), or that +of Prichard, into 'seven races'* (the Iranian, Turanian, American, +Hottentots and Bushmen, Negroes, Papuas, and Alfourons), we fail to +recognize any typical sharpness of definition, or any general or +well-established principle in the division of these groups. + + +[footnote] *Prichard, op. cit., vol. i., p. 247. + + +The extremes of form and color are certainly separated, but without regard +to the races, which can not be included in any of these classes, and which +have been alternately termed Scythian and Allophyllic. Iranian is certainly +a less objectionable term for the European nations than Caucasian; but it +may be maintained generally that geographical denominations are very vague +when used to express the points of departure of races, more especially where +the country which has given its name to the race, as, for instance, Turan +(Mawerannahr), has been inhabited at different periods* by Indo-Germanic and +Finnish, and not by Mongolian tribes. + + +[footnote] *The late arrival of the Turkish and Mongolian tribes on the +Oxus and on the Kirghis Steppes is opposed to the hypothesis of Niebuhr, +according to which the Scythians of Herodotus and Hippocrates were +Mongolians. It seems far more probable that the Scythians (Scoloti) should +be referred to the Indo-Germanic Massagetae (Alani). The Mongolian, true +Tartars (the latter term was afterward falsely given to purely Turkish +tribes in Russia and Siberia), were settled, at that period, far in the +eastern part of Asia. See my 'Asie Centrale', t. i., p. 239, 400; 'Examen +Critique de l'Histoire de la Geogr.', th. ii., p. 320. A distinguished +philologist, Professor Buschmann, calls attention to the circumstance that +the poet Firdousi, in his half-mythical prefatory remarks in the +'Schahnameh', mentions "a fortress of the Alani" on the sea-shore, in which +Selm took refuge, this prince being the eldest son of the King Feridun, who +in all probability lived two hundred years before Cyrus. The Kirghis of the +Scythian steppe were originally a Finnish tribe; their three hordes probably +constitute in the present day the most numerous nomadic nation, and their +tribe dwelt, in the sixteenth century, in the same steppe in which I have +myself seen them. The Byzantine Menander (p. 380-382, ed. Nieb.) expressly +states that the Chacan of the Turks (Thu-Khiu), in 569, made a present of a +Kirghis slave to Zemarchus, the embassador of ustinish II.; he terms her a +[Greek word]; and we find in Abulgasi ('Historia Mongolorum et Tatarorum') +that the Kirghis are called Kirkiz. Similarity of manners, where the nature +of the country determines the principal characteristics, is a very uncertain +evidence of identity of race. The life of the steppes produces among the +Turks (Ti Tukiu), the Baschkirs (Fins), the Kirghis, the Torgodi and +Dsungari (Mongolians), the same habits of nomadic life, and the same use of +felt tents, carried on wagons and pitched among herds of cattle. + + +p 357 +Languages, as intellectual creations of man, and as closely interwoven with +the development of mind, are, independently of the 'national' form which +they exhibit, of the greatest importance in the recognition of similarities +or differences in races. This importance is especially owing to the clew +which a community of descent affords in treading that mysterious labyrinth +in which the connection of physical powers and intellectual forces manifests +itself in a thousand different forms. The brilliant progress made within +the last half century, in Germany, in philosophical philology, has greatly +facilitated our investigations into the 'national' character* of languages +and the influence exercised by descent. + + +[footnote] *Wilhelm von Humboldt, 'Ueber die Verschiedenheit der +menschlichen Sprachbaues', in his great work 'Ueber die Kawi-Sprache auf der +Insel Java', bd. i., s. xxi., xlviii., and ccxiv. + + +But here, as in all domains of ideal speculation, the dangers of deception +are closely linked to the rich and certain profit to be derived. + +Positive ethnographical studies, based on a thorough knowledge of history, +teach us that much caution should be applied in entering into these +comparisons of nations, and of the languages employed by them at certain +epochs. Subjection, long association, the influence of a foreign religion, +the blending of races, even when only including a small number of the more +influential and cultivated of the immigrating tribes, have produced, in both +continents, similarly recurring phenomena; as, for instance, in introducing +totally different families of languages among one and the same race, and +idioms, having one common root, among nations of the most different origin. +Great Asiatic conquerors have exercised the most powerful influence on +phenomena of this kind. + +But language is a part and parcel of the history of the development of mind; +and however happily the human intellect, under the most dissimilar physical +conditions, may unfettered pursue a self-chosen track, and strive to free +itself from the dominion of terrestrial influences, this emancipation is +never perfect. There ever remains, in the natural capacities of the mind, a +trace of something that has been derived from the influences of race or of +climate, whether they be associated with a land gladdened by cloudless azure +skies, or with the vapory atmosphere of an insular region. As, therefore, +richness and grace of language are unfolded from the most luxuriant +p 358 +depths of thought, we have been unwilling wholly to disregard the bond which +so closely links together the physical world with the sphere of intellect +and of the feelings by depriving this general picture of nature of those +brighter lights and tints which may be borrowed from considerations, however +slightly indicated, of the relations existing between races and languages. + +While we maintain the unity of the human species, we at the same time repel +the depressing assumption of superior and inferior races of men.* + + +[footnote] *The very cheerless, and, in recent times, too often discussed +doctrine of the unequal rights of men to freedom, and of slavery as an +institution in conformity with nature, is unhappily found most +systematically developed in Aristotle's 'Politica', i., 3, 5, 6. + + +There are nations more susceptible of cultivation, more highly civilized, +more enobled by mental cultivation than others, but none in themselves +nobler than others. All are in like degree designed for freedom; a freedom +which, in the ruder conditions of society, belongs only to the individual, +but which, in social states enjoying political institutions, appertains as a +right to the whole body of the community. "If we would indicate an idea +which, throughout the whole course of history, has ever more and more widely +extended its empire, or which, more than any other, testifies to the +much-contested and still more decidedly misunderstood perfectibility of the +whole human race, it is that of establishing our common humanity -- of +striving to remove the barriers which prejudice and limited views of every +kind have erected among men, and to treat all mankind, without reference to +religion, nation, or color, as one fraternity, one great community, fitted +for the attainment of one object, the unrestrained development of the +physical powers. This is the ultimate and highest aim of society, identical +with the direction implanted by nature in the mind of man toward the +indefinite extension of his existence. He regards the earth in all its +limits, and the heavens as far as his eye can scan their bright and starry +depths, as inwardly his own, given to him as the objects of his +contemplation, and as a field for the development of his energies. Even the +child longs to pass the hills or the seas which inclose his narrow home; +yet, when his eager steps have borne him beyond those limits, he pines, like +the plant, for his native soil; and it is by this touching and beautiful +attribute of man -- this longing for that which is unknown, and this fond +remembrance of that which is lost -- that he is spared from an exclusive +attachment to the present. +p 359 +Thus deeply rooted in the innermost nature of man, and even enjoined upon +him by his highest tendencies, the recognition of the bond of humanity +becomes one of the noblest leading principles in the history of mankind."