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diff --git a/old/60277-0.txt b/old/60277-0.txt deleted file mode 100644 index fddf04c..0000000 --- a/old/60277-0.txt +++ /dev/null @@ -1,15544 +0,0 @@ -The Project Gutenberg EBook of Aërial Navigation, by Albert Francis Zahm - -This eBook is for the use of anyone anywhere in the United States and most -other parts of the world at no cost and with almost no restrictions -whatsoever. 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. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - -Title: Aërial Navigation - A Popular Treatise on the Growth of Air Craft and on - Aëronautical Meteorology - -Author: Albert Francis Zahm - -Release Date: September 13, 2019 [EBook #60277] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK AËRIAL NAVIGATION *** - - - - -Produced by ellinora, Robert Tonsing, and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive/American Libraries.) - - - - - - - - - - AËRIAL NAVIGATION - - A POPULAR TREATISE - ON THE GROWTH OF AIR CRAFT AND - ON AËRONAUTICAL METEOROLOGY - - BY - - ALBERT FRANCIS ZAHM, A.M., M.E., PH.D. - - SECRETARY OF THE AËRO CLUB OF WASHINGTON; GOVERNOR OF THE AËRO - CLUB OF AMERICA; GENERAL SECRETARY OF THE INTERNATIONAL CONFERENCES - ON AËRIAL NAVIGATION IN 1893 AND 1907; OFFICIAL - AMERICAN DELEGATE TO THE AËRONAUTIC CONGRESS OF 1900; - FORMERLY LECTURER ON MECHANICS IN THE UNITED - STATES BUREAU OF STANDARDS, AND PROFESSOR - OF MECHANICS IN THE CATHOLIC UNIVERSITY - OF AMERICA - - [Illustration] - - NEW YORK AND LONDON - D. APPLETON AND COMPANY - 1911 - - COPYRIGHT, 1911, BY - D. APPLETON AND COMPANY - - _Published September, 1911_ - - Printed in the United States of America - - - - - PREFACE - - -The purpose of this work is to portray in popular terms the -substantial progress of aëronautics from its earliest beginning to -the present time. Beyond the introductory account, little note is -taken of experiments, however picturesque or clever, which constitute -no advance in the art, or lead to no useful result. At times some -minutiæ are presented to complete the story of an important series of -achievements; but the unproductive efforts of impractical zealots, -however prominent or widely known in their day, receive scant, if any, -attention. Failures and tragedies where introduced, are described for -the lessons involved rather than for any curious interest investing -them. The griefs and grotesque follies of aëronautic imbeciles form a -long story, but a futile and unprofitable one, of slight concern in the -evolutionary history of a veritable science. - -A general history of aërial locomotion would naturally be divided -into four parts, treating respectively of passive balloons, power -balloons, passive flyers, and power flyers; but in this work a separate -treatment has not been allotted to passive flyers because of their too -backward state of development. Passive gliders which maneuver in the -air merely by virtue of gravitational force, or acquired momentum, are -familiar enough; but the much more interesting passive flyers of human -construction, adapted to rise without motive power considerably beyond -their initial level, or to soar far aloft, and sail long distances by -virtue of favorable winds, are still in their infancy. It may be hoped, -however, that the vulture’s art which now is well nigh overlooked, -because of the triumphant advance of dynamic flight, will soon receive -such attention that future treatises may relate human achievements -in soaring that shall rival the dexterous and marvelous feats of -the condor and albatross, even as the majestic sweep of the dynamic -aëroplane now rivals the powerful rowing flight of the strongest birds -of prey. - -Following the story of the evolution of air ships, a brief account -of the medium they navigate has been added. In particular, the -circumstances which affect the density and motion of the air have been -studied; for the density of the air determines the static lift of air -ships; the density and speed of impact of the air together determine -the dynamic lift and the resistance to progression; while the velocity -of the air current conditions the possible speed of travel in any -direction. It is important, therefore, that the aëronautical student -should have some acquaintance with the general properties of the air -which affect its density, and some knowledge of the generation and -prevalence both of the great currents of the atmosphere, and of the -local winds and invisible turmoils which so nearly concern the safety -and effective progress of the aërial navigator. - -The French units of measurement have been freely used, as well as the -English. This seems advisable because the official rules and records -of international aëronautic events are partly expressed in the metric -system. Moreover, the navigation of a universal medium seems to call -for such universal standards. Indeed a peculiar mission of world travel -is to eliminate provincialism, and to promote universalism of thought, -of sentiment, and of custom. - -In order to lighten the book for the popular reader, some interesting -historical facts and much important quantitative data are placed in the -Appendices, where they may be available to the technical or special -student. - -It is a pleasant duty to acknowledge here my obligations to the U. -S. Signal Corps, the Smithsonian Institution, and the U. S. Weather -Bureau, for much assistance in collecting the materials for this work. -Dr. W. J. Humphreys, of the U. S. Weather Bureau, has very kindly read -the manuscript for the chapters on the atmosphere. - -My thanks are due also to the _Scientific American_ and to -_Aëronautics_ for the use of photographs for the illustrations, as also -to the manufacturers of various aircraft, and to Mr. W. J. Hammer, Mr. -Carl Dientsbach, and Mr. A. S. Levino. - - A. F. ZAHM. - - COSMOS CLUB - WASHINGTON, D. C., - January, 1911. - - - - - CONTENTS - - - CHAPTER PAGE - INTRODUCTION - - INTRODUCTION 3 - - - PART I - - GROWTH OF AËROSTATION - - I.—EARLY HISTORY OF PASSIVE BALLOONS 29 - - II.—PRACTICAL DEVELOPMENT OF PASSIVE BALLOONS 54 - - III.—EARLY HISTORY OF POWER BALLOONS 78 - - IV.—INTRODUCTION OF GASOLINE-DRIVEN DIRIGIBLES 101 - - V.—PRACTICAL DEVELOPMENT OF NON-RIGID DIRIGIBLES 115 - - VI.—DEVELOPMENT OF RIGID DIRIGIBLES 145 - - - PART II - - GROWTH OF AVIATION - - VII.—MODEL FLYING MACHINES 173 - - VIII.—NINETEENTH CENTURY MAN-FLYERS 202 - - IX.—AËROPLANES OF ADEQUATE STABILITY AND POWER 235 - - X.—ADVENT OF PUBLIC FLYING 256 - - XI.—STRENUOUS COMPETITIVE FLYING 283 - - XII.—FORCING THE ART 307 - - - PART III - - AËRONAUTIC METEOROLOGY - - XIII.—GENERAL PROPERTIES OF FREE AIR 347 - - XIV.—GENERAL DISTRIBUTION OF HEAT AND PRESSURE 363 - - XV.—PERMANENT AND PERIODIC WINDS 376 - - XVI.—CYCLONES, TORNADOES, WATERSPOUTS 394 - - XVII.—THUNDERSTORMS, WIND GUSTS 422 - - - APPENDICES - - I.—STRESS IN A VACUUM BALLOON 443 - - II.—AËRONAUTIC LETTERS OF BENJAMIN FRANKLIN 446 - - III.—SUCCESSFUL MILITARY DIRIGIBLE BALLOONS 456 - - IV.—THE RELATIONS OF WEIGHT, SPEED, AND POWER OF FLYERS 478 - - V.—CURTISS’ HYDRO-AËROPLANE EXPERIMENTS 481 - - INDEX 487 - - - - - LIST OF PLATES - - - FACING - PAGE - - PLATE I 66 - Glaisher and Coxwell. - Parseval Kite Balloon. - - PLATE II 98 - Haenlein’s Gas-driven Dirigible. - Wölfert’s Benzine-driven Dirigible. - Santos-Dumont’s Dirigible, _No. 16_. - - PLATE III 116 - The _Lebaudy_. - _La Patrie._ - Lebaudy’s _Morning Post_. - - PLATE IV 124 - _La Ville de Paris._ - _Colonel Renard._ - - PLATE V 128 - _Zodiac III._ - _Zodiac IV._ - - PLATE VI 130 - _La Belgique._ - Italian Military Dirigible _No. I bis_. - - PLATE VII 132 - _Clément-Bayard I._ - _Clément-Bayard II._ - - PLATE VIII 138 - _U. S. Signal Corps Dirigible I._ - _Gross II._ - - PLATE IX 140 - _Parseval I._ - _Parseval II._ - - PLATE X 146 - _Gross III._ - Zeppelin Airship Structure. - - PLATE XI 160 - Zeppelin Dirigible Resting on the Water. - Zeppelin Dirigible over Zürich. - - PLATE XII 182 - Henson’s Aëroplane. - Ader’s Aëroplane. - - PLATE XIII 186 - Stringfellow’s Aëroplane (Front). - Stringfellow’s Aëroplane (Side). - - PLATE XIV 192 - Phillips’s Tethered Aëroplane. - Phillips’s Aëroplane. - - PLATE XV 194 - Langley’s Steam Model. - Langley’s Gasoline Model. - Langley’s Two Surface Gasoline Model. - - PLATE XVI 212 - Lilienthal’s Monoplane Glider. - Lilienthal’s Biplane Glider. - Pilcher’s Monoplane Glider. - - PLATE XVII 218 - Chanute’s Five-Deck Glider. - Herring in Chanute Biplane. - Herring’s Compressed-air Biplane. - - PLATE XVIII 226 - Maxim’s Aëroplane. - Langley’s Large Aëroplane. - - PLATE XIX 246 - First Wright Glider. - Second Wright Glider. - - PLATE XX 248 - First Wright Aëroplane (Rear). - First Wright Aëroplane (Side). - - PLATE XXI 252 - Montgomery’s Aëroplane. - - PLATE XXII 258 - Santos-Dumont’s Biplane. - Santos-Dumont’s _Demoiselle_. - - PLATE XXIII 260 - Farman Biplane, 1908. - Farman Biplane, 1909. - Harmon in Farman Biplane. - - PLATE XXIV 264 - The _Red Wing_. - Curtiss Biplane. - Curtiss Biplane with Pontoons. - - PLATE XXV 268 - Blériot Flying Over Toury-Artenay Circuit. - Blériot Monoplane _No. VIII_. - Blériot Monoplane _No. IX_. - - PLATE XXVI 272 - Wright Biplane of 1908. - Standard Wright Biplane of 1910. - Wright Racing Biplane of 1910. - - PLATE XXVII 286 - _Blériot XI_ With Moisant Aviator on Mexican Border. - _Blériot XII._ - - PLATE XXVIII 288 - _Antoinette_ Monoplane of 1909. - _Antoinette_ Monoplane of 1910. - - PLATE XXIX 302 - Esnault-Pélterie Monoplane, Early Pattern. - Esnault-Pélterie Monoplane of 1910. - - PLATE XXX 304 - Grade Monoplane. - Cody Biplane. - - PLATE XXXI 332 - Fabre Hydro-aëroplane. - Paulhan Hydro-aëroplane. - Moisant Metal Monoplane. - - PLATE XXXII 482 - Curtiss Starting from the Water. - Curtiss Biplane for Land and Water. - Curtiss Triplane Risen from the Water. - - - - - LIST OF ILLUSTRATIONS IN TEXT - - - FIG. PAGE - - 1.—Da Vinci’s designs for human flying-gear 9 - - 2.—A possible air-scout 12 - - 3.—Blanchard’s flying-machine 17 - - 4.—Lana’s proposed vacuum balloon 24 - - 5.—Montgolfier’s experimental balloon 34 - - 6.—Charles’ first hydrogen balloon 36 - - 7.—Montgolfier’s passenger balloon 39 - - 8.—Charles’ passenger balloon 43 - - 9.—La Flesselle 50 - - 10.—_The Great Balloon of Nassau_ 55 - - 11.—Car of Nadar’s balloon 61 - - 12.—Diagram of a modern spherical balloon with ripping panel 75 - - 13.—Blanchard’s dirigible balloon, 1784 80 - - 14.—Robert Brothers’ dirigible, 1784 82 - - 15.—General Meusnier’s proposed dirigible, 1784 85 - - 16.—Rufus Porter’s dirigible, 1820 87 - - 17.—Jullien’s model dirigible, 1850 88 - - 18.—Giffard’s steam dirigible, 1852 89 - - 19.—Dupuy de Lome’s dirigible, 1872 92 - - 20.—Renard’s dirigible, _La France_, 1884 94 - - 21.—_La Ville de Paris_ 121 - - 22.—_Le Petit Journal_, Zodiac type 128 - - 23.—_Clément-Bayard II_, 1910 133 - - 24.—_Morning Post_ dirigible, 1910 135 - - 25.—Route of British military dirigibles from France to England, - 1900 137 - - 26.—Da Vinci’s helicopter 175 - - 27.—Da Vinci’s parachute 176 - - 28.—Veranzio’s parachute 178 - - 29.—Lenormand’s parachute, 1784 179 - - 30.—Paper traveling parachute 181 - - 31.—Wenham’s aëroplane, 1866 185 - - 32.—Penaud’s aëroplane toy, 1871 187 - - 33.—Tatin’s aëroplane model, 1879 188 - - 34.—Hargrave’s model screw monoplane, 1891 190 - - 35.—Hargrave’s kite 191 - - 36.—Launoy and Bienvenu’s helicopter, 1784 198 - - 37.—Forlanini’s helicopter, 1878 200 - - 38.—Le Bris’ aëroplane, 1855 204 - - 39.—Mouillard’s aëroplane 208 - - 40.—Blériot’s Toury-Artenay aëroplane circuit, 1908 269 - - 41.—Map of the “Circuit de l’Est” 330 - - 42.—Diagram of Curtiss hydro-aëroplane 333 - - 43.—The Etrich monoplane of 1910 336 - - 44.—Summer and winter average vertical temperature gradients 369 - - 45.—General circulation of the atmosphere 378 - - 46.—Normal Wind direction and velocity for January and February - (Köppen) 381 - - 47.—Normal Wind direction and velocity for July and August - (Köppen) 383 - - 48.—Trade and counter-trade winds 384 - - 49.—Velocity diagram in horizontal section of a cyclone 398 - - 50.—Funnel-like cloud sometimes observed in a tornado 409 - - 51.—Vertical section of the St. Louis, Mo., tornado of May 27, - 1896 411 - - 52.—Horizontal section of St. Louis tornado of May 27, 1896 412 - - 53.—Vertical section of short tornado 414 - - 54.—Vertical section of a tall tornado 415 - - 55.—Vertical section of a hail tornado 417 - - 56.—Universal anemograph 428 - - 57.—Records of wind variation in horizontal and vertical - direction 429 - - 58.—Records of Wind speed obtained by Langley 433 - - - - - INTRODUCTION - - - - - INTRODUCTION - - FANCY AND FOLK-LORE - - Of silver wings he took a shining pair, - Fringed with gold, unwearied, nimble, swift; - With these he parts the winds, the clouds, the air, - And over seas and earth himself doth lift. - Thus clad he cuts the spheres and circles fair, - And the pure skies with sacred feathers clift; - On Lebanon at first his feet he set - And shook his wings with rosy may-dews wet. - TASSO, CANTO I, XIV. - - -How beautiful! May we hope ever to journey thus, on wings actuated by -human power? It is an old question, once dear to the philosopher and -fool alike, but now important mainly to the fool. Or say more kindly it -is the affair of untechnical inventors—the amateur, the rustic, the man -of chimerical dreams. For the wise aëronaut now numbers that project -among the roseate illusions of his youth.[1] - -Ovid relates a story, doubtless credible in his day, of a clever -craftsman who with his son flew bravely aloft, the very first time they -put on wings. Daedalus, a Greek architect, having fled from Athens for -murder, went with his son Icarus to the island of Crete, where he built -the celebrated labyrinth for Minos, the king. He offended that monarch -and was cast into prison. In order to escape he made wings for himself -and his son, with which they flew far over the sea. But Icarus, in his -elation, soared too near the sun, ruined his wings, fell into the sea -and was drowned. For proof of this we have the Icarian Sea, named after -the unfortunate boy. Also we have Ovid’s charming poem: - - In tedious exile now too long detain’d - Daedalus languish’d for his native land; - The sea foreclosed his flight, yet thus he said; - “Though earth and water in subjection laid, - O cruel Minos, thy dominion be, - We’ll go through air; for sure the air is free.” - Then to new arts his cunning thought applies, - And to improve the work of nature tries. - A row of quills, in gradual order placed, - Rise by degrees in length from first to last; - As on a cliff the ascending thicket grows; - Or different reeds the rural pipe compose: - Along the middle runs a twine of flax, - The bottom stems are join’d by plaint wax; - Thus, well compact, a hollow bending brings - The fine composure into real wings. - His boy, young Icarus, that near him stood, - Unthinking of his fate, with smiles pursued - The floating feathers, which the moving air - Bore loosely from the ground, and wafted here and there: - Or with the wax impertinently play’d, - And with his childish tricks the great design delay’d. - The final masterstroke at last imposed, - And now, the great machine completely closed; - Fitting his pinions on, a flight he tries, - And hung self-balanced in the beaten skies. - Then thus instructs his child: “My boy, take care - To wing your course along the middle air: - If low, the surges wet your flagging plumes; - If high, the sun the melting wax consumes. - Steer between both: nor to the northern skies, - Nor South Orion, turn your giddy eyes, - But follow me; let me before you lay - Rules for the flight, and mark the pathless way.” - Thus teaching, with a fond concern, his son, - He took the untried wings, and fix’d them on: - But fix’d with trembling hands; and, as he speaks, - The tears roll gently down his aged cheeks; - Then kiss’d, and in his arms embraced him fast, - But knew not this embrace must be the last; - And mounting upward, as he wings his flight, - Back on his charge he turns his aching sight; - As parent birds, when first their callow care - Leave the high nest to tempt the liquid air; - Then cheers him on, and oft, with fatal art, - Reminds the stripling to perform his part. - These, as the angler at the silent brook, - Or mountain shepherd leaning on his crook, - Or gaping ploughman, from the vale descries, - They stare, and view them with religious eyes, - And straight conclude them gods; since none but they - Through their own azure skies could find a way. - Now Delos, Paros, on the left are seen, - And Samos, favour’d by Jove’s haughty queen; - Upon the right, the isle Lebynthos named, - And fair Calymne for its honey famed. - When now the boy, whose childish thoughts aspire - To loftier aims, and make him ramble higher, - Grown wild and wanton, more embolden’d flies - Far from his guide, and scars among the skies: - The softening wax, that felt a nearer sun, - Dissolved apace, and soon began to run: - The youth in vain his melting pinion shakes, - His feathers gone, no longer air he takes: - “Oh! father, father!” as he strove to cry, - Down to the sea he tumbled from on high, - And found his fate; yet still subsists by Fame, - Among those waters that retain his name. - The Father, now no more a father, cries: - “Ho, Icarus! where are you?” as he flies; - “Where shall I seek my boy?” he cries again, - And saw his feathers scatter’d on the main; - Then cursed his art; and funeral rites conferr’d - Naming the country from the youth interr’d. - -How tender and apprehensive that gentleman’s farewell, compared with -the modern vogue in like circumstances! Of the two Americans at Berlin -who fell four thousand feet in a balloon, it is not recorded that they -either kissed or wept.[2] But some Teutonic Ovid may yet adorn the tale -with quaint embellishments. - -Taking more serious note of Daedalus, it will be observed that he -has had few imitators. It is because he never really flew, and no -one else can fly, in such manner. That is to say, no man can achieve -practical flight on wings actuated by his own muscular power. It may be -physically possible for an athlete putting forth herculean energy for -a few seconds to sustain himself on wings of enormous spread; but in -every lightest zephyr he would be as helpless as a thistle seed. - -The actual area of wing required for a man of given weight and power -may be roughly estimated; at least its lower limit of size can be -determined. Lord Rayleigh,[3] on purely theoretical ground, has -computed that a man operating a screw propeller 280 feet in diameter, -moving without frictional loss, could sustain his weight for a period -of eight hours a day at a comfortable rate of work. But that estimate -does not include the weight of the propeller. By exerting ten times his -normal power the man could support his weight with a 28-foot propeller. - -The physical basis of the computation is the same for every type of -flyer, whether bird, man, or machine. Its weight must be sustained by -hurling the air downward. The humming bird in its aërial pause, the bee -floating beside a blossom, rests on a down-driven column of air. The -home-gliding eagle at dusk may encounter a medium in stillest repose, -but he leaves behind him a down-flowing wake, viewless, maybe, but none -the less real. In all cases the downward impulse per second given to -the air must equal the weight supported by its reaction. If the wings -be very extensive a proportionate mass of air may be struck down, and -yield support with so much the less exertion. - -Horizontal flight promises little more than direct screw lift, with the -feeble energy of the human muscle. The best modern aëroplanes carry -less than 100 pounds per horse power, while an average man must weigh, -with a light machine, not less than 200 pounds, and must therefore -exert upwards of two horse power during flight. Such an output of -energy would exhaust a powerful athlete in a few seconds. Hence from -every point of view it appears that Daedalean flight, which still has -its devotees in some form, was and always will be utterly impracticable. - -Ruskin finds another objection to the disciples of the winged arm. -In his disquisition on the equilibrium of angels he complains that -those of the traditional two-wing type are devoid of gravitational -balance. Such creatures vex the imagination with apprehensions for -their stability; hence they cannot be entirely beautiful. The centroid -of an angel is in the small of its back, whereas the center of wing -support is well forward; therefore the horizontal poise is absurd and -unæsthetic. The scientific artist, consequently, views with pain the -picture of a fair lady floating level through space supported only at -her front end. - -Milton adroitly forestalls this censure. In the conception of his -glorious Raphael, he provides consummately for uniform and adequate -support: - - Six wings he wore, to shade - His lineaments divine; the pair that clad - Each shoulder broad, came mantling o’er his breast - With regal ornament; the middle pair - Girt like a starry zone his waist, and round - Skirted his loins and thighs with downy gold, - And colors dipped in Heaven; the third his feet - Shadowed from either heel with feathered mail, - Sky-tinctured grain. Like Maia’s son he stood, - And shook his plumes, that heavenly fragrance filled - The circuit wide. - -Leonardo da Vinci, who was a gifted engineer as well as an artist, -devised a flying gear for man which shows some dynamic improvement over -the mechanism of the old-time angels, flying gods, and hobgoblins. As -shown in the accompanying sketch, it provided for gravitational balance -by use of an expanding tail projecting well to the rear. Moreover, the -propulsion was to employ both arms and legs. This design is considered -very remarkable for the time in which it was produced, probably a few -years before the discovery of America; and yet it is but one of Da -Vinci’s quaint aëronautical inventions, as will appear later. - -A less futile scheme of aviation may be to saddle the birds. If one -eagle can float a child, a few may possibly carry a man. They are -physically able; they are inexpensive; they are unwearied, nimble, -swift. Some harness, some tuition may be required; but these come -to the industrious. Apparently, such locomotion is a sport worth -developing; a royal art, if you please; for who would not course the -sky in a purple palanquin borne by imperial eagles? - -Kai Kaoos, the King of Persia, is credited with a voyage of this kind, -as described in the _Shah-Nemeh_, or _King-Book_, written in the tenth -century: - - “To the king it became a matter of great concern how he might - be enabled to ascend the heavens, without wings; and for that - purpose he consulted the astrologers, who presently suggested a - way in which his desires might be successfully accomplished. - -[Illustration: FIG. 1.—DA VINCI’S DESIGNS FOR HUMAN FLYING-GEAR.] - - “They contrived to rob an eagle’s nest of its young, which they - reared with great care, supplying them with invigorating food. - - “A frame of aloes-wood was then prepared, and at each of the - four corners was fixed perpendicularly a javelin surmounted - on the point with the flesh of a goat. At each corner again - one of the eagles was bound, and in the middle the king was - seated with a goblet of wine before him. As soon as the eagles - became hungry they endeavored to get at the goat’s flesh upon - the javelins, and by flapping their wings, and flying upwards - they quickly raised the throne from the ground. Hunger still - pressing on them, and still being distant from their prey, - they ascended higher and higher in the clouds, conveying the - astonished king far beyond his own country. But after a long - and fruitless exertion, their strength failed them, and, unable - to keep their way, the whole fabric came tumbling down from the - sky, and fell upon a dreary solitude in the Kingdom of Chin, - where Kai Kaoos was left a prey to hunger, alone, and in utter - despair.” - -One might prefer a single bird, which could be ridden bareback by a man -or woman of common equestrian skill. The early philosophers, therefore, -sought with some care for such a creature. The following is related by -Bishop Wilkins: - - “Cardan and Scaliger doe unanimously affirm, that there is - a bird amongst the Indians of so great a bignesse, that his - beak is often used to make a sheath or scabbard for a sword. - And Acosta tells us of a fowl in Peru called Condores, which - will of themselves kill and eat up a whole calf at a time. Nor - is there any reason why any other body may not be supported - and carried in the air, though it should as much exceed the - quantity of these fowls as they do the quantity of a flie. - Marcus Polus mentions a fowl in Madagascar which he cals a - Ruck, the feathers of whose wings are 12 paces, or threescore - foot long, which can with as much ease scoop up an elephant as - our kites do a mouse. If this relation was anything credible, - it might serve as an abundant proof for the present quaere.” - -As the roc has proved a myth, one questions whether a saddle bird -may not be evolved by judicious breeding. But opposed to this is the -square-cube law of the Greek geometer, by which a learned geologist -demonstrated that nature has reached the limit of her resources in the -production of large flyers, the ostrich, for example, being too bulky -to navigate at all. As a last resource, then, the human dwarf may -breed his weight downward to accommodate the bird. Assuredly, the most -powerful flyer can carry the lightest human dwarf without difficulty. - -Such aërial cavalry has been projected occasionally, and if fairly -developed might have interesting employment. Its military value, to -say nothing of its civil uses, would be considerable. An aërial scout -that could hide in a tree top, or small cloud, then flit home with full -intelligence of the enemy, would be effective and unique. In aggressive -warfare it would serve the plan of that ingenious Englishman who -proposes to repel a German invasion by dispatching birds to peck holes -in the enemy’s war balloons. But here the dwarf might be omitted, if -the birds were taught to have a definite interest in attacking aërial -cruisers with their beaks, or with steel-armed spurs like those of the -Spanish fighting cock, or with talons treated chemically to strike -fire. Sparrows with sulphur-pointed toes could easily annihilate an -aërial squadron at all combustible. - -Recurring to the geologist, it may be added that, having discovered the -major limit of feathered navigators, he concluded, as a corollary, that -human flight is forever impossible. That was in the latter eighties. -In 1901 a versatile astronomer adduced the same law to prove that an -aëroplane could not be made to carry a man. Presently, learning that -this had been achieved, he proved, in a second mellifluous paper, that -an aëroplane could not carry, several men.[4] Having erred twice, he -wrote a final article announcing that a flyer is fatuous, anyhow, -because she cannot repair her engines in the sky! - -[Illustration: FIG. 2.—A POSSIBLE AIR-SCOUT.] - -Of the numerous daring and industrious inventors who, during remote -generations, have launched themselves in the air on some species of -rigid or vibrant wings, a few were men of considerable equipment in -philosophy, or mechanics, and enjoyed a sufficient measure of success -to deserve passing notice; though it seems that no man before the -middle of the eighteenth century made a permanent contribution to the -real art of mechanical flight, if we except the ingenious suggestive -devices of Leonardo da Vinci. However skilfully their flying apparatus -may have been planned, or operated, the results were lost to the world, -due to inaccurate or inadequate description. Such inventors were J. B. -Dante, in the fifteenth century, and the Marquis de Bacqueville, in the -seventeenth. Each of these made one, or more, considerable flights, if -we may credit the unwavering testimony of their contemporaries; but -neither has left a sketch of his device, nor a school of followers to -continue his spectacular practice. - -Jean-Baptiste Dante, a shrewd observer and profound mathematician, who -flourished toward the end of the fifteenth century, a contemporary of -Da Vinci and Columbus, is reported by the historians of that day to -have sailed successfully through the air on nonvibrant wings designed -by himself after a careful study of the great soaring birds. Perching -above a steep crag on the shore of Lake Trasimene, he set his wings -to the wind at a nice angle, as one sets the sails of a vessel; then, -lifted by the swelling breeze, he rose grandly aloft and floated far -over the waters. Again and again he repeated the experiment, until -the fame thereof secured for him a request to make the demonstration -at the marriage fêtes of the illustrious general, Barthelmi Alviano. -He accepted the invitation, and, starting from the top of the highest -tower in the city of Perugia, he sailed over the public square, -and balanced himself for a long time in space, amid the shouts and -acclamations of the multitude, attracted to Perugia by the novelty of -his performance. But, sad to relate, the very first time he performed -these wonderful maneuvers above the solid ground instead of the lake, -one of the levers used to alter the impact angle of his wings gave way, -disturbing his aërial poise, and causing him to pitch down upon Notre -Dame church, breaking one of his legs. After this he taught mathematics -at Venice, where he died of fever at the age of forty years. - -In 1742, the Marquis de Bacqueville, at the age of sixty-two years, -announced that on a certain day he would fly from his house on the -Seine, traverse the river, and land in the Garden of the Tuileries. A -great multitude assembled, crowding both shores and the two bridges. -At the appointed moment the Marquis appeared with his pinions, and -launched himself from the terrace. He sailed forth in majestic and -serene poise, on graceful wings not unlike those of the traditional -angels. He was gliding directly toward the Tuileries, and he enjoyed a -happy cruise quite to the middle of the river. Then something happened; -his movements became fitful and uncertain; he plunged downward and -broke his leg on a laundry boat. The reason for his stopping there can -only be surmised, for he had nothing to report. He did not quite fulfil -his program, but he flew nine hundred feet delightfully, and he landed -without getting wet. - -Commentators have marveled as to the nature of the mechanism used by -Dante and by De Bacqueville. Historians have strongly attested the -fact of the flights, but have overlooked the means. The inventors must -have employed aërial gliders of some kind, for adequate motive power -was not available before the end of the nineteenth century. Even as -an experiment in gliding, or soaring, the achievement of Dante was -most daring and wonderful, eclipsing the best performances up to the -twentieth century. It is strange that in that period of science the -survivor of such an experience, and a college professor, should not -have left to the world a careful account of such an extraordinary -performance. The alleged flights, however, were unquestionably -feasible, even in that remote period, for the construction of an -aërial glider is a simple task not beyond the capacity of craftsmen -in the fifteenth century A.D., or even the fifteenth century -B.C., directed by a skilful designer. - -Besides the wing-armed scheme of flight credited to Daedalus, and -contemplated by Da Vinci, various other plans were evolved in -succeeding years. Aërial chariots and flying machines were devised for -the more advantageous use of muscular energy. In all these, of course, -the passenger could be both power plant and captain of the ship. - -One of the earliest authenticated devices of this kind was the -invention of Blanchard, described by him in the _Journal de Paris_, -August 28, 1781, nearly two years before the invention of the hot-air -balloon, of which he became later an enthusiastic votary. As his device -is but one of a large number that appeared before the close of the -nineteenth century, and the advent of light motors, the reader who -wishes fuller acquaintance with man-driven airships may be referred -to Mr. Chanute’s book, entitled _Progress in Flying-Machines_, which -describes a large variety of such inventions, and discusses the merit -and weakness of each. - -Blanchard prefaces the description of his machine by answering some -criticisms of his project, apparently ventured by his neighbors. “They -object to me,” he writes, “that flying is not the business of man, but -rather of the feathered birds. I reply that feathers are not at all -necessary to the bird for flight; any fabric suffices. The fly, the -butterfly, the bat, etc., fly without feathers and with fanlike wings -of material resembling horn. It is, then, neither the material nor -the form that causes flight, but the volume and the celerity of the -movement, which should be as lively as possible. - -“They object, moreover, that a man is too heavy to lift himself alone -with wings, much less in a vessel which of itself presents enormous -weight. I reply that my ship is extremely light; as to the man’s -weight, I pray that attention be given to that which M. de Buffon says -in his _Histoire Naturelle_, on the subject of the condor; this bird, -though of enormous weight, easily lifts a two-year-old heifer weighing -at least a hundred pounds, the whole with wings of about thirty to -thirty-six feet expanse.” - -He then describes the vessel as a little ship four feet long by two -feet wide, having on either side two posts, each supporting a wing ten -feet long, the whole forming a parasol twenty feet in diameter. The -construction was illustrated by an engraver, who had seen the vessel -and was convinced of its practicability. In conclusion, the inventor -writes that people shall see him cleave the air with more speed than -the crow, and that without losing his breath, being protected by a -pointed mask of peculiar construction. But, as he failed to make good -his promises, he was subjected to ridicule, as well as praise, by the -local press, one of the caricatures portraying him in the act of making -an ascension before a concourse of bulging-eyed savants and long-eared -jackasses, wearing spectacles to accentuate the appearance of wisdom -and solemnity. - -The scientific coterie of Paris were apparently impatient of the -attention shown Blanchard by the press and people. Accordingly, in May, -1782, the distinguished astronomer, De Laland, of the French Academy, -administered a mild rebuke to the editors of the _Paris Journal_. -“Gentlemen,” he wrote, “you have given so much time to air ships and -divination rods that one might eventually think that you believe in -these follies, or that the scientists who coöperate with your journal -have nothing to say to dispel these absurd pretensions. Permit me, -therefore, gentlemen, to occupy some lines in your journal to assure -your readers that if the savants are silent it is only because of their -contempt. - -[Illustration: FIG. 3.—BLANCHARD’S FLYING-MACHINE.] - -“It has been demonstrated to be impossible for a man in any manner -whatever to raise himself, or even to sustain himself, in the air. M. -Coulomb, of the Academy of Sciences, at one of our meetings a year ago, -read a paper in which he showed clearly, by calculating the power of -a man, determined by experiments, that he would require wings two or -three thousand feet long moved three feet per second; hence no one but -an ignoramus would make an attempt of this kind.” - -Not many months after this lofty deliverance, Blanchard took De Lalande -up in a balloon—“the dead borne by the dumb.” - -Coulomb’s calculation that a man’s pinions should be half a mile long -must have been discouraging to those inventors who believed in him; -for, granting that such wings could lift a man, who could lift the -wings? And at that date the steam engine was only beginning to develop; -the petroleum engine was hardly thought of. No wonder that people -turned eagerly to the balloon when it finally appeared. - -There has been some controversy as to what person first clearly -conceived a feasible design for a balloon. The conception was -certainly not new to the world in 1783, when Joseph Montgolfier made -his classical experiment. Indeed, prior to that date three distinct -principles of aërial flotation had been entertained by natural -philosophers; first, that a boat could be so formed of heavy material -as to ride on the upper surface of the atmosphere, as a metallic vessel -floats on the water; second, that a closed hull, comprising a partial, -or complete, vacuum, could be made light enough to rise; third, that -a bag could be made buoyant by filling it with material lighter than -air. Of course, it is now clear to men versed in mathematics that only -the light-gas principle is mechanically applicable. But the vacuum -principle still has adherents among inventors who are too “practical” -to understand, or trust, exact computation; and the first principle, -though now discarded by everyone, was plausible enough, even to -accomplished scientific men, before the experiments of Torricelli, and -his invention of the barometer, made in 1643. It may, therefore, be -interesting to notice some of the proposed, or reported, air ships -based upon these various principles. The following is from _Mendoza, -Viridario, libri III, probl. 47_: - - “Any brass vessel full of air, which otherwise would sink, is - sustained on the surface of the water, though naturally of - much greater specific gravity; consequently a wooden ship, or - one of any other material, placed on the summit of an aërial - superficies and filled with elementary fire, will be sustained - in that position till the gravity of the vessel becomes greater - than the sustaining power of the fire it contains.” - -This is a clear scientific exposition of a plan for navigating the -atmosphere on its upper surface, assuming a distinct upper surface -to exist. In commenting on this passage, the Jesuit Schottus, in his -_Magia Universalis_, uses an expression which indicates his belief that -a vessel can be made to _float in the air_ by filling it with ether, or -the element of fire. He says: - - “In such terms has this matter been treated by Mendoza (died - 1626); nor is there any improbability involved in his view, - whether the element of fire be placed above the air, or, what - is still more credible, the ether—that is, the purest air. - Although any wood, iron, copper, lead, and such like metals are - weightier than an equal volume of water, and for that reason - will sink in water when placed there alone, yet if fabricated - into hollow shapes, and filled with our impure and heavy air, - they swim upon waters, and are adapted to the construction of - ships, and are sustained by water without danger of immersion; - thus, although these bodies are of greater specific gravity - than our air, nevertheless, when shaped into a boat and filled - with that very light material, they can _float in the air_, - and are suitable material for the construction of small ships, - because the entire work composed of the little ship and the - ether can be made lighter than an equal volume of our impure - air, even in the highest region.” - -As Roger Bacon proposed a similar device in 1542, Mendoza’s was not -entirely new and may not have been original. Bacon, describing his -aërial vessel, says: “It must be a large, hollow globe of copper, or -other suitable metal, wrought extremely thin, in order to have it -as light as possible. It must then be filled with ‘ethereal air or -liquid fire,’ and then be launched from some elevated point into the -atmosphere, where it will float like a vessel on water.” - -In the year 1646 another learned Jesuit published a book, _Ars Magna -Lucis et Umbræ in Mundo_, in which he relates an episode indicating -that one of his order had made use of a hot-air balloon to intimidate -some ignorant pagans. The following demonstration, if reported by a -modern missionary, would be accepted as a matter of course; why, then, -should we gravely question the story, since it describes an achievement -quite possible at the time, assuming that the necessary materials were -available? And even assuming the report to be fictitious, still it is a -scientific description of a practicable hot-air balloon, presented and -credited by a learned scholar and accomplished mathematician more than -a century before the balloon was publicly exhibited by the illustrious -Frenchmen. He writes: - - “I know that many of our fathers have been rescued from the - most imminent dangers amongst the barbarians of India by such - inventions. These were cast into prison, and whilst they - continued ignorant of any means of effecting their liberation, - some one, more cunning than the rest, invented an extraordinary - machine, and then threatened the barbarians, unless they - liberated his companions, that they would behold in a short - time some extraordinary portents, and experience the visible - anger of the Gods. The barbarians laughed at the threat. He - then had constructed a dragon of the most volatile paper, and - in this he enclosed a mixture of sulphur, pitch, wax, and so - artistically prepared all his materials, that, when ignited, it - would illumine the machine, and exhibit the following legend - in their vernacular idiom, _The Anger of God_. The body being - formed and the ingredients prepared, he then affixed a long - tail, and committed the machine to the heavens, and, favored - by the wind, it soared aloft towards the clouds. The spectacle - of the dragon so brilliantly lit was terrific. The barbarians, - beholding the unusual motion of the apparition, were smitten - with the greatest astonishment, and now, remembering the - threatened anger of Deity and the words of the father, they - were in fear of expiating the punishment he had prognosticated - for them. Therefore, without delay, they threw open the gates, - they suffered their prisoners to go forth in peace and enjoy - their freedom. In the meantime the fire seized on the machine - and set it in a blaze, and with an explosion, which was - interpreted as an expiring declaration of satisfaction, it, - apparently of its own accord, vanished from sight, as if it - had accomplished its supernatural mission. Thus the fathers, - through the apprehension which this natural manifestation - inspired, obtained that which could not be purchased with a - large amount of gold.” - -Perhaps the reader will permit another anecdote, not entirely for its -scientific value, but because he may like to compare the attitude of -people toward aërial navigation in the dark ages with the attitude of -his neighbors at the opening of the twentieth century. In two histories -by Jef le Ministre and De Colonia, of the town of Lyons, the following -account is given: - - “Toward the end of Charlemagne’s reign, persons who lived - near Mount Pilate in Switzerland, knowing by what means - pretended sorcerers traveled through the air, resolved to try - the experiment, and compelled some poor people to ascend in an - aërostal. This descended in the town of Lyons, where they were - immediately hurried to prison, and the mob desired their death - as sorcerers. The judges condemned them to be burned; but the - Bishop Agobard suspended the execution, and sent for them to - his palace, that he might question them. They answered: ‘Qu’ils - sont du pays meme, que des personnes de consideration les ont - forcés de se laisser conduire, leur promettent qu’ils verroient - des chose merveilleuses; et qu’ils sont veritablement descendu - par l’air.’ Agobard, though he could not believe this fact, - gave credence to their innocence, and allowed them to escape. - On this occasion he wrote a work on the superstition of the - time, in which he demonstrated the impossibility of rising in - the air; that it is an error to believe in the power of magic; - and that it has its existence in the credulity solely of the - people.” - -One of the first men to make an aërial model like a fire balloon was -the celebrated Brazilian, Bartholomeo-Lourenco de Gusmao, who in his -day was nicknamed the “flying man,” and who is reported to have made -a remarkable experiment in aërial locomotion at Lisbon. The following -account of it is found in a manuscript of Ferreira: - - “Gusmao made his experiment on August 8, 1709, in the court of - the Palace of the Indies, before his majesty and a large and - distinguished audience, with a globe which lifted itself softly - to the height of the hall of the Ambassadors, then descended in - like manner. It was borne up by certain materials which burned - and which the inventor himself had ignited.” - -All the details of this description, which was written a generation -or more before the Montgolfier experiment, suggest at once a hot-air -balloon. But a note printed in 1774 and cited by Cavallo explains that -the globes must have been transported by gas. It is certain that early -in 1709 Gusmao applied to the King for a patent and sole right to some -such invention, desiring an injunction and severe penalty against -all infringements. The application sets forth a machine capable of -journeying through the air faster than over land or sea, competent -to carry messages five or six hundred miles a day to troops, or the -most distant countries, and even adequate to explore regions about the -poles. Quite a modern promoter Señor Gusmao. The King in reply issued -the following decree: - - “Agreeably to the advice of my council, I order the pain of - death against the transgressor. And in order to encourage the - suppliant to apply himself with zeal toward improving the - machine which is capable of producing the effects mentioned by - him, I also grant him the first Professorship of Mathematics in - my University of Coimbra, and the first vacancy in my College - of Barcelona, with the annual pension of 600,000 reis during - his life.” - -The “patent” seemed liberal enough, and yet Gusmao never resumed -his aërial experiments. He was accused of magic, and may have -feared persecution on that account; accordingly he engaged in naval -construction till 1724, when he left Portugal. - -The first vacuum balloon was proposed by the Jesuit father, Francis -Lana, and described in his book _Podromo dell’Arte Maestra Brecia_, -which appeared in 1670. Though not a practical project like Gusmao’s, -it was very ingenious, and marks an interesting phase in the evolution -of the fundamental idea of the air ship, or “balloon” as it was called -by the inventor, who then coined the word now in common use. Lana -proposed to use four copper spheres each 25 feet in diameter and -1/225 inches in wall thickness, quite well exhausted of air, to give -ascensional force which he computed at 1,200 pounds aggregate for the -four spheres. From these he would suspend the passengers in a boat -having a mast and sail to propel the ship in time of favorable wind. -Having computed the buoyancy according to well-known physical laws, he -could see no possible objection to his project “unless,” he writes, -“it be that God would never permit this invention to be practically -applied, in order to prevent the consequences that would ensue -therefrom in the civil and political government of men.” - -[Illustration: FIG. 4.—LANA’S PROPOSED VACUUM BALLOON.] - -Of recent years inventors having less delicate scruples about -embarrassing Providence, have revived Lana’s project with -improvements. It has been proposed to replace the sail by a -motor-driven propeller, and to ensure the hull against collapse from -the prodigious external air pressure—a ton per square foot—by ample -internal bracing. Even within the past twelve months this scheme has -been soberly advocated by several technical journals and by the author -of an elaborate book on aërial warfare. To a mathematician this is -amusing, when not too pathetic; for it can be rigorously proved that -no vacuum balloon of present day material, whatever its design, can -possibly resist crushing if made light enough to float. - -In 1887 Walter Wellman described in the _Associated Press_ a steel -vacuum balloon 144 feet in diameter and 654 feet long in which a -Chicago doctor proposed to carry passengers to the North Pole, at -incredible speed, if they would furnish him $130,000 to meet the -expenses of construction. “Here is a most excellent opportunity,” wrote -Wellman, “for all who would like to win fame by being one of the party -which shall set foot upon that icy _ignis fatuus_ of many nations and -two centuries.” Two decades later Mr. Wellman organized, after his own -ideas, an aërial expedition to the North Pole; but he no longer favored -starting from Chicago in a vacuum balloon with a party of stockholders. - -It may be added that the inventor of the great steel vacuum balloon, -after organizing the Trans-Continental Aërial Navigation Company, and -failing to raise all of the $130,000, sought aid from the national -government. Here was an interesting situation; a doctor ignorant -of mechanics, with the plans for a mammoth and impossible balloon, -appealing for aid to a congress, supremely shy of air ships, even -though recommended by its ablest military advisers. But in this case -there was a capable lobby. The bill for this physically impossible -balloon actually passed the House, and was finally defeated only by -the timely effort of a few scientific men who, by easy calculation, -proved the absurdity of the invention. As the reader may like to see a -mathematical proof of the impossibility of a vacuum balloon, since such -projects arise frequently, the argument is given in Appendix I. - - - - - PART I - - GROWTH OF AËROSTATION - - - - - CHAPTER I - - EARLY HISTORY OF PASSIVE BALLOONS - - Oh, that I could as smoke arise, - That rolls its black wreathes through the air; - Mix with the clouds, that o’er the skies - Show their light forms, and disappear: - Or like the dust be tossed - By every sportive wind till all be lost! - —ÆSCHYLUS. - - -If desire is sometimes the mother of invention, doubtless the wish to -“mix with the clouds,” or “as smoke arise,” suggested to man his first -means of aërial locomotion. Indeed this is openly avowed by Joseph -Montgolfier. “Smoke rises in the chimney; why not encage this smoke, -and have an available force.” But before describing his fundamental -experiments of 1783, let us notice the less conspicuous ones, -though not less philosophical, of his immediate predecessors in the -development of aëronautic science. - -It has been seen, that many years before 1783, inventors had clearly -conceived the true principle of the balloon, and would be glad to -avail themselves of an element of sufficiently low specific gravity -for aërial flotation. The desired opportunity came when, in 1766, -Henry Cavendish published his experiments, proving that hydrogen is -many times lighter than air. Immediately after this, Dr. Black, the -famous chemist and natural philosopher of Edinburgh, conceived the -idea that a thin light vessel filled with hydrogen should be able to -float and rise in the atmosphere, ideas that he conveyed to his friends -and expressed in his lectures a year or two after the appearance of -Cavendish’s publication. But he contented himself with merely pointing -the way to an obviously practicable invention, leaving, as a university -professor should, the development of the scientific idea to inventors -and constructive engineers. - -Intermediate between Dr. Black, the pure scientist, and the Montgolfier -brothers manufacturers, came Tiberius Cavallo, an Italian philosopher -living in England, who made the first small hydrogen balloons. In -a note presented to the Royal Society of London, June 20, 1782, he -relates experiments that seem to entitle him to all the credit of -inventing the balloon except success on a practical scale. He made -hydrogen soap bubbles which rose beautifully in the air, an experiment -that has been repeated throughout the world in every chemical -laboratory since his day. He made a variety of gum bubbles and varnish -bubbles inflated with hydrogen; but curiously enough these failed -to rise, though it is known that such bubbles can be made to float -handsomely.[5] He inflated carefully prepared gold-beater skin and -failed, though gold-beater skin balloons, both large and small, are now -a marketable commodity. Finally he constructed paper balloons which he -tried to float by use of hydrogen, but without success, though a year -later the Montgolfier brothers easily made paper bags arise with hot -air, and Professor Charles ascended in a large silk balloon inflated -with hydrogen. - -The cause of Cavallo’s interesting failures reveals itself in his own -account of one of his pioneer experiments. In his _History and Practice -of Aërostation_, he relates that he constructed, of fine Chinese paper, -a cylindrical balloon having short conical ends and a calculated -buoyancy of twenty-five grains, when properly inflated with hydrogen. -This bag, carefully deflated of air by compression between the hands, -he suspended above a large bottle connected with it by a glass tube, -and supplied with materials for generating hydrogen; in this case a -mixture of dilute sulphuric acid and iron filings. When the hydrogen -was evolving quite rapidly, he expected to see the paper sac expand -and fill out with proportionate speed; but to his surprise it remained -perfectly flat, while the room filled with the strong and disagreeable -odor of the “inflaminable air.” He then realized that the carefully -made sac of paper, which could be so easily inflated with air, was very -permeable to hydrogen, allowing it to escape instantly, as through -porous cloth, or netting. - -Cavallo desisted when the goal was within reach. His plans were -practicable, but he abandoned them too readily. Why did he not varnish -his balloon when it leaked? He could thus so easily have inaugurated -the art of aërial navigation. But after salting the bird’s tail he let -it escape. - -Various accounts have been given of the steps by which the Montgolfiers -were led to their invention of the balloon. They are said to have -studied and discussed projects for aërial locomotion a decade before -hitting upon their first successful device; at one time filling a paper -bag with smoke ineffectually; again with steam, and again trying, but -in vain, to employ hydrogen. The following apparently reliable account -is given by a friend of the Montgolfiers, Baron Gernando, in his -biographical notice of Joseph Montgolfier, having obtained the story -from the inventor himself. - -Joseph Montgolfier found himself at Abignon, and it was at the time -when the combined armies held the siege of Gibraltar. Alone, in the -chimney corner, dreaming, as usual, he was contemplating a sort of cut -that represented the work of the siege; he grew impatient observing -that one could not reach the body of the place either by land or -sea. “But could not one arrive there through the air? Smoke rises in -the chimney; why not store this smoke in such a manner as to form an -available force?” His mind calculated instantly the weight of a given -surface of paper, or taffeta; he constructed without delay his little -balloon, and saw it rise from the floor, to the great surprise of his -hostess, and with a peculiar joy. He wrote on the spot, to his brother -then at Annonay: “Prepare immediately a supply of taffeta and cordage, -and you shall see the most astonishing thing in the world.” - -A quainter story is told by Brisson in his _Dictionary of Physics_. He -says: “I can only repeat what the citizen Montgolfier himself told me, -when he came to Paris to announce his discovery; that the citizeness -Montgolfier having placed a skirt on an open-wicker basket, such as -women use to dry linen, the skirt was lifted to the ceiling. It is from -this fact that the citizens Montgolfier started.” - -Whatever the preliminaries, the Montgolfier brothers finally made the -experiment of holding a paper bag over a fire fed with wet straw and -wool. It is doubtful whether they purposed to fill it with smoke, or -with hot air or an electrical cloud. They knew that a cloud of some -kind rises from such a fire, and they wanted to harness it. Their -first balloon took fire and went up as smoke. But they were rich -paper manufacturers, and soon had another balloon of 700 cubic feet -capacity. This rose from the fire to a height of 1,000 feet, carrying -no fuel with it. Thus two practical[6] men had made fire lift a paper -sac; let the Academy explain how. The baby Aërostation was born. - -How fortuitous the primal steps of science! Galvanism from the twitch -of a frog’s leg; aërostation from the puff of a petticoat! There had -been no year in thirty centuries when people could not easily have -built a hot-air balloon. All the materials were available; only a -little thought was wanting. A simple sketch sent to a Roman tailor, -or tent-maker, could have furnished a woven bag competent to lift -passengers from the heart of the Coliseum, to the wonder and delight -of a hundred thousand spectators. Yet the genius that could design the -Coliseum, or cover its vast enclosure with canvas, failed to think of -the magic bag that would have enhanced so much the ingenious shows of -a show-loving people. That device was an inspiration destined to a -common Frenchman at no uncommon period of science. The hydrogen balloon -arrived in the natural and logical order of scientific progression; -but the hot-air bag might have presented itself at any time since the -birth of weaving. It was a happy thought, like the ophthalmoscope, -or jack-knife—quaint modern creations of constant use or comfort to -mankind. - -The public inauguration of aëronautics occurred on June 5, 1783, at -Annonay, the home of the Montgolfier family, 36 miles from Lyons. -The states of Vivarais being assembled at that place, were invited -to witness the ascension. The Deputies and many spectators found in -the public square an enormous bag which, with its frame, weighed 300 -pounds, and would inflate to a ball 35 feet in diameter. When told -that this huge mass would rise to the clouds they were astonished and -incredulous. The Montgolfiers, however, lit a fire beneath and let the -bag speak for itself. It gradually distended, assuming a beautiful -form, and struggling to free itself from the men who were holding it. -At a given signal it was released; it ascended rapidly, and in ten -minutes attained a height of 6,000 feet. It drifted a mile and a half -and sank gently to the ground. - -[Illustration: FIG. 5.—MONTGOLFIER’S EXPERIMENTAL BALLOON.] - -When the French Academy learned of this event they desired to have -an ascension in Paris, and at once started a public subscription to -defray the expense of constructing and inflating a balloon. They -placed the work in charge of the physicist Charles, after inviting the -Montgolfiers to Paris, and finding they could not come immediately. -Charles proved more than a substitute; he became a fertile inventor and -a rival in the new field. Aided by the skill of the Robert brothers, he -made a silk globe varnished with dissolved rubber, and filled it with -hydrogen, which is many times lighter than hot air. The operation of -filling occupied three days, consuming 500 pounds of sulphuric acid and -half a ton of iron. The globe was 13 feet in diameter, and designated -a “balloon,” or big ball. This had next to be moved from the place of -filling, in the Place des Victoires, to the Champ de Mars, two miles -distant, in order to have space enough to accommodate the increasing -crowd of spectators. Accordingly, on the 26th it was conveyed thither, -in the dead of night, preceded by lighted torches, surrounded by a -cortege, and escorted by foot and horse guards. Impressive and weird, -indeed, was this nocturnal caravan of troops and towering globe -advancing slowly through the dark and silent streets. The astonished -cab drivers knelt humbly, hat in hand, while the procession passed. - -The ascent of this, the first hydrogen balloon, was a popular and -a memorable event. The field was lined with troops. The curious -spectators had thronged every thoroughfare and darkened every housetop. -It was an all day festival, inaugurating a peculiarly French science, -with French animation. The booming of cannon announced to all Paris -the impending flight of the balloon. At five o’clock, in the presence -of 50,000 spectators, and in a shower of rain, the balloon rose more -than half a mile and entered the clouds. The people overwhelmed with -surprise and enthusiasm, stood gazing upward, despite the rain, -observing every maneuver till the vessel had ascended and faded from -view. - -[Illustration: FIG. 6.—CHARLES’ FIRST HYDROGEN BALLOON.] - -The landing of this little balloon did not leave it in a condition to -exhibit proudly to future generations. After drifting three quarters -of an hour, it fell in a field near Gonesse, a village fifteen miles -from the place of ascension, apparently ruptured from overdistention. -The villagers flocked about it with curiosity and trepidation, ignorant -of its nature, whether of bird kind or monster; and doubtful of its -origin, whether natural or satanic. They fell upon it with flails and -pitchforks. When struck it smelt strongly of sulphur, indicating a -diabolic source. They finally hitched it to the tail of a horse which -galloping away in terror, badly damaged it. Whether this destruction -was wrought through fear or rustic hilarity, it induced the government -of France to issue a notice to the public explaining the innocuous -nature of a simple balloon. - -In the meantime Joseph Montgolfier, having reached Paris, had -constructed a waterproof linen balloon 46 feet in diameter and -ornamented in oil colors, which was to be publicly launched at -Versailles. On September 19, 1783, the king and queen, the court and a -vast throng of people of every rank and age, assembled to witness the -ascension. Montgolfier explained to them every detail, and finally lit -the fire, about one o’clock. The great bag gradually expanded, rounding -out in eleven minutes to a beautiful globular form, tugging upward with -a force of seven hundred pounds. Beneath was suspended a wicker cage -containing the first aërial passengers—a sheep, a rooster and a duck. -The vessel rose majestically above the applauding multitude to a height -of fourteen hundred feet, and drifted some two miles in eight minutes, -descending gradually in the wood at Vaucresson. The animals were tipped -out on landing; but, when found by two game-keepers, they were none the -worse for their strange journey. The sheep was grazing and the cock -crowing, says one report, while another relates that the sheep had -trampled on the rooster and lamed him. - -Stephen Montgolfier now wishing to send up human passengers, made a -balloon of 100,000 cubic feet capacity. It was shaped like a full lemon -pointing upward, with a cylindrical neck below, 16 feet in diameter. -Around this neck was a wicker balcony three feet wide, to carry the -aëronauts, bundles of straw for fuel, pails of water and sponges to -extinguish incipient conflagrations, here and there in the balloon, -during a journey. Through stokeholes in the side of the neck sheaves -of straw could be forked to the grate suspended centrally below by -radial chains. During inflation the base of the balloon rested on a -platform, and its top was supported by a rope stretched between two -poles. The vessel when completed, in a garden of the Faubourg St. -Antoine, was 85 feet high by 48 feet across, and weighed 1,600 pounds. -About its zone, painted in oil, were elegant decorations; portraits, -cyphers of the king’s name, fleur-de-lis, with fancy borders below and -above; while higher still, on the arching dome of the bag, were all the -signs of the celestial zodiac. - -The handsome vessel was now ready; but what daring captain should -navigate her? King Louis proposed two prisoners who were under sentence -of death, and had to be killed somehow. But the brave Pilâtre de -Rozier protested indignantly: “Eh quoi! de vils criminels auraient -les premiers la gloire de senlever dans les airs! Non, non, cela ne -sera point.” He stirred up the city, and finally prevailed, through -the entreaties of the Marquis d’Arlandes, who secured from the king -permission to accompany his friend. - -After some days of preliminary practice in maneuvering the tethered -balloon, these gentlemen were ready for an aërial voyage. On November -21, 1783, the balloon was inflated in the garden of La Muette palace, -and stocked with enough straw for an hour’s journey. When all was ready -Pilâtre de Rozier and the Marquis d’Arlandes stepped with eager courage -into the gallery taking opposite sides to ensure proper balance. At two -o’clock they rose splendidly, amid the acclamations of a vast throng -of spectators, and at the height of 280 feet, removing their hats, -saluted the surprised multitude. Encountering a south blowing wind, -they drifted five miles in some twenty minutes, and landed safely in a -field. The apparatus was soon assembled on a cart and returned to the -Faubourg St. Antoine, where it was originally constructed. The details -of this first human voyage in a balloon are very interesting and well -told in a letter written by the Marquis d’Arlande to a member of the -French Academy. - -[Illustration: FIG. 7.—MONTGOLFIER’S PASSENGER BALLOON.] - -“At this time M. Pilâtre said: ‘You do nothing, and we shall not -mount.’ ‘Pardon me,’ I replied. I threw a truss of straw upon the -fire, stirring it a little at the same time, and then quickly turned -my face back again; but I could no longer see La Muette. Astonished, -I gave a look to the direction of the river.... M. Pilâtre then said, -‘See, there is the river, and observe that we descend.’ ‘Well, then, -my friend, let us increase the fire;’ and we worked away. But instead -of crossing the river, as our direction seemed to indicate, which -carried us over the house of the Invalides, we passed along the island -of Cygnes, reëntered over the principal bed of the river, and advanced -up it as far as the gate de la Conference. I said to my intrepid -companion: ‘See, there is the river &c.’ I stirred the fire, and took -with the fork a truss of straw, which from being too tight, did not -take fire very easily. I lifted it and shook it in the middle of the -flame. The next moment I felt as if I were lifted up from under the -arms, and said to my companion, ‘Now we mount, &c.’ At the same time -I heard a noise toward the top of the machine, as if it were going to -burst; I looked, but did not see anything. However, as I was looking -up, I felt a shock, which was the only one I experienced. The direction -of the motion was from the upper part downwards. I said then: ‘What -are you doing? Are you dancing?’ ‘I don’t stir,’ said he. ‘So much the -better,’ I replied, ‘it is then a new current, which, I hope, will push -us over the river.’ In fact, I turned myself in order to see where we -were, and I found myself between l’École Militaire and les Invalides, -beyond which place we had already gone about 2,500 feet. M. Pilâtre -said at the same time: ‘We are on the plain.’ ‘Yes,’ said I, ‘and -we advance.’ ‘Work on,’ said he. I then heard another noise in the -machine, which appeared to be the effect of a rope breaking. This fresh -admonition made me examine attentively the interior of our habitation. -I saw that the part of the machine which was turned toward the south -was full of round holes, many of which were of a considerable size. I -then said: ‘We must descend,’ and at the same time I took the sponge -and easily extinguished the fire, which was round some holes that I -could reach; but leaning on the lower part of the linen, to observe -whether it adhered firmly to the surrounding circle, I found that the -linen was easily separated from it, on which I repeated that it was -necessary to descend. My companion said: ‘We are over Paris.’ ‘Never -mind that,’ said I, ‘but look if there appears any danger for you on -your side—are you safe?’ He said: ‘Yes.’ I examined my side, and found -that there was no danger to apprehend. Farther, I wetted with a sponge -those cords which were within my reach. They all resisted, except two, -which gave way. I then said: ‘We may pass over Paris.’ In doing this, -we approached the tops of houses very sensibly; we increased the fire, -and rose with the greatest ease. I looked below me, and perfectly -discovered the Mission Étranger. It seemed as if we were going toward -Saint-Sulpice, which I could perceive through the aperture of our -machine. On rising a current of air made us leave this direction, and -carried us toward the south. I saw on my left a sort of forest, which -I took to be the Luxembourg; we passed over the Boulevard, and then I -said: ‘Let us now descend.’ The fire was nearly extinguished; but the -intrepid M. Pilâtre, who never loses his presence of mind, and who -went forward, imagining that we were going against the mills that are -between Petite Gentilly and the Boulevard, admonished me. I threw a -bundle of straw on the fire, and shaking it in order to inflame it more -easily, we rose, and a new current carried us a little toward our left. -M. Rozier said again: ‘Take care of the mills’; but as I was looking -through the aperture of the machine, I could observe more accurately -that we could not meet with them, and said: ‘We are there.’ The moment -after, I observed that we went over a piece of water, which I took -for the river, but after landing, I recollected that it was the piece -of water, &c. The moment we touched the ground, I raised myself up to -the gallery and perceived the upper part of the machine to press very -gently on my head, I pushed it back, and jumped out of the gallery, and -on turning toward the machine, expected to find it distended, but was -surprised to find it perfectly emptied and quite flattened, &c.” - -While the foregoing experiment was in progress, plans were matured for -the construction of a hydrogen balloon large enough to support two -passengers and remain aloft many hours, without the need of carrying -dangerous fuel. This type of balloon, called a _Charlière_, after its -inventor, was destined largely to supersede the hot-air type, known -as the _Montgolfière_, and indeed, to replace it entirely for free -voyages of considerable endurance and for most power voyages. The -construction after the plan of Professor Charles was delegated to two -very intelligent mechanics, the Robert brothers who also had succeeded -in dissolving caoutchouc, and thus producing a very superior balloon -varnish. The project was first announced in the _Journal de Paris_ of -the 19th of November 1783. As usual in those days of public enthusiasm, -a subscription was opened to defray the expenses of the experiment, -estimated to cost about ten thousand francs. - -[Illustration: FIG. 8.—CHARLES’ PASSENGER BALLOON.] - -This balloon was a truly scientific creation, which advanced -aërostation from tottering infancy almost to full prime. The bag was -a sphere 27½ feet in diameter made of gores of varnished silk. A net -covered the upper half and was fastened to a horizontal hoop girding -the middle of the globe, and called the “equator.” From the equator -depended ropes which supported, just below the spherical bag, a wicker -boat measuring eight feet by four, covered with painted linen and -beautifully ornamented. The balloon had at the bottom a silk neck 7 -inches in diameter, to admit the gas during inflation, and at the top, -a valve which could be opened by means of a cord in the boat to let -out gas during a voyage, so as to lower the balloon, or to relieve -excessive pressure. In the boat were carried sand ballast to regulate -the height of ascension, a barometer to measure the elevation, anchor -and rope for landing, a thermometer, notebook, provisions, and all the -paraphernalia of a scientific voyage. Barring the fancy boat, this is -almost a description of a good modern balloon. - -The inflation and ascension occurred in the Garden of the Tuileries, -where the limp bag was initially suspended from a rope stretched -between two trees. For three days and nights the hydrogen, drawn from -twenty barrels containing iron and dilute sulphuric acid, poured upward -through the silken neck into the distending globe, which swelled in -volume to 1,400 cubic feet. Finally on a beautiful day, the first of -December 1783, the Tuileries and all the neighborhood were crowded with -spectators. A numerous guard of soldiers, stationed about the apparatus -and grounds, preserved order. The fashion and nobility of Paris were -there, in ample splendor, attracted by the novelty and importance -of the experiment, and the fame of the inventor. Shortly before two -o’clock Professor Charles presented to his friend, Montgolfier, a pilot -balloon six feet in diameter, saying, “It is your prerogative to blaze -the way through the sky.” The pilot balloon was released, showing to -everyone the direction of the aërial currents. Charles and Roberts -stepped into the boat, seated themselves, and quickly rose into the -sky. The multitude gazed in silent wonder. Presently they observed two -pennants waving high above them, though the navigators were scarcely -visible; whereupon they burst forth into wild enthusiasm and thunderous -applause. - -Immediately a cavalcade set out in hot pursuit of the venturesome -sailors. It was the first chase after an air ship, and a most vigorous -one. The balloon drifting northwestward at a speed of fifteen miles -an hour, crossed the Seine, passed over several towns and villages, -to the great astonishment of the inhabitants, and landed in a field -near Nesle. Here it was securely held by friendly peasants, to await -the advent of the official witnesses. Presently these arrived, drew -up a certificate of descent and signed it. The Duke de Chartres, and -the Duke de Fitz-James, who had followed less swiftly, now rode up -and signed the formal document, to the great gratification of the -aëronauts. The aërial journey had been a most delightful one, lasting -about two hours and covering nearly thirty miles. - -After receiving the felicitations of his friends, Charles determined -to reascend, in order to obtain further scientific observations. Owing -to leakage and loss of buoyancy, he must now leave behind his pleasant -companion. He had proposed replacing with earth, or stones, a part -of Mr. Robert’s weight, but, finding none at hand, he signaled the -peasants to let go, whereupon he rose with unusual speed. The remainder -of this first and very remarkable scientific voyage is well told by the -navigator himself: - - “In twenty minutes I was 1,500 fathoms high; out of sight of - all terrestrial objects. I had taken the necessary precautions - against the explosion of the globe, and prepared to make the - observations which I had promised myself. In order to observe - the barometer and thermometer, placed at the end of the car, - without altering the center of gravity, I knelt down in the - middle, stretching forward my body and one leg, holding my - watch in my left hand, and my pen and the string of the valve - in my right, waiting for the event. The globe, which, at my - setting out, was rather flaccid, swelled insensibly. The air - escaped in great quantities at the silken tube. I drew the - valve from time to time, to give it two vents; and I continued - to ascend, still losing air, which issued out hissing, and - became visible, like a warm vapor in a cold atmosphere. The - reason of this phenomenon is obvious. On earth, the thermometer - was 47°, or 15° above freezing point; after ten minutes’ ascent - it was only 21°, or 11° below. The inflammable air had not - had time to recover the equilibrium of its temperature. Its - elastic equilibrium being quicker than that of the heat, there - must escape a greater quantity than that which the external - dilatation of the air could determine by its least pressure. - For myself, though exposed to the open air, I passed in ten - minutes from the warmth of spring to the cold of winter; a - sharp dry cold, but not too much to be borne. I declare that, - in the first moment, I felt nothing disagreeable in the sudden - change. When the barometer ceased to fall, I marked exactly - 18 inches 10 lines (20-01 in. English), the mercury suffering - no sensible oscillation. From this I deduce a height of 1,524 - fathoms (3,100 yards), or thereabouts, till I can be more exact - in my calculation. In a few minutes more, my fingers were - benumbed by the cold, so that I could not hold my pen. I was - now stationary as to the rising and falling, and moved only in - an horizontal direction. I rose up in the middle of the car - to contemplate the scene around me. At my setting out the sun - was set on the valleys; he soon rose for me alone, who was the - only luminous body in the horizon, and all the rest of nature - in shade; he, however, presently disappeared, and I had the - pleasure of seeing him set twice in the same day. I beheld, - for a few seconds, the circumambient air and the vapors rising - from the valleys and rivers. The clouds seemed to rise from the - earth and collect one upon the other, still preserving their - usual form, only their color was gray and monotonous from the - want of light in the atmosphere. The moon alone enlightened - them, and showed me that I was tacking about twice; and I - observed certain currents that brought me back again. I had - several sensible deviations; and observed, with surprise, the - effects of the wind, and saw the streamers of my banners point - upwards. This phenomenon was not the effect of the ascent or - descent, for then I moved horizontally. At that instant I - conceived, perhaps a little too hastily, the idea of being able - to steer one’s course. In the midst of my transport I felt a - violent pain in my right ear and jaw, which I ascribed to the - dilatation of the air, in the cellular construction of those - organs, as much as to the cold of the external air. I was in a - waistcoat and bareheaded. I immediately put on a woolen cap, - yet the pain did not go off but as I gradually descended. For - seven or eight minutes I had ceased to ascend; the condensation - of the internal inflammable air rather made me descend. I now - recollected my promise to return in half an hour, and, pulling - the string of the valve, I came down. The globe was now so much - emptied, that it appeared only a half globe. I perceived a - fine ploughed field near the wood of Tour du Lay, and hastened - my descent. When I was between twenty or thirty fathoms from - the earth I threw out hastily two or three pounds of ballast, - and became for a moment stationary, till I descended gently - in the field, about a league from the place whence I set out. - The frequent deviations and turnings about make me imagine - that the voyage was near three leagues, and I was gone about - thirty-three minutes. Such is the certainty of the combinations - of our aërostatic machine, that I might have kept in the air at - least for twenty-four hours longer.” - -Further interesting details of the first balloon experiments at Paris -are furnished by Dr. Benjamin Franklin, then American Minister to -France, in his letters written to Sir Joseph Banks, President of -the Royal Society of London, and presented in Appendix II of this -book. These quaint and substantial stories are well worth perusal -as the expressions of a great diplomat and philosopher who, in the -midst of social and political activities, found time for scientific -correspondence with his friends in both hemispheres. - -Aërial navigation was now become a practical art which should advance -rapidly in popularity, in both Europe and America. Very soon ascensions -were made everywhere, for private amusement and for public exhibitions. -Not a few were made for scientific, for military and for topographical -purposes; thus giving the art a utilitarian as well as a sporting -feature. It will be interesting to note some of the more conspicuous -ascensions, voyages and improvements made in passive balloons -subsequently to the invention of _Montgolfières_ and _Charlières_. - -The largest hot-air balloon ever constructed, _La Flesselle_, was -launched from the suburbs of the city of Lyons on January 19, 1784, -just two months after the ascent of the first human passengers. It was -also one of the most troublesome to assemble and keep in repair. Day by -day, for more than a week, the balloon was inflated for the purpose of -attaching the ropes to support the great gallery. But the wind blew -dreadfully at times; rain and snow fell on the machine; frost and ice -covered the huge bag; many rents ensued, demanding frequent repairs. -On one occasion, when fed too freely with flame from straw sprinkled -with alcohol, the monstrous ship rose so vigorously as to drag fifty -men with it some distance along the ground. Finally on the 19th of -January, when the weather moderated, the operators built small fires -under the scaffold below the balloon, and thawed away the ice from -the drenched and frozen bag. Then they stocked its gallery with straw -and pitchforks, with fire extinguishers, and other provisions for the -journey. The inflation beginning about noon, occupied but seventeen -minutes. The balloon swelled out rapidly, with the roaring flames -ascending inside, and at last stood forth huge and majestic before -the admiring multitude—a towering thing of magic growth, 100 feet in -diameter by 130 feet high. - -The ascension of this gigantic vessel was immensely spectacular; but -it was also most adventurous and foolhardy. The great bag, which at -best was made of poor materials, was in bad repair after its frequent -inflations. But of the six passengers in the gallery not one could be -induced to remain behind to lessen the risk to the others. Their pilot, -M. de Rozier, remonstrated with them; the proprietor M. C. Flesselle -wished them to cast lots; but no one would abandon the journey. So, -with fear and reluctance, the pilot ordered the mooring ropes to be -cut. Just as the ascent began, a seventh passenger, M. Fontaine, sprang -into the gallery and sailed aloft with the others. By vigorous stoking -the aërial sailors urged their fiery vessel upward three thousand feet, -whence, apparently without fear, they waved their hats to the vast -throng below. - -[Illustration: FIG. 9.—LA FLESSELLE.] - -The spectators were now in a frenzy of excitement. For more than a week -they had vacillated between hope and disappointment; but now they saw -the huge ship soaring into the sky, perhaps on her way to destruction. -They heard the blast of martial music and the booming of mortars. Then -the accumulated emotion of the multitude burst forth. Exclamations -of joy, shrieks of fear, thunders of applause resounded above the -sea of people. Finally the balloon began to burst, a dangerous rent -running vertically along her side. The machine descended with great -rapidity, to the alarm of everyone. It is reported that not fewer than -sixty thousand people ran to the place of landing, with the greatest -apprehension for the lives of the travelers. But the adventurous men -stepped forth from the gallery, after a fifteen minutes’ voyage, -without hurt of any kind, save an insignificant scratch borne by Joseph -Montgolfier, who on this occasion made his first and last ascension. -This was also the first and last ascension of that gigantic fire -balloon; for although it furnished a world of delirious emotion and -excitement, the trouble of inflating the vessel was too great to be -repeated. - -The crossing of the English Channel by balloon had been contemplated -many months by various adventurous spirits; and at length, on a fine -day, the seventh of January, 1785, this feat was attempted by two -intrepid men, the French aëronaut, M. Blanchard, and an American -physician, Dr. Jeffries, who had graduated at Harvard in 1763, and -was practicing medicine in England. Starting from the perpendicular -cliff at Dover Castle, at one o’clock, they sailed in the direction of -Calais, having with them only thirty pounds of sand ballast. This was -too little for so long a voyage; but it would doubtless carry them a -few miles, in the favorable breeze then blowing. To their surprise, -the atmosphere seemed to grow lighter as they advanced over the water, -letting them sink too freely. As they approached mid-channel they -were compelled to discharge all their ballast in order to maintain -their level. But the balloon still descended, seemingly attracted by -the water. Then they ejected a parcel of books to gain a moment’s -relief. When three-fourths across the Channel they sighted the French -Coast, which now they yearned to see at closer range; for the balloon -was contracting and sinking rapidly. They threw out from the boat -everything available, wings, anchors, cords, provisions; yet they saw -the vessel persistently approaching the sea. Finally they cast off part -of their clothing, fastened themselves to the cords suspended from -the balloon-ring, and prepared to cut away the boat. But presently -approaching the coast near Calais, they began to rise; then ascended -rapidly, soaring in a magnificent arch above the high grounds. At -last they descended gradually above the forest of Guines, seized the -branches of a tree to stop their flight, and at three o’clock were -happily landed. It was a thrilling voyage of two hours, and made a -profound impression at the time. As a mark of appreciation the King -presented Blanchard a sum of 12,000 francs and a pension of 1,200 -francs per year. The people erected a monument on the place of landing -to commemorate this extraordinary voyage. - -This splendid achievement incited two Frenchmen to attempt a counter -voyage which ended disastrously. On June 15, 1785, Pilâtre de Rozier -and M. Romain set out from Boulogne on a voyage from France to -England, in a compound balloon composed of a hydrogen balloon forty -feet in diameter, below which was suspended a fire balloon ten feet -in diameter. They hoped by judicious stoking of the lower balloon to -obviate the sinking tendency suffered by Blanchard and Jeffries. But -the smaller globe proved a fatal auxiliary. Scarcely a quarter of an -hour after launching, the whole apparatus was aflame at an altitude of -3,000 feet, and presently fell in charred and hideous fragments upon -the seashore. M. Romain still showed some signs of life, but Pilâtre -de Rozier was completely dead and all his bones were broken. They were -the first martyrs in the cause of the new science. Poor De Rozier -knew on starting that his apparatus was in bad condition, but he had -received for the purpose a sum of money from a distinguished patron, -and therefore felt obliged in honor to attempt the voyage. He was -twenty-eight years old and engaged to be married to a young lady in the -convent at Boulogne, who eight days after the catastrophe which robbed -her of her fiancé, died brokenhearted and in convulsions. - - - - - CHAPTER II - - PRACTICAL DEVELOPMENT OF PASSIVE BALLOONS - - -The next important advance in practical ballooning was made by the -substitution of coal gas for hydrogen. This was England’s contribution -to an art which previously had not greatly flourished west of the -Channel. It was a contribution following the natural growth of science; -for in 1814 coal gas began generally to be used for lighting London, -and seven years later for inflating balloons. This valuable innovation -was made by the famous aëronaut, Charles Green, on the occasion of his -first ascension, made July 19, 1821, the coronation day of George IV. -The new method largely superseded the old, extending throughout the -world with the spread of gas lighting; and it gave a powerful stimulus -to aëronautics by rendering inflation cheap and convenient. Mr. Green -himself made 526 ascensions during his life, or at the rate of one -cruise a month for nearly forty-four years. In due time, every country -had its professional aëronauts, and finally its amateurs, who, forming -themselves into aëro clubs, devoted themselves to racing in free -balloons, inflated quite usually from a city gas supply. - -In 1836 Mr. Robert Holland organized an expedition designed to test the -utmost capabilities of the balloon of his day, particularly in points -of endurance and control. Engaging as pilot the first aëronaut of the -age, Mr. Charles Green, and employing the largest gas balloon that ever -had been constructed, stocked with provisions enough to last three -men a fortnight, he invited a third person, Mr. Monck Mason, to join -them on a cruise from London to wherever the wind would take them, but -preferably to land near Paris, as the balloon was to be delivered there -after the voyage. - -[Illustration: FIG. 10.