* + + +[footnote] *Wilhelm von Humboldt, 'Ueber die Kawi-Sprache', bd. iii., s. +426. I subjoin the following extract from this work: "The impetuous +conquests of Alexander, the more politic and premeditated extension of +territory made by the Romans, the wild and cruel incursions of the Mexicans, +and the despotic acquisitions of the incas, have in both hemispheres +contributed to put an end to the separate existence of many tribes as +independent nations, and tended at the same time to establish more extended +international amalgamation. Men of great and strong minds, as well as whole +nations, acted under the influence of one idea, the purity of which was, +however, utterly unknown to them. It was Christianity which first +promulgated the truth of its exalted charity, although the seed sown yielded +but a slow and scanty harvest. Before the religion of Christ manifested its +form, its existence was only revealed by a faint foreshadowing presentiment. + In recent times, the idea of civilization has acquired additional +intensity, and has given rise to a desire of extending more widely the +relations of national intercourse and of intellectual cultivation; even +selfishness begins to learn that by such a course its interests will be +better served than by violent and forced isolation. Language more than any +other attribute of mankind, binds together the whole human race. By its +idiomatic properties it certainly seems to separate nations, but the +reciprocal understanding of foreign languages connects men together on the +other hand without injuring individual national characteristics." + + +With these words, which draw their charm from the depths of feeling, let a +brother be permitted to close this general description of the natural +phenomena of the universe. From the remotest nebulae and from the revolving +double stars, we have descended to the minutest organisms of animal +creation, whether manifested in the depths of ocean or on the surface of our +globe, and to the delicate vegetable germs which clothe the naked declivity +of the ice-crowned mountain summit; and here we have been able to arrange +these phenomena according to partially known laws; but other laws of a more +mysterious nature rule the higher spheres of the organic world, in which is +comprised the human species in all its varied conformation, its creative +intellectual power, and the languages to which it has given existence. A +physical delineation of nature terminates at the point where the sphere of +intellect begins, and a new world of mind is opened to our view. It marks +the limit, but does not pass it. + +p 360 is blank + +p 361 + +ADDITIONAL NOTES + +TO THE PRESENT EDITION. MARCH, 1849. + +__________ + +GIGANTIC BIRDS OF NEW ZEALAND. -- Vol. i., p. 287. +An extensive and highly interesting collection of bones, referrible to +several species of the 'Moa' (Dinornis of Owen), and to three or four other +genera of birds, formed by Mr. Walter Mantell, of Wellington, New Zealand, +has recently arrived in England, and is now deposited in the British Museum. + This series consists of between 700 and 800 speciments, belonging to +different parts of the skeletons of many individuals of various sizes and +ages. Some of the largest vertebrae, tibiae, and femora equal in magnitude +the most gigantic previously known, while others are not larger than the +corresponding bones of the living apteryx. Among these relics are the +'skulls' and 'mandibles' of two genera, the 'Dinornis' and 'Palapteryx'; +and of an extinct genus, 'Notornis', allied to the 'Rallidae'; and the +mandibles of a species of 'Nestor', a genus of nocturnal owl-like parrots, +of which only two living species are known.* + + +[footnote] *See Professor Owen's Memoir on these fossil remains, in +'Zoological Transactions', 1848. + + +These osseous remains are in a very different state of preservation from any +previously received from New Zealand; they are light and porous, and of a +light fawn-color; the most delicate processes are entire, and the +articulating surfaces smooth and uninjured; 'fragments of egg-shells', and +even the bony rings of the trachea and air tubes, are preserved'. + +The bones were dug up by Mr. Walter Mantell from a bed of marly sand, +containing magnetic iron, crystals of hornblende and augite, and the +detritus of augitic rocks and earthy volcanic tuff. The sand had filled up +all the cavities and cancelli, but was in no instance consolidated or +aggregated together; it was, therefore, easily removed by a soft brush, and +the bones perfectly cleared without injury. + +The spot whence these precious relics of the colossal birds that once +inhabited the islands of New Zealand were obtained, is a flat tract of land, +near the embouchure of a river, named Waingongoro, not far from Wanganui, +which has its rise in the volcanic regions of Mount Egmont. The natives +affirm that this level tract was one of the places first dwelt upon by their +remote ancestors; and this tradition is corroborated by the existence of +numerous heaps and pits of ashes and charred bones indicating ancient fires, +long burning on the same spot. In these fire-heaps Mr. Mantell found burned +bones of 'men, moas', and 'dogs'. + +The fragments of egg-shells, imbedded in the ossiferous deposits, had +escaped the notice of all previous naturalists. They are, unfortunately, +very small portions, the largest being only four inches long, but they +afford a chord by which to estimate the size of the original. Mr. Mantell +observes that the egg of the Moa must have been so large that a hat would +form a good egg-cup for it. These relics evidently belong to two or more +species, perhaps genera. In some examples the external +p 362 +surface is smooth; in others it is marked with short intercepted linear +grooves, resembling the eggs of some of the Struthiouidae, but distinct from +all known recent types. In this valuable collection only one bone of a +mammal has been detected, namely, 'the femur of a dog'. + +An interesting memoir on the probable geological position and age of the +ornithic bone deposits of New Zealand, by Dr. Mantell, based on the +observations of his enterprising son, it published in the Quarterly Journal +of the Geological Society of London (1848). It appears that in many +instances the bones are imbedded in sand and clay, which lie beneath a thick +deposit of volcanic detritus, and rest on an argillaceous stratum abounding +in marine shells. The specimens found in the rivers and streams have been +washed out of their banks by the currents which now flow through channels +from ten to thirty feet deep, formed in the more ancient alluvial soil. Dr. +Mantell concludes that the islands of New Zealand were densely peopled at a +period geologically recent, though historically remote, by tribes of +gigantic brevi-pennate birds allied to the ostrich tribe, all, or almost +all, of species and genera now extinct; and that, subsequently to the +formation of the most ancient ornithic deposit, the sea-coast has been +elevated from fifty to one hundred feet above its original level; hence the +terraces of shingle and loam which now skirt the maritime districts. The +existing rivers and mountain torrents flow in deep gulleys which they have +eroded in the course of centuries in these pleistocene strata, in like +manner as the river courses of Auvergne, in Central France, are excavated in +the mammiferous tertiary deposits of that country. The last of the gigantic +birds were probably exterminated, like the dodo, by human agency: some +small species allied to the apteryx may possibly be met with in the +unexplored parts of the middle island. + + +THE DODO. -- A most valuable and highly interesting history of the dodo and +its kindred* has recently appeared in which the history, affinities, and +osteology of the 'Dodo, Solitaire', and other extinct birds of the islands +Mauritius, Rodriguez, and Bourbon are admirably elucidated by H. G. +Strickland (of Oxford), and Dr. G. A. Melville. + + +[footnote] *'The Dodo and its Kindred'. By Messrs. Strickland and +Melville. 1 vol. 4to. with numerous plates. Reeves, London, 1848. + + +The historical part is by the former, the osteological and physiological +portion by the latter eminent anatomist. We would earnestly recommend the +reader interested in the most perfect history that has ever appeared, of the +extinction of a race of large animals, of which thousands existed but three +centuries ago, to refer to the original work. We have only space enough to +state that the authors have proved, upon the most incontrovertible evidence, +that the dodo was neither a vulture, ostrich, nor galline, as previously +anatomists supposed, but a 'frugiverous pigeon'. + +This section from pp 363-379 of: + +COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 +by Alexander von Humboldt + +Translated by E C Otte + +from the 1858 Harper & Brothers edition of Cosmos, volume 1 +-------------------------------------------------- + +p 363 +INDEX TO VOL. I. +------------------- + +ABICH, Hermana, structural relations of volcanic rocks, 234. + +Acosta, Joseph de, Historia Natural de las Indias, 66, 193. + +Adams, Mr., planet Neptune. See note by Translator, 90, 91. + +Aegos Potamos, on the aerolite of, 117, 122. + +Aelian on Mount Aetna, 227. + +Aerolites (shooting stars, meteors, meteoric stones, fire-balls, etc), +general description of, 111-137; physical character, 112-123; dates of +remarkable falls, 114, 115; their planetary velocity, 116-120; ideas of the +ancients on, 115, 116; November and August periodic falls of shooting stars, +118-120, 124-126; their direction from one point in the heavens, 120; +altitude, 120; orbit, 127; Chinese notices of, 128; media of communication +with other planetary bodies, 136; their essential difference from comets, +137; specific weights, 116, 117; large meteoric stones on record, 117; +chemical elements, 117, 129-131; crust, 129, 130; deaths occasioned by, 135. + +Aeschylus, "Prometheus Delivered," 115. + +Aetna, Mount, its elevation, 28, 229; supposed extinction by the ancients, +227; its eruptions from lateral fissures, 229; similarity of its zones of +vegetation to those of Ararat, 347. + +Agassiz, Researches on Fossil Fishes, 46, 273-277. + +Alexander, influence of his campaigns on physical science, 353. + +Alps, the, elevation of, 28, 29. + +Amber, researches on its vegetable origin, 284; Goppert on the amber-tree of +the ancient world (Pinites succifer), 283. + +Ampere, Andre Marie, 58, 193, 236. + +Anaxagoras on aerolites, 122; on the surrounding ether, 134. + +Andes, the, their altitude, etc. See Cordilleras. + +Anghiera, Peter Martyr de, remarked that the palmeta and pineta were found +associated together, 282, 283; first recognized (1510) that the limit of +perpetual snow continues to ascend as we approach the equator, 329. + +Animal life, its universality, 342-345; as viewed with microscopic powers of +vision, 341-346; rapid propagation and tenacity of life in animalcules, +344-346; geography of, 341-346. + +Anning, Miss Mary, discovery of the ink bag of the sepia, and of coprolites +of fish, in the lias of Lyme Regis, 