—THE GREAT BALLOON OF NASSAU.] - -The vessel selected for that famous cruise was _The Great Balloon of -Nassau_, then recently built by Mr. Green and representing all that his -skill and experience could devise. It was of pear shape, formed of -the finest crimson and white silk, “spun, wove and dyed expressly for -the purpose,” and comprising when distended a volume of 85,000 cubic -feet. From its stout balloon-ring six feet in diameter was suspended a -wicker car measuring nine feet long by four wide, having a seat across -either end, and a cushioned bottom to serve as a bed, if such should be -needed. Across the middle of the car was a plank supporting a windlass -for raising or lowering the guide-rope, that is a heavy rope which -could be trailed over land, or water, to keep the balloon at a nearly -constant level without expenditure of ballast, and to check its speed -on landing. This valuable device invented by Mr. Green in 1820, was -now to receive adequate trial, which, indeed, formed one of the chief -purposes of the cruise. Other paraphernalia of the voyage were food -and drink, warm clothing, lamps, trumpets, telescopes, barometers, a -quicklime coffee-heater, a grapnel and cable, and a ton of sand ballast -in bags. - -The voyage proved well worthy of the elaborate preparations. At -one-thirty o’clock on November 7th, the three navigators arose -from London, in presence of a mighty multitude, and drifted in a -southeasterly direction traversing the cultivated plains of Kent, and -in two hours passed the environs of Canterbury. Here they dropped -a parachute with a letter for the Mayor, which he duly received. -Continuing their journey they floated leisurely above the tree tops, -talking to the inhabitants of the country, startling the fleet-winged -quail, terrifying a colony of rooks, and finally reaching Dover at -sundown, where they again dropped a letter for the Mayor of the city, -which also was duly delivered. - -Without a moment’s pause they drifted over the Channel into the -gathering darkness. Before them rose a huge wall of vapor and black -clouds standing on the bosom of the sea; behind them the twinkling -lights and the music of breakers rolling on a hospitable shore. -Presently they were immersed in a region of absolute silence and -impenetrable darkness. At times this deep stratum would slowly -dissolve, revealing a glimpse of the dusky ocean and a passing ship; -then some huge wreath of vapor would involve them in bottomless gloom, -without perspective, without apparent motion, without a sound to cheer -or mark their dubious course. Now to avoid the risk of settling too -near the sea, as Blanchard and Jeffries had done, they were preparing -to let down the guide-rope with floating ballast attached, when -suddenly they emerged from the pall of darkness, and were greeted by -the glittering lights of Calais, and the gentle sound of waters dashing -upon the beach. They had crossed the Channel in one hour, and were -soaring serenely three thousand feet above the ocean, not having to -lower the guide-rope to preserve their elevation. - -Now came the preparations for a night voyage over an obscurely defined -land route. A simple rope one thousand feet long without ballast was -allowed to trail beneath them. A lamp was lit. Coffee was heated by the -slacking of quicklime. An ample store of viands and wine was spread on -the board in the middle of the car. The strenuous period of thought and -labor was past, and now three hungry men sat leisurely at dinner, after -a fast of twelve long hours. However sparing of bones and bottles, -which later might serve as ballast, they were not economical of food -and wine that evening. For the present they had only to live and be -happy as bachelors. Muffled in soft garments, well fed, abundantly -served with divine beverages, hot or cold; what finer picture of -masculine comfort and delight? - -They were now floating tranquilly in the vast solitude of heaven, over -a teeming continent mantled in night and mystery. Far along earth’s -sable surface gleam the scattered fires of many villages; and above -it the lovelier fires of a moonless sky. Unseen, unsuspected, they -survey kingdoms and cities, trailing their long rope serpent-like -over woodland, field and quiet homestead. Now on the horizon before -them looms a greater fire, like a distant conflagration, widening as -they approach. Gradually it expands into a model city, shooting out -long lines of illuminated streets; here the public squares, markets -and theatres; there the rumbling iron mills with blazing furnaces. -They are above Liege at her festive hour, murmuring with animation -and busy life. Again they drift into the dark regions of slumber, -lapped in silence and deep tranquillity, where the lights of men are -extinguished, and the stars, redoubling their lustre, gleam whitest -silver in heaven’s jetty dome. Midnight involves the world; an abyss -of darkness enfolds it; their solitary lamp seems to melt its way -through solid space of blackest marble. For hours they undulate over -the rolling hills, rising and falling a thousand cubits, held always to -earth by the trailing rope. At times they are so near as to trace the -landscape dimly; here a white tract covered lightly with snow, here a -dark valley or forest, here a tortuous river, probably the Rhine, with -its multitudinous thunder of waters. But in all that weird and obscure -wandering no joyous note of human or animal life ascends ere dawn to -cheer their solitary course in the sky. - -At last the paling of the morning star, and a faint tingeing of the -eastern cumuli, announce the expected day. With sudden bound the -great ship mounts aloft twelve thousand feet, into the glory of the -blazing sun, new risen among clouds of amber and purple. Far below, -twilight and mist still mantle the half-awakened world, presenting a -stupendous panorama, vast as an empire. Presently down they plunge into -the vaporous and obscure atmosphere, drifting carelessly, but soon -reascending into the splendor of morning. Thus after making the sun -rise three times and set twice, they float contentedly along the misty -landscape, marveling what region lies below them, whether a barren -wilderness, or the abode of civilized life, with human comforts and a -ready means of transportation. A hot breakfast would be very welcome -now; for they had accidentally dropped the lime pot and had spent the -latter half of the night without warm beverage in a region where oil -and water had frozen. - -At length through the clearing vapor they perceive the country well -tilled and populous; a good place to land to shorten their route to -Paris, and avoid the wide plains of Poland or Russia. They raise the -guide-rope, lower the cable and anchor, open the valve, and descend -in a grassy field near Weilburg, in the Duchy of Nassau. It is now -seven-thirty o’clock, just eighteen hours since starting; and they -have traveled five hundred miles, the longest aërial voyage thus -far recorded. Very soon they are surrounded by a wondering crowd of -pipe-puffing, shaggy-headed, German peasants, by whose willing aid they -finally deflate the balloon, pack it in the bottom of the car, and -mount it on a one-horse cart for Weilburg. Thence the aëronauts, after -a week of festivities in their honor, and distinguished attentions from -the highest officials of the town, embarked with their balloon for -Paris. This famous craft now bore its permanent title; for a few days -previously the lovely daughter of the Baron de Bibra, with seven other -young ladies and Mr. Green, had stood within the air-inflated vessel, -poured a generous libation of wine, and christened the hardy cruiser -_The Great Balloon of Nassau_. - -It was in truth a great balloon in various ways; in solidity and -strength, in workmanship, in completeness of appointment, in endurance -and control. Having accomplished that long journey without a sign -of weakness or defect, it was still in prime condition, proudly -heading for the farthest verge of Europe. It had not, of course, the -instrumental equipment of a modern balloon; but it did possess the -elements essential for a long and hard cruise. Since the day of its -launching many additions have been added to the art, but these, for -the most part, are special adjuncts. The more important features of a -good balloon are practically the same to-day as when they were first -introduced by Professor Charles and sturdy old Mr. Green. - -A still more elaborate and colossal air ship was the _Geant_, -constructed in 1863, for A. Nadar of Paris. It was made of a double -layer of white silk, had a volume of 215,000 cubic feet and a buoyancy -of 4½ tons. The car was a wicker cabin 13 feet wide by 7 feet high, -with a wicker balcony round the top so that the roof could be used -as an observation deck—a delightful place to loll in the starlight, -or watch the morning sun “flatter the mountain tops with sovereign -eye.” The closed car comprised two main rooms with a hallway between -them, one containing the captain’s bed and baggage, the other having -three superposed berths for passengers. Minor divisions of the car -were reserved for provisions, a lavatory, photography and a printing -press, the latter to be used for the dissemination of news from the -sky, as the navigators floated from state to state. A compensator -balloon of 3,500 cubic feet, just below the main bag and connected -with it, received the escaping gas during expansion with increase of -temperature or altitude, and gave it back on contraction. In fact -as well as in name, Nadar’s vessel was a giant. Curiously enough, he -called it the “last balloon,” for he expected to realize enough money -by exhibiting it, to inaugurate successful flying by means of the -helicopter, and thus banish ballooning from the world of futile effort -to the domain of bygone dreams and chimæras. - -[Illustration: FIG. 11.—CAR OF NADAR’S BALLOON.] - -The first ascension, made on Sunday, October 4, 1863, was one of -magnificent promise. In the midst of a vast holiday throng on the Champ -de Mars, the great globe towered aloft nearly two hundred feet, held to -earth by one hundred men and twice as many sand bags. In the car were -fifteen notable passengers including one lady, the fair young Princess -de la Tour d’Auvergne, in morning toilet and a pretty hat. “Lachez -tout!” shouts Captain Nadar, the effervescent photographer of Paris. -Away they soar, heading for St. Petersburg, with provisions enough to -sail beyond the polar sea. - -The captain was now in supreme control, with the key to the victual -and liquor room in his pocket, and his twelve commandments duly signed -by all aboard. They had pledged themselves not to gamble, not to carry -inflammable materials, not to smoke unduly, not to throw bottles -overboard, not to quit the balloon without permission, but to descend -if so ordered, etc. They had sailed at five o’clock in the evening and -all was going merrily. But presently trouble came. The valve rope gave -way, the vessel was sailing in the dark, and the Godards declared she -was drifting to sea, whereas she was drifting in quite the opposite -direction. To be on the safe side they threw out the anchors by -permission of the commander. One anchor broke, but the other took hold -and checked the balloon in spite of the strong wind blowing. At last -after three violent bumps on the ground they landed near Meaux at nine -o’clock in the evening, one passenger sustaining a broken knee, the -others various bruises. It was a grand adventure and all were pleased. - -Two weeks later a second voyage was begun in similar style, and again -from the Champ de Mars, this time in the presence of the King of -France and the young King George of Greece; but now Nadar took along, -not the Princess with the pretty hat, but Madame Nadar, his wife. To -entertain the crowd before starting, thirty-two persons were first sent -aloft 300 feet and drawn back to earth. Finally at five o’clock Sunday -evening, October 18th, a party of nine passengers soared proudly -northward, well provisioned as before, and eager for a long voyage. -They disappeared in the gathering night, leaving their friends much -concerned for their safety and ultimate destination. At half past eight -they were over Compiegne, seventy-eight miles away, drifting near the -ground to say “All goes well” and have the good tidings transmitted -to Paris. At nine they crossed the Belgian frontier; at midnight they -were over Holland; at sunrise they skirted the Zuyder Zee and entered -Hanover; at eight they were coursing headlong toward Nienburg and the -North Sea in the current of a swift west wind. - -They were now in great peril. If they went to sea they might all be -drowned; if they came to earth at such horizontal speed they should -be terribly pounded. Choosing the latter evil, they opened the valve -and threw down the grappling irons. “To the ropes,” shouted the Godard -brothers. Assembling on deck all clung to the suspension ropes to -mitigate the shock of landing. Nadar put his arm about his wife to -protect her. The anchors snatching a tree, uprooted and dragged it -along; then caught and tore off the roof of a house; threshed into -a telegraph line pulling down the wires and poles; struck into some -firmer obstacle and broke off completely, leaving the huge monster -to sweep unchecked in the violent ground current. Owing to trouble -with the valve, the gas could not be liberated quickly; the great -vessel again and again plunged to earth and rebounded high in air, -its ponderous basket crashing through heavy timber, and breaking -down whatever opposed its course. For nine miles they pounded over -the plain by Nienburg toward the sea, dashing into pools, bogs and -thickets, their limbs sprained or broken, their bodies bruised, their -faces splashed with mud. Presently through loss of gas the rebounding -ceased, the basket dragged along the earth squeezing some of the -passengers beneath it, and dumping others out on the ground, leaving -them behind. Those remaining tried to assist Madam Nadar to land, but -they were tumbled out and she was caught under the basket from which -she was extricated with much difficulty, when the balloon was finally -halted. Thus their memorable voyage of seventeen hours, covering 750 -miles, had a terrific, though not fatal ending. One had a broken femur, -another a dislocated thigh, others numerous scratches and contusions. -But no complaint was uttered; for the afflictions were regarded as -natural concomitants to such interesting sport. After some days tender -nursing by the Germans, and solicitous inquiries from the King of -Hanover, they returned to Paris; some indeed on their backs, but for -all that, none the less admired by their countrymen, as survivors of a -marvelous adventure. - -Another valiant English leader in aërostation was James Glaisher, -member of the British Association for the Advancement of Science. -As one of a committee of twelve appointed by that body in 1861, to -explore the higher strata of the atmosphere by means of the balloon, -he volunteered his services as an observer, when no other capable man -could offer to do so. With a professional aëronaut, Mr. Coxwell, and a -new balloon specially constructed for the work, cubing 90,000 feet, he -made eleven ascensions for the society, four from Wolverhampton, seven -from Woolwich. Incidentally he made seventeen other ascents of various -altitude; not at the expense of the committee, but as a scientific -passenger in public balloon ascents advertised beforehand. - -The objects of the enterprise were first to study the physical -conditions of the atmosphere; secondly to study the effect of the -higher regions upon the passengers themselves, and some pigeons, -which they carried along; thirdly to make some observations in -acoustics and magnetism, particularly to determine the period of -oscillation of a magnet at various altitudes. The specific study of -the atmosphere itself was to comprise observations at all altitudes, -of the temperature of the air, its pressure, and percentage of -moisture; observations of the velocity and direction of the wind, -the constitution of the clouds, their height, density and depth, the -constitution and electrical properties of the air. They were also to -collect samples of the air at different elevations, which later might -be examined in the laboratory. Thus the voyages were systematically -planned for scientific research, and were the first thorough attempts -in England, though similar efforts had been made previously in France. -It may be added that Glaisher’s observations were the most important -made during the first century of aëronautics, and may be found fully -detailed by that hardy investigator himself in the British Association -Reports for 1862-66. - -Mr. Glaisher’s most interesting voyage of that memorable series -occurred on September 5, 1862. Starting from Wolverhampton at three -minutes after one o’clock, they soared swiftly upward, passing through -a cloud eleven hundred feet thick and emerging in a glorious field -of sunlight with an amethystine sky above and a boundless sea of -vapor beneath; a sea of rolling hills and mountain chains, with great -snow-white masses steaming up from their surface. They had left the -noisy bustle of earth in the comfortable temperature of 59°; in three -quarters of an hour, they were five miles aloft in a deadly silent -atmosphere, two degrees below zero, and approaching one third its usual -density, the balloon neck white with hoar frost, the men gasping for -breath. Here the observations became increasingly interesting but -immensely more difficult. They are graphically told in the following -extract from Mr. Glaisher’s classical report: - - “I asked Mr. Coxwell to help me to read the instruments, as I - experienced a difficulty in seeing. In consequence, however, - of the rotatory motion of the balloon, which had continued - without ceasing since the earth had been left, the valve-line - had become twisted, and he had to leave the car and mount into - the ring above to adjust it. At this time I looked at the - barometer, and found it to be 10 inches, still decreasing - fast; its true reading therefore, was 9¾ inches, implying a - height of 29,000 feet. Shortly afterwards I laid my arm upon - the table, possessed of its full vigor, and on being desirous - of using it, I found it powerless; it must have lost its power - momentarily. I tried to move the other arm, and found it - powerless also. I then tried to shake myself, and succeeded - in shaking my body. I seemed to have no limbs. I then looked - at the barometer; whilst doing so my head fell on my left - shoulder. I struggled and shook my body again, but could not - move my arms. I got my head upright, but for an instant only, - when it fell on my right shoulder, and then I fell backwards, - my back resting against the side of the car, and my head on - its edge; in this position my eyes were directed towards Mr. - Coxwell in the ring. When I shook my body I seemed to have full - power over the muscles of the back and considerable power over - those of the neck, but none over either my arms or my legs; in - fact I seemed to have none. As in the case of the arms, all - muscular power was lost in an instant from my back and neck. I - dimly saw Mr. Coxwell in the ring and endeavored to speak, but - could not; when in an instant intense black darkness came, the - optic nerve finally lost power suddenly. I was still conscious, - with as active a brain as at the present moment whilst writing - this. I thought I had been seized with asphyxia, and that I - should experience no more, as death would come, unless we - speedily descended; other thoughts were actively entering my - mind, when I suddenly became unconscious as in going to sleep. - I cannot tell anything of the sense of hearing; the perfect - stillness and silence of the regions six miles from the earth - (and at this time we were between six and seven miles high) is - such that no sound reaches the ear. - -PLATE I. - -[Illustration: GLAISHER AND COXWELL.] - -[Illustration: PARSEVAL KITE BALLOON.] - - “My last observation was made at 1 h. and 54 m., at 29,000 - feet. I suppose two or three minutes fully were occupied - between my eyes becoming insensible to seeing fine divisions, - and 1 h. 54 m., and then that two or three minutes more passed - till I was insensible; therefore I think this took place at - about 1 h. 56 m. or 1 h. and 57 m. Whilst powerless I heard - the words, ‘temperature’ and ‘observation,’ and I knew Mr. - Coxwell was in the car speaking to me, and endeavoring to - arouse me, therefore consciousness and hearing had returned. I - then heard him speak more emphatically, but I could not see, - speak or move. I heard him again say, ‘Do try—now do.’ Then I - saw the instruments dimly, then Mr. Coxwell, and very shortly - saw clearly. I rose in my seat and looked round, as though - waking from sleep, though not refreshed by sleep, and said to - Mr. Coxwell, ‘I have been insensible;’ he said, ‘You have; - and I, too, very nearly.’ I then drew up my legs, which had - been extended before me, and took a pencil in my hand to begin - observations. Mr. Coxwell told me he had lost the use of his - hands, which were black, and I poured brandy on them. - - “I resumed my observations at 2 h. 7 m., recording the - barometer reading at 11.53 inches, and temperature −2°. I - suppose three or four minutes were occupied from the time of my - hearing the words ‘temperature’ and ‘observation’ till I began - to observe; if so, then returning consciousness came at 2 h. - and 4 m., and this gives seven minutes for total insensibility. - I found the water in the vessel supplying the wet-bulb - thermometer, which I had by frequent disturbances kept from - freezing, was one solid mass of ice; and it did not all melt - until after we had been on the ground some time. - - “Mr. Coxwell told me that whilst in the ring he felt it - piercingly cold; that hoar-frost was all round the neck of the - balloon. On attempting to leave the ring he found his hands - frozen, and he had to place his arms on the ring and drop - down; that he thought for a moment I had laid back to rest - myself; that he spoke to me without eliciting a reply; that - he then noticed my legs projected and my arms hung down by my - side; that my countenance was serene and placid, without the - earnestness and anxiety he had noticed before going into the - ring, and then it struck him I was insensible. He wished to - approach me, but could not, and he felt insensibility coming - over himself; that he became anxious to open the valve, but in - consequence of having lost the use of his hands he could not, - and ultimately did so by seizing the cord with his teeth and - dipping his head two or three times until the balloon took a - decided turn downwards. This act is quite characteristic of - Mr. Coxwell. I have never yet seen him without a ready means - of meeting every difficulty, as it has arisen, with a cool - self-possession that has always left my mind perfectly easy, - and given me every confidence in his judgment in the management - of so large a balloon. - - “No inconvenience followed the insensibility; and when we - dropped it was in a country where no conveyance of any kind - could be obtained, so that I had to walk between seven or eight - miles. - - “The descent was at first very rapid; we passed downwards three - miles in nine minutes; the balloon’s career was then checked, - and we finally descended in the center of a large grass-field - belonging to Mr. Kersall, at Cold Weston, seven-and-a-half - miles from Ludlow. - - “I have already said that my last observation was made at - a height of 29,000 feet; at this time (1 h. 45 m.) we were - ascending at the rate of 1,000 feet per minute; and when I - resumed observations we were descending at the rate of 2,000 - feet per minute. These two positions must be connected, taking - into account the interval of time between, viz. 13 minutes, - and on those considerations the balloon must have attained - the altitude of 36,000 or 37,000 feet. Again, a very delicate - minimum thermometer read—12, and this would give a height of - 37,000 feet. Mr. Coxwell, on coming from the ring, noticed that - the center of the aneroid barometer, its blue hand, and a rope - attached to the car, were all in the same straight line, and - this gave a reading of 7 inches, and leads to the same result. - Therefore these independent means all lead to about the same - elevation, viz. fully SEVEN MILES. - - “In this ascent six pigeons were taken up. One was thrown out - at the height of three miles, when it extended its wings and - dropped as a piece of paper; a second, at four and five miles, - and it fell downward as a stone. A fourth was thrown out at - four miles on descending. It flew in a circle, and shortly - alighted on the top of the balloon. The two remaining pigeons - were brought down to the ground. One was found to be dead, and - the other, a ‘carrier,’ was still living, but would not leave - the hand when I attempted to throw it off, till after a quarter - of an hour it began to peck a piece of ribbon which encircled - its neck, and was then jerked off the finger, and flew with - some vigor toward Wolverhampton. One of the pigeons returned to - Wolverhampton on Sunday the 7th, and it is the only one that - has been heard of.” - -This was the loftiest ascent ever made up to that time; and thus -Glaisher, or rather Coxwell, who was in the ring above him, could be -called the “highest man” of the first century of aëronautics. Their -greatest elevation, however, is now generally estimated at much less -than seven miles, and probably below six miles, due allowance being -made for inaccuracies of estimate made by Mr. Glaisher. His results, -nevertheless, were considered valuable, revealing as they did, that the -balloon may be used safely up to the neighborhood of five miles; that -the temperature of the atmosphere does not, as previously supposed, -decline one degree for each 300 feet of ascent, but often declines -more rapidly, and sometimes even increases with the elevation for -considerable stretches; that the moisture percentage is extremely -slight at an altitude beyond five miles; that at all elevations -attainable by man the dry- and wet-bulb thermometers can be used -effectively, etc. - -A still loftier ascent was made by Professor Berson of Germany, -aided by the respiration of oxygen. On July 31, 1901, accompanied by -Dr. Süring, he ascended from Berlin in the balloon _Preussen_ to an -elevation of 10,800 meters, which at present constitutes the world’s -record for altitude. The balloon had a capacity of 300,000 cubic feet, -and left the ground two thirds filled with hydrogen, and carrying 8,000 -pounds of ballast in the form of sand bags attached to the sides of the -basket, so that they could be cut loose with the slightest physical -effort. - -The _Preussen_ was one of the largest passive balloons ever -constructed. In cubic capacity it was comparable with the colossal -_Montgolfière_, _La Flesselle_, already described, and the huge free -balloon _Le Geant_, constructed by Nadar in 1863. But all were -eclipsed by the great balloon of Henri Giffard. This latter measured -450,000 cubic feet, and even to-day ranks as the largest captive -balloon ever constructed. It was a familiar object at the Paris -Exposition of 1878, where it was installed by the famous inventor -Henri Giffard, to give sightseers a bird’s-eye view of Paris. It could -take up forty persons at one time, or eight more than once ascended in -Nadar’s _Geant_. - -No serious attempt has been made to surpass the altitude flight of -Professor Berson and Dr. Süring; for though it is easily possible to -carry human beings to a greater height than seven miles, the results -seem hardly to justify the cost. To ascend very much higher would -require an enormous and costly balloon, and to ensure the comfort -of the passenger might require an air-tight car, or armor supplied -continuously with fresh air, or oxygen. Such a suit, or car, however, -can be made very light, since its pressure must naturally be internal; -and it would admit of an extremely rapid change of elevation without -discomfort to the passenger. A steel bottle weighing fifty pounds, -and filled with compressed air, or oxygen, would supply a passenger -several hours, and allow him to breathe under normal pressure. The -total weight of a bottle and air-tight car, or suit, need not exceed -the weight of a man. Moreover, the ballast could be largely dispensed -with, thus admitting of a very rapid ascent from the earth. A celluloid -car would have the advantage of transparency, though it might become -too brittle at very low temperatures. A suit, or car, with glass -portholes would serve in lieu of a celluloid car for transparency. The -usual balloon and basket, carrying a steel bottle, furnishing air at -normal pressure to a man in a rubberized silk suit is a sufficiently -simple and practicable device; the air entering the suit near his -mouth and leaving below through a check valve regulated to maintain the -desired internal pressure. An air-tight silk fabric capable of enduring -safely a tensile stress of 150 pounds per running inch would answer the -purposes. But at present there seems to be no incentive to attempt a -balloon trip exceeding the heights already attained, unless it be that -of notoriety or sentiment. - -The French meteorologists have devised a much simpler and cheaper -method of exploring the upper atmosphere, by use of small balloons -carrying recording instruments. An ordinary silk or gold-beater -skin balloon, partly inflated, ascends to a great height with the -instruments, drifts away losing gas, and on landing is found by some -one who returns it according to written directions accompanying the -craft. Another method, introduced by Professor Assman, is to employ -closed rubber balloons which at great altitudes burst by the expansion -of the hydrogen within them, and allow the instruments to descend -in parachutes softly to the ground. Instrument-carrying balloons of -the above type are called “sounding balloons,” or _balloons sondes_, -whereas if they carry no instruments, but merely show the course of the -wind, they may be called “pilot balloons.” Such sounding balloons have -been used to explore the temperature of the atmosphere to an altitude -of 18 miles. - -In the preceding pages some extended balloon voyages have been -described. These were considered very long in their day, but in recent -years have been surpassed frequently, first by the professional -aëronauts, then by the amateurs and members of various aëronautic -clubs practicing aërostation as a sport, and stimulated by attractive -prizes. But the man who achieved the longest balloon flight during the -first century of the art, seems to have been Mr. John Wise, America’s -foremost pioneer balloonist. - -Mr. Wise was a rare composite of showman, scientist, sport and -dare-devil, who during the four decades succeeding his first ascension -at Philadelphia in 1835, made no fewer than 440 voyages. At first the -aërial art captivated him by the beauty and sublimity of the natural -panoramas witnessed from on high; then he amused himself by dropping -things from the basket and hearing them whistle through space; and -finally he coquetted with the balloon itself, in various ways to -observe the result. On one occasion the neck was choked and the -valve could not be operated, so that when the hydrogen expanded with -increasing altitude, it overstretched the cover and started a rent in -the side of the bag. The balloon descended rapidly, but landed without -injurious shock. - -The audacious aëronaut then decided to make an ascension and -deliberately burst the balloon, by confining the gas in it and throwing -out ballast. But first he tried the experiment on a dog, taking him up -4,000 feet, dropping him in a small collapsed balloon and watching him -settle slowly to earth. Then rising to an altitude of 13,000 feet he -stood debating whether to follow the example of the dog. The balloon -quickly ended the question by exploding at the top. The hydrogen rushed -out with a tempestuous sound, and the great vessel sank swiftly with a -moaning noise of the wind in her rigging. In a few seconds the bag was -empty and collapsed on the top of the net thus forming an effective -parachute. After an exciting fall of more than two miles, Mr. Wise -landed on a farm, with a lively thump, which overturned the basket, and -threw him sprawling on the ground. It was fine sport; he decided at -once to advertise a repetition of it, and thus was led by degrees to -the invention of the ripping panel.[7] - -Mr. Wise firmly believed that a steady wind from west to east prevails -at a height of two miles. He wished to use this for long voyages, and -even contemplated crossing the Atlantic; for he trusted his varnish to -hold hydrogen a fortnight if need be. Accordingly in 1873 the New York -_Daily Graphic_ paid the cost of a balloon to carry him and two others -on that hazardous voyage. The bag had a capacity of 400,000 cubic feet, -but was too frail in construction to receive Mr. Wise’s approval, and -actually burst during inflation when slightly more than three fourths -full. Fortunately, perhaps, for Mr. Wise, he never had an opportunity -to attempt the trans-Atlantic voyage; but on one occasion he enjoyed a -memorable cruise in the great west wind which so took his fancy. Rising -from St. Louis on June 23, 1859, he sailed northeastwardly for twenty -hours, and landed at Henderson, N. Y., having traversed a distance of -809 miles, measured directly. But in attempting another long voyage -with two companions, in September, 1879, he passed over Lake Michigan, -where all were drowned. - -In recent years Mr. Wise’s long voyage has been exceeded several -times. In 1897 M. Godard sailed from Leipsic to Wilna, a distance of -1,032 miles in 24½ hours; but this was not an official flight nor in a -direct course as the crow flies. In October, 1900, M. Balsan voyaged -from Vincennes, France, to Rodom, Russia, a distance of 843 miles in -27 hours and 25 minutes, and De la Vaulx starting from the same point -landed at Korosticheff, Russia, having traversed 1,193 miles in 35¾ -hours. This latter is the longest balloon flight thus far recorded. A -close second to this record was made by A. R. Hawley in his spherical -balloon _America_, aided by Augustus Post, in the Gordon Bennett -International Balloon Race of 1910. Sailing from St. Louis, October -17th, they drifted 1,172.9 miles from their starting point, and landed -in a great forest at Peribonka River, North Lake Chilogoma, Canada, -where they were lost for several days. - -[Illustration: FIG. 12.—DIAGRAM OF A MODERN SPHERICAL BALLOON WITH -RIPPING PANEL.] - -Quite as eventful was the ocean voyage of Walter Wellman, who left -Atlantic City October 15, 1910, for Europe in a motor balloon with a -drag rope, or equilibrator, voyaged with favorable wind to a point -140 miles northeast of Nantucket Island, then was driven by adverse -wind toward Bermuda, and finally rescued by a passing steamer, after -69 hours in the air and a journey of about one thousand miles. A full -account of this strange voyage is given in the New York _Times_ of -October 19, 1910, and in the _Scientific American_ of subsequent date. - -The recent advances in aërostation, though not radically changing the -balloon itself, contribute much to its usefulness and convenience. -Improvements have occurred in the means of inflation and deflation, -in devices for making topographical and meteorological observations, -as also for transmitting and receiving signals. Hydrogen shipped in -steel tubes is now available for easy and rapid inflation, the process -of obtaining it on a large scale making it practically as cheap as -illuminating gas. The ripping panel, invented in 1844 by America’s -foremost pioneer aëronaut, John Wise, is a simple and an excellent -practical device. This is a long patch running longitudinally above the -equator[8] of the balloon, feebly sewed to the envelope, and having a -cord, called the “ripping cord,” extending down to the car along the -outside or inside of the bag, so that the pilot on coming to earth -can let out the gas quickly by tearing a rent in the balloon, thus -flattening it promptly on the earth’s surface, so as to avoid dragging -and bumping if any wind prevails. During an ascension the rise or fall -of the vessel may be instantly noted on the dial of the statoscope, -the temperature, pressure and moisture of the atmosphere may be read -on recording instruments, messages may be sent by telegraph and -telephone either by wire or through space, and sky or landscape may -be photographed if there be sufficient light. The bag itself has been -improved by making it of special fabrics formed of several layers of -silk, or cotton, with thin layers of rubber vulcanized between them -to render the cloth impermeable, also the bag, when not designed to -cleave the wind, is usually given a spherical form which is the figure -of greatest volume for a given surface, the figure originally used by -the inventor of the gas balloon; but when designed to be tethered in -a wind, it is given a longish shape and a tail so that it may ride -the wind like a kite. This type of balloon, though first proposed by -Douglass Archibald about 1845, was first made a practical invention by -Captain von Sigsfeld and Major von Parseval. In a certain sense it is a -tethered motor-balloon, just as a kite is a tethered aëroplane. - - - - - CHAPTER III - - EARLY HISTORY OF POWER BALLOONS - - -Directly after the first launching of human passengers in a crude -aërostat, numerous schemes for controlling the course of a balloon were -evolved. Apparently mere flotation afforded less contentment to the -early pioneer aëronauts than to the free balloonists of the present -hour. Many were eager to apply propelling mechanism to their gas bags, -expecting thus to achieve practical locomotion through the air, even a -generation before the advent of practical steam navigation. Magnificent -dreams they had, indeed, but none the less futile. Few suspected the -enormous power required to propel swift balloons of the very best shape -and size; still fewer realized the impossibility of driving spherical -bags at a practicable velocity. - -On the other hand, it must be said, to the credit of that era of -investigators, that certain noted scientists, after computing the power -required to drive a balloon at high speed, promptly recognized the -inadequacy to that task, of any motors then available. In conjunction -with favorable aërial currents something might be effected; that they -fully grasped; for they knew that the wind frequently has different -directions at different levels. They believed, therefore, that by -causing the craft to rise or fall to a suitable stratum, by use of -various then known devices, it could be made to travel in any direction -at the will of the pilot. Likewise they deemed that the rise and fall -of a balloon, due to change of buoyancy, could be used to propel it, if -sails attached to the vessel were set obliquely to the motion, so as to -receive fair pressure; or if the balloon were made flat, or longish, so -as to glide horizontally, like a kite or parachute. - -Several devices for changing the altitude of the balloon were proposed -or tried. If the vessel were a _Montgolfière_, the mere increase or -lessening of the fire would promptly cause it to rise or fall. If a gas -bag were employed it could be sent up or down by casting out ballast -or opening the valve; or again, as proposed by Pilâtre de Roziere, by -having a _Montgolfière_ underneath the gas balloon, and lifting or -depressing the whole by altering the intensity of the flame. Finally, -an air balloon within a gas balloon was proposed by the Roberts, and a -gas balloon within an air balloon was proposed by General Meusnier, in -either of which combinations, a change of level could be effected by -pumping air into, or letting it escape from, the air bag. All of these -devices can be effected and practically operated by a competent balloon -maker and pilot; and yet they have not enabled man to realize his dream -of navigating the air in all directions without motive power. - -The first attempts at balloon propulsion could not be seriously -regarded by trained engineers, even at the inception of aëronautics; -but still, as infantile steps in the new art, they may deserve passing -notice. - -Blanchard, on March 2, 1784, made the first real effort to steer a -balloon, using for that purpose a spherical gas bag and car provided -with aërial oars and a rudder. As he was about to ascend, however, -from the Champs de Mars, a young officer with drawn sword persisted in -accompanying the pilot, thus compelling Blanchard to leave his wings -on earth to allow sufficient buoyancy for himself and his obtrusive -guest. His first trial was, therefore, frustrated; but subsequent ones -made with that inadequate contrivance also proved futile under the best -circumstances; for the scheme was evidently puerile, though tried by -various grown-up men besides M. Blanchard. - -[Illustration: FIG. 13.—BLANCHARD’S DIRIGIBLE BALLOON, 1784.] - -A no less simple and quaint device for propulsion was that of the -two physicists, the Abbé Miolan and Janinet. The balloon was a -_Montgolfière_ with a large hole in one side, through which the hot air -was to escape with such strong reaction as to drive the bag forward, on -the principle of a lawn sprinkler, or of Newton’s reaction wagon. The -projectors failed, however, to make an ascent, and the crowd becoming -furious destroyed the balloon. - -A more reasonable plan for practical navigation was devised and tried -by the Robert brothers. A melon-shaped balloon, fifty-two feet long by -thirty-two feet in diameter, was made of silk and inflated with pure -hydrogen. Beneath was suspended a longish car of light wood covered -with sky-blue silk. This elegant ship was to be rowed through heaven by -means of six silken oars actuated by sturdy sailors. A silken rudder -should guide her at pleasure when the winds were asleep, or softly -playing in the placid sky. She was a fairy bark, indeed, a soaring -castle lovely to behold. - -After a preliminary trial, accompanied by their patron, the Duke de -Chartres, they were ready for a substantial journey. On September 19, -1784, the vessel was inflated and taken to the Garden of the Tuileries, -in front of the palace, where its cords were held by Marshall Richelieu -and three other noblemen. At eleven forty-five the two Roberts and -their brother-in-law arose and drifted beyond the horizon on a seven -hours’ cruise. Before coming to earth, they plied the oars vigorously, -and described a curve of one kilometer radius, thus deviating 22° from -the feeble wind then prevailing. In a lighter wind they could deviate -still more. They considered, therefore, that the experiment was a -complete success. They had constructed the first elongated balloon, -and had “solved the problem of aërial navigation.” In very happy mood, -therefore, they landed at dusk among the delighted inhabitants of -Artois, where they were graciously met and hospitably entertained by -the Prince de Ghistelles-Richbourg. - -[Illustration: FIG. 14.—ROBERT BROTHERS’ DIRIGIBLE, 1784.] - -The Robert brothers were the first to employ in practice an air bag -inside a gas bag. This was held within the balloon by ropes and -connected with the outer atmosphere by a tube, the idea being to -regulate the internal pressure of the balloon by introducing air into, -or withdrawing it from, the smaller bag. But during an ascension with -their patron, the Duke de Chartres, they entered a violent eddy which -tore away the oars and rudder, at the same time agitating the balloon -so violently that the internal air bag broke its sustaining cords and -fell upon the bottom of the gas bag, thus throttling the connection -with the external atmosphere. The vessel rose swiftly and the gas -expanded dangerously near to the bursting pressure. At a height of -16,000 feet the Duke de Chartres, perceiving the imminent danger of -an explosion of the envelope, drew his sword and cut a rent ten feet -long in its lower part. A part of the gas immediately rushed forth, -and the balloon sank rapidly, but after the discharge of the ballast, -landed safely without further mishap. The Duke acted wisely enough, -but he was afterwards ridiculed for his apparent lack of courage. If -he had possessed more bravery and less caution he might have allowed -the balloon to burst and descend as a parachute, thus anticipating the -spectacular performance of John Wise, in 1838. - -Simultaneously other inventors were evolving designs of no less -importance in the ultimate perfection of the dirigible. In a letter -written to Benjamin Franklin on May 24, 1784, Francis Hopkinson of -Philadelphia proposed to build a balloon of spindle shape and to drive -it by means of a wheel-like propeller at the stern, consisting of vanes -set at an angle to the line of progression, like the common smokejack. -This proposed craft, the harbinger of the modern screw-driven motor -balloon, far antedated the screw-driven boat and the submarine torpedo -which it most resembles.[9] - -While Blanchard and other aëronauts were paddling their globose bags -in search of favorable winds, vainly hoping thereby to direct their -course in the air, General Meusnier of the French army, and member of -the Academy of Sciences, made a systematic study of the requirements -for practical air navigation. After some research on forms suitable -for aëronautic hulls, he designed a power balloon having a pointed -car suspended from a bag of goose-egg form, this latter embodying his -idea of the best shape for a balloon that must cleave the air swiftly -and resist deformation. The propulsion was to be effected by means of -three coaxial screw propellers, supported on the rigging between car -and bag, and actuated by eighty men, for lack of a light artificial -motor. He thus hoped to obtain a moderate velocity which, combined with -skillfully selected air currents, would enable the ship to reach her -destination in ordinary weather. - -[Illustration: FIG. 15.—GEN. MEUSNIER’S PROPOSED DIRIGIBLE, 1784.] - -General Meusnier introduced important special features in the design of -dirigibles for preserving their form and poise. He insisted that the -bag and boat should be so rigidly connected that one could not swerve -from alignment and relative position with the other. He also emphasized -the necessity of preserving the vessel from deformation during flight, -in order to diminish its resistance. To that end he proposed to provide -the hull with a double envelope, the inner one thin and light but -impermeable to hydrogen; the outer one strong and air-tight; the space -between the two envelopes to be pumped full of air under pressure -sufficient to preserve the form of the bag when beating its way swiftly -against a buffeting wind. This was an important invention which in -later years was adopted in many of the most powerful motor balloons—for -all, indeed, except those of the rigid type. He also proposed the -use of stabilizing planes to control the poise of the vessel, thus -anticipating the Lebaudy brothers by more than a century. Like the -Robert brothers he proposed to raise or lower the vessel in search of -suitable currents, by altering the quantity of air in the space between -the inner and outer envelope, by use of hand bellows. - -Apparently General Meusnier and his colleagues were endowed with -constructive genius sufficient to have developed a practical motor -balloon, had they been able to secure a light engine. Lacking this the -early aëronauts could do little more than describe their projects, and -await the growth of the collateral arts and sciences. Accordingly no -substantial advance in motor balloons beyond Meusnier’s designs was -effected till after the middle of the nineteenth century; and until -then the art of aëronautics remained in the hands of showmen. Hundreds -of projects, indeed, were advanced, some exciting considerable interest -and expectation, but nevertheless of such paltry value as hardly to -deserve comment. One notable exception to these was the invention of -Porter in America. - -In 1820 Rufus Porter, a Yankee inventor, and later the original -founder of the _Scientific American_, patented an air ship of very -promising appearance for that early day. Its hull was a long, finely -tapering symmetrical spindle, suspending a car of similar shape by -means of cords, which were vertical at its middle but more and more -slanting toward its ends. Midway between the hull and car was a large -screw propeller actuated by a steam engine in the car. A model of -this dirigible exhibited in Boston and New York, some years later, is -reported to have carried its own power, at fair speed, and to have -obeyed its helm satisfactorily. - -[Illustration: FIG. 16.—RUFUS PORTER’S DIRIGIBLE, 1820.] - -The inventor, being too poor to develop his air ship alone, did -little with the patent during its life; but in 1850 he organized -a stock company to realize the needed funds. From the sale of 300 -five-dollar shares he expected to raise $1,500, and with this sum -build an “aëroport,” 150 feet long, capable of carrying five persons -sixty miles an hour, the whole to be completed in six weeks. Once -this was in operation he would easily command funds sufficient to -build a full-sized vessel adapted to regular passenger service. For, -after careful calculation, he reported that: “It appears certain that -a safe and durable aërial ship (or aëroport) capable of carrying 150 -passengers at a speed of ninety miles an hour, with more perfect safety -than either steamboat or railroad cars, may be constructed for $15,000, -and that the expense of running it would not exceed $25 per day.” - -The language and project seem very modern, even at the present -time, and might well be copied now by a promoter of that identical -project. But it must be observed that the most successful European -experimenters, after spending hundreds of thousands of dollars on giant -air ships, have not yet attained one half the speed contemplated by -that ambitious and chimerical Yankee. The picture was handsome and -alluring, none the less. It may even be said to excel in outward design -any of the air-ship plans produced in either hemisphere before the -middle of the nineteenth century. - -In 1850 a clockmaker and skillful workman, Jullien by name, exhibited -in the Hippodrome, at Paris, a torpedo-shaped model balloon of -gold-beater’s skin, provided with a screw propeller at either side -of its bow, and a double rudder at its stern. It measured 23 feet in -length and weighed 1,100 grammes complete. The propellers were actuated -by spring power, and proved able to drive the tiny vessel against a -moderate wind. The most suitable form for the bag was determined by -towing models through water. - -[Illustration: FIG. 17.—JULLIEN’S MODEL DIRIGIBLE, 1850.] - -Aërodynamically considered, this tiny motor balloon was by far the best -in design of any that appeared during the first century of aëronautics. -It may be regarded as the harbinger of the swiftest modern French -balloons. It was also an inspiration to Henri Giffard who assisted -Jullien in constructing his clever model, and shortly afterwards built -the first dirigible ever driven by a heat engine. - -The illustrious Henri Giffard was perhaps the first aëronautical -engineer adequately endowed and circumstanced to realize, on a -practical scale, General Meusnier’s well pondered and truly scientific -plans for a motor balloon. He had studied in the college of Bourbon, -and had worked in the railroad shops of the Paris and St. Germain -railway. He had further equipped himself by making free balloon -ascensions, under the auspices of Eugene Godard, for the purpose of -studying the atmosphere; and by building light engines, one of which -weighed 100 pounds, and developed three horse power. Finally in 1851 he -patented an air ship, consisting of an elongated bag and car, propelled -by a screw driven by a steam engine. He had not the means to build such -a vessel, but he had the genius and training necessary to construct it, -and at the same time enough enthusiasm and persuasive power to induce -his friends, David and Sciama, to loan him the requisite funds. - -[Illustration: FIG. 18.—GIFFARD’S STEAM DIRIGIBLE, 1852.] - -Giffard’s first dirigible was successful in both design and operation. -It consisted of a spindle-shaped bag covered with a net whose cords -were drawn down and attached to a horizontal pole, from which the car -and motor were suspended, and at the end of which was a triangular -sail serving as a rudder. To guard against fire, the furnace of the -vertical coke-burning boiler was shielded by wire gauze, like a miner’s -lamp, and the draft, taken from its top through a downward pointing -smoke pipe, was ejected below the car by force of exhaust steam, from -the engine, thus obviating, as Giffard asserted, all danger from the -use of fire near an inflammable gas. The car hung twenty feet below -the suspension pole, and carried a three horse-power engine driving a -three-blade propeller 11 feet in diameter, making 110 turns a minute. -The motor complete, including the engine and boiler without supplies, -weighed 110 pounds per horse power. The bag measured 143 feet long, 39 -feet in diameter, and 75,000 cubic feet in volume. Giffard reports of -his first voyage, made from the Hippodrome in Paris at five fifteen -o’clock, September 23, 1852, that although he could not sail directly -against the strong wind then blowing, he could attain a speed of six -to ten feet per second relatively to the air, and he could easily -guide the vessel by turning her rudder. He continued his journey till -nightfall, then made a good landing, near Trappes, and by ten o’clock -was back in Paris. - -This vessel was but a prelude to mightier projects. After some further -experience with dirigibles of moderate size, Giffard designed a -colossal air ship calculated for a speed of forty-four miles an hour. -Its hull was to be of torpedo shape, measuring 2,000 feet in length, -100 feet in diameter, and 7,000,000 cubic feet in volume. It was a -most audacious project, one worthy of the genius and energy of that -illustrious engineer, the most original and daring inventor known in -the aëronautical world during the nineteenth century. - -Stimulated by this huge enterprise, Giffard’s first step was to pay his -debts and make a fortune. He soon acquired a hundred thousand francs -from the sale of small high-speed engines of his own construction, and -with this, settled his account with David and Sciama. Next he realized -several million francs from his world-famous injector, a device by -which steam flowing from a boiler is made to drive in feed-water -against the same pressure. - -He now made definite plans to build a motor balloon of one and a half -million cubic feet capacity, driven by a condensing engine drawing -steam from two boilers, one fired with oil, the other with gas from -the balloon, so as to keep the vessel from rising with loss of weight. -His designs were complete, and everything was provided for. He had -deposited a million francs in the Bank of Paris to defray the estimated -cost. But, in the words of Tissandier,[10] “above the human will and -foresight are the fatal laws of destiny to which the strongest must -submit.” The great inventor was visited with a painful affliction -of the eyes; his sight waned, unfitting him for work; he became -disconsolate, pined away with pain and grief, and in 1882 ended his -life by taking chloroform. - -Giffard was succeeded in France, first by Dupuy de Lome; then by -Gaston Tissandier, well-meaning projectors of steerable balloons, but -too cautious to effect an important advance in the art. The first of -these gentlemen, an eminent marine engineer, in 1872, completed a gas -balloon for the French government, resembling the one designed by -General Meusnier in 1784, and like that also driven by muscular power -actuating a screw, and kept rigidly inflated by use of an internal -balloon, or ballonet. The car was suspended from the bag by a close -fitting cover instead of a net, in order to lessen the resistance, and -it was kept in alignment by use of crossed suspension cords. A speed -of but six miles an hour was attained by the industrious work of eight -men operating an ample screw propeller. A decade later Tissandier, with -a balloon of like design, but driven by the power of an electric motor -and bichromate of potash battery, attained a speed of six to eight -miles an hour. - -[Illustration: FIG. 19.—DUPUY DE LOME’S DIRIGIBLE, 1872.] - -The two vessels were safe but of no practical value, for lack of -sufficient power to cope with the wind. Their motors were fundamentally -unadapted to the purpose of swift propulsion, and incapable of -development to very great lightness and strength. Furthermore, the -vessels themselves were unsuitably designed for speed; their shape -being one of too much resistance, and their dynamic balance being -that of a pendulum, or clumsy parachute, rather than that of a vessel -adapted to cleave the air with celerity, grace and steadiness. If there -had been danger of fire from placing the motor and screw near the gas -bag, that might justify or excuse the clumsiness of design in the craft -of De Lome and of Gaston Tissandier; but, having perfectly safe motors, -it is astonishing that they did not place the center of mass and the -line of thrust more nearly in the line of resistance. This obvious -requirement was duly recognized by several of their contemporaries, -notably by Hänlein in Germany, and by Captain Renard of the French War -Department, and had been observed by Jullien. - -Captain Charles Renard proved to be a worthy inheritor of the dreams, -experience and inventions of the first century of aëronautical -votaries. He did not, indeed, have the picturesque madness displayed -by some of his predecessors; he did not project schemes of marvelous -originality or boldness; but he manifested uncommonly good judgment -and excellent scientific method in combining the researches and -contrivances of others with those of himself and his collaborator, -Captain Krebs. As a consequence they produced the first man-carrying -dirigible that ever returned against the wind to its starting point, -and the first aërial vessel whose shape and dynamic adjustment even -approximated the requirements of steady and swift navigation in a -surrounding medium presenting various conditions of turbulence or calm. -Captain Renard had been studying and designing dirigibles since 1878 -in coöperation with Captain La Haye and Colonel Laussedat, president -of an aëronautic commission appointed by the Minister of War; and had -endeavored to secure from the latter an appropriation sufficient to -construct a dirigible; but his request was at first denied, owing -to the waste of funds on similar projects in 1870. However, with the -help of Gambetta, who promised a sum of $40,000, Renard was enabled to -proceed. In the meantime he had been made director of the laboratory at -Chalais Meudon, seconded by Captain Krebs. - -[Illustration: FIG. 20.—RENARD’S DIRIGIBLE, _La France_, 1884.] - -These officers first worked out the separate elements in the design of -their motor balloon before proceeding to build on a practical scale. -They chose the torpedo form for their gas bag, thereby ensuring in -the hull itself, projectile stability, and diminution of resistance. -They placed the car near the envelope, thus minimizing the disturbing -moment of the screw thrust, and the resistance of the suspension cords. -They employed an extraordinarily powerful electric motor actuating a -large screw so as to obtain a strong thrust with the least effort. -In addition they adopted the best ideas of their predecessors in -aëronautical design; the internal ballonet of Meusnier, and the -close fitting cover of De Lome, with crossed suspension cords. But -unfortunately they used an electric motor instead of some light engine. -Finally, having carefully computed its requisite dimensions, they -proceeded to construct the elegant air ship, _La France_, which was -tested in 1884 and aroused anew the hope of ultimately conquering the -air. - -Further details of this successful ship are of interest. Its hull -was 165 feet long, 27.5 feet in greatest diameter, at one fourth the -distance from its front end, and cubed 66,000 feet, thus having a -buoyancy of two long tons. It was kept rigid under varying conditions, -by means of a ballonet filled with air driven in by a common fan blower -coupled to the motor. Beneath the envelope, a long narrow rectangular -car made of bamboo, covered with silk, was suspended from the cords -of the balloon cover which embraced the hull throughout nearly its -entire length. The car was 108 feet long and 6 to 7 feet across, -carried at its forward end the propeller, at its rear a rectangular -rudder, and between them the aëronauts and the batteries and electric -motor. A sliding weight was used to alter the poise of the ship, and a -guide-rope to soften its descent. - -The electric motor and battery which furnished the propulsive power -were designed expressly for such use, and were considered at the time -to be remarkably light and effective. The motor, which was designed -with the assistance of M. Gramme, weighed 220.5 pounds, and developed -nine horse power. The battery, composed of chlorochromic cells, was the -result of the researches of Renard himself. Having made a careful study -of the best geometrical arrangement of the parts of the cell, Renard -found that this battery would deliver to the shaft one horse power for -each eighty-eight pounds of its weight. Thus the power plant rivaled -in lightness the steam engine of Giffard, and at the same time was free -from danger; but apparently it could not be much reduced in weight, -whereas Giffard’s steam-power plant could be reduced tenfold, as shown -by Renard’s contemporaries. - -The trials of _La France_ in 1884-85 were most successful and -encouraging; not that they represented or pointed to the complete -mastery of aërial navigation, but because they so far surpassed all -previous achievements. The vessel moved through the air as steadily as -a boat on the water, and obeyed her rudder perfectly, heading against -the wind, or at any angle to it, or turning entirely about, at the will -of the aëronauts. On her first voyage from Chalais, August 9, 1884, she -traversed a distance of four and one half miles in twenty minutes, made -various evolutions in the air with the greatest ease, and returned to -her point of departure. The following account of this voyage is given -by Renard: - - “As soon as we had reached the top of the wooded plateaus which - surround the valley of Chalais, we started the screw, and had - the satisfaction of seeing the balloon immediately obey it and - readily follow every turn of the rudder. We felt that we were - absolutely masters of our own movements, and that we could - traverse the atmosphere in any direction as easily as a steam - launch could make its evolutions on a calm lake. After having - accomplished our purpose, we turned our head toward the point - of departure and we soon saw it approaching it. The walls of - the park of Chalais were passed anew, and our landing appeared - at our feet, about 1,000 feet below the car. The screw was - then slowed down, and a pull at the safety-valve started the - descent, during which, by means of the propeller and rudder, - the balloon was maintained directly over the point where our - assistants awaited us. Everything occurred according to our - plan, and the car was soon resting quietly on the lawn.” - -Six other similar voyages were made within the two years following, -and we have as a result, that in five out of the seven trials, the -balloon returned to its point of departure. Its failure to return in -the other two trials was due, in the one case, to the breaking down of -the motor; in the other, to the resistance of a strong wind which made -it necessary to land at a distance from the starting point. The last of -these remarkable voyages was performed in presence of the Minister of -War, on September 23, 1885. The balloon started from Calais and sailed -against the wind directly to Paris, passed over the fortifications, -described a graceful curve and returned to its place of departure, -recording an average speed of 14.5 miles an hour. - -The torpedo form of hull, chosen by Renard and Krebs, has two important -advantages; one is projectile stability, the other is economy of -propulsive power. Owing to the blunt bow and long tapering stern, the -center of mass is well forward, while the center of side wind pressure -is more to the rear. As a consequence, if the vessel should encounter a -quartering wind-gust, or have her nose slightly turned from the course, -she would promptly right herself like a dart or an arrow. If on the -contrary, the hull were a symmetrical spindle, the vessel would move -forward in unstable equilibrium, and, once slightly diverted from her -course, would tend to deviate further, like an arrow with unloaded head. - -The second advantage mentioned is also worth attention, viz.: that at -ordinary transportation speeds a longish spindle has less resistance -with a blunt bow than with a very sharp one. Renard and Krebs did -not account for this fact; but the present writer, by determining -separately the skin friction and the impactual resistance of the air, -proved that in sharpening the bow beyond a certain best form, its -friction increases faster than its head resistance diminishes, the -most suitable shape being that of a torpedo whose nose has a radius -of curvature of about two diameters, and its stern a radius of about -twelve diameters. - -While the successors of Giffard in France were thus engaged in -developing dirigibles driven by muscular or electric power, a few -German experimenters were applying gas and benzine engines to such -vessels, with better promise of ultimate practical success and -usefulness. The first of these was Hänlein, who in 1872 advanced the -meritorious project of driving a well shaped balloon by means of a gas -engine taking its fuel from inside the balloon, and making good the -loss by pumping air into the ballonet. This balloon was of far better -design for swiftness and kinetic stability than the contemporary one of -Dupuy de Lome. Its hull was a well pointed cylinder 164 feet long, 30 -feet in diameter and of 85,000 cubic feet capacity, made air-tight by -a thick coating of rubber inside, and a thin one outside. The car was -rigidly suspended near the envelope and carried a 6 horse-power Lenoir -gas engine actuating a large screw. Notwithstanding that the buoyancy -was small, owing to the use of coal gas, this air ship attained a speed -of 15 feet per second. By employing hydrogen, a much larger engine -could have been carried, entailing a much swifter speed. During its -trial the balloon was kept near the earth’s surface, held loosely by -ropes in the hands of soldiers. The air ship was remarkably successful -for that early date, and had the potency of greater achievement -than its contemporaries in France; but owing to lack of funds its -capabilities were not fully developed. If it had been inflated with -hydrogen, and propelled by use of gas and petrol, so that the loss -of weight would compensate for the loss of buoyancy, it might have -anticipated the speed and endurance of the best air ships built toward -the close of the nineteenth century, or later. - -PLATE II. - -[Illustration: HAENLEIN’S GAS-DRIVEN DIRIGIBLE.] - -[Illustration: WÖLFERT’S BENZINE-DRIVEN DIRIGIBLE.] - -[Illustration: SANTOS-DUMONT’S DIRIGIBLE, _NO. 16_. - -_Photo E. Levick, N. Y._ ] - -In 1879, Baumgarten and Wölfert in Germany built a dirigible equipped -with a Daimler benzine motor, but otherwise not possessing any special -merit. An ascension was made at Leipsic in 1880, but owing to improper -load distribution the vessel reared on end and crashed to earth. After -further experiments, an ascension was made on the Templehofer field, -near Berlin, in 1897, but this ended disastrously; for the benzine -vapor ignited; the fire spread to the balloon, and the vessel fell -flaming to the earth, killing Wölfert and his assistant. Baumgarten had -died some years before. - -In 1897, an aluminum air ship invented by an Austrian engineer, named -Schwartz, was launched on the Templehofer field. Its hull was of -cylindrical form with conical ends, made of sheets 0.008 thick, and -stiffened with an internal frame of aluminum tubes. Being leaky and -inadequately driven, it voyaged but four miles, drifting with the wind, -then fell to earth with considerable shock. The pilot, a soldier of the -Balloon Corps, escaped by jumping, before the vessel struck ground, but -the frail unbending hull was soon demolished by the buffeting of the -winds as it lay stranded on the unyielding earth. This was the second -air ship built after the plans of poor Schwartz, the first having -collapsed on inflation. He had, however, the credit of being the first -to drive a rigid air ship with a petrol motor, and thus to inaugurate -a system of aërial navigation capable of immense development, in -the hands of sufficient capital and constructive skill. Thus the -rigid type, conceived and crudely tried by Marey Monge and Dupuis -Delcourt in the early part of the century, began to approach practical -realization toward the end of the century. - -The process of inflating with hydrogen such a rigid hull is -interesting. Schwartz’s plan, carried out by Captain Von Sigsfeld, -was to place the hydrogen in one or more sacs inside the hull, thus -expelling the air and filling the space, then withdrawing the sacs and -leaving the hydrogen within. A better plan is to have a single sac -inflated with air just filling the hull like the lining of an egg, then -to force the gas between the lining and metal wall of the hull, thus -expelling the air from the sac, which when completely collapsed can be -removed. Practically the same result can be obtained by use of a thin -fabric covering one half the inner wall, like the lining of an egg. -Further provision can easily be made for manipulating the ballonet in -such a case. - - - - - CHAPTER IV - - INTRODUCTION OF GASOLINE-DRIVEN DIRIGIBLES - - -We have now traced the art of balloon guidance and propulsion from its -earliest inception to the close of the nineteenth century. It was a -period of extravagant hope and chimerical scheming, but withal a period -fruitful in devices of fundamental value. The best experiments paid no -dividends, but they prepared the way for really useful vessels. The -methods of manipulation and control had been sufficiently developed -to answer immediate needs. The air ship was at least dirigible, if -not practical. It kept its shape, obeyed its rudder, rose and fell -according to the operator’s will. It was, however, a fair-weather -machine, beautiful in appearance, but helpless in any considerable -wind. Speed was now the desideratum, and the attainment of this -involved new difficulties. The storm-proof balloon was still a dream. - -Naturally one inquires what velocity makes a dirigible air ship really -practical, assuming all other requirements satisfied. The minimum -allowable speed depends largely upon the locality and season. On Long -Island an assured velocity of forty to fifty miles an hour would -seem desirable; for there the winds are swift and the water near. In -Washington, or Berlin, thirty miles an hour is enough, though each -additional mile per hour must be regarded as a considerable gain on -a small margin of progress in facing a stiff breeze. Colonel Renard -has estimated, from a study of the wind records near Paris, that a -dirigible is practically useful in that locality if it can maintain a -speed of twenty-eight miles an hour for ten or twelve hours; since in -that case it can maneuver 81 days in 100. - -Renard’s own graceful ship attained a speed of but half that much. In -order, therefore, to give his vessel the desired usefulness its speed -must be doubled. This would require an eightfold[11] increase of motive -power without increase of weight. Evidently then the cardinal requisite -was a light durable motor of extraordinary output. Such motors -fortunately were now coming into the market, owing to the development -of gasoline engines for automobile racing. - -The year 1898 witnessed the commencement of two famous systems of -navigation by the lighter than air, one in France, the other in -Germany, destined quickly to revolutionize the art, and to establish -it on a practical basis. The leading exponents of these two systems -were Señor Don Alberto Santos-Dumont, a rich young Brazilian living in -Paris, and Count Ferdinand von Zeppelin, Germany’s stanch old admiral -of the air. Both achieved success by applying the gasoline engine to -the propulsion of elongated balloons, but by very different methods. -Santos-Dumont, apparently ignoring, or fearing to adopt, the excellent -hull and car designed and used by Renard, began where Tissandier left -off, with a symmetrical hull and low-hung car, thus producing a safe -aërial pendulum, if not a racing machine; then by degrees he gradually -felt his way to something more efficient. Zeppelin began with a long -cylindrical hull pointed at the ends, rigidly framed like that of -Schwartz, and supporting its car and propellers well aloft near the -line of resistance. His was a bold and effective design but difficult -to execute. Santos-Dumont scored the first success, and startled the -world by his spectacular flights; but ere long he was surpassed by -other builders of non-rigid balloons. Zeppelin won his success slowly -and by heroic perseverance in the face of enormous obstacles, finally -emerging as the most successful and illustrious figure in the history -of aëronautics. The achievements of these two pioneers and colleagues -make the first decade of the twentieth century memorable in the annals -of aërial navigation. - -Santos-Dumont, who spent his early years on his father’s large coffee -plantation in Brazil, had, during boyhood, dreamed of navigating the -air, and in 1897, at the age of twenty-four, made in France his first -ascension in a spherical balloon. While living at Paris during that -year he gave much time to motorcycling, automobiling and operating -spherical balloons, of which he possessed two constructed after his own -ideas; one, the smallest in the world, designed for solitary voyages, -the other large enough for more than one person, intended for social -excursions. Thus by way of amusement, and probably by impulse rather -than deliberate purpose, he was equipping himself to become both the -designer and the pilot of his future dirigibles. - -Having acquired experience and skill in operating both balloons and -engines, the young enthusiast set about realizing his boyhood dream -of navigating the air independently of the course of the wind. His -first dirigible was designed to carry his weight of 110 pounds and a -3½ horse-power petroleum engine taken from his tricycle, and reduced -in weight to 66 pounds. The hull was a cylinder of varnished Japanese -silk, 82½ feet long including its pointed ends, 11½ feet in diameter -and 6,354 cubic feet in gas capacity. A ballonet, or air pocket, -occupied the lower middle of the envelope. The basket for the little -pilot, engine, and two-blade propeller was suspended far below the -hull, to which its cords were attached by means of small wooden rods -inserted into hems along each side of the envelope, for a great part of -its length. The poise of the vessel was controlled by shifting weights -fore and aft, while the turning right and left was effected by means -of a silk rudder stretched over a steel frame. On the whole it was a -crude and primitive affair, but of considerable interest as the first -dirigible of a young man destined to give a strong impulse to the -development of motor balloons of the non-rigid type. - -After some preliminary tests, the little air ship and pilot soared away -from the Zoölogical Garden in Paris, on September 20, 1898, rising in -the face of a gentle wind, to the wonder and delight of a large crowd -of witnesses, some of them professional aëronauts and very skeptical -as to the outcome of this venturesome experiment. The ship maneuvered -round and round overhead of the applauding throng, steering readily in -all directions. Then the green navigator ascended a quarter of a mile -and merrily continued his evolutions in the direction of the Longchamps -race course. But when he wished to descend he observed the envelope -contracting in volume, and was appalled to find that he could not -pump air into the ballonet fast enough to keep the hull distended. It -became swaybacked, and “all at once began to fold in the middle like a -pocket-knife; the tension cords became unequal and the balloon envelope -was on the point of being torn by them.” As he was falling swiftly -toward the grassy turf at Bagatelle, he called to some boys who were -flying kites, to grasp his guide-rope and run against the wind. They -understood and ran so swiftly with the canted balloon that it played -kite, and descended with a moderated fall, landing the frightened -aëronaut safely on the turf. - -Except for the doubling of his long balloon, Santos-Dumont’s first -voyage was satisfactory, and he returned to Paris elated. He had found -it easy to steer in all directions. He could change his level hundreds -of feet without discharge of gas or ballast, by merely canting his -balloon, and allowing it to run obliquely up or down grade. He had -stemmed the wind and gone whither he pleased, at such speed as to make -his clothes flutter. And best of all he had found no danger in using a -gasoline motor near an inflammable gas bag. The mere buckling of the -long bag was a trifle, to be remedied by using an air pump adequate to -maintain the flabby thing well inflated. He felt, therefore, that he -had the conquest of the air well in hand, and that he was drifting into -air ship construction as a life work. Small wonder that he continued -his conquests till he had built, in less than one decade, fourteen -motor balloons. - -_Santos-Dumont No. 2_ was closely patterned after its predecessor, -but was a little larger and carried a rotary fan worked by the motor, -to keep the balloon plump by filling the air pocket, or ballonet. On -May 11, 1899, an ascension was made from the old starting place, but -in rainy weather. As the vessel rose its hull contracted faster than -air could be pumped into the ballonet, the long bag doubled worse than -before, and dropped into the trees with its chagrined but fearless -rider. - -The _No. 3_, which followed, was a short, thick vessel, 66 feet long -by 25 feet in diameter, having in outward appearance the features of -Dupuy de Lome’s very stable and very slow dirigible. It was apparently -a safety ship for a scared young man who had not yet learned fully to -appreciate Renard’s elegant design. It served for a few pleasant trips, -while the inventor was screwing up courage to build another cylindrical -vessel, and gradually realizing the advantage of an elongated car such -as Renard had employed in _La France_. Not only was the hull short -and thick, but it was further secured from buckling by a horizontal -stiffening pole placed between it and the basket, and from which the -latter was hung. After some voyages in _No. 3_, which the captain found -very tractable, and probably capable of fifteen miles per hour, he was -ready to begin a new vessel. - -The _No. 4_ was a compromise between the better features of _No. 3_ -and its predecessors. The elongated hull and ballonet were resumed, -and the stiffening pole was elaborated into a longish car resembling -Renard’s, but of triangular cross section. On this long trussed frame -were placed the motor, propeller, rudder and the rider in his basket. -A seven horse-power engine turning, at one hundred revolutions per -minute, a screw propeller having two blades, each 13 feet across, gave -a thrust of 66 pounds. Frequent trials of the ship during the summer -of 1900, in presence of the Exposition crowds, brought the inventor -into extraordinary prominence, and secured for him the “Encouragement -Prize” of the Paris Aëro Club, consisting of the yearly interest on -one hundred thousand francs, this being one of M. Deutsch’s numerous -foundations for the promotion of aëronautics. - -In the spring of 1900, M. Deutsch de la Meurthe had established another -prize which Santos-Dumont now greatly coveted, and hoped ere long to -win. This was a cash sum of one hundred thousand francs to be awarded -by the Scientific Commission of the Aëro Club of France to the first -dirigible that, between May 1 and October 1, 1900, 1901, 1902, 1903, -1904, should voyage from Saint Cloud to and around the Eiffel tower, -and return within half an hour. The distance to the tower and back, -not counting the turn, was nearly seven miles, and the estimated speed -required to fulfill the conditions for winning the prize, even in calm -weather, was 15½ miles per hour. - -As Santos-Dumont thought his _No. 4_ scarcely swift enough to win -the Deutsch prize, he enlarged it by inserting an additional length -of sixteen feet at its middle, supplied it with a stronger car, and -applied a larger engine, naming the new vessel so formed, his _No. -5_. Its hull was 109 feet long, 17 feet in largest diameter and cubed -nearly 20,000 feet. A four cylinder air-cooled petroleum motor driving -a screw propeller having two blades, each 13 feet across, gave a thrust -of 120 pounds, at 140 revolutions per minute, and produced such draft -as to give the inventor pneumonia. Among other novelties water ballast -was used, and piano wires replaced the old-time suspension cords. - -The _No. 5_ proved so powerful and swift that on July 13, 1901, -Santos-Dumont attempted to win the Deutsch prize. Starting from the -Aëro Club grounds at Saint-Cloud in presence of official witnesses, -at half past six in the morning, when the air is usually stillest, -he turned the Eiffel Tower in the tenth minute, thus gaining twenty -minutes for the home stretch. But on his return he encountered an -unexpected head wind, and after a terrific struggle reached the -timekeepers at Saint-Cloud in the fortieth minute. - -To add to the romance of this voyage, the genii of the upper elements -stopped his motor, shortly after his return, and the bold sailor in his -shining ship landed in a stately chestnut tree very near the house -of the Princess Isabel, daughter of Dom Pedro. She very thoughtfully -arranged a breakfast for him and sent it up in a basket, where he was -at work disengaging the balloon, at the same time inviting him to call -and relate to her the story of his voyage. A few days later she sent -him a medal of St. Benedict “that protects against accidents.” He wore -the medal, and on his very next trial escaped without a scratch from an -appalling accident which might have terminated fatally. He continued to -wear the gift of that gracious princess, on a thin gold chain circling -his wrist, and many a time thereafter endured unscathed the most -dreadful accidents, as if he possessed a charmed life. - -On August 8, 1901, the dauntless aëronaut again sailed for the coveted -prize, at the same still morning hour, sacred to duels and aërial -contests. In nine minutes he turned the tower and headed bravely for -home. But soon a leaky valve let the balloon shrink and the wires -sag into the whirring propeller, which therefore had to be stopped. -Santos-Dumont now had the choice of drifting back against the tower -and destroying his vessel high in air, or of descending at once, by -allowing the balloon to sink without discharge of ballast. He chose -the latter course, hoping to land on the Seine embankment; but instead -his balloon struck the top of the Trocadero hotel, exploded and fell -in fluttering shreds into the courtyard. Some firemen who had been -watching the flight from a distance, came with a rope and found -the long car leaning like a ladder against the wall of the court, -the balloon shreds hanging from it in graceful folds, and Captain -Santos-Dumont perched aloft in his wicker basket wearily waiting for -St. Benedict’s further aid. As usual, he was rescued intact. - -On the evening of his fall on the roof of the hotel Santos-Dumont -issued specifications for his famous _No. 6_, which surpassed -all its predecessors in safety and speed. It had the shape of an -elongated ellipsoid with pointed ends, measured 110 feet in length, -20 feet in major diameter, 22,239 cubic feet in volume, and had an -absolute ascensional force of 1,518 pounds. It was driven by a twelve -horse-power four-cylinder water-cooled engine which gave the propeller -a thrust of 145 pounds. To insure against buckling of the gas bag, an -air pump connected with the motor, kept the ballonet under constant -pressure, regulated by an escape valve through which the excess of -air passed outward. To secure the envelope against rupture, due to -the expansion of the hydrogen at unusual elevations, a stronger valve -was used to let the gas escape from the envelope into the atmosphere. -Thus the air escape valve kept the pressure constant in the partially -distended ballonet, and consequently also in the surrounding gas -envelope itself; while the stronger gas valve in the envelope opened -only in an emergency, when the gas pressure had fully collapsed the -internal air pocket and was threatening to explode the envelope. With -all its improvements this new vessel was finished and inflated by -August 4, being a work of twenty-two days, and after some preliminary -trials was ready to try for the Deutsch prize. - -The day of triumph followed quickly. On October 19, 1901, at 2.45 -P.M., Santos-Dumont again headed for the Eiffel Tower in presence of -the official witnesses. In spite of a wind of six meters per second -striking him sidewise, he held his course straight for the goal, and -turned it in the ninth minute, as in his preceding attempt. On the -return he had to struggle against a quartering wind and the caprice -of his motor, which sometimes threatened to stop, and again spurted -so actively as to turn the ship upward at a steep angle. The mighty -throng below, in the Auteuil race track and the Bois de Boulogne, sent -up immense applause, then suddenly held its breath in alarm, as the -vessel pitched violently. But the hardy little rider was self-possessed -and at home on his vaulting Pegasus. Alert to every prank he held his -course straight for the timekeepers and passed over their heads at -exactly twenty-nine and one-half minutes after starting. - -His unmercenary disposal of the two rich awards which he had won seemed -no less commendable than the dauntless industry which achieved such -rapid success. The Deutsch prize amounting in all to one hundred and -twenty-five thousand francs he divided into two unequal parts. The -greater sum of seventy-five thousand francs he gave to the prefect -of police of Paris, to be used for the deserving poor; the remainder -he distributed among his employés. The Encouragement Prize of four -thousand francs a year, mentioned before, he also declined to retain, -but instead he founded with the money a new prize at the disposal of -the Aëro Club. As a second reward for his triumphal voyage around the -Eiffel Tower, he received from the Brazilian government one hundred -and twenty-five thousand francs and a beautiful gold medal bearing -appropriate and very complimentary inscriptions. - -Now that the stimulus and excitement of striving for the Deutsch prize -was over, the ardent inventor was free to develop and test his air -ships in a deliberate and scientific manner. He therefore set about -building specialized types of motor balloons, and practicing with them -over all kinds of territory, smooth and rough. Within the next six -years he constructed eight more air ships making altogether fourteen, -besides his various free balloons, to say nothing of the aëroplanes and -hydroplanes which he found time to develop. But before indulging in -these new luxuries he would have more experience with his _No. 6_. - -When the cold weather set in, following his victorious flight about -the Eiffel Tower, Santos-Dumont went with his _No. 6_ to Monaco, to -practice air cruising over the Mediterranean. The Prince of Monaco -had erected for him an “aërodrome,” or balloon shed, facing the sea -and very near shore. On pleasant days the daring pilot would cruise -up and down the bay, not far from shore, trailing his guide-rope over -the waves with the greatest ease, and to the applause of thousands of -spectators. But on February 14, 1902, he set forth on a pleasure cruise -over the bay with insufficient gas pressure, and thus came to grief. -The bag grew flabby; the hydrogen poured to its higher end; the vessel -reared up so steeply that the propeller had to be stopped to avoid -its cutting the envelope. Rather than drift at the mercy of the wind, -the pilot opened the valve and sank slowly to the water where he was -rescued by a boat. On the following day the parts of his _No. 6_ were -fished out of the sea and sent back to Paris. His few days’ practice -had taught him the delights of guide-roping over the waters, and his -accident induced him in future to sew unvarnished silk partitions -across his balloons, to prevent the hydrogen passing too suddenly from -one end to the other. - -Returning to Paris he built for himself an “aërodrome,” provided -with great sliding doors like the one at Monaco, and equipped with a -hydrogen plant, constructive appliances, and everything needed for -the rapid rebuilding or repair of air ships. It stood in a vacant lot -surrounded by a high stone wall and was made of posts covered with red -and white canvas, so that it looked like a great striped tent. Inside, -the central stalls were 31 feet wide, 165 feet long, and 44½ feet -high,[12] the whole enclosure having accommodation for seven dirigibles -all inflated and ready for instant service. When completed, in the -spring of 1903, it was at once used to harbor three new air ships. -These were the _No. 7_, designed for racing contests; the _No. 9_, -called the Runabout, a minim air ship used for calls and short pleasure -trips; and the _No. 10_, called the Omnibus, intended for several -persons, with ample supplies for a considerable journey. - -The _No. 7_, which excelled its predecessors in length and bulk, was -intended greatly to outstrip the best of them in velocity. The first -air ship had attained fourteen miles per hour, the _No. 6_, nearly -twenty miles an hour in winning the Deutsch prize, and over twenty -miles per hour on subsequent occasions, though provided with a motor -rated at only 12 horse power. The new vessel which had little greater -resistance than _No. 6_, was to carry four times the internal pressure, -or about 12 centimeters of water, and to be propelled by an engine of -60 horse power. The inventor expected therefore to attain a speed of -between forty and fifty miles per hour. A very lofty expectation for -that day, and one still unrealized for many years. - -The racing air ship, or _No. 7_, was of cigar form, supporting a long -car beneath, and generally resembling the _No. 6_, but slightly more -tapering. Her length was six times her major diameter, and her volume -45,000 cubic feet. The envelope was made of two layers of the strongest -French silk, four times varnished, and was built exceptionally thick -at the stern, where the differential outward pressure is greatest in -flight. The propulsion was effected by a 60 horse-power water-cooled -four-cylinder Clément engine actuating two screw propellers 16½ feet -in diameter, one in front the other at the rear of the car. The poise -and maneuvering were to be controlled in the usual way, by means of the -rudder and shifting weight. The inventor seemed not to realize that -the bow of his vessel was too sharp to cleave the air with minimum -resistance, though his predecessor, Jullien, in 1850, had discovered -experimentally that a torpedo form is better for speed than the -symmetrical spindle form used by Santos-Dumont in his racing vessel. He -did, however, in time, learn that the torpedo form of hull is better -for stability of forward motion, and hence adopted that form in his -little _Runabout_. - -The _No. 9_ was a thick torpedo-shaped air ship originally cubing only -7,770 feet, though later enlarged to 9,218 feet. It was so thick as -to appear nearly egg-shaped. In order to make it respond promptly to -the rudder Santos-Dumont drove it through the air blunt end foremost, -but with apparent regrets, thinking that it would cleave the air -more easily than sharp end foremost. In this he was mistaken; for -the writer has shown that a body of such shape encounters much more -resistance—roughly one hundred per cent more—when driven sharp end -foremost than when driven blunt end forward. This fact furnishes one -reason why most whales and swift fishes have blunt bows and long -tapering sterns. However this be, the practical man felt his way to -success, whether right or wrong in his theory of resistance. When -actuated by a three horse-power Clément motor, weighing 26½ pounds, the -little air ship carried its jaunty pilot twelve to fifteen miles an -hour on many a merry trip about Paris and its environs. - -The _No. 10_, or _Omnibus_, was a well shaped vessel of nearly eighty -thousand cubic feet capacity, and amply provided with steering -devices. Its hull tapered slightly from front to rear, terminating -in projectile-shaped ends, and had a length of nearly six times its -major diameter. Underneath was suspended a long car provided with -aëroplane surfaces, in addition to the usual rudder, for controlling -its movements. - -Its arrow-like appearance was suggestive of some of the greatest German -balloons of the decade. Indeed, the _Omnibus_, if well powered, might -have proved a very swift vessel, in addition to a powerful carrier. -But she was designed merely for easy going passenger service, for the -purpose of popularizing aëronautics and stimulating its growth. - -Santos-Dumont now had three typical air ships, a spacious and well -equipped “aërodrome,” and ample facilities for advancing the science -of motor balloons on a moderate scale. He could not, however, maintain -the ascendency in this branch of science in France; for he encountered -the rivalry of great wealth employing highly trained engineering and -constructive talent. He could, however, still promote the art as a -pioneer and a popularizer. This he continued to do. With his little -_Runabout_ he would one day guide-rope along the boulevard, another -day take up a little boy, another day send up a beautiful young lady -to navigate the air alone for a short distance, another day voyage -over the military parade grounds and with his revolver fire a salute -of twenty-one shots to the President of France, and give exhibitions -to arouse the interest of the War Department. But he could not keep -pace with the new giants in aëronautics, and he did not attempt -it. Nor did he ever build a vessel of sufficient power, speed and -durability to be purchased by the French nation. That honor went to his -opulent contemporaries who had not failed to take cognizance of his -contributions to the aërial art. - - - - - CHAPTER V - - PRACTICAL DEVELOPMENT OF NON-RIGID DIRIGIBLES - - -In 1899 the Lebaudy brothers, wealthy sugar refiners in Paris, -commissioned their able engineer, Julliot, to make investigations -and develop plans for a large and swift air ship. This he did with -the assistance of Surcouf, a well-known manufacturer of balloons at -Billancourt, Paris. Emulating the example of Santos-Dumont and certain -German aëronauts in making their plan, they adopted the light petroleum -engine for motive power, but experimented on a larger scale, thus -creating a new era in military aëronautics in France. Their first -vessel was the _Jaune_ whose bag was built at Surcouf’s place, and -its mechanical part at the Lebaudy Sugar Refinery. When launched, -in 1902, it so pleased the owners that they determined to continue -the experiments on a larger scale. Their second air ship, called the -_Lebaudy_, after fulfilling various tests, was accepted by the French -government and formed the beginning of its modern aërial fleet. - -Moisson, near Paris, where the balloons were kept, now became quite an -aëronautical center. Here, under military supervision and the skillful -management of the aëronaut Juchmes, other dirigibles were built in -rapid succession. Of these the _Patrie_ was launched in 1906, and the -_République_ in 1908, both fine swift vessels capable of voyaging many -hours and carrying many passengers. The Lebaudy vessels were the first -air ships of the “semi-rigid type,” in which the long and flexible -envelope, or hull, is provided with a rigid keel or floor, from which -the car is suspended with its machinery and passengers. They are, -therefore, of unusual interest both for their scientific design and for -the stimulus they imparted to the growth of aërial fleets. For this -reason they may well be studied in some detail. - -The first Lebaudy air ship, called the _Yellow_, because of its color, -had an envelope constructed of a rubber-treated cotton fabric, made in -Hanover and covered with a yellow coating of lead chromate, to ward off -the sun’s actinic rays from the rubber, and thus prevent deterioration. -Her hull, which was cigar shaped and inflated with hydrogen, measured -183 feet in length, 32 feet in diameter, and 80,000 cubic feet in -volume. She was propelled by a 40-horse-power Daimler motor actuating -twin screws, and attained a maximum speed of twenty-six miles an hour. -During her first year’s service she made many ascensions, returning to -her starting point twenty-eight times out of twenty-nine. Her longest -voyage, made at Moisson, June 24, 1904, was sixty-two miles in two -hours and three quarters, with an average speed of twenty-two miles -an hours. But in November, 1902, while landing in a high wind at the -end of her voyage from Paris to Chalais-Meudon, she was wrecked by -colliding with a tree. Her motor, however, was uninjured, and a new -envelope was at once prepared. - -The second vessel, called the _Lebaudy_, and brought out in 1904, -though resembling her predecessor, had a number of improvements in -detail. Her hull was somewhat larger than the _Jaune_, and no longer -pointed at the stern, but rounded off to an ellipsoidal shape, and -provided, like the rear of an arrow, with guiding, or steadying planes. -It measured 190 feet in length and 94,000 cubic feet in volume. It -was provided with two windows for internal inspection, and had an air -bag of 17,650 cubic feet, divided into three parts. This air bag was -inflated by a rotary fan near the main body, driven by the motor during -flight, and by a storage battery when at rest. Suitable horizontal -and vertical sails were used to steady and guide the vessel; also a -guide-rope and anchor were carried. The car, suspended by steel ropes, -ten feet below the hull, carried the passengers and supplies; also -the motor actuating twin propellers, one on either side. At night an -abundance of light was available, each passenger carrying a small lamp -fastened to his clothes, the car itself bearing a powerful acetylene -projector in its front, and two other lamps of 100 candle power each, -to illumine the vessel. It was an elaborate affair, costing fifty to -sixty thousand dollars, and was the outcome of experiments costing ten -times that sum. - -PLATE III. - -[Illustration: THE _LEBAUDY_. - -_Photo E. Levick, N. Y._] - -[Illustration: _LA PATRIE._ - -(Courtesy E. L. Jones.)] - -[Illustration: LEBAUDY’S _MORNING POST_.] - -The _Lebaudy_, with these various improvements, gave much satisfaction -to her owners, and received favorable recognition from the French War -Department. During the thirty ascensions and voyages of her first -year’s service, she proved herself a swift vessel, easy to control, -very stable, and safe to land on solid ground. The Minister of War, -who had followed her developments with much interest, appointed a -commission to test her value for military service, with a view to her -adoption by the government. The test required that the balloon remain -in active service three months, always being anchored in the open, and -that it perform certain prescribed maneuvers and voyages. In one of -these it sailed with three persons on July 3, 1905, from Moisson to -Meaux, an air-line distance of 57 miles in two hours and thirty-five -minutes, at an average speed of 22 miles an hour, thence to Chalons, -61 miles in three hours and twenty minutes. Here it was anchored to -some trees, but presently was caught in a strong wind, lifted high in -the air, then dashed violently against other trees, with the complete -destruction of its envelope. Within eleven weeks it was repaired -in the military riding school at Toul, nearby; then, after some -evolutions, returned to its harbor at Moisson. Other maneuvers were -made subsequently, in which five officers were carried at one time, -and interesting experiments were tried, such as dropping a sand bag -upon a given spot, photographing fortifications, etc. The Minister of -War, accompanied by two officers and other passengers, made a trip on -October 24th, which was the seventy-sixth voyage of this stanch vessel. -On November 10th, the hard-worked and successful air ship went into -winter quarters, being now the property of the French government, and -the first of her modern aërial cruisers. - -The _Patrie_ and the _République_, planned on the general lines -of the _Lebaudy_, but in ascending scale of magnitude, were built -expressly for the French government, and experienced brilliant if -ill-fated careers. Both vessels had whale-shaped hulls, with rather -sharp-pointed noses and rounding sterns. The original volume of the -_Patrie_ was 111,250 cubic feet, which was later increased to 128,910, -by the insertion of a cylindrical section at the major diameter of the -hull. The _République_ had a volume of 2,000 cubic feet more than the -_Patrie_, and a length of 200 feet, or a little less than the enlarged -_Patrie_. She also had a diameter of 35½ feet as against 33¾ in the -sister vessel. As the technical reader may like more complete details -of these two noted air ships, a fuller account is given in Appendix III. - -The _Patrie_ was a swift and graceful ship which, during its brief -activities in 1906-7, made many remarkable trips at an altitude of -about half a mile, and frequently maneuvered with the troops. She -sailed with excellent stability, had a speed of about 28 miles an hour, -and, with four men, had a radius of action of 280 miles. In November, -1907, carrying four passengers, she voyaged from Paris to Verdun, -on the German frontier, where she was to be stationed. In spite of -a quartering wind, the total distance of 175 miles was traversed in -seven hours and three quarters, or at an average overground speed of -25 miles an hour. But while at Verdun, after some maneuvers, she was -too insecurely anchored to the ground by means of iron stakes. A strong -wind came, tore out the pickets, and overpowered the soldiers, some -two hundred in number, who were trying to hold the vessel. As she was -pulling them along the ground, they were ordered to let go. The huge -ship bounded high into the air, soared across France, England, Wales, -and part of Ireland, then far out over the Atlantic where she vanished, -leaving no trace behind. - -The _République_ also had a brilliant but ephemeral career, from July, -1908, to September, 1909. She surpassed the _Patrie_ not only in bulk -and buoyancy, but also in power and speed. She had an 80-horse-power -motor as against the _Patrie’s_ motor of 60 to 70 horse power. She -could carry eight to nine men, had a speed of about thirty miles an -hour, and a radius of action of 500 miles. She made a number of long -flights and manifested satisfactory steadiness and stability. But on -September 25, 1909, while maneuvering near Paris, one of her propellers -broke and tore a great gash in her envelope. At once, with outrushing -gas and collapsing hull, the great ship fell 500 feet crashing to the -earth, a total wreck, and killing her crew of four officers. This -disaster illustrated forcibly the advantage of the cellular system of -balloon construction, and drew more favorable attention to the rigid -type of air ship cultivated in Germany. - -The famous firm that produced the _République_ brought forth, in -1909, two other fine vessels patterned after it, the _Russie_ and _La -Liberté_, built respectively for Russia and France. The _Russie_ made -her first voyage on May 29th, ascending 600 feet with eight passengers, -and maneuvering under perfect control. After her official trial, -in June, she was sent to St. Petersburg, being the first dirigible -furnished to a foreign government by a private concern. The _Liberté_ -was launched the last week in August and, after various practice and -official tests, was accepted by the French government two months later. -On a notable voyage, made on September 20th, she sailed ten hours with -her Panhard motor constantly working. - -The escape of the _Patrie_ was a loss keenly felt by the French people, -but soon compensated by the generosity of M. Deutsch de la Meurthe. -This liberal patron of aëronautics had a dirigible of excellent design, -whose hull, based on the plans of Colonel Renard, was contrived and -built by E. Surcouf, director of the Astra aëronautic establishment, -along with H. Kapferer, while its other parts were built by Voisin, -both of Billancourt. In September preceding the accident to the -_Patrie_, he had offered the use of his air ship, the _Ville de Paris_, -to his government, which accepted the gift with the understanding that -it was not to be delivered except in case of war or emergency. When, -therefore, in November, 1907, the disaster occurred to the _Patrie_, -M. Deutsch at once placed his dirigible in the hands of the military -authorities. - -[Illustration: FIG. 21.—_La Ville de Paris._] - -The _Ville de Paris_ showed considerable resemblance to her prototype, -the _France_ of 1884, but differed from that elegant vessel in various -important features. Her hull was shaped like a wine bottle with its -thickest end, or bow, brought to a sharp projectile point, and its -other end furnished, like an arrow, with four fixed guiding surfaces -to steady its flight. These guiding surfaces were elongated, finlike, -cylindrical sacs, inflated as shown in the illustration. The hull -measured 200 feet long, 34½ feet in major diameter, 112,847 cubic feet -in volume. Heavy bands of canvas with their edges sewed along the -sides of the balloon served as flaps for the attachment of the cords -suspending the long car beneath. With this long suspension the weight -of the car was more evenly distributed over the envelope than in the -Lebaudy balloons. An interesting improvement in this air ship was the -stabilizing planes, placed above the car, fore and aft, to lift or -depress aëroplanelike, thus enabling the pilot to raise or lower the -vessel, also to alter her trim, or to check her pitching. As might be -expected, her flight was very steady, but as the motor developed only -70 to 75 horse power, her velocity did not exceed twenty-five miles per -hour. In January, 1908, she made a run of 147 miles in seven hours, six -minutes, with an average speed of 21 miles an hour. Further details of -construction are given in Appendix III. - -We now have had examples of the three leading types of motor balloons; -the rigid, the semirigid, the flexible. The rigid type, as exemplified -in the Schwartz and Zeppelin air ships, is characterized by its -solidly trussed hull of invariable size and form to which all other -parts are directly attached. The semirigid type, exemplified in the -Lebaudy vessels, has a flexible hull, generally of woven fabric, with -a trussed floor or platform for its ventral part, from which the car -is suspended. The flexible type, as seen in the _Ville de Paris_, the -_France_, and its predecessors, consists of a flexible hull entirely -devoid of stiffening framework, together with a car, usually quite -long, suspended from the bag directly. These are all of the important -kinds in use at present. A combination of balloon and aëroplane has -been tried by Santos-Dumont, Malecot, and others, but thus far has -not resulted in a very successful and distinct type. Of the many -powerful, swift, and elegant balloons which sprang into being after -the success of the Lebaudy vessels, all could be classified under the -above three types. Neither kind proved preëminently the fittest for -all service, but the semi-rigid and flexible balloons multiplied most -rapidly; partly, no doubt, because of their cheapness and convenience -of management. We may review briefly this new crop of air ships, before -turning to the novel and huge rigid vessels of Count von Zeppelin. - -The _Ville de Paris_ was followed, in 1909, by the _Clément-Bayard_, -a slightly larger vessel of very similar pattern, constructed for the -Russian government for $40,000. It also, like the _Ville de Paris_, -was built by the Astra Society. The most striking feature of this new -balloon was its curious stern with its bulblike steadying surfaces. -These fin surfaces were not flat, as in the _Patrie_, nor cylindrical, -as in the _Ville de Paris_, but of pear form, with the blunt ends -pointing rearward and inflated like the rest of the hull. Apparently -these tail bags were not economical of power, since, as is well -known, a pear shape encounters greater resistance when moving sharp -end forward than when moving blunt end forward. However this be, the -stabilizing force proved very effective. The vessel was driven by a -Clément-Bayard motor of 100 horse power actuating a wooden screw placed -in front of the long car, as in the _France_. A speed of 30 miles an -hour was attainable, and the ship could accommodate eight passengers. -On one occasion it made a round trip from Sartrouville, traversing 125 -miles at an average speed of 27 miles an hour. It was acquired by the -Russian government on August 23, 1909, having on that day completed -its third official test, and satisfied the requirement of rising 1,550 -meters and voyaging two hours at a height of 1,200 meters. Two notable -incidents of that voyage were that the air ship made a new record for -altitude, and on landing was caught by a squall which tore it from the -hands of thirty men, after which, owing to motor failure, it drifted -freely across country, tripped on a willow, and fell into the Seine, -whence it was rescued after considerable pains and labor. - -Other vessels presently built by the Astra Society may be listed, -together with their size in cubic meters, as follows: _Ville de -Bordeaux_, 3,300 m^3;[13] _Ville de Nancy_, 3,300 m^3; _Colonel -Renard_, 4,000 m^3; _España_, 4,000 m^3; _Clément-Bayard II_, 6,500 -m^3; _Transaerienne I_, 6,500 m^3; _Flandre_, 6,500 m^3 (228,579 -cubic feet). These were among the most noted air ships produced in -France toward the close of the first decade of the twentieth century. -On the whole they proved to be swift and stable ships adapted either -for military use, or for exhibitions and sport, and even for regular -transportation of passengers. - -The _Ville de Nancy_ was one of the conspicuous dirigibles of the -summer of 1909. It was constructed primarily for use at the Exposition -at Nancy, and was owned by the Compagnie Générale Transaerienne, an -aërial passenger transportation society organized at Paris, in -March, 1909, with a capital of one million francs. This society planned -to inaugurate an aërial line from Paris to Bordeaux, in 1910, equipped -with other vessels of the Astra construction, more powerful than the -_Ville de Nancy_, and capable of transporting a dozen passengers. - -PLATE IV. - -[Illustration: _LA VILLE DE PARIS._ - -_Photo E. Levick, N. Y._] - -[Illustration: _COLONEL RENARD._ - -_Photo E. Levick, N. Y._] - -The _Ville de Nancy_ was slightly smaller and slightly more powerful -than the _Clément-Bayard I_, besides differing in minor details. It -measured 55 meters in length, 10 meters in greatest diameter, and -cubed 33,000 meters, as against the 35,000 meters of its predecessor. -It was driven by a 100-horse-power Bayard-Clément motor actuating a -Chauvière screw propeller at the front of the car. The car itself was -made of steel tubes covered with fabric, and near the engine with -sheet aluminum. The tail bags were an evident improvement on those of -the previous air ships, being less blunt at the rear, and therefore -less adapted to generate a retarding suction. They were still rather -bulbous, however. - -This splendid vessel made various interesting voyages during the -summer of 1909, the first on June 27th, piloted by Surcouf and -Kapferer, directors of the Astra Society. On July 14th, she maneuvered -at Longchamps, side by side with the _République_, thus contrasting -nicely with the ship designed by Julliot. It was the first time two -dirigibles navigated together in regular maneuver. The _Ville de Nancy_ -was naturally the swifter, having greater power and less bulk than -the other. About the middle of July she sailed from Sartrouville to -Nancy, where she was to sail about the Exposition grounds and make -daily excursions, carrying passengers for 100 francs per trip. These -voyages proved very popular, being the first of their kind, and in -themselves quite attractive. As the vessel was endowed with excellent -stability and had manifested high speed, she was well suited to be the -first regular passenger air ship, and the herald of the aërial liners -projected to cruise between Paris and Bordeaux. - -The _Colonel Renard_ was closely patterned after the _Ville de Nancy_, -but was larger and more powerful. She measured 212 feet in length, -140,000 cubic feet in volume and carried an engine of 120 horse power, -driving a Chauvière propeller. On July 13th she made her first trip, -cruising one hour with notable facility, then reëntered the hangar[14] -of the Astra Society, at Beauval near Meaux. Thence, on August 23d, she -sailed for Rheims to compete in the aëronautical races, arriving after -a very successful cruise. On August 29th, she circled the ten kilometer -rectangular course at Betheny, near Rheims, five times in 1 hour, 19 -minutes, 40 seconds, thus winning the Prix des Aëronats,[15] of 10,000 -francs offered for the vessel that should accomplish, in the least -time, those five rounds, aggregating 50 kilometers. The showing was not -remarkable, but the vessel could sail much faster in a straightaway -voyage. - -The prize-winning _Renard_ was quickly followed by the _España_, a -vessel of the same size and pattern, built for the Spanish government -by the same capable firm. During October this fine air ship made -several trial trips, carrying seven men. On November 2d she made -a splendid official test voyage of five hours, sailing from the -Astra aërodrome, at Beauval, to Paris and return, a distance of 250 -kilometers in 5 hours and 10 minutes, or at the average rate of 31 -miles an hour for the entire course. On November 5th, she started on a -ten-hour voyage, with five men and fuel for fifteen hours; but after -five hours, stopped her engine, and came to earth, owing to the bending -of the main shaft of the motor. - -Besides the great auto balloons designed by Julliot and Surcouf, of -which the _République_ and _Colonel Renard_ are examples, a number of -convenient cruisers were brought forth in 1909 by the Zodiac Company. -One of the leading spirits in this enterprise was the famous Count de -la Vaulx, well known for his auto balloon designs and his long voyages -in sphericles. The chief merit of these modest air ships, which ranged -in volume from 25,000 cubic feet upwards, was cheapness and facility of -demounting and shipment. They were intended to popularize the art among -the masses, by giving everyone a chance to make a voyage at no great -expense. Besides their applicability to sport, touring, and public -uses, some were designed for considerable speed and endurance; which -qualities, together with their demountability and partial independence -of hangars, were expected to give them military value. They were of -the flexible type, so arranged that the various parts were easily -detachable, so as to be packed for transportation, by wagon or car. -The smaller ones might be called semi-navigables, since they had the -organs of a swift motor balloon, but, like the common sphericles, -could easily be demounted and hauled home—a likely issue on a day of -any considerable wind. The first one cost $5,000, cubed 25,000 feet -and, with its 16-horse-power engine, traveled 13 miles per hour. Its -hull had the form of a whale with docked and rounded tail. From this -body hung an elongated car with a screw at the rear and elevating -planes in front. Others of similar make, but larger, followed in rapid -order, their common mission being that advocated by Santos-Dumont, in -the early part of the decade, when he produced his _Runabout_ and -_Omnibus_—to give everybody a ride. - -[Illustration: FIG. 22.—_Le Petit Journal_, ZODIAC TYPE.] - -PLATE V. - -[Illustration: _ZODIAC III._] - -[Illustration: _ZODIAC IV._] - -The _Zodiac I_ was quickly followed by vessels _II_ and _III_, cubing -respectively 1,200 and 1,400 meters. The _No. II_ had a speed of -twenty, or more, miles per hour, and carried two passengers when -inflated with coal gas, three with hydrogen. The _No. III_, of torpedo -form, measured 133 feet long, 28 feet in major diameter, carried four -persons, and sailed 25 miles an hour with her 40-horse-power Ballot -engine. On August 29th, piloted by Count de la Vaulx, she competed with -the _Colonel Renard_, at Rheims, for the _Prix des Aëronats_, making -five rounds of the ten kilometer course in one hour and twenty-five -minutes, this being at the average speed of 22 miles an hour. On -October 30th, again piloted by the same renowned aëronaut, she sailed -from Brussels to Anvers, rounded the lofty Cathedral spire, and -returned to her aërodrome, traversing a distance of sixty kilometers in -one hour and twelve minutes, or with an average speed of 31 miles an -hour, a good showing for so small an air ship. - -A very handsome dirigible, named the _Belgique_, was constructed early -in 1909, by the skillful aëronautical engineer, Louis Godard, of Paris, -in collaboration with the prominent Belgian engineer and sportsman, -Robert Goldschmidt. It was a flexible balloon of elegant torpedo form, -measuring 175 feet long, 30 feet in major diameter, and 106,000 cubic -feet in volume. It was propelled by two 60-horse-power Vivinus engines -actuating two screws, made of fabric stretched over radial sticks, -and placed at either end of the spindle-shaped car. The control was -provided for by ample keel surface, an elevating plane in front, -and ingeniously designed fins on the rear of the hull to steady the -motion. The entire structure showed much originality and skill. When -the dirigible was tested near Brussels, on June 28th, it was piloted -by Louis Godard, the famous expert in sphericals, accompanied by -Goldschmidt. Godard’s début in this capacity was reported as excellent. - -The Italian government brought forth, in the summer of 1909, a swift -and elegant auto balloon showing considerable originality of design. -It has a porpoise-shaped hull of 2,500 cubic meters capacity, divided -into seven compartments, so as to obviate the accident which wrecked -the _République_. An ample keel along the rear bottom, and large -aëroplane surfaces at the stern, serve to guide and steady the vessel. -Propelled by twin screws well above a short car, she readily attained -thirty miles an hour, carrying four persons. On October 31st, starting -on her seventeenth voyage, she cruised from the aëronautic park, Vigna -de Vale, near Rome, to Naples and back to Rome by ten o’clock at -night, having sailed over the edge of the Mediterranean Sea and over -the French squadron in the bay, remaining fourteen hours in the air -and traversing 520 kilometers, or 323 miles. It was one of the finest -voyages of the year. Further details of this Italian military dirigible -_No. I bis_, together with illustrations, are given in _Aërophile_ for -January 15, 1910, together with its prototype the dirigible _No. I_, -which maneuvered so successfully in 1908. - -England and America all along had pursued an oriental, or -semicivilized, policy toward the auto balloon, languidly watching -the progress elsewhere, and hoping some time to enjoy the fruition, -if not the glory, of the costly and successful experiments made in -other countries. In 1909, however, the British government appropriated -nearly $400,000 for aëronautics, and the United States House of -Representatives voted $500,000, but promptly reversed its action, -and gave nothing, though it may be said that even then there was a -growing sentiment in favor of a more liberal policy. The movement to -secure the beginning of an aërial fleet in England is summarized in the -following paragraph.[16] - -PLATE VI. - -[Illustration: _LA BELGIQUE._] - -[Illustration: ITALIAN MILITARY DIRIGIBLE _NO. I BIS_.] - - “The naval authorities were entrusted with the building of a - rigid ship, whilst to the military department was delegated the - work of building non-rigid and semi-rigid ships. A national - air-ship fund was organized by the _Morning Post_ with the - object of purchasing a French Lebaudy semi-rigid dirigible - which would be presented to the War Office; whilst Mr. Arthur - du Cros and other members of the Parliamentary Aërial Committee - arranged for a _Clément_ non-rigid air ship of new design, to - sail from Paris to London, and also to qualify for purchase as - a unit of the British aërial fleet.” - -The non-rigid auto balloon ordered from Clément, and afterwards known -as the _Clément-Bayard II_, was the masterpiece of that skilful -designer, and occupied his best thought and energy for eighteen -months, aided by his devoted and capable engineer, Sabathier. She -was completed in the Clément-Bayard factory at Lamotte-Breuil in -April, 1910, and during the next five months made thirty-two test -ascensions and practice voyages. In particular she took a conspicuous -part in the military maneuvers at Picardie during the early half of -September, where with wonderful precision and airworthiness she made -forced voyages in fair weather and foul, remaining, when so desired, -in continuous communication with the land office by means of wireless -telegraphy. Finally, on a fair day, September 16th, the tried and -perfected vessel was brought forth from her hangar for the long -contemplated voyage to London, her machinery and rigging in trimmest -order, and her car furnished with supplies for twenty hours, or thrice -the anticipated time of transit. - -The voyage was a glorious achievement for aëronautics, and for the -enthusiastic constructor and his devoted aids. Starting at seven -o’clock in the morning, with seven men aboard, including happy Clément, -Sabathier, and an English delegate, the whalelike cruiser sailed -directly to London with admirable regularity, covering the entire -distance of 242 miles in six hours, or at the rate of forty miles -an hour, which is better time than could be made by land and water. -Enthusiastic cheers from the English spectators greeted the arrival of -this French dirigible, built for the English government. Then quietly -the English soldiers took the vessel in hand, as if performing a -familiar duty, and housed her in the _Daily Mail_ hangar, at Wormwood -Scrubs. Thus simply and without unusual incident terminated the first -motor-balloon cruise between the two countries, and one of the finest -voyages in the history of aëronautics. - -In outward appearance the _Clément-Bayard II_ closely resembled her -predecessor, except for the absence of empennage on her envelope. In -the whalelike elegance of her hull she was, in fact, a reversion to the -trim and efficient model of Renard’s dirigible of 1884, which in turn -was a fair copy of Jullien’s model of 1850, all having excellent forms -for speed and stability. But the new vessel was of greater size and -power than her predecessor. Her net buoyancy was sufficient to carry -twenty passengers. Her average speed tested in a round-trip voyage was -about 50 kilometers or 31 miles per hour when her two motors developed -200 horse power, and 55 kilometers or 34 miles per hour when the -engines developed their maximum effort of 260 horse power. The details -of construction were so elaborate and important, and so representative -of the best aëronautical workmanship of the time that a full account of -their chief features is presented in Appendix III. In passing it may be -added that some time before sailing to England the _Clément-Bayard II_, -because of her excellent workmanship and maneuvers, received the first -prize at the review of dirigibles by the French Minister of War. - -PLATE VII. - -[Illustration: _CLÉMENT-BAYARD I._ - -(Courtesy E. L. Jones.)] - -[Illustration: _CLÉMENT-BAYARD II._ - -_Photo E. Levick, N. Y._] - -[Illustration: FIG. 23.—_Clément-Bayard II_, 1910.] - -The dirigible to be purchased with the money secured by the popular -subscription organized by the _Morning Post_ was ordered from the -Lebaudy factory at Moisson in July, 1909, to be delivered directly -through the air to Farnborough before November 6, 1910. This -stipulation was severe enough, but furthermore the vessel was to -be a considerable departure from any thus far built at that famous -factory, and was to be the largest air ship yet constructed in France. -As usual the general design of the huge balloon was entrusted to the -distinguished aëronautical engineer, Henri Julliot, and this was a -certain guarantee of its successful operation. - -The general features of this great military dirigible resemble those -of her prototype, the _Patrie_, differing chiefly in the shape of her -hull and the method of stiffening. The hull itself was more longish -than the _Patrie’s_, but had the same sharp prow and blunt stern; for -a blunt stern offers better support to the empennage planes, though -it increases the resistance more than a tapering stern. The trussed -framing to stiffen the ship was no longer a platform inserted in the -base of the hull, but a long trussed beam of cruciform cross section, -made of steel tubing and suspended intermediately between the hull and -car. - -The hull was of excellent workmanship and bold design. The envelope -was of rubberized tissue, measured 338 feet in length, 39.4 feet in -diameter and cubed 353,000 feet. Its length was, therefore, 8.5 times -its diameter, an extraordinary proportion for a balloon of the flexible -type. The hull was provided with three ballonets, two ripping panels, -and various valves, as shown in the scale drawing. - -[Illustration: FIG. 24.—MORNING POST DIRIGIBLE, 1910.] - -The car, made of steel tubing and large enough for twenty persons, -carried two Panhard-Levassor motors of 135 horse power each, actuating -two Chauvière wooden screws, sixteen feet in diameter, placed on either -side, well outward and upward, the transmission gear permitting either -engine, or both, to drive the screws at one time. Below the car and -well forward was a ground keel, or post, on which the whole vessel -could pivot with the wind, when riding at anchor, while a shorter -ground post was placed at the rear of the car. - -The controlling surfaces were adequate and skillfully arranged. To -maintain steadiness and directness of flight, fixed empennage planes, -both horizontal and vertical, were provided, some attached to the stern -of the hull, others at the rear of the trussed suspension beam. To -direct the up and down movement, ailerons placed well to the front and -rear of the long framing, were turned about conjunctively in opposite -directions, thus causing the vessel to raise or lower her bow. Needless -to say, all these navigation appliances worked with ample force and -effectiveness from the beginning of the earliest tests. - -After four preliminary ascensions the great air ship started from -Moisson to her destination at Farnborough, having on board Henri -Julliot, Louis Capazza, the pilot, Alexander Bannerman, director of -the aëronautic military school at Aldershot, and five other men. It -was a triumphant and glorious voyage, one of the most splendid in -the history of aërostation. Piloted by aid of chart and compass, and -by signal fires and captive balloons arranged along her route, the -vessel followed a direct course, without check or hindrance, crossing -a wide part of the English Channel and arriving before the hangar at -Aldershot, where the British soldiers awaited her, and where she was -safely landed, having made the whole voyage of 230 miles in 5.5 hours, -at a level varying between five hundred and two thousand feet. As -shown by the accompanying map, about one third of the route lay over -the Channel, or, more accurately, 78 miles, which was traversed in two -hours. Thus the whole journey was accomplished at an average speed -of nearly forty-two miles an hour, or in less time than it could be -effected in any other way than through the air. - -[Illustration: 15 Novembre 1910 - -FIG. 25.—ROUTE OF BRITISH MILITARY DIRIGIBLES FROM FRANCE TO ENGLAND, -1910.] - -The United States War Department, in 1908, started an aërial squadron -by purchasing from Thomas S. Baldwin, for $10,000, a tiny air ship of -the flexible type, a trifle larger than Santos-Dumont’s _Runabout_, but -in fact the smallest military dirigible then in existence. It had a -rubberized gray silk cylindrical hull slightly tapering toward the rear -and terminating in ogival ends, its length being 96 feet, its major -diameter 19½ feet. From this was suspended, by means of netting and -steel cables, a longish car having at the rear a double rudder working -about a vertical hinge, at the front an elevating plane and an 11-foot -wooden screw driven by a Curtiss 20-horse-power water-cooled engine. -With two men aboard, this vessel readily attained over twenty miles an -hour in a straightaway course, and at times more nearly thirty miles an -hour. Its total ascensional force was 1,350 pounds, of which 500 were -available for men, ballast and supplies. - -Santos-Dumont’s most strenuous disciples outside of France were found -among the German military officers. These advocated and promoted both -the semirigid and the flexible types of auto balloon, with such ability -as to match the best productions of the foremost French designers. -The most successful pioneers of these two types in Germany were -respectively, Major von Gross, commander of the balloon battalion at -Tegel, near Berlin, and Major Von Parseval of the Bavarian army, and -director of the Society for the Study of Motor Air Ships. - -Beginning in 1907, a number of Gross auto balloons were built in -succession, for the German Aëronautical Battalion, by Master Engineer -Basenach, under the supervision of its commander, Major Gross. The -first was intended only as a model, though it was large enough for -two passengers. It cubed 63,000 feet, but having an engine of hardly -more than 20 horse power, was necessarily slow. It was succeeded by -the _Gross I_, and others, all having rigid ventral parts, like the -_Patrie_, but with hulls of rather better form for speed and bulk -combined, having blunter bow and longer stern. - -PLATE VIII. - -[Illustration: _U. S. SIGNAL CORPS DIRIGIBLE I._ - -(Courtesy U. S. Signal Corps.)] - -[Illustration: _GROSS II._ - -(Courtesy E. L. Jones.)] - -The second Gross air ship, built in 1908, cubed 176,000 feet, and -attained a speed of 27 miles per hour, driven by two 75-horse-power -Daimler motors. On September 11th of that year, with four persons -aboard, she made a round trip from Berlin lasting 13 hours, covering -176 miles, and attaining altitudes up to 4,000 feet. This was one of -the finest voyages known at the time. This air ship was purchased by -the German government, named _Gross I_, and sent to Metz. A detailed -description is given in Appendix III. - -The _Gross II_, brought forth in April, 1909, resembled her predecessor -in build, but had greater power and speed. Her hull cubed 176,000 -cubic feet, had a blunt bow, full body and sharp stern, was provided -with horizontal and vertical keels, a sliding weight, and a ballonet -at either end. She was propelled by two Körting engines of 75 horse -power each, actuating two three-blade propellers. Under the action of -her keels and stabilizing planes and rudder, her motion was steady and -precise. A special feature of this air ship was the wireless telegraph -equipment by which she could send messages in all directions over a -range of 300 miles or more. She made many practice voyages during the -season of 1909, sometimes alone, again in concert with other auto -balloons and with troops. In August she made a fine voyage of sixteen -hours, from Tegel to Apolda and return, traversing 470 kilometers. - -The above described vessel was followed by others, large and small. -The _Gross III_ measured 70 meters long, cubed 7,500 meters, and was -propelled by four Körting motors aggregating 300 horse power. This was -a splendid vessel, and one of extraordinary speed. - -Various auto balloons of the Parseval type were designed by Major Von -Parseval of the Bavarian army, who also was one of the inventors of the -kite balloon. Satisfactory experiments with his air ship were made as -early as 1906. These formed the basis of larger vessels, subsequently -constructed in the same factory of August Riedinger of Augsburg, -for the Motor Air Ship Study Society, of which Parseval was general -manager. This society, organized practically at the command of the -Emperor, purchased the Parseval patents and began the development of -auto balloons as a business enterprise, soon furnishing a series of its -flexible air ships to the German army. - -After the experiments of 1906, the Parseval air ship was enlarged from -2,500 to 2,800 cubic meters, its length becoming 52 meters and its -major diameter 8.7 meters. Its hull was of cylindric form, with rounded -bow and egg-shaped stern; had two air bags—one fore, the other aft—and -at the stern carried two fixed horizontal planes and a vertical rudder. -From this envelope the car, made largely of aluminum, was hung by steel -cables, and on its bottom had trolley wheels resting on suspension -cables joining the front and rear parts of the hull. The vessel was -propelled by a 50-horse-power Mercedes motor actuating a four-blade -screw propeller 13 feet in diameter, mounted between the car and hull. -This screw was made of thin steel tubes covered with shirting. Among -the merits of Parseval’s air ship may be mentioned its lightness and -demountability, and its kite-like effect on the air, got by canting -the hull while the car, rolling on the suspension cables, allowed -the screw mounted above it to thrust horizontally. The canting was -effected by giving one ballonet more air than the other, thus causing -its end of the hull to sink. The speed was about twenty-five miles per -hour. - -PLATE IX. - -[Illustration: _PARSEVAL I._ - -(Courtesy W. J. Hammer.)] - -[Illustration: _PARSEVAL II._ - -(Courtesy E. L. Jones.)] - -The second _Parseval_ was of greater bulk and power than her -predecessor. Her hull which was of cylindric form, with round prow -and pointed stern, measured 190 feet long, 30.5 feet in diameter, and -113,000 cubic feet in volume. She resembled her predecessor in the -arrangement of the two ballonets, and in the “loose,” or trolley, -system of suspension of the car. The propeller was a unique patented -device of Von Parseval’s. It had four cloth blades so weighted with -lead as to stand out firmly under centrifugal force, assuming an -effective shape for propulsion, though limp and deformed when at rest. -Various interesting evolutions were performed by this vessel in the -autumn of 1908, including tests imposed by the military authorities, -as a condition of purchase by the government, one requirement being a -voyage of one hour at an altitude of 1,500 meters; another requirement -being a continuous cruise of twelve hours. These tests completed, -the Motor-Luftschiff-Studien-Gesellschaft sold its proud ship to the -Vaterland for 210,000 marks. - -About the same time the War Department purchased the _Gross I_, already -described, and Zeppelin’s third great ship, naming it _Zeppelin I_. -Germany thus began her program of developing a great aërial fleet, -by acquiring three powerful and well tried ships, each capable of -remaining all day in the air, and having a radius of action of several -hundred miles. They were frequently called upon to make test voyages in -all kinds of weather, to maneuver with the troops, to pass in review -before the Emperor, at times conveying prominent officers and members -of the noblest families, including Prince Henry and the Crown Prince, -who manifested a fondness for navigating about their newly opened -empire of the sky. But sometimes the tests were crucial. On September -11, 1908, both the _Gross_ and _Parseval_ were summoned to Potsdam by -His Majesty. They set forth from their sheds, at Tegel, in face of a -strong wind. After journeying some distance they each had to abandon -the voyage, the _Gross_ returning home, and the _Parseval_ falling to -the ground owing to an accident. - -The third Parseval air ship was brought forth on February 18, 1909, by -the Luftfahrzeug-Gesellschaft, an aëronautical firm founded by merging -the Motor-Luftschiff-Studien-Gesellschaft with the A. E. G. This vessel -closely resembled her predecessor, but possessed greater size, power, -and perfection of detail. Her hull at first measured 224 feet long, -47 feet in diameter, and 198,000 cubic feet in volume, but later was -enlarged to 235,000 cubic feet by increasing its diameter. - -Her car, which could accommodate twelve passengers, was framed of steel -tubing covered with canvas, and was divided into two parts, separated -by the big gasoline cylinder running athwart ship, the passenger cabin -being to the fore, the engine room aft. Here were stationed the two -engines, of 120 horse power each, actuating reversible right and left -_Parseval_ screws 13 feet in diameter, located to the rear, well aloft -and outward on either side. In the forepart of the passenger cabin was -space for the pilot and his navigating appliances; his chart desk, his -valve controls, his statoscope, manometers, etc. - -The great ship with her nine tons burden was to have sailed from -Bitterfeld to Frankfort, for the Aëronautical Exposition, but owing -to excessive gales, she was sent by rail. Once there, she made many -excursions, at times carrying passengers at a schedule rate, reported -to be 200 marks for a voyage of one to two hours. In October she made -an inter-city excursion covering a distance of nearly 500 miles, during -which she passed four nights in the open air, finally returning in -good form to Frankfort. On October 27th she made a farewell tour about -Frankfort, then voyaged along the Main and down the Rhine valley to -Cologne, there to participate in the aëronautic military maneuvers, -together with the _Parseval I_, the _Gross II_ and the _Zeppelin -II_. Having passed creditably through these and other operations in -the autumn, she was eventually stationed at Tegel, as a part of the -national fleet. - -The fourth _Parseval_, a smaller vessel, was built for the Deutscher -Aëro Club early in 1909. Her hull cubed 113,000 feet, and her framing -was made of the strongest materials, carefully hollowed, to eliminate -undue weight. At the rear of the car, on either side, were two -100-horse engines, driving two _Parseval_ propellers at a common speed, -whether both engines were in operation, or only one. In many respects -she resembled her immediate predecessors, and her little successor -_Parseval V_ of 1,200 cubic meters capacity and 30 meters length, built -for the Imperial Automobile Club. - -The maneuvers at Cologne constituted the first grand demonstration of -the new fleet of military dirigibles, and proved a severe test of the -powers of the air ships, even when manned by experienced crews and -commanded by regular military officers. Two companies of the balloon -corps battalion were in attendance. Large provisions of hydrogen loaded -on wagons, each carrying 100,000 cubic feet, were kept in readiness to -be attached to an express train and rushed at the first alarm to any -balloon in need of replenishing. On Sunday, October 31, three of the -dirigibles representing each type, _Zeppelin IV_, _Parseval I_, _Gross -II_, left Cologne together, by official order, and returned after -flights of 7, 10 and 11 hours respectively, covering in the aggregate -930 miles. Again, leaving Cologne shortly before noon on November 3d, -they went down the Rhine, simulated a concerted attack on the great -fortress of Eherenbreitstein, and returned in the evening, each having -covered 155 miles. And so on for many days they continued to execute -maneuvers under military orders and in severe forced marches. - - - - - CHAPTER VI - - DEVELOPMENT OF RIGID DIRIGIBLES - - -Count Ferdinand von Zeppelin, the famous cavalry general of Würtemburg, -and hero of the Franco-Prussian war, after retiring from the army, -organized, in 1898, a limited liability company for the purpose of -developing a new type of dirigible which he had long contemplated. -It was to be a vessel far larger and swifter than any the world had -yet seen. In the summer of 1900, after two years of industrious -experimental research and active construction, he brought forth from -his floating laboratory on Lake Constance, near Manzell, the first -of those wonderful air ships which have aroused such expectation and -enthusiasm in Germany. In outward appearance and in its chief features -of design it typified the whole series of motor balloons thus far -developed and navigated by that illustrious inventor. Many valuable -improvements were added, as a result of trial and the advance of the -collateral sciences; but the fundamental plans seem to have proved as -practical as they were bold and original. One by one were surmounted -the greatest obstacles, physical, financial and finally political; for -the Prussian Ministry did not favor his project at first, and many -aëronautical adepts were adverse to it. Those huge ships faced the fury -of many a tempest; their dauntless builder endured the storm of hostile -criticism; but in the end, builder and ships alike won the plaudits of -a proud empire and of an astonished world. - -Outwardly a Zeppelin balloon may be described as a long cylinder with -ogival ends and a V-shaped keel running the length of its bottom. From -afar the cylinder and pointed ends appear circular in cross section, -but they are sixteen-sided. About one-third the distance from either -end of the great ship a small boat is suspended from the hull so -closely that at those places the keel is omitted to make room. These -two boats are rigidly connected with the hull and support it when the -vessel rests on, or is towed along the water. Within them are the crew -and petroleum engines, while above them and outward on each side of -the hull, and fastened to it by outriggers, are two pairs of screw -propellers, so placed as to exert their united thrust along the line -of resistance. In some cases the crew can walk through the V-shaped -keel from one boat to another, the passageway being illuminated here -and there, by transparent covering, or windows of celluloid, along the -sides and floor. Again an observer may climb up through the hull and -take observations of the sky from above. Telephones, electric bells, -and speaking tubes serve to transmit intelligence from one part of the -vessel to another. - -The frame of the hull is formed of sixteen longitudinal beams, or -girders, of trellised metal work running from prow to stern and -riveted at regular intervals to cross bridges of similar trellised -metal work, each cross bridge being a sixteen-sided wheel with -trellised rims strengthened by radial rods running inward to a -central flange of sheet aluminum. Thus the body of the vessel is -divided into many compartments, each bounded by two wheels, and the -surrounding longitudinal beams. Each compartment contains a hydrogen -balloon, or sac, which fairly fills it and exerts a lift against -the longitudinal beams and against a netting formed of ramie cords -stretched from wheel to wheel, diagonally between beams at their -inner corners. Similarly the outward corners of the beams are joined -by strong diagonal wires for the purpose of rigidity, and the whole -external frame is covered with a heavy fabric which forms the outer -skin, or wall of the hull. Between this skin and the hydrogen bags -are air spaces, as also between bag and bag. Thus the whole vessel is -buoyed up by numerous thin hydrogen sacs, protected by the frame and -outer skin from the direct sun, from foul weather, and from external -shocks. The gas bags are also separated from each other by the bridge -work and flanges of aluminum. - -PLATE X. - -[Illustration: _GROSS III._] - -[Illustration: ZEPPELIN AIRSHIP STRUCTURE.] - -Obviously there is a material advantage in having many gas cells and -two propelling plants; for if one fails it may not prevent navigation. -The tandem arrangement of bags separated by the wheel-like cross -bridges also allows the balloon to rear any amount without material -displacement of the gas, or dangerous increase of pressure; for it must -be remembered that a single hydrogen sac extending the full length of -an up-ended balloon of such length, would have an outward pressure of -about thirty pounds per square foot greater at the top than at the -bottom. The poise of the vessel is maintained by shifting weights, and -also by use of fins, or rudders, when driving through the air; but -those arrangements vary in the different machines. So much for the -general features of these wonderful ships, of which four were built -during the decade from 1898 to 1908, and several more since that period. - -The construction and trial of Count Zeppelin’s first air ship proved a -formidable task, requiring all his resources of money and mechanical -skill. As it rivaled in size and fluid displacement a large ocean -liner, it could not well be launched and landed, except on the water. -It was therefore housed in a wooden shed 472 feet long, floating on 95 -pontoons, and so anchored as to swing freely with the wind and assume -its direction. This shed, as well as the ship, was very costly, and -in an unfortunate hour was torn from its moorings by a tempest, which -did other damage entailing great expense and time for repairs. The -inventor’s resources were becoming strained; for, as reported, the shed -cost $50,000, while the first balloon cost more than twice that sum. - -Finally, the first launching was officially set for June 30, 1900. The -lake was thronged with people massed along the shores, and dotting -its surface with every kind of craft, from the fisherman’s primitive -boat to the handsomest private yacht, or launch. All day the expectant -multitude waited, only to learn at dusk, that the inflation was not -completed. Next day they tarried again till evening, and merely saw -the raft on which the balloon rested, towed out of the floating house. -On the third day, July 2d, those who waited were rewarded with an -interesting spectacle. The long stiff air ship was drawn forth from -its shed, like a ram rod from a gun. Count Zeppelin, with two men, -occupied the front boat, while two others took the rear one. After -careful adjustment the vessel was liberated, at eight o’clock, rose -slowly and advanced over the water, accompanied by the droning of its -propellers and the shouts of the delighted spectators, who realized -that they might be witnessing the commencement of a new epoch in -aërial navigation. But the voyage was not an unqualified success. -The controlling mechanism became deranged, the framework was bent, -and the propellers could not be worked properly. A gentle wind was -blowing and the vessel drifted with it, having an independent speed -of only thirteen feet per second, at best. At eight-twenty she reached -Immenstadt and landed on the water, having voyaged three and one half -miles, and having attained a height of thirteen hundred feet on a part -of the journey. - -At that date the _Zeppelin I_ was by far the largest and most -elaborate air ship ever constructed. Her hull measured 416 feet long, -38 feet across, cubed nearly 400,000 feet, weighed 9 tons, and had a -displacement of 10 tons. The trellised frame was made of aluminum, and -its body comprised seventeen compartments, of which fifteen were 26 -feet long, and the other two 13 feet long. The outer cover was of linen -treated with pegamoid and tightly stretched. The hydrogen sacs were of -thin fabric. The propulsion was effected by two benzine motors, one in -either boat, which together developed 32 horse power, each driving, -by means of bevel gears and shafting, a pair of four-blade propellers -3.77 feet in diameter, at 1,100 revolutions per minute. Steering -sidewise was effected by means of vertical rudders, while the trim was -controlled by horizontal rudders at either side of the vessel, as also -by means of a sliding weight which could be drawn fore and aft by means -of a winch. Naturally some of these details were superseded ere long by -better devices suggested by subsequent experience. - -On October 17, 1900, _Zeppelin I_ made her second voyage, and with much -better result. Starting from the same balloon house at Manzell, at -four-forty-five, she promptly rose a thousand feet, and maneuvered in -a seven-mile wind, steering in great curves at the will of the pilot. -At times the speed was nearly twenty miles an hour, as determined by -continuous observations of the balloon’s position, taken from three -points of a triangle, together with the velocity of the wind on its -course, duly recorded by an anemometer. Finally a landing on the water -was made at six o’clock, without mishap. - -This last demonstration left the Count triumphant in other respects, -but without sufficient funds to bring his invention into practical -use. He must, therefore, look for additional money for the proper -continuation of his great work. The financial task thus ensuing -occupied much of his time during the next five years, but he finally -secured capital enough to continue his experiments and to build a -second airship. This was completed and ready for trial in the latter -part of 1905. - -_Zeppelin II_ resembled its predecessor in appearance, but embodied -many improvements suggested by the former trials. Its hull was 414 -feet long, 38 feet in diameter, held 367,000 cubic feet of hydrogen -in its sixteen gas bags, and weighed with all appliances and cargo, -about nine tons. It was, therefore, about ten per cent smaller than -its predecessor; but at the same time it was far better powered than -the earlier one, and more effectively controlled. Each boat carried -an 85-horse-power Daimler benzine motor, actuating two enlarged -propellers. Ample steering surfaces, operated by the helmsman in the -front boat, served to turn the great ship about either of three axes -and, at the same time, to displace her bodily up and down in the air, -either by direct lift or by canting her hull so that her screw thrust -and the pressure on her sides would produce the desired translation. - -Two trials of Zeppelin’s second air ship were made on the Borden-See, -one on November 30, 1906, the other on January 17, 1907; but both -met with serious accident. In the first trial the balloon was towed -by a motor boat some distance, then cut loose in the wind, which -was carrying it forward faster than the boat. But it soon became -unmanageable and plunged into the water, suffering considerable damage. -In the second trial it flew for a short time at a speed of thirty -feet per second, when the engines were developing 36 horse power. -Some maneuvering was effected in a strong wind, but presently the -propellers stopped, the vessel dropped to the shore and was anchored on -the ground. During the night it was so badly damaged by the wind that -Count Zeppelin ordered it to be taken to pieces to furnish material for -further construction. - -The loss of two mammoth air ships after such brief trial seemed -enough to appall even a sturdy general of the Prussian army; but -Count Zeppelin was too resolute to waste time in futile tears and -hopeless dejection. Strong natures are usually stimulated by disaster, -and aroused to fuller energy, to grimmer determination, if not to -desperate hazard. However, not desperation, but buoyant hope and high -expectation, based on ample experience, were now his ruling motive. Had -not his ship attained thirty feet per second with less than one fourth -her motive power? The year began with disaster indeed, but he intended -it to terminate in glorious victory. And such, indeed, was the happy -issue. - -October, 1907, witnessed the launching of _Zeppelin III_. She had the -same length as her immediate predecessor, but she was a luckier vessel -and better powered. On her official trial she voyaged at the height of -half a mile, carrying eleven persons sixty-seven miles in two hours -and seventeen minutes, or at more than twenty-nine miles per hour. -This was a record velocity exceeding that of the best military balloon -in France. At times she attained a velocity of fifty feet per second, -thus considerably outspeeding the swiftest ocean liner. Moreover, her -stability and steering qualities were excellent. With pardonable -elation, therefore, the illustrious inventor could report to the -Minister of War the complete success of his experiments. And with good -reason the German government now granted financial aid to test more -fully the merits of the rigid system of construction. - -With this assistance the industrious aëronaut erected a new floating -house on the Borden-See at Friedrichshafen, and began the construction -of a still larger air ship embodying further improvements in various -details. _Zeppelin IV_ was 446 feet long, 42.5 in diameter, held -460,000 cubic feet of hydrogen in her sixteen compartments, and had a -total buoyancy of sixteen tons. She had a surplus buoyancy of over two -tons, carried a crew of 18 men, and had an estimated range of action -of eighteen hundred miles. When drawn from her shed in the autumn of -1907, her great buoyant hull resting lightly on the water supported by -her two floating cars, she had all the appearance of a royal passenger -express ready for important service. In general features the vessel -was like her three predecessors, but in the center of the keel, with -transparent floors and windowed sides, was a special stateroom designed -for passengers only. This seemed very suggestive, if not prophetic, -of the future trend of aërial navigation. Moreover, the mechanism of -propulsion and control were increased in power and effectiveness. -In each boat-like car was a 110-horse-power Daimler benzine engine, -actuating a pair of three-blade propellers about 15 feet in diameter. -A large vertical rudder, mounted on the extreme end of the stern, and -supplemented by a pair of smaller vertical rudders at either side of -the stern, served to steer the vessel right and left. For steering -up and down, as also for exerting a direct lift up or down, four -superposed planes like a Venetian blind were placed at either side of -the hull fore and aft, at about the same level as the propellers. In -addition the hull was provided, like a feathered arrow, with fixed -fin-like planes at the stern, both vertical and horizontal, for -securing steadiness of flight. - -Several trials of this leviathan were made preliminary to her official -government test which, if satisfactory, assured her purchase by the -German government for $500,000. At the builder’s suggestion this test -should include a voyage of 24 hours duration, a safe descent on land or -water, an ascent to 4,000 feet, and the fulfillment of various secret -requirements. In the autumn of 1907 a successful voyage of eight hours -was easily accomplished. In the early part of the next summer, 1908, a -series of voyages were made which aroused intense interest throughout -the civilized world. On June 13th the great ship, starting from her -harbor at Friedrichshafen, sailed over the Alps to Lucerne, steering -in among the mountains; here buffeted by eddies, and cross currents, -there stemming such stiff head winds that her shadow could hardly -creep forward over the ground, again driving through a dark lowering -hailstorm which pelted with ominous thunder on her resounding hull; but -at length reaching Lucerne safely, then returning in triumph to her -harbor at Friedrichshafen. For twelve hours the stanch vessel endured -the elements, by no means hospitable, and in that period voyaged 270 -miles at an average speed of 22 miles an hour. It was a record journey -and a triumph in the art. - -The following picturesque account of a flight in Count von Zeppelin’s -gigantic air ship, written by Emil Sandt, appeared in the _Scientific -American Supplement_ of August 15, 1908: - - “Early in the morning Professor Hergesell, Freiherr von - Bassus, Dr. Stalberg, Herr Uhland, and myself set out in - Count Zeppelin’s launch for the shed in which the great air - ship is housed. When we arrived everything was in readiness - for us. Count Zeppelin is proud of the fact that his colossal - craft can be drawn in and out of the shed with very little - help. In seven minutes the huge gas bag had emerged, and a - few minutes later we were floating up to the sky. I took my - station in the central car or cabin, a comfortable room flooded - with the yellow light that filters through the translucent - balloon fabric of which the walls, the floor and the ceiling - are constituted. Comfortable seats suspended from fine chains - provide a seating capacity for a dozen passengers. - - “For a great portion of their length the walls are provided - with celluloid panes. The floor is also transparent wherever - it is not used as a footway. Seated comfortably in the central - car, I could look down through my knees and see the green - earth, water, people, cities and castles far below. I could - also see birds circling around and fluttering anxiously, - evidently frightened by the strange giant of the air. - - “We crossed over to the Ueberlinger See, traversed the - intermediate neck of land, and turned into the valley of the - Rhine at Konstanz. Here I left the central car and walked - toward the rear car along the keelway, which is flanked with - balloon cloth, and which is closed at the end of the keelway - by a celluloid door. I opened the door and stepped out on the - narrow aluminum gangway, which runs down sharply to the rear - car. The gangway has no protecting handrail. It is merely - ribbed to give a better foothold. That apparently flimsy - structure bridges a chasm of twenty feet between the end of the - keelway and the car. From below, the passage from the keelway - and the car must seem perilous indeed, but up in the air ship - itself no fear is felt. I stood on this narrow bridge and gazed - on the landscape. To the north I could see the Hohendtwiel. - Behind us lay the Swabian See glistening in the morning’s sun. - In the southeast I saw Thurgau wrapped in violet light. On the - horizon the lofty peak of the Saentis rose broad and jagged, - capped with ice and snow. Below us writhed the Rhine. I looked - across at the propellers. Count von Zeppelin had signaled full - speed ahead. The giant air ship trembled. The propellers seemed - like disks, revolving with furious speed and yet as transparent - as a locust’s wings. They gave out a note like that of a deep - organ, so loud that the human voice, even when lifted to a - shriek, could hardly be heard. - - “I walked down to the rear car to obtain a better view. Here - the gigantic craft could be seen in a wonderful perspective. - The sensation was strange. The giant ship obediently sank and - rose. Obediently moved to the right or to the left, slavishly - following the slightest pressure of the human hand. Sometimes - its angle was such that the entire fabric seemed inclined like - a kite. At times the forward car lay below us; at times we had - to look up at it. - - “As we neared the splendid falls of the Rhine at Schaffhausen, - the Count brought the air ship down, in order to ascertain - whether the eddies occasioned by the waterfall would have any - effect. - - “We turned into the Reusstal, but were buffeted by the wind - all the way up the valley. To the south the sharp jutting - peak of Mount Pilatus hove in sight. Soon Lucerne appeared, a - jewel among cities. The lake itself shimmered brightly where - it was struck by the sun; its darker portions lay like an - emerald, held in a setting of heliotrope. It was like a melody - in colors. Below us in Lucerne itself there was a hubbub and - a great jubilation. The streets were crowded with gayly clad - people. The roads were a-swarm. Zeppelin guided his air ship - down, and allowed it to glide full speed over the city at the - height of a church steeple. - - “We traveled over the Vierwaldstaetter See, and crossed to - Knessnacht, to Zug Lake, and up northward to Zug itself. Then - came the most difficult task which Professor Hergesell had - assigned to the air ship. The craft was to carry us straight - across to Lake Zurich, through a narrow pass where it would be - caught in a veritable cyclone. The motors groaned and rattled. - The propellers howled a deep groaning song. The air ship did - all that it could. The wind was dead against us, traveling - with a velocity of nearly thirty-one miles an hour. The Count - could easily have arisen and escaped the fury of the blast, - but it was his purpose not to avoid obstacles, but to court - them. Whenever the great air ship showed signs of swerving, it - was brought back to its course. Far below us in the valley the - sharply marked shadow of the air ship, crawling slowly from - tree to tree, showed us how hard it was struggling. There were - minutes when it seemed as if we stood stock still, despite the - infernal music of the propellers. Gradually the nose of the - craft was thrust forward; once more the air ship mastered the - winds. We had forced our way through the pass, and were dashing - on at full speed. The vast shadow below us traveled with the - velocity of a bird over the mountain, valleys, cliffs and rocky - points, over railway embankments and road, over water and land.” - -Two attempts were made in July, 1908, to complete the government test; -but they proved abortive, and in the second one the hull was damaged by -the wind pushing it sidewise against the shed, as it was being towed -out by motor boat. This accident caused a delay of two weeks, much -to the disappointment of the expectant populace. As a consequence -Zeppelin resolved to begin the next attempt unheralded. He had the -repairs made quickly and all was ready early in August. - -On Tuesday, August 4th, at six forty-five in the morning, the great -twenty-four hour test for the government began, without previous -announcement, but with fairest prospect of success. Sailing from -Friedrichshafen, Zeppelin purposed to follow the Rhine as far down -as Mayence, then return in a direct line to his starting point. All -went splendidly at first. He passed Constance at seven o’clock in -the morning, Basle at nine-thirty, Strassburg about noon, then with -slower speed passed Mannheim at two-fifty and Darmstadt at four-thirty. -At about six o’clock a descent was made at Oppenheim, eleven and a -quarter hours after starting. The air ship had voyaged 270 miles at the -average speed of 22 miles an hour. A wonderful demonstration it was -for the inhabitants of that historic valley, and a glorious tour for -the brave old sailor and his crew. Resuming the voyage, Mayence, the -turning point, was reached at eleven o’clock at night, and the vessel -was headed for home. But now the engines, being overworked, could -not maintain the usual speed, which therefore was lowered to twelve -miles an hour. Next morning at eight o’clock, after Stuttgart had been -passed, a descent had to be made at the village of Echterdingen, to -adjust and overhaul the machinery. Ninety-five miles of the return had -been made in nine hours. - -It was most unfortunate that a landing had to be made without a harbor, -particularly as a gale was in pursuit of the vessel. Ere long she was -torn from her moorings by a squall, carried into the air, and set on -fire, probably by an electric discharge. Immediately the great hull was -enveloped in flame and completely destroyed, leaving a tangled network -of distorted framing. It was a dismal termination to the greatest motor -balloon voyage in the world’s history up to that date; for the vessel -had been in the air continuously for twenty and three-fourths hours and -had traveled 378 miles. - -The hardy and venerable hero of so many voyages and long continued -experiments quite broke down at the sight of his grandest vessel in -ruin. But an unlooked for and a sudden turn of events brought him the -greatest triumph in his darkest hour. While the world expressed its -grief and sympathy his loyal countrymen hastened to his relief in an -admirable burst of enthusiasm. Within twenty-four hours the government -had made him a grant of $125,000, and subscriptions offered in all -parts of Germany brought the sum to over $500,000. By October, 1908, -the total gift amounted to $1,500,000, which was paid to the Zeppelin -Air Ship Company, formed for developing and building air ships on a -large scale. A tract of 300 acres was secured at Friedrichshafen for -an air ship factory. Here was erected the necessary shops, hydrogen -plant, balloon harbor, and everything necessary to enable the company -to construct several mammoth air ships each year. To these new grounds -the Count’s former interests were gradually conveyed, while his old -station, with its air ship dock on Lake Constance, was converted into a -military post by the German government. - -After the destruction of _Zeppelin IV_, its predecessor, the Count’s -third air ship, was again prepared for service and for new triumphs. -Her hull was lengthened by the addition of a cylindrical section having -the length of one compartment, or about 26 feet. This alteration gave -a considerable increase of net buoyancy with but slight increase of -resistance. The dimensions now were: length 446 feet, diameter 38 -feet, volume 423,768 cubic feet. The gas was contained in sixteen -sacs, twelve in the cylindrical part and two at each end. The ship -was propelled by two 85-horse-power engines, supplied with sufficient -gasoline for a forty-one hour voyage at 25 miles per hour. The loss of -gas by leakage was less by weight than the loss of fuel. The famous old -cruiser, thus remodeled, was operated in the autumn of 1908 with her -usual precision and grace; thus winning new distinction and renown. On -one occasion she had as passengers the Crown Prince and the Kaiser’s -brother, Prince Henry. The Emperor himself witnessed the demonstration, -and decorated the Count, referring to him as “the greatest German of -the century.” Soon afterward the ship was taken over by the government -and assigned to the Prussian Battalion of Aëronauts, being christened -_Zeppelin I_, since it was the first vessel of the kind taken into the -military service. - -Beginning with March 9, 1909, the military _Zeppelin I_ was kept in -active operation by the officers, and subjected to a wide variety of -tests day by day. She was driven through rain and snowstorms, at all -elevations up to a mile; she was anchored over land and over water, -sometimes exposed for hours to a gale; she was steered in and out of -her shed without the aid of her floating raft; she was sent on long -trips, landed in the open country, by day and by night, and returned to -harbor in safety. On one occasion she carried twenty-six passengers for -over an hour and a half; again she made an endurance flight of thirteen -hours. These maneuvers exhibited for the first time many capabilities -of the ship, which all along had been stoutly affirmed by the inventor, -but questioned by his critics. - -On April 1, 1909, at four o’clock in the morning, the renowned -_Zeppelin I_, with the Count as helmsman, started through the rain -and wind on a voyage from Friedrichshafen to Munich, a hundred miles -distant. The ship followed the railway as far as Ulm, guided by the -station lights, which were kept burning all night to mark the route. As -she approached Munich, at the appointed hour of nine next morning, her -approach was announced from afar by the droning of her machinery and -propellers, whereupon she was welcomed by loud music from many bands -and the joyous ringing of all the bells in the city. The Prince Regent -of Bavaria and a great throng of applauding citizens awaited her at the -Teresenhohe park. Presently the swift cruiser approached, sailing over -the steeple tops like a monstrous arrow. She halted before the Regent -and dipped her bow three times, in graceful salute. Then she circled -widely over the city, intending to land at the Oberwiesenfeld Parade -Grounds, where part of the garrison troops were drawn up to receive -her. But now, while so near the goal, she found it difficult to stem -the increasing gale, and unsafe to land; so, with her bow pointed to -the city, and propellers humming furiously, she gradually yielded to -the storm, and drifted slowly backward toward the northeast. - -The crucial hour had come for this stanch vessel and her audacious -captain. They wrestled with the storm bravely and obstinately, but -were beaten back steadily, with no port in view. The Count determined -to weather the gale till it should spend its fury. He coolly sent an -aërogram to Munich, saying that all was well and that he might reach -the city late in the day. Observing a suitable place to land, near -the village of Loiching, he pointed the prow of his ship downward, -approached the earth and cast anchor. As the front car touched the -ground it was grasped by the willing hands of thronging peasants and -villagers. Presently the ship was taken in charge by a military -relief party which the Count had hailed on the way, at Guendelkoven, -and which had hastened to his aid in automobiles. Fifty soldiers, in -regular shifts, that night held the bow of the vessel by a short leash. -The anchor was firmly fastened, and additional ropes secured the bow -to an unwheeled wagon loaded with stones. Thus all night long that -mighty hull swayed to and fro in the passing storm, securely as a ship -anchored at sea. - -PLATE XI. - -[Illustration: ZEPPELIN DIRIGIBLE RESTING ON THE WATER. - -_Photo E. Levick, N. Y._] - -[Illustration: ZEPPELIN DIRIGIBLE OVER ZÜRICH. - -_Photo E. Levick, N. Y._] - -Next morning the vessel was well replenished and headed for home, by -way of Munich. The return was easy, for the wind had nearly reversed -its course. Sailing at 32 miles an hour, with a quartering current, -the stormbeaten ship soon reached Munich, where she was hailed with -boundless enthusiasm. The Prince Regent entertained the Count during -his sojourn of three hours, and decorated him with a gold medal. The -ship then sailed for Friedrichshafen, with the full speed of the wind -and of her propellers, at one time attaining 68 miles an hour. At -nightfall she landed gently on the lake near Manzell, having weathered -that tempestuous voyage without serious mishap. - -This was a splendid proof of her stanchness; but a few days later -she was put through other tests quite as severe, one being a night -voyage of thirteen and a third hours, after a day of busy maneuvering. -Following this came her still longer voyage, to Metz, where she was -stationed as a frontier war vessel, and one of a considerable fleet -contemplated by the German government. - -In the meantime the energetic Count had started his fifth vessel, or -military _Zeppelin II_, which now was nearing completion at the works -of the Zeppelin Air Ship Construction Company. Her hull measured 446 -feet in length, had a diameter of 42½ feet, and a volume of over -half a million cubic feet. It also had a ladder running through one -of the compartments to a platform on its top. Her motors of 220 horse -power were taken uninjured from the wreck of the old _Zeppelin IV_ at -Echterdingen. - -Without previous notice this new air ship set forth in a rain on the -evening of May 29, 1909, headed toward Berlin, having on board the -Count and seven other men. The purpose of the voyage was merely to -exercise the ship; not to reach any definite goal; but by mistake she -was reported on her way to Berlin, so that the Kaiser and his retinue -waited some hours in vain to receive her. She voyaged bravely past -Nuremberg and Leipsic to Bitterfeld, within 85 miles of the capital; -then turned for home, the Count being unaware of the hopes he was -disappointing. She returned successfully past Weimar and Stuttgart, -then, near Goeppingen, descended on an open plain to take on gasoline -from a neighboring petroleum refinery. As they were nearing the ground -in a heavy rain, Count Zeppelin, who was acting as pilot, suddenly -beheld, just before them, a half dead pear tree, with gaunt bare limbs. -He gave a sharp order to starboard the helm; but his aëronaut, worn by -too long service, thrust the helm to port, and the ship, impelled by a -sudden gust, plunged head on against the tree. Her prow was wrecked, -the frame and envelope being wrenched and torn for a distance of 100 -feet. - -The disaster seemed complete, but the dauntless Count was equal to the -emergency. Twenty workmen were summoned from Friedrichshafen, sixty -miles away, and sped to the rescue in automobiles. Electric wires from -a nearby plant were stretched to furnish light for night repairs. The -grounds were guarded by police and troops. The hull was detached from -the tree; furnished with a temporary prow of young firs covered with -balloon cloth; relieved of the forward motors and other impedimenta; -furnished with fresh supplies; and, in exactly 28 hours from the -mishap, was ready for the homeward voyage. - -Slowly the crippled air ship sailed for Friedrichshafen, followed by -the white-haired inventor in an automobile, unmoved and triumphant. -A mighty shout ascended from the immense crowd of witnesses who had -assembled from many quarters. All Germany was elated and jubilant. The -great voyage and the prompt recovery from apparent disaster were a -triumph of the whole people, for they had helped their hero to build -this ship, and now participated in his victory over the spite of -fortune and the elements. The Emperor telegraphed his congratulations, -affirming his renewed confidence in the rigid system. Without further -difficulty the vessel reached her port at an easy gait of ten miles an -hour, thus completing a memorable voyage of seven hundred miles—one of -the most glorious in the history of aëronautics. - -If the citizens of Berlin were disappointed on this occasion, -they had not long to wait for an aërial visit from the wizard of -Friedrichshafen. On August 27th, at 4.45 A.M., his crew of five men -sailed for Berlin via Nuremberg and Leipsic in his sixth air ship, -his latest and largest, hurriedly finished for the Berlin voyage. -It cubed 533,000 feet, and was driven by two Daimler engines of 150 -nominal horse power each. In the afternoon they reached Nuremberg, -circled over the city and landed for the night. Starting at 2.15 next -morning they battled their way toward Leipsic against a strong wind, -and at 6.45 P.M. landed for the night at Bitterfeld, where they arrived -with a broken propeller. Here Count Zeppelin joined them. The next -morning, after a good night’s rest and some repairs, they started at -half past seven, in a dense fog, which, however, soon cleared. Finally -they arrived at Berlin at half past twelve o’clock, as the people were -returning from church. They circled over the city, to the delight of -the multitude of spectators who thronged the house tops, parks, and -thoroughfares, finally reaching the parade ground at Tegel. Here, -after saluting the Emperor, the happy navigator maneuvered before the -imperial tribune, greeted by the thunderous Hoch! Hoch! of a hundred -thousand throats, and the ringing of all the church bells of the -nation’s capital. The venerable Count was graciously received by the -Emperor and members of the royal family. After spending the day at -Berlin, the crew sailed for Friedrichshafen, about midnight, where, -after various accidents and delays, they arrived in safety on September -6th. - -In some respects this was Von Zeppelin’s crowning voyage of the year, -though effected with a hurriedly finished vessel, not yet thoroughly -adjusted. In mechanical execution this journey was equaled on many -other occasions; for those great air ships were kept in active service -and were everywhere hailed with enthusiasm. Both the Emperor and his -people were proud to number those grand cruisers among the nation’s -aërial warships. With general commendation, therefore, was received -the announcement that four large _Zeppelins_ were ordered for the use -of the German navy. And not surprising was the announcement that other -inventors were at work on designs for dirigibles of the rigid type. -The projects of these new rivals, who began to appear in 1909, are set -forth in the following account:[17] - - “Count Zeppelin, who proved that air ships have a practical - future, is no longer undisputed ‘king of the air.’ His rivals - have taken his pattern, and improved it until soon air ships - will be able to keep afloat for many days and in that case to - cross oceans. A type of this modern ship is the first Schütte - leviathan of wood and steel bracing, now nearly finished at - Mannheim. It is expected to lift its twenty-four and one-fifth - tons one and a quarter miles, because its beam is sixty feet - as compared with the forty-four feet of the _Zeppelin II_. - The car is one hundred and thirty feet long, with a cabin to - accommodate thirty passengers. The new ship displaces nineteen - thousand cubic meters, as against fifteen thousand in the - _Zeppelin III_. It is expected to carry a cargo of five to six - tons supported by ten spherical sustaining chambers, and eight - ring-shape reservoir chambers connected by a secret apparatus. - These eight reservoirs automatically receive all expanding gas - that escapes from the sustaining chambers, thus conserving the - entire supporting power. Four motors of combined five hundred - and forty horse power will drive the propellers. Expert opinion - predicts a speed of thirty-seven to forty-three miles an hour, - three miles faster than the _Gross III_, at this writing the - fastest air ship in the world. The whole enterprise is backed - by Mr. Lanz, a rich manufacturer, who is president of the - German Air-Navy League. A wooden-braced ship of equal equipment - and size, designed by the Engineer Rettich, is well under way. - - “Another rival of the _Zeppelin_, so far only projected, has - been designed by the Engineers Radinger and Wagner, and is - intended to be an advance in endurance. It should float for - fifty days without replenishing gas. It is planned to have a - rigid hull of hollow paper tubes and steel bracing and to be - thirty per cent lighter than a _Zeppelin_ built of aluminum, - in any equal size. Drum-shape compartments are to hold the - sustaining hydrogen, none of which is to be lost through - expansion by the sun, as any surplus will be compressed by - automatic pumps into the hollow tubes.[18] Having six thousand - meters less displacement than the _Zeppelin III_, it will carry - a reserve of seven hundred cubic meters of gas. Thirty-two - per cent of its weight-carrying capacity will be given up to - passengers, fuel, and baggage. Engines of two hundred and - forty-two combined horse power are expected to develop a speed - of forty to fifty miles an hour. Larger craft of the same type - would, of course, carry much heavier cargoes and have higher - speed. This type of ship, soon to be placed in the construction - cradle, is expected to cross the ocean easily with fifteen - passengers.” - -In keeping with the lively growth of these great ships was the -formation of the German aërial transportation company, with a capital -stock of $750,000, reported in _l’Aérophile_ for December, 1909. A line -of large _Zeppelins_ was to connect Baden-Baden, Mannheim, Munich, -Leipsic, Cologne, Düsseldorf, Berlin, Dresden, Essen and Frankfort. -The first two auto balloons of this line were to be the _Zeppelin -IV_ and _Zeppelin V_, to be put in commission in the spring of 1910. -The _Zeppelin IV_ was to cube 706,000 cubic feet, and carry twenty -passengers in three cars, each containing a motor. The _Zeppelin V_ was -to be constructed of a remarkably light rigid alloy “electrometal,” -and was to carry at least thirty passengers. This enterprise certainly -formed an appropriate termination to the first decade of practical auto -ballooning. - -The projected passenger line of the German Air Ship Society was -inaugurated the following summer with serene audacity and fairy-like -magnificence. The first ship employed, _Zeppelin VII_, was a huge -vessel of unusual power, speed and elegance of appointment. She was -485 feet long by 46 in diameter, cubed 690,000 feet, and carried three -engines totaling 420 horse power and competent to drive her 35 miles -per hour. Midway beneath her hull and rigidly joined to it, was a -passenger car thirty-five feet long, having a vestibule at one end, a -lavatory at the other, and five compartments between them, with seats -for twenty persons. Beyond the ends of the car were open decks leading -to the boats fore and aft containing the machinery. - -At three o’clock on the morning of June 22, 1910, with Count Zeppelin -in charge, and a dozen passengers aboard, this majestic auto balloon -sailed from Friedrichshafen up the Rhine Valley for Düsseldorf, three -hundred miles, and after a prosperous voyage of nine hours, made an -easy landing. Next morning at eight thirty she voyaged from Düsseldorf -to Dortmund, thirty-seven miles north, sailing at a general height of -one thousand feet, over some of the finest industrial parts of Germany. -Then she returned to Düsseldorf with her delighted passengers who were -all enthusiasm for the new mode of travel so auspiciously begun. Of the -thirty-two persons aboard, the majority were regular public passengers -who had paid fifty dollars each for the trip, several of them tourists -from various countries, and ten of them women. - -The maiden voyage of this first air liner was a marvel and dream -of delight to the fortunate few traveling in such celestial style. -The comforts and splendors of the service quite surpassed their -expectations. Seated in that fairy car of aluminum framing lined with -mahogany and rosewood inlaid with pearl, they looked from spacious -windows over the beautiful German landscape gliding beneath them, and -enjoyed visions fit for itinerating gods. Along the shining waters of -the Rhine, and over its castellated crags, and among its rolling hills -terraced with luxuriant vineyards, now lapped in the glory of summer, -and above stately cities murmuring with multitudinous life, they sailed -in serenest comfort and security, marveling at their own strange -career through the sky, and equally regarded with wonder by all the -inhabitants below, not to say written and read about by millions in all -parts of the civilized world. The delights of land and sea travel were -happily mingled, without their inconvenience. Neither dust nor smoke -was here, nor rattle of iron rails, nor lurching and rolling from heavy -seas. Quite otherwise. The senses were charmed with the fanning of -fragrant winds forever and uniformly blowing, with the melodious drone -of the swift propeller wheels, with the green glories of the earth and -purple splendors of the sky. When the tourist was sated with these he -could turn to his book; when tired of his chair he could stroll to and -fro in the car on a soft carpet, or along the trellised deck beyond; -when his appetite called, he could answer with the choicest food and -wine; for every convenience of an ample buffet was available. It was -all so enchanting if only practical. - -Encouraged by these trials the company announced, and hoped to make, -voyages at frequent intervals. But in this they promptly encountered -difficulties. On June 28th the _Deutschland_ started from Düsseldorf on -a four-hour cruise, with nearly a score of passengers, mostly newspaper -representatives. But she remained in the air longer than intended. -Passing Solingen she tried to reach Eberfeld, but ineffectually; nor -could she find a landing place. Toward five o’clock she was caught in -a great rising wind and carried one mile aloft like a passive balloon -in a vortex or thunderhead. Here much gas was lost by expansion, and -presently, as the ship emerged from a snow cloud in the upper vortex, -with cooled gas and hull laden with precipitation, she descended at a -terrible velocity. With crippled motive power, the vessel could not be -supported dynamically by the impact of the air against her sustaining -planes and against her canted hull, for lack of forward speed. At -length with a terrific crash she struck upon the forest of Teutoberg, -80 miles from Dusseldorf, a great tree trunk piercing the rear boat and -projecting among the terrified crew. Here the vessel lodged with her -stern and controlling gear badly wrecked, and here she was abandoned -by the passengers, with her huge hull resting on the branches forty -feet from earth. Ere long she was retrieved by a company of infantry -who sawed down the trees, dismantled the ship, and returned the parts -on railway trucks to Friedrichshafen, to be used in building another -vessel. - -Thus in both civil and military aëronautics the pioneers had to endure -many losses and grievous hardships; but the direst disasters often mark -the way to the greatest victories. - - - - - PART II - - GROWTH OF AVIATION - - - - - CHAPTER VII - - MODEL FLYING MACHINES - - -From time immemorial man has admired the aërial evolutions of -wing-gifted creatures, and aspired to imitate them. But which -evolutions should he attempt first? Which if any are practicable for -the ponderous lord of creation? The question is still pertinent. - -Nature in her bounty bewilders us with wondrous models. All about -and overhead, with exquisite art, they challenge us to float or fly. -Before the flower-bell drifts the ruby-throat, his long bill in the -honey-hearted bloom; now bulletlike he leaps through boundless space. -Why not adopt that style of locomotion? Call your rainbow equipage to -the door, and take the family forth in purple state, to the music of -melodious wheels. - -If the humming bird will not serve, look above you. There rides -the dark-winged master of aërial motion, throned like a god on the -impetuous wind. Mark his majestic sweep as all day long, with unbeating -pinion, he scours the wide plain and rugged regions of the hills, -unwearied, reposeful, deliberate; now skimming the fragrant forest, or -meadow; now scaling the precipice, or swinging above the abyss; now -soaring cloudward beyond the range of human vision. There is a model -for the ambitious and the brave! - -Or turn to mid ocean when the hurricane, shearing the tops of the -arched billows, scatters them in foam and spray over the watery chaos, -and the big ship strains in the storm. See the long-winged albatross, -white vision of joy in the darkness, careering all playfully round -the imperiled vessel, and above the monstrous waves; wheeling in glad -curves, frolicking in the face of the tempest, riding, without toil or -trepidation, the rudest[19] winds a thousand miles over the sea. What a -jocund pace for man! - -Of all the charming modes of flight now possible to us it is certain -that our ancestors could copy but one with any hope of success. Minus -motive power they could not imitate the direct flight of the homing -pigeon, much less the mid-air pause of the bumblebee floating round a -daisy. Hence there remained to them only passive flight on nonvibrant -wings. The gliding of vultures, of gulls, and of certain quadrupeds and -fishes, they could imitate with profit; but when they essayed power -flight they invariably and egregiously failed. - -The art of aviation presents two main groups of fliers. The first -comprises the various man kites, parachutes, gliding machines, soaring -machines. These may be called passive flyers, because they carry no -motive power, but ride passively on the air by the force of gravity or -a towline. - -The second group comprises the bird-like flap-wing machines, called -orthopters by technical people; the screw-lift flyers, called -helicopters; the aëroplanes, also called monoplanes, biplanes, -triplanes, according to the number of superposed main lifting surfaces; -and lastly the gyroplanes, whose sustaining surfaces may turn over and -over, like a falling lath, or whirl round and round, like a boomerang. -These all may be called dynamic, or power, flyers. The technical -names, however, are not so important, as they are numerous; for the -whole aëronautic nomenclature is in a formative, not to say chaotic, -state. We may, therefore, like Adam, name the creatures as they pass -before us for review or discussion. - -Disregarding the crude essays at human flight, recorded in the early -literature and history of many peoples, we may notice first the well -authenticated sketches of Leonardo da Vinci. His fertile mind conceived -three distinct devices for carrying a man in the air. But he and his -successors for nearly four centuries could do little more than invent. -For lack of motive power they could not navigate dynamic flyers, -however ingeniously contrived. - -[Illustration: FIG. 26.