271, 272. + +Austed's, D. R., "Ancient World." See notes by Translator, 271, 272, 274, +281, 287. + +Aplan, Peter, on comets, 101. + +Apollonius Myndius, described the paths of comets, 103. + +Arago, his ocular micrometer, 39; chromatic polarization, 52; optical +considerations, 85; on comets, 99-106; polarization experiments on the light +of comets, 105; aerolites, 114; on the November fall of meteors, 124; +zodiacal light, 143; motion of the solar system, 146, 147; on the increase +of heat at increasing depths, 173, 174; magnetism of rotation, 179, 180; +horary observations of declination at Paris compared with simultaneous +perturbations at Kasan, 191; discovery of the influence of magnetic storms +on the course of the needle, 194, 195; on south polar bands, 198; on +terrestrial light, 202; phenomenon of supplementary rainbows, 220; observed +the deepest Artesian wells to be the warmest, 223; explanation of the +absence of a refrigeration of temperature in the lower strata of the +Mediterranean, 303; observations on the mean annual quantity of rain in +Paris, 333; his investigations on the evolution of lightning, 337. + +Argelander on the comet of 1811, 109; on the motion of the solar system, +146, 149; on the light of the Aurora, 195, 196. + +Aristarchus of Samos, the pioneer of the Copernican system, 65. + +Aristotle, 65; his definition of Cosmos, 69; use of the term history, 75; on +comets, 103, 104; on the Ligyan field of stones, 115; aerolites, 122; on the +stone of Aegos Potamos, 135; aware that noises sometimes existed without +earthquakes, 209; his account of the upheavals of islands of eruption, 241; +"spontaneous motion," 341; noticed the redness assumed by long fallen snow, +344. + +Artesian wells, temperature of, 174, 223. + +Astronomy, results of, 38-40; phenomena of physical astronomy, 43, 44. + +Atmosphere, the general description of, 311, 316; its composition and +admixture, 312; variation of pressure, 313-317; climatic distribution of +heat, 313, 317-328; distribution of humidity, 313, 328, 334; electric +condition, 314, 335-338. + +p 363 +August, his psychometer, 332. + +Augustine, St., his views on spontaneous generation, 345, 346. + +Aurora Borealis, general description of 193-202; origin and course, 195, +196; altitude, 199; brilliancy coincident with the fall of shooting stars, +126, 127; whether attended with crackling sound, 199, 200; intensity of the +light, 201. + +Bacon, Lord, 53, 58; Novum Organon, 290. + +Baer, Von, 337. + +Barometer, the increase of its height attended by a depression of the level +of the sea, 298; horary oscillations of, 314, 315 + +Batten, Mr., letter on the snow-line of the two sides of the Himalayas, 331, +332. + +Beaufort, Capt., observed the emissions of inflammable gas on the Caramanian +coast, as described by Pliny, 223. See also, note by Translator, 223. + +Beaumont, Elie de, on the uplifting of mountain chains, 51, 300; influence +of the rocks of melaphyre and serpentine, on pendulum experiments, 167; +conjectures on the quartz strata of the Col de la Poissoniere, 266. + +Baccaria, observation of steady luminous appearance in the clouds, 202; of +lightning clouds, unaccompanied by thunder or indication of storm, 337. + +Beechey, Capt., 97; observations on the temperature and density of the water +of the ocean under different zones of longitude and latitude, 306. + +Bembo, Cardinal, his observations on the eruptions of Mount Aetna, 229; +theory of the necessity of the proximity of volcanoes to the sea, 243; +vegetation on the declivity of Aetna, 347. + +Berard, Capt., shooting stars, 119. + +Berton, Count, his barometrical measurements of the Dead Sea, 296. + +Berzelins on the chemical elements of aerolites, 130, 131. + +Benzenberg on meteors and shooting stars, 119, 120; their periodic return in +Autgust, 125. + +Bessel's theory on the oscillations of the pendulum, 44; pendulum +experiments, 64; on the parallax of 61 Cygni, 88; on Halley's comet, 102, +103, 104; on the ascent of shooting stars, 123; on their partial visibility, +128; velocity of the sun's translatory motion, 145; mass of the star 61 +Cygni, 148; parallaxes and distances of fixed stars, 153; comparison of +measurements of degrees, 165, 166. + +Biot on the phenomenon of twilight, 118; on the zodical light, 141; pendulum +experiments at Bordeaux, 170. + +Biot, Edward, Chinese observations of comets, 101, 109; of aerolites, 128. + +Bischof on the interior heat of the globe, 217, 219, 235, 244, 294. + +Blumenbach, his classification of the races of men, 356. + +Bockh, origin of the ancient myth of the Nemean lunar lion, 134, 135. + +Boguslawski, falls of shooting stars, 119, 128. + +Bonpland, M., and Humboldt, on the pelagic shells found on the ridge of the +Andes, 45. + +Boussingault, on the depth at which is found the mean annual temperature +within the tropics, 175; on the volcanoes of New Granada, 217; on the +temperature of the earth in the tropics, 220, 221; temperature of the +thermal springs of Las Trincheras, 222; his investigations on the chemical +analysis of the atmosphere, 311, 312; on the mean annual quantity of rain in +different parts of South America, 333, 334. + +Bouvard, M., 105; his observations on that portion of the horary +oscillations of the pressure of the atmosphere, which depends on the +attraction of the moon 313. + +Bramidos y truenos of Guanaxuato, 209, 210. + +Brandes, falls of shooting stars, 114, 116; height and velocity of shooting +stars, 120; their periodic falls, 125, 126. + +Bravais, on the Aurora, 201; on the daily oscillations of the barometer in +70 degrees north latitude, 314; distribution of the quantity of rain in +Central Europe, 334; doubts on the greater dryness of mountain air, 334. + +Brewster, Sir David, first detected the connection between the curvature of +magnetic lines and my isothermal lines, 193. + +Brongniart, Adolphe, luxuriance of the primitive vegetable world, 218; +fossil flora contained in coal measures, 280. + +Brongniart, Alexander, formation of ribbon jasper, 259; one of the founders +of the archaeology of organic life, 273. + +Brown, Robert, first discoverer of molecular motion, 341. + +Buch's, Leopold von, theory on the elevation of continents and mountain +chains, 45; on the craters and circular form of the island of Palma, 226; on +volcanoes, 234, 238, 242, 243, 247; on metamorphic rocks, 249-252, 260, 263, +264; on the origin of various conglomerates and rocks of detritus, 269; +classification of ammonites, 276, 277; physical causes of the elevation of +continents, 295; on the changes in height of the Swedish coasts, 295. + +Buckland, 272; on the fossil flora of the coal measures, 279. + +Buffon, his views on the geographical distribution of animals, 348. + +Burckhardt, on the volcano of Medina, 246; on the hornitos de Jerullo, see +note by Translator, 230. + +Burnes, Sir Alexander, on the purity of the atmosphere in Bokhara, 114; +propagation of shocks of earthquakes, 212. + +p 365 +Caile, La, pendulum measurements at the Cape of Good Hope, 169. + +Caldas, quantity of rain at Santa Fe de Bogota, 334. + +Camargo's MS. 'Historia de Tiascala', 140. + +Capocci, his observations on periodic falls of aerolites, 126. + +Carlini, geodesic experiments in Lombardy, 168; Mount Cenis, 170. + +Carrara marble, 262, 263. + +Carus, his definition of "Nature," 41. + +Caspian Sea, its periodic rise and fall, 297. + +Cassini, Dominicus, on the zodiacal light, 139, 140; hypothesis on 141; his +discovery of the spheroidal form of Jupiter, 164. + +Cautley, Capt, and Dr. Falconer, discovery of gigantic fossils in the +Himalayas. + +Cavanilles, first entertained the idea of seeing grass grow, 149. + +Cavendish, use of the torsion balance to determine the mean density of the +Earth, 170. + +Challis, Professor, on the Aurora, March 19 and Oct. 24th, 1847, see note by +Translator, 195, 199. + +Chardin, noticed in Persia the famous comet of 1608, called "nyzek" or +"petite lance," 139. + +Charpentier, M., belemnites found in the primitive limestone of the Col de +la Seigne, 261; glaciers, 329. + +Chemistry as distinguished from physics, 62; chemical affinity, 63. + +Chevandier, calculations on the carbon contained in the trees of the forests +of our temperate zones, 281. + +Childrey first described the zodical light in his Britannia Baconica, 138. + +Chinese accounts of comets, 99, 100, 101; shooting stars, 128: "fire +springs," 158; knowledge of the magnetic needle, 180; electro-magnetism, +188, 189. + +Chladni on meteoric stones, etc., 118, 135; on the selenic origin of +aerolites, 121; on the supposed phenomenon of ascending shooting stars, 122; +on the obscuration of the Sun's disk, 133; sound-figures, 135; pulsations in +the tails of comets, 143. + +Choiseul, his chart of Lemnos, 246. + +Chromatic polarization. See Polarization. + +Cirro-cumulus cloud. See Clouds. + +Cirrous Strata. See Clouds. + +Clark, his experiments on the variations of atmospheric electricity, 335, +336. + +Clarke, J. G., of Maine, U.S., on the comet of 1843, 100. + +Climatic distribution of heat, 313, 317-328; of humidity, 328, 333, 334. + +Climatology, 317-329; climate, general sense of, 317, 318. + +Clouds, their electric tension, color, and height, 236, 337; connection of +cirrous strata with the Aurora Borealis, 196; cirro-cumulus cloud, phenomena +of, 197; luminous, 202; Dove on their formation and appearance, 315, 316; +often present on a bright summer sky the "projected image" of the soil +below, 316; volcanic, 233. + +Coal formations, ancient vegetable remains in, 280, 281. + +Coal mines, depth of, 158-160. + +Colebrooke on the snow-line of the two sides of the Himalayas, 31. + +Colladon, electro-magnetic apparatus, 335. + +Columbus, his remark that "the Earth is small and narrow," 164; found the +compass