—DA VINCI’S HELICOPTER.] - -Da Vinci’s first design, as shown in Fig. 26, provides the operator -with two wings to be actuated by the power of both arms and legs, -through the agency of very ingenious harness. With this device -an acrobat could fly forward and downward, to the delectation of -a multitude; but he would have to be caught on something soft to -escape injury. Since Leonardo’s day the experiment has been tried -occasionally, with varied results, sometimes grotesque, sometimes -tragic. He doubtless realized the impracticability of an orthopter -actuated by human muscle, and yet he has had many followers. The -orthopter is still a favorite device cultivated by a few persons who -propose to work its wings by means of a gasoline motor. Doubtless the -feat is physically possible, and may be accomplished in time. - -[Illustration: FIG. 27.—DA VINCI’S PARACHUTE.] - -Da Vinci’s second flyer was a helicopter, as shown in Fig. 26. An -aërial screw 96 feet in diameter was to be turned by a strong and -nimble artist who might, by prodigious effort, lift himself for a short -time. Though various small paper screws were made to ascend in the air, -the larger enterprise was never seriously undertaken. Many subsequent -inventors developed the same project; but the fellow turning the screw -always found it dreadful toil and a hopelessly futile task. Of late -the man-driven helicopter has been abandoned, but the motor-driven one -is very much cultivated. Scores of inventors in recent years, aided by -light motors, have been trying to screw boldly skyward, and some have -succeeded in rising on a helicopter carrying one man. - -Da Vinci’s third scheme for human flight, as shown in Fig. 27, was a -framed sail on which a man could ride downward, if not upward. This -device never fails to navigate with its confiding sailor. Sometimes -he lands in one posture, again in another; but voyage he must, with -the certainty of gravitation. Leonardo is, therefore, the father -of the parachute. This, in turn, has had a varied offspring. The -common parachute, the aërial glider, the soaring machine, or passive -aëroplane, that rides the wind without motive power and without loss of -energy. - -The foregoing sketches by the great artist were made toward the year -1500, and there the science stood for nearly three centuries. Much -speculation followed, but no substantial progress. Mathematicians -proved by figures the inadequacy of the human muscle to achieve human -flight. Dreamers demonstrated the same by launching themselves from -high places, and breaking their bones on the unfeeling earth, before -unpitying crowds. Finally came the balloon, giving a new impetus to an -embryo art. - -The earliest of Da Vinci’s aëronautic ideas to be practically realized -was the parachute. The exact date of its first employment is not -exactly known. In the year 1617 Fauste Veranzio published in Venice -a good technical description of the construction and operation of -the parachute, accompanied by a clear illustration, as shown in -Fig. 28. But the first authentic account of a parachute descent of -a human being is that given by Sebastien Lenormand. This dauntless -inventor, on December 26, 1783, descended from the tower of the -Montpelier Observatory, holding in either hand an umbrella sixty inches -in diameter. A few days later he sent to the Academy of Lyons the -following description of his improved parachute, illustrated in Fig. 29: - - “I make a circle 14 feet in diameter with a heavy cord; I - attach firmly all around, a cone of linen whose height is 6 - feet; I double this cone with paper laid on the linen to render - it impermeable to air; or better, instead of linen, taffeta - covered with gum elastic. I place all about the cone small - cords, which are attached below to a wicker frame, and forming - with this frame an inverse truncated cone. Upon this frame I - place myself. By this means I avoid the ribs and handle of - the umbrella, which would add considerable weight. I am sure - to risk so little that I offer to make the experiment myself, - after once having tried the parachute with different weights to - make sure of its solidity.” - -[Illustration: FIG. 28.—VERANZIO’S PARACHUTE.] - -Previous to Lenormand’s experiments, Blanchard, the aëronaut, had -dropped small parachutes from his balloon, sometimes carrying animals, -but never a human being. For unaccountable reasons the world had to -wait fourteen years longer to see a man make the new familiar parachute -descent from a balloon. On October 22, 1797, in presence of a large -crowd Jacques Garnerin ascended in a closed parachute to a height of -3,000 feet, then cut loose. The people were astonished and appalled; -but they soon saw the umbrella-shaped canvas spread open and oscillate -in the sky with its human freight. As it was but eight yards in -diameter, it descended rapidly and struck the ground with violence, -throwing Garnerin from his seat. He escaped with a bruised foot, -mounted a horse, and returned to the starting point, where he received -a lively ovation. - -[Illustration: FIG. 29.—LENORMAND’S PARACHUTE, 1784.] - -After this experiment, parachute descents became popular the world -over, and have been repeated up to the present time substantially -without change. A slight improvement in the construction was made by -cutting away the top of the canvas, thus allowing the air to escape -sufficiently to check the oscillations; but no radical change in -the design has come into general use. It would seem easy to have -transformed the craft into a traveling parachute gliding down the sky -like a great bird on out-stretched wings. Such a device would enable -the aëronaut to sail some miles and direct his course in the air. If -fair skill had been acquired it might have hastened the advent of human -flight twenty years, so far as it is practicable without the aid of -the internal combustion motor. For two decades ago Maxim produced an -abundantly powerful steam engine; but could find no one to furnish him -a manageable glider on which to mount it. Now, indeed, such gliders are -available; but they were developed by aviators, not by balloonists, or -parachutists, who should have effected that advance many years ago. - -Curiously enough, Nature has furnished a traveling parachute which -seems never to have been imitated by man, though not difficult to -copy. It is a large two-winged seed, which when dropped in any poise, -immediately rights itself, and glides gracefully through the air. The -seeds grow on a tree in India, bearing the name _Zanonia Macrocarpa_, -and when shaken from its branches look like so many sparrows sailing -earthward in wide curves. Artificial gliders of this type are easy to -construct, and would make interesting toys. However, if man has not -copied such natural models, he has done much better, by making his -gliders concave below instead of concave upward, as are the beautiful -Indian seeds. - -An interesting model of a traveling parachute, quite as efficient as -the gauzy-winged seed, is shown in the accompanying figure. It is a -sheet of paper twenty inches long by four inches wide, having a quarter -inch strip of tin folded in its forward margin, and having its rear -margin turned upward slightly, to steer the little craft from a too -steep descent. In order to improve the stability of the paper plane, -its sides may be bent upward. The model when dropped in any attitude -quickly rights itself, and sails down a gently sloping course, the rear -margin functioning as a rudder or tail. - -[Illustration: FIG. 30.—PAPER TRAVELING PARACHUTE.] - -One of the earliest trustworthy and scientific accounts of -experimentation with an aërial glider was given by Sir George Cayley in -_Nicholson’s Journal_, in 1809 and 1810. After a careful study of the -principles of stability, he, in 1808, constructed a glider spreading -300 square feet of surface and weighing with its load 140 pounds. It -had wing surfaces slightly inclined to each other, and a tail inclined -enough to determine a gentle downward course. “When any persons,” says -Cayley, “ran forward in it with his full speed, taking advantage of a -gentle breeze in front, it would bear him up so strongly as scarcely -to allow him to touch the ground, and would frequently lift him up and -carry him several yards together. It was beautiful to see this noble -white bird sail majestically from a hill to any given point of the -plain below it, with perfect steadiness and safety, according to the -set of the rudder, merely by its own weight, descending in an angle of -about 18° with the horizon.” - -Sir George Cayley made a brave start in the science of dynamic -flight, marshaling to it all the mechanical resources of his day. He -applied the most reliable data of fluid resistance then available. He -formulated the laws of equilibrium and control of a flying machine -quite as well as any of his successors for two generations. He -estimated the propulsive power required to carry a man, and computed -the weight of the newly invented Bolton and Watt steam engine capable -of supplying that power. He even conceived the idea of burning a gas -or inflammable vapor behind a piston, thus anticipating the modern -aëronautical motor. But the project as a whole was too formidable at -that time for the genius of this one man, or of his generation of -colleagues. Sailing flight they could have practiced with profit to the -advancement of aviation, but power flight on a practicable scale had to -await the long evolution of the internal combustion engine. - -The next great advancement in the devices and principles of aviation -was made by another Englishman, and a worthy successor to Sir George -Cayley. In 1842 Mr. Henson patented the aërial equipage shown in -the accompanying illustration. It was what in present-day parlance -is called a monoplane, being in fact the first commercially planned -aëroplane known to history. As seen at a glance it consisted of a large -sustaining surface rigidly trussed and driven through the air by two -propellers actuated by a steam engine. It was to be guided up and down -by means of a horizontal rudder, and guided to the right and left by -means of a vertical rudder, seconded by a keel cloth; both rudders -being at the rear of the large plane. The machine was designed to be -launched by running down an inclined plane or track. Fuller details -of this first patent aëroplane are given in the following official -description in the South Kensington Museum of a model aëroplane -constructed by Henson and Stringfellow: - - “The model consists of an extended surface, or aëroplane, - of oiled silk or canvas, stretched upon a bamboo frame made - rigid by trussing both above and below. A car is attached to - the underside of the aëroplane to contain the steam engine, - passengers, etc. It has three wheels to run freely upon when - it reaches earth. Two propellers, three feet in diameter, - are shown with their blades set at 45°. They are operated by - endless cords from the engine. Behind these is a fan-shaped - tail stretched upon a triangular frame capable of being opened - out, closed, or moved up and down by means of cords and - pulleys. By this latter arrangement ascent or descent was to be - accomplished. A rudder for steering sideways is placed under - the tail, and above the main aëroplane a sail was to be - stretched between two masts rising from the car, to assist in - maintaining the course. When in motion the front edge of the - machine was to be raised in order to obtain the required air - support. To start the model it was proposed to allow it to - run down an incline—e.g., the side of a hill, the propellers - being first set in motion. The velocity gained in the descent - was expected to sustain it in its further progress, the engine - overcoming the head resistance when in full flight. Experiments - were eventually made on the Downs near Chard, in Somerset, and - the night trials were abandoned, as the silk became saturated - from a deposit of dew. After many day trials, down wide - inclined rails, the model was found to be deficient in stable - equilibrium for open-air experiments, little puffs of wind - or ground currents being sufficient to destroy the balance. - The actual machine was never constructed, but in 1847-48 F. - Stringfellow built a model which is supposed to be the first - flying machine to perform a successful flight.” - -PLATE XII. - -[Illustration: HENSON’S AËROPLANE.] - -[Illustration: ADER’S AËROPLANE. - -_Photo E. Levick, N. Y._] - -The creation of Henson’s flying machine at that early period is one -of the most original and fruitful achievements in the century-long -development of the modern aëroplane. Barring the torsional wing-tips -invented more recently, it hardly differs in principle from the -successful monoplane of to-day. The same mode of propulsion, the same -mode of sustention, the same mode of launching and lighting, the same -mode of steering and control. What has been added since is not so much -original invention as perfection of detail through the combined efforts -of many designers. After Cayley, Henson, as nearly as any one person -was the inventor of the flying machine. He did not bring his conception -to practical maturity, nor was that to be expected; but he did lay -down the broad lines which have led others to success. His ideas still -feature every practical aëroplane, and particularly every successful -monoplane. Indeed, it is now possible to construct an aëroplane from -Henson’s description that will fly, even in breezy weather, with -a stability practically as good as that of the early Voisin and -Antoinette machines before the use of the aileron or torsional wing was -practiced. It is all a question of wise proportioning and sufficient -motive power. - -So much for Henson’s contrivance as an abstract invention. The -concrete, full scale machine was to spread 6,000 square feet of -surface, weigh 3,000 pounds, and be propelled by a high pressure steam -engine of 25 or 30 horse power. The machine was not completed on a -large scale, and wisely so; for it was inadequately powered, and, -moreover, required many refinements of detail to make it entirely -practical. These improvements had to be left to succeeding inventors -with accumulated experience and resources. - -In 1844 Mr. Henson began the construction of a steam-driven model, -in partnership with his friend, Mr. Stringfellow, who designed the -motor for it. They experimented together for some weeks with only -meager success, but gaining valuable experience. A model of the -Henson-Stringfellow machine is on exhibition at the South Kensington -Museum. - -In 1846 Stringfellow built a steam model aëroplane about the size of a -large soaring bird, and weighing all together, with fuel and water, 6½ -pounds. A special feature of this model was that its main surfaces were -sloped like the wings of a bird, _slightly concave below and feathered -toward the back_; thus making it more efficient and stable in flight. -With a good head of steam, and propellers whirling, the model ran down -a stretched wire, leaped into the air “and darted off in as fair a -flight as it was possible to make, to a distance of about 40 yards.” -Thus the first power-driven aëroplane to fly successfully was the -little steam model constructed by Stringfellow in 1846. - -[Illustration: FIG. 31.—WENHAM’S AËROPLANE, 1866.] - -In 1866, two decades after the flight of Stringfellow’s monoplane, -Mr. F. H. Wenham, another Englishman illustrious in the annals of -aëronautics, patented the multiplane; that is, an aëroplane comprising -two or more superposed surfaces. This proved to be a valuable -contribution to the art of aviation, and continues in use at the -present time. The device furnished an increase of sustaining surface -without enlargement of the ground plan. It moreover lends itself -conveniently to a strong and simple trussing of the surfaces. Some -designers protest that superposed surfaces blanket one another; but the -advantages just named seem amply to compensate for this objectionable -feature. If the surfaces be properly spaced, very little interference -is found; moreover, any blanketing that may occur diminishes the drift -as well as the lift,[20] though not necessarily in the same proportion. - -Wenham’s aëroplane is illustrated in Fig. 31. The rider lies underneath -the multiple wings, so as to diminish the resistance to progression -through the air. The apparatus could thus be used as an aërial toboggan -for coasting down the atmosphere. To prolong the flights two flappers -actuated by a treadle were to be employed, their ends being hinged at -a point above the operator’s back. Though the device was patented, no -very serious efforts were made to operate it practically. Once, indeed, -the inventor took his glider to a meadow and mounted it, during a lull -in the evening wind, but soon a gust caught him up, carried him some -distance from the ground and toppled him over sidewise, breaking some -of the surfaces. The machine disclosed some good working principles; -but it was inadequately ruddered, and too feebly constructed, to -weather the buffets of the prevailing ground currents. - -PLATE XIII. - -[Illustration: STRINGFELLOW’S AËROPLANE (FRONT). - -(Courtesy Smithsonian Institution.)] - -[Illustration: STRINGFELLOW’S AËROPLANE (SIDE). - -(Courtesy Smithsonian Institution.)] - -Adopting the scheme of superposed surfaces then recently devised -by Wenham, Mr. Stringfellow in 1868 constructed the interesting -steam-driven model shown in Plate XIII. This consists essentially of -three superposed planes, rigidly connected by rods and diagonal wires, -propelled by a pair of screws actuated by a high pressure steam engine, -and guided by a tail. The three planes aggregated 21 feet in length and -28 square feet in surface; totaling, with the tail, 36 square feet. -The engine was rated at one third of one horse power. Its weight is -not known, but may be roughly surmised from the fact that a separate -engine exhibited simultaneously by Stringfellow weighed thirteen pounds -per horse power. The model was entered for competition in the London -Aëronautical Exhibition of 1868. In actual operation, however, it seems -not to have excelled the monoplane of 1846; but still it is of much -interest as being the prototype of the multiple-wing aëroplane now in -common use. It seems to have been the first aëroplane having two or -more sustaining surfaces joined by rods and stayed by diagonal cords -after the manner of a Pratt truss. This historic little model was -purchased by Professor Langley for the Smithsonian Institution, and -is now to be seen suspended from the ceiling of the National Museum, -beside Langley’s own models and Lilienthal’s epoch-making glider. - -[Illustration: FIG. 32.—PENAUD’S AËROPLANE TOY, 1871.] - -In 1871 M. A. Penaud produced the interesting toy aëroplane shown in -Fig. 32. The model is propelled horizontally forward by a single screw, -actuated by twisted rubber, and is fastened, as shown, to the middle of -a long stick or backbone. The center of mass of the machine is well to -the front, tending to plunge the model earthward like a heavy-headed -arrow; but this down-diving is promptly checked by the tiny rudder -which is so inclined as to counteract the diving proclivity. That is -to say the rudder dips so as to receive the aërial impact on its upper -surface; which impact increases with the speed of flight and causes -the bow to rise, until the weight before the wings just balances the -impact on the rudder at the rear. The equilibrium is thus automatic, on -the principle expounded by Sir George Cayley sixty years earlier. This -quaint little bird when liberated in the Garden of the Tuileries flew -a distance of 131 feet in eleven seconds, much to the delight of some -members of the French Society for Aërial Navigation. It may be added -that Penaud, who was a most promising and clever aëronautical inventor, -contemplated a twin-screw monoplane large enough to carry two men, but -died in his early manhood, before the project could be realized. - -[Illustration: FIG. 33.—TATIN’S AËROPLANE MODEL, 1879.] - -In 1879 M. Victor Tatin made some very promising tests with the model -shown in Fig. 33, so promising, in fact, as to convince many that human -flight was even then practicable. This little flyer was a twin-screw -monoplane mounted on wheels, and actuated by an oscillating compressed -air engine, the whole machine weighing 3.85 pounds, and supported by a -silk plane measuring 16 by 75 inches. The central body of the aëroplane -was a thin steel tube three feet long by four inches in diameter -containing the compressed air, and weighing only one pound and a half, -though strong enough to endure a pressure of twenty atmospheres. When -the model was allowed to run round a board walk 46 feet in diameter, -tethered to a stake at the center, it quickly acquired a speed of 18 -miles an hour, rose in the air, and flew a distance of fifty feet. - -A remarkable deduction from the very careful measurements made with -this machine was that it carried at the rate of 110 pounds per tow line -horse power, when flying at an angle of 8 to 10 degrees. Mr. Tatin -concluded: “These experiments seem to demonstrate that there is no -impracticability in the construction of a large apparatus for aviation, -and that perhaps even now such machines could be practically used in -aërial navigation. Such practical experiments being necessarily very -costly, I must to my great regret, forego their undertaking, and I -shall be satisfied if my own labors shall induce others to take up such -an enterprise.” - -Tatin’s faith in the practicability of a large aëroplane was later -voiced by Mr. Chanute in his valuable book, _Progress in Flying -Machines_, published in 1894, but now unfortunately out of print. -Recalling that Maxim had recently produced a large motor weighing -complete only ten pounds per horse power, he says: “Aviation seems to -be practicably possible, if only the stability can be secured, and an -adequate method of alighting be devised.” Since the above quoted facts -and opinions were published, no competent man well informed in the -science of aviation has for one moment doubted the feasibility of human -flight. - -[Illustration: FIG. 34.—HARGRAVE’S MODEL SCREW MONOPLANE, 1891.] - -In 1891, twelve years after Tatin’s experiment, Lawrence Hargrave, of -Sydney, Australia, made a similar compressed air monoplane, with a -single-screw propeller, but without wheels for launching and lighting. -The model, which is shown in Fig. 34, had a wing-spread of 20 square -feet, weighed about three pounds, and flew 128 feet in eight seconds. -The weight carried was at the rate of 90 pounds per horse power, a very -encouraging result. Two years later he described a small steam engine -which he had developed, weighing 10.7 pounds per horse power, and -capable of driving the model about two miles, though he did not use it -for that purpose, being engrossed with other researches. - -One interesting outcome of his numerous experiments was the Hargrave -Kite, now more familiarly known as the box kite. A good example of -his kites is the type shown in Fig. 35. This consists of two arched -biplanes mounted tandem on a backbone, or connecting framework. The -kite floats steadily, and was thought suitable for the body of a flying -machine to be driven by an engine and propeller. Thus meteorology is -indebted to aëronautics for its most useful kite. - -[Illustration: FIG. 35.—HARGRAVE’S KITE.] - -A very novel and interesting type of aëroplane model was tested by -Mr. Horatio Phillips in 1893. After careful preliminary experiments -with various forms of curved “sustainers,” or lifting surfaces, tested -in a wind tunnel, to determine which were most suitable wing forms, -he finally constructed the flying apparatus shown in Plate XIV. This -consisted of a compound aëroplane composed of many superposed narrow -curved slats, the whole resembling an open Venetian blind. These -curved blades, or sustainers, measured 12 feet long, 1.5 inches wide, -2 inches apart, and were held in a frame sharpened to cleave the air -with slight resistance. The entire aëroplane spread 136 square feet -of lifting surface, and was mounted on a truck as shown, carrying a -steam engine and boiler, to actuate a two blade propeller 6 feet in -diameter. The whole apparatus weighed 330 pounds, to which a dead load -was usually added, and ran around a circular wooden track 628 feet in -circumference, being tethered at the center, as in Tatin’s experiment. -The apparatus readily lifted itself, when running at a speed of 28 -miles an hour, and carried at the rate of 72 pounds per horse power, -the added load weighing at times nearly one fourth that of the machine -itself. The ultimate purpose of the experiment was to prepare the -way for a one-man aëroplane like that shown in the lower part of the -figure. This latter model actually carried a man across a field in -1904, but was found defective in longitudinal balance, because perhaps -of its inadequate horizontal rudder. Apparently Mr. Phillips had in -1904 a machine capable of well-balanced flight, if he had made the -rudders large enough, and provided a mechanism for rotating the slats -at either wing end, so as to control the lateral poise, as proposed by -the present writer in 1893, for practically that same flier (see page -229). - -Phillips’s aëroplane shows a distinct advance over its predecessors, -even Wenham’s multiplane, because of the careful curving of the -sustainers. Tatin’s flat wing machine had, indeed, shown a greater -efficiency as a whole, but that was likely due to less proportionate -body resistance. To Phillips we owe the introduction of superposed -arched surfaces, now so commonly used in mechanical flight. Whether he -was wise in using so many narrow wings, instead of a few broad ones, -was a question to be answered by precise measurement. - -Prof. S. P. Langley, like Mr. Hargrave, made numerous flying models, -trying, in turn, the power of twisted rubber, compressed air and -steam. He constructed scores of gauzy winged contrivances which -flitted about like huge butterflies or birds, till their mission -was accomplished—that of illustrating a scientific principle to his -inquiring mind. One by one they came into existence, enjoyed an -ephemeral life, and then were consigned to the aëronautical attic of -the Smithsonian Institution, a storehouse of quaint flying creatures. -It was a most interesting collection which well merited preservation -as the “juvenile” creations of an illustrious man. But the first -experiments of Langley, like the similar ones of Hargrave, were of -value chiefly as training to the inventor himself; they were not -important advances in the art of aviation. Such advances were to follow -the long preliminary training. - -PLATE XIV. - -[Illustration: PHILLIPS’ TETHERED AËROPLANE.] - -[Illustration: PHILLIPS’ AËROPLANE.] - -On May 6, 1896, Dr. Langley launched the picturesque steam model, -which, to his mind, first proved conclusively the practicability of -mechanical flight. It was the crowning success, and, as he thought -then, probably the termination of his aëronautic labors. “I have -brought to a close,” says he, “the portion of the work which seemed -to be peculiarly mine—the demonstration of the practicability of -mechanical flight—and for the next stage, which is the commercial -and practical development of the idea, it is probable that the world -may look to others. The world, indeed, will be supine if it does not -realize that a new possibility has come to it, and that the great -universal highway overhead is now soon to be opened.” - -As shown in Plate XV, Langley’s first successful steam flying machine -is a tandem monoplane[21] with twin screws amidships. It measures -nearly 13 feet from tip to tip of its wings, about 16 feet along its -entire length, and weighs with motor and propellers 30 pounds. The -boiler weighs 5 pounds, the engine 26 ounces, and the power developed -was between 1 and 1.5 horse power. The model is therefore somewhat -larger than a large condor, and very much more powerful. - -Being too small to carry a pilot, it was launched over water, to -obviate wreckage on landing. The machine was capable of flying several -miles continuously, but in the actual test on the Potomac River the -flight was limited, in order to prevent the model passing beyond -the shore. The flyer was placed on launching ways on the top of a -houseboat, hurled rapidly forward by force of a spring, and liberated -in space, with engine and propellers running at full speed. Its -subsequent behavior has been graphically described by an eyewitness, -Dr. Alexander Graham Bell, in the following passage, published in -_Nature_, May 28, 1896: - - “On the occasion referred to, the aërodrome, at a given signal, - started from a platform about 20 feet above the water, and - rose at first directly in the face of the wind, moving at all - times with remarkable steadiness, and subsequently swung around - in large curves of perhaps a hundred yards in diameter, and - continuously ascending till its steam was exhausted, when at - a lapse of about a minute and a half, and at a height which - I judged to be between 80 and 100 feet in the air, the whole - ceased turning, and the machine, deprived of the aid of its - propellers, to my surprise did not fall, but settled down so - softly and gently that it touched the water without the least - shock, and was in fact immediately ready for another trial. - - “In the second trial, which followed directly, it repeated in - nearly every respect the actions of the first, except that the - direction of its course was different. It ascended again in the - face of the wind, afterward moving steadily and continually in - large curves, accompanied with a rising motion and a lateral - advance. Its motion was, in fact, so steady that I think a - glass of water on its surface would have remained unspilled. - When the steam gave out again it repeated for a second time - the experience of the first trial when the steam had ceased, - and settled gently and easily down. What height it reached at - this trial I can not say, as I was not so favorably placed as - in the first, but I had occasion to notice that this time its - course took it over a wooded promontory, and I was relieved of - some apprehension in seeing that it was already so high as to - pass the tree tops by 20 or 30 feet. It reached the water in - one minute and thirty-one seconds from the time it started, at - a measured distance of over 900 feet from the point at which it - rose. - -PLATE XV. - -[Illustration: LANGLEY’S STEAM MODEL. - -(Courtesy Smithsonian Institution.)] - -[Illustration: LANGLEY’S GASOLENE MODEL. - -(Courtesy Smithsonian Institution.)] - -[Illustration: LANGLEY’S TWO SURFACE GASOLENE MODEL. - -(Courtesy Smithsonian Institution.)] - - “This, however, was by no means the length of its flight. I - estimated from the diameter of the curve described, from the - number of turns of the propellers, as given by the automatic - counter, after due allowance for slip, and from other measures, - that the actual length of flight on each occasion was slightly - over 3,000 feet. It is at least safe to say that each exceeded - half an English mile. - - “From the time and distance, it will be noticed that the - velocity was between 20 and 25 miles an hour, in a course - which was constantly taking it ‘up hill.’ I may add that on a - previous occasion, I have seen a far higher velocity attained - by the same aërodrome when its course was horizontal. - - “I have no desire to enter into detail further than I have - done, but I can not but add that it seems to me that no one who - was present on this interesting occasion, could have failed to - recognize that the practicability of mechanical flight had been - demonstrated.” - -In passing it may be added that in 1899 this model was again flown -successfully, having superposed surfaces; for its inventor all along -recognized the structural advantage of the bridge trussing in biplanes. -If he preferred the monoplane, or single-tier arrangement, it was -because the best flights were obtained with such models. - -Many persons now thought that Langley would do well to rest on his -laurels, leaving to others the “commercial and practical development” -of his ideas. But he had caught the aëronautic fever. Like many another -poor son of fancy, he was haunted by magnificent dreams. Now, perhaps, -was stirring in his mind that vision of his childhood when he lay on -his back in the New England pasture and “watched a hawk soaring far -up in the blue, and sailing for a long time without any motion of its -wings, as though it needed no work to sustain it, but was kept up there -by some miracle.” Mr. Andrew D. White declares that Professor Langley -was a poet by nature. Whatever the dominant impulse, he followed his -“aërodrome” like one possessed. It was the all engrossing pursuit of -the latter years of his life, entailing how much vexation, toil and -unjust censure! - -In 1898 the Board of Ordinance and Fortification, after carefully -studying the flights of 1896, appropriated $50,000 to enable Professor -Langley to build a one-man flyer. He first tested a gasoline driven -aëroplane having one fourth the linear dimensions of the man-carrying -one. In external appearance this model resembled the steam “aërodrome,” -described above, but was considerably larger. It spread 66 square feet -of surface, weighed 58 pounds, and developed 2½ to 3 horse power. -When ready for the test, August 8, 1903, this beautiful white-winged -creature was taken to the middle of the Potomac, 40 miles below -Washington, mounted on the launching ways, swiveled into the eye of -the wind and shot forth like a stone from a catapult, her engine and -propellers humming merrily. - -The flight must have been very graceful and dignified, for it -elicited commendation even from the squad of reporters present, men -who customarily recorded such events with uncontrollable mirth and -ridicule. Dr. Langley merely remarks: “This was the first time in -history, so far as I know, that a successful flight of a mechanically -sustained flying machine was seen in public.” It was also the first -successful gasoline[22] aëroplane, and the forerunner of the host -of flyers presently to spring up in all parts of the world. Its -flight though very brief, owing to a surcharge of gasoline, was so -satisfactory in all its dynamic features, that it seemed to justify an -immediate launching of the one-man machine, with which like maneuvers -were anticipated. As will appear in the sequel this prospect of fair -sailing was beset with unsuspected shoals. - -We have now traced the growth of the aëroplane from its earliest -conception to the present time, as exemplified by working models. First -came the parachute of Da Vinci and others, whose sole function was -to carry a weight softly to earth, with no provision for steadiness -of motion, or control of direction. Then, in the beginning of the -nineteenth century, arrived the gliders adjusted for steadiness, -equilibrium and a predetermined slanting course in the air; beautiful -passive birds, actuated by gravity, but riderless and awaiting the -advent of artificial motive power. Then suddenly appeared Mr. Henson’s -wonderful _project_; a large man-carrying aëroplane, provided with -a motor, propellers, rudders, wheels for launching and landing—an -impossible scheme for that day, but destined to be realized in -the course of two generations. Henson’s idea was doubtless the -most prolific in the history of aviation. After this followed the -numerous instructive models, actuated by twisted rubber, steam, -gasoline, compressed air—economic contrivances for ascertaining the -secrets of propulsion, equilibrium and control, of the prospective -man-flyer. These may be said to have demonstrated the practicability -of man-flight, though many contemporaneous and allied experiments, to -be noticed presently, all contributed to the triumphs subsequently -achieved by the race of sanguine, daring and tireless inventors. - -[Illustration: FIG. 36.—LAUNOY AND BIENVENU’S HELICOPTER, 1784.] - -In this brief outline, the two other main types of flyers, the -orthopters and helicopters, have been omitted. The orthopters, or wing -flapping machines, have been very numerous, but have not yet approached -practical success in use. Though a man-carrying orthopter has not yet -been produced, an elegant pigeon-like model operated by rubber has been -made by Pichancourt, which flies and balances nicely. The helicopters, -or direct-lifting screws, have more than once raised their weight and -that of the helicoptrist, or navigator. These latter, therefore, seem -to be of sufficient interest to merit a short historical review. - -Leonardo da Vinci, the fertile pioneer in aviation, missed one novel -device worthy even of his genius. He constructed aërial screws of -paper, but he did not endow them with motive force. Such an achievement -was in his power, and would have ranked him with Archytas of Tarentum, -who 400 B. C. invented the kite, and an artificial dove said to have -flown, no one knows how. Having escaped Da Vinci’s ingenuity, the power -helicopter failed to materialize for three centuries, but finally -appeared in France. - -In 1784 Launoy and Bienvenu, the first a naturalist, the second a -mechanician, exhibited before the French Academy the interesting toy -shown in Fig. 36. This was the first power-driven helicopter, and is -said to have lifted itself in the air quite readily. As may be observed -it consists of two coaxial screws rotating in opposite directions -actuated by the power of an elastic stick, like a bow. The screws were -each about one foot in diameter and made of four feathers; one screw -being fastened to the top of the rotating shaft, the other fastened -to the bow, which rotated in the contrary direction. The little model -excited much interest, particularly as its inventors expected to build -a man-carrying helicopter on the same plan. The larger project was -obviously without merit; for no combination of springs can maintain -flight for more than a few seconds even on the most favorable scale. - -A more powerful toy helicopter was produced by Mr. Horatio Phillips in -England in 1842. This was a single aërial screw emitting jets of steam -which compelled it to spin, on the principle of a lawn sprinkler, or -a Hero engine. The whole apparatus weighed two pounds, and had screw -blades inclined 20° to the horizon. The steam was generated by the -combustion of charcoal, niter and gypsum, as in the fire extinguisher -previously invented by the same ingenious man. The performance of this -curious helicopter, is thus described by Mr. Phillips: “All being -arranged, the steam was up in a few seconds, then the whole apparatus -spun around like a top, and mounted into the air faster than any -bird; to what height it ascended I have no means of ascertaining. The -distance traveled was across two fields, where, after a long search, I -found the machine minus the wings, which had been torn off from contact -with the ground.” - -“The distance traveled was across two fields.” For vagueness this -surpasses the poet’s measure—“as far as oxen draw the plow in a day.” -It would be most interesting to have an exact description of this -classical experiment, when for the first time a flying machine rose -in the air propelled by a heat motor. It would be desirable also -to know the possibilities of such a helicopter, particularly since -Prof. Cleveland Abbe has proposed to employ a like agent to carry -meteorological instruments into the higher atmosphere.[23] - -[Illustration: FIG. 37.—FORLANINI’S HELICOPTER, 1878.] - -A still more ambitious helicopter was that shown in Fig. 37 invented by -Professor Forlanini, an Italian Civil Engineer, and launched in 1878. -The lower screw was fastened to the frame of a steam engine, the upper -screw was attached to the crank shaft. Steam was supplied from the -globe shown beneath, which was two thirds filled with water, and well -heated over a separate fire just before an ascension. As the globe was -merely a reservoir of hot water and steam, carrying neither fuel nor -furnace, its power waned rapidly. The best flight lasted about twenty -seconds, attaining a height of 42 feet. The apparatus weighed 77 -pounds, spread 21.5 square feet of screw surface, and lifted about 26.4 -pounds per horse power. - -Many other helicopter models have been tried from time to time, with -various sources of power, without, however, yielding any important -results beyond those already given. But these were sufficiently -encouraging. If a large machine could be made to lift as many pounds -per horse power, it would be easy to build one competent to carry -a man. That, indeed, has been done on several occasions. Of the -various inventors who have built man-lifting helicopters M. Cornu and -M. Bréguet, in France, seem to have been first to attain a measure -of success. While their machines have raised a passenger directly -from the ground, they have not yet maneuvered in horizontal flight -with sufficient speed to be of practical service. However, a few -helicoptrists in various countries are still industriously at work, and -hope eventually to rival the aëroplanists in the mastery of flight. -There will doubtless be room in the sky for both. Perhaps also there -will be occupation and a mission for both. - - - - - CHAPTER VIII - - NINETEENTH CENTURY MAN-FLYERS - - -Having traced the growth of winged models from their earliest beginning -to the time when they proved the possibility of mechanical flight, we -may now study the evolution of larger machines, designed to carry human -beings. Considering first the aëroplane, we may follow the two general -methods advocated by various inventors for launching a man safely in -the air, both of which led to success. The first of these may be called -Henson’s method, the second Lilienthal’s, coupling them with the names -of their distinguished pioneer exponents. Henson in 1842 proposed -that the pilot should mount a full-power machine, run along a smooth -course, and glide into the air without previous experience in the art -of navigating. Lilienthal recommended careful preliminary training on a -glider, by which the novice should acquire sufficient skill in parrying -the wind to qualify him to manage a dynamic machine, under its more -complex conditions of control. Others, more cautious still, contended -that automatic equilibrium should be secured before a rider risked his -bones on the aërial bronco; while still others thought the uncertain -beast should be tethered to some point in the sky, say a balloon or -taut wire, or the end of a pole; so that however he bucked, or reared, -he should not fall over on his rider. - -We have noticed in the first chapter some picturesque man-flights, -usually deplorable or tragic; and always fruitless for lack of -scientific method in experimentation and report to the world. There can -be no doubt that such flights were accomplished, mainly, of course, -by the aid of gravity; but the difficulty is to ascertain the exact -nature of any given performance, the specifications of the apparatus, -and the principles of equilibrium and control. Gradually, however, the -experimenters improved both in the construction of man-carrying devices -and in the manner of imparting their results to their colleagues, or -successors; and so the flying enterprise began to assume a progressive -aspect, attended with that scientific dignity which invests secure -and continuous advance in any branch of knowledge. Little of value, -however, can be gleaned from any such flights made prior to the middle -of the nineteenth century. From that time forward observers and -inventors made definite and fairly methodical efforts to develop the -art of gliding and soaring in the air, the first fruit of which was to -hasten the advent of the modern aëroplane. - -A French novelist and aëronautic writer, G. de la Landelle, relates -an amazing adventure in the art of soaring, which may have some -foundation in fact, though savoring strongly of fiction. An experienced -sailor, Captain Le Bris, having observed the albatross soaring without -wing-beat, determined to imitate the fascinating flight of that -limber-winged spirit of the sea. To such end he built the bird shown in -Fig. 38, a ninety-pound albatross, with arched wings fifty feet across -and articulated to the boat-like body. In this the brave aviator would -stand upright, turn the wings and tail to maintain his balance, and -steer grandly through the sky. Placing this long-winged creature across -a cart driven by a peasant, he stood erect and headed against a breeze; -the wings set low to prevent lifting till an opportune moment, and the -bird held down to the car by a rope which the captain could quickly -release. When the horse was a-trot, and the wind blowing freshly, Le -Bris raised the front edges of the wings. Thereupon the albatross -tugged upward, and the mooring rope was slipped, but accidentally -whipped around the driver’s waist. The horse galloped away with the -cart; the bird, with the exultant sailor on its back, soared 300 feet -into the air, and incidentally carried up the peasant, dangling at -the end of the rope and howling with fright. Noting the distress of -his passenger, the kindly captain sailed close to earth, so that the -peasant might disembark and run to his horse, meaning then to hie away -for a long cruise in the clouds. But with this change of weight the -vessel seemed not to navigate well; so she was brought skimming to -land, with no mishap save a slight damage to the advancing wing, which -broke as it touched the ground. - -[Illustration: FIG. 38.—LE BRIS’ AËROPLANE, 1855.] - -Having repaired the great bird’s wing, Captain Le Bris next made -a launching from the arm of a derrick, 30 feet above the ground, -overlooking a quarry 70 feet deep. The attendant swains stood -open-mouthed, wondering whether this madman would overleap the clouds, -or promptly butt out his brains on a jagged rock. When the wind blowing -from the quarry seemed to float him in perfect poise, he tripped the -suspension hook, and headed for the precipice on even keel. He was now -happily launched, and keen for an aërial journey; but after passing -the brink, he seemed to encounter an eddy which tilted his craft -forward. The vessel dipped and rose; the captain plied his levers, -turning now the tail, now the pinions. He crossed safely over the -invisible breakers, and reached the quiet air of the quarry on level -wing. But now his forward speed was lost, the great bird sank rapidly -and crashed upon the rocky bed below. The wary seaman anticipating a -bump, sprang upward to soften his fall; but a lever rebounding from the -shock, hit one of his legs and broke it. - -Some twelve or thirteen years later, in 1867, Le Bris, aided by a -public subscription at Brest, built a second albatross, with which -he made a number of small flights, sometimes riding it himself, and -sometimes replacing his weight by ballast. On one occasion the loaded -bird, held by a light line, rose 150 feet and advanced against the -wind. Suddenly the sailors holding the line observed it slacken, and -saw with amazement the long-winged creature soar forward 600 feet, as -stately and serene as its living prototype. Presently encountering a -sheltered and quiet region of air before some rising ground, it settled -softly to earth in perfect equipoise. But on a subsequent launching -from the same favorable ground, the dumb creature pitched forward and -plunged to the earth where it lay shattered and torn in a hopeless -tangle. Le Bris looked on the wreck in despair, surveying sadly the -remains of his once cherished bird; then sat upon the débris a long -time, his head between his hands, his heart broken, his mind tortured -with anguish. Impoverished, chagrined, derided, he now must abandon -the albatross business. Five years later this intrepid sailor of sea -and air was killed by some ruffians, in 1872, while a constable in his -native place, and after a period of honorable service to the state in -the Franco-Prussian War. - -The story is more romantic than instructive, for want of exact data. -To give the experiments their proper value to others, fuller details -of the mechanism should be furnished, and adequate measurements of the -speed and direction of the aërial currents. At one time the sailing -was even, at another, rough, though outwardly the conditions appeared -the same. Apparently the successful flights occurred when the bird was -launched to windward from rising ground, that is, when the current had -an upward slant, to exert a propulsive effort. This species of soaring -has been observed frequently in nature, and has been imitated both with -models and with man-carrying gliders. Nevertheless Le Bris’ experiments -were very remarkable for the time, and, if adequately reported, might -have proved to be of much interest and value to aëronautical science. - -Another Frenchman alert to the glory of aërial motion was L. P. -Mouillard, the poet-farmer of Algeria. From boyhood he studied the -birds with unabated interest and pleasure. He would journey miles to -attend the “morning prayer” of the starlings in the forest of Baba-Ali; -noting, just before sunrise, how their melodies suddenly hushed, and -the forest seemed to bound upward, and heaven filled with the music of -innumerable wings. He would time the shadow of the high bird of passage -riding the hurricane from continent to continent. He saw the tyrant -eagle fold his wings in mid air and plunge a thousand feet in ferocious -swoop after the swift-fleeing duck or rabbit. He loved to watch the -great tawny vulture on the mountain top shake the dew from his vast -plumes, straddle the morning wind, and all day long, with never a beat -of those grand pinions, soar godlike through immensity, the marvel -and delight of the nether world. When the electric wind of the desert, -blowing from Central Africa, brought the big scavengers and noble birds -of prey, he sat on the ground scrutinizing their majestic flight and -planning to imitate it. He would lie in ambush where the silent-rowing -owl darted at dusk through the timber, fierce and swift as the eagle; -a dreadful thing, with its night piercing eyes, its big ears and beak, -its horrid talons, its sudden shriek startling the forest with ominous -echoes. No feature escaped him, and least of all an aërodynamic one. - -For thirty years he continued these studies. He would bring home -the birds, lay them on their backs and mark their contour on paper, -measure their projected area, weigh and compare them. He formulated -curious conclusions about sailors and rowers, the functions of tail and -quill feathers, weight and wing-spread, bulk, agglomeration of mass, -resistance and velocity. He notes that only massive birds soar well, -the broad-winged ones requiring a moderate wind, the narrow-winged ones -requiring a gale, and sailing with perfect ease in a tempest; and he -concludes that man may imitate both types. His book[24] is replete with -charming anecdotes, observations and quaint theories, interesting alike -to ornithology and aviation. - -But Mouillard did more than theorize; he built soaring machines and -soared a little. His third and best glider, illustrated in Fig. 39, was -a tailless monoplane made of curved agave sticks screwed to boards, -and covered with muslin. The aviator, standing in the open space C, -harnessed the plane on with straps looped round his legs and shoulders, -and fastened to the points D D. His forearms, passing under straps, -rested on the board, enabling him to tilt the whole by shifting his -weight. In order to vary the dihedral angle between the wings, they -were hinged together and actuated by rods running from the man’s feet -to the ends of the boards, hardly as far out as the center of wind -pressure, thus apparently stressing his legs like a wishbone. - -[Illustration: FIG. 39.—MOUILLARD’S AËROPLANE.] - -He now sent the home folks away from the farm, buckled on his wings and -walked along the prairie road waiting for a breeze. The road was raised -five feet above the plain and bordered by ditches ten feet wide. His -wings felt light; he ran forward to test their lift, and he thought to -amuse himself by jumping the ditch. The result is thus expressed in his -own words:[25] - - “So I took a good run across the road and jumped at the ditch. - But, oh, horrors; once across the ditch my feet did not come - down to earth; I was gliding on the air, and making vain - efforts to land; for my aëroplane had set out on a cruise. I - dangled only one foot from the soil, but, do what I would, I - could not reach it, and I was skimming along without the power - to stop. At last my feet touched the earth; I fell forward - on my hands; broke one of my wings, and all was over; but - goodness, how frightened I had been! I was saying to myself - that if even a light wind-gust occurred, it would toss me up - 30 to 40 feet into the air, and then surely upset me backward, - so that I would fall on my back. This I knew perfectly, for I - understood the defects of my machine. I was poor, and I had not - been able to provide myself with a more complete aëroplane. - All’s well that ends well. I then measured the distance between - my toe marks, and found it to be 138 feet. - - “Here is the rationale of the thing. In making my jump I - acquired a speed of 11 to 14 miles per hour, and just as I - crossed the ditch I must have met a puff of rising wind. It - probably was traveling some 8 to 11 miles per hour, and the - two speeds added together produced enough pressure to carry my - weight.” - -He repaired his wing and repeated the test a few days later. A violent -wind gust came; picked him up from the earth, and whelmed him over. In -his alarm he allowed his “wish-bone” to spread, and the wings to fold -up like those of a butterfly at rest, pinching him between them like -a nut in a nutcracker. One wonders whether the overwheeling vultures -witnessed this gentleman’s flight with any sense of humor. - -After mature reflection, Mouillard concluded that he should give his -aëroplane a rudder, and flex the wings, in order to insure adequate -control. But here he halted, being a poor man unskilled in the art -of construction. He had reached the limit of his endowments. He had -observed faithfully and described charmingly the wonderful flights -of various birds; but he must leave to his technical successors the -pleasure of imitating or excelling those extraordinary maneuvers—leave -them the pleasure, the sacrifice, the long years of toil and danger, -accompanied perhaps by indiscriminate applause or derision. - -In the meantime another distinguished disciple of the birds was -energetically at work in Germany. No less ardent than Le Bris, or -Mouillard, Otto Lilienthal was far better equipped and circumstanced. -He was a graduate of the Potsdam Technical School, and a student -for three years in the Berlin Technical Academy. He was engaged in -practical construction ten years in various machine shops at Berlin. -After 1880 he operated a flourishing machine factory of his own. From -boyhood he with his brother Gustavus had carefully studied the flight -of birds, and had made numerous experiments in aviation. On moonlight -nights in their little home place of Anclam, in Pomerania, the boys -would run downhill, flapping their home-made wings, like Dædalus and -Icarus, but with no other danger than discovery and teasing by their -neighbors. At Potsdam and Berlin they continued to experiment and to -construct wings of increasing size and power. Thus Otto Lilienthal -reached early manhood thoroughly trained by his long courses in the -technical schools and shops, brimming with well pondered ideas, -strengthened by continuous observation and experiment, and in financial -circumstances which permitted him to devote time and money to the -unremunerative pursuit of aviation. To this may be added that his -mature years were cast in a time when the allied sciences could aid -him far more than they had aided his predecessors of the preceding -generation. - -After careful research for the most efficient form of alar surface, -Lilienthal resolved to imitate the birds. First he would build a pair -of arched wings, and learn to coast down the atmosphere, balancing -and steering like a stork in the gusty and treacherous current. He -would thus acquire the pilot’s skill, and ascertain the towline power -required to sustain a given weight. Then he would add a suitable -propelling mechanism, test it cautiously, and acquire the mastery of -dynamic flight. Incidentally, perhaps, he would learn to ride all over -creation without motive power; for he was convinced that certain great -birds soar without muscular effort, and that man could acquire this -delightful art in favorable weather. To strengthen the plausibility -of that doctrine, he announced his discovery that the general trend -of the wind is three and a half degrees upward, a fact inexplicable -and almost incredible to his illustrious confrère of the Smithsonian -Institution.[26] Such was Lilienthal’s ample program; more, indeed, -than he would live to accomplish, though possibly not beyond his power -of achievement, if he could have lived to enjoy the hale long years of -his illustrious countryman aëronaut, Count Von Zeppelin. - -In the year 1891 Lilienthal made his first series of trials in sailing -flight. His glider was the bird-shaped apparatus shown in Plate XVI, -made of willow wood covered with waxed sheeting. It weighed about 40 -pounds, and spread 107 square feet of surface. Taking this in his arms -he first ran 24 feet along a raised board and jumped off, gliding -through still air. Then, elevating the board to a height of six feet, -he repeated the run, jump and glide, always landing very softly. Thus -he became “king of the air in calm weather,” a title still creditably -sustained by his numerous successors of the present day; for as yet no -one “mounts the whirlwind and directs the storm.” - -Next he went to some little mounds in a field beyond Werder, and jumped -from these, gradually lengthening his flights till he attained a range -of nearly 80 feet. As he was now gliding in light winds, he found it -necessary to add a vertical rudder, in order to preserve his balance -easily, and keep his bow toward the direction of the wind. His complete -apparatus was, therefore, a birdlike affair, with two rigid wings and -a double tail for steering vertically and horizontally. He found also -that he could fly longer and alight more softly when the wind was -blowing—an obvious possibility. - -Encouraged by this experience Lilienthal explored the country about -Berlin for sailing ground where he could make long glides, whatever -the direction of the wind. Such a region he found near Rathenow, where -the Rhinow hills, covered with grass and heather, slope gently upward -from the flat plowland to a height of over 200 feet. This he thought -an ideal coasting ground; for he felt the aërial currents very smooth, -and he could always select clear land sloping ten to twenty degrees -toward the wind. Here in the summer of 1893, with a new and improved -glider, he made many flights, finally ranging from 200 to 300 yards, -steering up and down, or to right and left at will; sometimes pausing -in mid air, and several times returning to the starting point. This was -more than coasting; for a mere coaster never maintains, nor returns -to, his original level. It was a fair start at true soaring, the ideal -locomotion. A glorious sport it was, sailing like an eagle high over -the landscape and over the heads of the astonished spectators. - -The new machine resembled its predecessors in form and maneuver; but -differed in dimensions. It was a birdlike craft with parabolically -arched wings and a double tail. It measured 7 meters across, spread -14 square meters of surface, weighed with the rider 200 pounds, and -in calm air could sail down a slope of 9°, at a speed of 9 meters -per second. This was very efficient sailing, the work of gravity -being hardly two horse power. With the man lying prone, as eventually -planned, the economy would be still greater. - -PLATE XVI. - -[Illustration: LILIENTHAL’S MONOPLANE GLIDER. - -(Courtesy W. J. Hammer.)] - -[Illustration: LILIENTHAL’S BIPLANE GLIDER. - -(Courtesy W. J. Hammer.)] - -[Illustration: PILCHER’S MONOPLANE GLIDER.] - -The craft was thought also to possess stability; and this it had, in a -measure, about those two axes corresponding to the two rudders; but the -control about the third axis, effected by dangling the legs to right -or left, was extremely crude and primitive. It was in keeping with his -adage: “to contrive is nothing; to construct is something; to operate -is everything.” If he had contrived more intelligently, he would have -operated more easily, and avoided those wild and dangerous dancings in -space. A more scientific adage would read: “To design effectually is -everything, to construct is routine, to operate is play.” - -The marvel is that Lilienthal, the observant, the technically trained, -the practically skilled, should operate for three years, then patent, -an aërial glider having two rudders, but lacking the third rudder, -or torsional wing, now so commonly used throughout the world. But -doubtless he contemplated a device for preserving the lateral balance -without shifting his weight; for he acknowledged the economic advantage -of lying prone on the machine, and stated that this might be done after -some important improvements in the apparatus had been made. - -Having executed nearly two thousand flights with his monoplane, -Lilienthal in 1895 built a two-surface glider. He found this still -easier to control, and now thought he had sufficiently acquired the -art of sailing to justify his undertaking the next and more difficult -art of imitating the rowing flight of birds. He had constructed a -ninety-pound engine, of two and a half horse power, to actuate the -wings of his glider; but, before applying this motor, he went to the -Rhinow Hills for a little further experience in sailing. Previously -he had remained in the air twelve to fifteen seconds; but he wished to -exceed this record. - -On the 9th of August, 1896, he made a long glide to prove the -effectiveness of the horizontal rudder, and then wished to undertake -a second flight of the greatest duration feasible. No intimation had -he that this sail would prove disastrous. Giving the timepiece to his -assistant, he set forth on a level course, but suddenly dipped forward -and plunged headlong to earth through a height of fifty feet. He was -dragged out from the débris with a broken spine, from which he died the -following day. - -The machine on which the father of aërial gliding made his last flight -is shown in Plate XVI. Of the hazardous nature of its construction Mr. -Chanute thus writes: “The two surfaces were kept apart by two struts, -or vertical posts, with a few guy wires, but the connecting joints were -weak, and there was nothing like trussing. This eventually cost his -most useful life. Two weeks before that distressing loss to science, -Herr Wilhelm Kress, the distinguished and veteran aviator of Vienna, -witnessed a number of glides by Lilienthal with his double-decked -apparatus. He noticed that it was much wracked and wabbly, and wrote to -me after the accident: ‘The connection of the wings and the steering -arrangement were very bad and unreliable. I warned Herr Lilienthal very -seriously. He promised me that he would soon put it in order, but I -fear that he did not attend to it immediately.’” - -It will be observed that Lilienthal gave fair attention to the merits -of both the monoplane and the biplane, the two familiar types in -lively competition at the present hour. The first he found in Nature; -the second he could have found in England, as the developments -principally of Wenham and of Phillips. His example and prestige did -much to promote the biplane; but he seems to have had no very decided -preference for either. Though he found his biplane very satisfactory, -he thought of returning to the monoplane. - -In April, 1896, he wrote:[27] “I am now engaged in constructing an -apparatus in which the position of the wings can be changed during -flight in such a way that the balancing is not effected by changing -the position of the center of gravity of the body. In my opinion this -means considerable progress, as it will increase the safety. This will -probably cause me to give up again the double sailing surfaces, as it -will do away with the necessity which led me to adopt them.” He thus -seems to have studied the two types impartially, and to have invented a -means for balancing the machine without shifting the center of mass. - -Lilienthal had given a powerful and permanent impulse to aviation, -both by his writings and by his practical experience in the air. He -first showed quantitatively the advantage of arched wings, by carefully -derived tables of wind pressure; then he mounted the wings himself -and taught the world, by bold and frequent flight, the art of aërial -gravity sailing. The two remaining achievements, dynamic and soaring -flight, he was to undertake as promptly as possible. If his life had -been spared, no doubt he would have contributed much to the advancement -of these arts, both by example and by direct effort; for he was in the -prime of life, full of energy and daring, highly equipped, and ardently -devoted to his favorite science. He began his studies in aviation at -the age of thirteen and died at the age of forty-eight years. - -Among the admirable traits of the father of sailing flight must be -mentioned his scientific liberality and _esprit de corps_. Though he -patented his invention he did not conceal, or withhold, his discoveries -when he could publish them properly. These discoveries were made at -a great sacrifice of time and means, and must have appeared to him -valuable trade secrets; yet he published all his scientific data, his -theories, and observations; he encouraged his confrères in various -countries to witness and emulate his experiments, to share intimately -his laboriously developed knowledge of aviation, to join hands with -him in hastening the advent of practical flight. Such is the _esprit -de corps_ which has ever prevailed among truly scientific men, as -distinguished from the mercenary and commercial; such are the unselfish -investigators whom the world delights to honor, both for their genius -and for their liberal contributions to the common and permanent -possessions of humanity. - -Before his death Lilienthal had the pleasure of knowing that competent -disciples were emulating him in doctrine and practice. One of the -earliest and cleverest of these was Percy S. Pilcher, Assistant -Lecturer in Naval Architecture and Marine Engineering at the University -of Glasgow. In the summer of 1895 he built the glider shown in Plate -XVI. This, like Lilienthal’s, was a double-tailed monoplane arched fore -and aft; but, better than his for manual control, it was straight from -tip to tip, like the designs of Henson, Penaud, and other predecessors. -This improvement was introduced to prevent side gusts from rocking the -craft so readily as they do the V-shaped gliders. His best sailer, the -_Hawk_, shown in the figure, had wings curved one in twenty, about one -third from their front edge.[28] Sometimes he sailed downhill; again -he was towed or launched, like a kite, by means of a cord, running -through five-fold multiplying gear, and drawn by running boys, or a -horse. In both cases he controlled the machine to his own satisfaction, -making in 1897 smooth downhill glides of 700 feet length, from an -elevation of 70 feet.[29] He had also visited Lilienthal, but only -after achieving success at home. - -Having acquired some skill in sailing, Mr. Pilcher began work on a -power machine. This was to be propelled by a screw actuated by an -oil engine, and was to be mounted on wheels backed by stiff springs. -Having observed his speed of descent in gliding, he computed that -two tow-line horse power would float him and his machine, weighing -together 220 pounds. A like result was obtained when he was flown as -a kite. He was, therefore, on the straight road to achieving human -flight on a screw-propelled, wheel-mounted monoplane. If he had been -more cautious he might have been the first person to achieve human -flight in a practicable type of dynamic machine; for he seems to have -equaled, if not excelled, his German master in aëroplane design. But -like the master he provided inadequately for the structural strength -of his glider, and braved too far the dangers of gusty weather. One -stormy day, September 30, 1899, wishing to please several persons who -had come a long distance to see him, he made two trial flights in a -gentleman’s park near Rugby. The second of these proved fatal. The -spectators heard a cracking noise, saw the tail break, and the whole -craft plunge headlong to the ground. Poor Pilcher was mortally hurt and -died thirty-four hours later, without ever regaining consciousness. He -was then in his thirty-third year. - -Had this talented young Briton and his German tutor both lived, there -would doubtless have been a pleasant race and rivalry between them; -for the pupil was forming opinions and plans sufficiently divergent -from those of his master and friend. He did not approve Lilienthal’s -high wings and low center of gravity, nor his V-shape for lateral -equilibrium, nor his flapping wing tips for propulsion, nor his method -of launching the dynamic machine. Fortunately both published their -ideas and experiments, leaving to their successors the task of judging -the merits of their designs, and of adding any improvements that might -still be required in order to achieve final success. - -Contemporary with Pilcher, Mr. Octave Chanute and Mr. A. M. Herring, -in America, were emulating the work of Lilienthal. Mr. Chanute was an -experienced civil engineer, who had previously written a history of -aviation, and experimented with numerous flying models; Mr. Herring, -his employee for the time, was a mechanical engineer who had assisted -in Langley’s experiments, and previously had flown a Lilienthal glider, -and had made researches in the science of mechanical flight. On June -22, 1896, accompanied by two assistants, they went into camp among the -sand dunes, on the southern shore of Lake Michigan, to study the art of -navigating an aëroplane without artificial motive power. Mr. Chanute -thought that the maintenance of equilibrium under all circumstances -was at that time the most important problem of aviation; and that -until automatic stability was secured, it would be premature and -dangerous to apply a motor. He wished to evade, for he did not relish, -Lilienthal’s way of balancing by shifting the body and kicking wildly -at the stars. His main purpose, therefore, was to acquire the pilot’s -science; but secondarily he would learn much about the architecture -of gliders, the behavior of air currents, the elements of propulsion -and sustentation. - -PLATE XVII. - -[Illustration: CHANUTE’S FIVE DECK GLIDER.] - -[Illustration: HERRING IN CHANUTE BIPLANE.] - -[Illustration: HERRING’S COMPRESSED-AIR BIPLANE. - -(Courtesy Carl Dientsbach.)] - -They made some flights with a Lilienthal monoplane; but, finding this -unsafe and treacherous, they discarded it in favor of a multiple-wing -glider designed by Chanute, which after many empirical modifications -in the placement of the sustaining surfaces, assumed the form shown in -Plate XVII. This glider resembled the Lilienthal biplane in having the -surfaces vertically superposed, the rider below them, and the rudder in -the rear; but it was a five-decker whose wings, on either side, could -swerve fore and aft, so as to bring the center of lift always over the -center of gravity, in order to prevent excessive rearing or plunging. -This glider was found very tractable in a twenty-mile wind, and in a -thirteen-mile breeze would sail down a slope of one in four. - -After further study, the five-decker was replaced by a three-decker; -which presently was deprived of its obtrusive and unessential lower -surface, thus assuming the familiar form shown in Plate XVII. As will -be observed, this was a radically new and elegant design, consisting -of two superposed arched surfaces held together by vertical posts and -diagonal wires, like a Pratt truss. It was, in fact, the renowned -“Chanute glider” which has been copied by so many succeeding designers -of biplanes. - -The Chanute glider weighed 23 pounds, spread 135 square feet, and -readily carried a total weight of 178 pounds at 23 miles an hour. It -was provided, as shown, with side planes and a double rudder, and -this latter was elastically connected to the main body to insure -steadiness of flight, on the principle of the elastic wing margins used -by D. S. Brown in 1874. This craft was found easy to manipulate in -launching, sailing and landing, a two-inch shift of the pilot’s weight -equivalencing a five-inch shift on the Lilienthal monoplane. It was -steady at a speed of twenty to forty miles an hour through the air, -even when the wind was blowing seventeen miles an hour overground. The -angle of descent was 7.5° to 11°, depending on the speed and trend of -the wind. The work of gravity expended in maintaining steady flight was -at the rate of two horse power for the 178 pounds, a good showing with -the rider vertical. - -Summer passed before Mr. Chanute could perfect the invention for -automatic stability by means of swerving wings; but otherwise the -gliding experiments were very satisfactory. The strong and simple -biplane evolved during those few weeks of fruitful study, though not -an original creation, having been foreshadowed theoretically and -experimentally, in the work of Wenham,[30] Stringfellow, Lilienthal, -Phillips, and Hargrave, was nevertheless an important contribution to -the science of aviation, by reason of its strength and simplicity of -design, its efficiency, its stability, and, best of all for that day, -its record for good flights and safety. All who could appreciate it -understood that the addition of a light motor would transform it to -a dynamic flyer, navigable at least in mild weather. The most eager, -perhaps, was Mr. Herring; for he had not only mastered this glider, -but some years previously had flown successfully rubber-driven models -very much resembling it in design. These two aviators, therefore, came -to a parting of the ways, Chanute still pursuing automatic stability, -Herring impatiently heading for dynamic flight by the shortest route -available. Had they continued together on a practical course, they -might, ere the close of the century, have anticipated at least the -early flights of the French aviators, if they could have constructed or -purchased an adequate motor. - -After some further development of the aërial glider to adapt it -to power flight, Mr. Herring began the construction of a dynamic -aëroplane. He had previously built very light steam and gasoline -engines,[31] and deemed the latter best for a perfected flyer, though -preferring steam or compressed air in a first experimental test. - -When seen by the present writer in October, 1898, at St. Joseph, -Mich., Mr. Herring was about to launch himself in the compressed-air -driven biplane shown in Plate XVII. It was essentially a powered -Chanute-Herring glider, steadied by a double tail, and controlled by -shift of the pilot’s weight, the tail being elastically attached. -The writer then suggested that both a glider and a dynamic aëroplane -should be controlled entirely by steering and balancing surfaces, on -the principle set forth in his paper of 1893; and, in particular, -indicated that the lateral balance should be controlled by changing the -inclination of the wings on either side, while the double tail should -be used to steer and steady the aëroplane sidewise and vertically; in -other words, that a torque about each of the three rectangular axes of -the machine should be secured from impactual pressure, thus obviating -the need for shifting the pilot’s weight. Mr. Herring, while making no -objection to this proposal, intimated that he had a device for insuring -control without shifting the pilot’s weight, but believed the most -important effort for the moment should be to make a short flight with -the machine as it stood, for the purpose of enlisting capital, then -to add the controlling devices at leisure. He expected to remove the -wheels shown in the figure, hold the aëroplane against a stiff breeze -from Lake Michigan, start the propellers, strike a soaring attitude, -and fly forward for a few seconds against the wind. - -The successful accomplishment of such a flight covering an overland -distance of seventy-three feet in eight or ten seconds, against a wind -of thirty miles an hour, was reported in the Chicago _Evening News_, -of November 17th of that year; but the present writer has not been -able to ascertain the reporter’s name, or that of any other witness to -the event, which, if true, is well worthy of verification and detailed -record. - -In following the votaries of passive flight, as represented by -Lilienthal and his school, we have overlooked the great man-carrying -bird of Clément Ader, one of the most prominent and successful aviators -of that active period. If the reports be true, Ader may justly claim to -be the first person to navigate the air in a dynamic flying machine. -However, it must be observed that his achievements did not at first -arouse in France a great pitch of exultation and enthusiasm. There -seemed at the time to be some skepticism as to the practicability of -his device. But later cordial reparation was made by placing it on the -Stand of Honor at the Aëronautical Salon, held in the Grand Palais, at -Paris, in December, 1908. - -Clément Ader set out in life with the fixed determination to make -a fortune, then to build a practical flying machine. Adopting the -profession of electrical engineer, he quickly accumulated enough -capital, as he thought, to realize his early ambition. He next visited -Africa to study at close range the great soaring birds that Mouillard -had described with so much admiration and vivacity. Going to Algeria -he disguised himself as an Arab, and, with two Arab guides, journeyed -to the interior where he watched the great soaring vultures, which -he enticed with bits of meat to perform before him their marvelous -maneuvers, wheeling in wide circles, and without wing beat, from earth -to sky. - -After several years of study of the anatomy and flight of birds, Ader -began, at the age of forty-two years, to construct an aëroplane. His -first machine was a birdlike monoplane mounted on skids, or wheels, -and driven by a 40-horse-power steam engine actuating a screw, placed -forward. The total weight was 1,100 pounds, the spread 46 feet, the -length 21 feet. The _Eole_, as he called it, received its first -open-air test on the morning of October 9, 1890, in the grounds -surrounding the Chateau d’Armainvilliers, near Gretz, a portion of the -course being so prepared that the trace of the wheels would be visible. -When everything was ready for the trial, Ader mounted the machine, in -presence of a few friends, ran quickly over the ground, urged by the -propeller thrust, then rose into the air and sailed 150 feet. Such is -the report of the witnesses to what is claimed as the first flight of a -human being in a power-driven flying machine. - -Subsequently this bold inventor built _Eole No. 2_, which, by special -permission of the War Department, he tested on a prepared track, 2,400 -feet long, on the Satory Camp. Over this course he ran his machine -several times, and on one occasion flew 300 feet; but on alighting -broke one of the wings. - -Ader, now having spent one and a half million francs on his -experiments, placed the _Eole_ on exhibition in order to raise money -for their continuation. In this venture also he was successful, -being presently subventioned by the French War Department to build an -aëroplane for its use. His subsequent labors are concisely set forth in -_Automobilia and Flight_ for February, 1909, as follows: - - “Under these new conditions the workshop in the Rue Pajou was - abandoned for larger premises in the Rue Jasmin, where the - construction of the _Avion_ was commenced in May, 1892, all - persons engaged with the construction being under a military - vow of secrecy. The motor was built first, and tested before a - commission composed of army officers and some of the leading - technicians of France. It was found to develop 30 horse power - for a total weight of 32 kilogrammes; and even now, though - seventeen years old, is regarded as a _chef d’œuvre_. In the - spring of 1897 the _Avion_ was ready to make flights. Like its - predecessors it was modeled on the form of a bat; but, although - the wings could not be flapped, they could be folded, and - could be advanced or retarded horizontally. - - “Everything appearing satisfactory, Ader informed the military - commission that he was ready to undergo tests; the committee - met at the workshops in the Rue Jasmin on August 18, 1897; - were pleased with the machine, and ordered flights to be made - immediately at Satory. It was not, however, until October 12th - that a flight was attempted on the carefully guarded military - ground, and in the presence of General Mesnier. The apparatus - covered a distance of 1,600 yards, and although it did not fly, - for this distance it is certain that on several occasions it - completely left the ground. Ader declared that according to - whether the wings were carried forward or to the rear, it was - the front or the rear wheels only which left the ground. The - pressure in the generator at this moment varied between 3 and 4 - atmospheres. On increasing it to 6 or 7 atmospheres none of the - wheels touched. - - “Satisfied with the results of the test, General Mesnier called - the commission together for further trials on the following - day, October 14, 1897. Unfortunately it was a rough, squally - morning, that would have prevented many a modern aviator from - bringing a machine into the open. But as the officers had been - brought together specially for this purpose, a flight was - attempted. - - “‘After several revolutions of the propellers, and a few yards - covered at a moderate speed, we were off at a high rate of - travel,’ wrote Ader, who was at the wheel on this memorable - occasion. ‘The pressure was about 7 atmospheres. Almost - immediately the vibrations of the rear wheel ceased, and, - directly after, those of the front wheels were no longer felt, - showing that we had entirely left the ground. Unfortunately - the wind had increased in strength, and I had some difficulty - in keeping to the line that had been marked out. I increased - the pressure to 9 atmospheres, and immediately the speed - increased considerably, the vibrations ceased again, showing - that we had once more left the ground. Under the influence of - the wind the aëroplane had a constant tendency to drift to - the right, away from the circular track that had been marked - for it. Finally, with the wind broadside on, the machine was - in a rather dangerous position, for it was being still more - rapidly driven out of its course. I increased the pressure - still more and put the rudder hard over to the left, with the - result that for a few seconds the machine worked back towards - the track and still maintained itself in the air. But it was - impossible to struggle against the wind, and finding that the - machine was being carried towards some artillery sheds, and - somewhat unnerved by the speed at which the ground appeared to - be rushing past, I stopped the engine; there was a shock, and I - was on the ground.’ - - “Ader was uninjured, but his machine was rather badly smashed. - It had certainly flown, but with such difficulty in the face of - the wind that the army commission was evidently little inclined - to report favorably upon it. Several weeks passed without any - communication being received from the War Department; then it - became apparent to Ader that the Government had no longer faith - in his invention. This was proved early in the following year - by an official communication to the effect that no further - funds could be allotted to this work. Discouraged at the - abandonment after forty years’ labor and the expenditure of - about two million francs, Ader commenced the destruction of his - machines. The earlier ones were destroyed, but the _Avion_, the - one which had appeared before the army commission, was saved - and sent to the Museum of the Arts et Métiers in Paris.” - -The last aëroplane, or _Avion_, weighed 1,100 pounds, spread 270 square -feet, and was driven by a 40-horse-power steam engine actuating twin -screws projecting before the bird-shaped flyer. The engine weighed but -7 pounds per horse power—quite a remarkable achievement for that day. - -In following the votaries of passive flight, as represented by -Lilienthal and his school, we have overlooked the great dynamic -aëroplane of Mr. Maxim, one of the most prominent aëroplane builders of -that active period. Having in 1889 made elaborate experiments on the -atmospheric resistance of sustaining surfaces, and on the thrust of -screw propellers, he proceeded to build the gigantic aëroplane shown -in Plate XVIII, the greatest flyer thus far known to history. It was a -twin-screw multiplane mounted on a platform forty feet long by eight -feet wide, and having four wheels running along a track eight feet -wide and half a mile long. Above the rails of this track were guard -rails to prevent the flyer from rising more than three inches during -the tests. The whole machine weighed 3.5 tons, spread 5,500 square -feet of surface, and, at a speed of 40 miles an hour, lifted more than -a ton, in addition to the weight of the three men and 600 pounds of -water. Its propelling plant comprised a naphtha tubular boiler, and a -compound steam engine of 350 horse power actuating twin screws 17 feet -10 inches in diameter which gave a thrust approximating 2,000 pounds. -These screws were made of American yellow pine, covered with canvas and -painted, then smoothly sandpapered to reduce the friction; for Maxim, -like certain French aviators, erroneously imagined that a polished -surface has less air friction than a dead even surface. The framework -was composed of seamless steel tubing stayed with steel wire. The -aëroplane was to be steered right and left by a rudder, and up and down -by horizontal planes, one fore, another aft, and its lateral stability -was to be secured by side planes set at a dihedral angle. A meritorious -feature for that day were the superposed arched surfaces whose framing -was smoothly covered below and above by skillfully stretched fabric, -causing the air to flow evenly without wasteful eddies. - -PLATE XVIII. - -[Illustration: MAXIM’S AËROPLANE. - -(Courtesy W. J. Hammer.)] - -[Illustration: LANGLEY’S LARGE AËROPLANE. - -(Courtesy Smithsonian Institution.)] - -Many runs along the track were made to test the working of this -great apparatus before trusting it to launch forth in free flight. -Dynamometers gave independently the thrust of the screws, and the lift -of the wings on the front and rear axles. The ascensional planes for -controlling the fore and aft equilibrium were tested during the run, -as also the practical operation of the propelling plant. During the -trials of 1893 the machine frequently lifted clear of the lower track, -and flew forward resting against the guard rails above the wheels. -Finally, on a gusty day, the lift against the upper track caused this -to give way, whereupon the machine rose into the air with Mr. Maxim -and his assistant, then toppled over on the soft earth, suffering -some damage to its framework. Here the experiments were discontinued -for lack of funds, having indeed demonstrated that a large weight -can be carried in dynamic flight, but having proved little as to the -feasibility of controlling an aëroplane in launching, in free flight, -and in landing. - -Compared with the work of his contemporaries this achievement of Mr. -Maxim was herculean, both in construction and expenditure, the cost -being reported as nearly one hundred thousand dollars. It raised high -hopes for aviation. It proved conclusively not only that a flying -machine could be made to lift a pilot, but that it could carry hundreds -of pounds additional weight. It still holds the world’s record for -magnitude of machine and cargo. But it had two great defects; it was -improperly balanced and it was inadequately powered; for, as Mr. Maxim -says, “the quantity of water consumed was so large that the machine -could not have remained in the air but a few minutes, even if I had had -room to maneuver and learned the knack of balancing in the air.”[32] -These defects, however, would soon be remedied by the work of others, -and particularly by the costly experiments of the automobilists, who -were rapidly developing a light gasoline motor suitable for aviation. - -The inventors thus far noticed had developed most of the important -features of the present-day flying machines, but had not provided -adequate mechanism for preserving a steady lateral balance. The present -writer had proposed the combination of a double rudder and torsional -wings to steer and control a flyer, and had published a paper setting -forth its general principle and describing a specific device; but -inventors had little need for a third rudder till they encountered -the dangers of dynamic flight in gusty weather. The paper referred -to was presented to the Third International Conference on Aërial -Navigation, in August, 1893, under the title, _Stability of Aëroplanes -and Flying Machines_, and was published with the proceedings of the -conference.[33] It discusses mainly the question of automatic stability -and steadiness; but recommends personal control during the experimental -period. It concludes as follows: - - “We have been considering the question of automatic stability, - in so far as it may be secured in the construction of the - craft itself,[34] apart from a pilot, or special equilibrating - devices. The application of the latter would give exercise - to an infinite amount of ingenuity, and would, perhaps, best - be left to the fancy of the individual inventor. One curious - design, however, occurs to me, which, since I have not seen it - described elsewhere, may be worth a moment’s notice. - - “Suppose a Phillips’s machine (see Plate XIV) to be provided - with a double tail, and to have a vertical fin extending - longitudinally along its entire length, well above the - center of gravity. These would steady its flight and promote - stability. _Suppose also that its sustaining slats were - pivoted, so that a pilot could at pleasure change their - inclination on the right and left side independently. He could - then set the engine for a desired speed, sweep forward along - the earth with the sustainer slats horizontal, and at will - mount into the air, by giving the slats an upward inclination. - Once in the air he could raise or lower the machine by slightly - changing the angle of the slats; he could wheel to right or - left by giving one set of slats a little different slope from - the other; he could arrest all pitching, rocking and wheeling - by a slight counter movement of the sustainers._ It would be - necessary, of course, to preserve a rapid forward motion, for - it is a peculiarity of the compound aëroplane that, if it comes - to a standstill in the air, it will drop plumb down with a - frightful plunge until it acquires headway.” - -The succeeding paragraph disclosed a specific contrivance embodying -the principle just given. This showed two levers rotating drum shafts -for actuating wires adapted to change the impact angles of the wing -surfaces. Accordingly this much of the mechanism of control, together -with the broad device of the torsion wings, has been the common -property of inventors since the publication of that paper. Furthermore, -the combination of torsional wings and a double rudder, either fixed or -movable, has been public property since that date.[35] - -Little was said about the manner of manipulating the double rudder and -torsional wings; for the rules of manipulation would vary in different -machines, depending upon structural design and external conditions. -For example, if the proposed fin and vertical rudder were ample and -suitably placed, the lateral balance could be controlled by merely -twisting the wings, without touching the vertical rudder; but if the -fin and rudder were not adequate, the lateral poise would be controlled -by twisting the wings and working the vertical rudder conjunctively. -A novice might prefer leaving the rudders fixed and controlling the -poise in short flights by twisting the wings by means of a single lever -having two independent movements, one to rotate the wings oppositely, -the other to rotate them identically. - -The principle of control expressed in italics had been set forth also -in a preceding paragraph. Having proposed means for securing both -stability and steadiness about each of the three axes of an aëroplane, -the text continued: - - “These ends could probably be attained very well by mounting - two compound aëroplanes on a long backbone,[36] somewhat after - the manner of the Hargrave cellular kites, and adding a - compound rudder to the whole.” ... “_If the inclination of the - sustainers, front and back, could be altered independently, - it might be feasible for a pilot to preserve the equilibrium - of the machine even when its center of gravity was frequently - shifted, as by the moving of passengers to and fro._”[37] - -At that date, 1893, an inventor doubtless could have secured a broad -claim on a mechanism embodying the torsion-wing-and-double-rudder -mechanism of control. But in those days aviation was pursued largely -as a liberal study by scientific men who wished to hasten the advent -of practical flight, by presenting important physical measurements -and principles which could be freely employed by all. Accordingly the -three-rudder system of control seems not to have been claimed by an -inventor much before the close of the nineteenth century. Since then it -has been patented in one form or other by many practical aviators, some -endeavoring to claim the whole broad contrivance, others claiming more -restricted devices. - -The static principle of the torsion wing is a familiar one in -elementary mechanics. It is this: a torque of given magnitude and -direction has the same effect on a rigid body whatever its point of -application. The longitudinal torque, or moment, may therefore be -exerted by the wings, by suitable rudders, by forward planes, by any -auxiliary planes, or fins, however placed or moved for the purpose. -Accordingly there seems to be an unlimited variety of concrete -patentable devices available to the inventor for securing impactual -torque about the longitudinal axis, or either of the other two axes. -But in planning such devices it is well to remember that the moment of -a couple increases with its arm, so that in a wide aëroplane the wing -tips may best furnish the torque; while in a high short-winged machine, -vertical planes, fins, or rudders may give the desired longitudinal -moment. Obviously such vertical guiding or controlling surfaces may be -so placed as to tilt the machine toward the center of curvature of its -path, at the same time opposing the centrifugal force, and exerting a -torque about the vertical axis tending to steer the flyer along its -path.[38] - -The principle of projectile stability is another consideration of -some importance in aviation, or more generally in all submerged -navigation, whether of air or water. A submerged body has projectile -stability if its nose tends always to forerun its centroid, and follow -a steady course. A dart is a good example; a fish, a torpedo. Thus if -a torpedo-shaped homogeneous solid be hurled in any manner through a -fluid, obliquely or even tail foremost, it promptly turns its nose to -the front and proceeds steadily along an even course; but if the body -has not true dynamical balance, it may oscillate or gyrate, or flit -about in the most erratic manner. - -Projectile stability in a flyer, as in an arrow, may be attained by -playing the centroid in or near the line of forward resistance, and -well ahead of the side resistance. The reasons for this are manifest. -If, however, this arrangement be neglected, a special damping, or -controlling, device is required to preserve headlong and steady motion. -In particular, the objections to placing the centroid too low were -emphasized in the above quoted paper as follows: - - “I have mentioned the advantage of placing the center of mass - below the center of surface; this has also its objections. - While the stability against inversion is increased, the - stability against rocking is sacrificed. The aëroplane so - constructed may not easily overturn; but it will sway to - and fro with a pendular motion. This, when lateral, is very - objectionable, when fore and aft it is fatal to uniform - progress, as we shall see in studying the longitudinal - stability of flying machines. We shall then see that the center - of mass cannot be lowered with impunity.” - -Of the various flyers and models thus far studied, some manifest fairly -good, others very imperfect projectile stability. Many inventors have -been more alert to the gravitational stability and safety of the -parachute than to the kinetic stability and keen, direct flight of the -arrow. Some of the most pretentious machines imitated the thistle down -more nearly than the dart or swallow. But the exigencies of actual -flight would easily rectify such imperfections of design. - -Tractional balance also is a property of some importance in fluid -navigation. This requires that the line of propulsive thrust coincide -with the line of fluid resistance. It is a property, however, that -inventors readily apprehend, and usually provide for. - -In general a flyer is subject to four forces: weight, thrust, air -pressure and inertia. When these balance about any axis the craft has -equilibrium about that axis; when they balance about the three axes -the craft is completely balanced, and preserves its orientation in -flight. Devices for preserving this complete balance have already been -described; as also provision for propulsion and sustentation, launching -and landing safely. - -Thus at the close of the nineteenth century all the essential -principles and contrivances of pioneer flight were worked out, except -one—a suitable motor. This was the real problem of the ages. The rest -was easy by comparison. A light enduring motor, if available to the -old time inventors, would have brought dynamic flight centuries ago. -That only could have baffled Da Vinci, Cayley, Henson, Wenham and the -long line of pioneer aviators. Eventually, of course, steam engines had -come, endowed with ample power; but costly to build and wasteful to -operate. The light automobile engine appeared in the latter nineties; -promptly thereafter followed the dynamic flyer, the snow-winged herald -of the twentieth century. - - - - - CHAPTER IX - - AËROPLANES OF ADEQUATE STABILITY AND POWER - - -The dawn of the twentieth century found several votaries contriving -aëroplanes for one or more passengers. The epoch of models had -virtually closed, bequeathing a rich heritage. The essential elements -of aviation, barring the motor, had been clearly worked out. The age -of practical flight was at hand. No further need to prove feasible -the heavier than air; for that had been done repeatedly. Scientific -design and patient trial, not invention and physical research, were now -the chief demand. Further research would improve the aëroplane, but -not bring it into practical operation. Capital, constructive skill, -judgment in adapting principles and devices already known, energy, -persistence, caution, imperturbability in danger and derision; these -were requisites. Science had led the way, with uplifted torch; let the -craftsmen follow her with kit and apron. The aëroplane was sufficiently -invented; it now wanted, not fastidious novelty, but concrete and -skillful design, careful construction, exercise in the open field. - -Of the group of aëroplanists in the beginning of the nineteenth century -Mr. Hugo Mattullath, of New York, was one of the most original, daring -and resourceful. He had been a successful inventor, manufacturer and -business man, accustomed to large enterprises. In the latter nineties, -deeming the time opportune for practical aviation, he determined to -build a commercial flying machine. He would begin where Maxim had -stopped. A larger and swifter craft appeared to him most desirable. -In his judgment any clever mechanic could make a one-man flyer. “Take -that for granted and waste no time on toys!” Professor Langley’s -“aërodrome,” with every spare ounce filed away, should lift itself, -of course. It might navigate a calm; possibly even a zephyr, if no -one sneezed; but never could it carry passengers on schedule time. He -therefore would jump the little flyers, and build at once a commercial -aëroplane strong enough to defy the storm, powerful enough for regular -traffic on a business scale. That meant a ship for numerous passengers, -equipped to fly fifty miles an hour against the prevailing wind. A -glorious project indeed; an enterprise suited to a gentleman of first -rate ability. - -Mattullath’s aim was aërial transportation, not exhibition at county -fairs and crowded carnivals. Regular interurban routes were projected, -terminating in ample landing floors. Broad-winged aëroplanes, huge -catamarans with shining hulls, sumptuously furnished in gold and -crimson, should convey happy crews, in all seasons, from metropolis to -metropolis. Six great engines and propellers to drive the ship, with -abundant reserve power. Melodious strains of music rising incessantly, -to soften the thunder of motors and the demoniacal howl of the wind. -Then transcontinental voyages, outsailing the nimbus, how lovely to -the anointed of fortune! Jocund savannas nestling by the sea, or in -the bosom of orchid-crested hills, should welcome to earth the silken -sojourners of the north migrating, gay-plumed and potent, to their -winter homes in tropic paradise. All the isles of ocean, all the merry -mountains, earth, sea and air, one shining empire, blissful and secure -as Olympus. Chimborazo, girt with every clime, from torrid base to -snowy peak should glow - - With alabaster domes and silver spires, - And blazing terrace upon terrace high - Uplifted; here serene pavilions bright, - In avenues disposed; their towers begirt - With battlements that on their restless fronts - Bore stars—illumination of all gems! - -Such were his holiday fancies, seldom revealed, even to his associates. -The public had no intimate part in his project. A few trusted -engineers, eminent in their profession, and a few financiers, formed -his advisory board. For two years he worked on the structural elements -of the great sails, propellers, and framing of his ship. But unhappily -when he was preparing to present his final plans to his council of -engineers, before building the large vessel, he was brought suddenly to -the close of his career.[39] - -Mattullath’s proposed air ship consisted of two parallel torpedo-shaped -hulls sustained by superposed plane or slightly arched surfaces, and -propelled by feathering-paddle disk wheels embedded in the planes; -the engines, cargo and passengers to be placed within the hulls.[40] -This arrangement would enhance the comfort of the passengers at high -speeds, eliminate resistance, distribute the load on the framing, -and increase the moment of inertia of the vessel, thereby rendering -it less sensitive to side gusts. To improve the projectile stability -and steadiness, the centroid was placed as high as practicable. Large -steering planes were used fore and aft on both sides of the vessel, -whose inclination could be changed independently, to turn the ship -about its longitudinal or transverse axis. A vertical rear rudder -steered to right or left, in conjunction with the side planes. All the -posts were of double wedge shape; all the planes were canvassed above -and below to shield the framing, after the style of Maxim. The hulls, -the posts, the planes, all parts, were keenly sharpened to economize -power. The ship was to run over its smooth launching field till it -acquired a rising speed of forty to fifty miles an hour, then continue -accelerating up to velocities sufficient for competition with passenger -trains in all weather. - -While one may easily point out certain questionable features in -Mattullath’s project, as for example, its odd propellers, one can not -so easily estimate its true merits. The torsion wing device for lateral -control and steering, which he claimed in his patent application, -abandoned after his death, now constitutes a very important feature of -every flying machine. His planes for fore and aft control, introduced -by Maxim, are also in general use to-day. The principle of load -distribution, which he greatly prized for diminishing stress and adding -stability, has still to be evaluated by practical test in larger craft -than any now in operation. The closed hull, for comfort and economy at -high speed, is at present popular with many designers. - -One tentative assumption of Mattullath’s, made on the authority of -Maxim and Langley, was that the friction of the air is a negligible -part of the entire resistance encountered by the hull, framing and sail -surfaces. Accepting their experimental conclusion, he designed a flyer -so sharp and smooth in all its parts as practically to eliminate the -pressural, or head resistance. With no skin friction, with scant hull -and frame resistance, he could afford[41] to fly at a very slight -angle, thus minimizing the drift, or wing resistance, while at the same -time securing abundant lift by rapidity of flight. He thus arrived, -by cold deduction from the data of those prominent experimentalists, -at an aëroplane swift as the albatross, and wondrously economical of -power. But his financiers were loath to gamble on that assumption. He -therefore, at their suggestion, instigated systematic measurements -of air friction on smooth surfaces, which demonstrated that in a -sharp aëroplane flying at a very slight angle, the skin friction is -nearly equal to all the other resistances combined. These results were -obtained and published[42] some months after his death. They were -unfavorable to his project, and to all projects for attaining high -speed through the air by excessive sharpening of the vehicle. - -The first dynamic aëroplane of adequate stability and power to carry a -man in prolonged flight, was that of Professor Langley. This machine -was nearly a duplicate, on a four-fold scale, of the gasoline model -previously described, which had flown many times with good inherent -equilibrium. There was accordingly every reason to expect that, -weighted and launched like the model, it would fly with the same poise -and swiftness, even if left to govern itself. Having in addition -a living pilot, provided with rudders for steering and balancing, -together with adequate fuel for a long journey, it seemed to promise -still better results than the model. But an unfortunate accident in the -launching so crippled this carefully designed craft that it fell down -helpless, without a chance to exhibit its powers of sustentation and -balance, even for a moment, in normal flight. - -The first trial occurred on September 7, 1903, in the middle of the -Potomac River at Widewater, Va. The aëroplane was placed on the same -catapult, above the boat, that had previously started the models on -their smooth and rapid maneuvers. The pilot took his seat, and started -the 50-horse-power engine which ran the propellers without appreciable -vibration. Tugs and launches were placed along the course where they -might be of service. Photographers, on the water and along shore, were -ready to furnish important pictorial records of the experiment. The -aëroplane was released and sped along the track attaining sufficient -headway for normal flight; but at the end of the rails it was jerked -violently down at the front, and plunged headlong into the river, -sinking beneath the waves. Buoyed up by its floats, it quickly rose to -the surface, with its intrepid pilot uninjured, and with little damage -to the structure. - -As revealed by an examination of the catapult and photographs, the -guy post that strengthened the front pair of wings had caught in the -launching ways, and bent so much that those wings lost all support. The -aëroplane, therefore, had not been set free in the air, but had been -wrenched and jerked downward. Thus the launching proved nothing of the -propulsive or sailing powers of the machine. - -Those who understand the principles of aviation can judge the merit of -Langley’s “aërodrome”[43] from its mechanical description. As shown in -Plate XVIII, it was a tandem monoplane driven by twin screws amidships. -The pilot seated in the little boat could control the poise and course -by several devices; he could shift his weight longitudinally 4.5 feet, -laterally 2.5 feet; he could elevate and depress the rear double -rudder, which when untouched ensured steady longitudinal poise, on the -principle introduced by Penaud; he could steer to right and left by -turning about its vertical axis, the wind-vane rudder shown below and -rearward of the boat. The lines of lift, propeller thrust and forward -resistance passed through the centroid, or near it, thus providing -for projectile and gravitational stability. In this feature Langley’s -“aërodrome” far surpassed those of his immediate predecessors, whose -machines, by reason of their low centroid, possessed the stability of a -pendulum, rather than that of a dart, or swallow. These various devices -combined should give the craft better control in free flight than that -possessed by any of the models, which had flown successfully many times -in moderate weather. - -If the projectile and steering qualities of Langley’s machine surpassed -those of its predecessors, the propelling mechanism was a still -greater advance in the art of aviation. The gasoline engine was a -marvel of lightness, power, endurance and smoothness of running. It -weighed, without accessories, 125 pounds, and developed 52.4 horse -power in actual test at a speed of 930 revolutions a minute. With -all accessories, including radiator, cooling water, pump, tanks, -carburetor, spark coil and batteries, it weighed 200 pounds, or -scarcely five pounds per horse power—a great achievement for that time. -It could run many hours continuously under full load, consuming about -one pound of gasoline per horse power per hour. Its five cylinders, -arranged radially round a single crank shaft, were made of steel lined -with cast iron, and measured 5 inches in diameter by 5.5 inches in -stroke. Its running balance was excellent. By means of bevel gears it -drove the twin screws at 700 revolutions per minute, giving a thrust -of 480 pounds, the screws being very nearly true helices of unit pitch -ratio and 30° width of blade, carefully formed of three radial arms -covered with canvas. - -The whole machine weighed 830 pounds, including the pilot; spread 1,040 -square feet of wing surface; measured 48 feet from tip to tip, and 52 -feet from the point of its bowsprit to the end of its tail; soared at a -speed of about 33 feet a second and a ten-degree angle of flight, the -wings arching one in eighteen at one fourth the distance from their -front edge. The double rudder, at the extreme rear, measured 95 square -feet in each of its component surfaces. - -It is evident from these figures, very kindly furnished by Mr. Manly, -the mechanical engineer in charge of the experiments, that such an -aëroplane had every equipment needed for a steady flight of many hours -in fair weather. A thrust of 490 pounds on well-designed surfaces -should easily carry 500 pounds of gasoline in addition to the 830 -pounds regular weight of ship and pilot. This would enable the machine -to fly practically all day without renewal of supplies. It appears, -therefore, that Professor Langley had, in 1903, a dynamic aëroplane -quite the peer, in many respects, of the best that were developed -during the first decade of aviation, and that a mere accident, which -should be expected in such complex experimentation, deprived him of -the credit of the first man-flight on an adequately controlled and -powered machine. Quite true, he lacked launching wheels; but how easy -to add these, since they were proposed many times. He omitted the -front steering plane, but had a rear one serving the same purpose. The -worst that can be said is that he needed the equivalent of torsion -wings for lateral control; but in moderate weather he could have flown -successfully without them, as Farman, Delagrange, Paulhan[44] have so -fully demonstrated. Besides, Langley had already tested the torsion -wing device, and contemplated using it on his large machine. - -A second launching was attempted on the Potomac River near Washington, -on December 8, 1903. This time the rear guy post was injured, crippling -the rear wings, so that the aëroplane pitched up in front and plunged -over backward into the water. After some repairs it was stowed away -in the Smithsonian Institution, where its frame and engine are still -intact, its wings having been injured in the wreck and discarded. The -experiments were now abandoned for want of funds to continue them. - -Notwithstanding that Professor Langley had contributed much to the -science of aërodynamics, by his elaborate researches, and had really -developed a machine capable of sustained flight, if properly launched, -he was subjected to unmitigated censure and ridicule; for he had -incurred the enmity of various journalists and wiseacres, partly by -his official secrecy, and partly by that natural reticence which -avoids premature publicity in important scientific enterprises. This -irresponsible criticism, combined with the cessation of work which -should have brought success, profoundly grieved him, and doubtless -hastened his death. He had, however, the satisfaction of knowing that -a few competent specialists appreciated his labors, and would continue -them to abundant fruition. A few days before his death he had the -gratification of receiving, from the newly formed Aëro Club of America, -the following communication acknowledging the value of his efforts to -promote aërial travel. - - - RESOLUTIONS OF THE AËRO CLUB OF AMERICA - - _Adopted January 20, 1906._ - -“_Whereas_, our esteemed colleague, Dr. S. P. Langley, Secretary of -the Smithsonian Institution, met with an accident in launching his -aërodrome, thereby missing a decisive test of the capabilities of this -man-carrying machine, built after his models which flew successfully -many times; and whereas, in that difficult experiment, he was entitled -to fair judgment and distinguished consideration because of his -important achievements in investigating the laws of dynamic flight, and -in the construction of successful flying models; therefore be it - -“_Resolved_, That the Aëro Club of America, holding in high estimation -the contributions of Dr. Langley to the science of aërial locomotion, -hereby expresses to him its sincerest appreciation of his labors as a -pioneer in this important and complex science; and - -“_Be it further resolved_, That a copy of these resolutions be sent to -the Board of Regents of the Smithsonian Institution and to Dr. Langley.” - -This kindly message from America’s foremost aëronautic society brought -a moment’s pleasure to the last hours of the illustrious scientist. -“Professor Langley was on his deathbed when these resolutions were -brought to his attention, and when asked what should be done with the -communication, his pathetic answer was: ‘Publish it.’ To all who know -his extreme aversion to publicity in any form, this reply indicates how -keenly he felt the misrepresentation of the press.”[45] - -Professor Langley’s progress with the “aërodrome” was due largely to -the skill, energy and devotion of his designer and superintendent of -construction, Mr. Charles M. Manly. This talented young graduate in -mechanical engineering, of Cornell University, in 1898, went directly -from the class room to assume the chief burden of Langley’s researches -in aërodynamics, and his practical experiments in mechanical flight, -remaining till their termination in 1904. He was the confidential -secretary and adviser to his chief in that whole enterprise. When -in 1900 Dr. Langley stood baffled before the greatest obstacle in -aviation, unable to find any manufacturer, in America or Europe, who -could furnish a practical engine of the desired power, lightness and -durability, Manly came to his rescue with a design which guaranteed -success and which resulted in the wonderful gasoline motor built in the -Smithsonian shops. Finally when the aëroplane was ready to be launched, -it was Manly who bore the long weeks of trial in the malarial region of -Widewater, harassed by accidents and foul weather, not to mention the -merry agents of the press; and it was he who twice rode the ponderous -aërodrome, shot forth in mid air at the imminent risk of his life. - -While Langley was building his great tandem monoplane, Wilbur and -Orville Wright of Dayton, Ohio, were developing a biplane which was -an improvement on the aërial glider of Chanute and Herring. This was -to be their preliminary effort toward achieving continuous flight. -Their first product, tried at Kitty Hawk, North Carolina, in the -summer of 1900, is shown in Plate XIX. The chief points of departure -from Chanute and Herring’s glider were (1) to place the rider prone -on the lower surface, as first proposed and tried by Wenham, forty -years’ previously; (2) to discard the vertical rudder; (3) to place -the horizontal rudder forward, as done by Mattullath and Maxim; (4) -to control the lateral balance by changing the impact angles of the -wings, as recommended by the present writer in 1893. Of these four -modifications the first was impractical for general use, though good -for soaring and possibly racing; the second was unsatisfactory and -later abandoned; the third was effective, and has been accepted by -some aviators as an improvement, but rejected by others who prefer the -rear[46] horizontal rudder; the fourth proved acceptable to them, as to -various other inventors before and after them. - -With this glider they made a number of satisfactory flights. The front -rudder and the torsional wings proved adequate to control the craft -in sailing straight ahead down the Kill Devil sand hills, near Kitty -Hawk, N. C. In this, as in all their machines to the present date, sled -runners, fixed under the machine, as proposed by Ader and others, were -used for launching and landing. With a surface of 165 square feet, they -could glide down a slope of 9.5° at a speed of 25 to 30 miles an hour. -This showed only a moderate efficiency, but it was a beginning. - -The glider used in the summer of 1901 was modeled after that of the -previous year, but larger. It was 22 feet wide, 14 feet long, 6 feet -high, spread 308 square feet, and weighed 108 pounds. With this a -number of glides were made, of various lengths up to 400 feet. At a -speed of 24 miles an hour gravity exerted on the aërial coaster 2½ -tow line horse power, showing an efficiency nearly equal to that of -Pilcher’s glider of 1897. - -In camp with the Wright brothers in 1901 was Mr. Chanute, the leading -aëronautic expert in America. They thus had the advantage of -his long experience, both as a student of aviation and a practical -experimenter. With them were also two other specialists, Mr. E. C. -Huffaker, an experienced aëronautical investigator, who had worked -successively with Langley and Chanute; and Dr. G. A. Spratt, who had -made some important investigations on the value of curved surfaces and -the travel of the center of pressure with the varying angles of flight. -The numerous animated conferences with these gentlemen were instructive -and profitable. When the season closed the brothers returned home and -experimented on curved surfaces to improve the efficiency of their -glider. - -PLATE XIX. - -[Illustration: FIRST WRIGHT GLIDER.] - -[Illustration: SECOND WRIGHT GLIDER.] - -The 1902 machine, shown in Plate XIX, had two main surfaces, measuring -each 32 by 15 feet, and a front rudder measuring 15 square feet. The -whole weight was 116 pounds. It will be noted that a vertical rudder -was now employed. This was a reversion to the design of Chanute and -Herring, but after some experience, the rudder was made adjustable, -as in Henson’s aëroplane of 1842. Its surface was 12 square feet, -but later reduced to six. With this machine they obtained between -700 and 1,000 glides during the season. It showed greater efficiency -than its predecessors, its normal angle of descent being estimated at -seven degrees or less. This was some improvement over the efficiency -of the Chanute-Herring glider, partly due, of course, to placing the -rider flat, instead of allowing him the more comfortable erect posture -adopted later. - -Whatever improvements of efficiency and strength had been made, -these were of secondary importance compared with the provisions for -projectile stability and manual control. Here at last, after ten -years’ groping, was an actual glider with sufficiently high centroid -to minimize the pendulum effect, and with three rudders to give -impactual torque about the three axes. These simple provisions had -been previously pointed out in aëronautic writing, and, in the latter -nineties, had been embodied in Mattullath’s aëroplane, but not tested -in the large machine, owing to his death. The wonder is that, of all -the practical inventors of aëroplanes, Mr. Mattullath was the only -one of that period fully to grasp and adopt these main ideas before -starting to build a man-carrying machine. However, it must be added -that he had previously made small flying models, which may have -suggested the advantage of kinetic stability and the three-torque -system of control. If Lilienthal and his disciples, who laid so much -stress on gliding experience, had started like Mattullath with three -torque-surfaces, they would have missed indeed those acrobatic and -picturesque kickings at the sky, but they would have reached the -desired goal with less danger, time and expense. They displayed more -skill in riding a fractious glider than in designing a tractable -one, by providing for impactual torque about each of three axes. Had -they started with a good theory of dynamic control, they could have -dispensed with coasting entirely, and commenced aviating with short -runs over a smooth course followed by cautious leaps in the air, after -the style of certain ingenious French aviators. However, the knack -of balancing was finally acquired, and thus the glider was ready to -receive the propelling mechanism. - -In 1903 a 16-horse-power engine and twin-screw propellers were applied -to the navigable glider at Kitty Hawk, as shown in Plate XX. The power -machine weighed 750 pounds, and was usually started by aid of a tow -line and falling weight which helped the craft to acquire headway. -After many trials and modifications, the first successful launchings, -four in number, were made on December 17th. The first flight lasted -12 seconds, the next two a little more, the fourth lasted 59 seconds, -covering a distance of 852 feet over the ground in the face of a -twenty-mile wind. To the superficial observer these performances did -not seem a very remarkable advance on the flights of Ader, but they -had in them greater promise and potency of practical flight. They were -the first flutterings of a fledgling endowed with the chief essential -organs of aërial locomotion—an awkward but healthy creature that had -been evolving steadily for several generations. It would grow rapidly, -and ere another half decade, increase the 59 seconds to so many minutes. - -PLATE XX. - -[Illustration: FIRST WRIGHT AËROPLANE (REAR).] - -[Illustration: FIRST WRIGHT AËROPLANE (SIDE).] - -The experiments were continued during the next two years with -increasing success. During the season of 1904, on a field near Dayton, -one hundred and five flights were made, some short, others covering the -entire circuit of the field no fewer than four times, the two largest -measuring each nearly three miles, each accomplished in about five -minutes. Various improvements were made in the propelling and steering -mechanism, and increased skill in maneuvering was gradually acquired. - -In 1905 the flights were resumed with a new machine embodying some -changes dictated by experience, particularly in the method of control. -Forty-nine landings were made involving seven breakages, but no -personal injury. On September 26th a flight of eleven miles was -achieved. This was followed, within the next nine days, by flights of -twelve, fifteen, twenty-one and twenty-four miles, at a usual speed -of 38 miles an hour. After this the field practice ceased for more -than two years, and the machine was dismantled to preserve secret its -mode of construction till the patents could be disposed of. As these -performances and those preceding are of unusual interest, a fuller -account is given in Appendix IV. - -The Wright brothers now had to assume in aviation the rôle of cautious -business men. The gliding experiments had been a scientific recreation, -and had been fairly well reported to engineers, except in those details -to be covered by patent claims; but the details of the power machine -were withheld, or sparingly disclosed. The brothers had sacrificed -time and money. They were making aviation a profession. They must, -therefore, be repaid. But if they exhibited too promptly their machine -and aërodynamic data, they might jeopardize their financial interests -by assisting or stimulating rival aviators. On the other hand, by -procrastination and concealment they might, in various ways, forfeit -priority and scientific credit. Chanute’s glider was already familiar -in Europe, and it was estimated to have ample efficiency for successful -flight with existent motors. Their own published experiments were -being studied and repeated. They might, therefore, expect that, at any -time, some rash or cunning fellow would bolt into the air and proclaim -to all the world that their unpublished devices, if they possessed -any novelty, were by no means necessary, as they fancied, to usher -in actual dynamic flight. The aëroplane would thus appear to be the -sudden outgrowth of fertile and mature conditions, rather than the -product of uncommon originality. Scores of aviators would immediately -spring into being—chauffeurs, mechanics, sporting gentlemen of every -dye. Light motors being now available, any intelligent artisan could -power a Hargrave kite, or Chanute glider, and soar aloft. Every odd -craft, not too absurdly designed, would navigate, with some showing. -Publicity and prize money would develop and perfect the various types -with feverish haste. But in 1905 the Wright brothers apprehended no -portentous or imminent invasion of the sky. The foreign bogie was five -years behind, being unfamiliar with sand hill practice and the torsion -wing. They would, therefore, chance the result of withholding their -data and concealing their machine. It was a curious situation; Langley -and Manly, who produced the first aëroplane endowed with all the -essential powers of prolonged flight, were bound to official secrecy; -the Wrights, who had a finished machine, tried and fairly ready for -public exhibition, were hampered by trade secrecy. These silent leaders -in aviation presented a gratifying contrast to the shouting fraternity -who, in the daily press, announced impending marvels which never -materialized. - -The same year, 1905, which crowned with most success the private -flights of the Wright brothers, brought into unusual prominence -the quarter century long experiments of Prof. J. J. Montgomery of -Santa Clara College, Santa Clara, Cal. He had given much attention -to the science of aviation, particularly to passive flight, and had -constructed several successful gliders operated by himself or his -friends. The most remarkable of these machines was a glider resembling -in general appearance Langley’s tandem monoplane, but having means for -changing the wing curvature during flight, thus varying the lift on -such wing, and thereby enabling the operator to control the equilibrium -and direction during his glides in the air. - -On April 29, 1905, a forty-five pound glider of this pattern bearing an -intrepid parachute jumper, Daniel Maloney, was lifted from the college -grounds by a hot-air balloon to an elevation of 4,000 feet, then cut -loose. “In the course of the descent,” writes one of his pupils, “the -most extraordinary and complex maneuvers were accomplished—spiral and -circling turns being executed with an ease and grace almost beyond -description, level travel accomplished with the wind and against it, -figure-eight evolutions performed without difficulty, and hair-raising -dives were terminated by abrupt checking of the movement by changing -the angles of the wing surfaces. At times the speed, as estimated by -eye-witnesses, was over sixty-eight miles an hour, and yet after a -flight of approximately eight miles in twenty minutes the machine was -brought to rest upon a previously designated spot, three-quarters of -a mile from where the balloon had been released, so lightly that the -aviator was not even jarred, despite the fact that he was compelled -to land on his feet, not on a special alighting gear.” This daring -performance amazed the world, and most of all, the specialists who all -along knew such a feat to be practicable. As a further description -of Professor Montgomery’s wonderful experiments may interest the -reader, the following account, written by himself, is inserted from -_Aëronautics_ for January, 1909: - - “When I commenced practical demonstration in my work with - aëroplanes I had before me three points. First, equilibrium; - second, complete control; and third, long continued or - soaring flight. In starting I constructed and tested three - sets of models, each in advance of the other in regard to the - continuance of their soaring powers, but all equally perfect - as to equilibrium and control. These models were tested by - dropping them from a cable stretched between two mountain - tops, with various loads, adjustments and positions. And it - made no difference whether the models were dropped upside down - or in any other conceivable position, they always found their - equilibrium immediately and glided safely to earth. - - “Then I constructed a large machine patterned after the - first model, and with the assistance of three cowboy friends - personally made a number of flights in the steep mountains near - San Juan (a hundred miles distant). In making these flights I - simply took the aëroplane and made a running jump. These tests - were discontinued after I put my foot in a squirrel hole, in - landing, and hurt my leg. - -PLATE XXI. - -[Illustration: MONTGOMERY’S AËROPLANE.] - - “The following year I commenced the work on a larger scale, by - engaging aëronauts to ride my aëroplane dropped from balloons. - During this work I used five hot-air balloons and one gas - balloon, five or six aëroplanes, three riders—Maloney, Wilkie - and Defolco—and had sixteen applicants on my list and had a - training station to prepare any when I needed them. - - “Exhibitions were given in Santa Cruz, San José, Santa Clara, - Oakland and Sacramento. The flights that were made, instead - of being haphazard affairs, were in the order of safety and - development. In the first flight of an aëronaut the aëroplane - was so arranged that the rider had little liberty of action, - consequently he could make only a limited flight. In some of - the first flights, the aëroplane did little more than settle in - the air. But as the rider gained experience in each successive - flight I changed the adjustments, giving him more liberty of - action, so he could obtain longer flights and more varied - movements in the flights. But in none of the flights did I - have the adjustments so that the riders had full liberty, as - I did not consider that they had the requisite knowledge and - experience necessary for their safety; and hence, none of my - aëroplanes were launched so arranged that the rider could make - adjustments necessary for a full flight. - - “This line of action caused a good deal of trouble with - aëronauts or riders who had unbounded confidence and wanted to - make long flights after the first few trials, but I found it - necessary as they seemed slow in comprehending the important - elements and were too willing to take risks. To give them the - full knowledge in these matters I was formulating plans for a - large starting station on the Mount Hamilton Range from which - I could launch an aëroplane capable of carrying two, one of my - aëronauts and myself, so I could teach him by demonstration. - But the disasters consequent on the great earthquake, - completely stopped all my work on these lines. The flights that - were given were only the first of the series with aëroplanes - patterned after the first model. There were no aëroplanes - constructed according to the two other models, as I had not - given the full demonstration of the workings of the first, - though some remarkable and startling work was done. On one - occasion, Maloney in trying to make a very short turn during - rapid flight pressed very hard on the stirrup which gives a - screw shape to the wings and made a side somersault. The course - of the machine was very much like one turn of a corkscrew. - After this movement, the machine continued on its regular - course. And afterwards Wilkie, not to be outdone by Maloney, - told his friends he would do the same, and in a subsequent - flight, made two side somersaults, one in one direction and - the other in an opposite, then made a deep dive and a long - glide, and when about three hundred feet in the air, brought - the aëroplane to a sudden stop and settled to the earth. After - these antics, I decreased the extent of the possible change in - the form of wing surface so as to allow only straight sailing - or only long curves in turning. - - “During my work I had a few carping critics that I silenced - by this standing offer: If they would deposit a thousand - dollars I would cover it on this proposition. I would fasten a - 150-pound sack of sand in the rider’s seat, make the necessary - adjustments, and send up an aëroplane upside down with a - balloon, the aëroplane to be liberated by a time fuse. If the - aëroplane did not immediately right itself, make a flight, and - come safely to the ground, the money was theirs. - - “Now a word in regard to the fatal accident.[47] The - circumstances are these: The ascension was given to entertain a - military company in which were many of Maloney’s friends, and - he had told them he would give the most sensational flight they - ever heard of. As the balloon was rising with the aëroplane, - a guy rope dropping switched around the right wing and broke - the tower that braced the two rear wings and which also gave - control over the tail. We shouted Maloney that the machine was - broken but he probably did not hear us, as he was at the same - time saying ‘Hurrah for Montgomery’s air ship,’ and as the - break was behind him, he may not have detected it. Now did he - know of the breakage or not, and if he knew of it did he take a - risk so as not to disappoint his friends? At all events, when - the machine started on its flight the rear wings commenced to - flap (thus indicating they were loose), the machine turned on - its back and settled a little faster than a parachute. When - we reached Maloney he was unconscious and lived only thirty - minutes. The only mark of any kind on him was a scratch from a - wire on the side of his neck. The six attending physicians were - puzzled at the cause of his death. This is remarkable for a - vertical descent of over 2,000 feet.” - - - - - CHAPTER X - - ADVENT OF PUBLIC FLYING - - -In 1903, Mr. Ernest Archdeacon stimulated by a conference with Mr. -Chanute, at a meeting of the Aëro Club of France, founded a prize of -3,000 francs to be awarded to the first person who should sail or -fly 25 meters, with a maximum descent not exceeding one third of the -range. As yet no one in either hemisphere had flown in a practical -machine, but various aviators were industriously pluming their wings. -Captain Ferber had been a follower of Lilienthal since 1898, and a -pupil of Mr. Chanute since 1891. Dozens of votaries in France, not -to mention other countries, had entered, or were about to enter, the -aviation field. Archdeacon himself, Voisin, Blériot, Esnault-Pélterie, -Vuia, Delagrange, Tatin, Cornu, Bazin, Levavasseur and many others, -were stanch apostles of the heavier than air. Many of these were -disciples of Lilienthal, but they were destined all to be distanced -by an impetuous Hensonite, who could not realize the necessity for -spending months, or years, cautiously coasting downhill to acquire the -adroitness requisite to speed a flying chariot over the plain. - -In 1906, while many aviators in Europe were developing flyers, and -cautiously testing them in various ways, by gliding above sand or -water, or swinging from a high wire or traveling arm, Señor Alberto -Santos-Dumont, of Brazil, brought forth in France the quaint and crude -biplane shown in Plate XXII. Aërodynamically this was not a great -improvement on the aëroplane of Sir George Cayley constructed 98 years -earlier; but it had a petrol motor whose power and lightness would -have astounded that talented pioneer in aviation. The motor was an -eight-cylinder Antoinette, weighing 170 pounds and developing 50 horse -power. The screw, formed of two aluminum blades, was of two meters -diameter, one meter pitch, mounted on the engine shaft, and, at 1,500 -revolutions a minute, gave a thrust of 330 pounds. The total lifting -surface of the aëroplane was 650 square feet, and the weight, including -pilot, 645 pounds. This bird-shaped craft ran tail foremost through the -air, having the screw at the rear, and the rider in a small basket just -before the wings. By means of a pilot-wheel and lever, he could operate -the “tail,” i. e., the front rudder, sidewise and vertically, thus -steering the craft in two directions. The lateral balance was preserved -automatically by means of the dihedral inclination of the wings, aided -sometimes by the rider swaying his weight to right or left. - -After some days of preliminary adjustment and trial, Santos-Dumont was -ready for a dash in his new aëromobile. On August 22d, 1906, he made -a brief tentative flight, the first witnessed in Europe since Ader’s -surreptitious experiment. On October 23d, he ran this strange machine -swiftly over the ground and glided boldly into the air, flying above -the excited spectators at a speed of 25 miles an hour, and covering -a distance of 200 feet, thus gaining the Archdeacon cup. Again on -November 12th, 1906, he made four flights, the last one covering 220 -meters in twenty-one seconds, thus gaining the prize of 1,500 francs -offered by the Aëro Club of France for the first person who should fly -100 meters. The demonstration was made before the general public and -technical witnesses, including an official committee of the Aëro Club -of France, who reported that the aëroplane preserved good balance and a -true soaring speed independent of the acquired momentum. - -Intrinsically the achievements of November 12th were crude and -primitive; but in moral effect they were very important. They marked -the inception of public aëroplaning before the professional and lay -world alike. There was no patent mechanism to conceal, no secret to -withhold from rivals, such as had shrouded the work of more circumspect -aviators in Europe and America. If Santos-Dumont was not the first to -fly, he was the first aëroplane inventor to give his art to the world, -and to inaugurate true public flying in presence of technical men, as -he had initiated modern motor ballooning. His liberal enthusiasm and -that of his colleagues, both aëroplanists and patrons, quickly made -France the world’s foremost theater of aviation, at least for the -moment. The contagion would of course spread swiftly, and involve the -entire civilized world. - -Santos-Dumont’s unconventional dash into the air sounded the knell of -Lilienthalism. This slow method served to pass time profitably in the -nineties, while the gasoline motor was still developing. But with an -_Antoinette_ in hand, what live man, particularly what live Frenchman, -could tinker long years on the sand hills? Why not mount the craft -on little wheels and take a cautious little run; then after some -adjustment, make more runs followed by innocuous saltatory flights? -This would be so easy, so fascinating, so instructive. How much better -than to make two thousand preliminary jumps down the hill slope -with the body dangling wildly to keep the balance, then to redesign -the entire frame before an engine could be successfully applied! -An _Antoinette_ motor, placed on a competently designed Henson -aëroplane, would have obviated the whole Lilienthal school. However, -they did noble and opportune work, while awaiting the growth of the -gasoline engine. This school achieved success by a roundabout method -because Henson’s method was not available till the present century, -for want of a cheap, light motor. When that appeared Lilienthalism -quickly subsided. In other words, Lilienthal’s method was a passing -convenience, never a necessity. It could have been employed very -profitably in Cayley’s time to develop the art of gliding and soaring; -but in the time of Santos-Dumont and his colleagues, flying by Henson’s -method would have burst upon the world by reason of its superior value -and the allied progress, even if the Lilienthal school had never -existed. This is illustrated by the fact that Santos-Dumont succeeded -without aid from the sand-hill votaries. - -PLATE XXII. - -[Illustration: SANTOS-DUMONT’S BIPLANE. - -_Photo E. Levick, N. Y._] - -[Illustration: SANTOS-DUMONT’S _DEMOISELLE_. - -(Courtesy A. J. Moisant.)] - -The next daring aëroplanist to arouse the world of aviation was Henri -Farman, also a votary of the wheel-mounted flyer. He had been an adept -motorist, therefore accustomed to brisk driving. In the summer of -1907 he received from the Voisin brothers the aëroplane illustrated -in Plate XXIII. With this he made a number of preliminary flights -during the autumn, proving that his aëroplane had suitable stability -and motive power. On October 26th, on the government drill grounds at -Issy-les-Moulineaux he surpassed Santos-Dumont’s record, by flying -771 meters. But this was to him of minor importance; he was preparing -to win the Deutsch-Archdeacon prize of 50,000 francs offered for the -first person who should fly one kilometer over a returning course. -On January 12th, he convoked a committee of the Aëro Club of France -to witness a trial on the morrow. Next morning at ten o’clock, the -weather being calm and clear, his great machine ran a hundred yards -across the course, then rose gracefully into the air, and sailed away -for the 500-meter post. Here, making a wide curve, it rounded safely -and returned, passing the home line in elegant flight, thus winning the -grand prize. - -The machine with which Farman achieved his first success, and which -broadly resembles his subsequent triumphal flyers, seems to be a cross -between a Hargrave kite and a Chanute glider, having a Maxim horizontal -steering plane in front. As shown in the figure it was mounted on -four bicycle wheels; was steered up and down by the front plane, and -sidewise by the box rudder seen in the rear. The rider seated between -the large supporting surfaces, and in front of his engine, operated -these rudders separately, by pushing or rotating a pilot wheel, and -abetted the automatic lateral balance by swaying his body. The machine -spread 559 square feet of sustaining surface, weighed 1,100 pounds -and carried a 50-horse-power _Antoinette_ motor actuating a single -two-blade aluminum propeller 6.9 feet in diameter by 3.6 feet pitch, -directly connected to the engine shaft. The stability in mild weather -was so great that Farman, during his first few weeks’ practice, made -over 200 flights, measuring in length from 100 to 500 yards, without -serious mishap. In gusty weather, however, his machine was defective -in steadiness, and unsafe near the ground. This objection was remedied -later by adding flexible wing margins for controlling the lateral -balance. - -The age of prize flying was thus fairly ushered in by the feeble but -very important public demonstrations of Santos-Dumont and Henri Farman. -Other public flyers would quickly follow. Delagrange, Blériot, Curtiss -would soon become international figures, not to mention numerous more -recent aviators. They, were men of originality, skill and energy, -who would shortly be in the front line contesting for world laurels, -and winning them gloriously. - -PLATE XXIII. - -[Illustration: FARMAN BIPLANE, 1908. - -(Courtesy W. J. Hammer.)] - -[Illustration: FARMAN BIPLANE, 1909.] - -[Illustration: HARMON IN FARMAN BIPLANE.] - -Leon Delagrange, the sculptor-inventor, who first had demonstrated -the biplane, on March 30, 1907, aspired in 1908 to outfly Farman. -He now practiced industriously on the military drill ground at -Issy-les-Moulineaux, a large field which the Minister of War permitted -the Aëro Club of France to use for such purpose. Here he and Farman, -in friendly competition, flew day by day over gradually increasing -courses. At times they were joined by other aviators, and thus the -drill grounds at Issy became famous as an aviation school. - -Farman’s new rival made startling progress during those frequent trials -of March, 1908. “Just imagine,” he says, “that within a week I was -able to complete my education as an aviator.” On March 17th he made an -official flight of 269.6 meters, thus winning a prize of 200 francs -offered by the Aëro Club of France for a beginner who should fly over -200 meters. Four days later he engaged in contest with Farman. Two -poles were erected 500 meters apart to mark the points about which the -men must race. The machines were brought forth from their sheds in -the morning, gleaming dimly through a dense fog, and were given some -preliminary trials. Then Farman made a flight of 2004.8 meters, going -twice around the course in 3 minutes, 31 seconds. He thus trebled his -grand prize flight of January. Presently Delagrange took wing and flew -1,500 meters in 2.5 minutes. Having been beaten by Farman, he invited -his successful rival to take a seat behind him, and the two sailed away -close to the ground, covering a distance of 50 meters. This was the -first trip ever made by two men in one flying machine. For the first -time also two machines had flown in competition over a considerable -course. - -Delagrange continued to pursue Farman for the championship. On April -11th, he flew 2,500 meters, and would have exceeded Farman’s official -record of 2,004 meters, had he not touched the ground. The next day -he summoned the official committee of the Aëro Club of France to -witness and time his performance. Poles were erected at the corners -of a triangle 350, 200, 275 feet apart respectively. Around this -course he flew nearly five times, covering a distance of 5,575 meters -in 9¼ minutes. Of this range the last 3,925 meters were covered -without touching the ground. Thus at last he had out-flown Farman and -established a new official record, the total distance actually covered -being about ten kilometers, or approximately six miles. This ended, -at least temporarily, the friendly competition at Issy; for now the -aviators separated, Farman going to Belgium, Delagrange to Italy. - -Delagrange’s fortune accompanied him abroad. On May 24th, he made some -impressive demonstrations on the Place d’Armes at Rome in presence of -the Minister of War and thirty thousand people. On May 27th, he flew -before the King and Queen of Italy and many other court personages, -remaining in the air nine and one half minutes, thus surpassing all -previous European records for endurance and distance. But this was -only preliminary. On the morning of May 30th, he came forth again on -the Place d’Armes, a light breeze blowing. His machine rolled quickly -over the ground, then circled gracefully ten times around in the air -at a height of four to seven meters, covering an official distance of -12.75 kilometers, and remaining aloft 15 minutes, 26 seconds. On June -22d, at Milan, he flew before 15,000 people in the Place d’Armes, -covering seventeen kilometers in 16 minutes, 30 seconds. Finally, on -September 6th, at Issy-les-Moulineaux, he flew 29 minutes, 54 seconds, -covering 14.8 miles, which proved his crowning effort for the year. As -the two flights just mentioned surpassed all previous official ones -in duration, it appears that Delagrange raised the world’s record -four times within five months, increasing his own time from six and a -half minutes in April to about thirty minutes in September, or nearly -fivefold. - -In the meantime, Farman was making rapid progress, gathering prizes and -achieving wide renown. On May 30th, at Ghent, Belgium, taking with him -M. Archdeacon, he flew 1,241 meters at a height of seven meters. He -thus established a new record with two people, and won the 1,200 franc -wager made with Santos-Dumont and Archdeacon against M. Charron, who -contended that a flying machine would not, within the year, carry two -men weighing sixty kilograms each. On June 6th he flew 20 minutes, 20 -seconds, covering 19.7 kilometers, thus again increasing the world’s -record, and winning the Armengaud prize of ten thousand francs for the -first aviator to remain aloft fifteen minutes in France. On September -29th and October 2d, at Chalons, he successively increased the world’s -record, and achieved his best results for the year. The first of these -trials lasted 42 minutes, covering 24.5 miles; the second lasted 44.5 -minutes, covering 25 miles. This last flight was forty times as long as -the one of January, which gave him the grand prize of fifty thousand -francs, and is a good index of the wonderful progress in aviation -made in France during the year 1908. Between these two performances -he, on September 30th, sailed from Chalons to Rheims, a distance of -27 kilometers, in twenty minutes. This flight was made over trees -and houses, sometimes at an elevation of 200 feet, and was the first -town-to-town flight ever accomplished. The following day he won the 500 -franc prize for height, passing over balloons 82 feet from the ground. -Such was the lively pace Farman set for the rest of the world. - -Mr. Curtiss drifted into the business of building and operating air -ships and flying machines by frequent association with inventors, who -came to his bicycle works at Hammondsport, N. Y., for assistance in the -design and construction of aërial craft. He was particularly sought as -a constructor of propelling mechanism, for he had special skill and -experience in producing light gasoline engines. As a motor expert he -was invited to the laboratory of Dr. Alexander Graham Bell, at Beinn -Breagh, near Baddeck, Nova Scotia, in the summer of 1907. Dr. Bell had -developed his wonderfully light, strong and stable tetrahedral kites -to such an extent that he wished to convert them into “aërodromes” by -applying light propelling mechanism. He accordingly invited two young -Canadian engineers, F. W. Baldwin and J. A. D. McCurdy, to consult -with him regarding the structural details of his proposed flyer, -and contracted with Mr. Curtiss to supply the motive power. These -gentlemen with Lieutenant T. Selfridge, a guest of Dr. Bell, developed -so many independent ideas that Mrs. Bell suggested the advantage of -forming themselves into a scientific organization, at the same time -offering the capital required for experimentation. Acting on this -advice and generous offer, they formed themselves into the now famous -Aërial Experiment Association, whose object was the construction of a -practical aëroplane, driven through the air by its own motive power, -and carrying a man. - -PLATE XXIV. - -[Illustration: THE _RED WING_.] - -[Illustration: CURTISS BIPLANE.] - -[Illustration: CURTISS BIPLANE WITH PONTOONS.] - -After some preliminary downhill glides[48] and studies with a motorless -aëroplane, the association, on March 12, 1908, brought forth their -first dynamic machine, the _Red Wing_, shown in Plate XXIV, in order -to speed it along the ice of Lake Keuka, near Curtiss’s factory; the -purpose being, not to fly, but to test the effect of the vertical -rudder. To the surprise of the twenty-five onlookers, the machine, -after running two hundred feet along the ice, serenely rose into the -air and flew 319 feet. “This,” says Dr. Bell, “was the first public -exhibition of the flight of a heavier-than-air machine in America.” -It is noteworthy also that this machine was completed and ready for -trial in less than seven weeks from the time of starting. Its design, -while embodying suggestions from each member of the association, was -attributed chiefly to Lieutenant Selfridge, who took the leading part -in evolving the plans, and who gave them his final approval, it being -the intention of the association to offer each man a chance to produce -a flying machine after his own notions, aided by the experience and -liberal advice of his fellows. - -As the advantage of flying from the ice had been suggested some years -before the death of Lilienthal, it seems remarkable that this method -did not yield important results earlier in the development of aviation. -A smooth ice field is such an ideal place for testing a dynamic -aëroplane, that previous gliding experience would seem unnecessary, -providing the machines were designed with a fair knowledge of the -elementary principles of stability and control. Even glider practice -could be effectively conducted over a smooth ice field after momentum -had been acquired by aid of gravity, or a tow line. Having sufficient -momentum the aviator could test his rudders cautiously without rising, -then, after a little experience, make short glides in the air, and so -be prepared to install the motor. Landing or falling on smooth ice at -great horizontal speed, from a low elevation, is much less hurtful than -tumbling on the ground, as every bold skater knows from experience. - -The aëroplane II, designed by Mr. Baldwin, aided by his associates -and their combined experience, resembled that of Lieutenant Selfridge -in the trussing of its body surfaces, but was mounted on wheels, and -provided with torsional wing tips for lateral control. When tested, it -was found easy to launch and land, besides responding very promptly to -the three-rudder control. In the hands of Mr. Curtiss, on May 22d, this -aëroplane, called the _White Wing_, flew 1,017 feet in 19 seconds, and -landed smoothly on a plowed field. This at the time was the longest -flight ever made by an aviator in his first trip on a heavier-than-air -machine. - -It was now Mr. Curtiss’ turn to be captain of design and construction. -Under his supervision aëroplane III, called the _June Bug_, was ushered -forth, in the month of honeymoons. It differed from the two preceding -in having a box tail; also in having a nainsook cover, instead of the -red and white silk that characterized the _Red Wing_ and the _White -Wing_. - -After some practice, this flyer behaved so well that it seemed -competent to win the Scientific American Cup offered for a public -flight of one kilometer straight away. Accordingly an official trial -was arranged with a committee of the Aëro Club of America, for the -fourth of July, 1908. It was the first official flight in the western -hemisphere, and proved in every way most satisfactory. The machine -flew 2,000 yards over an S-shaped course at a speed of 39 miles an -hour, displayed admirable control, and had abundant motive power. The -performance was an intimation and augury of the victorious flights to -come the following year. As the Association now repaired to Dr. Bell’s -summer home, the Hammondsport experiments terminated for the season. - -The year 1908 also brought to happy fruition the long and persistent -experiments of Louis Blériot, the most illustrious pioneer and -champion of the monoplane. Beginning in 1900, he had tried one type -after another, of flying machine, till he became world renowned for -his fertility of invention, his daring, his picturesque accidents and -hairbreadth escapes. So long as he was not killed he was certain to -make progress; for he had every endowment that ensures success. He -possessed the energy of early manhood, having been born in 1872; he -had the thorough technical training of the Central School of Arts and -Manufactures, where he graduated in 1895; he possessed extraordinary -talent for invention and constructional detail; he had the prowess, -courage and coolness requisite for testing intractable and dangerous -flyers; he was in the world’s most active center of aviation; he -also had sufficient means. If he was late in achieving success, it -was because he preferred to develop original ideas, and could not be -content with merely copying his predecessors. - -Like many other novices in aviation, Blériot began by trying to build -a machine with flapping wings that should fly like a bird. This was to -be actuated by a carbonic acid motor. In 1904 he abandoned his first -machine, of bird type, and turned to aëroplanes, beginning with a -biplane of the Farman, or Voisin type. His second machine was built by -Gabriel Voisin, one of the most experienced of the pioneer aëroplane -manufacturers. This biplane, unprovided with an engine, was mounted -on floats, towed along the Seine by a motor boat, and rose from the -surface carrying Voisin as pilot. _Blériot III_, composed of elliptical -cells, or sustaining surfaces, and powered with two _Antoinette_ -motors of 25 horse power each, was tested without success on Lake -Enghien during the year 1905-6. _Blériot IV_ was made of quadrangular -cells, and launched at Bagatelle in 1906, carrying a soldier, Peyret; -but crashed to earth in its first trial. Finally in 1907, _Blériot -V_, mounted by the inventor himself, rose into the air and flew -successfully, but was lacking in stability. His sixth aëroplane was -of the Langley type, provided with a 24-horse-power motor, then with -a 50-horse-power _Antoinette_; but it was unstable fore and aft. One -day it traversed 184 meters, then fell from a height of 25 meters and -was shattered on the ground. His seventh was one of the swiftest yet -constructed, attaining a speed of nearly 80 kilometers an hour, and, in -two private trials, covering a distance of 500 meters. Thus seven years -had slipped away, leaving Blériot still in the tentative period of his -work. But now he was at the threshold of a career of brilliant success, -which soon brought him the highest honors at home and throughout the -world. - -After various minor flights in the spring and summer of 1908, Blériot, -on October 31st of that eventful year in aviation, determined to -attempt a cross country voyage, as Farman had done the day before. As -will be remembered, Farman had flown from Chalons to Rheims, above -trees and houses, a distance of nearly 17 miles, thus achieving the -first town-to-town flight in history. Blériot would improve that record -at once, by flying in a closed circuit embracing several villages. - -His renowned cross-country flight was directed from Toury to Artenay, a -village nine miles distant. Mounting his aëroplane _VIII-ter_, at mid -afternoon, in presence of a large gathering, Blériot followed the -course shown in Fig. 40. In the neighborhood of Artenay he landed for a -few minutes. After some slight repairs to his magneto, he reascended, -turned about and headed for home. Half way on his return course he -stopped again for a few minutes, at the Village of Santilly; then -readily reascended and flew to the neighborhood of his starting point. -He thus traveled about 17 miles in a closed circuit. This performance, -with that of Farman the day before, inaugurated the period of aërial -voyages in heavier-than-air machines. It appealed so powerfully to the -sentiment of the community that a monument was erected at Toury to -commemorate the glorious achievement. - -PLATE XXV. - -[Illustration: BLÉRIOT FLYING OVER TOURY-ARTENAY CIRCUIT.] - -[Illustration: BLÉRIOT MONOPLANE _NO. VIII_.] - -[Illustration: BLÉRIOT MONOPLANE _NO. IX_.] - -[Illustration: FIG. 40.—BLÉRIOT’S TOURY-ARTENAY AËROPLANE CIRCUIT, -1908.] - -A fair view of the famous monoplane, in its renowned cross-country -voyage, is presented in Plate XXV. It consisted of a single sustaining -surface firmly attached to a long trussed spine mounted on three -wheels, and carrying at its front end the gasoline motor and propeller, -at its rear end two of the rudders, the third, or lateral, rudder -being placed at the wing terminals. A part of the trussed frame was -covered, to minimize the atmospheric resistance against the framing, -pilot and engine. The vertical rudder at the rear turned the machine -to right or left; the horizontal rear rudder controlled the elevation -and pitching of the machine; the torsional wing tips controlled the -lateral stability, and could be used to cant the aëroplane or check its -listing, as in the Wright and Curtiss machines. The craft exhibited an -easy poise in the air, and possessed good equilibrium, owing to its -arrowlike structure and its three-rudder system of control. It was a -strong rival of the biplanes previously noticed, and a herald of better -things to come. - -In the meantime the Wright brothers had resumed their field practice. -During the month of May, 1908, they tested their famous aëroplane of -1905, provided with increased engine power, and carrying two passengers -upright. A few brief flights were made at speeds of 41 to 44 miles an -hour, showing that all the mechanism was adequate and effective. But on -May 14th a false push on a lever, made by Wilbur Wright, brought the -flyer to earth, wrecking it too badly to be repaired in the few days -available for experimentation. These flights were but preliminary to -the official trials set for the approaching summer; for the brothers -had contracted to furnish one machine to the United States Signal -Corps, another to a French syndicate. - -The Chief Signal Officer of the United States Army in December, 1907, -had issued specifications, and invited bids, for a flying machine -apparently far in advance of the art. The flyer was to carry two men -aggregating 350 pounds, was to remain aloft one hour continuously, and -was to maintain an average speed of 40 miles an hour in a cross-country -flight to and fro, covering a distance of ten miles. The contractor -must instruct two officers to operate the flyer. Furthermore the -machine must be capable of flying 125 miles without stopping. The -requirements seemed severe, even to those well versed in aviation. -Nevertheless two bids were received; one from the Wright brothers for a -biplane to cost $25,000, another from Mr. A. M. Herring for a biplane -costing $20,000. Both bids were accepted for the summer of 1908; but -only the Wright contract was eventually carried out. - -About the same time the Dayton inventors had sold their patent rights -in France to a syndicate in that country. The contract specified -a machine for two passengers, having a speed of 50 kilometers an -hour, and a range of 125 miles. Furthermore, the inventors agreed to -instruct three pupils to manage the aëroplane. The fulfillment of -these two contracts occupied some months, but presented no formidable -difficulties. Though neither of the brothers had ever flown an hour, -and though both were comparatively unskilled as operators, they had -such faith in their invention that they undertook to launch themselves -publicly in untried machines, Wilbur Wright in France, Orville in -America, at about the same time. - -Of these two tests, the one conducted by Orville Wright at Fort Myer, -near Washington, was the most successful at first. After a few brief -preliminary trips, he suddenly astonished the world by phenomenal -flying. On the morning of September 9, 1908, he made a voyage above -the drill ground lasting 57 minutes, 31 seconds, and again in the -evening another flight lasting one hour and three minutes, this time -before a throng of distinguished spectators. Immediately thereafter -he took aboard Lieut. Frank P. Lahm for a flight of six minutes’ -duration. These records were improved day by day, and all things -seemed propitious for the official tests of speed and endurance. -But on September 17th, while sailing with Lieutenant Selfridge at a -height of about 75 feet, a blade of the right-hand propeller struck -and loosened a stay wire of the rear rudder. Instantly the wire coiled -about the blade, snapping it across the middle. Thereupon the machine -became difficult to manage, and plunged headlong to earth, throwing the -men with their faces on the bare ground, fatally wounding Lieutenant -Selfridge, and seriously injuring Mr. Wright. Lieutenant Selfridge did -not recover consciousness, and died within three hours, from wounds -on the forehead and concussion of the base of the brain. Mr. Wright -suffered a fracture of the left thigh and of two ribs on the right -side. The aëroplane was badly shattered in its framing, but the engine -was practically intact. This accident terminated the tests for the -season; but ere long a date was set for their resumption during the -following year. - -PLATE XXVI. - -[Illustration: WRIGHT BIPLANE OF 1908.] - -[Illustration: STANDARD WRIGHT BIPLANE OF 1910.] - -[Illustration: WRIGHT RACING BIPLANE OF 1910.] - -Wilbur Wright began his demonstration for the French syndicate on the -plain of Auvours, ten miles from Le Mans, France, on August 8, -1908. For some weeks his flights were very brief, owing to the balky -condition of his engine; but this difficulty was removed by the middle -of September. After the accident to his brother he remained inactive -for a few days; then, to reassure his supporters, he raised the world’s -record by flying a distance of over 52 miles, remaining aloft 1 hour, -31 minutes, 25 seconds. After this he continued at frequent intervals -to make long flights, quite usually taking a passenger with him, and on -several occasions a lady. His endurance, his altitude, his abandon and -perfect control amazed and delighted Europe. Incidentally he won some -valuable prizes, beating the French records for duration, distance and -elevation. Once he rose to a height of 380 feet. On September 21st, he -flew 42 miles in 1 hour and 31 minutes; on October 11th, he carried a -passenger an hour and ten minutes; finally on the last day of the year -he flew 77 miles in two hours and twenty minutes, thus winning the -much coveted Michelin prize, of twenty thousand francs for the longest -distance flown during the year. It was a triumphal close to the most -progressive and eventful year in aviation—the first year of exhibition -flying, the inaugural year of a noble art. - -Having completed the speed and distance tests at Le Mans by the close -of the year 1908, Wilbur Wright went to Pau, in the South of France, -for the winter practice with his three pupils, Count de Lambert, Paul -Tissandier and Alfred Leblanc. Here on the vast trial grounds at Pont -Long, six miles from Pau, he had a commodious hangar with a workshop -on one side, and on the other, apartments for the aviator and his -mechanics. He arrived with his pupils, on January 14th, and next day -was joined by his brother and sister, who had followed him from Paris, -Orville being now well recovered from his injuries received at Fort -Myer. In a short time the machine was set up, and early in February -began its regular service, having a pair of levers for the teacher and -another pair for the passenger. The pupils quickly acquired the art of -steering, being first allowed to control one lever, with Mr. Wright -holding the other; then being entrusted to manage the whole machine, -with their tutor as passenger; and finally becoming themselves teachers -of the newly acquired art. Only a few hours’ practice was needed to -attain proficiency, the whole time in the air aggregating hardly half a -day for each pupil, though the lessons extended over many days. - -A pleasant feature of the sojourn at Pau and Le Mans was the number -and character of the visitors, and the boundless enthusiasm displayed -toward the new art. Tens of thousands of people from the neighboring -places, and tourists from many parts of the earth assembled to see the -flights; statesmen, military officers, scientific and parliamentary -delegations, representatives of innumerable periodicals. Queen -Margherita, having missed a flight on her first visit to Le Mans, -came a second time, and remained three hours standing on the field, -fascinated by the wonderful aërial equipage. The King of Spain, Alfonso -XIII, who visited the aërodrome at Pau, on February 20th, manifested -the keenest interest and delight in examining the aëroplane and seeing -it fly; first with the pilot alone, then with an extra passenger. He -took a seat in the machine beside Mr. Wright, discussed its working, -and expressed his deep regret that reasons of state prevented him from -making an ascension. A month later the King of England, who was at -Biarritz, adjourned to Pau, where he remained to witness two unusually -fine flights. He expressed the greatest pleasure in the performance, -questioned the brothers about the details of the machine, and -complimented them on their achievement. - -From Pau, Wilbur Wright went to Italy, about the end of March, to -fulfill an engagement to give demonstrations and lessons in the use of -the biplane. He was welcomed at Rome by the King of Italy, on April 2d, -and later gave a public exhibition of flying, to aid the sufferers in -the recent earthquake at Messina. His flights were attended with great -enthusiasm, and his lessons in aviation were quickly mastered; his -pupil, Lieutenant Calderara, soon making public flights alone. A rare -sight it was, this modern winged chariot soaring above the ruins of -that ancient campagna, bearing with it a moving-picture camera. - -By the end of April Mr. Wright had finished his task in Italy, and was -journeying homeward with his sister and brother by way of London, where -they enjoyed the hospitalities of the Aëronautical Society of Great -Britain; and where, on May 3d, the brothers received the beautiful gold -medal of that famous society, the oldest aëronautical organization in -the world. - -The return to America was primarily for the purpose of completing -the official tests at Fort Myer; but incidentally the brothers must -find time to receive new honors and ovations. While in the shop at -Dayton, working vigorously to complete a new aëroplane for the War -Department, in the hope of finishing the demonstrations by June 28th, -the limit of their allotted month, they were showered with attentions -too numerous for their comfort. They must drop their tools in order to -go to Washington to receive the gold medal of the Aëro Club of America -from President Taft, at the White House, on June 10th. On June 17th -they must witness an elaborate demonstration in their honor at Dayton, -where they received a gold medal from the city, another from the State, -and another from the Federal Government. Finally late in June, they -arrived in Washington with the rehabilitated biplane, to make good -their contract with the Signal Corps. - -The early tests of this aëroplane were not an unmixed triumph for the -Wright brothers and their well-wishers. At first the machine failed to -fly completely about the drill ground. It took the air with difficulty, -and came to the earth on the first turn. Some lack of adjustment in the -frame was suspected. The motor was accused of weakness. The launching -weights[49] were too light. The brothers explained that a new flyer -is like a new horse; the driver must learn his idiosyncrasies before -attempting to show him off to advantage. They intimated also that -they would be pleased to have the great throng of prominent people, -who flocked daily to the drill ground, kept away until their flying -instrument was properly tuned for public performances. They discouraged -superfluous attentions. The big legislators who ventured audaciously -to peep into the sacred shed containing the marvelous machine, were -hailed by the military guard, and unceremoniously marched across the -line among the plain people. It was a dreadful shock to these mighty -signors, and many a fat lawmaker cursed audibly, vowing never to vote -a cent for flying squadrons. But still they haunted the drill ground -daily, despite the long journey and the late dinner; for they were -fascinated by the untold and unconjecturable possibilities of the new -art. - -June 28th came quickly, obliging the patient aviators to beg another -extension of time. They were granted thirty days longer, which seemed -to them more than necessary; but in this judgment they were mistaken. -One accident after another delayed the consummation of their official -task of flying one hour above the field, then five miles across country -and return. Finally, on July 27th, Orville Wright, who was making all -the flights, took with him Lieut. Frank P. Lahm, and sailed gloriously -for one hour, twelve minutes and forty seconds, before ten thousand -delighted spectators. It was an ideal summer evening, and all the -maneuvers were performed with excellent poise, security and grace. A -new world’s record was established. Now all the vast throng from the -President and his cabinet to the simplest laborer, appreciating the -achievement as a triumph for America and for humanity, burst forth into -prolonged acclamation and applause. - -The cross-country flight was next in order. The course from Fort -Myer to Alexandria lay over scattered forests and a deep valley. The -flight seemed a difficult and hazardous enterprise; but the brothers, -confiding in their machine, seemed to have little apprehension of -failure or peril. Indeed, they seemed most concerned about the bonus -to be secured by flying at an average rate exceeding the contract -speed of 40 miles an hour; for each additional mile an hour would pay -them $2,500 above the normal price of the aëroplane. They accordingly -declined to fly in any but very calm weather, no matter how vast the -gathering of visitors, or how illustrious. They wished, of course, to -expedite the final and crucial test; but they could not always have -ideal conditions, and would not take undue chances. On the evening -after the endurance test the engine balked, owing to the clogging of a -rubber pipe from the gasoline tank. Dusk came on, and the disappointed -crowd went home to a late dinner. The Secretary of War, who was -present, very kindly granted a third extension of time, covering the -rest of the month. Next evening it was a trifle breezy. Wilbur Wright -announced that the flight could be made, but that the bonus would -be less than on a still evening; he would therefore wait for calmer -weather. Twelve thousand people were turned away disappointed. There -was muttering among the impatient and warm of blood. It was remarked -that the War Department could easily drop these procrastinated -experiments and buy a practical aëroplane in the open market for -$5,000. But the discommoded officers good-naturedly allowed the thrifty -sons of Dayton to have their way in striving for a large bonus, beyond -the normal price of $25,000. - -On the following evening the weather was clear and fairly still. All -was in readiness for the flight to Alexandria and return. Orville -Wright, taking with him Lieut. B. D. Foulois, circled the drill ground -on easy wing, then sailed directly across country for the captive -balloon at Shuter’s Hill. In a few moments they vanished beyond the -forest, and for a while even the most optimistic were doubtful of their -safety. At length they reappeared sailing homeward at very great speed. -The machine proudly circled the drill ground amid thunders of applause, -and landed softly at the lower end, beyond the shed. - -The multitude hastened to congratulate the aviators on their marvelous -performance. For everybody it was a scientific and national triumph; -for Wilbur Wright it was something more. With pencil and pad he quickly -computed the bonus, surrounded by a wall of reporters. “Wise old -Wilbur,” remarked one, “he knows the worth of coin in a crude republic. -While Fame blows her trumpet he counts the solid gain.” The figures -showed an average speed of 42.6 miles, making the bonus $5,000. The -voyage was one of the finest ever executed up to that date; it was -a glorious termination to a long and troublesome, but epoch-making -demonstration. Now there remained only the task of instructing two -officers to fly, and this was leisurely accomplished by Wilbur Wright -in October. - -As shown in Plate XXVI the Wright aëroplane used at Fort Myer in -September, 1908, was a twin screw biplane mounted on skids and having -the three-rudder system of control. The rear rudder turned the machine -right or left, the front rudder raised or lowered it, the warping of -the wings controlled the lateral poise. The turning right or left -could be effected on level wing; but the inventors canted the machine -sidewise, to obviate skidding, or sidewise gliding of the craft, due -to centrifugal force. These three-rudder movements were performed by -three separate levers actuating suitable mechanism; but they could be -performed easily by a single lever having three separate movements, as -preferred by some designers. The aëroplane in launching ran along a -monorail, accelerated by a towrope passing over pulleys, and attached -to a falling weight comprising nearly a ton of iron. The dimensions of -the various parts are given as follows by Major George O. Squier,[50] -the officer in charge of the experiments: - - “The aëroplane has two superposed main surfaces 6 feet apart - with a spread of 40 feet, and a distance of 6½ feet from front - to rear. The area of this double supporting surface is about - 500 square feet. A horizontal rudder of two superposed plane - surfaces about 15 feet long and 3 feet wide is placed in front - of the main surfaces. Behind the main planes is a vertical - rudder formed of two surfaces trussed together about 5½ feet - long and one foot wide. The motor, which was designed by the - Wright brothers, has four cylinders and is water cooled. It - develops about 25 horse power at 1,400 r. p. m. There are two - wooden propellers 8½ feet in diameter which are designed to run - at about 400 r. p. m. The machine is supported on two runners - and weighs about 800 pounds.” - -On the whole the demonstrations at Fort Myer in 1909 did not greatly -enhance the prestige of aviation. They were attended by too many delays -and accidents, and too much waiting for ideal weather. As a consequence -the guardians of the national purse were not clamoring for an aërial -flotilla. Some few, no doubt, understood that the aëroplane could -brave more than a zephyr with safety; but the general public accepted -the demonstrations at their face value. The unthinking multitude did -not realize that with sufficient incentive, such as war presents, -the Wright brothers could repeat those brilliant flights, of the end -of July, under more severe weather conditions. Fortunately, events -were transpiring elsewhere which vastly increased the popular fame -and valuation of the new art. This refers more particularly to those -startling achievements in aviation abroad which were largely stimulated -by competition and prizes. - -After the Fort Myer flights the Wright brothers separated, Orville -going to Germany to represent their interests and give demonstrations; -Wilbur exhibiting at the Hudson-Fulton celebration in New York, and -teaching the Signal Corps officers to manipulate the newly purchased -government aëroplane. As usual, both achieved distinction in their new -fields. At Potsdam, on October 2d, Orville Wright, after a ten-minute -flight with Crown Prince Frederic William, ascended alone, mounting -steadily in circles for fifteen minutes, and reaching an elevation -roughly estimated at 500 meters, after which he descended safely in -five minutes. On September 18th, he made a new record at Berlin by -carrying a passenger, Captain Englehardt, for 1 hour, 35 minutes and 47 -seconds. Wilbur Wright, on September 9th, flew from Governor’s Island, -in New York harbor, to and around the Statue of Liberty, then returned -to the point of departure. On October 4th, starting from the same -point, he flew over the waters of New York Bay and above the Hudson -River to a point opposite Grant’s Tomb, then returned to Governor’s -Island, covering a distance of about 19½ miles in 33½ minutes. The -trip upward was made at an elevation of about 200 feet, through a -stratum disturbed by vortices rising from the steamer smokestacks, and -eddies caused by the northeast wind blowing over the tall buildings. -The return was made at a level of 50 feet on the Jersey side of the -river where the air was less turbulent. He intended later in the day -to make a long flight, but, owing to the bursting of a cylinder head, -he stopped his demonstrations and returned to Washington to finish -his instruction of the Signal Corps officers. This was easy routine, -and it afforded opportunity to try the effect of transferring one of -the forward steering planes to the rear and applying it there as a -fixed horizontal tail, as used by Voisin, Curtiss and others. The new -arrangement was reported to increase the longitudinal steadiness of the -aëroplane, and was used in subsequent Wright aëroplanes. - -The brothers now ceased public flying for a while, to attend to the -business of manufacturing and selling their craft. They formed an -American company, enlarged their facilities for constructing machines, -procured grounds for training operators, and prepared generally to -fill orders both for aëroplanes and for public exhibitions. Not the -least of their labor was to defend their patent claims, which they -wished to be interpreted so broadly as practically to exclude all -flyers whose lateral poise is controlled by changing the angle of -incidence of the wings, or of lateral stabilizing planes. This was -not an easy undertaking, since the torsion wing was a well-known -device, having been described many times in public print, and having -figured in earlier patents and experiments in various countries. To -add to the difficulty, their patent claims apply specifically to the -warping of normally flat sustaining surfaces, the warping of arched -wings having been patented by Prof. J. J. Montgomery, whose invention -antedates theirs.