showed no variation in the Azores, 181, 182; of lava streams, 245; +noticed conifers and palms growing together in Cuba, 282; remarks in his +journal on the equatorial currents, 307; of the Sargasso Sea, 308; his +dream, 310, 311. + +Comets, general description of, 99-112; Biela's 43, 86, 107, 108; Blaupain's +108; Clausen's 108; Encke's, 43, 64, 86, 107-108; Faye's 107, 108; Halley's, +43, 100, 102-109; Lexell's and Burchardt's 108, 110; Messier's 108; +Olbera's, 109; Pons's 109; famous one of 1608, seen in Persia, called +"nyzek," or "petit lance," 189; comet of 1843, 101; their nucleus and tail, +87, 100; small mass, 100; diversity of form, 100-103; light, 104-106; +velocity, 109; comets of short period, 107-109; long period, 109-110; +number, 99; Chinese observations on, 99-101; value of a knowledge of their +orbits, 43; possibility of collision of Blela's and Encke's comets, 107, +108; hypothesis of a resisting medium conjectured from the diminishing +period of the revolution of Encke's comet, 106; apprehensions of their +collision with the Earth, 108, 110, 111; their popular supposed influence on +the vintage, 111. + +Compass, early use of by the Chinese, 180; permanency in the West Indies, +181. + +Condamine, La, inscription on a marble tablet at the Jesuit's College, Quito +on the use of the pendulum as a measure of seconds, 166, 167. + +Conde, notice of a heavy shower of shooting stars, Oct., 902, 119. + +Coraboeuf and Delcrois, geodetic operations, 304. + +Cordilleras, scenery of, 26, 29, 33; vegetation, 34, 35; intensity of the +zodiacal light, 137. + +Cosmography, physical, its object and ultimate aims, 57-60; materials, 60. + +Cosmos, the author's object, 38, 78; primitive signification and precise +definition of the word, 69; how employed by Greek and Roman writers, 69, 60; +derivation, 70. + +Craters. See Volcanoes. + +Curtius, Professor, his notes on the temperature of various springs in +Greece, 222, 223. + +Cuvier, one of the founders of the archaeology of organic life, 273; +discovery of fossil crocodiles in the tertiary formations, 274. +Dainachos on the phenomena attending the fall of the stone of Aegos Potamos, +133, 134. + +Dalman on the existence of Chionaea araneoides in polar snow, 344. + +Dalton, observed the southern lights in England, 198. + +Dante, quotation from, 322. + +Darwin, Charles, fossil vegetation in the travertine of Van Diemen's Land, +224; central volcanoes regarded as volcanic chains of small extent on +parallel fissures, 238; instructive materials in the temperate zones of the +southern hemisphere for the study of the present and past geography of +plants, 282, 283; on the fiord formation at the southeast end of America, +293; on the elevation and depression of the bottom of the South Sea, 297; +rich luxuriance of animal life in the ocean, 309, 310; on the volcano of +Aconcagua, 330. + +Daubeney on volcanos. See Translator's notes, 161, 203, 204, 210, 218, 224, +228, 230, 233, 234, 235, 236, 244, 245. + +Daussy, his barometric expriments, 208; observations on the velocity of the +equatorial current, 307. + +Davy, Sir Humphrey, hypothesis on active volcanic phenomena, 235; on the low +temperature of water on shoals, 309. + +Dead Sea, its depression below the level of the Mediterranean, 296, 297. + +Dechen, Von, on the depth of the coal-basin of Liege, 160. + +Delcrois. See Coraboeuf. + +Descartes, his fragments of a contemplated work, entitled "Monde," 68; on +comets, 139. + +Deshayes and Lyell, their investigations on the numerical relations of +extinct and existing organic life, 275. + +Dicaearchus, his "parallel of the diaphragm," 289. + +Diogenes Laertius, on the aerolite of Aegos Potamos, 116, 122, 134. + +D'Orbigny, fossil remains from the Himalaya and the Indian plains of Cutch, +277. + +Dove on the similar action of the declination needle to the atmospheric +electrometer, 194; "law of rotation," 315; on the formation and appearance +of clouds, 316; on the difference between the true temperature of the +surface of the ground and the indications of a thermometer suspended in the +shade, 325; hygrometric windrose, 333. + +Doyere, his beautiful experiments on the tenacity of life in animalcules, +345. + +Drake, shaking of the earth for successive days in the United States +(1811-12), 211. + +Dufrenoy et Elie de Beaumont, Geologie de la France, 253, 258, 259, 260, +262, 266. + +Dumas, results of his chemical analysis of the atmosphere, 311. + +Dunlop on the comet of 1825, 103. + +Duperrey on the configuration of the magnetic equator, 183; pendulum +oscillations, 166. + +Duprez, influence of trees on the intensity of electricity in the +atmosphere, 335. + +Eandi, Vassalli, electric perturbation during the protracted earthquake of +Pignorol, 206. + +Earth, survey of its crust, 72; relative magnitude, etc., in the solar +system, 95-97; general description of terrestrial phenomena, 154-360; +geographical distribution, 161, 162; its mean density, 169-172; internal +heat and temperature, 172-176; electro-magnetic activity, 177-193; +conjectures on its early high temperature, 172; interior increase of heat +with increasing depth, 161; greatest depths reached by human labor, 157-159; +methods employed to investigate the curvature of its surface, 165-168; +reaction of the interior on the external crust, 161, 202-247; general +delineation of its reaction, 204-206; fantastic views on its interior, 171. + +Earthquakes, general account of, 204-218; their manifestations, 204-206; of +Riobamba, 204, 206, 208, 212, 214; Lisbon, 210, 211, 213, 214; Calabria, +206; their propagation, 204, 212, 213; waves of commotion, 205, 206, 212; +action on gaseous and aqueous springs, 210, 222, 224; salses and mud +volcanoes, 224-228; erroneous popular belief on, 206-208; noise accompanying +earthquakes, 208-210; their vast destruction of life, 210, 211; volcanic +force, 214, 215; deep and peculiar impression produced on men and animals, +215, 216. + +Ehrenberg, his discovery of infusoria in the polishing slate of Bilin, 150; +infusorial deposits, 255, 262; brilliant discovery of microscopic life in +the ocean and in the ice of the polar regions, 342; rapid propogation of +animalcules and their tenacity of life, 343-345; transformation of chalk, +262. + +Electricity, magnetic, 188-202; conjectured electric currents, 189, 190; +electric storms, 194; atmospheric 335, 337. + +Elevations, comparative, of mountains in the two hemispheres, 28, 29. + +Encke, 106; his computation that the showers of meteors, in 1833, proceeded +from the same point of space in the direction in which the earth was moving +at the time, 119, 120. + +Ennius, 71. + +Epicharmus, writings of, 71. + +Equator, advantages of the countries bordering on, 33, 34; their organic +richness and fertility, 34, 35; magnetic equator, 183-185. + +Erman, Adolph, on the three cold days of May (11th-13th), 133; lines of +declination in Northern Asia, 182; in the southern parts of the Atlantic, +187; observations during the earthquake of Irkutsk, on the non-disturbance +of the horary changes of the magnetic needle, 207. + +Eruptions and exhalations (volcanic), lava, gaseous and liquid fluids, hot +mud, mud mofettes, etc., 161, [other page numbers obscured in paper copy] + +p 367 +Ethnographical studies, their importance and teaching, 357, 358. + +Euripides, his Phaeton, 122. + +Falconer, Dr., fossil researches in the Himalayas, 278. + +Faraday, radiating heat, electro-magnetism etc., 49, 179, 188; brilliant +discovery of the evolution of light by magnetic forces, 193. + +Farquharson on the connection of cirrous clouds with the Aurora, 197; its +altitude, 199. + +Federow, his pendulum experiments, 168. + +Feldt on the ascent of shooting stars, 123. + +Ferdinandes, igneous island of, 242. + +Floras, geographical distribution of, 350. + +Forbes, Professor E., reference to his Travels in Lycia, 223; account of the +island of Santorino, 241, 242. + +Forbes, Professor J., his improved selsmometer, 205; on the correspondence +existing between the distribution of existing floras in the British Islands, +348, 349; on the origin and diffusion of the British flora, 353, 354. + +Forster, George, remarked the climatic difference of temperature of the +eastern and western coasts of both continents, 321. + +Forster, Dr. Thomas, monkish notice of "Meteorodes," 123. + +Fossil remains of tropical plants and animals found in northern regions, 46, +270-284; of extinct vegetation in the travertine of Van Diemen's Land, 224; +fossil human remains, 250. + +Foster, Reinhold, pyramidal configuration of the southern extremities of +continents, 290, 291. + +Fourier, temperature of our planetary system, 155, 172, 176. + +Fracastoro on the direction of the tails of comets from the sun, 101. + +Fraehn, fall of stars, 119. + +Franklin, Benjamin, existence of sandbanks indicated by the coldness of the +water over them, 308. + +Franklin, Capt., on the Aurora, 197, 199, 200, 201; rarity of electric +explosions in high northern regions, 337. + +Freycinet, pendulum oscillations, 166. + +Fusinieri on meteoric masses, 123. + +Galileo, 104, 167. + +Galle, Dr., 91. + +Galvant, Aloysio, accidental discovery of galvanism, 52. + +Gaseous emanations, fluids, mud, and molten earth, 217, 220. + +Gasparin, distribution of the quantity of rain in Central Europe, 333. + +Gauss, Friedrich, on terrestrial magnetism, 179; his erection. in 1832, of a +magnetic observatory on a new principle, 191, 192. + +Gay-Lussac, 204, 233, 234, 266, 267, 311, 312, 334, 336. + +Geognostic or geological description of the earth's surface, 202-286. + +Geognosy (the study of the textures and position of the earth's surface), +its progress, 203. + +Geography, physical, 288-311; of animal life, 341-346; of plants, 346-351. + +Geographics, Ritter's (Carl), "Geography