[51] However, if they produced no novel and radical -invention in aviation, they, like Santos-Dumont in aëronautics, were -first to achieve some measure of practical success, by applying a light -automobile engine to a familiar machine in which former inventions -and ideas were skillfully employed. On this ground of practical -success they strove for an interpretation broad enough to establish -a monopoly covering even Montgomery’s rights, which apparently they -were infringing. But when to this end they applied for a preliminary -injunction restraining Curtiss from using his system of control, and -Paulhan from using Farman’s system, they were unable to convince the -court of the justice of their petition, and the injunction suit was -vacated. - - - - - CHAPTER XI - - STRENUOUS COMPETITIVE FLYING - - -The cardinal allurements in aviation for 1909 were the prize offered -for the first flight across the English Channel, and the prizes to be -won at the world’s first aviation meet, scheduled for the last week -in August of that year, at Rheims, France. The desire to win these -honors stimulated to livelier effort the most noted designers and -operators of aëroplanes, all of whose machines were represented at the -great tournament. It also brought into sudden prominence several new -aviators. Young men, little versed in the science or literature of -flight, took to wing, and in a few days found themselves world-famous. -Aërial chauffeurs, skillful and daring, delighted vast throngs of -people, kept the cables warm with news, and incidentally filled their -purses with money. Thus the trade of aëroplane jockey was one of the -interesting products of this eventful year. - -The first half of the aviation season of 1909 brought forth many -improvements which seemed to augur well for the public demonstrations -to follow. Hubert Latham, with the swallowlike _Antoinette_ monoplane, -designed by Levavasseur, the inventor of the _Antoinette_ motor, began -soaring grandly in the sky and into fame. Paul Tissandier, on May 20th -at Pau, established a new French record by flying 1 hour and 2 minutes. -The Voisin brothers were perfecting in detail their boxlike aëroplanes, -noted for inherent stability, and destined to achieve further renown -during the summer, under the dexterous hand of intrepid young Paulhan. -This new and daring young aviator, after a few practice flights, began -making world records. On July 15th, he flew 1 hour, 7 minutes and -19 seconds. On July 18th he made a new world’s record for altitude, -driving his Voisin aloft 150 meters at Douai. Impatient Roger Sommer, -rejecting his own make of biplane, purchased a machine from Farman, -and after a little practice, broke the world’s record for distance on -August 7th, by flying at Chalons, 2 hours, 27 minutes, 15 seconds. Many -others were advancing in skill, and would erelong achieve excellent -results. Most strenuous of all, perhaps, were Curtiss and Blériot, the -champions of high speed, respectively in the biplane and monoplane, and -Farman, the winner of large prizes. - -In the latter part of April, Henri Farman tested a new biplane of -his own design and manufacture, which proved very satisfactory. It -resembled his former craft, but was provided with small balancing -planes hinged to the rear margins of the wings near their tips. -This machine, furthermore, was provided with both landing skids and -wheels, the latter yielding to any unusual stress by means of elastic -connections, so that the skids took up the shock. With this improved -biplane, Farman beat his former records by flying continuously 1 hour, -23 minutes, at Chalons, on July 19th. Four days later he made a new -cross-country record by flying from the Chalons parade ground to Suppe, -about forty miles, in 1 hour and 5 minutes. These flights were gently -suggestive of what might be expected at Rheims the following month. - -During the opening period of the 1909 aëroplane season, Glenn H. -Curtiss brought forth a new biplane, designed for the Aëronautic -Society of New York, with the coöperation of his new partner, Mr. A. -M. Herring, and began active practice for various prizes at home and -abroad. After some brief trials at Hammondsport, N. Y., he shipped his -aëroplane to Morris Park, in order to participate in the Aëronautic -Society’s first flight exhibition of the year. On June 26th he flew, -but without official witness, far enough to win one of the $250 -prizes offered to the Aëro Club of America by its president, Mr. -Cortlandt Field Bishop, for the first four persons who should fly one -kilometer. He now wished to make an official flight for this prize -and also for the Scientific American trophy, a beautiful engraved -silver cup—which he had won a year previously for the first public -flight of one kilometer, made in America, but which now should go to -the person making the longest official flight of the year 1909, not -under 25 kilometers. But the Morris Park race track proved unsuitable -for such contest, being too restricted. He therefore took his biplane -to Mineola, Long Island, where he could practice on a wide plain, and -possibly make some new records. Here a triangular course 1.3 miles long -was staked off, and some short trial flights were made. Then Mr. C. M. -Manly, who was official timekeeper for the Aëro Club of America, was -notified that a trial for the prize would be made. - -The demonstrations near Mineola were most successful, and proved the -beginning of a brilliant summer for Mr. Curtiss. On July 17th he won in -quick succession both of the prizes mentioned above. The trial for the -smaller prize began at 5.15 in the morning and lasted but 2½ minutes, -followed 6 minutes later by the start for the coveted cup. In both -cases the machine took the air with ease and grace, after a 200-foot -run over the rough marsh land. In the cup trial the first twelve -turns, aggregating 25 kilometers, were accomplished in 33½ minutes, -but the machine continued for seven more rounds, and finally landed -in excellent form, just 52½ minutes after it had crossed the starting -line. The actual measured distance flown was 24.7 miles, but the true -distance traversed by the machine was probably 30 miles, making the -time speed between 30 and 40 miles per hour. This was slow, indeed, but -the control was satisfactory. Those who wished for high speed would -find it in the new aëroplane which Mr. Curtiss would presently take to -Rheims for the speed contest, in which he was to fly as sole champion -of the United States. - -The type of machine used by Mr. Curtiss in 1909 was a natural outgrowth -of his previous ones, but very much perfected in power and finish. It -was a biplane mounted on a three-wheeled chassis, two wheels under the -main body and one well to the front, so as to prevent toppling forward. -It was propelled by a single screw at the rear, directly connected to -a water-cooled motor of the Curtiss make. Its flight was controlled -by three rudders exerting torque respectively about the three axes of -the aëroplane, supplemented by two fixed keels, a vertical one in the -front and a horizontal one in the rear. Of the three rudders mentioned, -one in the rear turned the craft right and left, like a boat, one in -the front raised or lowered her, while the third or lateral rudder, -consisting of small horizontally pivoted planes between the wing-ends, -and turning oppositely to each other, controlled the lateral poise. -These lateral rudders, or winglets, used by Curtiss, Farman and others, -are commonly called _ailerons_. - -PLATE XXVII. - -[Illustration: _BLÉRIOT XI_ WITH MOISANT AVIATOR ON MEXICAN BORDER.] - -(Courtesy A. J. Moisant.) - -[Illustration: _BLÉRIOT XII._ - -(Courtesy E. L. Jones.)] - -Louis Blériot with his two new machines, his _No. XI_ at Douay and his -_No. XII_ at Issy-les-Moulineaux, practiced nearly every fine day in -June and July, making fast progress in the art, and achieving some -notable records. By warping the wings he could keep his balance better -than in former years, and dare more severe weather. On June 12th, he -made a straightaway flight of 820 feet in his _No. XII_, taking as -passengers A. Santos-Dumont and A. Fournier, the entire weight being -1,232 pounds. This was the first flight of three passengers in an -aëroplane. On June 25th, despite a strong wind, he circled in his _No. -XII_ eleven times about the parade ground at Issy-les-Moulineaux in 15½ -minutes, maintaining excellent stability. Next day he made 30 circuits -in 36 minutes, 55⅗ seconds, stopping finally because of spark failure -due to excess of oil. On July 4th, at the aëronautic meet at the Juvisy -Aërodrome, for sufferers from the earthquake in the south of France, -he flew in his _No. XI_ for 50 minutes, 8 seconds, at a height of 50 -to 80 feet, finally stopping because of feed trouble in his engine. -This flight was his second up to that date. On July 13th, he made a -new cross-country record by an early morning flight in his _No. XI_ -from Etampes to within eight miles of Orleans, stopping some minutes -en route, to show the practicability of his monoplane. Thirty-five -minutes after landing, his machine was taken apart and shipped back to -his factory at Neuilly, near Paris. After this record he received gold -medals from the Aëro Club of Great Britain and the Aëro Club of France. -He was also awarded the _Prix de Voyage_ of 14,000 francs, of which he -himself received 5,000 as pilot, 4,000 as constructor, while 3,000 went -to the motor manufacturer and 2,000 to the propeller designer. - -The monoplanes _No. XI_ and _No. XII_ represented Blériot’s most -successful types. They bore a family resemblance to his preceding -machines, but had a more vigorous lateral control due to warpage of -their main surfaces instead of the wing-tips, as of old. Both were -provided with a single-screw propeller in front, and both were mounted -on three-wheeled chassis with shock absorbers. The larger machine, or -_No. XII_, had a wing surface of 337 square feet; the smaller a surface -of 151 square feet. The latter, on its historic cross-Channel trip, -carried a three-cylinder air-cooled Anzani engine. - -Hubert Latham, in his beautiful _Antoinette_ monoplane, began to -achieve distinction for himself and his admirably designed long-tailed -flyer early in the spring, and, ere midsummer, was one of the favorite -idols of the thronged aërodromes. He preferred a lofty course; he -cut through the sky with the precision and grace of a winged-spear; -he fascinated the spectators by the steadiness of his sweep. The -French reporters declare they saw him roll and light cigarettes in -full flight. Not only did he delight the artist, but he surprised the -official measurer. Toward the end of May he established a new monoplane -record by a flight lasting 37 minutes and 3 seconds. On the 5th of -June he flew continuously 1 hour, 7 minutes and 37 seconds, at a speed -of 45 miles an hour. This was done in a wind and heavy rain which -drenched and blinded him, finally inducing him to come down. On June -7th he carried a passenger, something new for a monoplane. In July he -increased the altitude record by flying 450 feet high. Next day he -flew across country from Arras to Douai, 12½ miles, in 20 minutes. -Very reasonably, therefore, he announced, his intention of sailing for -England above the waters of the turbulent strait. - -The _Antoinette_ monoplane resembled, at a distance, a long-winged -fish with its head cut off and replaced by a screw-propeller. It had a -skifflike body with the screw in front, followed by the _Antoinette_ -engine, then by the pilot’s seat, the tail part carrying fixed -horizontal and vertical fins and movable horizontal and vertical -rudders. These rudders together with _ailerons_, or warping wings, -controlled the poise in flight. The body was mounted on a light chassis -having cushioned wheels, and a landing skid for absorbing shocks. The -engine employed no carburetor, and was cooled by water which turned -to steam in the engine jackets, condensed in tubes on the side of the -prow, then was pumped back to the jackets. - -PLATE XXVIII. - -[Illustration: _ANTOINETTE_ MONOPLANE OF 1909. - -(Courtesy W. J. Hammer.)] - -[Illustration: _ANTOINETTE_ MONOPLANE OF 1910.] - -The cross-Channel prize, above mentioned, was a cash sum of one -thousand pounds, offered by the _London Daily Mail_ for the first -successful flight from France to England. Many would fain have it, -though the voyage seemed dangerous, if not foolhardy. Of the various -aviators who coveted the prize, Latham and Blériot were the most -strenuous in competing for it. The bold boy tried first. - -Housing his aëroplane on the high cliff facing the Channel near Calais, -Latham looked toward England, impatiently waiting for placid weather, -and a chance to soar. The venture was hazardous. By some it was deemed -rash, owing to the uncertainty of having to alight upon the water, if -the motor should fail. But the brave youth was less alarmed than the -old aviators, who had no intention of competing with him. So, with a -boy’s confidence, he brought forth his huge-winged _Antoinette_, on -July 19th, skimmed along the ground, soared grandly above the high -cliffs, and sped over the waters at a great elevation, as usual in his -aërial voyages. - -Latham’s flight was magnificent, but brief. Owing to spark failure -and the stoppage of his motor six miles from the French shore, he -settled promptly, but skillfully, down upon the sea. When found by -the accompanying torpedo boat destroyer, detailed to follow him from -Calais, he was seated on the aëroplane, serenely smoking, buoyed up by -the great hollow wings. He was quickly brought to shore, undaunted and -eager for another trial; but in the rescue his frail flyer was roughly -handled and very much wrecked. - -Louis Blériot now hurried to Calais eager to attempt the cross-Channel -flight. Placing his little monoplane, _No. XI_, in a tent on a farm -near Calais, he waited an opportune moment to sail. On Sunday, July -25th, he was routed from bed very early by his friend, Alfred LeBlanc, -and taken forth all reluctant to the field, for preliminary practice -before sunrise; for the weather was favorable and he should sail as -soon as the sun arose. Though suffering from a foot burned in a recent -accident, he discarded his crutches and mounted his winged machine with -eager courage, remarking: “If I cannot walk I will show the world that -I can fly.” For some minutes he circled about the ground where, even -at that early hour, many scores of people were assembling. All was now -in readiness; the flyer was in excellent trim, the pilot in buoyant -spirits, and the torpedo boat destroyer, _Escopette_, well out at sea -to escort her swift aërial charge as well as might be. - -The moment of departure had come. Blériot, buttoned in his -close-fitting suit and hood, sat on his white-winged machine, headed -for the cliff, and surrounded by a group of well-wishers. At 4.35 the -light-wheeled craft with propeller whirring, sped along the ground, -rose gracefully in the air and shot bravely over the precipice, with -the hustling aviator on its back. The admiring spectators were wild -with excitement and joy. But there was one sad group in Calais that -morning. Latham and his watchers, who had been waiting for better -weather, rose in time to see his rival on the wing, but too late for -pursuit, as the wind had suddenly risen. The unwary boy remained -behind, weeping with disappointment. - -Blériot was now soaring high over the sea, faring toward Dover without -a guide or a compass. For some time he could observe the _Escopette_ -following him, her great column of smoke obscuring the new risen sun. -Presently both shores vanished, and for ten minutes he could descry -neither land nor signal of any kind. He was sailing over the sea at -forty miles an hour and drifting with the air he knew not whither; but -he allowed his fiery steed to follow its instinct, as a bewildered -horseman does sometimes. Along the horizon now appeared the white -cliffs of the English shore. He was headed not for Dover but for -Deal, carried adrift by the southwest wind. Three boats crossing his -course seemed plying for some port on his left, and hailed him with -lively greeting. He could not well inquire the way, but he followed -the general course of the vessels, soaring high aloft. At length he -saw a man on the cliff violently waving the tricolor, and strenuously -shouting: “Bravo! Bravo!” He plunged in the direction of the signaler, -whom he knew to be his friend M. Montaine. On nearing the earth he was -caught in a violent turmoil of air and whirled about. Wishing to land -at once, he stopped his power sixty feet aloft, and swooped abruptly -down with an awakening thud upon the old English soil, sleeping in the -peaceful sunlight of a Sabbath morning.[52] - -Blériot’s landing was the greatest jolt to British insularity since the -birth of steam navigation. Nevertheless it was welcomed with unfeigned -delight as emphasizing the triumph of a new art which enriches all -people. Shortly afterward was erected on the spot a monument in white -granite having the plan and size of the renowned _No. XI_ monoplane. - -Sportsmanlike, Latham wired his congratulations to Blériot, expressing -the hope to follow ere long. Two days later he flew across the Channel -to within one mile of the English coast, where he had to land in the -water again because of motor failure. This time he struck the sea -violently and suffered a broken nose. His goggles were shattered and -cut his face. - -The big competitive flyers of the world now turned toward Betheny -Plain near Rheims, where the first International Aviation Meet was to -be held August 22-29, 1909. Here was a place to make record flights, -to win rich prizes, and to achieve great distinction. A well-designed -aërodrome had been prepared for the occasion. In the midst of a broad -plain was marked by means of high poles, or pylons, a rectangular -course, measuring roughly one by two miles, or more exactly, 1,500 by -3,500 meters. At one end was the judges stand, the grand stand, the -café and the aëroplane sheds. The numerous cash prizes offered for -speed, for distance, for endurance, for altitude, etc., totaled in -value nearly forty thousand dollars. But the most coveted prize of -all was the James Gordon Bennett Aviation Cup, together with $5,000 -cash, the winner of which should have the honor of placing the next -international contest in his own country. This should be awarded to the -aviator having the best speed over a two-round, or 20-kilometer course. -The next most desired prize was a cash sum of $10,000 for the longest -flight. A special charm of the tournament was that each fortunate -entrant should meet the distinguished aviators from all localities, and -should fly in presence of a world-gathering. Aëroplanes of all the most -successful types were there, numbering together thirty-eight machines. - -The first day of the great aviation week, Sunday, August 22d, was -devoted to elimination trials to determine which aviators should -represent France in the race for the Bennett trophy. Of the seventeen -entrants in these trials the three who should cover two rounds of -the course in the shortest time should be selected as champions, the -next six, in order of speed, to act as reserve pilots. But owing to -the severe weather of that day, only six of the seventeen entrants -succeeded in flying well enough to be admitted in either capacity. -Of these six the cup champions were: Blériot, Lefebvre, Lambert and -Latham; the reserve champions being in order, Tissandier, Paulhan and -Sommer. These men won their places by bold flying in rough conditions; -for rain had fallen heavily during the previous night, and the wind -was still blowing in swift and gusty current over the sodden field. -Indeed, the weather seemed anything but propitious at the opening of -that great experimental tournament, on the success of which should be -based the estimates and forecast of so many subsequent meets. Swift -clouds overhead, and black flags displayed on high masts, indicated -that flying would be impossible. A passing storm raged at five o’clock -in the afternoon. But toward evening the face of Nature brightened, -and with it the hopes of the aviationists. The weather at last became -ideal. Nearly all the aëroplanes came forth, and at six o’clock no -fewer than seven were on the wing at one time. Some of them were -doing most startling feats. Lefebvre would make a threatening swoop -at the grand stand, then circle swiftly away. Blériot, in a moment of -unsteadiness, charged a wheat stack with his swift monoplane, damaging -his sharp-bladed propeller. Count de Lambert sailed under Paul -Tissandier, heedless of the aërial wake beneath. The crowds applauded -and cheered every novel and bold maneuver. The closing hour with its -sunny calm atmosphere and its vivacious well-pleased populace, presaged -greater joys for the morrow. Sir Henry Norman, who was present, -declared that those events marked the birth of a new epoch in human -development. - -Monday, the second day of the meet, dawned fair and calm, with -promise of settled weather. It was the last qualifying day for -the ten-thousand-dollar long-distance prize, the Grand Prix de la -Champagne. No one who had not flown a reasonable space on, or before -Monday, could take part in the trials for that coveted honor on -Wednesday, Thursday and Friday. The aviators were about early, and many -had qualified before evening. Several of the pilots tried for speed -records. Blériot, with an 80-horse-power monoplane, made one round of -the course in 8 minutes, 42⅖ seconds. Curtiss, in his 60-horse-power -biplane, lowered the time to 8 minutes, 35⅗ seconds. This was an -achievement of the greatest concern, since Curtiss stood alone, as -champion of America, against the more experienced flyers of Europe. -He thought of nothing, engaged in nothing, except the speed trials, -for in these he hoped to win, with his 60-horse flyer, even against -renowned Blériot, in his 80-horse machine. Other interesting events -were designed solely to entertain or amuse the people. Lefebvre again -furnished merriment by sweeping over and under, and around Paulhan, who -was flying at an elevation of 25 feet. M. Kapferer had navigated from -Meaux, in the dirigible _Colonel Renard_, and sailed about the grounds, -with fine effect. - -Tuesday should have brought ideal conditions and performances; for it -was the day set for the visit of M. Falliéres, President of France. -But the morning was dark, with ominous clouds gathering over the -aërodrome, and black flags streaming in the strong wind. When the -President arrived, though the clock told four, no flying had yet begun. -He examined the machines, held an informal reception, and at five took -his box in the grand stand. Presently Bunau-Varilla in his Voisin -biplane, rocking in the fifteen-mile wind, flew past, waving his hat to -the distinguished spectators. After him came dauntless young Paulhan -who also passed the President, shortly before the latter, with his -party, returned to the railway station. He flew at an elevation of 300 -to 500 feet, his Voisin heaving and lurching in the tumultuous wind, -like a boat on the breakers. He had no lateral stabilizing plane, so -he let his box kite rock. The people were appalled, but what cared he -for wind gusts, so far from earth? Let the craft roll and pitch; he -was not uneasy. On the return lap he raced and beat a railway train. -These were but inklings of what he would do with increased experience. -Latham followed presently on his long swift monoplane, to the delight -of all who love the graceful in mechanism and motion. Ere long he -was chased and overhauled by Blériot, in his cross-Channel flyer. -This was exciting, but Blériot produced still greater enthusiasm by -beating the speed record, lowering it to 8 minutes, 4⅖ seconds, for -one round of the 10-kilometer (6.21 mile) course. The day was ended, -and the spectators were charmed again by the spectacular evolutions -of Lefebvre, who cavorted in the air before the grand stand, cutting -impressive curves and figure “8’s.” - -Wednesday morning, the fourth of the meet, was heavy with black clouds, -which presaged unfavorable weather. The winds were light, but still -nothing transpired till late in the afternoon to break the monotony -of waiting. During this long interval the crowd could amuse itself -with gossip, refreshments and music, and with an occasional flight of -lesser moment. About four o’clock Paulhan set forth in a six-mile wind -to try for the Grand Prix de la Champagne. His lumbering Voisin had -a speed of hardly more than thirty miles an hour, but it was driven -by a very reliable 50-horse Gnome 7-cylinder motor, whose body spins -round a fixed crank, carrying the propeller with it. No one at first -expected a very long flight. The wind rose, sometimes exceeding 20 -miles an hour, tossing the young pilot terribly, and once throwing -him so far within the course that he must turn a complete circle in -order to round the corner post, or pylon. But he kept right on, so -long as there remained a drop of fuel. He first broke Wilbur Wright’s -best record, by 23 minutes, then Sommer’s recent record, by 6 minutes, -finally landing, at half past six o’clock, with a new world’s record -of 82 miles in 2 hours, 43 minutes and 24⅘ seconds. The people were -frantic with excitement; they clapped their hands and waved thousands -of handkerchiefs; they rent the air with tremendous applause as he -was borne toward the grand stand on the shoulders of his clamorous -comrades. Others at the same time had been flying with varied fortune. -During Paulhan’s long demonstration, Fournier had encountered a -miniature whirlwind, turned over in the air, at a great height, and -crashed sidewise to the ground, with some injury to his nose, and with -much damage to the wings and tail of his machine. Latham, wishing to -lower his circuit time, flew thrice around the course, but without -improvement. During his flight, a splendid rainbow appeared, which -together with the _Antoinette_ dragon fly soaring high aloft with -Latham on its back, produced an impressive spectacle. - -Thursday morning brought fine weather and the promise of an eventful -day. As a consequence serious efforts were made to excel all previous -records, particularly for speed, duration and distance. In the forenoon -Latham flew 43.5 miles in the _Antoinette XIII_. In the afternoon Count -de Lambert, in his Wright biplane, flew 72 miles. Blériot entertained -the throng by carrying Delagrange as passenger; but while sailing near -the ground he encountered some dragoons, turned sidewise to avoid -striking them, and plunged into a fence, breaking his propeller. But -the great sensation of the day was Latham’s afternoon flight for the -Grand Prix, in his _Antoinette No. 29_. Starting with plenty of fuel -and favorable weather, he rose to a high level and flew till his supply -was exhausted, at times encountering rough winds and for a while -plowing through a rainstorm. It was the banner flight of the week thus -far; for it surpassed all other long ones in distance and speed, though -not equaling Paulhan’s in endurance. His total range, when compelled -to alight through exhaustion of fuel, was 95.88 miles, in 2 hours, -18 minutes, 9⅗ seconds. This showed an average speed of 41.63 miles -an hour for the whole distance, while the speed for his first round -was 44.65 miles an hour. For this great achievement he could thank -his 50-horse, 8-cylinder _Antoinette_ motor, one of the lightest in -existence, for that power. - -Friday, August 27th, was the last day allotted for the distance, or -Grand Prix contest. After the wonderful new records of Paulhan and -Latham, people were marveling what might happen on the final day. Many -assumed, of course, that Latham’s record of 96 miles would remain -unsurpassed. At four-thirty, Latham started on another long flight, in -his _Antoinette_ monoplane _No. 13_, followed presently by Farman and -Sommer in Farman biplanes; these flying six to twelve feet from the -ground, with gallant Latham soaring aloft nearly three hundred feet in -his swift long-winged fish, and occasionally gaining a lap on them. -Sommer stopped after three rounds, because of motor trouble. Latham’s -fuel gave out after a voyage of 68.35 miles, and he glided to earth. -Farman continued to plod along on his slow, low-wandering craft, with -little attention. Others were in the air, with biplanes and monoplanes, -entertaining the populace—Blériot, Curtiss, Delagrange, Tissandier, -Bunau-Varilla—these had the applause. Presently the spectators -remembered that ground-skimming Farman had been a very long time on the -wing. He now became the center of rapt attention. Slowly he distanced -Paulhan’s great world’s record of Wednesday; slowly he distanced -Latham’s greater world’s record of Thursday; but still he plodded away. -The sun sank on his flight; darkness came on the field, so that he -vanished from view at the far end of the course. At the close of the -nineteenth round he landed in the dark before the grand stand, limp -and exhausted, having journeyed 3¼ hours and traversed 118.06 miles. -For the second time he had won a $10,000 prize; nineteen months ago by -flying 1 kilometer, to-day by flying 190 kilometers. A searchlight was -thrown upon him. He was pulled from his machine and carried upon the -shoulders of his friends, receiving a prolonged and tremendous ovation. - -The seventh morning of the tournament, Saturday, August 28th, -came with a beaming smile, promising good flights and a pleasant -termination of the glorious cup contest for the highest speed in two -rounds of the 10-kilometer course. The air was calm, mild and hazy -above the Betheny plain. The flyers were in fine mood for great -achievements. The thronging groups of well-dressed men and women -awaited further startling events, with varied animation and constant -chatter. The day was well diversified with interesting flights; but, -of course, not with long ones. The chief interest centered in the -leading cup-champions—solitary Yankee Curtiss and great Blériot with -his 80-horse monoplane, supported, if need be, by his allies in the -contest, Lefebvre and Latham. - -Curtiss, shortly after ten o’clock, made a preliminary trial, lowering -his best anterior time. With this he was so pleased that he prepared -immediately for the one official flight allowed in that contest. He -filled his small gasoline tank, replenished his radiator, signed a -legal paper certifying this to be his trial for the cup, and at once -took wing, circling before the grand stand, then crossing the line at -full speed. The biplane pitched perceptibly at its unusual gait, but -turned the corner in easy curves, completing the first round in 7.57⅖, -the second in 7.53⅕; the total time being 15 minutes, 50⅗ seconds, and -showing an average speed of 47.04 miles an hour. - -About noon Blériot came forth with his 80-horse monoplane _No. 22_, -which was expected to eclipse the Curtiss biplane, but in reality -proved exasperatingly slow. At two o’clock he tried another propeller, -with little encouragement. An hour later he tried again with a -four-blade propeller, but descended before completing the round. After -tinkering for an hour, aided by several mechanics, he flew to his shed, -shortly before five o’clock. As no start was allowed after five-thirty, -he hastened zealously and started his official flight at five-ten. The -mighty monoplane cut the air at terrific speed, without pitching, or -rolling, and finished the first round in 7.47⅘, or 5⅔ seconds less -than Curtiss’ best lap. The overjoyed French throng rent the air with -frantic bravos! Curtiss and Mr. Bishop were silent, appreciating the -skill of that fiery antagonist, with his monster engine. As the steady -birdlike craft turned the last pylon, and swept homeward in magnificent -career, the timers called out the seconds. The throng listened with -abated breath and then with alarm. Blériot had lost speed in the -second round. When he crossed the line his total time was 5⅗ seconds -greater than that of his only rival. The conqueror of the Channel, the -champion of France, was defeated and the international trophy must go -to America, won by a taciturn, calculating Yankee, never before seen in -Europe, and hardly known to fame. - -Other official flights for the cup during the day were made by Latham -and Lefebvre for France, and by Mr. Cockburn, champion for England, -the latter bird-man sailing into a stack of wheat in the middle of -his first round, then wheeling to earth. Incidentally Henri Farman -established a new world’s three-man duration distance and speed record -by carrying two passengers ten kilometers in 10 minutes 39 seconds. -Thus ended the chief day of the tournament, leaving the contestants in -the following order of speed: Curtiss, Blériot, Latham, Lefebvre. - -Of the other leading prizes, that for the fastest single round was -taken by Blériot; that for the fastest three-round flight was won by -Curtiss on Sunday, with a record of 23 minutes, 29 seconds for the -thirty kilometers; the Altitude Prize was won by Latham, who attained -an elevation of 508.5 feet; the Prix des Mecaniciens was won by -Bunau-Varilla in a flight of 100 kilometers; the Prix des Aëronats -was won, on Sunday, by the large dirigible, the _Colonel Renard_, -in a voyage of 50 kilometers, or 31.06 miles, at an average speed of -24.9 miles an hour. Along with the chief prizes, many smaller ones of -considerable value were awarded, thus summing up the total of $37,000. - -The small band of men who organized the first international aviation -meet, with the Marquis de Polignac as president, and the great wine -merchants of the Champagne district as their supporters, were now -elated and triumphant. They had undertaken a novel and costly sporting -enterprise, regarded by many as hazardous, or rash, even though -sanctioned by the Aëro Club of France. For an enormous attendance -would be required to meet the expense of preparations and prize money. -It was doubtful whether the few available aviators could draw large -crowds to Betheny for a week, even in ideal weather, and there was risk -of sending the critical populace away displeased if abundant flights -were not made. The whole event might prove a painful fiasco, if rains -and high winds should predominate; for were not aviators notoriously -reluctant to fly in rough weather? Vain apprehensions, ignoring the -reckless and intrepid daring of the Gallic sportsmen! Nothing short of -a week’s continual tempest could have kept them down. - -The great tournament was a triumph, not only to the courageous -promoters, but also to the aviators, the manufacturers, the whole of -mankind. It astonished both actors and spectators. It marked a new -epoch in the art of aëroplaning. It inaugurated a magical and wholly -novel kind of recreation and public amusement that should be demanded -at once in all civilized countries. It eradicated, in a measure, the -inveterate notion that the aëroplane is essentially a fair-weather -machine. With a cheap instrument capable of flying scores of miles -in rain and wind, what applications might not come, of the greatest -import to the world? - -The fashion set at Rheims was imitated in other cities. Before the -close of the year 1909, aviation meets were scheduled for Brescia in -Italy, Berlin, Juvisy, near Paris, Blackpool and Doncaster, England. -The succeeding year was to have more such events than the really -capable aviators could attend. In both hemispheres, sums in cash, -equaling or exceeding those at Rheims, would be offered by many -prominent communities, eager to witness such novel and thrilling -entertainment as only dexterous aviators could furnish. But it would be -learned also that considerable financial risk attends an aviation meet, -unless good judgment mark the choice of site, season, pilots and the -executive agencies. Several of the meets following the one at Rheims -succeeded neither in defraying expenses nor in furnishing competent -aviators to repay the trouble of holding the tournament. The meets -held in England were practically failures. A most interesting flight, -however, was performed by Latham in a wind of 25 to 35 miles an hour. -This itself was a very impressive achievement. The Brescia meeting was -remarkable for the turbulence of its aërial currents and for Rougier’s -record high flight of 645 feet. - -The two most wonderful flights in the autumn of 1909 were those of -Count de Lambert and Farman. During a meet at the Juvisy aërodrome, -Lambert, on October 18th, after circling the ground a few times on a -Wright biplane, attaining a height of 450 feet, started for Paris, -steadily ascending in the direction of the Eiffel Tower. Circling this -at an altitude of about 1,300 feet, he returned to Juvisy at 5.30 -P.M., having journeyed 30 miles over that dangerous route, in about -50 minutes. This indicated that lofty flying might enable one to -pass safely over a city, even with an unreliable motor, since, if the -propeller stopped, a glide of many thousands of feet could be made, to -choose a landing. Farman’s flight was less spectacular, but quite as -marvelous. On November 4th, while competing for the Michelin trophy -for the longest distance traversed in 1909, he flew continuously for -4 hours, 6 minutes, 25 seconds, voyaging in that time 144 miles, at -an average speed of 35.06 miles an hour. This proved to be the record -distance-and-endurance flight for the year. Other men spoke of sailing -all day in a machine carrying ample gasoline, but failed to make good -their words. - -PLATE XXIX. - -[Illustration: ESNAULT-PELTERIE MONOPLANE, EARLY PATTERN. - -(Courtesy W. J. Hammer.)] - -[Illustration: ESNAULT-PELTERIE MONOPLANE OF 1910.] - -Unheralded, but quite astonishing, were the flights of Santos-Dumont -in September, 1909. Though conspicuous as a pioneer in aviation, he -for a while had been absorbed in other affairs, and had not kept pace -with his brother aëroplanists in France, since his bold and brief -dashes into the air in the early days of the art. During the season of -1909, however, he developed a surprisingly small and simple monoplane, -spreading 102 square feet of wing surface, and weighing in complete -running order, 259 pounds. It was driven by a Darrac motor, mounted -above the main surface, carrying the propeller directly on its shaft, -and having radiator tubes along the inner surface of the main plane. -Its triangular trussed frame was wheel-mounted, and tapered rapidly -to the rear, terminating in horizontal and vertical rudders. With -this tiniest flyer he sailed across country from St. Cyr to Buc, 4¾ -miles, in five minutes, at the unprecedented speed of 55 miles an -hour, repeating the performance several times, according to report. He -also left the ground after a run of 60 feet, in an unofficial trial. -Characteristically, he presented to the public the scale drawings of -his machine, with all rights to its use. - -A very original type of monoplane was developed by Robert -Esnault-Pélterie, who began experimenting in 1903. As shown in Plate -XXIX, its body frame was covered to reduce air-resistance, and was -provided with ample keel surface to promote directness and steadiness -of flight. The weight was borne on two wheels in tandem, aided by -wheels at the wing tips to preserve the lateral balance when the -machine was resting. When under way the lateral poise was controlled by -wing warping; the motion about the other two axes being controlled by a -horizontal and a vertical rudder, the latter being “compensated,” that -is, having its axis near the center of side pressure, when in action. -An air-cooled motor of 30 to 35 horse power with a direct mounted -four-blade screw formed the propulsion plant. Though the “R. E. P.” -aëroplane, as it was commonly called, did not achieve great distinction -at first, due, perhaps, to the inventor’s being over original, and -making all its parts himself, instead of buying some high-class engine -and propeller, as other successful aëroplanists had done, still his -machine was greatly admired by technicians for its excellent finish and -the fastidious, thorough and patient manner in which its young inventor -labored to make it perfect, both in design and construction. It was -regarded as a future record breaker, which, indeed, it was destined to -become on further improvement. - -Although little was accomplished in building aëroplanes in other -countries than America and France, up to the beginning of 1909, that -year witnessed some good flights in homemade machines in Germany, -England and Canada. In November, 1909, Herr Grade, in Germany, made -a flight of 55 minutes in his monoplane. Mr. S. F. Cody, who -constructed a biplane for the British army, flew over forty miles -across country on September 8th, high above trees and buildings, -remaining on the wing for 63 minutes. The machine spanned 52 feet, -weighed with the pilot, nearly a ton, and was controlled by front -and rear vertical rudders and two lateral rudders, well in front, so -geared that if worked oppositely the machine listed, while if worked -identically it rose or fell. In Canada Dr. Alexander Graham Bell and -his associates continued the experiments, already described, begun -in 1908 by the Aërial Experiment Association. In 1909 their fourth -machine, the _Silver Dart_, flew many times round a course on the -frozen lake, Bras d’Or, traversing, all told, about 1,000 miles in 100 -flights. - -PLATE XXX. - -[Illustration: GRADE MONOPLANE. - -(Courtesy E. L. Jones.)] - -[Illustration: CODY BIPLANE.] - -The last months of this strenuous year, 1909, and of the first decade -of dynamic flight, closed without further startling developments. True, -some records were made, but they merely pleased, not perturbed the -world, now accustomed to marvels. Be it recorded, however, that, with a -Voisin biplane, Paulhan, on November 1st, flew 96 miles in 2 hours, 20 -minutes, and on November 20th flew 1,960 feet high in a Farman biplane; -on December 9th, Maurice Farman, mounted on his own type of biplane, -rode through the icy atmosphere from Buc to Chartres, a distance of 40 -kilometers, in 50 minutes, the longest town-to-town flight up to that -date; and on December 31st he flew from Chartres to Orleans, a distance -of 41.6 miles, in forty-six minutes. But several fine achievements -which the world anticipated for that year remained unattempted. The -great prize flight of 183 miles from London to Manchester was still -untried, though several machines and pilots seemed equal to the voyage, -and $50,000 would be awarded by Lord Northcliffe to the brave aviator -who should accomplish that journey in not more than three stages and -within a period of twenty-four hours. Neither had anyone yet flown -to an elevation of one kilometer. These tasks were left over as -allurements for the succeeding year. - - - - - CHAPTER XII - - FORCING THE ART - - -The decade that inaugurated dynamic man-flight had closed without fully -demonstrating the capabilities of such aëroplanes as had been so far -developed. No considerable altitude record had as yet been achieved. No -very long cross-country flight had yet been attempted, though for many -months the New York _World_ had offered $10,000 for the first aërial -voyage from Albany to New York, and the London _Daily Mail_ had long -offered $50,000 for a flight from London to Manchester. The uses of the -aëroplane for scouting by land and sea had not been tested, much less -its probable value in aggressive warfare. Such experiments were for -the immediate future, as also the development of specialized types of -machines for racing, for climbing, for burden bearing, for distance, -for endurance, for landing on water, for rising from water, for -protection of passengers from severe weather. To air men and spectators -alike the future of the art promised to be quite as captivating as the -past. - -The first startling achievements to usher in the new decade were the -great altitude flights. New world records followed in rapid succession -all through the year 1910, with marked persistence and wonderful -progress. Levels that had been regarded as the peculiar region of motor -balloons were passed one after another, until the aviators vanished -beyond the clouds, their limbs palsied with cold, and their aëroplane -wings whitened with frost. Though the greatest prizes were not offered -for this species of flight, and frequently none at all, it had an -abiding fascination for both the flyers and the public. At the same -time it proved to be as safe as it was theatrical and popular. - -The starter in this exciting race for cloudland was Hubert Latham, -already the official holder of the world’s altitude record. At Bouy, -on January 7th, in presence of official witnesses, he rose in his -_Antoinette_ monoplane, describing a great upward spiral till his -barometer recorded 1,050 meters; then returned to earth with like ease -and precision, landing softly near his hangar, before his assistants, -transported with enthusiasm. He had touched the goal of Gallic -ambition, having driven his aëroplane to the height of one kilometer. - -Latham’s tenure of the world’s altitude record quickly passed to -his doughty rival, Louis Paulhan. At Los Angeles, on the twelfth of -January, Paulhan, mounted on a Farman biplane, ascended 4,165 feet, as -against Latham’s record of 3,444 feet. This was a great step upward, -due not only to Paulhan’s prowess and dexterity, but also to the -science and constructive skill of the less spectacular gentlemen in the -designing room, workshop and laboratory. - -Latham strove again for the world’s altitude record and gained it on -July 7th at the second Rheims tournament, by driving his _Antoinette_ -to a height of 4,541 feet.[53] But again his victory was soon eclipsed; -for two days later, Walter Brookins at Atlantic City ascended 6,175 -feet in a Wright biplane. An American was thus the first to fly above -one mile, as a Frenchman had been first to pass the 1-kilometer limit. -The 2-kilometer and 2-mile elevations were exceeded before the close of -the year, as shown by the following table, which also manifests a fair -distribution of honors among various nations and types of machines: - - --------+------------+------------+---------------+------------ - Feet | Aviator | Aëroplane | Place | Date - --------+------------+------------+---------------+------------ - 3,445 | Latham | Antoinette | Betheny Plain | January 7 - 4,165 | Paulhan | Farman | Los Angeles | January 12 - 4,541 | Latham | Antoinette | Rheims | July 7 - 6,175 | Brookins | Wright | Atlantic City | July 9 - 6,604 | Drexel | Blériot | Lanark, Sc. | August 11 - 8,271 | Morane | Blériot | Havre, France | September 3 - 8,406 | Chavez | Blériot | Issy | September 8 - 9,104 | Wijnmalen | Farman | Mourmelon | October 1 - 9,714 | Johnstone | Wright | Belmont Park | October 31 - 10,499 | Leganeaux | Blériot | Pau | December 9 - 11,474 | [54]Hoxsey | Wright | Los Angeles | December 26 - --------+------------+------------+---------------+------------ - -Such lofty flights have proved a severe test of both the aëroplane and -the pilot. In the lighter atmosphere the engine must turn the propeller -at higher speed to secure the same thrust, and the aëroplane must sail -faster to support the same weight as at the lower levels. Thus more -power is required on high, though the explosive medium, being less -dense, is less capable of exerting power. The driver has, therefore, to -jockey his machine with assiduous care and alertness, at a time when he -is least fitted for exertion, owing to fatigue, cold, and it may be, -physical discomfort due to the great change of atmospheric pressure. -But still, both aëroplane and pilot are capable of ascending well above -any levels thus far attained. - -After the triumphant altitude flights of 1910 the aëronautical -skeptics could no longer contend that the aëroplane was useless in -transportation and warfare, because of its inability to fly above -high land or the usual range of the guns of battleships and coast -fortifications. Most of the important mountain passes lie below 10,000 -feet. The safe elevation for motor balloons menaced by terrene guns is -taken to be much less than two miles, and in military practice they -usually operate below the one-mile level. The aëroplanes, therefore, -may not only cross mountain ranges, but may also scrutinize, or -grievously molest, land forces, marine squadrons and perhaps even the -great gaseous cruisers of the atmosphere, which they can far outspeed, -and may even destroy. - -The increase in speed of flight during 1910 was also quite remarkable. -The official record by which Mr. Curtiss won the Bennett Aviation -Contest at Rheims, in 1909, showed a speed of 47.04 miles an hour. -Still higher velocities, ranging from 50 to 60 miles an hour, were -reported later in that season from England and France. In 1910, -however, at the Rheims aviation meet, Morane, with a Blériot monoplane, -covered the 20-kilometer course in 12 minutes 45.2 seconds, or at an -average speed of 66.2 miles an hour, showing a gain of forty per cent -on Mr. Curtiss’s speed of the preceding year. Still better was achieved -at the international tournament held at Belmont Park in 1910. Le Blanc -in a 100-horse Blériot monoplane, especially designed for speed, -covered nineteen laps of the 5-kilometer course at an average rate of -61 miles an hour, and his fastest lap at the rate of 71.68 miles an -hour, thus exceeding Curtiss’s speed of the previous year by fifty per -cent. Other spurts during the latter part of 1910 were reported to have -attained nearly 80 miles an hour over a closed circuit, though perhaps -not a level one. The best results were achieved with machines having -high power engines, small surfaces and slight forward resistance. - -The advance in long-distance flying in 1910 more than kept pace with -the progress in speed. The best achievement at the close of the -preceding year had been Farman’s flight of 144 miles at an average rate -of 35.06 miles an hour in a closed circuit. At the Rheims aviation meet -in 1910, Jan Olieslaegers, in a Blériot monoplane, driven by a Gnome -engine, covered 244 miles in a rectangular course, at an average speed -of 48.31 miles an hour. At Buc, on the 28th of October, an aviator of -three months’ practice, Maurice Tabuteau, in a Maurice Farman biplane, -driven by a Rénault engine, flew over a closed circuit, covering 288.8 -miles at an average speed of 47.9 miles an hour. At Pau on December -21st, M. G. Leganeaux, in a Blériot monoplane, flew for the Michelin -Cup, covering 516 kilometers or 320.6 miles in six hours and one -minute, or at an average speed of 53¼ miles an hour—a splendid showing. -Finally, at Buc, on December 30th, Tabuteau, flying for the annual -Michelin prize, covered 362.66 miles in a Maurice Farman biplane with -an 8-cylinder 60-horse Rénault motor. The average speed in this very -long flight was 47.3 miles an hour, or practically the rate by which -Curtiss won the international contest of the preceding year. Of course -a considerably better showing of both distance and velocity could have -been made on a longer course. - -The world records for cross-country flying and for endurance and load -illustrate both the increasing perfection of the machine and of the -pilot’s skill and confidence. At Los Angeles, on January 19th, Mr. and -Mrs. Paulhan, in a Farman biplane, flew together 21 miles overland from -the aviation field to Redondo and Hermosa Beach and return. On January -31st Van der Born made a world’s duration record with a passenger on -a Farman biplane, flying 1 hour 48 minutes 50 seconds. On March 5th, -Henri Farman, who had previously twice broken the world’s duration -record for a pilot with two passengers, set a new and astonishing -pace at Mourmelon, by carrying Mr. Hevardson and Madame Frank in -easy flight for 62.5 minutes on his new biplane. In France, on April -3d, Emile Dubonnet on his _Tellier_ monoplane flew from Juvisy to La -Ferte-Saint Aubin, a distance of 109 kilometers or 70 miles in 1 hour -and 50 minutes, thus winning the ten-thousand-franc prize offered -by _La Nature_ for the first straightaway flight of 100 kilometers -to be effected in less than two hours, over a previously indicated -course. This fine record voyage was achieved in a machine never before -thoroughly tried. At Chalons-sur-Marne, on April 8th, Daniel Kinet, -a Belgian, mounted with a passenger on a Farman biplane driven by -a 50-horse Gnome engine, broke the world’s record for duration and -distance for two persons by flying round a closed circuit 2 hours 19¼ -minutes, covering a distance of 152 kilometers, or 94 miles. On April -17th, H. Farman, with a passenger in his biplane, voyaged from Etampes -to Orleans, 28 miles. Next day, Paulhan, mounting the same machine, -flew 108 miles, and the following day 42 miles. This tour established a -new cross-country record for total distance, for single stage distance -with one passenger, and for duration and single stage distance with two -passengers. During the same month Farman made a new record for four -passengers by carrying three gentlemen for 1 hour and 4 minutes on his -new biplane, spreading 47.6 feet. On June 9th, two French officers, -Lieutenant Fequant piloting and Captain Marconnet observing, flew -on a Farman biplane from Bouy to Vincennes, 145 kilometers, in two -hours and a half, thus breaking the world’s cross-country distance and -duration record for a pilot with a passenger. On June 13th, Charles K. -Hamilton, in a Curtiss biplane, flew from New York to Philadelphia, a -distance of 86 miles in 103 minutes, and returned the same day, thus -completing 172 miles in one day. This was an exhibition flight made for -_The New York Times_ and the _Philadelphia Ledger_, for a sum reported -to be $10,000. It was a sequel to Glenn H. Curtiss’s memorable flight -on June 5th, down the Hudson River from Albany to New York, for the New -York _World’s_ $10,000 prize. Hamilton’s average speed was 50 miles -an hour going and 51 miles returning. On August 29th, at Lille, Louis -Bréguet is reported to have carried with him on a biplane of his make, -five passengers, who, together with the gasoline, weighed 921 pounds. -It may be added that the Bréguet biplane of that date was advertised -and guaranteed to carry a cargo, or extra load, of 250 kilograms. It -thus appears that by 1910 the aëroplane had grown powerful enough for -an aërial cab service, and that it could carry sufficient explosive -gelatine to derange a battleship. - -The contest for cross-country records continued unabated all that -memorable year. During the first three days of September, Jean -Bielovucic, a youth of twenty-one, mounted on a new type of Voisin -biplane, with but a few days’ practice, flew from Paris to Bordeaux, -covering 540 kilometers, or 336 miles, in four stages, comprising -altogether 6¼ hours on the wing. In spite of severe weather, at times, -he beat the regular express train and established a new world’s record -for cross-country straightaway distance flying with stops. On August -17th, Alfred Le Blanc, finished a six-stage tour round a hexagonal -circuit northeast of Paris, with the finish at Issy, near Paris, -covering a total distance of 785 kilometers, or 440 miles, in 12 -hours 56.4 seconds effective time. On September 7th, Weyman flew with -a passenger from Paris to Clermont near the Puy de Dome, covering -205 miles in one day, while trying for the Michelin prize of 100,000 -francs, for a flight to the Puy de Dome inside of six hours. On -December 18th, Thomas Sopwith, competing for the longest flight across -the Channel and into Belgium, on a British-built aëroplane, flew from -the Isle of Sheppy across the Channel, and landed at Beaumont, Belgium, -covering a distance of 174 miles in 3.5 hours. At Buc, on November -27th, Laurens, in a 60-horse R. E. P. monoplane, flew with his wife 53 -miles at an average speed of nearly 50 miles an hour. On December 22d, -Lieutenant Cammerman, a French army officer, won the L. Weiller prize -by flying across country with a passenger, 147 miles in 4 hours and 2 -minutes. - -These are but a few of the records which serve to illustrate the -progress in cross-country flying during that year of strenuous and -world-wide popular demonstrations. But the bare numerical statement of -facts can give no conception of the delight and exultation aroused in -millions of souls who witnessed or learned of these marvelous human -achievements. They were the advancing triumph of a proud and fortunate -generation, happy in realizing one of the fondest dreams of the ages. -Often during one of these cross-country flights the aëroplane was -accompanied by a swift railway train whose passengers were delirious -with enthusiasm. The entire route was thronged with people assembled -from afar. It was a general holiday for all the fortunate cities and -villages along the way. Mills and factories blew their whistles and -forgot the serious business of life, homes were deserted, schools -were dismissed; the whole population for the time congregated in -the open; bearded mechanics in their aprons, bare-armed housewives -holding their children aloft, girls and boys with wondering eyes, all -shouting, waving banners, throwing up hats, and hailing with tumultuous -demonstration that strange and huge-winged creature gliding from -horizon to horizon with the steadiness, precision and directness of a -mighty projectile. But beyond stating the records of this season of -aërial wonders, only a passing notice can be given to some of the more -conspicuous events. - -The most famous overland voyages of the season 1910 began with the -race for the London _Daily Mail_ prize of $50,000, offered by Lord -Northcliffe for the first person who should fly from London to -Manchester, 183 miles within twenty-four hours, with not more than -two stops. An Englishman, Claude Grahame-White, comparatively new in -the pilot’s art, was first to undertake that difficult and perilous -adventure. Starting from London, without competitor, on April 24th, he -flew in his Farman biplane, from London to Rugby, thence to Hademore, -about halfway to Manchester, landing at a quarter past nine o’clock -at night, after a four-hour trip, and hoping to reach Manchester next -day. But during the night his aëroplane, which was left in the open, -was damaged by the wind, thus necessitating repairs and a new start. On -April 27th, while he was strenuously mending and adjusting his biplane -for a new start, Louis Paulhan, who the day previously had arrived from -France with a Farman biplane to enter the contest, was also vigorously -setting up and adjusting his machine. - -At half past five in the afternoon, Paulhan suddenly set out for -Manchester. Mr. White, who was much fatigued and expecting to start on -the morrow at dawn, after much-needed rest, learned toward six o’clock -that his rival was on the wing, and hurriedly sailed from London, -hoping by skill and good chance to overtake the flying Frenchman. -The race was now the most exciting event in the world. The first -flyers of France and England were competing for the greatest prize -yet offered in the history of aviation, competing in a most modern -and extraordinary race, attended with abundant danger and hardship. -The contestants were evenly matched in mechanism and capability, but -the Frenchman had gotten the march on the unwary Englishman. Paulhan -followed the Northwestern Railway, at times outracing the special -pilot train carrying his mechanics and supplies. At ten minutes after -eight o’clock, he landed at Lichfield, having covered 115 miles. Mr. -White had landed five minutes before eight near Roade, after flying -fifty-nine miles. - -Next morning, Paulhan sailed away at a quarter past four. Mr. White, -hoping to overtake him, had started at dead of night and covered -twenty miles before Paulhan had started. It was a heroic effort, but -unavailing. At twelve minutes after five, Mr. White landed at Hademore, -having completed two thirds of the entire journey. Twenty-five minutes -later Paulhan landed on the outskirts of Manchester, greeted by a -thousand persons. He had covered the whole distance in 4.2 hours, and -had fulfilled all the essential conditions for winning the great prize. - -The next world-famous aëroplane voyage was that of Glenn H. Curtiss for -the New York _World’s_ prize of $10,000 for the first aërial journey -from Albany to New York, allowing two stops. Aviators had been yearning -for this prize since the previous year, but had been too timidly shying -at the dangers of the route. After most careful preparations for this -voyage, Curtiss, bearing a letter from the Mayor of Albany to the -Mayor of New York, sailed away at seven o’clock on Sunday morning, May -29th, accompanied by a New York Central special train, bearing his wife -and a few friends and newspaper men. He landed an hour for supplies -and adjustment at Camelot, 41 miles down the river, and thence flew to -Spuyten Duyvil, at the northern extremity of New York, having completed -the required distance, 128 miles, in 2 hours and 32 minutes, or at the -rate of 50.52 miles per hour along the course. An hour later, he flew -down the river to New York Harbor and landed on Governor’s Island, -where he received a becoming ovation. - -Perhaps the most exciting incident of the voyage to Mr. Curtiss was his -transit of the Storm King Mountain. As he was flying through the narrow -gap at this place he caught the down-rolling air on one side more -than on the other, and dropped very suddenly sidewise 30 or 40 feet. -By shifting his front control, he quickly gained headway and promptly -righted his machine. - -Commenting on Mr. Curtiss’s average speed of 50 miles an hour and his -rugged course, _Aëronautics_ makes comparison between his voyage and -Paulhan’s great prize flight as follows: - - “Paulhan took 4 hours 12 minutes elapsed time to cover 183 - miles when he won the _London Mail’s_ $50,000 and made it in - two stages of 117 and 66 miles each. The 117 miles were covered - in 2.39, a rate of nearly 44 miles per hour. A night’s sleep - intervened and the remaining 66 miles were covered in 1.23, a - rate of nearly 48 miles per hour. The average for the above - was 44.37 miles per hour. Paulhan could have landed at almost - any time and started again, whereas Curtiss could not have - started if he had had to land in the water, and for the whole - distance there was scarcely a suitable space for landing on the - ground, as for nearly the entire way rocky, wooded hills with - precipitous sides line the river.” - -The most audacious and marvelous aëronautic exploit of the year was the -flight of George Chavez across the Alps from Brig to Domodossola, in -his attempt to win the prize of 70,000 francs offered by the Italian -Aviation Society for the first aëroplane flight from Brig to Milan, a -distance of 75 miles. From the nine volunteers for this contest who -presented themselves to the committee in charge, five competitors -were selected, and these for several days made tentative efforts to -scale the lofty pass, but were baffled by the wind or fog. Finally at -one-thirty, on September 23d, the conditions being favorable, Chavez -rose, from Briegen-Berg, in his white-winged Blériot, spiraled upward -1,000 meters, circling around the vast amphitheater of the mountains, -and in nineteen minutes appeared in magnificent career well above the -Simplon Pass, probably 7,000 feet above the sea, whence he glided -grandly down the Italian slope, parrying the rude cross winds and -finally reaching Domodossola, where the enthusiasm was at its climax. -Here he expected to land on a level spot to replenish his supplies, -thence proceed over the easy remaining two thirds of his journey. But -though the perilous pass had been crossed so successfully, disaster -appeared in the valley when least expected. As the aëroplane was -gliding thirty feet high over the level tract chosen for landing, it -met a sudden gust, its wings collapsed, and it fell crashing to earth, -pinioning its brave pilot under the débris. - -Poor Chavez suffered severe wounds about the face and head, had both -legs broken, and for some moments lay unconscious. But he was soon -revived by his friends and taken to a hospital, where he died four -days later. Thus ended the career of a brave and most promising youth -of twenty-three. He had taken his pilot’s license only in February, -1910, yet had established a new world’s record on September 8th, by -driving his Blériot to an elevation of 8,406 feet. He was of Peruvian -parentage and born in Paris. - -The exact nature of the accident was never ascertained, but it was -surmised that the sudden starting of his engine preparatory to landing -overstressed some part of the structure already fatigued from hard -usage. However this be, the committee recognized that Chavez had with -excellent skill covered all the really difficult and dangerous part -of this journey. Accordingly they very generously waived the exact -letter of the rules, and awarded him one half the prize, though he had -completed but one third of the journey. - -Quite as dangerous, spectacular and brilliant as the flight across -the Alps, though less arduous, was Hubert Latham’s aërial voyage over -Baltimore. On previous occasions cross-city flights had been made, -but never one of such length or one executed under such exacting -conditions. At various times aviators had flown above Paris, Rome, -Berlin, etc. On October 14th Mr. White had flown across Washington, -landing on a narrow street between the White House and War Department; -on October 15th Leganeaux had flown above Paris with a passenger; but -these were short flights over an uncharted course. Latham’s voyage -was unique; for he had to follow a long and a prescribed course over -the business section and closely built residence portion of the city. -This great exploit was an exhibition flight made on the invitation -of the _Baltimore Sun_ for a sum of $5,000. It was to be made at the -time of the Baltimore aviation tournament at Halethorpe, Md., and was -calculated to be seen by half a million people; for the whole city was -to be notified and would cease its usual activities to witness the rare -and hazardous demonstration. - -The voyage was triumphant and glorious in every feature. Starting from -the aviation ground, seven miles south of Baltimore, about noon on -November 7th, Latham drove his beautiful _Antoinette_ about the field -in an ascending spiral, like some imperial bird taking its bearings; -then, chart in hand, deliberately sailed away over his elaborately -prescribed journey. This was a figure 8 course with its bottom at the -aviation field and its center at the _Sun_ Building in the heart of -Baltimore, the whole length being 22 miles. As the long-winged bird -in majestic poise, with the intrepid rider on its back, approached -in the distance, soaring 1,000 feet above the gleaming waters of the -Chesapeake, the great bell of the City Hall sounded a mighty peal, and -the whole populace responded in tumultuous chorus; whistles, bells and -a myriad voices mingling their heartiest welcome to the bravest of -aviators. With arrowlike speed and directness he rounded the center of -the course at the _Sun_ Building, then looped the vast northern half of -the city, flying a thousand to three thousand feet high, more easily -to parry the surging eddies of the northwest wind; rounded again the -center of his course and then returned to the aviation field, where he -landed with infinite coolness before the excited throng of applauding -spectators, whose acclaim was all too feeble to express their mingled -wonder, admiration and delight. The voyage lasted forty-two minutes and -fulfilled perfectly every minute requirement, including a short circle -and salutation before the home of Mr. Ross Winans, an invalid gentleman -who had solicited this unique favor, and rewarded it with a gift of -$500. It was the climax of the aviation week at Baltimore. - -Among the many brilliant flights of that memorable year of strenuous -piloting will long be remembered the voyage of the Hon. C. S. Rolls to -Calais and return without landing, and that of Mr. Sopwith, already -recounted; the splendid flight of Mr. Clifford B. Harmon in his Farman -biplane from Mineola, Long Island, to a small rounded island before -his house on the Connecticut shore, for the trophy offered by _Country -Life_ to the first person who should fly across Long Island Sound; -Henri Farman’s flight of December 18th, for the Michelin long-distance -prize, covering 288 miles, and establishing a new endurance record of -8 hours 23 minutes; Mlle. Helene Dutrieu’s flight of December 21st, -for the Coupe Femina, covering 103¾ miles in 2 hours and 35 minutes -in a Farman biplane. Interesting, too, were the first attempt to fly -from Paris to Brussels with a passenger, when Mahieu and Manihé on -starting were brought to bay by a vicious dog which violently attacked -the propeller and was cut in two; and when Loridan and Fay landed on a -tree, from which they descended by a ladder. After this followed the -glorious voyage of Henri Wijnmalen, the youthful and many-sided Dutch -sport, for the prize of 150,000 francs offered by the Automobile Club -of France for the quickest aëroplane trip not exceeding 36 hours, with -a passenger from Paris to Brussels and return. This voyage of some -320 miles was valiantly accomplished by Wijnmalen and his companion -Dufour, in a day and a half, of 13.2 effective hours, and in weather -for the most part windy or tempestuous. Finally to the foregoing list -of splendid achievements must be added the glorious voyage of John -Moisant, who in August flew with a passenger, by compass, from Paris to -London, though he had never been over the route before and had only -just learned to use an aëroplane. - -The International Aviation Tournament of 1910, held at Belmont Park, -Long Island, October 22d to 31st, was the most prominent and eventful -meet of the year, and the second of its kind in history, as the -meeting of the preceding year at Rheims was the first. The present -meet was conducted by the Aëro Corporation, Limited, of New York, -under the auspices and official sanction of the Aëro Club of America, -representing the Federation Aëronautique Internationale. - -This tournament was the annual aërial Olympic contest of the world, and -should have been indicative not only of the aviator’s skill, but also -of the state of national progress in the science and art of aëroplane -construction. Unfortunately, however, for the prestige of the most -deserving nations, the rules of the International Aëronautic Federation -did not confine the contestants to the use of home-built machines, to -prevent the glory of winning the international contest from passing to -the nation which merely furnished the operator, a person who might be -an illiterate jockey, and representative of a country wholly devoid of -science. As luck decided, however, the highest honor in 1910 was won by -a first-class French machine driven by a first-class English aviator. - -In some respects the raw material and working elements of this meet -were most satisfactory. The site is near the wealthiest and most -populous center in America. The grounds are spacious and level, -and provided with all the equipment of a great race course; the -transportation facilities by carriage and by rail from the heart of -New York are adequate to every requirement. The personnel of the -meet comprised the most experienced and most devoted members of the -Aëro Club of America, the oldest and strongest aëronautical body in -the western world, and the only one representing the International -Aëronautic Federation. It is true the season was late and the weather -would probably be cold and tempestuous; the management was burdened by -a costly license, whether just or unjust, imposed upon it as the price -of immunity from patent litigation; the remaining time, after the final -placement of the meet, was all too short for the myriad preparations -to be made. But whatever the obstacles, physical or financial, the -personnel was paramount, and naturally made the huge tournament a -glorious triumph. It was the cardinal sporting event of the year. - -The status of aviation was well represented in both pilots and -machines. Twenty-seven aviators were entered on the program, many of -them world famous. Of these Alfred Le Blanc, Hubert Latham, Emile -Aubrun were the formidable champions of France in the contest for the -James Gordon Bennett aviation trophy; Claude Grahame-White, James -Radley, A. Ogilvie represented England; while Walter Brookins, J. A. -Drexel, Charles K. Hamilton were enlisted as defenders of the coveted -cup and of American prestige. All told, the aviators brought with them -nearly two-score machines, ranging in capacity from 30 to 100 horse -power. Of these about half were monoplanes and half biplanes, for the -most part of French and American manufacture. - -The prizes and remuneration awarded to the contestants were on a -scale proportionate to their skill and number. All told the winnings -aggregated more than $60,000. Further appropriations were made to -cover the expenses of the aviators, and a further sum equal to about -forty per cent of the winnings was paid for immunity from prosecution -for possible infringement of an unlitigated patent. Considering the -immense expenditures for buildings, for policing and other incidentals -of the meet, it may be readily inferred that there was an ample -deficit, and that the air men as a whole were much better rewarded -than some of the sportsmen who gave so much time and labor to the -organization of the tournament. - -A conspicuous feature of the meet was the display of hardiness and -skill of several of the aviators in facing the cold and tempestuous -weather. This was particularly characteristic of Latham in his -_Antoinette_ monoplane, and of Ralph Johnstone and Arch Hoxsey in -Wright biplanes. On October 27th Latham flew round the regular course -for an hour when it was nearly impossible to turn the pylons against -the fierce wind, while Johnstone and Hoxsey performed lofty altitude -flights in a powerful gale which carried them backward, sometimes at -the rate of 40 miles an hour. As a consequence they landed in the -open country, remained overnight and returned next day. Johnstone was -carried backward to Holtsville, 55 miles east of the aviation grounds, -and Hoxsey was blown to Brentwood, 25 miles away, both landing at dusk -in open fields, and both having attained great elevations: Hoxsey, -6,903 feet; Johnstone, 8,471 feet. - -An interesting novelty of the aviation week, at least to Americans, -were the erratic Demoiselle monoplanes, invented by Santos-Dumont and -piloted by Garros and Audemars. These aëroplanes were notable as having -the pilot under the sustaining plane, and the engine above with its -direct mounted propeller. The lateral stability was enhanced by a low -placement of the center of mass, and by a slight dihedral inclination -of the wings. Furthermore, as there was not much leverage or surface in -the rear double rudder, the flight was more stable than steady, like -that of a propelled parachute. In fact, the little monoplanes pitched, -rocked, and fluttered about so like huge butterflies as to provoke -constant merriment. They gave a faint suggestion of how ludicrous -aëroplane clowns could be made by one who has genius for such things. - -Barring the stormy voyages above mentioned, the most memorable events -of the tournament were the Gordon Bennett speed contest, the Statue of -Liberty race and Johnstone’s great altitude flight. Of the numerous -other performances little need be said, except that they contributed -to the general success of an elaborate and most interesting program. -They served the daily need of a costly tournament; they delighted vast -throngs of spectators whose admission fees helped to promote the aërial -sport; but they did not of themselves have more than local interest, or -constitute an advance in the records of first-class achievement. - -The chief race of the meet, the James Gordon Bennett speed contest, -was scheduled for Saturday, October 29th. The prize of $5,000 and the -coveted cup were to be awarded to the pilot who should make the best -average speed in 20 laps over a 5-kilometer course, aggregating 100 -kilometers, or 62.14 miles. The winner should have the distinguished -honor of taking to his own country the next annual contest for the -precious speed prize. - -Grahame-White, England’s foremost aviator and strongest hope in -the contest, brought forth his untried 100-horse Blériot in the -calmest part of the day, and took wing a quarter before nine. He -flew with steady poise and swift, well-sustained speed, completing -the 100-kilometer distance in 1 hour 1 minute and 4.7 seconds, at an -average speed of 61 miles an hour. - -Le Blanc, the most likely winner of all, sailed at nine o’clock. He was -mounted on a 100-horse Blériot with nearly flat wings, the swiftest -monoplane of French manufacture. He was the boldest, sturdiest and -most dexterous pilot in a nation of renowned aviators, the winner of -unnumbered trophies, the “Vainquer de l’Est.” He now flew at unwonted -speed, establishing new world records at every round of the course. It -seemed evident to the timers that only an accident to this impetuous -Frenchman could retrieve the glory of England and save that of America. -Suddenly the accident came. In the last lap, when victory seemed -assured, the gasoline failed; the monoplane shot downward, knocked off -a telegraph pole, and, with broken frame and engine, fell crashing -to earth, entangling the brave aviator. Le Blanc was cut and bruised -about the forehead, and was taken to the hospital to be bandaged, -not seriously injured but in a towering rage, suspecting that some -trickery had given him a shortage of fuel. He had lost the day, though -his average speed for the whole flight was 67 miles an hour as against -Grahame-White’s speed of 61 miles. - -No well-tried machine was available to defend the American prestige. -Curtiss had constructed a new monoplane designed for speed, but though -he had brought the cup to America, he was not chosen as one of its -three defenders. The little Wright biplane of 61 horse power had -flown a few minutes with great velocity, and was looked to with some -confidence. Mounted by Walter Brookins, it set out with tremendous -speed, but had only well started when the cylinders began to miss fire. -Brookins turned toward the infield to land, struck the ground with -terrific shock and tumbled violently on the field beside his broken -machine. He, too, was taken to the hospital for treatment, but was not -seriously injured. - -It was now granted that Grahame-White would be the ultimate winner. -Other aviators attempted to defeat him, but lacked either the necessary -speed or endurance. The cup was accordingly taken from the nations -that had done the most to develop the practical art of aëroplaning. Of -these two nations, the one most deserving of victory, by virtue of its -more careful preparation, was defeated by an extraordinary mishap, when -victory was at hand; the other failed perhaps for want of preparation -rather than from lack of manipulative or constructive skill. - -Of the various highly coveted stakes the largest in monetary value was -known as the Thomas F. Ryan Statue of Liberty Prize. This was a cash -sum of $10,000, to be awarded to the properly qualified contestant who -should fly from the aviation ground to and around the Statue of Liberty -in New York Harbor, and return in the shortest time, the airline -distance being 16 miles each way. The prize was founded by Mr. Thomas -F. Ryan, whose son, Allan A. Ryan, was Chairman of the Committee on -Arrangements of the tournament, and who though suffering with pain and -ill-health, labored so indefatigably to insure the success of the event -so germain to the aëronautical prestige of his country. - -The Statue of Liberty race occurred on Sunday afternoon, October 30th, -beginning just after three o’clock. Count De Lesseps in a 50-horse -Blériot monoplane led the race, followed three minutes later by -Grahame-White. They passed toward the southwest in perfect poise and -vanished beyond the horizon unchallenged by an American contestant; -for Moisant, the American champion, had shortly before injured his -racing monoplane, and the other American racing machines had been -damaged the week before, or had not yet been fully tested. But with -admirable enterprise, Moisant telephoned Le Blanc, in New York, who -was not racing because of the accident to his 100-horse Blériot the -day previously, and offered the Frenchman $10,000 for his 50-horse -Blériot monoplane. The sale was effected in time for the race that -day. But for all that the enterprise seemed futile; for as Moisant -was preparing to start, the others were returning, Grahame-White well -in the lead, having overtaken De Lesseps. As these two aviators were -receiving the applause of innumerable spectators and the felicitations -of their friends, audacious Moisant, the impetuous soldier of fortune, -and hero of the famous flight by compass from Paris to London, started -toward the declining sun, just after four o’clock. He was determined -to win by superior skill and daring. His prudent competitors had -followed a circuitous southern route interspersed with landing places; -but he flew like a maniac straight over the church spires and crowded -buildings of Brooklyn, guided to his goal by a compass, rounded the -Statue of Liberty at a great altitude and plunged homeward with all -possible speed and directness. The megaphone announced his progress, -which indicated some hope of victory so little expected and so much -desired by the vast throng that stood gazing toward the western sun. -In headlong career the swooping monoplane shot by the judges’ stand, -circled and softly landed on the field, triumphant by 43 seconds -over the 100-horse Blériot of Grahame-White. As the intrepid aviator -approached the vast and delighted throng of spectators to acknowledge -its noisy and tumultuous ovation, he was met by the chiefs of the -tournament, draped in an American flag, and paraded before the grand -stand, “which shook in its effort to do honor to the little air -conqueror.” Ultimately, however, the prize was awarded to Count -De Lesseps, because Moisant had failed to qualify properly, and -Grahame-White had fouled the initial pylon. - -The final day of the tournament was made memorable by Johnstone’s -altitude flight. The best previous record was that of Wijnmalen to an -elevation of 9,104 feet, made at Mourmelon, France. Johnstone ascended -on a small Wright machine with powerful propellers adapted to rapid -climbing, determined not only to surpass Wijnmalen but to exceed, -if possible, the ten-thousand-foot level, and win the special prize -offered for such achievement. He actually rose to the great elevation -of 9,714 feet, but could not develop power enough to continue upward. -On his descent he fully exhausted his fuel at 3,000 feet, and thence -glided to earth, landing softly, 1 hour and 43 minutes from the time of -starting. - -Thus the greatest tournament of the year terminated with fine new -laurels for the science and art of aviation; for the spectacular -pilots and for the unseen men behind them—the scientific men in the -laboratories, the designing rooms and the workshops. New standards had -been established in speed, in altitude, in prowess and daring. In these -elements, the spectators could hardly ask for a better exhibition. What -is it to the onlooker to have an aëroplane go higher than the cumuli, -since at that level a thousand feet makes no perceptible difference? -What more could he wish in dexterity of manipulation and audacity in -braving the elements? One thing more, doubtless, and that is, security -and precision of flight in stormy weather. When these improvements -shall have been effected much will have been added to both the sportive -interest and practical utility of the aëroplane. - -The most businesslike and crucial flying contest of the year was the -famous “Circuit de l’Est,” organized by the Paris _Matin_. It was a -competitive voyage over an irregular hexagonal course, lying generally -northeast of Paris, and having its vertices at various cities to the -east and north of the national capital. The main prize offered by -the _Matin_ was one hundred thousand francs for the first air man to -complete the entire course, doing the first side of the hexagon on -August 7th, and the succeeding sides in regular order on successive -odd days of the month, the place and hour of starting each stage -being assigned in advance. Various subsidiary prizes aggregating -nearly a hundred thousand francs more, were available for meritorious -performances at the various stages and stopping-places along the -route. But there were also penalizations for those contestants who -failed to start on schedule time and observe the rules of the course. - -[Illustration: FIG. 41.—MAP OF THE “CIRCUIT DE L’EST.”] - -The race began at Issy, near Paris, on August 7th, with eight aviators -on the wing—Le Blanc, Aubrun, Leganeaux, Mamet, Lindpainter, Weyman. It -terminated August 17th, headed by Alfred Le Blanc on his Blériot, and -followed by Emile Aubrun on a Blériot, then by Weyman on a Farman, all -three driven by Gnome engines actuating Chauvière propellers. Le Blanc -completed the tour of six stages, covering an air-line distance of 488 -miles, in 12 hours’ effective flying, or at the average rate of 40.6 -miles per hour. - -This long tour on schedule time over a rough and varied country in -face of fog, wind and rain, was a most severe trial of the prowess and -endurance of the brave pilots who had the hardiness and pertinacity -to complete the voyage. Needless to add that it created unbounded -enthusiasm among millions of people who witnessed the event, or read of -it, and that the clocklike precision of the “grand raid” inspired new -confidence in the practicability of the aëroplane. - -A particularly impressive feature of the event was that many of its -participants, the aviators, government officers, and members of the -controlling committee, assembled at Issy and other posts of duty, -not by rail, but by aëroplane, sailing across country from many -directions and from great distances. This matter-of-fact procedure led -many persons to believe that the period of mere demonstrations had -approached its close, and that the epoch of practical utility was at -hand; that after marveling so much at the aëroplane, with mingled faith -and skepticism, people would next calmly turn it to practical use. - -Though the progress in designing and constructing aëroplanes in 1910 -did not keep pace with the wonderful advance in new records, still the -inventors and manufacturers continued industriously to perfect the -details of their best standard machines, and in a few instances to -make radical innovations. The perfection in details of construction -manifested itself in the public performance of aëroplanes, particularly -in their greater reliability and their increased capabilities. The -radical innovations were mainly experimental, and not generally -exhibited, though none the less important for all that. Chief of these -perhaps were the hydro-aëroplane developments of Fabre in France, and -of Mr. Glenn H. Curtiss in America, which enabled the aviator to launch -into the air directly from the water and to alight safely on the water, -thus virtually adding a new and very important domain to the empire of -dynamic flight. - -Curtiss, in 1909, succeeded in landing his aëroplane safely on the -water of Lake Keuka, first with sheet iron cylindrical floats under -each wing, and a simple float well to the front of his protruding -chassis, then with a hydroplane surface to the front as being more -effective than the float. But when he attempted to glide up from the -lake with this arrangement, he could not entirely clear the surface, -though his aëroplane under the powerful thrust of her aërial screw, -very nearly lifted from the water. Then he planned to use hydroplane -floats, of hollow wing form, and of such size that they would buoy up -the machine when at rest, and during motion would skim over the water -like a skipping stone, till the biplane should acquire sufficient speed -to rise by the dynamic reaction of the air. In the successful execution -of this plan, however, he was anticipated by Fabre, who made the first -successful flight from the water, on March 28th, 1910, at Martigues, -France. But the Frenchman was not left to bear the palm alone. Early in -the year 1911, Mr. Curtiss rose and landed successfully on the water at -San Diego Bay, Cal., by means of a single float like a flatboat placed -centrally under his biplane, seconded by small auxiliary floats at the -wing ends. A full account of these valuable contributions to aviation -is given in Appendix V. - -PLATE XXXI. - -[Illustration: FABRE HYDRO-AËROPLANE. - -_Photo E. Levick, N. Y._] - -[Illustration: PAULHAN HYDRO-AËROPLANE. - -_Photo E. Levick, N. Y._] - -[Illustration: MOISANT METAL MONOPLANE. - -(Courtesy A. J. Moisant.)] - -As shown in Plate XXXI, Fabre’s hydro-aëroplane was substantially a -monoplane mounted on three richochet floats. It was propelled by a -screw at the rear, and controlled in flight by the usual three-torque -system, in this case consisting of horizontal rudders in front, -vertical rudders front and rear, and suitable mechanism for twisting -the wings. The floats were hollow to give them static buoyancy; they -were curved fore and aft like wings, to give them dynamic lift, both in -water and in air; they were elastically constructed with thin veneer -bottoms and flexibly attached to the framing, so as to endure the -severe buffeting, at high speeds, against the uneven water surface; -they were capable of landing the machine safely on a sandy beach or -meadow, as well as on the water. Indeed, a plan was conceived for -rising and alighting on land and water indifferently. - -[Illustration: FIG. 42.—DIAGRAM OF CURTISS HYDRO-AËROPLANE. -(_Scientific American._)] - -The first machine weighed in flight 950 pounds and spread 280 square -feet of surface, giving a loading of 3.4 pounds per square foot. It was -driven by a 50-horse Gnome engine actuating a Chauvière propeller 7.5 -feet in diameter. In the trials of March 28th, the machine cleared the -water at a speed of 34 miles per hour, and flew about one-third of a -mile, at an elevation of two to three yards; then at the will of the -operator it alighted softly on the water. - -The structural design of the Fabre monoplane was novel and unique, not -to say radical. The wing framing consisted of a single Fabre trussed -beam with ribs attached like the quills of a bird, over which was -stretched the light sailcloth cover, then laced to the beam. The girder -itself was formed of two ash planks eight inches wide by one-fourth -inch thick trussed together by flat steel plates zigzagging trelliswise -between them. As all parts of the beam cut the air edgewise it offered -very little resistance, while at the same time being very strong. The -ribs being attached only at one end allowed the sailcloth to be quickly -slipped on and off for washing and proper care. - -The characteristic features of Fabre’s wing construction were adopted -by Paulhan in his novel and picturesque biplane shown in Plate -XXXI. Trussed beams were used for all parts requiring considerable -stiffness, the longitudinal ones being covered with fabric to reduce -the resistance. The wings whose solid ribs were fastened only at their -front ends were quite elastic, a quality conducive to stability, as -long taught by writers[55] on aviation. In addition to the front -rudder, there was at the rear a horizontal rudder with a vertical one -just before it. To reduce the air resistance further the pilot and -passenger were to sit tandem in a torpedo-shaped car with the 50-horse -Gnome engine and fuel tank back of them. Beneath the longitudinal -girders were two Farman skids flanked with the usual wheels, -elastically connected. The machine, besides flying well, was readily -demountable. The wings could be quickly removed, thus allowing the -biplane to enter a door fifteen feet wide. The entire machine could be -packed in a case 15½ feet long by 3¼ feet square, the whole case cubing -less than six solid yards. Hundreds of them, therefore, could be stowed -away in an ocean cruiser. - -The flying quality of adequately designed flexible aëroplanes is well -illustrated by the swallowlike monoplane shown in Fig. 43. This airy -creation of the distinguished Austrian engineer, Igo Etrich, came into -public prominence in the spring of 1910, though it had been developing -privately for half a decade or more. On May 14th, near Vienna, it -carried pilot Illner 84 kilometers in 80 minutes, at an elevation of -300 meters, thus surpassing all previous Austrian records for distance, -duration and altitude. Its successor, _Etrich IV_, had wing tips still -more turned up, and possessed such stability that during the meet at -Johannisthal in October, Illner circled the pylons with his hands off -the warping levers. At times he wheeled round curves of only ten meters -radius, the whole machine tilted at an alarming angle, yet maintaining -its poise with the natural ease and grace of a soaring albatross. - -The prominent feature of Etrich’s monoplane was the elastic -construction of its wings and tail. Across the rigid main bars of each -wing were fastened numerous ribs with bamboo terminals, thus making -the rear margin and tip of the wing flexible. Similarly the tail, or -horizontal rudder, was framed of bamboo. Hence the pilot, by use of -control wires, could flex both the wing margins and the tail up and -down at will, to steer the machine, or he could let go the controls and -allow the distorted surfaces to spring into their normal positions, -and the machine to pursue the even tenor of its way. Moreover, the -gusts and whirls in the air, on striking the elastic rear margins of -the tail and wings, exert a propulsive effort. Thus could be utilized -the wind’s energy of turbulence, as indicated by the present writer -in 1893, in a paper on “Windgusts and Their Relation to Flight,” -published in the _Proceedings of the International Conference on Aërial -Navigation_ of that year. In passing it may be remarked that many other -aëroplane designers, notably Bréguet, have emulated Mr. Etrich, though -unconsciously perhaps, in providing elastic ribs, hinges or pivots to -permit the rear parts of the wings and tails of their machines to yield -freely to intentional or unusual impulses, and then spring back to -their normal positions. - -[Illustration: FIG. 43.—THE ETRICH MONOPLANE OF 1910.] - -The carefully elaborated monoplane of Robert Esnault-Pélterie, which -had been steadily improving for eight years, had now attained great -perfection of finish, and merited prominence in actual flight. As shown -in Plate XXIX, it had a general resemblance to the _Antoinette_, though -differing throughout in its manifold details. The stream-line body was -of steel tubing, braced with wire, and tightly covered with smooth -fabric to reduce resistance. A five-cylinder R. E. P. motor in front -connected directly with the two-blade propeller. The pilot sat between -the wings with the passenger before him at the center of gravity, both -having control levers when desired for instruction. The wings could be -warped and the rudders, at the end of ample empennage planes, occupied -the extreme rear as shown. An elastically cushioned skid between the -two freely turning wheels served to absorb the shock of hard landing, -though usually not touching the ground. The R. E. P. monoplane of 1910 -was a very graceful, swift and strong machine, of marked efficiency. - -As always happens in the many-minded development of a complex -invention, the general exhibition and use of the aëroplane led toward -uniformity of design. This became particularly noticeable during the -world-wide demonstrations of 1909 and 1910. Whatever predilection the -inventor might have for his own devices, he would rather cast them -aside than lose at the tournament and in the market. Without a monopoly -of the flying art, he could ill afford to retain too affectionately -his own second-rate device in competition with a rival having a more -effective one. Accordingly there was a judicious and general adoption -of those devices which had proved best in practice, from whatever lowly -intellect they had emanated. Thus there was a marked tendency to the -general use of starting wheels, landing skids, large warping surfaces, -and, in racing machines, to the stream line concentration of the load, -and the severe elimination of resistance. - -A few examples will illustrate this tendency to choose the most -practical devices from the world’s general stock. The Wright brothers, -who, following Maxim, had been ardent votaries of the forward -horizontal rudder, discarded this in 1910 for the elastic rear -horizontal rudder introduced by Etrich. At the same time they abandoned -the antiquated catapult introduced by Langley, and adopted the -combination of wheels and skids introduced by Farman. In their racing -machine they no longer placed the aviator beside his engine, presenting -a broad front to the wind, but, like Curtiss and foreign designers, -they placed the driver and power plant in line, to diminish the -atmospheric resistance. These manifold and timely improvements indicate -clearly the advantages to mankind of an “open door” in a crescent art. - -But if the Wrights adopted the most successful devices of their -neighbors, these in turn were not slow to reciprocate that policy. -There was ample recognition of the merit of the combination of warping -sustainers and double rudder proposed by scientific men before the -advent of power aëroplanes, and so admirably employed by the Wrights -and Prof. Montgomery in their early coasting flights. The warping wing -was quite generally used on monoplanes in 1910; not to mention the -_ailerons_, which frequently were an adaptation of the same principle. - -As further illustrations, it may be noted that Voisin brothers adopted -the Farman _ailerons_ and abandoned the cellular type of sustaining -surface introduced by Hargrave, finding the vertical surfaces strongly -frictional and unnecessary for lateral equilibrium, in presence of -the _ailerons_. They also abandoned the forward horizontal rudder, -seeing that it could very well be omitted. On the other hand, it must -be observed that the Farmans, Sommer and Curtiss still retained the -combined fore and aft rudder. Curtiss and Farman also tried their hands -at monoplane construction, though without abandoning the biplane. The -most famous monoplanists, however, held firmly to their first love. -In this they were emulated by many new designers, Nieuport, Hanriot, -Déperdussin, etc. These show a marked tendency to employ smoothly -covered hulls shaped after the fish or torpedo. - -To drive the little aëroplanes so far developed, especially the -racers, there was a general preference for a single-screw propeller -mounted directly on the engine shaft, though doubtless for machines -weighing many tons a multiplicity of such propellers would be used. -Theoretically the advantage of twin screws was conceded, but in -practice they were employed by very few constructors. The Chauvière -wooden propeller was the favorite in France, and was approved by -the constructors of propellers elsewhere, at least in its general -features. The Voisin firm, indeed, still adhered to the metal -propeller, and occasionally some experimentalist employed the more -venerable French screw consisting of radial sticks covered with fabric. -But the great records in the sporting world were achieved with solid -wooden propellers. - -A special chapter would be required to describe the various motors, -even cursorily. Their relative values, however, may be summarized in -the following brief words by Réné Gasnier, in the _Aërophile_ for -November, 1910: - - “Last year we had but few light types; this year there is no - dearth of them, and at their head stands that admirable motor - _Gnome_, which has enabled aviators to accomplish all their - fine performances. At first many persons had no confidence in - the future of the rotatory motor. One must bow to the facts; - on considering the nature of this motor it is seen to be of - an admirable simplicity. It is evidently the typical aviation - motor, and an approach toward the veritable rotatory motor - which later will be the turbine. Numerous motors of four to - eight cylinders are very well spoken of, but none attain the - lightness of the _Gnome_. Among the air-cooled motors the - _Esnault-Pélterie_ is remarkable for the series of trials it - has endured, and among water-cooled motors we may cite the - splendid performance of the _Antoinette_—2,100 kilometers in - one week at the Bordeaux meeting. This would be quite a good - run even in an automobile. It is noticeable that the aëroplane - motor tends distinctly to differentiate itself from its senior, - the automobile motor, and assume a type absolutely adapted - to its special work. In addition to the greatest possible - lightness, a demand now arises for a slight consumption of - fuel, and a range of speed which is indispensable for landing. - It is dangerous to descend rapidly with the motor at full - speed; on the other hand, in cutting off the ignition to glide - down, one risks not being able to restart the motor, if need - be, while if the motor relax sufficiently the descent takes - place in perfect security. It suffices to speed up at the right - moment.” - -The practical utility of aviation began now to be questioned. The -aëroplane had passed the primary epoch of experimental development -and was becoming a standard article of manufacture representing a -considerable industry. But what was it all worth? Aviators had flown -faster than the eagle, higher than the clouds, farther than the common -distance from metropolis to metropolis. Schools were licensing new -pilots from day to day. But what career had these before them, and what -essential function in the affairs of humanity could they perform? Some, -indeed, might fit themselves for aërial service in warfare, some for -the pleasant profession of amusing and entertaining mankind; but in the -serious business of life, what important rôle could the air men hope -to play? This was the pertinent inquiry, and it was largely a question -of the reliability and economy of the aëroplane. Improvement in these -two elements might therefore receive attentive consideration in the -immediate future. - -The reliability of the aëroplane depends partly on its environment, -partly on its plan and structure, partly on the skill of its pilot. -The pilot’s skill had been admirably developed in the tournaments and -public exhibitions. The aërodynamic design conducive to stability and -steadiness, the structural design conducive to maximum strength and -resiliency, uniformly proportioned to the stress and work of each -part of the complex machine; and above all the design of the motor, -to ensure it against a thousand foibles—all these could be improved -by the patient methods of theoretical and experimental science. -The environment could, of course, be chosen. At first only the most -favorable regions need be attempted for regular transportation, regions -of level plain and farm land, or of lake and river surrounded by -country not too rough and precipitous. - -The general cost of the aëroplane to mankind depends on its plan and -structure, on the methods of manufacture, on the material running -expense; but its particular cost to the passenger is determined largely -by the cupidity or business acumen of those who furnish the machine -and those who operate it. Naturally when the world first awoke in -the morning of practical sporting aviation, with a sudden and strong -relish for flying, the prices would be fabulous, not to say ridiculous. -During that hour no commercial transportation could be contemplated. -But without monopoly the prices must quickly abate; for neither the -manufacture nor manipulation of the aëroplane demand rare ability or -training. The cost of manufacture would promptly be diminished by means -of specialized tools and operatives, immediately upon the assurance -of large and continuous orders. The cost of pilotage would become -insignificant when a single chauffeur could take a dozen passengers on -one aëroplane. - -So much for the human and external elements in the cost of aviation. -The inherent and material cost of the aëroplane could also be reduced, -though perhaps less readily. It was unlikely that the machine would -be built of much cheaper materials, or made much lighter per pound of -cargo. Nor were such improvements of so much importance since they -would affect only the first cost of the flyer. But an increase of -aërodynamic efficiency in the propeller and aëroplane proper, together -with increased thermodynamic efficiency in the motor, would materially -lower the current cost of transportation at any given speed. These -improvements would require careful research in the laboratory and -patient trial in the workshop and field. The refinement and perfection -of the aëroplane might therefore be looked for in those communities -where men have sufficient foresight, enterprise and liberality to endow -research, and to encourage the science and the art of aviation to -supplement each other. - - - - - PART III - - AËRONAUTIC METEOROLOGY - - - - - CHAPTER XIII - - GENERAL PROPERTIES OF FREE AIR - - -For aëronautic uses the atmosphere may be regarded as a mixture of two -substances, dry air and water. The first remains always in the gaseous -state; the second shifts erratically through all possible states. Rain -drops freeze or evaporate; sleet, snow, and hail evaporate or melt; -the aqueous vapor condenses or congeals. Thus the world is wrapped in -a dual sea, one part naturally serene, the other capricious, protean, -and turbulent. Dry air, indeed, is a composite of many gases of vast -concern in chemistry and biology; but in relation to aëronautics it -is practically a single permanent gas. This placid element and its -inconstant mate, so curiously mingled, constitute the medium whose flux -and vicissitudes the aërial sailor has duly to learn before he can -navigate with skill or safety.[56] - -But these aërial oceans, the moist and dry, are of very different -depth. They commingle only in the lower levels of the atmosphere, whose -qualities vary accordingly, both physical and transportational. While -the dry air may reach up to more than a hundred miles, substantial -enough to singe a meteorite, the sea of aqueous vapor is bounded -practically by the shallow region of the visible clouds. Beyond the -feather-like cirri, which just overtop the loftiest mountain peaks, -there is scant, if any, moisture. Never rain, nor cloud is there, nor -tempest nor any great perturbation. Beyond the highest excursions of -the cirri, at an elevation of some ten miles, stretches the deep ocean -of eternal sunshine, of equable and nearly constant temperature. Into -that zone of perpetual serenity no tumult of the nether atmosphere -can penetrate; against the floor of the isothermal layer the cyclonic -currents spread and dissipate. The upper air has, of course, a -considerable drift, like a majestic river or stream of the sea, but -never turmoil or tempest disturbs its stately march. - -In some respects, therefore, that lofty ocean is an ideal one for swift -transportation. But at present it is beyond the range of any navigable -craft of human invention. Occasionally, indeed, a gauzy balloon from -the hand of some inquisitive weather sage penetrates a little way into -the exalted deep next the cosmic void, bearing its delicate recorders -of heat and pressure; but it wanders alone in a silent and vast -solitude outcubing all the habitable space allotted to bird, beast -and fish; then at last sinks down to deliver the story of its strange -voyage in that lifeless outer sphere. Volcanic and celestial dust may -flourish there, tingeing the twilight with rosy flush, but no biologic -forms from the teeming underworld may find refuge or sustenance. It is -the unconquered domain of who knows what meteoric craft of the future, -sweeping the globe from continent to continent, with now unimaginable -celerity, grace and precision. - -Incidentally and aside from its aëronautic interest, the composition -of the atmosphere may be presented in fuller detail, showing the -wide variations from level to level, and the manifold complexity of -the fluid we daily breathe, not to mention the myriads of motes and -germs inhabiting every inch of it. The gaseous components and their -distribution are well exhibited in the following table,[57] which -represents an average condition: - - TABLE I - - _Percentage Distribution of Gases in the Atmosphere_ - - Key: HT = Height in Kilometers. - A = Argon. - N = Nitrogen. - WV = Water Vapor. - O = Oxygen. - CD = Carbon Dioxide. - HY = Hydrogen. - HE = Helium. - TP = Total Pressure in Millimeters. - ----+--------------------------------------------------+-------- - | GASES. | - HT +------+-------+------+------+------+-------+------+ TP - | A | N | WV | O | CD | HY | HE | - ----+------+-------+------+------+------+-------+------+-------- - 150 | | | | | | 99.73 | 0.27 | 0.0043 - 140 | | | | | | 99.70 | 0.30 | 0.0048 - 130 | | 0.02 | | | | 99.64 | 0.34 | 0.0054 - 120 | | 0.10 | | | | 99.52 | 0.38 | 0.0060 - 110 | | 0.40 | | 0.02 | | 99.16 | 0.42 | 0.0067 - 100 | | 1.63 | | 0.07 | | 97.84 | 0.46 | 0.0076 - 90 | | 6.57 | | 0.32 | | 92.62 | 0.49 | 0.0090 - 80 | | 22.70 | | 1.38 | | 75.47 | 0.45 | 0.0123 - 70 | 0.02 | 53.73 | | 4.0 | | 41.95 | 0.27 | 0.0248 - 60 | 0.04 | 78.16 | | 7.32 | | 14.33 | 0.15 | 0.0810 - 50 | 0.08 | 86.16 | |10.01 | | 3.72 | 0.03 | 0.466 - 40 | 0.16 | 86.51 | |12.45 | | 0.88 | | 1.65 - 30 | 0.22 | 84.48 | |15.10 | | 0.20 | | 8.04 - 20 | 0.55 | 81.34 | |18.05 | 0.01 | 0.05 | | 39.6 - 15 | 0.74 | 79.56 | |19.66 | 0.02 | 0.02 | | 88.2 - 11 | 0.94 | 78.02 | 0.01 |20.99 | 0.03 | 0.01 | |168 - 5 | 0.94 | 77.89 | 0.18 |20.95 | 0.03 | 0.01 | |405 - 0 | 0.93 | 77.08 | 1.20 |20.75 | 0.03 | 0.01 | |760 - ----+------+-------+------+------+------+-------+------+-------- - -Fixing attention first upon the gases other than water, it will be -at once observed from the table that these gases show a very uniform -mixture in the moist and turbulent region, while farther aloft the -lighter of them tend to predominate in relative proportion. This -uniformity of composition at the lower levels, which accords with -experience, is due to the constant circulation and turmoil in that -region. But for this constant agitation, the uniformity of mixture -could not last. If the atmosphere were perpetually at rest throughout, -or moving only in horizontal flow, each constituent gas would assume -the same status and distribution as if the others were absent. Each, -therefore, obeying Dalton’s law of diffusion, would form an atmosphere -of itself, independent of the others, and unaffected in density by -them. Such a condition is assumed for the higher levels. The percentage -distribution in the higher levels is calculated from the known -elasticity and density of the gases, assumed as resting in perpetual -calm at a constant temperature of .55° C. beyond eleven kilometers, or -above the highest ascent of man, and, furthermore, as having at the -earth’s surface 1.2 per cent moisture and a temperature of 11° C. - -But only in the quiescent outersphere can that dynamic gradation be -established or perpetuated. Below this lofty region is the sea of -water vapor, mingled intimately with the dry air, and churned with -it, yet not sharing its uniformity of distribution. Why this rapid -diminution of moisture with elevation, as shown in the table? Because -throughout the moist region the temperature falls rapidly—about 6° C. -per kilometer ascent above the earth—thus chilling and precipitating -the vapor, whose pressural resistance to liquefaction diminishes with -waning temperature. The explanation is obvious; but why does it not -apply as well to the other elements of the atmosphere: why do not the -other gases present liquefy with falling temperature as well as the -water vapor, which is merely water in the gaseous state? The question -cannot be answered very profoundly, but an essential condition of -liquefaction of any gas can be stated in learned phraseology, after the -preliminary exposition of certain general properties of matter. - -We may first set forth those general physical properties, then apply -them to answering the above question. Every known substance may exist -in either of three states, the solid, liquid or gaseous. For every -substance there is a critical temperature above which it can exist -only as a gas, and cannot be liquefied by any pressure, but below -which a suitable pressure will cause liquefaction. Below its critical -temperature a gas is called a vapor, above it a permanent gas. Now in -the free atmosphere some of the gases are never below their critical -temperatures and, therefore, cannot be liquefied by any pressure, -without special cooling; others are sometimes below their critical -temperatures and are then capable of liquefaction by sufficient -pressure, which however is not always found in free space, but can be -supplied by a compression pump; one other gas, that is water vapor, -is always below its critical temperature in the free atmosphere, and -therefore may always be turned into water by sufficient pressure at its -actual atmospheric temperature. Such sufficient pressure in the water -vapor actually occurs from time to time in all parts of the atmosphere -from the earth’s surface to the highest cirrus region, but more -frequently in the nimbus levels, a mile or two above the earth. Thus -at all parts of the lower atmosphere liquefaction of aqueous vapor is -sometimes observed, either as mist or rain, snow or ice particles, and -on the earth as dew or frost. In order to illustrate the above ideas -by numerical citation, the accompanying table is given, showing the -critical temperature and pressure of the chief gaseous constituents of -the atmosphere. - - TABLE II - - _Critical Temperature and Corresponding Pressure of Liquefaction for - the Chief Constituent Gases of the Atmosphere._ - - --------------+-------------+------------- - | Critical | Critical - Substance | Temperature | Pressure - | C. | Atmospheres. - --------------+-------------+------------- - Dry Air | -140 | 39 - Nitrogen | -146 | 34 - Oxygen | -118 | 50 - Carbonic Acid | - 31 | 75 - Argon | -120 | 51 - Hydrogen | -242 | 20 - Ammonia | 130 | 115 - Water | +365 | 200 - --------------+-------------+------------- - -A glance at this table shows that for the pressures and temperatures -prevailing in our atmosphere most of the constituents are permanent -gases. The conspicuous exception is water which, when in the gaseous -state, always exists as a vapor, and never as a permanent gas, since -it never even approaches the critical temperature. Fortunately for all -life on earth the aqueous vapor condenses at very ordinary temperatures -and pressures, else there would be no rainfall for irrigation and -drinking. Fortunately also the other gases do not so precipitate, else -the world might be flooded with liquid nitrogen and oxygen, entailing -who knows what disastrous consequences. - -After this digression on the composition of the atmosphere, we may -henceforth regard the aërial ocean as a mixture of two substances, -dry air and water; the first, a permanent gas; the second, a -variable element, existing at times in either the solid, liquid, or -vaporous state. For the sake of convenience we may first study the -dry atmosphere, then the moist. The dynamic properties of the dry -atmosphere may in large measure be deduced by an application of two -well-established laws of physics. These will be taken in order. - -By careful investigation it has been proved that throughout a -considerable range of pressure and temperature the permanent gases -very approximately obey the following law; the volume of a permanent -gas varies directly as its absolute temperature and inversely as its -pressure. In other words the product of its pressure and volume equals -the absolute temperature multiplied by a numerical constant. This may -be expressed algebraically by the following formula: - - _PV_ = _RT_ (1) - -in which _P_ is the pressure and _V_ the volume of a given portion of -gas at the absolute temperature _T_, and _R_ is a numerical constant -for the gas in question. - -The value of _R_ in the foregoing equation has been determined -experimentally for the component gases of the atmosphere, and for dry -air as a whole. For dry air, which, under such conditions as surround -the aëronaut, may be treated as a single uniform gas, the equation -applied to one kilogram gives R = _PoVo/To_ = 29.27, where _Po_, _Vo_, -_To_, are respectively the pressure, volume and temperature, in the -metric system, of the one kilogram of air under standard conditions; -i. e., _Po_ = 10,330 kilograms per square meter, being the normal -atmospheric pressure; _Vo_ = 1/1.293 cubic meter, being the volume of -one kilogram of dry air at normal pressure and freezing temperature; -_To_ = 273° C., being the absolute temperature of freezing. In passing, -be it said that the absolute temperature is that measured from the -absolute zero, which on the Centigrade scale is 273° below freezing, on -the Fahrenheit, 460.6° below freezing. - -The second law referred to follows directly from the principle of the -permanence of mass. It is a general observation in physics that a given -portion of matter is of constant mass, however its pressure, volume, -temperature and other conditions may vary. In particular, the mass of a -given portion of matter always equals the product of its mean density -and volume, since density is defined as the amount of mass in the unit -volume. Expressing this physical law, or relation algebraically, gives -ρ_V_ = mass = ρ_o_, _Vo_, in which ρ, _V_, are the general symbols -for the density and volume of the given portion of matter under any -condition, while ρ_o_, _Vo_, are the specific values of ρ and _V_ -observed for some one state and circumstance of the substance in -question. In particular, if the mass of air be unity, we may write: - - ρ_V_ = 1 (2) - -This relation, together with that expressed in equation (1), will -enable us to deduce many of the properties of dry air and of a dry -atmosphere. - -First let us observe from equation (1) the effect, in turn, of keeping -constant one of the quantities _P_, _V_, _T_, while the other two vary. -The equation shows that if the temperature of a gas is kept constant -the volume is inversely proportional to the temperature. This is called -the law of Boyle and Mariotte from its two independent discoverers, -of whom Boyle seems to have been the first. As an example of Boyle’s -law, if any empty glass, or diving bell, be inverted over water, -then submerged deeper and deeper, the air within it will shrink with -increase of pressure, its volume becoming one half when the pressure is -doubled, one third when the pressure is trebled, etc. In particular, if -the pressure changes by one unit, the corresponding change of volume -is 1/_P_ part of that volume. For example, if a captive balloon is -anchored in air at constant temperature, while the barometric pressure -changes from 30.0 inches to 30.1 inches, the volume of the balloon -will contract 1/300 part of itself. - -Again equation (1) shows that if the pressure of a gas is kept -constant, the volume is proportional to the absolute temperature. This -is the law of Charles and Gay Lussac, so called from its discoverers, -of whom Charles is thought to have been the first. As an example of -this law, if a captive thin rubber balloon is heated, or cooled, its -volume will vary directly as its absolute temperature. In particular, -if the temperature is changed one degree, the volume changes 1/_T_ -part of itself. For example, if the temperature of a balloon in air of -constant barometric pressure is heated from 300° C. to 301° C., its -volume will expand 1/300 part of itself. Historically, be it said, this -law of Charles and the law of Boyle were discovered separately, then -combined, giving equation (1). - -Still a third, though not independent relation may be read from -equation (1), thus: when the volume of a gas is kept constant, the -pressure is proportional to the absolute temperature. In particular, if -the temperature is changed one degree, the pressure varies accordingly -by 1/_T_ part of itself. For example, if an air tank or gas tank, in a -room at 500° F., changes one degree in temperature, its pressure will -change 1/500 part. - -With minute detail these three conclusions from the general equation -(1) have been set forth and illustrated, because of their practical -importance. Other valuable results may be obtained by similar -reasoning. Thus equation (2) may be read; the volume of a unit mass of -any substance is the reciprocal of its density. Hence, if in the three -foregoing conclusions, the reciprocal of the density is everywhere -written for the volume, three new relations will be obtained which -are of frequent practical use. Two of them may be expressed in the -following important law; the density of a gas varies directly as its -pressure and inversely as its temperature. Useful applications of this -law in aëronautics suggest themselves at once. - -By means of the various foregoing equations, the value of either one -of the four quantities _P_, _V_, _T_, ρ, representing respectively -the pressure, volume, absolute temperature, and the density, may be -obtained in terms of any two of the others. If then any two of the -quantities is observed, the others can be at once computed. If, for -example, the pressure and temperature of dry air be observed at any -point, its density can be computed from the formulæ, also its volume -per kilogram weight, and thence its volume for any other weight. It is -important therefore to be able to measure satisfactorily at least two -of the four quantities. In usual studies of the atmosphere the pressure -and temperature are observed directly. The method and instruments -employed for that purpose are too well known to require description -here. - -In some speculations the pressure and temperature of the atmosphere -are assumed, and certain interesting conclusions drawn. For instance, -if the temperature is assumed constant throughout a dry atmosphere, -the fluid will obey Boyle’s law, and it can be easily shown that the -height of such a medium is the same whether it comprise much gas or -little.[58] Again assuming the temperature and pressure constant, the -height of the normal homogeneous atmosphere can be computed by dividing -the pressure per square unit by its weight per cubic unit. In this way -the height of the normal homogeneous atmosphere has been found to be -about five miles. But these are hypothetical cases, of purely theoretic -interest. In practice the temperature may, on the average, be assumed -to decrease 6° C. for each kilometer of ascent, and the pressures may -then be computed for various elevations by use of Boyle’s law, as done -for Table I. - -This leads us to a study of the gaseous properties of moist air. By -moist air is meant a mixture of dry air and aqueous vapor in the form -of an invisible elastic gas. The definition does not comprise air -containing visible steam, or mist, or cloud, but clear moist air such -as one ordinarily breathes. The study of this mixture may be preceded -by a brief account of the gaseous properties of the vapor alone. - -If water in sufficiently small quantity be introduced in a vacuum -bottle at any ordinary temperature, it will promptly evaporate, -forming an invisible gas known as aqueous vapor, filling the bottle -and exerting a uniform pressure on its walls, except for the minute -difference at top and bottom due to gravity. The vapor weighs 0.622 as -much as dry air having the same volume, temperature and pressure, or -quite accurately ⅝ as much. It obeys all the laws given above for -ordinary gases and dry air. But it has one singularity; at ordinary -atmospheric temperatures, it cannot be indefinitely compressed -without condensing to a liquid. In this respect it differs from the -chief components of the atmosphere, which at ordinary temperatures -can endure indefinite pressure without liquefaction. The ammonia and -carbon dioxide in the air can, it is true, be condensed by pressure at -their usual temperatures, but not by such pressures as occur in the -free atmosphere, thus still leaving aqueous vapor the one singular -constituent. - -Reverting to the behavior of the water in the assumed vacuum -bottle at fixed temperature, it may be observed that the pressure -of the invisible vapor is directly proportional to the amount of -liquid evaporated. In other words, for any fixed temperature the -vapor pressure is directly proportional to its density. When this -density reaches a certain definite amount, dependent solely upon the -temperature, no further evaporation will occur, unless some of the -vapor condenses. The pressure of saturation for that temperature has -been reached, and any attempt to increase the pressure, by diminishing -the volume of the vapor, will cause liquefaction at constant -temperature. - -If, however, the space is not saturated, the mass of vapor present may -be expressed as a percentage of the amount required for saturation at -that temperature. This percentage is called the relative humidity. Thus -if the relative humidity is seventy per cent, the actual mass of water -vapor present at the observed temperature is seventy per cent of the -maximum that can exist in the given space, at the given temperature. In -other words, the relative humidity is the ratio of the actual to the -possible humidity at a given temperature. - -In like manner, for any given vapor pressure there is a definite -saturation temperature, known as the dew-point. If with constant -pressure the vapor is given various temperatures higher than the -dew-point, it will remain gaseous and invisible; but if it falls in -temperature to the dew-point, liquefaction occurs, and drops of water -appear on the inner wall of the vessel. Further cooling will entail -still further liquefaction and reduction of pressure; for the lower -the temperature the less the possible mass and pressure of saturation. -But for all temperatures, down to freezing and considerably below, -some vapor exists, and obeys the same laws as at higher temperatures. -When, however, saturation occurs below freezing, the vapor may be -precipitated as snow instead of water. This is a familiar phenomenon -in the free atmosphere. - -The actual mass of water vapor present in a cubic unit of space -is sometimes called the absolute humidity. A formula giving the -absolute humidity _f_, in kilograms per cubic meter, for any observed -temperature _t_, and vapor pressure _e_, may be written as follows: - - _f_ = 0.00106 _e_ / (1 + 0.00367 _t_) - -in which _e_ is the vapor pressure in millimeters of mercury, and _t_ -is the common Centigrade reading. As an illustration of the actual -values of the pressure, temperature and density of saturated water -vapor, for various conditions, the following table is presented: - - - TABLE III - - _Temperature, Pressure and Density of Aqueous Vapor, in Metric - Measures._ - - -------------+--------------+----------------- - Temperature, | Pressure, | Density Kilos. - Centigrade. | Millimeters. | per cubic meter. - -------------+--------------+----------------- - -25 | 0.61 | .557 - -20 | 0.94 | .892 - -15 | 1.44 | 1.395 - -10 | 2.15 | 2.154 - - 5 | 3.16 | 3.244 - 0 | 4.57 | 4.835 - + 5 | 6.51 | 6.761 - 10 | 9.14 | 9.329 - 15 | 12.67 | 12.712 - 20 | 17.36 | 17.117 - 25 | 23.52 | 22.795 - 30 | 31.51 | 30.036 - 35 | 41.78 | 39.183 - 40 | 54.87 | - 45 | 71.36 | - -------------+--------------+----------------- - -Now by Dalton’s law, each gas or vapor in a mixture of several behaves -as if it were alone. Thus if the foregoing experiment be conducted in -a bottle containing various gases chemically inert to water, the same -mass of water will be evaporated, and exert the same uniform pressure, -in addition to those exerted by the gases. Now the density of each -gas or vapor present, will equal its mass divided by its volume, and -the density of the mixture will equal the total mass divided by the -volume. Furthermore, it is well known that aqueous vapor is less dense -than dry air at the same temperature and pressure. From this it is at -once evident that moist air, which is merely a mixture of dry air and -aqueous vapor, must be lighter than dry air at the same temperature and -pressure. This is true whether the two fluids compared be in closed -vessels or in the free atmosphere. - -Accordingly in all precise dealing with the free air, whether involving -its buoyancy, its resistance, its energy or any other mass function, -its density as affected by the humidity must be taken into account. -This can be computed from the observed pressure, temperature and -relative humidity as revealed by well known instruments, the barometer, -thermometer and hygrometer. Thus from the observed temperature and -relative humidity, the mass of vapor present per cubic meter is read -from Table III, the reader, of course, multiplying the given tabulated -mass by the observed percentage of humidity. To this aqueous mass must -be added the mass of dry air present. Then the total mass per cubic -meter is the density. - -Various formulæ are available for computing the density of moist -air from the readings of the three instruments mentioned above. -Also, tables have been worked out giving the density without further -calculation. Moreover, the density of free air may be directly -measured, accurately enough for most purposes, by means of a -densimeter. A simple formula for finding the density of moist air is -as follows: - - ρ = 0.465(_b − e_)/_T_ - -in which _b_, _e_, are the pressures in millimeters mercury -respectively of the moist air and its vapor, as revealed by the -barometer and hygrometer. - -In practice no great error will be made in assuming the relative -humidity to be fifty per cent. For the moisture content never exceeds -five per cent of the mass of the moist air, and hence in assuming a -fifty per cent relative humidity, when there is actually a maximum -or minimum humidity, the greatest possible error in estimating the -moisture content is 2.5 per cent of the mass of moist air. Now if 2.5 -per cent of a mass of air be assumed to be aqueous vapor when all is -really dry air, or conversely if 2.5 per cent of the whole mass be -assumed as dry air when it is really aqueous vapor, an error of much -less than 2.5 per cent is made in estimating the true density. No error -at all would ensue if both air and vapor were of the same density; but -since one is ⅝ as heavy as the other, the possible error is ⅜ of -2.5 per cent, or 0.6 per cent. This is a negligible quantity in all -mechanical considerations, except where great accuracy is required. - -When any gas changes density or volume it also changes temperature, -unless there be transfer of heat between it and its environment. When -change of volume occurs without such transfer of heat the expansion, -or contraction, is called “adiabatic;” when it occurs at constant -temperature, the expansion is called “isothermal,” the temperature -being kept uniform by suitable transfer of heat; when it occurs at -constant pressure it is called “isopiestic.” In either case work may -be done by the enlarging gas, if it press against a moving piston, -or yielding envelope of some kind; and conversely work may be spent -on the gas in compressing it either isothermally, adiabatically or -isopiestically. - -If, for example, a balloon rises rapidly its contents will expand -adiabatically, pushing the envelope out in all directions against the -static pressure of the embracing atmosphere. Thus it will do work and -rapidly cool. But if it rapidly sinks, it will contract adiabatically -and grow warm, owing to the work done by the surrounding air in -compressing it. A like thing occurs when a great volume of air rises -or sinks quickly in the free atmosphere. In this case the change of -temperature is about 6° C. for each kilometer change of level, so long -as the air remains unsaturated. A familiar example of this effect in -Nature is manifested when an uprushing column of moist air chills, and -precipitates moisture, forming a cloud toward its top. Thus a lone -thundercloud in a clear sky may mark the upper part of such a column, -or upward vortex in the air. And contrarywise, a descending column may -absorb its visible moisture, causing it to become clear aqueous vapor, -and thus vanish from view. - - - - - CHAPTER XIV - - GENERAL DISTRIBUTION OF HEAT AND PRESSURE - - -Having thus briefly examined the composition and certain gaseous -properties of free air, both dry and moist, we may now study the -atmosphere as a whole. We wish particularly to know of its distribution -of temperature and pressure; of its general and permanent circulation; -of its great periodic currents; of its vertical movements, and its -minor local winds with their pulsations of velocity and direction. -Fortunately much information is available, due both to governmental -and private research, though this was collected more for purposes of -meteorology than of aërial locomotion. Of late, however, attention has -been given to the aëronautic study of the atmosphere, which will, it is -hoped, prove valuable to the aërial navigator. - -The movements of the atmosphere are due mainly to the sun’s heat and -to the rotation of the earth. The earth’s internal heat and the moon’s -attraction are other minor agencies, but these may be neglected by -comparison. The earth’s rotation also would be ineffectual in modifying -the aërial movements, except for the coöperation of the sun. Without -his influence the atmosphere, always stagnant, would simply rotate with -the globe, at constant angular velocity and uniformly graded density at -various levels. This evenness of density for any level is broken by the -solar radiation increasing the temperature and moisture, otherwise the -air would remain practically at a standstill. - -Though the moisture by its lesser density causes some lightening of -the air at fixed temperature, this at most is hardly one per cent, as -already shown, and on the average is much less. Its effect, therefore, -is equivalent to less than that caused by a rise of temperature of -three degrees. But if precipitation occurs, an enormous amount of -stored sunshine, or latent heat, is liberated and applied to warming -the associated air. Thus each pound of vapor condensed may, by the -release of its thermal store, heat more than a ton of air one degree -in temperature, or more than half a ton of air two degrees, etc. -The actual number of pounds of air at constant pressure, raised one -degree Centigrade by the condensation of one pound of vapor at various -temperatures, is given in the following table: - - TABLE IV - - --------------------------------+-------+-------+------- - Temperature of condensation | 0° | 25° | 50° - Pounds of air heated one degree | 2550 | 2480 | 2407 - --------------------------------+-------+-------+------- - -The sun then is father of the wind. By uneven heating of the atmosphere -it disturbs the uniform density gradation that would otherwise exist. -Thus abnormal pressures are generated which disturb the repose of the -aërial sea, causing the fluid to flow from regions of excessive to -regions of defective pressure. Hence the study of insolation[59] and -temperature distribution is fundamental to the science of the winds. - -Without detailed study, we may note the aggregate insolation received -by the earth, at various latitudes, and its general effect on -terrestrial temperature. The sun emits a nearly constant stream of -radiation, from year to year, which plays continuously upon the earth -as a whole, with an intensity which varies but slightly from month to -month, due to the slightly varying distances of the earth from the -sun. Owing to the sun’s seasonal wandering across the equator, the -insolation at any latitude varies considerably month by month, and -the polar regions receive much more light than if no such wandering -occurred. The total yearly insolation for every 5° of latitude is shown -in the following table from Hann, in which the unit is the amount that -the earth would receive in one day at the time of the equinox, if the -sun were at its mean distance from the earth: - - TABLE V - - _Annual Amounts of Insolation_ - - -----------+---------+------------ - Latitude. | Thermal | Difference. - | Days. | - -----------+---------+------------ - 0° | 350.3 | - 5° | 349.1 | 1.2 - 10° | 345.5 | 3.6 - 15° | 339.4 | 6.1 - 20° | 331.2 | 8.2 - 25° | 320.5 | 10.7 - 30° | 307.9 | 12.6 - 35° | 293.2 | 14.7 - 40° | 276.8 | 16.4 - 45° | 258.7 | 18.1 - 50° | 239.6 | 19.1 - 55° | 219.4 | 20.2 - 60° | 199.2 | 20.2 - 65° | 180.2 | 19.0 - 70° | 166.2 | 14.0 - 75° | 156.5 | 9.7 - 80° | 150.2 | 6.3 - 85° | 146.5 | 3.7 - 90° | 145.4 | 1.1 - -----------+---------+------------ - -From this it appears that the equator receives nearly 2.5 times as much -heat yearly as the poles. Since, moreover, the equator enjoys nearly -constant insolation, while the polar regions suffer great variations of -heat, with the varying altitude of the sun, the equatorial atmosphere -is both much hotter and more equable than the poles, and high latitudes -generally. Thus at the equator the frost level stands constantly -at 18,000 feet, while in the middle latitudes it varies greatly in -height from season to season. If, for example, a circle be drawn to -represent the earth, and above it a line to indicate the mean altitude -of the frost level in July, the frost line starting at the equator -at an elevation of 18,000 feet will decline north and south, finally -touching the earth well toward the frigid zones. The levels for other -temperatures, above and below freezing, are similarly inclined downward -from the equator to north and south. Obviously these isothermal -levels vary with the varying season, and at any fixed time differ on -different longitudes. On the plane of any given latitude the frost -line varies much less in altitude, and so for the other isothermals. -This is particularly true at the poles and equator, and everywhere at -considerable altitude. If one voyaged around the earth at the equator -at an elevation of 5,000 feet, he should find the average temperature -about 65° F. In the temperate zone, following a line of latitude -at the same height, he should have a lower temperature, but still -comparatively equable. The average annual temperature of the earth’s -entire surface is about 60° F. - -In practical meteorology the temperature is observed at many points -simultaneously over a wide stretch of the earth’s surface. These -are then plotted on a weather chart, and through all points of like -temperature are drawn lines known as isothermals. These lines not only -map the earth’s surface into regions of equal temperature, but they -also show the direction of fall or rise of temperature, and its space -rate of change. This rate is called the “temperature gradient,” and -when estimated straight across from isothermal to isothermal, that is -in the direction of liveliest change of temperature, it is the maximum -gradient. Such a map is very useful in forecasting the weather. It is -but a particular instance of the more general map conceived by the -physicist, exhibiting the thermal condition of the entire atmosphere by -means of a series of equal temperature surfaces one above the other. -Here, of course, the temperature gradient at any point is the space -rate of change of temperature in any direction, being zero along the -isothermal surface and greatest normal to it. - -The vertical temperature gradient is of particular interest, since -it determines the condition of fluid equilibrium at any point in the -atmosphere when the level surfaces are isothermal. If, for example, a -balanced balloon or portion of air, on starting upward from any level, -cools faster than the environing stagnant air, it will become more -dense, and cease to ascend, in which case the atmospheric equilibrium -is stable. Again, if the ascending gas or air cools more slowly than -the surrounding medium, it will become less dense, and so continue -to ascend, in which case the atmospheric equilibrium at the point -is unstable. Thirdly, if the rate of cooling be identical for the -ascending gas and its surrounding medium, the equilibrium is neutral, -and the motion will be stopped by friction but unaffected by change -of buoyancy, since no such change can occur. Of these three states of -equilibrium, the stable is dominant above the cirrus level, while below -that level each state may be found, at various times, prevailing at -random in all parts of the world, but more generally the stable and -neutral states. When the unstable condition occurs at any locality and -any level, it is usually followed ere long by a commotion or upheaval -in the atmosphere, until the temperature gradient alters to the neutral -or stable. - -Many observations have been made to determine the variation of -temperature along the verticle in various places and in different -seasons. From the temperature records obtained in 722 balloon -ascensions near Paris, France, the mean fall of temperature per 1000 -feet up to 20,000 feet was found to be 2°.4 in winter, 2°.8 in spring, -2°.6 in summer, 2°.5 in autumn and 2°.6 for the year. Near Berlin 3°.1 -for the year was found from 75 balloon ascensions, the rate being -nearly the same for the halves of the year. Fig. 44 gives the average -of 52 winter and 65 summer temperature gradients, taken at about 8 A.M. -by means of sounding balloons sent up at Munich, Strassburg, Trappe and -Uccle. It will be noted that in both summer and winter the temperature -falls rapidly with increase of elevation, up to ten or eleven -kilometers, but above twelve remains nearly constant for all altitudes. -The difference in temperature summer and winter is interesting, also in -its gradual diminution with altitude. Another striking feature is the -inversion of gradient shown at twelve kilometers elevation, where the -temperature ceases to diminish, and may even increase with altitude. -This region is known as the upper inversion level of the atmosphere, as -distinguished from other levels at or below three kilometers height, -known as lower inversions, where the temperature gradient is sometimes -reversed, though not so illustrated in the diagram. - -Thus the atmosphere divides into three marked layers. The lower -layer, three kilometers deep, is the region of turbulence and storm, -the home of heavy rain clouds, lightning, wind gusts and irregular -temperatures. The middle layer, some seven kilometers thick, bounded -top and bottom by the upper and lower inversion levels, is a clear -region of steady-falling temperature, for the most part frigid—a region -of far reaching and rapid winds, sweeping eastwardly, except near the -equator, and bearing on their backs the frosty cirrus clouds. The upper -layer reaching from the cirri to the cosmic void, is always cloudless -and very frigid, with temperature nearly constant, or maybe slightly -increasing with elevation. - -[Illustration: FIG. 44.—SUMMER AND WINTER AVERAGE VERTICAL TEMPERATURE -GRADIENTS.] - -A striking peculiarity of these three regions is that the lower and -middle layers may freely intermingle with each other, but never with -the upper, or isothermal layer. Owing to its constant temperature, the -upper layer floats on its neighbor like oil on water.[60] If a mass of -dry air were forced up into it from below, with the natural cooling due -to adiabatic expansion, such mass would be denser than the surrounding -medium, and hence would promptly sink back to its initial position. -Thus whatever turmoil may vex the middle or lower region, it can at -most upheave the floor of the isothermal layer, leaving inviolate the -crystal depths of the empyrean. - -We may now turn to the distribution of barometric pressure in -the atmosphere and the effect of its variation. In general, the -distribution is not very uniform, but it can be graphically pictured by -drawing a series of surfaces connecting all points of equal pressure. -These are called isobaric surfaces. In a stagnant uniformly heated -atmosphere, for example, these surfaces would lie one above the other -parallel to the ocean face; but where turmoil exists, and irregular -temperature distribution, the isobaric surfaces are bent into hills -and hollows of varied form. These surfaces not only map the aërial sea -into regions of equal pressure, but they also show the direction of -fall or rise of pressure, and its space rate of change. This rate is -called the “pressure gradient.” When estimated straight across from -surface to surface, that is, in the direction of the liveliest change -of pressure, it is the maximum pressure gradient. Along this normal -direction the air tends to flow with an acceleration proportional to -the gradient. The velocity thus acquired by any portion of air in -being pushed along the line of falling pressure, combined with its -velocity due to other causes, gives its true velocity. A most important -consideration, therefore, in a scientific study of the wind is the -pressure distribution. - -In practical meteorology, observations of the barometric pressure are -made simultaneously at many points on the earth’s surface, and the -readings then plotted on a map, after “reduction to sea level.” This -reduction is made by adding to each barometric reading the weight of a -column of air between the barometer level and the sea level, according -to tables prepared for this purpose. Lines called “isobars”[61] are -then drawn, at regular intervals, through all points of like sea-level -pressure, the indicated change of pressure between consecutive isobars -on the U. S. weather map being usually one-tenth of an inch of mercury. -These exhibit at once, over the entire field of observation, the -horizontal pressure gradient reduced to sea level, and commonly called -the “barometric gradient.” In meteorology, the pressure normal to the -isobar is called the gradient, and is expressed in millimeters of -mercury per degree of a great circle. On the same weather chart are -mapped the isothermal lines and wind directions for all the stations -of the weather service. From these data and the reported moisture -conditions, the meteorologist forecasts the probable weather some hours -or days in advance. - -No perfectly comprehensive formula can be given for the barometric -pressure at any place and altitude, but certain general laws may be -observed. Where, for example, the speed of the air is increased along -any level of an air stream, the pressure is lessened, and conversely. -Thus, if the wind blows squarely against the front of an isolated -house, the speed will be greatly checked at the center front, and -accelerated at both sides and over the roof, thereby increasing the -apparent barometric pressure on the front, and lessening it on the -sides and over the top. A similar effect may be observed when the air -flows round the hull and framing of air craft. - -Again, if the atmosphere over any locality is heated appreciably more -than its environment, the heated column tends to expand upward and -overflow aloft in all directions toward the cooler neighborhood, thus -lessening the pressure throughout the heated column, and increasing -the pressure throughout the environing atmosphere laterally. When this -effect is marked the plotted isobars often form a series of closed -curves about the heated region, manifesting a pressure gradient at the -lower levels in all directions toward the heated area. This grouping of -the isobars exhibits the familiar low pressure area of the weather map. -On the other hand, if any locality be cooled appreciably more than its -environment, the cooled column sinks, so that the surrounding warmer -air aloft flows in over it, thereby increasing the pressure over the -cooled area, and diminishing it throughout the environment. The isobars -may then form a series of closed curves about the cooled region, with a -pressure gradient along the higher levels in all directions away from -the cooled area. Of course, if heat were the only agency disturbing -the earth’s barometric pressure, there should be a parallelism between -the heat and pressure gradients; but, as already noted, the speed -or momentum of the aërial currents is also a substantial agency in -modifying the pressure lines. - -It is well to remember that, while the base of a warm column of air -may, due to the overflow aloft, have less pressure than the base of -the cool environing column which receives the overflow, the high part -of the column may have greater pressure than the equally high part of -the cool. For if the columns be initially of the same temperature and -pressure, heating one of them uplifts its levels of given pressure -above those of its neighbor. When the overflow begins, a partial -equalization of pressure levels occurs, but not a complete one so long -as the flow has any head. - -An interesting hygrometric feature of these highs and lows may here -be observed in passing. As already explained, when a column of air -ascends it cools by expansion, and tends to precipitate its water -content as cloud or rain; and conversely, when the air sinks it heats -by compression, thus acquiring greater moisture capacity and tending -to clarify. As a consequence, the areas of low pressure and a rising -atmosphere are usually marked by clouds and rainfall, while the areas -of high pressure and falling atmosphere are marked by clear, or -clearing weather. In the low, damp areas, then, the air feels heavy -while it is really light; in the high and dry area the air feels light, -while it is really dense, and most favorable to air men for carrying -heavy loads in their balloons or flyers. Similarly when air flows over -a mountain range the ascending stream precipitates moisture, due to -cooling by expansion, while the descending stream, on the other side, -comes down hot and dry, due to compression. - -A characteristic mechanical feature of the high and low pressure areas -is the closed circulation between them, involving practically the whole -atmosphere below the isothermal layer. If we conceive the entire globe -spotted with high and low areas, we may picture the air surging upward -in the lows, flowing outward under the isothermal layer, descending in -the highs, then flowing outward along the earth’s surface toward the -lows in a continuous cycle. Thus, chiefly is maintained the vast and -multifold circulation of the atmosphere over the entire world. - -In general the motion is of a vortical nature, by which is meant that -the masses of air as they flow along stream suffer more or less change -of orientation in space, the rotation at times being so slight as to -be undetectable, and again so marked as to excite wonder, as in the -whirlwind. Many of these atmospheric vortices, even though varying -in diameter from a few yards to hundreds of miles, resemble in their -behavior the gyrating column of water in a common circular basin -emptying through an orifice at its bottom. If the water is very still -when the drain opens, the column descends with imperceptible, if any, -rotation; but if the column has an initial whirl, or angular velocity, -this is magnified as the water approaches the axis of the vortex, -the tendency of the mass being to preserve its angular momentum, or -fly wheel property. A like action obtains in the great atmospheric -vortices, though here the motion far from the axis may seem like a -straight-blowing wind, rather than part of a vast whirl covering -thousands of square miles. - -But even if all the air started directly for the axis of the ascending -column, like still water in a basin, it would promptly acquire vortex -motion, because it flows on the surface of a rotating sphere. The -deflection so produced is evidently greatest at the poles, and for -other places equals the polar value multiplied by the sine of the -latitude. The effect is similar to what occurs when a basin, rotating -about a vertical axis and carrying water with the same angular -velocity, is opened at the bottom. In this case the water at once -begins to gyrate within the basin, as the particles move toward its -axis. - -With these preliminary generalities we may proceed to study the more -prominent movements in the atmosphere. - - - - - CHAPTER XV - - PERMANENT AND PERIODIC WINDS - - -The winds of the world are commonly classified as the permanent, the -periodic and the nonperiodic, according to their genesis and character. -Their chief features may be briefly outlined. - -The most conspicuous and important aërial current on the globe is -the permanent double vortex playing between the equator and the -poles. The heated air of the equatorial belt, uplifted by expansion, -overflows beneath the isothermal layer toward the north and south, -thereby increasing the pressure in the higher latitudes sufficiently -to generate a surface inflow along the earth, and thus maintaining a -perpetual closed circulation which is felt all over the globe. The -main features of this motion have been determined mathematically by -Ferrel,[62] and summarized as follows: - - “In the preceding part of this chapter it has been shown that, - if all parts of the atmosphere had the same temperature, there - would be a complete calm over all parts of the earth’s surface. - But that, in consequence of the difference of temperature - between the equatorial and polar regions of the globe, and - the consequent temperature gradient, there arise pressure - gradients and forces which give rise to and maintain a vertical - circulation of the atmosphere, with a motion of the air of - the upper strata of the atmosphere from the equator toward - the poles, and a counter current in the lower part from the - poles toward the equator, as represented by the arrows in the - following figure, and that this of course requires a gradual - settling down of the air from the higher to the lower strata in - the middle and higher latitudes and the reverse in the lower - latitudes. It has also been shown that in case the earth had - no rotation on its axis, this would be exclusively a vertical - circulation in the planes of the meridians without any east or - west components of motion in any part; but that, in consequence - of the deflecting forces arising from the earth’s rotation, the - atmosphere at the earth’s surface has also an east component - of motion in the middle and higher latitudes, and the reverse - in the lower latitudes, and that the velocities of the east - components increase with increase of elevation, so that at - great altitudes they become very much greater than those - at the earth’s surface; while those of the west components - decrease with increase of altitude up to a certain altitude, - where they vanish and change signs and become east velocities, - now increasing with increase of altitude to the top of the - atmosphere. - - “It has been further shown that the deflecting forces arising - from the east components of motion of each hemisphere from the - earth’s surface to the top of the atmosphere, in the middle - and higher latitudes and of the upper part of the atmosphere - in the lower latitudes, drives the atmosphere from the polar - regions toward the equator, while those arising from the west - components of motion in the lower part of the atmosphere in - the lower latitudes, having a contrary effect, but small in - comparison with the other on account of the weakness of these - forces near the equator, tend to drive the air a little from - the equator toward the poles. There is, therefore, a depression - of the isobaric surfaces at all altitudes in the polar - regions, especially in the southern hemisphere, a much smaller - depression in the equatorial regions, and a bulging up of the - isobaric surfaces in the vicinity of the parallel of 30° in - the lower part of the atmosphere, the maximum being nearer the - equator as the altitude increases, as represented in Fig. 45, - but at high altitudes there is a minimum of barometric pressure - at the poles and a maximum at the equator. - -[Illustration: FIG. 45.—GENERAL CIRCULATION OF THE ATMOSPHERE.] - - “In the accompanying figure the solid arrows in the interior - part represent the resultant motions of the winds (longer - arrows indicating greater velocities), in case of an earth - with a homogeneous surface over both hemispheres, in which - the motions would be symmetrical in both and the same at all - longitudes, and the equatorial and tropical calm belts would - be situated at equal distances from each pole. The dotted - arrows indicate the strong, almost eastern motion of the air - at all latitudes at some high altitude, as that of the cirrus - clouds. - - “The outline of the outer part of the figure represents an - isobaric surface high up where the bulging up near the parallel - of 30° disappears and the maximum pressure at the same altitude - is transferred to the equator. For lower altitudes the isobaric - surfaces have a bulging up at the parallel of 30°, and a slight - depression at and near the equator. The arrows in this part - represent the polar and equatorial components of motion, the - former above and the latter below, except near the earth’s - surface on the polar sides of the tropical calm-belts, where - there is a polar component of motion arising from the air’s - being pressed out from under the belt of high pressure. This, - perhaps, does not extend beyond the polar circles, beyond - which there can be little motion in any direction, except from - abnormal disturbances. - - “For reasons given in §103, the actual mean position of the - equatorial and tropical calm-belts are not precisely as here - represented, but are all a little displaced toward the north - pole, and the polar depression of the isobaric surfaces is - greater in the southern than in the northern hemisphere.” - -The conclusions from this approximate analysis are in the main -supported by observation, except as modified by the heterogeneity -of the earth’s surface. The sea-level distribution of barometric -pressure between the equator and poles, as found by Ross’ long series -of measurements, manifests a variation of about one inch of mercury, -with maxima at about 30° of latitude, north and south, as required -by Ferrel’s theory. As a further cause of the depression toward the -poles, may be mentioned the greater speed of the permanent east wind -with the consequent centrifugal lift in the atmosphere. - -As to the general easterly direction of the winds at middle and -higher latitudes, that is well known from observation of the motion -of clouds and of the air near the earth. At the cirrus level the -velocity in those latitudes is almost exactly eastward. But the flow -in longitude, illustrated by the outer arrows in Fig. 45, has not -been fully determined by observation. Moreover, as Ferrel himself -showed, the unequal heating of continents and oceans sets up gradients -in longitude, especially in the northern hemisphere, thus adding -considerable disturbance to the general circulation. To this agency -must be added also the latitudinal shifting of insolation, due to the -annual march of the sun across the equator, entailing an oscillatory -seasonal shift of the hot belt, and therefore of the twin-hemispheric -cycle of the atmosphere. - -Some currents of the general and permanent circulation are sufficiently -prominent to have special names, such as the _trade-winds_, the -_antitrade-winds_, the _prevailing westerlies_, and, in the lower -latitudes, the _calm belts_, where the flow is exceptionally feeble. -All these currents have been known to sailors since early times, and -have been of considerable importance in marine navigation. Eventually, -perhaps, they may be of like importance in aërial navigation. - -The trade-winds are mild tropical surface currents of remarkably steady -speed and direction. Springing from the high-pressure belts in either -hemisphere, at about latitude 30°, they blow toward the equator with -increasing westerly trend. As shown in charts 46 and 47 for midwinter -and midsummer, the trade winds cover a large portion of the tropical -zones in both oceans, and shift slightly in latitude with the sun. -They are separated at the heat equator by the equatorial calm belts, or -doldrums, and are bounded north and south respectively by the calms of -Cancer and of Capricorn. Particularly interesting are the trade-winds -blowing from Spain to the West Indies, which favored Columbus on his -westward voyage, and which certain adventurous Germans have proposed -using to duplicate that memorable voyage, in air ships. - -[Illustration: FIG. 46.—NORMAL WIND DIRECTION AND VELOCITY FOR JANUARY -AND FEBRUARY. (KÖPPEN.)] - -The antitrade-winds, or counter trades, are lofty winds blowing over -and contrary to the trade winds. As some doubt regarding the direction -of these counter trades had existed, an expedition was sent in 1905, by -two distinguished meteorologists, Teisserenc de Bort of France, and A. -Lawrence Rotch of America, to explore the atmosphere above the tropical -Atlantic. Mr. Rotch has summarized their measurements and conclusions -as follows:[63] - - “Pilot balloons, dispatched from the island of Teneriffe and - St. Vincent, were observed with theodolites at the ends of a - base-line, and in this way the heights at which the balloons - changed direction could be ascertained. Later the balloons - were sent up from the yacht itself, which steamed after them, - measurements being made of their angular elevation. The - observations which are plotted in Fig. 46 prove conclusively - the existence of the upper counter-trade. The courses of - the balloons are represented as if projected upon the - surface of the sea and show that the northeast trade-wind - extended only to the height of 3,200 or 4,000 meters, and - then gradually turned into a southerly current which, higher - up, came from the southwest. The width of the dotted band - represents approximately the varying velocity of the trade and - counter-trade. Similar proofs of the northwest trade-wind, - south of the equator were obtained by the same expedition - during the following year, but the above suffices to show that - it would be possible for an aëronaut in the ordinary balloon - to start from the African coast, or from some of the islands - in the trade-wind region, and, after drifting towards the - southwest, to rise a few miles into the current, which would - carry the balloon north and eventually northeast back to land. - Nevertheless, it does happen in certain atmospheric situations - over the tropical north Atlantic that the winds from the - general northwesterly direction prevail up to great heights - without any evidence of the return-trade. Near the equator the - winds are easterly up to the greatest heights which have been - attained.” - -[Illustration: FIG. 47.—NORMAL WIND DIRECTION AND VELOCITY FOR JULY AND -AUGUST. (KÖPPEN.)] - -[Illustration: FIG. 48.—TRADE AND COUNTER TRADE-WINDS.] - -The prevailing westerlies are high-latitude surface winds of the -permanent circulation. In the southern hemisphere they are particularly -strong and steady owing to the comparatively unbroken stretch of -ocean. In the north also they are strong and persistent, but variable -in direction because of disturbances by local winds due to unequal -heating of tracts of land and sea. These features are well illustrated -in charts 47 and 48. Of particular interest in aëronautics is the -prevailing wind blowing from the United States to Europe, which has -been considered a suitable current for transoceanic balloon voyages.[64] - -The periodic winds are those whose gradient alternates annually or -daily, due to annual or daily fluctuations of temperature on sloping -or on heterogeneous parts of the globe. The annually fluctuating winds -due to alternate heating and cooling of continents, or large land -areas, bear the general name of monsoon. Among diurnal winds the most -prominent are the land-and-sea breezes, and the mountain-and-valley -breezes. Both kinds are practically available in aëronautics; the -monsoons for long-distance travel, the diurnal winds for local use. - -The general motive cause is the same for all periodic winds. When any -portion of the earth’s surface is periodically more heated above its -normal temperature, or average for the year, than the neighboring -region, the resulting abnormal temperature gradient causes a periodic -surface wind tending toward the excessively heated place, and a counter -wind above. That is, the cooler and heavier column of air sinking and -uplifting the lighter, results in a lowering of the common center of -gravity of the two columns of air, and thus furnishes the driving -power of the wind. For example, an island or a peninsula may be -considerably hotter by day and cooler by night than the surrounding -water; a continent may be much hotter in summer and much colder in -winter than the bordering ocean. Thus during the hot period a moist -wind blows landward; during the cold period a dry wind blows seaward. -If the land has vast and lofty slopes the uprush of air during the hot -period and the downrush during the cool period may be very powerful. -The currents so produced by the aggregate of local agencies, including -the deviation caused by the earth’s rotation, combine with the general -circulation of the atmosphere to form the actual wind of the place. -Thus the periodic current may conspire with the general circulation, -or oppose it; may intensify, weaken or obliterate it; may overmaster, -reverse or mask it completely. - -Of the various continental monsoons of the globe the most powerful -spring from the annual flux and reflux of the atmosphere over the vast -declivities and table-lands of Asia. Here the conditions are especially -favorable. As the sun approaches Cancer, the burning deserts and high -plateaus, combining their force with the draft on the mountain sides, -generate a continental uprush that sucks in all the aërial currents of -the surrounding seas, hurling them aloft to the isothermal layer whence -they radiate as the four winds of heaven; for here at this season the -planetary circulation is disrupted, obliterated or reversed, appearing -merely as a perturbation of the monsoon at its height. In India the -force is particularly effective. Along the north the Himalayas stretch -1,300 miles in latitude, with an average height of 18,000 feet and -with sunburned areas on either side. North of this range are the lofty -plateaus of Thibet and Cashmere, south of it the desert of Gobi and -the borders of the Indian Ocean. Over this watery tract from beyond the -equatorial line, from the isles of Oceanica and from the wintry plains -of Australia, the air flows in with accumulated strength, sweeping the -Bay of Bengal and the Arabian Sea in a continuous gale bearing up the -mountain slopes incredible floods of water. Over the Arabian Sea in -summer the gale is so steady and swift that no ordinary ship can force -a passage from Bombay to the Gulf of Aden. Above the Bay of Bengal the -moist south winds, converging between the coast and headlands, pour -cloud laden up the Himalayan slopes, precipitating their whole vapor -in prodigious torrents seldom seen elsewhere. Khasia at this season -sustains a Noachian deluge, the rain at times falling nearly a yard -deep in one day and night.[65] Quite appropriately, therefore, the -summer monsoon over India, especially its component southwest wind from -the Arabian Sea, and southerly wind from the Bengal Bay and farther -east, is called the wet monsoon. - -The winter monsoon of Asia, is the reverse of the summer one, both -in direction of gradient and in physical character. It is a cold -flood of air pouring from the frigid table-lands and wintry depths -of the desert, down the mountains and valleys in continual overflow -on all sides of the continent, and then far out over the sea, where -it reascends to complete its long cycle. In its descent all moisture -vanishes by heating, and no intensive temperature gradient occurs, as -in summer, to accelerate its gently modulated tide. In India the winds -from Cashmere and Thibet pour down the Himalayas toward the Arabian Sea -a clear current of air which unites with the trade-wind, increasing -its force, and forming the moderate winter monsoon of that region, or -as it is commonly called, from its lack of moisture, the dry monsoon. - -The kinematic character, and the extent of both summer and winter -currents, are well portrayed in charts 47 and 48 for all the south and -southeast of Asia. Across the islands of Japan, it will be observed, -the winds blow in opposite directions summer and winter. In Siberia -the monsoon winds trend along her great rivers and valleys, generally -northward in the winter and the reverse in the summer, combining in -both seasons with the prevailing westerlies, due to the rotation of the -earth. - -All the other continents have their monsoons, though less powerful -than those of Asia. In the great desert of Sahara, for example, there -is an ascending hot current in the summer, causing a strong indraught -from the Atlantic and the Mediterranean; but this is far less intense -than if its action were fortified by lofty slopes and table-lands. In -winter when the Sahara cools to nearly the oceanic temperature, little -monsoon effect is perceptible, and the general circulation continues -unperturbed. In Australia the monsoon influence is still feebler, -owing to the limited extent of the country and to the general lowness -and flatness of the land. Over parts of South America, the annual -ebb and flow of the atmosphere is considerable, particularly along -the northeastern coast, and in the whole Amazon Valley, whose aërial -currents in general conspire with the trade-winds, strengthening them -materially in the southern summer, though it is less in winter when the -continental temperature more nearly approximates that of the ocean. The -monsoons of North America have been described in some detail by Ferrel -as follows: - - “On the continent of North America we have monsoon influences - similar to those of Asia, but not nearly so strong, because - the extent of the continent, and consequently the annual range - of temperature, are not so great. They are, for the most part, - not sufficiently strong to completely overcome and reverse the - current of the general circulation of the atmosphere, and so - to produce a real monsoon, but they cause great differences - between the prevailing directions of the winter and summer - winds. - - “In the summer the whole interior of the continent becomes - heated up to a temperature much above that of the oceans on the - same latitudes on each side—indeed, above that of the Gulf of - Mexico and the Pacific Ocean on its southern and southwestern - borders. The consequence is that the air over the interior of - the continent becomes more rare than over the oceans, rises - up and flows out in all directions above while the barometric - pressure is diminished, and the air from all sides, from the - Atlantic on the east to Pacific Ocean on the west, the Gulf of - Mexico on the south, and the polar sea on the north, flows in - below to supply its place. On the east the tendency to flow in - is not strong enough to counteract the general easterly motion - of the air at the earth’s surface in the middle latitudes, and - to cause a westerly current, but it simply retards the general - easterly current and gives rise to a greater prevalence of - easterly winds along the Atlantic sea-coast during the summer - season.... - - “In winter the thermal conditions over the continent are - reversed. The interior of the continent is now the coldest - part, and it is especially colder than the surrounding oceans - at that season. It has also very high plateaus and mountain - ranges. The air, therefore, of the lower strata, and especially - those next the earth’s surface, now tends to flow out in all - directions to the warmer oceans and the Gulf of Mexico, and - especially to run down the long slope of plateau from the - Rocky Mountains into the Mississippi Valley. The effect over - the whole of the United States east of the Rocky Mountains - is to cause the winds, which otherwise would be westerly and - southwesterly, to become generally northwesterly winds, instead - of southerly and southwesterly ones, as in summer. There is not - a complete monsoon effect, but simply a great change between - summer and winter in the prevailing directions of the winds. In - Texas, however, and farther east along the northern border of - the Gulf, the effect is somewhat that of a complete monsoon. In - New England and farther south in the Eastern States the monsoon - effect is to cause the prevailing winds to be from some point - north of west, instead of south of west as in summer. - - “In summer, Central America and Mexico have a much higher - temperature than that of the adjacent tropical sea on the - southwest, and having high mountain ranges and elevated - plateaus, there is consequently a strong tendency to draw in - air from the southwest at this season, which not only entirely - counteracts the regular trade-winds of these latitudes, but - even reverses them and causes southwest winds. The effect is to - cause in midsummer a large area here, extending far westward, - of calms and irregular and light winds, mostly southwesterly - ones, and an apparent widening of the equatorial calm-belt at - this season so as to make its northern limit reach up, along - the coast, nearly to the parallel of 20°. The effect is similar - to that in the Atlantic west of the Gulf of Guinea and Liberia, - except that it here appears to be some greater, and causes - a true monsoon effect, since during the winter the regular - northeasterly trade-winds prevail, but strengthened by the - reverse thermal conditions of the winter season. On the eastern - side, and over the western end of the Gulf of Mexico, there is - a somewhat regular monsoon effect, the prevailing winds being - easterly, or blowing toward the land, during the summer, and - the reverse in winter. - - “Along the west coast of North America in the middle latitudes - there is a strong monsoon influence; for the interior of the - continent becomes heated in summer to a much higher temperature - than that of the southwesterly ocean, and hence a strong - current is drawn in from this direction, at right angles to - the general trend of the coast which, combining with the - general southwesterly winds of these latitudes in the general - circulation of the atmosphere, causes the strong and steady - westerly and southwesterly winds of this region during the - summer. Farther north, up toward Alaska, the summer monsoon - effect is combined with the current caused by the deflection - of the continent as well as the general easterly current of - high latitudes, so that the winds here are generally southerly, - but still have somewhat of a monsoon character, being southerly - and southwesterly in summer and easterly and southeasterly - during the winter. - - “Along the northern coast of America, as along that of Siberia, - the monsoon tendency is to draw the air from the colder land - to the warmer ocean in winter, and the reverse in summer; and - these effects, combined with the general easterly motion of - the atmosphere in these latitudes, gives rise to prevailing - southwesterly winds in winter and northwesterly ones in summer. - The winter monsoon influence, however, is small here—much - more so than in Siberia, for the ocean contains so many large - islands that it has rather a continental than an oceanic winter - temperature; and besides, it has not the influence of a warm - current—such as the continuation of a part of the Gulf Stream - along the northern coast of Europe and Asia.” - -Similar to the monsoons in essential nature are the diurnal winds of -seacoast and mountain side. They begin with the heating of the land -in the morning, attain their maximum intensity about mid afternoon, -or during the hottest of the day, and finally are reversed at night. -Besides being so much briefer than monsoons, they are also in general -feebler and less extensive. They may be quite noticeable on calm -days, especially in clear weather and in hot climates; but usually -they are masked or entirely overwhelmed where other marked currents -occur—currents due either to the general circulation or monsoons, or -other powerful disturbing agencies. - -In land-and-sea breezes, which usually extend not far inland, there is -a surface inflow of sea air during the forenoon and early afternoon, -balanced by an outflow of warm air above, rising from the heated soil. -After sundown this is reversed, the chilled air from inland pouring -out to sea, while overhead the warmer sea air is forced landward at a -higher level. These currents are strongest where the diurnal range of -temperature is greatest and where the local topography is of suitable -configuration. Particularly favorable are steeply declining shores, -narrow bays and inlets, girded by mountains or lofty hills. During -the day heated air ascends such declivities with alacrity, like smoke -through an inclined flue, while at night, when cooled by radiation -and contact with the soil, it rushes torrentlike down the valleys and -hillsides, passing out to sea, often in sudden squalls that embarrass, -or endanger, small sailing craft. Circulatory currents like the above -have sometimes been used by aëronauts to carry them out to sea and back -again to land at a different level. - -In like manner the mountain-and-valley winds may be used by the -skillful aëronaut. It is well known that these flow up the courses of -rivers, cañons and land slopes generally by day, but at night reverse -their course and pour down again with considerable force. For this -reason experienced hunters place their camp fires below tent in a -sloping valley. The strength of the breeze depends, of course, upon -the daily range of temperature, and the steepness and expanse of the -slope. Such winds are deftly used by the masters of soaring flight, the -great robber and scavenger birds, and no doubt may be used by men in -motorless aëroplanes, to gain elevation, and journey great distances -without expenditure of energy. - - - - - CHAPTER XVI - - CYCLONES, TORNADOES, WATERSPOUTS - - -Besides the periodic winds so far treated, there are prominent aërial -movements having no regular course or season. These are the nonperiodic -winds which so exercise or perplex the weather forecaster and those who -confide in him. In general such winds are of a temporary character, -arising from an unstable condition of the air in some locality, or -from unequal heating, either of which causes may generate, or briefly -sustain, an updraught, with its attendant gyration. Owing to the -whirling character of such ascending currents, they have received -various significant names, such as cyclone, tornado, whirlwind; the -three terms applying to vortices in decreasing order of magnitude. Each -in turn may be treated briefly. - -The cyclone is a temporary large gyratory wind. It may last a few hours -or a few days. It may measure fifty to a hundred miles across, or it -may measure more than a thousand miles. On the weather map it is in -general marked by a group of closed isobars, showing a considerable -pressure gradient toward a small internal area where the pressure is -a minimum. To an observer looking about the earth’s surface and lower -levels of the atmosphere, the cyclone appears merely as an ordinary -wind, accompanied perhaps by rain or snow. It is not a swiftly rotating -narrow column, or cone of air, like a tornado or whirlwind, full of -gyrating dust and débris. - -The motive power of a cyclone, though in general due to the buoyancy -of heated air, may spring from more than one set of conditions. Notice -has already been taken of vortices due to a hot column of air at lower -barometric pressure than its lateral environment. Take another case. -If a dry atmosphere is of uniform temperature and pressure at various -levels, but has a vertical temperature gradient a little greater than -the normal cooling of an ascending gas, a portion of air started upward -in any casual way becomes warmer than its lateral environment, and -hence continues to rise until the unstable condition due to abnormal -temperature gradient ceases. Again, while the surface stratum is in -stable equilibrium, it may happen that the second mile of air is -abnormally hot, and the third mile abnormally cold, and thus a vortex -may occur in mid air, without disturbing the face of the earth. - -Whatever be the initial atmospheric condition causing the vertical -uprush, the nature of the resulting circulation is in general that of -the cyclone, illustrated, in part, by the whirling vortex of water in -a basin. As the current ascends, an indraught occurs in all the lower -regions of air, and an outflow in all directions above, sometimes -at the height of a mile or two, again in all the region next to the -isothermal layer. As the earth has at all places above the equator -a component of rotation about the vertical line, it follows that in -northern latitudes all the air flowing toward the vortex is in a whirl -opposite in motion to the hands of a watch lying face upward, and all -the outflowing air above has a like angular motion, but gradually -diminishing until it is reversed. At the lower portion of the vortex -the air whirls inward and upward with increasing velocity, while -above, it whirls outward and upward, with waning velocity, thus moving -in a double-spiral path shaped like a cord wound on an hourglass. In -the constricted part, or neutral plane of the vortex, the air moves -neither outward nor inward, but spirals straight upward. To match the -upflow, and complete the closed circulation, there must be a downflow -on the exterior of the cyclone, and since the whirl is reversed -in direction, this outer mass of downflowing reverse-whirling air -embracing the cyclone is called the anticyclone. - -Between the inner and outer vortex the air is comparatively calm and -the pressure is a maximum, with steepest gradient toward the center -of the cyclone. Also the air is calm just at the axis of the vortex, -while for some distance away its speed increases as the radius of its -whirl, so that the central mass rotates practically as a solid column, -thus still further lowering the pressure near the axis. This solidly -rotating central column of air is sometimes called the core of the -vortex. - -High above the center of the cyclone, where perhaps the air is sucked -downward, clarified by compression, then whirled outward, the sky is -usually clear, or thinly fogged, while without this central patch are -heavy clouds. The obscure or clear central part is called the “eye[66] -of the storm.” Through this the cirrus clouds may sometimes be seen -high above, either stationary or radiating away, if the vortex extends -so high. Sailors on the deck of a vessel passing through a cyclone have -often noticed the eye of the storm overhead, perhaps ten or twelve -degrees in diameter, and with special clearness in the tropics. To the -white, feathery cirrus clouds, scurrying away radially from the top of -the vortex, they have given the name “plumes of the storm,” or “mares’ -tails.” In sailing their vessel through the center of a cyclone, they -have observed the circulatory motion of the winds and clouds, and -frequently have found the deck covered or surrounded with cyclone -sweepings, such as land and water birds, insects, butterflies, etc., -brought into the quiet core of the vortex from the incurving winds -beyond. Further details of the motion in a cyclone vortex are given as -follows by Ferrel, §178: - - “In Fig. 49 is given a graphic representation of the resultant - motions and of the barometric pressures for both the surface - of the earth and for some level high up in the atmosphere and - above the neutral plane, where the motions in the vertical - circulation are outward from the center. The solid circles - represent isobars at the earth’s surface and the solid arrows - the directions, and in some measure, by their different - lengths, the relative velocities of the wind. The heavy circle - represents the circle of greatest barometric pressure at the - earth’s surface, say 765 mm., while the pressure of the outer - border is 760 mm., and the dividing line between the cyclone - and the anticyclonic gyrations. Within this limit the pressure - diminishes to the center, and the gyrations are cyclonic, and - the direction of the resultant of motion inclines in toward the - center, but beyond that limit the gyrations are anticyclonic, - and the direction of resultant motion inclines toward the outer - border of these gyrations. The heavy dotted circle represents - the circle of maximum pressure at some high level, and is much - nearer the center than that at the earth’s surface. It is - also the dividing line between the cyclonic and anticyclonic - gyrations at that level. The dotted arrows indicate the - directions and in some measure the relative velocities, of the - wind at this level. The arrows in the cyclonic part represent - the direction of the wind as declining outward, because the - plane here considered is supposed to be above the neutral - plane, where the radial component of motion is outward, but - for any level below the neutral plane the inclination is still - inward. The arrows are shorter above in the cyclonic part and - longer in the anticyclonic part than they are at the earth’s - surface, since the cyclonic gyratory velocities decrease and - the anticyclonic increase with increase of altitude. - -[Illustration: FIG. 49.