in relation to Nature and the +History of Man," 48, 67; Varenius (Bernhard), General and Comparative +Geography, 66, 67. + +Gerard, Capts. A. G. and J. G., on the snow-line and vegetation of the +Himalayas, 31, 32, 331, 332. + +German scientific works, their defects, 47. + +Geyser, intermittent fountains of, 222. + +Gieseke on the Aurora, 200. + +Gilbert, Sir Humphrey, Gulf Stream, 307. + +Gilbert, William, of Colchester, terrestrial magnetism, 158, 159, 177, 179, +182. + +Gillies, Dr., on the snow-line of South America, 330, 331. + +Gioja, crater of, 98. + +Girard, composition and texture of basalt, 253. + +Glaisher, James, on the Aurora Borealis of Oct. 24, 1847. See Translator's +notes, 194, 200. + +Goldfuss, Professor, examination of fossil specimens of the flying saurians, +274. + +Goppert on the conversion of a fragment of amber-tree into black coal, 281; +eyeadeae, 283; on the amber-tree of the Baltic, 283, 284. + +Gothe, 41, 47, 53. + +Greek philosophers, their use of the term Cosmos, 69, 70; hypotheses on +aerolites, 122, 123, 134. + +Grimm, Jacob, graceful symbolism attached to falling stars in the Lithuanian +mythology, 112, 113. + +Gulf Stream, its origin and course, 307. + +Gumprecht, pyroxenic nepheline, 253. + +Guanaxuato, striking subterranean noise at, 209. + +Hall, Sir James, his experiments on mineral fusion, 262. + +Halley, comet, 43, 100, 102-109; on the meteor of 1686, 118, 133; on the +light of stars, 152; hypothesis of the earth being a hollow sphere, 171; his +bold conjecture that the Aurora Borealis was a magnetic phenomenon, 193. + +Hansteen on magnetic lines of declination in Northern Asia, 182. + +Hausen on the material contents of the moon, 96. + +Hedenstrom on the so-called "Wood Hills" of New Siberia, 281. + +Hegel, quotation from his "Philosophy of History," 76. + +Heine, discovery of crystals of feldspar in scoriae, 268. + +Hemmer, falling stars, 119. + +Hencke, planets discovered by. See note by Translator, 90, 91. + +Henfrey, A., extract from his Outlines of Structural and Physiological +Botany. See notes by Translator, 341, 342, 351. + +p 368 +Hensius on the variations of form in the comet of 1744, 102. + +Herodotus, described Scythia as free from earthquakes, 204; Scythian saga of +the sacred gold, which fell burning from heaven, 115. + +Herschel, Sir William, map of the world, 66; inscription on his monument at +Upton, 87; satellites of Saturn, 96; diameters of comets, 101; on the comet +of 1811, 103; star guagings, 150; starless space, 150, 152; time required +for light to pass to the earth from the remotest luminous vapor, 154. + +Herschel, Sir John, letter on Magellanic clouds, 85; satellites of Saturn, +98; diameter of nebulous stars, 141; stellar Milky Way, 150, 151; light of +isolated starry clusters, 151; observed at the Cape, the star pi in Argo +increase in splendor, 153; invariability of the magnetic declination in the +West Indes, 181. + +Hesiod, dimensions of the universe, 154. + +Hevellus on the comet of 1618, 106. + +Hibbert, Dr., on the Lake of Laach. See note by Translator, 218. + +Himalayas, the, their altitude, 28; scenery and vegetation, 29, 30; +temperature, 30, 31; variations of the snow-line on their northern and +southern declivities, 30-33, 331. + +Hind, Mr., planets discovered by. See Translator's note, 90, 91. + +Hindoo civilization, its primitive seat, 35, 36. + +Hippalos, or monsoons, 316. + +Hippocrates, his erroneous supposition that the land of Scythia is an +elevated table-land, 346. + +Hoff, numerical inquiries on the distribution of earthquakes throughout the +year, 207. + +Hoffman, Friedrich, observations on earthquakes, 206-207; on eruption +fissures in the Lipari Islands, 238. + +Holberg, his Satire, "Travels of Nic. Klimius, in the world under ground." +See Translator's note, 171, 172. + +Hood on the Aurora, 200, 201. + +Hooke, Robert, pulsations in the tails of comets, 143; his anticipation of +the application of botannical and zoological evidence to determine the +relative age of rocks, 270-272. + +Ho-tsings, Chinese fire-springs, their depth, 158; chemical composition, 217. + +Howard on the climate of London, 125; mean annual quantity of rain in +London, 333. + +Hugel, Carl von, on the elevation of the valley of Kashmir, 32, 33; on the +snow-line of the Himalayas, 331. + +Humboldt, Alexander von, works by referred to in various notes: + Annales de Chimie et de Physique, 31, 305. + Annales des Science Naturelles, 28. + Ansichten der Natur, 342, 344, 347. + Asie Centrale, 28, 31, 33, 115, 158, 159, 160, 204, 217, 219, 225, 245, +251, 252, 260, 289, 290, 291, 292, 296, 300, 301, 303-306, 320, 323, 324, +330, 331, 334, 350, 356. + Atlas Geographique et Physique du Nouveau Continent, 33, 249. + De distributione Geographica Plantrum, secundum coeli temperiem, et +altitudinem Montium, 33, 291, 324. + Examen Critique de l'Histoire de la Geographie, 58, 180, 181, 227, 289, +292, 307, 308, 310, 316, 356. + Essai Geognostique sur le Gisement des Roches, 230, 252, 266, 300. + Essai Politique sur la Nouvelle Espagne, 129, 240. + Essai sur la Geographie des Plantes, 33, 230, 315. + Flora Friburgensis Subterranea, 340, 346. + Journal de Physique, 178, 292. + Lettre au Duc de Sussex, sur les Moyens propres a perfectionner la +connaissance du Magnetisme Terrestre, 178, 192. + Monumens des Peuples Indigenes de l'Amerique, 140. + Nouvelles Annales des Voyages, 307. + Recueil d'Observations Astronomiques, 28, 167, 218, 327. + Recueil d'Observations de Zoologi et d'Anatomie Comparee, 232. + Relation Historique du Voyage aux Regions Equinoxiales, 113, 119, 123, +127, 130, 186, 206, 207, 220, 221, 225, 252, 292, 299, 300, 302, 305-307, +314, 315, 327, 329, 334, 336. + Tableau Physique des Regions Equinoxiales, 33, 230. + Vues des Cordilleres, 225, 230. + +Humboldt, Wilhelm von, on the primitive seat of Hindoo civilization, 36; +sonnet, extract from, 154; on the gradual recognition by the human race of +the bond of humanity, 358, 359. + +Humidity, 313, 332-335. + +Hutton, Capt. Thomas, his paper on the snow-line of the Himalayas, 331, 332. + +Huygens, polarization of light, 52; nebulous spots, 138. + +Hygrometry, 332, 333; hygrometric wind-rose, 333. + +Imagination, abuse of, by half-civilized nations, 37. + +Imbert, his account of Chinese "fire-springs," 158. + +Ionian school of natural philosophy, 65, 77, 84, 134. + +Isogenic, isoclinical, isodynamic, etc. See Lines. + +Jacquemont, Victor, his barometrical observations on the snow-line of the +Himalayas, 32, 231. + +Jasper, its formation, 259-261. + +Jessen on the gradual rise of the coast of Sweden, 295. + +Jorullo, hornitos de, 230. + +p 369 +Justinian, conjectures on the physical causes of volcanic eruptions, 243. + +Kamtz, isobarometric lines, 315; doubts on the greater dryness of mountain +air, 334. + +Kant, Emmanuel, "on the theory and structure of the heavens," 50, 65; +earthquake at Lisbon, 210. + +Kelihau on the ancient sea-line of the coast of Spitzbergen, 296. + +Kepler on the distances of stars, 88; on the density of the planets, 93; law +of progression, 95; on the number of comets, 99; shooting stars, 113; on the +obscuration of the sun's disk, 132; on the radiations of heat from the fixed +stars, 136; on a solar atmosphere, 139. + +Kloden, shooting stars, 119, 124. + +Knowledge, superficial, evils of, 43. + +Krug of Nidda, temperature of the Geyser and the Strokr intermittent +fountains, 222. + +Krusenstern, Admiral, on the train of a fire-ball, 114. + +Kuopho, a Chinese physicist on the attraction of the magnet, and of amber, +168. + +Kupffer, magnetic stations in Northern Asia, 191. + +Lamanon, 187. + +Lambert, suggestion that the direction of the wind be compared with the +height of the barometer, alterations of temperature, humidity, etc., 315. + +Lamont, mass of Uranus, 93; satellites of Saturn, 96. + +Language and thought, their mutual alliance, 56; author's praise of his +native language, 56. + +Languages, importance of their study, 357, 359. + +Laplace, his "Systeme du Monde," 48, 62, 92, 141; mass of the comet of 1770, +107; on the required velocity of masses projected from the Moon, 121, 122; +on the altitude of the boundaries of the atmosphere of cosmical bodies, 141; +zodiacal light, 141; lunar inequalities, 166; the Earth's form and size +inferred from lunar inequalities, 168, 169; his estimate of the mean height +of mountains, 301; density of the ocean required to be less than the earth's +for the stability of its equilibrium, 305; results of his perfect theory of +tides, 306. + +Latin writers, their use of the term "Mundus," 70, 71. + +Latitudes, Northern, obstacles they present to a discovery of the laws of +Nature, 36; earliest acquaintance with the governing forces of the physical +world, there displayed, 36; spread from thence of the germs of civilization, +36. + +Latitudes, tropical, their advantages for the contemplation of nature, 33; +powerful impressions, from their organic richness and fertility, 34; +facilities they present for a knowledge of the laws of nature, 35; brilliant +display of shooting stars, 113. + +Laugier, his calculations to prove Halley's comet identical with the comet +of 1378, described in Chinese tables, 109. + +Lava, its mineral composition, 234. + +Lavoisier, 62. + +Lawrence (St.), fiery tears, 124; meteoric stream, 125. + +Leibnitz, his conjecture that the planets increase in volume in proportion +to their increase of distance from the Sun, 93. + +Lenz, observations on the mean level of the Caspian Sea, 297; maxims of +density of the oceanic temperature, 304; temperature and density of the +ocean under different zones of latitude and longitude, 306. + +Leonhard, Karl von, assumption on formations of granular limestone, 263. + +Leverrier, planet Neptune. See Translator's note, 90, 91. + +Lewy, observations on the varying quantity of oxygen in the atmosphere, +according to local conditions, or the seasons, 311, 312. + +Lichtenberg, on meteoric stones, 118. + +Liebig on traces of ammonical vapors in the atmosphere, 311. + +Light, chromatic polarization of, 52; transmission, 88; of comets, 104-106; +of fixed stars, 105; extraordinary lightness, instances of, 142-144; +propagation of 153; speed of transit, 153, 154. See Aurora, Zodiacal Light, +etc. + +Lignites or beds of brown coal, 283, 284. + +Lines, isogonic (magnetic equal deviation), 177, 181-185; isoclinal +(magnetis equal inclination), 178, 179, 181-185; isodynamic (or magnetic +equal force), 181, 185-194; isogeothermal (chthonisothermal), 219; +isobarometric, 315; isothermal, isotheral, and isochimenal, 317, 327, 328, +358. + +Line of no variation of horary declination, 183; lower limit of perpetual +snow, 329-332; phosphorescent, 113. + +Lisbon, earthquake of, 210, 211, 213, 214. + +Lord on the limits of the snow-line on the Himalayas, 32. + +Lottin, his observations of the Aurora, with Bravais and Siljerstrom, on the +coast of Lapland, 195, 200, 201. + +Lowenorn, recognized the coruscation of the polar light in bright sunshine, +196. + +Lyell, Charles, investigations on the numerical relations of extinct and +organic life, 274, 275; nether-formed or hypogene rocks, 249; uniformity of +the production of erupted rocks, 257. See notes by Translator, 203, 244, +257. + +Mackenzie, description of a remarkable eruption in Iceland, 236. + +Maclear on a Centauri, 88; parallaxes and distances of fixed stars, 153; +increase in brightness of 'pi' Argo, 153. + +Madler, planetary compression of Uranus, 96; distance of the innermost +satellite of Saturn from the centre of that planet, 97; material contents of +the Moon, 96; its libration, 98; mean depression of temperature on the three +cold days of May (11th-13th), 133; conjecture that the average mass of the +larger number of binary stars exceeds the mass of the Sun, 149. + +Magellanic clouds, 85. + +Magnetic attraction, 188; declination, 181-183; horary motion, 177-180; +horary variations 183, 190; magnetic storms, 177, 179, 195, 199; their +intimate connection with the Aurora, 193-201; represented by three systems +of lines, see Lines; movement of oval systems, 182; magnetic equator, +183-185; magnetic poles, 183, 184; observatories, 190-192; magnetic +stations, 190, 191, 317. + +Magnetism, terrestrial, 177-193, 201; electro, 177-191. + +Magnussen, Soemund, description of remarkable eruption in Iceland, 236. + +Mahlmann, Wilhelm, south west direction of the aërial current in the middle +latitudes of the temperate zone, 317. + +Mairan on the zodiacal light, 138, 139, 142; his opinion that the Sun is a +nebulous star, 141. + +Malapert, annular mountain, 98. + +Malle, Dureau de la, 223. + +Man, general view of, 351-359; proofs of the flexibility of his nature, 27; +results of his intellectual progress, 53, 54; geographical distribution of +races, 351-356; on the assumption of superior and inferior races, 351-358; +his gradual recognition of the bond of humanity, 358, 359. + +Mantell, Dr., his "Wonders of Geology," see notes by Translator, 45, 64, +203, 274, 278, 281, 283, 284, 287; "Medals of Creation," 46, 271, 283, 287. + +Margarita Philosophica by Gregory Reisch, 58. + +Marius, Simon, first described the nebulous spots in Andromeda and Orion, +138. + +Martins, observations on polar bands, 198; found that air collected at +Faulhorn contained as much oxygen as the air of Paris, 312; on the +distribution of the quantity of rain in Central Europe, 333; doubts on the +greater dryness of mountain air, 334. + +Matthessen, letter to Arago on the zodiacal light, 142. + +Mathieu on the augmented intensity of the attraction of gravitation in +volcanic islands, 167. + +Mayer, Tobias, on the motion of the solar system, 146, 148. + +Mean numerical values, their necessity in modern physical science, 81. + +Melloni, his discoveries on radiating heat and electro-magnetism, 49. + +Menzel, unedited work by, on the flora of Japan, 347. + +Messier, comet, 108; nebulous spot resembling our starry stratum, 151. + +Metamorphic Rocks. See Rocks. + +Meteorology, 311-339. + +Meteors, see Aërolites; meteoric infusoria, 345, 346. + +Methone, Hill of, 240. + +Meyen on forming a thermal scale of cultivation, 324; on the reproductive +organs of liverworts and algae, 341. + +Meyer, Hermann von, on the organization of flying saurians, 274. + +Milky Way, its figure, 89; views of Aristotle on, 103; vast telescopic +breadth, 150; Milky Way of nebulous spots at right angles with that of the +stars, 151. + +Minerals, artificially formed, 268, 269. + +Mines, greatest depth of, 157, 159; temperature, 158. + +Mist, phosphorescent, 142. + +Mitchell, protracted earthquake shocks in North America, 211. + +Mitscherlich on the chemical origin of iron glance in volcanic masses, 234; +chemical combinations, a means of throwing a clear light on geognosy, 256; +on gypsum, as a uniaxal crystal, 259; experiments on the simultaneously +opposite actions of heat on crystalline bodies, 259; formation of crystals +of mica, 260; on artificial mineral products, 268, 271. + +Mofettes (exhalations of carbonic acid gas), 215-219. + +Monsoons (Indian), 316, 317. + +Monticelli on the current of hydrochloric acid from the crater of Vesuvius, +235; crystals of mica found in the lava of Vesuvius, 260. + +Moon, the, its relative magnitude, 96; density, 96; distance from the earth, +97; its libration, 98, 163; its light compared with that of the Aurora, 201, +202; volcanic action in, 228. + +Moons or satellites, their diameter, distances, rotation, etc., 95-99. + +Morgan, John H. "on the Aurora Borealis of Oct. 24, 1847." See Translator's +notes, 194, 199. + +Morton, Samuel George, his magnificent work on the American Races, 362. + +Moser's images, 202. + +Mountains, in Asia, America, and Europe, their altitude, scenery, and +vegetation, 27-30, 238, 347; their influence on climate, natural +productions, and on the human race, its trade, civilization, and social +condition, 291, 292, 299, 300, 327; zones of vegetation on the declivities +of 29, 30, 327-329; snow-line of, 30-33, 330, 331. + +Mud volcanoes. See Salses and Volcanoes. + +Muller, Johannes, on the modifications of plants and aniimals within certain +limitations, 353. + +Muncke on the appearance of Auroras in certain districts, 198. + +Murchison, Sir R., account of a large fissure through which melaphyre had +been ejected, 258; classification of fossiliferous strata, 277; on the age +of the Palaeosaurus and Thecodontosaurus of Bristol, 274. + +Muschenbroek on the frequency of meteors in August, 125. + +Myndius, Apollonius, on the Pythagorean doctrine of comets, 103, 104. + +Nature, result of a rational inquiry into, 25; emotions excited by her +contemplation, 25; striking scenes, 26; their sources of enjoyment, 26, 27; +magnificence of the tropical scenery, 33, 34, 35, 344; religious impulses +from a communion with nature, 37; obstacles to an active spirit of inquiry, +37; mischief of inaccurate observations, 38; higher enjoyments of her study, +38; narrow-minded views of nature, 38; lofty impressions produced on the +minds of laborious observers, 40; nature defined, 41; her studies +inexhaustible, 41; general observations, their great advantages, 42; how to +be correctly comprehended, 72; her most vivid impressions earthly, 82. + +Nature, philosophy of, 24, 37; physical description of, 66, 67, 73. + +Nebulae, 84-86; nebulous Milky Way at right angles with that of the stars, +150-153; nebulous spots, conjectures on, 83-86; nebulous stars and planetary +nebulae, 85, 151, 152; nebulous vapor, 83-86, 87, 152; their supposed +condensation in conformity with the laws of attraction, 84. + +Neilson, gradual depression of the southern part of Sweden, 295. + +Nericat, Andrea de, popular belief in Syria on the fall of aerolites, 123. + +Newton, discussed the question on the difference between the attraction of +masses and molecular attraction, 63; Newtonian axiom confirmed by Bessel, +64; his edition of the Geography of Varenius, 66; Principia Mathematica, 67; +considered the planets to be composed of the same matter with the Earth, +132; compression of the Earth, 165. + +Nicholl, J. P., note from his account of the planet Neptune, 90, 91. + +Nicholson, observations of lighting clouds, unaccompanied by thunder or +indications of storm, 337. + +Nobile, Antonio, experiments of the height of the barometer, and its +influence on the level of the sea, 298. + +Noggerath counted 792 annual rings in the trunk of a tree at Bonn, 283. + +Nordmann on the existence of animalcules in the fluids of the eyes of +fishes, 345. + +Norman, Robert, invented the inclinatorium, 179. + +Observations, scientific, mischief of inaccurate, 38; tendency of +unconnected, 40. + +Ocean, general view of, 292-311; its extent as compared with the dry land, +288, 289; its depth, 160, 302; tides, 304, 305; decreasing temperature at +increased depths, 302; uniformity and constancy of temperature in the same +spaces, 303; its currents and their various causes, 306-309; its +phosphorescence in the torrid zone, 202; its action on climate, 303, +319-320; influence on the mental and social condition of the human race, +162, 291, 292, 294, 310; richness of its organic life, 300, 310; oceanic +microscopic forms, 342, 343; sentiments excited by its contemplation, 310. + +Oersted, electro-magnetic discoveries, 188, 191. + +Olbers, comets, 104, 109; aerolites, 114, 118; on their planetary velocity, +121; on the supposed phenomena of ascending shooting stars, 123; their +periodic return in August, 125; November stream, 126; prediction of a +brilliant fall of shooting stars in Nov., 1867, 127; absence of fossil +meteoric stones in secondary and tertiary formations, 131; zodiacal light, +its vibration through the tails of comets, 143; on the transparency of +celestial space, 152. + +Olmsted, Denison of New Haven, Connecticut, observations of aerolites, 113, +118, 119, 124. + +Oltmanns, Herr, observed continuously with Humboldt, at Berlin, the +movements of the declination needle, 190, 191. + +Ovid, his description of the volcanic Hill of Methone, 240. + +Oviedo describes the weed of the Gulf Stream as Praderias de yerva (sea weed +meadows), 308. + +Palaeontology, 270-284. + +Pallas, meteoric iron, 131. + +Palmer, New Haven, Connecticut, on the prodigious swarm of shooting stars, +Nov. 12 and 13, 1833, 124; on the non-appearance in certain years of the +August and November fall of aerolites, 129. + +Parallaxes of fixed stars, 88, 89; of the solar system, 145, 146. + +Perry, Capt., on Auroras, their connection with magnetic perturbations, 197, +201; whether attended with any sound, 200; seen to continue throughout the +day, 197; barometric observation at Port Bowen, 314, 315; rarity of electric +explosions in northern regions, 337. + +Patricius, St., his accurate conjectures on the hot springs of Carthage, +223, 224. + +Peltier on the actual source of atmospheric electricity, 335, 336. + +Pendulum, its scientific uses, 44; experiments with, 64, 166, 169, 170; +employed to investigate the curvature of the earth's surface, 165; local +attraction, its influence on the pendulum, and geognostic knowledge deduced +from, 44, 45, 167, 168; experiments of Bessel, 64. + +Pentland, his measurements of the Andes, 28. + +Percy, Dr., on minerals artifically produced. See note by Translator, 268. + +Permian system of Murchison, 277. + +Perouse, La, expedition of, 186. + +Persia, great comet seen in (1608), 139, 140. + +Pertz on the large aerolite that fell in the bed of the River Narni, 116. + +Peters, Dr., velocity of stones projected from Aetna, 122. + +Peucati, Count Mazari, partial infection of calcareous beds by the contact +of syenitic granite in the Tyrol, 262. + +Phillips on the temperature of a coalmine at increasing depths, 174. + +Philolaus, his astronomical studies, 65; his fragmentary writings, 68-71. + +Philosophy of nature, first germ, 37. + +Phosphorescence of the sea in the torrid zones, 202. + +Physics, their limits, 50; influence of physical science on the wealth and +prosperity of nations, 53; province of physical science, 59; distinction +betweeen the physical 'history' and physical 'description' of the world, 71, +72; physical science, characteristics of its modern progress, 81. + +Pindar, 227. + +Plans, geodesic experiments in Lombardy, 168. + +Planets, 89-99; present number discovered, 90. (See note by Translator on +the most recent discoveries, 90, 91); Sir Isaac Newton on their composition, +132; limited physical knowledge of, 156, 157; Ceres, 64-92; Earth, 88-99; +Juno, 64, 92-97, 106; Jupiter, 64, 87, 92-98, 202; Mars, 87, 91-94, 132; +Mercury, 87, 92-94; Pallas, 64, 92; Saturn, 87, 92-94; Venus, 91-94, 202; +Uranus, 90-94; planets which have the largest number of moons, 95, 96. + +Plants, geographical distribution of, 346-350. + +Plato on the heavenly bodies, etc., 69; interpretation of nature, 163; his +geognostic views on hot springs, and volcanic igneous streams, 237, 238. + +Pliny the elder, his Natural History, 73; on comets, 104; aerolites, 122, +123, 130; magnetism, 180; attraction of amber, 188; on earthquakes, 205, +207; on the flame of inflammable gas, in the district of Phasells, 223; +rarity of jasper, 261; on the configuration of Africa, 292. + +Pliny the younger, his description of the great eruption of Mount Vesuvius, +and the phenomenon of volcanic ashes, 235. + +Plutarch, truth of his conjecture that falling stars are celestial bodies, +133, 134. + +Poisson on the planet Jupiter, 64; conjecture on the spontaneous ignition of +meteoric stones, 118; zodiacal light, 141; theory on the earth's +temperature, 172, 173, 174, 176, 177. + +Polarization, chromatic, results of its discovery, 52; experiments on the +light of comets, 105, 106. + +Polybius, 291. + +Posidonius on the Ligyran field of stones, 115, 116. + +Pouilet on the actual source of atmospheric electricity, 335. + +Prejudices against science, how originated, 38; against the study of the +exact sciences, why fallacious, 40-52. + +Prichard, his physical history of Mankind, 352. + +Pseudo-Plato, 54. + +Psychrometer, 332, 338. + +Pythagoras, first employed the word Cosmos in its modern sense, 69. + +Pythagoreans, their study of the heavenly bodies, 65; doctrine on comets, +103. + +Quarterly Review, article on Terrestrial Magnetism, 192. + +Quetelet on aerolites, 114; their periodic return in August, 125. + +Races, human, their geographical distribution, and unity, 351, 359. + +Rain drops, temperature of, 220; mean annual quantity in the two +hemispheres, 333, 334. + +Reich, mean density of the earth, as ascertained by the torsion balance, +170; temperature of the mines in Saxony, 174. + +Reisch, Gregory, his "Margarita Philosophica," 58. + +Remusat, Abel, Mongolian tradition on the fall of an aerolite, 116; active +volcanoes in Central Asia, at great distances from the sea, 245. + +Richardson, magnetic phenomena attending the Aurora, 197; whether +accompanied by sound 200; influence on the magnetic needle of the Aurora, +201. + +Riohamba, earthquake at, 204, 205, 208, 213, 214. + +Ritter, Carl, on his "Geography in relation to Nature and the History of +Man," 48, 67. + +Robert, Eugene, on the ancient sea-line on the coast of Spitzbergen, 296. + +Robertson on the permanency of the compass in Jamaica, 181. + +Rocks, their nature and configuration, 228; geognostical classification into +four groups, 248-251; i. rocks of eruption, 248, 251-253; ii. sedimentary +rocks, 248, 254, 255; iii. transformed, or metamorphic rocks, 248, 259, 255, +256-269; iv. conglomerates, or rocks of detritus, 269, 270; their changes +from the action of heat, 258, 259; phenomena of contact, 258-269; effects of +pressure and the rapidity of cooling, 258, 267. + +Rose, Gustav, on the chemical elements, etc., of various aerolites, 131; on +the structural relations of volcanic rocks, 254; on crystals of feldspar and +albite found in granite, 251; relations of position in which granite occurs, +252-269; chemical process in the formation of various minerals, 265-269. + +Ross, Sir James, his soundings with 27,000 feet of line, 160; magnetic +observations at the South Pole, 187; important results of the Antarctic +magnetic expedition in 1839, 192; rarity of electric explosions in high +northern regions, 337. + +Rossell, M. de, his magnetic oscillation experiments, and their date of +publication, 186, 187. + +Rothmann, confounded the setting zodiscal light with the cessation of +twilight, 143. + +Rozier, observation of a steady luminous appearance in the clouds, 202. + +Rumker, Encke's comet, 106. + +Ruppell denies the existence of active volcanoes in Kordofan, 245. + +Sabine, Edward, observations on days of unusual magnetic disturbances, 178; +recent magnetic observations, 184, 185, 187, 188. + +Sagra, Ramon de la, observations on the mean annual quantity of rain in the +Havana, 333. + +Saint Pierre, Bernardin de, Paul and Virginia, 26; Studies of Nature, 347. + +Salses or mud volcanoes, 224-228; striking phenomena attending their origin, +224, 225. + +Salt works, depth of 158, 159; temperature, 174. + +Santorino, the most important of the islands of eruption, 241, 242; +description of. See note by Translator, 241. + +Sargasso Sea, its situation, 308. + +Satellites revolving round the primary planets, their diameter, distance, +rotation, etc., 94, 99; Saturn's 96-98, 127' Earth's see Moon, Jupiter's, +96, 97; Uranus, 96-98. + +Saurians, flying, fossil remains of, 274, 275. + +Saussure, measurements of the marginal ledge of the crater of Mount +Vesuvius, 232; traces of ammoniacal vapors in the atmosphere, 311; +hygrometric measurements with Humboldt, 334-336. + +Schayer, microscopic organisms in the ocean, 342, 343. + +Scheerer on the identity of eleolite and nepheline, 253. + +Schelling on nature, 55; quotation from his Giordino Bruino, 77. + +Scheuchzner's fossil salamander, conjectured to be an antediluvian man, 274. + +Schiller, quotation from, 36. + +Schnurrer on the obscuration of the sun's disk, 133. + +Schouten, Cornelius, in 1616 found the declination null in the Pacific, 182. + +Schouw, distribution of the quantity of rain in Central Europe, 333. + +Schrieber on the fragmentary character of meteoric stones, 117. + +Scientific researches, their frequent result, 50; scientific knowledge a +requirement of the present age, 53, 54; scientific terms, their vagueness +and misapplication, 58, 68. + +Scina, Abbate, earthquakes unconnected with the state of the weather, 206, +207. + +Scoresby, rarity of electric explosions in high northern regions, 337. + +Sea. See Ocean. + +Seismometer, the, 205. + +Seleucus of Erythrea, his astronomical studies, 65. + +Seneca, noticed the direction of the tails of comets, 102; his views on the +nature and paths of comets, 103, 104; omens drawn from their sudden +appearance, 111; the germs of later observations on earthquakes found in his +writings, 207; problematical extinction and sinking of Mount Aetna, 227, 240. + +Shoals, atmospheric indications of their vicinity, 309. + +Sidereal systems, 89, 90. + +Siljerstrom, his observations on the Aurora, with Lottin and Bravais, on the +coast of Lapland, 195. + +Sirowatskoi, "Wood Hills" in New Siberia, 281. + +Snow-line of the Himalayas, 30-33, 331, 334; of the Andes, 330; redness of +long-fallen snow, 344. + +Solar system, general description, 90-154; its position in space, 89; its +transistory motion, 145-150. + +Solinus on mud volcanoes, 225. + +Sommering on the fossil remains of the large vertebrata, 274. + +Somerville, Mrs., on the volume of fire-balls and shooting stars, 116; +faintness of light of planetary nebulae, 141. + +Southern celestial hemisphere, its picturesque beauty, 85, 86. + +Spontaneous generation, 345, 346. + +Springs, hot and cold, 219-225; intermittent, 219; causes of their +temperature, 220-222; thermal, 222, 345; deepest Artesian wells the warmest, +observed by Arago, 223; salses, 224-226; influence of earthquake shocks on +hot springs, 210, 222-224. + +Stars, general account of, 85-90; fixed 89, 90, 104; double and multiple, +89, 147; nebulous, 85, 86, 151, 152; their translatory motion, 147-150; +parallaxes and distances, 147-149; computations of Bessel and Herschel on +their diameter and volume, 148; immense number in the Milky Way, 150, 151; +star dust, 85; star gaugings, 150; starless spaces, 150, 152; telescopic +stars, 152; velocity of the propagation of light of, 153, 154; apparition of +new stars, 153. + +Storms, magnetic and volcanic. See Magnetism, Volcanoes. + +Strabo, observed the cessation of shocks of erthquake on the eruption of +lava, 215; on the mode in which islands are formed, 227; description of the +Hill of Methone, 240; volcanic theory, 243; divined the existence of a +continent in the northern hemisphere between Theria and Thine, 289; extolled +the varied form of our small continent as favorable to the moral and +intellectual development of its people, 291, 292. + +Struve, Otho, on the proper motion of the solar system, 146; investigations +on the propagation of light, 153; parallaxes and distances of fixed stars, +153; observations on Halley's comet, 105. + +Studer, Professor, on mineral metamorphism. See note by Translator, 248. + +Sun, magnitude of its volume compared with that of the fixed stars, 136; +obscuration of its disk, 132; rotation round the center of gravity of the +whole solar system, 145; velocity of its translatory motion, 145; narrow +limitations of its atmosphere as compared with the nucleus of other nebulous +stars, 141; "sun stones" of the ancients, 122; views of the Greek +philosophers on the sun, 122. + +Symond, Lieut., his trigonometrical survey of the Dead Sea, 296, 297. + +Tacitus, distinguished local climatic relations from those of race, 352. + +Temperature of the globe, see Earth and Ocean; remarkable uniformity over +the same spaces of the surface of the ocean, 303; zones at which occur the +maxima of the oceanic temperature, 319; causes which lower the temperature, +319, 320; temperature of various places, annual, and in the different +seasons, 322, 323-328; thermic scale of temperature, 324, 325; of +continental climates as compared with insular and littoral climates, 321, +322; law of decrease with increase of elevation, 327; depression of, by +shoals, 309; refrigeration of the lower strata of the ocean, 303. + +Teneriffe, Peak of its striking scenery, 26. + +Theodectes of Phaselis on the color of the Ethiopians, 353. + +Theon of Alexandria described comets as "wandering light clouds," 100. + +Theophylactus described Scythia as free from earthquakes, 204. + +Thermal scales of cultivated plants, 324, 325. + +Thermal springs, their temperature, constancy, and change, 221-224; animal +and vegetable life in, 345. + +Thermometer, 338. + +Thibet, habitability of its elevated plateaux, 331, 332. + +Thienemann on the Aurora, 197, 200. + +Thought, results of its free action, 53, 54; union with language, 56. + +Tiberias, Sea of, its depression below the level of the Mediterranean, 296. + +Tides of the ocean, their phenomena, 305, 306. + +Tillard, Capt., on the sudden appearance of the island of Sabrina, 242. + +Tournefort, zones of vegetation on Mount Ararat, 347. + +Tralles, his notice of the negative electricity of the air near high +waterfalls, 336. + +Translator, notes by, 29; on the increase of the earth's internal heat with +increase of depth, 45; silicious infusoria and animalculites, 46; chemical +analysis of an aerolite, 64; on the recent discoveries of planets, 90, 91; +observed the comet of 1843, at New Bedford, Massachusetts, in bright +sunshine, 101; on meteoric stones, 111; on a MS., said to be in the library +of Christ's College, Cambridge, 124; on the term "salses," 161; on +Holberg's satire, "Travels in the World under Ground," 171; on the Aurora +Borealis of Oct. 24, 1847, 194, 195, 199; on the electricity of the +atmosphere during the Aurora, 200; on volcanic phenomena, 203, 204; +description of the seismometer, 205; on the great earthquake of Lisbon, 210; +impression made on the natives and foreigners by earthquakes in Peru, 215; +earthquakes at Lima, 216, 217; on the gaseous compounds of sulphur, 217, +218; on the Lake of Lasch, its craters, 218; on the emissions of inflammable +gas in the district of Phasells, 233; on true volcanoes as distinguished +from salses, 224; on the volcano of Pichincha, 228; on the hornitos de +Jorullo, as seen by Humboldt, 230; general rule on the dimensions of +craters, 230; on the ejection of fish from the volcano of Imbaburn, 223; on +the little isle of Volcano, 234; volcanic steam of Pantellaria, 235; on +Daubeney's work "On Volcanoes," 236; account of the island of Santorino, +241; on the vicinity of extinct volcanoes to the sea, 244; meaning of the +Chinese term "li," 245; on mineral metamorphism, 248; on fossil human +remains found in Guadaloupe, 250; on minerals artifically produced 267, 268; +fossil organic structures, 271, 272; on Coprolites, 271; geognostic +distribution of fossils, 276; fossil fauna of the Sewalik Hills, 278; +thickness of coal measures, 281; on the amber pine forests of the Baltic, +283, 284; elevation of mountain chains, 286, 287; the dinornis of Owen, 287; +depth of the atmosphere, 302; richness of organic life in the ocean, 309; on +filaments of plants resembling the spermatozoa of animals, 341; on the +Diatomaceae in the South Arctic Ocean, 343; on the distribution of the +floras and faunas of the British Isles, 348, 349; on the origin and +diffusion of the British flora, 353, 354. + +Translatory motion of the solar system, 145-150. + +Trogus, Pompeius, on the supposed necessity that volcanoes were dependent on +their vicinity to the sea for their continuance, 243, 244; views of the +ancients on spontaneous generation, 346. + +Tropical latitudes, their advantages for the contemplation of nature, 33; +powerful impressions from their organic richness and fertility, 34; +facilities they present for a knowledge of the laws of nature 35; +transparency of the atmosphere, 114; phosphorescence of the sea, 202. + +Tschudi, Dr., extract from his "Travels in Peru." See Translator's note, +215, 216, 217. + +Turner, note on Sir Isaac Newton, 132. + +Universality of animated life, 342, 343. + +Valz on the comet of 1618, 106. + +Varenius, Bernhard, his excellent general and comparative Geography, 66, 67; +edited by Newton, 66. + +Vegetable world, as viewed with microscopic powers of vision, 341; its +predominance over animal life, 343. + +Vegetation, its varied distribution on the earth's surface, 29-31, 62; +richness and fertility in the tropics, 33-35; zones of vegetation on the +declivities of mountains, 29-32, 346-350. See Aetna, Cordilleras, +Himalayas, Mountains. + +Vico, satellites of Saturn, 96. + +Vigne, measurement of Ladak, 322. + +Vine, thermal scale of its cultivation, 324. + +Volcanoes, 28, 30, 35, 159, 161, 214, 215, 224-248; author's application of +the term volcanic, 45; active volcanoes, safety-valves for their immediate +neighborhood, 214; volcanic eruptions, 161, 210-270; mud volcanoes or +salses, 224-228; traces of volcanic action on the surface of the earth and +moon, 228; influence of relations of height on the occurrence of eruptions, +228-233; volcanic storm, 233; volcanic ashes, 233; classification of +volcanoes into central and linear, 238; theory of the necessity of their +proximity to the sea, 243-246; geographical distribution of still active +volcanoes, 245-247; metamorphic action on rocks, 247-249. + +Vrolik, his anatomical investigations on the form of the pelvis, 352, 353. + +Wagner, Rudolph, notes on the races of Africa, 352. + +Walter on the decrease of volcanic activity, 215. + +Wartmann, meteors, 113, 114. + +Weber, his anatomical investigations on the form of the pelvis, 353. + +Webster, Dr. (of Harvard College, U.S.), account of the island named +Sabrina. See note by Translator, 242. + +Winds, 315-321; monsoons, 316, 317; trade winds, 32-, 321; law of rotation, +importance of its knowledge, 315-317. + +Wine on the temperature required for its cultivation, 324; thermic table of +mean annual heat, 325. + +Wolleston on the limitation of the atmosphere, 302. + +Wrangel, Admiral, on the brilliancy of the Aurora Borealis, coincident with +the fall of shooting stars, 126, 127; observations of the Aurora, 197, 200; +wood hills of the Siberian Polar Sea, 281. + +Xenophanes of Colophon, described comets as wandering light clouds, 100; +marine fossils found in marble quarries, 263. + +Young, Thomas, earliest observer of the influence different kinds of rocks +exercise on the vibrations of the pendulum, 168. + +Yul-sung, described by Chinese writers as "the realm of pleasure," 332. + +Zimmerman, Carl, hypsometrical remarks on the elevation of the Himalayas, 32. + +Zodiacal light, conjectures on, 86-92; general account of, 137-144; +beautiful appearance, 137, 138; first described in Childrey's Britannia +Baconica, 138; probable causes, 141; intensity in tropical climates, 142. + +Zones, of vegetation, on the declivities of mountains, 29-33; of latitude, +their diversified vegetation, 62; of the southern heavens, their +magnificence, 85, 86; polar, 197, 198. + +END OF VOL. 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