—VELOCITY DIAGRAM IN HORIZONTAL SECTION OF A -CYCLONE.] - - “The upper part of the figure is a representation of a vertical - section of the air, very much exaggerated in altitude, in - which the solid curved line represents a section of an isobaric - surface near the earth’s surface, say of 740 mm. barometric - pressure. The lowest part corresponds with the center of the - cyclone and the highest part with the heavy circle in the - lower part of the figure, and the steepest gradients with the - longest solid arrows, since the greater the gyratory velocities - at the earth’s surface the greater the gradients, though they - are not strictly proportional. The second dotted curved line - from the top represents a section of the isobaric surface of - high altitudes, in which the highest parts correspond with - the heavy dotted circle below, since the highest pressure at - all altitudes is very nearly where the cyclonic gyrations - vanish and change to the anti-cyclonic. The depression here - is smaller because the cyclonic area is smaller, and the - gyratory velocities less, than at the earth’s surface. The - upper dotted line belongs to an isobaric surface still higher, - where the gyrations are supposed to be all anti-cyclonic, and - here, consequently, the greatest pressure is in the center, as - indicated by the curved line. - - “As the interior of the whole cyclonic system is warmer - than the exterior, and consequently the air less dense, the - distances between the isobaric surfaces are necessarily greater - in the interior than the exterior part, and so, however much - the isobaric surface at or near the earth’s surface may be - depressed by the cyclone gyration there, at a considerable - altitude, if the temperature difference is great enough, it - must become convex instead of concave. - - “The track of any given particle of air in a cyclone, resulting - from the vertical and gyratory circulation, is that of a - large converging and ascending spiral in the lower part, but - of a diverging and ascending spiral in the upper strata of - the atmosphere, and the nearer the earth’s surface the more - nearly horizontal is the motion, since the vertical component - gradually decreases and vanishes at the surface. - - “The whole energy of the system by which the inertia of the - air and the frictional resistance are overcome and the motions - maintained, is in the greater interior temperature and the - temperature gradients, by which the circulation is maintained. - This being kept up, the deflections and gyrations are merely - the result of the modifying influence of the earth’s rotation, - which is not a real force, since it does not give rise to - kinetic energy, but merely to changes of direction. - - “It must be borne in mind that the preceding is a - representation of the motions and pressures of a cyclone - resulting from perfectly regular conditions, in an atmosphere - otherwise undisturbed, and having a uniform temperature, - except so far as it is affected by the temperature disturbance - arising from the cyclonic conditions. Accordingly results so - regular are not to be found in Nature, but generally only rough - approximations to them. - - “Since the wind inclines less and less toward the center of the - cyclone below the neutral plane and declines from the center - above it, the upper currents above this plane in a cyclone are - always from a direction, in the northern hemisphere, a little - to the right of that of the lower currents, when not affected - by abnormal circumstances.” - -Observation of cyclones in Nature very well confirms the leading -features set forth on theoretical grounds. If the vortex pass centrally -over an observatory there is noted first a high barometer and calm air, -attended perhaps by scurrying cirrus clouds; next a rapidly falling -pressure and increasing wind, with dark clouds and precipitation, -commonly accompanied by thunder and lightning; then the hushing of -the storm to a dead calm, and low barometer and thinning or clearing -of the clouds overhead; then a rising barometer with renewed winds in -the reverse direction, and finally subsiding winds, rising barometer -and clearing weather. These phenomena are the more definitely presented -if the whirl is strong while its travel along the earth is slow. But -owing to their progressive easterly motions, cyclones in the north have -their moist hot southern masses elevated, chilled and precipitated -on their eastern fronts and beyond, while their rear experiences the -opposite action and is called the clearing side. Conversely in the -tropics the westerly moving cyclones have cloudy and wet rears, because -the easterly drift on high carries the precipitating masses toward the -rear. The general hygrometric appearance of a centrally passing cyclone -in middle latitude is thus described by Ferrel, §207: - - “In the regular progression of a cyclone in the middle - latitudes somewhat centrally over a place, the cloud and rain - area of the front part, extending far toward the east, first - passes over, occupying a half-day, or a day and more, and - then the front part of the ring of dense cloud with a heavy - shower of rainfall. After this there are indications of a - clearing up, and even the sun may break through the cloud for - an hour or two; but presently there is an apparent gathering - and thickening of the cloud and a second shower. This is at - the time of the passage of the rear side of the ring of denser - cloud. After this there is the final clearing up.” - -Except for special conditions, cyclones are never stationary, but drift -along with the general march of the atmosphere, like dimpling eddies in -a stately flowing river. In general, therefore, their trend is westward -in lower latitudes, eastward in middle and higher latitudes, with a -pace slow or swift according to the prevailing current. Notably also -they have a poleward trend. Thus, if the path extends from tropic to -temperate clime, it is frequently concave toward the east and sensibly -parabolic in form. This is markedly true of those swift-whirling, small -cyclones called hurricanes,[67] and particularly those vigorous ones -blowing past the West Indies and the Philippines, and those that vex -the Indian Ocean. - -As to the speed of travel of cyclones, that may be judged, at least for -northern latitudes, from the accompanying table, taken from Loomis,[68] -and showing the average monthly rate of progression in miles per hour, -of cyclone centers over the United States, the Atlantic Ocean and -Europe. In general, beyond the tropics tall cyclones travel faster than -short ones, owing to the faster drift of the higher strata. - - ----------+----------+--------------+--------- - | | Atlantic | - | United | Ocean Middle | Europe. - Month. | States. | Latitudes. | - ----------+----------+--------------+--------- - January | 33.8 | 17.4 | 17.4 - February | 34.2 | 19.5 | 18.0 - March | 31.5 | 19.7 | 17.5 - April | 27.5 | 19.4 | 16.2 - May | 25.5 | 16.6 | 14.7 - June | 24.4 | 17.5 | 15.8 - July | 24.6 | 15.8 | 14.2 - August | 22.6 | 16.3 | 14.0 - September | 24.7 | 17.2 | 17.3 - October | 27.6 | 18.7 | 19.0 - November | 29.9 | 20.0 | 18.6 - December | 33.4 | 18.3 | 17.9 - ----------+----------+--------------+--------- - Year | 28.4 | 18.0 | 16.7 - ----------+----------+--------------+--------- - -To find the actual speed of the wind at a place, of course, the linear -velocities of whirl and of translation must be combined; or, vice -versa, if one of these be known it can be graphically subtracted from -the observed wind velocity to find the other. This combination of two -wind components to find their resultant, or, vice versa, can easily be -done by laying off on paper, arrows of suitable length and direction -to represent the two known velocities, placing the head of one arrow -to the tail of the other, then completing the triangle, and taking its -third side to represent the required wind velocity, in magnitude and -direction. Obviously if the cyclone moves eastward, whirling oppositely -to the hands of a watch, the swiftest wind is on its right side, -which consequently is known as the dangerous side. In the northern -hemisphere, therefore, the rule for dodging a great whirlwind is to run -north, if that be practicable. - -Stationary cyclones occur under favorable conditions. At least that -name has been applied to columns of hot air streaming up from a fixed -base, more or less circular. Every island in the ocean generates such -a vortex on a clear, hot summer day, since its temperature far exceeds -that of the surrounding water. All day long this uprush continues -whatever be the humidity. And if the soil slopes upward steeply, the -vortex is so much the stronger, particularly if the island be in a calm -region. Above such a tract the gulls and vultures, and possibly even -man, might soar all day without motive power. This condition and its -interesting possibility deserve investigation. - -Cyclones may occur at any season, but in general they are most abundant -when the greatest temperature disturbances occur. The relative -frequency of tropical cyclones for various localities and for the -twelve months of the year is seen in the following table[69]: - - _The Yearly Periods of Cyclone Frequency in Several Seas_ - - ------------+---------+---------+----------+----------+-------+------- - | Arabian | Bay of | S. Indian| Java | China | - | Sea. | Bengal. | Ocean. | Sea. | Sea. |Havana. - ------------+---------+---------+----------+----------+-------+------- - No. of years| 234 | 139 | 40 | -- | 85 | 363 - No. of | | | | | | - cyclones | 70 | 115 | 53 | 12 | 214 | 355 - | | |Piddington|Piddington| - Authority. |Chambers.|Blanford.|Thom and |and |Schuck.| Poey. - | | |Reid. |Thom. | | - ------------+---------+---------+----------+----------+-------+------- - Jan | 6 | 2 | 17 | 25 | 2 | 1 - Feb | 4 | 0 | 25 | 42 | 0 | 2 - Mar | 3 | 2 | 19 | 8 | 2 | 3 - April | 13 | 8 | 15 | 8 | 2 | 3 - May | 18 | 16 | 7 | 0 | 5 | 1 - June | 29 | 9 | 0 | 0 | 5 | 3 - July | 3 | 3 | 0 | 0 | 10 | 12 - Aug | 3 | 4 | 0 | 0 | 19 | 27 - Sept | 4 | 5 | 2 | 0 | 27 | 23 - Oct | 6 | 27 | 2 | 0 | 16 | 17 - Nov | 14 | 16 | 7 | 0 | 8 | 5 - Dec | 3 | 8 | 6 | 17 | 3 | 2 - ------------+---------+---------+----------+----------+-------+------- - -The tornado is a slender cyclone or hurricane. It is usually but a -few yards or rods in diameter, and seldom exceeds one mile across its -active column, whereas a cyclone may cover an area of any size from -fifty to one or two thousand miles in diameter. Moreover, the cyclone -requires for its inception an extensive pressure gradient marked by -closed isobars, and once generated may last several days. A tornado per -contra may spring into action where the lateral pressure is uniform, -spend its force in a few moments, and leave a uniform barometric field -in its wake. In shape the tornado is usually of greater height than -width. The cyclone is far-flung laterally, but in height may not exceed -the narrow tornado, since both must terminate beneath the isothermal -layer, and commonly do not extend so high. Both vortices are caused -by the ascensional force of hot air. In both the air spirals in and -upward at the bottom, out and upward at the top, constantly cooling -by expansion, and finally descends on the outside to complete the -closed circulation. In general the tornado is the more violent and -destructive, though limited to a brief and narrow path. More aptly, -perhaps, the tornado may be called a slender hurricane of brief -duration; both of them being small cyclones, or aërial vortices, of -minor size and concentrated intensity. The relation of the tornado and -cyclone has been defined as follows, by Professor Moore: - - “The cyclone is a horizontally revolving disk of air of - probably 1,000 miles in diameter, while the tornado is a - revolving mass of air of only about 1,000 yards in diameter, - and is simply an incident of the cyclone, nearly always - occurring in its southeast quadrant. The cyclone may cause - moderate or high winds through a vast expanse of territory, - while the tornado, with a vortical motion almost unmeasurable, - always leaves a trail of destruction in an area infinitesimal - in comparison with the area covered by the cyclone.” - -Two initial conditions seem essential to the genesis of a substantial -tornado. In the first place, the atmosphere of its immediate locality -must have appreciable gyration. Of course, in all extra equatorial -regions the air has some incipient whirl due to the earth’s rotation, -and this whirl is magnified as the fluid is sucked into the vortex. But -the magnification may be slight owing to the brief lateral displacement -of the air feeding the tornado. If, however, the fluid be drawn from a -considerable distance, and have from local conditions some additional -whirl superadded to that due to the earth’s rotation, the gyratory -flow in the medium near the vortical axis may be very swift. On the -other hand, the additional whirl, due to local conditions, may tend -to neutralize that due to the earth’s component, thereby leaving a -very feeble gyration, if any. But in general the rotation of tornadoes -is observed to be in the direction of the earth’s component; to the -left north of the equator, to the right south of it. This observation -is doubtless the more striking because when the accidental local spin -conspires with the permanent terrestrial one, the resultant whirl -is intensified, while in the opposite case it is so enfeebled as to -attract scant, if any attention. - -In the second place, the genesis of a tornado requires unstable -equilibrium in the local atmosphere. This instability, as in cyclones, -may arise from abnormal temperature gradation. Thus, if along any -vertical the temperature falls more than six degrees Centigrade for one -thousand meters ascent, a mass of air started upward will continue to -rise, since it cools less rapidly than the environing medium. In this -way there will ensue a continuous uprush of air so long as the unstable -state endures; and the action may be very vigorous if a large stratum -of air is greatly heated before it disrupts into the cold upper layers. -In general, the loftier the tornado the more violent it is, just as -the taller flue generates the stronger draft with the same temperature -gradient. - -Dynamically, the tornado may be treated as a rotating pillar of air -in which each mass of fluid fairly retains its angular momentum. This -means that for any mass of the whirling air the radius of its path, -multiplied by its circular speed, remains a constant product; in -other words, the velocity of whirl varies inversely as the radius. -Accordingly, the circular velocity is exceedingly rapid where the -radius is very small. Now, when any mass runs round a circle its -centrifugal force is known to be directly as the square of the speed of -its centroid and inversely as the radius. But by the above assumption -the speed itself is inversely as the radius. Hence, the centrifugal -force varies inversely as the cube of the radius of the inflowing -mass of air. This centrifugal force, acting on the inner layers of -air of the rotating column, must be supported by the pressure against -them exerted by the outer layers as they pass inward. Thus there is a -strong barometric gradient from the remote still air toward the swiftly -whirling parts of the vortex. - -It follows from the above argument that inside a tornado the barometric -pressure may be much below the normal; and it is easy to see that if -a barometer, starting from some point on the tornado base, be moved -vertically upward it must show a declining pressure, but if moved -upward and outward it may be made to show a constant pressure all the -way to the upper portion of the vortex. The instrument would thus -travel along an isobaric, bell-shaped surface opening upward. On a -series, therefore, of concentric circles on the base of a tornado, -we may erect a family of coaxial bell-shaped surfaces to mark the -points of equal pressure, and thus map out the isobars of the vortex. -Inside these coaxial surfaces reaching to earth, others of still -lower pressure may be drawn tapering downward to a rounded point and -terminating at various places on the axis. In an actual tornado one of -these infinitely numerous funnel-shaped isobaric surfaces may become -distinctly outlined and visible, if the air has sufficient moisture to -start precipitation when it reaches a surface of suitably low pressure. -This quite usually occurs in Nature, the funnel sometimes reaching to -earth, sometimes only part way, according to the pressure at which -precipitation begins, this pressure depending, of course, on the -percentage of humidity of the uprushing air. - -The form of the funnel-like cloud ere it reaches the earth is -interesting. Being an isobaric surface, it would support in static -equilibrium a free particle resting on it and sharing its rotatory -motion. The lower rounded part of the funnel is parabolic, the upper -outer part hyperbolic; the two together delineating the well-known -Rankine double vortex of hydrodynamics. Students of hydrostatics know -that when a glass of water is spun round its axis at a fixed velocity, -the dimple observed is of parabolic form, and if frozen will sustain -in repose a small shot resting on its surface and whirling with it. -Similarly the lower part of the funnel is parabolic because in it the -air rotates, as one solid body, while the broader part of the funnel is -hyperbolic because in it the air has a speed inversely proportional to -its radius of motion. - -If everywhere in a tornado the circular velocity of the inflowing air -were inversely proportional to the radius, as above assumed, the speed -near the axis would be indefinitely great. This cannot be admitted. -Practically, the inflow ceases when the centrifugal force of the -gyrating stratum equals the pressure urging it toward the axis. Within -this stratum is a column of air rotating everywhere with constant -angular velocity about the vortical axis, and thus having quite calm -air at its center. Outside this solidly rotating core the air spirals -radially inward and upward. Some idea of the stream lines in such -spiral flow may be obtained from Fig. 50 if a rapid circular motion be -added to the inward and upward velocity represented by the arrows. - -In the foregoing discussion no account of friction was taken. Near the -earth’s surface this dampens the whirl and centrifugal force, so that -the air flows more directly into the vortex, while farther aloft the -centrifugal force near the axis so effectually checks the inflow as -to allow the central core of air to rush up nearly unimpeded, as in -a walled flue, taking its draught mostly from the lower part. As a -consequence, the upward speed of the heated air in the tornado tube may -be enormous, supporting in its stream objects of considerable mass. - -[Illustration: FIG. 50.—FUNNEL-LIKE CLOUD SOMETIMES OBSERVED IN A -TORNADO.] - -The true horizontal speed anywhere in a tornado is compounded of the -velocities of gyration and of translation, as in the cyclone. Hence the -advancing side may be considerably the swifter and more destructive, -particularly more destructive since the impact of air increases as -the square of the velocity. If the vortex were stationary it would -be equally dangerous on all sides, standing erect and symmetrical; -but it drifts with the whole mass of air, sometimes quite swiftly and -often with varying speed of travel at different levels; thus, in its -slenderest forms, appearing bent and not infrequently twisted, as -it advances writhing serpentlike through the sky. Furthermore, the -intensity of whirl may fluctuate momentarily, with consequent shifting -of the isobaric surface, including that one whose form is visible -by reason of incipient condensation; and thus the funnel-like misty -tongue appears to dart earthward as a foggy downshoot from the cloud -above, whereas its parts are really rushing upward at all times very -swiftly, whether visible or not. This agile protrusion of the nimbus, -now a tongue, now a dark and mighty tower, is the strenuous part of -the storm, the abominated “twister” which the Kansan farmer sedulously -shuns, or peeps at from a hole in the ground. Unwelcome, indeed, are -its visitations, when, with mickle and multitudinous roar, it claps -his house in sudden darkness, hurls it aloft and sows its sacred relics -over all the adjoining township, “that with the hurly-burly hell itself -awakes.” - -Theory, as well as experience, accredits the tornado with vast energy -and power. For, suppose a surface stratum of air one mile in area -and one thousand feet thick to increase in absolute temperature one -per cent, thus uplifting the superincumbent atmosphere ten feet. The -total energy stored in this way equals the weight lifted multiplied by -its upward displacement. The weight is a ton per square foot and the -displacement is ten feet; hence the stored energy is ten-foot tons per -square foot of the heated tract, or about 280,000,000 foot tons for -the square mile of heated air. This is equivalent to the work of one -million horses for over a quarter of an hour. A goodly percentage of -this stored work may be converted into kinetic energy in the active -part of the dry tornado. It is the energy of a vast reservoir suddenly -gushing through a tall penstock. It is a colossal upward cataract, an -aërial Niagara, a Johnstown flood suddenly liberated and quickly spent. - -A vortex of that description possesses enormous devastating power, for -it is endowed with four destructive elements: rapid onset for razing, -violent spin for distorting, swift uprush for lifting, low pressure for -disrupting. These four grim powers may operate at once and in accord. -When, for example, they assault a house, the horizontal blasts push and -wrench it on the foundation, the cellar air suddenly expanding puffs it -aloft, the internal air bursts its walls or windows, the uprush carries -its members on high and scatters them wantonly to the four winds. -These powers are abundantly attested by authentic reports from many -localities. - -When the tornado appears as a misty column it is familiarly called -a “waterspout,” particularly if it appears over a sea or lake. As -already explained, the visible and cloudy portion of the column is -due to condensation of the aqueous vapor in the air, as it rushes -expanding and cooling into the low pressure part of the vortex. From -the lashed and rippling sea surface, where it upcones into the base of -the spout, some water is carried aloft as spray mingling with the mist -of the chilled vapor, but not necessarily in very large proportion, -and never rising in solid body to the cloud, as popularly supposed. On -the contrary, waterspouts, however massive and formidable looking, are -very tenuous, and may occur on land or water indifferently. Doubtless -they are better defined, more regular and more familiar over water, -and hence their name; but essentially they are vapor spouts, though -mingled at times with dust or spray. Owing to rapid precipitation of -the uprushing aqueous vapor, there may be heavy rainfall on all sides -of the waterspout, so that at sea it may be difficult for the observer -to ascertain how much of the downpour is salt water and how much is -fresh. On land the downpour is sometimes mingled with débris, and even -with live fish and frogs caught up from neighboring bodies Of water. -Copious hail also may fall with the rain, if the vortex be a lofty one. - -[Illustration: FIG. 51.—VERTICAL SECTION OF THE ST. LOUIS, MO., TORNADO -OF MAY 27, 1896, SHOWING THE VORTEX TUBES IN A THEORETICAL, TRUNCATED, -DUMBBELL-SHAPED VORTEX.] - -[Illustration: FIG. 52.—HORIZONTAL SECTION OF ST. LOUIS TORNADO OF MAY -27, 1896.] - -The following description and analysis of a representative spout is due -to Professor Bigelow of the U. S. Weather Bureau:[70] - - “The tornado may be illustrated by the St. Louis storm of May - 27, 1896. It is a truncated dumbbell vortex out off at the - ground on the plane where the inflowing angle is about 30°. - This vortex is much smaller than the hurricane, although of - the same type. It is about 1,200 meters high and about 2,000 - meters in diameter on the surface. The vortex tubes are shown - in Figs. 51 and 52. In these figures can be seen the vortex - tubes, geometrically spaced, through each of which the same - amount of air rises. The rotating velocity is greatest about - 300 meters above the ground, but the dimensions are such as to - produce enormous velocities in the lower levels. The radius in - the outer tube is taken to be 960 meters, and the inner tube - 55 meters. The radial inward velocity on the outer tube is—8 - meters per second; on the outer tube the tangential velocity - is 13 meters per second, and on the inner 224 meters per - second; on the outer tube the vertical velocity is 0.27, and - on the inner tube it is 80 meters per second. On the outer - tube the total velocity is 15 meters per second, and on the - inner tube 270 meters per second. The volume of air ascending - in each tube is 774,500 cubic meters per second. On account - of the distortion of the theoretical vortex, due to the - cutting of the lower portion by the truncated plane, and to the - progressive motion of the whole system that constitutes the - tornado, there is difficulty in computing the pressure to fit - these observed velocities and radii. - - “Tornadoes occur in the southern and southeastern quadrants of - areas of low pressure, along the borders of the cold and the - warm masses which entered into the structure of the cyclone. - When a cold mass is superposed upon a warm mass, as was the - case at St. Louis, a tornado will occur if the difference in - specific gravity be sufficient to inaugurate a violent mixing, - and the rotation be about a vertical axis, instead of about a - horizontal axis, as in the case of thunderstorms.” - -[Illustration: FIG. 53.—VERTICAL SECTION OF SHORT TORNADO.] - -The size and form of waterspouts alter greatly with the state of the -atmosphere. As Ferrel observes, they may vary “from that of a cloud -brought down over a large area of the earth’s surface in a tornado -where the air is nearly saturated with vapor and the general base of -the clouds very low, somewhat as represented in Fig. 53, to that which -occurs when the air is very dry, and when the tornadic action is barely -able to bring the cloud down from a great height into a slender spout -of small diameter, somewhat as represented in Fig. 54. Horner says that -their diameters range from 2 to 200 feet, and their heights from 30 -to 1,500 feet. Dr. Reye states that their diameters on land, at base, -are sometimes more than 1,000 feet. Oersted puts the usual height of -waterspouts from 1,500 feet to 2,000 feet, but states that in some rare -cases they cannot be much less than 5,000 or 6,000 feet. On the 14th of -August, 1847, Professor Loomis observed a waterspout on Lake Erie, the -height of which, by a rough estimate, was a half mile, and the diameter -about 10 rods at the base and 20 rods above. - -“Judge Williams, in speaking of the tornado of Lee’s Summit, where he -saw it, says: ‘It seemed to be about the size of a man’s body where it -touched the clouds above, and then tapered down to the size of a mere -rod.’” - -[Illustration: FIG. 54.—VERTICAL SECTION OF A TALL TORNADO.] - -When the tornado vortex is so tall and strong as to carry raindrops up -to freezing strata it is commonly known as a hailstorm. The congealing -occurs usually in those isobaric surfaces which dip down in the center -of the vortex, but reach only part way to the earth. As indicated -in Fig. 55, the clear aqueous vapor near the earth is condensed to -cloud on crossing an isobaric surface of sufficiently low pressure -and temperature; then it proceeds as mingled cloud and rain till it -crosses the freezing isobar into the region of snow and hail formation; -thence finally curves outwardly to stiller air and descends as a cloud -of mingled vapor, rain and frozen parts. Of this frozen shower one -part may come to earth as hail or rain, the snow and sleet melting on -the way; while another part may be redrawn into the swift uprush, and -carried aloft till its frozen drops, or pellets, have grown so large by -accretion as to plunge to earth by sheer bulk, even though they must -traverse a furious ascending wind. A good illustration from Nature of -this cycle in the center of a hailstorm is presented in the following -by Mr. John Wise, America’s adventurous pioneer balloonist: - - “This storm originated over the town of Carlisle, Pa., on - the 17th of June, 1843. I entered it just as it was forming. - The nucleus cloud was just spreading out as I entered the - vortex unsuspectingly. I was hurled into it so quickly that I - had no opportunity of viewing the surroundings outside, and - must therefore confine this relation to its internal action. - On entering it the motions of the air swung the balloon to - and fro and around in a circle, and a dismal, howling noise - accompanied the unpleasant and sickening motion, and in a - few minutes thereafter was heard the falling of heavy rain - below, resembling in sound a cataract. The color of the cloud - internally was of a milky hue, somewhat like a dense body - of steam in the open air, and the cold was so sharp that my - beard became bushy with hoar frost. As there were no electric - explosions in this storm during my incarceration, it might - have been borne comfortably enough but for the seasickness - occasioned by the agitated air-storm. Still, I could hear - and see, and even smell, everything close by and around. - Little pellets of snow (with an icy nucleus when broken) were - pattering profusely around me in promiscuous and confused - disorder, and slight blasts of wind seemed occasionally to - penetrate this cloud laterally, notwithstanding there was an - upmoving column of wind all the while. This upmoving stream - would carry the balloon up to a point in the upper clouds, - where its force was expended by the outspreading of its - vapor, whence the balloon would be thrown outward, fall down - some distance, then be drawn into the vortex, again be carried - upward to perform the same revolution, until I had gone through - the cold furnace seven or eight times; and all this time the - smell of sulphur, or what is now termed ozone, was perceptible, - and I was sweating profusely from some cause unknown to me, - unless it was from undue excitement. The last time of descent - in this cloud brought the balloon through its base, where, - instead of pellets of snow, there was encountered a drenching - rain, with which I came into a clear field, and the storm - passed on.” - -As might be expected the hailstones vary much in form, size and -quantity. If by chance any stones become slightly flattened they ride -level in the ascending current, and hence by aggelation grow most -rapidly on the periphery which is a line of diminished pressure. At -times they are more or less oval, and again they appear as fragments of -considerable masses of ice, broken perhaps by collision in the violent -parts of the tornado tube. Their great variety in shape and bulk may be -appreciated from the following extracts taken from the records of the -Signal Service: - -[Illustration: FIG. 55.—VERTICAL SECTION OF A HAIL TORNADO.] - -In _Professional Paper of the Signal Service No. 4_, describing the -tornadoes of May 29th and 30th, 1879, in Kansas, Nebraska, Missouri, -and Iowa, this passage occurs relative to a tornado at Delphos, Mo.: - - “On the farm of Mr. Peter Bock, in the adjoining township of - Fountain, about 4 miles W. of the storm’s centre, and during - the hailstorm that preceded the tornado, masses of ice fell as - large as a man’s head, breaking in pieces as they struck the - earth. One measured 13 inches in circumference, another 15, and - a hole made by one that fell near the place of Mr. J. H. Kams - measured 7 inches across one way and 8 the other. This immense - fragment of aërial ice broke into small pieces, so that its - exact size could not be determined.” - -The following description is given of the tornado that visited Lincoln -County, Neb., at that time: - -“At first the hailstones were about the size of marbles, but they -rapidly increased in diameter until they were as large as hens’ eggs -and very uniform in shape. After the precipitation had continued about -fifteen minutes, the wind ceased and the small hail nearly stopped, -when there commenced to fall perpendicularly large bodies of frozen -snow and ice, some round and smooth and as large as a pint bowl, others -inclined to be flat, with scalloped edges, and others resembled rough -sea-shells. One of the latter, after being exposed an hour to the sun, -measured fourteen inches in circumference.” - -The following was reported by the Signal Service observer at Fort -Elliott, Tex., 1888: - - “A thunder-storm began at 4.10 P.M. and ended at 7.40 P.M., - moving from southwest to northwest. Hail began at 5.18 P.M. - and ended at 5.26 P.M., the hailstones being spheroidal in - shape and about two inches in diameter; formation, solid snow. - The ‘break’ (hills) at the foot of the plains several miles - northwest of station were absolutely white with hailstones for - three hours after the storm. This was observed by everybody - at the station; on the morning of the 26th I walked down to - the Sweetwater Creek, three fourths of a mile distant, and saw - great banks of hailstones which had been washed down during the - night. The bottoms along the Sweetwater were literally covered - with banks of hailstones from six to eight feet in depth. It - was estimated that there was enough hail to cover ten acres to - a depth of six feet. The hailstones killed five horses which - were out on the prairie on a ranch six miles north of station. - The Sweetwater Creek was higher than ever known before, the - freshet destroying nearly the entire post garden. The high - water is supposed to have been caused by a ‘cloud-burst’ at - or near the foot of the plains, where the Sweetwater has its - source; there was only 0.36 inch of rainfall at the station. On - Sunday, May 27th, hailstones were collected on the banks of the - Sweetwater, which had been washed down and lay in drifts 6 feet - deep, actual measurement by the observer.” - -When, after imprisonment and long sustention in a powerful tornadic -vortex, the accumulated rain or hail finally breaks through and pours -down to earth, in solid cataract, the phenomenon is commonly called -a cloud-burst. The foregoing example is a partial illustration. -The following is quoted from Espy, describing a cloud-burst near -Hollidaysburg, Penn., in which the water seems to have poured down -nearly in a solid stream: - - “On examining the northern side of this ridge, large masses - of gravel and rocks and trees and earth, to the number of 22, - were found lying at the base on the plain below, having been - washed down from the side of the ridge by running water. The - places from which these masses started could easily be seen - from the base, being only about 30 yards up the side. On going - to the head of these washes they were found to be nearly round - basins from 1 to 6 feet deep, without any drains leading into - them from above. The old leaves of last year’s growth, and - other light materials, were lying undisturbed above, within an - inch of the rim of these basins, which were generally cut down - nearly perpendicularly on the upper side, and washed out clean - on the lower. The greater part of these basins were nearly of - the same diameter, about 20 feet, and the trees that stood in - their places were all washed out. Those below the basin were - generally standing, and showed by the leaves and grass drifted - on their upper side how high the water was in running down the - side of the ridge; on some it was as high as three feet. It - probably, however, dashed up on the trees above its general - level.” - -Dry whirlwinds of moderate size, but sometimes of considerable -violence, frequently occur in clear weather when the percentage of -humidity is small and when the vertical temperature gradient is -unusually pronounced. In this case there may be strong agitation of -the air, rendered visible at the earth’s surface by light débris on -land, or boiling of the water at sea; but the main body of the tube is -invisible and free from mist except high up where precipitation begins, -capped by a growing patch of white cloud in a clear sky, and which -may gradually broaden and condense sufficiently to cause a shower of -rain. On land the dry whirlwind may be delineated as a tall column, by -whirling dust or sand. In this case, if the gyration is violent, the -central core may appear clean and clear owing to the centrifugal force -which keeps the grains out where they are balanced by the pressure of -the inrushing air. In such vortices the sand spout may appear to be -hollow as in the case of waterspouts whose interior cores are free -from cloud or condensed vapor. On the other hand, myriads of mild -transparent whirlwinds unmarked, except by down or humanly invisible -dust, or dim aërial refractions, may frisk and play in the boundless -sky unnoticed by the blunt eyes of men, yet constantly engaged in -generating or marshaling the clouds and in buoying upward the ponderous -eagles, the vultures and the whole brood of passive flyers whom we -have not yet learned to emulate. Thus when we remember that an upward -trend of air of scarcely one yard per second, and too feeble to support -a falling hair, is yet sufficient to carry the condor and albatross -without wing beat, it seems important to explore these minor vortices -and to ascertain their availability and practical usefulness for human -soaring. - - - - - CHAPTER XVII - - THUNDERSTORMS, WIND GUSTS - - -Still another interesting kind of aërial disturbance is the familiar -heat thunderstorm. This is not synonymous with those electrified -tornadoes and cyclones which are accompanied by thunder and lightning, -sometimes of great violence. Most tornadoes are thunderstorms, but -not vice versa. The thunderstorm is not essentially a vortex, but -rather a wind squall marked by sudden changes of temperature and -pressure, bearing with it massive clouds fraught with rain, or hail, -and disruptive electric charges flashing frequently to earth, or -from point to point in the sky. Its approach is usually announced by -rumbling thunder and heavy black clouds along the horizon. Its duration -is brief, varying from a few minutes to an hour or two. Further -characteristics are thus expressed by Moore: - - “On land, thunderstorms occur most frequently at specific hours - of the day or night, such as 3 to 5 in the afternoon or 9 to 10 - in the evening and sometimes even at 2 or 3 A.M., but no such - diurnal period is observed in midocean. The phenomena usually - occur in a pretty regular order of succession. After several - hours of fair weather, with gentle winds, there comes a calm; - the cumulus clouds grow larger, the lower stratum of clouds is - seen to be moving rapidly; gusts of wind start up with clouds - of dust, rain is seen to be falling at a distance; the movement - of rain and dust shows that the wind is blowing out from this - rain cloud near the ground no matter which way the rainy region - is advancing; a few large drops fall from slight clouds and - then suddenly the heavy rain begins. Lightning that may have - occurred during the preceding few minutes becomes more frequent - and more severe as the rain increases. After the maximum - severity of rain and wind, the lightning also diminishes or - entirely ceases, and we are soon able to say that the storm has - passed by. If we watch its retreat from us in the afternoon - we shall see the rear of a great cumulus on which the sun is - shining, but through whose dark-blue curtain of cloud and rain - nothing save occasional lightning is visible. After the storm - has passed, the lower atmosphere soon becomes appreciably - cooler and drier, the sky is nearly clear of clouds, and the - wind has shifted to some other point of the compass than that - which prevailed before the storm.” - -The genesis of thunderstorms is varied and manifold. In one simple -type, a large tract of heated air in the unstable state and with a high -percentage of humidity swells upward at the center, the ascending moist -air forming, at the precipitation altitude, a growing cloud which may -become very broad, dark and bulky, drifting along over the earth with -the prevailing current. Eventually rain begins to form, or may be hail -or snow, if the heated column reaches to a great height. The falling -shower cools the air from the cloud down to the earth, increasing its -density and materially weighting it with the descending liquid or -solid particles. The showery column then sinks, especially along its -inner part where it is maturest, thus causing an outrush of cool air -along the earth, the immediate forerunner and herald of the rain. This -outrushing current pushes upward the environing clear moist air, thus -forming new margins of massive cumuli around the older nimbus widening -within, showering, cooling and sinking. Thus the rain area is broadened -and propagated, sometimes with nearly equal speed in all directions, -but generally fastest in the direction of the most unstable condition, -or of the then prevailing drift of the atmosphere. Indeed, the forward -cloud ranks may far outspeed the wind, seeming by their imperious -bluster and gigantic gloom to commandeer new recruits, as if by magic, -out of the clear sky. Before this solemn mustering and turbulent front -of the storm the black vapors suddenly startled into visible shape, -rush buoyantly upward in ragged shreds, like smoke from unseen fires, -and quickly blend with the general array of compact cloud expanding -across the sky. Again, several thunderstorms, merged like a mountain -range in solid phalanx, may sweep abreast over a continent, with long -horizontal[71] roll, ever rising in front and upheaving the sultry -air, thus replenishing perpetually the ponderous cumuli which form -the vanguard of this far-flung and titanic march of the clouds. Such -a storm is usually powerful and persistent, commonly enduring until -the sun’s decline and the shades of night have cooled the lower air, -and thus allayed the commotion by enfeebling the forces that favor its -progress. - -The speed of rise of the air beneath the base of the thunderhead is -a question of some interest in aëronautics. If the ascent be so much -as a foot or two per second, one may expect the vultures to prefer -soaring beneath the thundercloud during its formative period. Here -also the aëroplanist might attempt a record flight, if the cloud were -high enough to be out of his way. But if he ventured to penetrate the -base of the thunderhead, he might find the turmoil too irregular and -strenuous for his comfort. - -Of like interest is the long aërial swell that leads the advancing -storm. When will aviators make this the theater of their adventurous -frolic, careering playfully before the brow of the tempest and the -harmless rage of the lightning, gay-winged heralds of the coming -tumult, sailing perhaps with slackened motive power, yet swift and -secure as the storm-riding petrels at sea? - -Besides the winds and aërial currents commonly studied by -meteorologists, are the minor disturbances which affect more -particularly the wayfarers of the sky, whether birds or men. The -atmosphere quite usually is vexed with invisible turmoils; most -sensible, indeed, over rough territory, but conspicuous also above -the smooth terrene, and at all elevations from earth to the highest -cloudland. Before sunrise, and generally in weather uniformly overcast, -these miscellaneous and nondescript movements of the air are least -active, for any given speed of the general drift of the atmosphere; -but when the sun shines and the soil is nonuniformly heated, the -disturbances become most pronounced. A whole troop of playful zephyrs -rise and set with the sun, in addition to the diurnal winds already -studied. Over the dusty plain they reveal their presence and shape -in those coiling columns that constitute the safety vents of the -atmosphere, and obviate the disruptive violence of the uprush that -would occur should a considerable region of surface air become -excessively heated. Over the city, particularly in winter, the local -turmoils of the atmospheric surf are revealed in the play of a thousand -smoky columns, and better still, when it snows, by the incessant -swell and veering of the flaky flood whose surges and eddies bewilder -the vision by their complexity. Over the water the clouds of fog -and steaming vapor are the best index of the local zephyrs, where, -it must be remembered, the rising and veering of the vapor wreaths -accompany like motions in the atmosphere. Over the forest, field and -meadow the interminable wandering of thistle down and gauzy shreds of -vegetation, now fast, now slow, now high aloft, then sheer earthward, -indicate what erratic and perpetual motions prevail throughout the open -country even on the stillest days. In the deep bosom of the atmosphere, -the parallel ranks of the cirri all across the sky mark the crests -of undulations quite as regular and tumultuous as the billows of a -wind-swept sea; while the fierce seething and upsurging of the separate -cumuli manifest the operation of vortices of prodigious energy. These -visible billows and whirlwinds suggest an infinitude of transparent -ones hardly less powerful, at the various levels unmarked by clouds. -For wherever two streams of abnormally graded densities neighbor each -other, a readjustment may occur agitating the entire region with a host -of pulsations, squalls, cataracts and fountains which the bird and -navigator must parry with proportionate care and skill. - -And it is because of the amazing resistance of these wandering zephyrs, -waves and eddies that they demand the attention of aëronauts; nay, -more, it is because of the substantial labor they can perform when -adroitly encountered and duly employed. For the simplest elements of -aërodynamic science make clear that a rising zephyr hardly strong -enough to support a falling leaf is adequate to sustain the heaviest -soaring birds and aëroplanes gliding swiftly through it. In fact, the -sailors of fast air ships feel a heavy impulse and distinct shock in -plowing those mild cross winds which, to the fixed observer, seem not -like blasts, but rather as gentle swells or harmless currents. These, -therefore, have been made the subject of investigation by various -students of aëronautics. - -The first incentive to the instrumental study of the fluctuations -of the wind in speed and direction seems to have been the hope to -furnish a quantitative basis for various theories of soaring flight. -Pénaud,[72] in 1875, had explained this phenomenon by postulating -an upward current. Lord Rayleigh,[73] in 1883, had made the more -general assumption of a wind having either a variable speed or a -variable direction as a necessary and sufficient condition for such -flight. Marey,[74] in 1889, and Langley,[75] in 1893, gave elementary -qualitative explanations of soaring in a horizontal wind of variable -velocity, though neither adduced concrete data to prove that the feat -could be performed in an actual wind. Each and all of those theories -may be sound enough in the abstract, but to show that they represent -realities of art or Nature they should be applied to a concrete -instance of soaring of a machine or a bird of known resistance, in a -wind of known variability. - -To such end the writer in 1892 devised an anemograph for recording -simultaneously the speed of the wind and its horizontal and vertical -components of direction, while Dr. Langley devised a very light and -delicate cup anemometer for recording the variations of wind speed in -a horizontal plane, but not the changes of direction. Both instruments -were set up in January, 1893, and both investigations were published -with the _Proceedings of the International Conference on Aërial -Navigation_ of that year; but neither investigation was pushed far -enough to prove conclusively the possibility of a particular bird -or model soaring in the particular wind recorded. The two together -did, however, reveal quite astonishing fluctuations of the wind in -both speed and direction, results that have since received ample -exemplification in the more extended records of other observers. - -[Illustration: FIG. 56.—UNIVERSAL ANEMOGRAPH. (The vanes are high above -the point indicated by the break in the vertical pipe.)] - -Fig. 56 shows the recording anemometer for speed and double direction -constructed by the writer in 1892. A large weather vane was firmly -strapped to a vertical pipe which turned freely on ball bearings and, -by means of a small crank actuating a chronograph pencil, recorded its -fluctuations on a long sheet of paper winding on the drum from a roll -behind. On top of the pipe and about fifteen feet from the ground, -was mounted a carefully balanced horizontal vane, from which a fine -steel wire ran down the axis of the pipe to a fixed pulley, thence -to a second recording pencil. A third pencil recorded the beats of a -pendulum, thus standardizing the speed of the paper. A fourth pencil, -not shown, was designed to record the turns of an anemometer mounted -near the top of the pipe. The records of the wind speed thus secured -are omitted for lack of standardization, as the experiments were -prematurely terminated. - -[Illustration: FIG. 57.—RECORDS OF WIND VARIATION IN HORIZONTAL AND -VERTICAL DIRECTION.] - -Typical records of the wind direction are shown in Fig. 57 in which -the circles represent the paths swept by the wind-vane cranks that -operated the corresponding pencils. Both vanes, as shown by their -diagrams, veered quite frequently ten degrees in a short interval of -time, and not seldom twenty to thirty degrees. Frequently, also, it was -observed, in scanning the various records, that a rise or lull in the -wind speed was accompanied by a corresponding variation in direction; -but the observations were not sufficiently numerous and extended to -establish this phenomenon as a general occurrence. But as it can be -shown theoretically that a horizontal stream of air of constant cross -section and uniform velocity at each section, can not greatly fluctuate -in velocity from point to point, without more pronounced changes of -density than the barometer records, it naturally follows that the -stream must broaden where the air speed lags, and narrow where it -accelerates; in other words, it follows that there must be some change -in direction. The records were taken in the middle of a clear open -space of two hundred acres at Notre Dame University on a sunless day in -January, 1893, when the temperature was 24° F., and the wind eight to -twelve miles per hour. Their application to the theory of soaring need -not be considered here. - -Further studies of the wind pulsations were made by use of a toy -balloon attached to a long thread. The first trials are thus recounted -in the paper above cited: - - “After some preliminary tests from the top of the Physical - Laboratory of the Johns Hopkins University, during the Easter - vacation of 1893, I ascended the Washington Monument at - Baltimore, where I paid out the exploring line at a height - of 200 feet. The wind was blowing toward the southeast at - the speed of 25 to 35 miles per hour, and the sky, which had - remained clear till 3 o’clock, was rapidly darkening, with - indications of approaching rain. The balloon, when let forth, - immediately fell to a depth of 30 or 40 feet, being caught - in the eddy of the monument, then presently encountering - the unbiased current, sailed in it toward the southeast, - approximately level with the spool end of the thread. After - the balloon had drawn out 100 feet of thread I checked it to - observe the behavior of this much of the exploring line. The - balloon rose and fell with the tossing of the wind, but did - not flutter like a flag, as it would do if formed of irregular - outline. Neither did the thread flutter, nor do I believe there - is ever a tendency in a line greatly to flutter in a current - as does a flag or sail. Presently I paid out 300 feet of the - exploring line, whereupon the waves in the thread became quite - remarkable. The thread then, as a rule, was never approximately - straight. Sometimes it was blown into the form of a helix of - enormous pitch; at other times into the form of a wavy figure - lying nearly in a single vertical plane; and again, the entire - exploring line should veer through an angle of 40° to 60°, - either vertically or horizontally. The balloon, of course, - seldom remained quiet for more than a few seconds at a time, - but tossed about on the great billows like a ship in a storm. - Quite usually the billows could be seen running along the - line from the spool to the balloon, and, as a rule, several - different billows occupied the string at one time. - - “The observations just delineated, however curious they may - be, afford no adequate conception of the behavior of the air - currents over an open plane, nor at a great height above the - earth, because the Washington Monument at Baltimore stands but - 100 feet above the surrounding buildings, which undoubtedly - send disturbances to a greater height than 200 feet. To - supplement these explorations, therefore, I determined to - have them repeated from the top of the Washington Monument at - Washington and the Eiffel Tower at Paris.” - -Some months later in the year, the experiment was repeated at the top -of the Washington Monument in Washington, at a height of five hundred -feet. The balloon, with a stone attached, was paid out from the north -window of the monument till it reached the ground. Then the stone was -removed by an assistant who drew the balloon well away from the huge -eddy of the great shaft, and let it fly toward the east, drawing the -thread after it like a mariner’s log in the wake of a ship. When six -hundred feet of the thread had been let out, it was observed to veer in -all directions under the varying surges of the wind. These variations -seemed larger than could be expected from the wake of the shaft alone -near its summit, where it measures about thirty feet in thickness. - -Such qualitative observations, though interesting and suggestive, -are not wholly satisfactory. The same may be said of the study of -air currents by aid of smoke from tall chimneys. The eddy about such -columns may extend to a considerable height above them, and the wake -is farreaching. The experiments would therefore best be made from high -open-work towers above plane country or a broad sheet of water. - -A better method perhaps would be to liberate a pilot balloon, or -discharge a bomb giving a bright compact cloud, and to trace its path -by means of two cameras, as it floats from point to point in the -aërial current. The instruments, if suitably stationed, would give the -continuous space history of the floating object; that is, its actual -path and the speed at each part thereof, or, in other words, the -magnitude and direction of the velocity at each point. But, of course, -this method would not reveal the wind’s history at any given fixed -point, as recorded by the anemograph above described. - -[Illustration: FIG. 58.—RECORDS OF WIND SPEED OBTAINED BY LANGLEY.] - -Fig. 58 is a typical wind-speed record obtained by Langley in January, -1893, by means of a very light cup anemometer mounted eleven feet -above the north tower of the Smithsonian Institution, and 153 feet -from the ground. The abscissæ represent time in minutes, the ordinates -wind speed in miles per hour. The records were taken in cloudy weather -and in a south-southeast wind. Other records were taken during the -month of February, showing like deviations from the mean, though at -times more pronounced; for Dr. Langley noted that “the higher the -absolute velocity of the wind, the greater the relative fluctuations -which occur in it.” - -It will be observed from this record that, when the average speed was -about twelve miles an hour, the extreme fluctuation was rarely one -third greater or less than that, and on the average varied hardly -one sixth. It must be further added that the air on approaching the -anemometer had traversed a mile of the lower residential section of -the city, then crossed the body of the Smithsonian building, which -itself is half as high as the tower. It should be expected, therefore, -that this wind was, other things equal, naturally more turbulent than -if flowing in from a level plain. This surmise is justified by the -more extensive records of wind speeds shown in meteorological records -taken respectively in clear and in obstructed places. On the other -hand, even in level places where no obstruction is visible for several -miles, the wind, though it may be steady at one time, can at another -time be gustier than that shown in Langley’s record, according to the -state of the weather; for the gusts are not all due to neighboring -obstacles, but may be transmitted from afar, even from the depths of -the atmosphere. - -Assuming the wind speed at any instant to vary by one sixth of the -mean, its impactual pressure will then vary by thirty-six per cent of -the pressure of the mean wind, remembering that the pressure varies as -the square of the speed. This fluctuation of the impactual pressure -tallies fairly well with that found by Professor Marvin at the top of -Mount Washington, in 1890, by means of a pressure plate.[76] He found -the variation to be approximately thirty-five per cent of the mean -pressure. Professor Hazen, however, reports but little variation in -the wind speed in the free atmosphere well above the earth. In several -balloon ascensions he suspended from the basket a lead weight by means -of a cord to which was looped the thread of a toy balloon. He found -that the little balloon sometimes moved ahead if the weight sometimes -followed it, but that in general the relative motion was very feeble, -thus indicating that the fluctuations of the velocity in the depth of -the atmosphere at those times were very slight.[77] However this be for -such distances from the earth and its protuberances, the fluctuations -of wind speed found at meteorological stations sufficiently resemble -those reported by Dr. Langley. As corroborative evidence, the reader -may be referred to the wind records published in the _Interim Report_ -for 1909, of the British Advisory Committee for Aëronautics. - -Without the material evidence of commotion in the atmosphere, a -moment’s reflection will make clear that such turmoil must exist, even -over a vast, smooth plain, especially in bright weather, and more -particularly over bare ground in dry weather. For it is well known -that clear, dry air transmits radiation with very slight absorption, -when the sun is well toward the zenith, and hence that the temperature -in the depth of the atmosphere is but little changed from moment -to moment, due to the passage of sunlight. At the earth’s surface, -however, the air by contact with heating or cooling soil may change -temperature rapidly. The direct sunlight falling perpendicularly upon -a perfectly absorbent material transmits nearly two calories of heat -per minute to each square centimeter of the receiving surface. It -would, therefore, under favorable circumstances, elevate by nearly -two degrees C. per minute a layer of water one centimeter deep, or -a layer of air something over a hundred feet thick, if all the heat -falling on the assumed surface were communicated to the neighboring air -stratum. In practice, a large percentage of the incident sunlight is -reflected and radiated by the soil, into sidereal space without heating -the air. But every one per cent of it caught up by the air in contact -with the earth is sufficient to heat a layer roughly one foot thick -one degree per minute. Hence, unless the heated air streamed upward -continually, the layer next the earth would quickly be raised to a -very abnormal temperature, which would result in a violent uprush. The -gradual ascension of the surface air may take place in large or small -columns, or in both kinds at once. In either case, the composition of -the ascensional motion with the general movement of the wind due to -barometric gradient must cause gustiness and marked irregularity of -speed and direction. - -Various causes have been assigned for the gustiness of the winds. -Ferrel and many other writers assume that the air, especially near -the earth, is full of small vortices rotating about axes of various -inclination. These whirls, on passing squarely across a weather vane, -cause it to point one way for a moment, then presently the opposite -way, while if they cross obliquely they cause a like sudden veering of -the vane, but less extensive. - -Helmholtz has proved that in the atmosphere strata of different -densities come at regular intervals to be contiguous one above -the other, and thus to beget conditions favorable to the formation -of aërial waves, sometimes so large as to set the lower regions of -air into violent commotion and thereby generate the so-called gusty -weather. He has summarized as follows some of the important conclusions -of his dynamic analysis.[78] - -“As soon as a lighter fluid lies above a denser one with well-defined -boundary, then evidently the conditions exist at this boundary for -the origin and regular propagation of waves, such as we are familiar -with on the surface of water. This case of waves, as ordinarily -observed on the boundary surfaces between water and air, is only to be -distinguished from the system of waves that may exist between different -strata of air, in that in the former the difference of density of the -two fluids is much greater than in the latter case. It appeared to me -of interest to investigate what other differences result from this in -the phenomena of air waves and water waves. - -“It appears to me not doubtful that such systems of waves occur with -remarkable frequency at the bounding surfaces of strata of air of -different densities, even although in most cases they remain invisible -to us. Evidently we see them only when the lower stratum is so nearly -saturated with aqueous vapor that the summit of the wave, within which -the pressure is less, begins to form a haze. Then there appear streaky, -parallel trains of clouds of very different breadths, occasionally -stretching over the broad surface of the sky in regular patterns. -Moreover, it seems to me probable that this, which we thus observe -under special conditions that have rather the character of exceptional -cases, is present in innumerable other cases when we do not see it. - -“The calculations performed by me show, further, that for the observed -velocities of the wind there may be formed in the atmosphere not only -small waves, but also those whose wave lengths are many kilometers -which, when they approach the earth’s surface to within an altitude -of one or several kilometers, set the lower strata of air into -violent motion and must bring about the so-called gusty weather. The -peculiarity of such weather (as I look at it) consists in this, that -gusts of wind often accompanied by rain are repeated at the same place, -many times a day, at nearly equal intervals and nearly uniform order of -succession.” - -Commandant Le Clement de Saint-Marcq has drawn some interesting -conclusions from the hypothesis that an ordinary wind consists of a -uniform current on which is superposed periodic motions in the wind’s -main direction and also at right angles thereto. But he has not -established his hypothesis by adequate observations. He assumes the -pulsations to be simple harmonic motions, which of course they would be -if they were plane compressional waves; but at the same time he shows -that the fluctuations are too large to be compressional waves, with the -concurrent slight variations of the barometric pressure. - -It is still a question whether the pulsations of the natural wind be -harmonic. If so, the speed records should be sine curves, and the to -and fro acceleration of any mass of moving air should be variable for -any given pulsation. But the few records available show in many parts a -constant acceleration of the wind speed throughout a particular swell -or lull of velocity, indicating that the pulsations are not generally -simple harmonic ones. - -In scanning the wind-speed records published by Langley, so many -instances of uniform wind acceleration are noticed that one naturally -inquires whether the rate of gain of velocity be sufficient to sustain -in soaring flight an aëroplane or bird held to the wind solely by -its inertia, as Langley believed to be possible. The total forward -resistance of a well-formed aërial glider, or bird, may be taken as -one eighth of its weight; hence, if poised stationary in its normal -attitude of flight, it will just be sustained by a direct head wind -having a horizontal acceleration of one eighth that of gravity, or -four feet per second. Now, the most favorable parts of the record here -shown (Fig. 58) exhibit nowhere an acceleration so great as four feet -per second, and on the average far less than that, as may be proved -by sealing the diagram. Hence, the wind here recorded was wholly -inadequate to support by its pulsative force either bird or man. But -as this record is a fair representative of all those published by Dr. -Langley, it follows that such pulsations can at best merely aid in -soaring when happily and adroitly encountered; but that they cannot -fully sustain soaring at any level, much less during ascensional flight -to great altitudes, or migrational flight to vast distances. It still -remains, therefore, to ascertain what kind of aërial currents are -adequate to sustain those marvelous feats of soaring on passive pinions -which for ages have been the delight and wonder of all keen observers, -and which are of such enduring interest to mankind. This investigation, -however, appertains more particularly to the science of applied -aërodynamics. - - - - - APPENDICES - - - - - APPENDIX I - - STRESS IN A VACUUM BALLOON[79] - - _By A. F. Zahm_ - - -As inventors frequently propose the construction of a vacuum balloon, -to secure buoyancy without the use of gas, it may be desirable to -estimate the strength of material required to resist crushing, say in a -spherical balloon. - -The unit stress in the wall of a thin, hollow, spherical balloon -subject to uniform hydrostatic pressure, which is prevented from -buckling, is given by equating the total stress on a diametral section -of the shell to the total hydrostatic pressure across a diametral -section of the sphere, thus: - - 2π_rtS_ = π_pr^2_ - -in which _S_ may be the stress in pounds per square inch, _p_ the -resultant hydrostatic pressure in pounds per square inch, _r_ the -radius of the sphere, _t_ the wall thickness. - -The greatest allowable mass of the shell is found by equating it to the -mass of the displaced air, thus: - - 4π_r_^2_t_ς_{1} = 4π_r_^3ς_{2}/3 - -in which ς_{1} is the density of the wall material, ς_{2} the density -of the atmosphere outside. - -Now, assuming _p_ = 15, ς_{1}/ς_{2} = 6,000, for steel and air, the -equations give: - - _S_ = 3_p_ς_{1}/2ς_{2} = 45 × 6,000/2 = 135,000 pounds - -per square inch as the stress in a steel vacuum balloon. - -For aluminum ς_{1} is less, but the permissible value of _S_ is also -less in about the same proportion. - -The last equation shows that for a given material and atmospheric -environment, the stress in the shell or wall of the spherical balloon -is independent of the radius of the surface. It is also well known -that the stress is less for the sphere than for any other surface. -Hence, no surface can be constructed in which _S_ will be less than -3_p_ς_{1}/2ς_{2}. The argument is easily seen to apply to a partial -vacuum balloon, since a balloon of one nth vacuum will float a cover of -but one nth the mass and strength. - -The above result was obtained on the assumption that the shell was -prevented from buckling. As a matter of fact, it would buckle long -before the crushing stress could be attained. We must conclude, -therefore, that while a vacuum balloon has alluring features, the -materials of engineering are not strong enough to favor such a -structure. Perhaps it is nearer the truth to say that such a project is -visionary, with the materials now available. - - • • • • • - -A like argument applies to the balloon reservoir in which it has -been proposed to compress the surplus gas taken from a balloon hull -on expansion of its contents by change of level or temperature. If a -given mass of gas obeying Boyle’s law be pumped into a receiver of -given shape and mass, the resultant stress in the receiver wall will be -independent of the size. Hence the material of the proposed reservoir, -if expanded to the size of the hull itself, will weigh the same, and -suffer the same increment of unit stress, for a given mass increment of -gas. Hence, instead of pumping the above-mentioned gas surplus from the -hull into the reservoir, this latter may be discarded and its mass of -material spread over the hull itself. This argument applies only if the -shapes of hull and reservoir be equally effective, as, for example, if -both be cylindrical. - - - - - APPENDIX II - - AËRONAUTIC LETTERS OF BENJAMIN FRANKLIN - - - PASSY, Aug. 30, 1783. - -On Wednesday, the 27th instant, the new aërostatic Experiment, invented -by Messrs. Montgolfier of Annonay, was repeated by M. Charles, -Professor of experimental Philosophy at Paris. - -A hollow Globe 12 feet Diameter was formed of what is called in England -Oiled Silk, here Taffetas gommé, the Silk being impregnated with a -Solution of Gum elastic in Linseed Oil, as he said. The Parts were -sewed together while wet with the Gum, and some of it was afterwards -passed over the Seam, to render it as tight as possible. - -It was afterwards filled with inflammable Air that is produced by -pouring Oil of Vitriol upon Filings of Iron, when it was found to have -a tendency upwards so strong as to be capable of lifting a Weight of 39 -Pounds, exclusive of its own Weight which was 25 lbs and the Weight of -the Air contain’d. - -It was brought early in the morning to the Champ de Mars, a Field in -which Reviews are sometimes made, lying between the military School and -the River. There it was held down by a Cord till 5 in the afternoon, -when it was to let loose. Care was taken before the Hour to replace -what Portion had been lost, of the inflammable Air, or of its Force, by -injecting more. - -It is supposed that not less than 50,000 People were assembled to see -the Experiment, The Champ de Mars being surrounded by multitudes, and -vast Numbers on the opposite Side of the River. - -At 5 O’clock Notice was given to the Spectators by the Firing of two -Cannon, that the Cord was about to be cut. And presently the Globe was -seen to rise, and that as fast as a Body of 12 feet Diameter, with a -force only of 39 Pounds, could be suppos’d to remove the resisting Air -out of its Way. There was some Wind, but not very strong. A little -Rain had wet it, so that it shone, and made an agreeable appearance. -It diminished in Apparent Magnitude as it rose, till it enter’d the -Clouds, when it seem’d to me scarce bigger than an Orange, and soon -after became invisible, the Clouds concealing it. - -The multitude separated, all well satisfied and delighted with the -Success of the Experiment, and amusing one another with discourses of -the various uses it may possibly be apply’d to, among which many were -very extravagant. But possibly it may pave the Way to some Discoveries -in Natural Philosophy of which at present we have no conception. - -A Note secur’d from the Weather had been affix’d to the Globe, -signifying the Time & Place of its Departure, and praying those who -might happen to find it, to send an account of its state to certain -Persons at Paris. No News was learned of it till the next Day, when -information was received that it fell a little after 6 o’clock, at -Gonesse, a Place about four Leagues Distance, and that it was rent -open, and some say had ice in it. It is suppos’d to have burst by the -Elasticity of the contain’d Air when no longer compress’d by so heavy -an Atmosphere. - -One of 38 feet Diameter is preparing by Mr. Montgolfier himself, at the -Expence of the Academy, which is to go up in a few days. I am told it -is constructed of Linen & Paper, and is to be filled with different -Air, not yet made public, but cheaper than that produc’d by the Oil of -Vitriol, of which 200 Paris Pints were consum’d in filling the other. - -It is said that for some Days after its being fill’d the Ball was found -to lose an eighth Part of its Force of Levity in 24 Hours; Whether this -was from Imperfection in the Tightness of the Ball, or a Change in the -Nature of the Air, Experiments may easily discover.... - -M. Montgolfier’s Air to fill the Globe has hitherto been kept secret; -some suppose it to be only common Air heated by passing thro’ the Flame -of burning Straw, and thereby extreamly rarefied. If so, its Levity -will soon be deminish’d by Condensation, when it comes into the cooler -Region above.... - -P. S. I just now learned that some observers say, the Ball was 150 -Seconds in rising, from the cutting of the Cord till hid in the Clouds; -that its height was then about 500 Toises, but, being moved out of -the Perpendicular by the Wind, it had made a Slant so as to form a -Triangle, whose base on the Earth was about 200 Toises. It is said the -Country People who saw it fall were frightened, conceiv’d from its -bounding a little, when it touched the Ground, that there was some -living Animal in it, and attack’d with Stones and Knives, so that it -was much mangled; but it is now brought to Town and will be repair’d. - -The great one of M. Montgolfier is to go up, as is said, from -Versailles, in about 8 or 10 days. It is not a Globe but of a different -Form, more convenient for penetrating the Air. - -It contains 50,000 cubic Feet, and is supposed to have Force of Levity -equal to 1,500 pounds weight. A Philosopher here, M. Pilâtre du Rozier, -has seriously apply’d to the Academy for leave to go up with it, in -order to make some experiments. He was complimented on his Zeal and -Courage for the Promotion of Science, but advis’d to wait till the -management of these Balls was made by Experience more certain & safe. -They say the filling of it in Montgolfier’s Way will not cost more -than half a Crown. One is talk’d of to be 110 feet Diameter. Several -gentlemen have ordered small ones to be made for their Amusement. -One has ordered four of 15 feet Diameter each; I know not with what -Purpose; but such is the present Enthusiasm for promoting and improving -this Discovery, that probably we shall soon make considerable Progress -in the art of constructing and using the Machines. - -Among the Pleasanteries Conversation produces on this subject, some -suppose Flying to be now invented, and that since Men may be supported -in the Air, nothing is wanted but some light handy instrument to give -and direct Motion. Some think Progressive Motion on the Earth may -be advanc’d by it, and that a Running Footman or a Horse slung and -suspended under such a Globe so as to have no more of Weight pressing -the Earth with their Feet, then Perhaps 8 or 10 pounds, might with a -fair Wind run in a straight Line across Countries as fast as that Wind, -and over Hedges, Ditches & even Waters. It has been even fancied that -in time People will keep such Globes anchored in the Air, to which by -Pullies they may draw up Game to be preserved in the Cool & Water to be -frozen when Ice is wanted. And that to get Money, it will be contriv’d -to give People an extensive View of the Country, by running them up in -an Elbow Chair a Mile high for a Guinea, &c., &c. - - B. FRANKLIN. - - - PASSY, Nov. 22d, 1783. - -... Enclosed is a copy of the Proces verbal taken of the Experiment -yesterday in the Garden of the Queen’s Palace la Muette, where the -Dauphin now resides, which being near my House I was present. This -Paper was drawn up hastily, and may in some Places appear to you -obscure; therefore I shall add a few explanatory Observations. - -This Balloon was larger than that which went up from Versailles and -carried the Sheep, &c. Its bottom was open, and in the middle of the -Opening was fixed a kind of Basket Grate, in which Faggots and Sheaves -of Straw were burnt. The Air rarefied in passing thro’ this Flame rose -in the Balloon, swell’d out its sides, and Fill’d it. - -The Persons who were plac’d in the Gallery made of Wicker, and attached -to the Outside near the Bottom, had each of them a Port thro’ which -they could pass Sheaves of Straw into the Grate to keep up the Flame, -& thereby keep the Balloon full. When it went over our Heads, we could -see the Fire which was very considerable. As the Flame slackens, the -rarefied Air cools and condenses, the Bulk of the Balloon diminishes -and it begins to descend. If those in the Gallery see it likely to -descend in an improper Place, they can by throwing on more Straw, & -renewing the Flame, make it rise again, and the Wind carries it farther. - -One of these courageous Philosophers, the Marquis d’Arlandes, did me -the honour to call upon me in the Evening after the Experiment, with -Mr. Montgolfier, the very ingenious Inventor. I was happy to see him -safe. He informed me that they lit gently, without the least Shock, and -the Balloon was very little damaged. - -This method of filling the Balloon with hot Air is cheap and -expeditious, and it is supposed may be sufficient for certain -purposes, such as elevating an Engineer to take a view of an Enemy’s -Army, Works, &c., conveying Intelligence into, or out of a besieged -Town, giving Signals to distant places, or the like. - -The other method of filling a Balloon with permanently elastic -inflammable Air, and then closing it is a tedious Operation, and -very expensive; Yet we are to have one of that kind sent up in a few -days. It is a Globe of 26 feet diameter. The Gores that compose it -are red and white Silk, so that it makes a beautiful appearance. A -very handsome triumphal Car will be suspended to it, in which Messrs. -Roberts, two Brothers, very ingenious Men, who have made it in concert -with Mr. Charles, propose to go up. There is room in this Car for a -little Table to be placed between them, on which they can write and -keep their journal, that is, take Notes of everything they observe, the -State of their Thermometer, Barometer, Hygrometer, &c., which they will -have more leisure to do than the others, having no fire to take care -of. They say they have a contrivance which will enable them to descend -at Pleasure. I know not what it is. But the Expence of this machine, -Filling included, will exceed, it is said, 10,000 Livres. - -This Balloon of only 26 feet diameter, being filled with Air ten times -lighter than common Air, will carry up a greater Weight than the other, -which tho’ vastly bigger, was filled with an Air that could scarcely be -more than twice as light. Thus the great Bulk of one of these Machines, -with the short duration of its Power, & the great Expence of filling -the other will prevent the Inventions being of so much Use as some may -expect, till Chemistry can invent a cheaper light Air producible with -more Expedition. - -But the Emulation between the two Parties running high, the Improvement -in the Construction and Management of the Balloons had already made -a rapid Progress; and one cannot say how far it may go. A few Months -since the idea of Witches riding thro’ the Air upon a Broomstick, and -that of Philosophers upon a Bag of Smoke, would have appeared equally -impossible and ridiculous. - -These Machines must always be subject to be driven by the Winds. -Perhaps Mechanic Art may find easy means to give them progressive -Motion in a Calm, and to slant them a little in the Wind. - -I am sorry this Experiment is totally neglected in England, where -mechanic Genius is so strong. I wish I could see the same Emulation -between the two Nations as I see between the two Parties here. Your -Philosophy seems to be too bashful. In this Country we are not so -much afraid of being laught at. If we do a foolish thing, we are the -first to laugh at it ourselves, and are almost as much pleased with -a Bon Mot or a Chanson, that ridicules well the Disappointment of a -Project, as we might have been with its Success. It does not seem to me -a good reason to decline prosecuting a new Experiment which apparently -increases the power of a Man over Matter, till we can see to what use -that power can be applied. When we have learnt to manage it, we may -hope some time or other to find Uses for it, as men have done for -Magnetism and Electricity, of which the first Experiments were mere -Matters of Amusement. - -This Experience is by no means a trifling one. It may be attended with -important Consequences that no one can foresee. We should not suffer -Pride to prevent our progress in Science. - -Beings of a Rank and Nature far superior to ours have not disdained -to amuse themselves with making and launching Balloons, otherwise we -should never have enjoyed the Light of those glorious objects that rule -our Day & Night, nor have had the Pleasure of riding round the Sun -ourselves upon the Balloon we now inhabit. - - B. FRANKLIN. - - PASSY, Dec. 1, 1783. - -In mine of yesterday I promised to give you an account of Messrs. -Charles & Roberts’ Experiment, which was to have been made this Day, -and at which I intended to be present. Being a little indispos’d, & -the Air cool, and the Ground damp, I declin’d going into the Garden -of the Tuilleries where the Balloon was plac’d, not knowing how long -I might be oblig’d to wait there before it was ready to depart; and -chose to stay in my Carriage near the Statue of Louis XV, from whence I -could well see it rise, & have an extensive View of the Region of Air -thro’ which, as the Wind sat, it was likely to pass. The Morning was -foggy, but about one o’clock the Air became tolerably clear; to the -great satisfaction of spectators, who were infinite. Notice having been -given of the intended Experiment several days before in the Papers, -so that all Paris was out, either about the Tuilleries, on the Quays -& Bridges, in the Fields, the Streets, at the Windows, or on the Tops -of Houses, besides the inhabitants of all the Towns & Villages of the -Environs. Never before was a philosophical Experiment so magnificently -attended. Some Guns were fired to give Notice that the departure of -the great Balloon was near, and a small one was discharg’d which went -to an amazing height, there being but little Wind to make it deviate -from its perpendicular Course, and at length the Sight of it was lost. -Means were used, I am told, to prevent the great Balloon’s rising so -high as might endanger its Bursting. Several Bags of Sand were taken -on board before the Cord that held it down was cut, and the whole -Weight being then too much to be lifted, such a Quantity was discharg’d -as to permit its Rising slowly. Thus it would sooner arrive at that -Region where it would be in equilibrio with the surrounding Air, and -by discharging more Sand afterwards, it might go higher if desired. -Between One & Two o’Clock, all Eyes were gratified with seeing it -rise majestically from among the Trees and ascend gradually above the -Buildings, a most beautiful Spectacle! When it was about 200 feet high, -the brave Adventurers held out and wav’d a little white Pennant, on -both sides their Car, to salute the Spectators, who return’d loud Claps -of Applause. The Wind was very little, so that the Object, tho’ moving -to the Northward, continued long in View; and it was a great while -before the admiring People began to disperse. The persons embark’d -were Mr. Charles, Professor of Experimental Philosophy, & zealous -Promotor of that Science; and one of the Messieurs Robert, the very -ingenious Constructors of the Machine. When it arrived at its height, -which I suppose might be 3 or 400 Toises, it appeared to have only -horizontal Motion. I had a Pocket Glass, with which I follow’d it, -till I lost Sight first of the Men, then of the Car, and when I last -saw the Balloon, it appear’d no bigger than a Walnut. I write this at -7 in the evening. What became of them is not yet known here. I hope -they descended by Day-light, so as to see and avoid falling among -Trees or on Houses, and that the Experience was completed without any -mischievous Accident, which the Novelty of it & the want of Experience -might well occasion. I am the more anxious for the Event, because I am -not well informed of the Means provided for letting themselves gently -down, and the Loss of these very ingenious Men would not only be a -Discouragement to the Progress of the Art, but be a sensible Loss to -Science and Society. - -Tuesday Morning, December 2,—I am reliev’d from my Anxiety by hearing -that the Adventurers descended well near l’Isle Adam, before Sunset. -This Place is near 7 Leagues from Paris. Had the Wind blown fresh, they -might have gone much farther. - -P.S. Tuesday Evening ... I hear farther that the Travellers had perfect -Command of the Carriage, descending as they pleas’d by letting some of -the inflammable Air escape, and rising again by discharging some Sand; -that they descended over a Field so low as to talk with Labourers in -passing and mounted again to pass a Hill. The little Balloon falling at -Vincennes shows that mounting higher it met with a Current of Air in a -contrary Direction; an Observation that may be of use to future aërial -Voyagers. - - B. FRANKLIN. - - - - - APPENDIX III - - SUCCESSFUL MILITARY DIRIGIBLE BALLOONS - - FRANCE - - - _The Clément-Bayard II_[80] - -The _Clément-Bayard II_ may be classed among the airships usually -called “flexible.” The shape of its hull is preserved not by any rigid -framing, but by internal gas pressure maintained by ballonets fed by -ventilating fans. Moreover, the suspension which binds envelope and car -together as one solid is composed wholly of flexible elements, without -any rigid intermediary structure. - -The general plan, then, of the craft comprises three prominent -features, well marked and distinct in character: - -(_a_) The fish-shaped envelope with major section well forward, a form -favorable to both speed and stability. - -(_b_) The trussed girderlike car whose length allows the load to be -distributed over the hull, thus preserving its nicety of outline. -The most minute and technical and mechanical details were studied -for eighteen months by M. Clément and his devoted collaborator, the -engineer Sabathier. The girder car, as will be seen presently, is -particularly well designed to serve as car, sustainer and stiffener. No -stabilizing device is attached to the envelope; all are fixed to the -car, on which is mounted also the complete propulsion plant. - -(_c_) The suspension which binds the buoyant envelope to the car serves -no other purpose. Note also the ingenious arrangement of two motors -and two propellers, forming two independent systems, yet unitable -under certain conditions. The placement of the propellers, rudders and -stabilizing surfaces well above the bottom of the car, insures them -against dangerous contact on landing, or while maneuvering near the -ground. - -The envelope is of rubberized Continental cloth. Its volume is 7,000 -cubic meters, length 76.5 meters and major diameter 13.22 meters, or -an elongation of 5.76 diameters. Inside the gas envelope is an air bag -of 2,200 cubic meters. It is divided into two compartments, _Q_ and -_Q´_, which can be filled with air together or separately through the -air duct, _Q_, joined to a blower, _P_, run by the two motors, or by -hand when so desired. The balloon proper comprises two gas valves, _R_. -Each compartment of the ballonet has one air valve, _S_. The valves of -the type Clément-Bayard-Chauvière are automatic. Their construction is -so perfect that for the first time in France, at least on a balloon of -so large bulk, the blower runs continuously in constant communication -with the ballonet, the pressure in the envelope remaining invariable, -due to the regular play of the valves, which yield at the pressure for -which they are set. They may also be Worked by hand from the pilot’s -bridge in case of emergency. The envelope has on its upper side three -ripping seams, one in the middle, the others toward either end. These -rip panels can be worked together or separately, and permit the rapid -deflation of the balloon. - -The long car is attached to the hull by hempen duck feet fastened to -a bolt rope running along the envelope below the equator; these duck -feet terminate below in steel suspension cables fixed to the car. Below -the principal bolt rope are others to which are fastened the duck -feet of the oblique cords, which assure the perfect solidarity of the -envelope and car. The steel cable sustainers have an ingenious patented -regulating windlass. The girder car consists of a latticed girder, -built of steel tubes united with cast-iron joints and steel-tie wires. -Its whole length is 45 meters, of which 14.5 meters constitute the car -proper. It is divided into segments which are easily demountable, thus -rendering it easily transportable by truck or railway. The forward -segment, _A_, tapers toward the front to a sharp point and is of -triangular cross-section. The mid segment, _B_, constituting the car, -has a quadrangular section of variable size. The rear segment, _D_, is -of triangular section, diminishing progressively toward the rear, which -rises to a sort of tail supporting the empennage and the direction -rudders. The entire girder car when resting on the ground is supported -by two pneumatic shock absorbers, _U_, _U_, projecting from its floor. - -The car proper comprises three parts: in front, the motor and machine -room, 2.5 meters wide; in the middle, the elevated bridge, _N_, for -the pilot and his aide; in the rear, the passenger cabin, 8 meters -long, 1.3 meters wide and 2 meters high for the observers and wireless -telegraphy plant. The two reservoirs of essence, _M_, _m_, are placed -above the passenger about the center of pressure. The blower _P_, for -the ballonets, and the guide ropes _T_, are placed above the pilot’s -bridge. - -In the motor room are symmetrically arranged two Bayard-Clément -engines, _G G_, separated enough to allow free passage between them. -Each motor is elastically supported to obviate vibrations, and connects -with the transmission shaft by a variable speed gear. The engines -can be run separately or together by a connecting sprocket chain, and -develop 100 to 130 horse-power each. The cooling of each motor is -effected by an aluminum radiator, _L L_, of large surface. - -The Chauvière propellers, _K K_, six feet in diameter, are driven by -shafting and gear wheels at a normal speed of 250 rotations per minute. -A special recording device serves to show their thrust at each instant, -as also the torque of the motors. - -The pilot, standing on the bridge where he enjoys a clear view, has -immediate charge of the vessel’s movements. Before him are the various -controls which he must operate, and the divers indicators which he must -consult. These are the direction wheel, the manometers, the aneroid -and registering barometers, the clinometer, the blower control to -regulate the amount and distribution of pressure, the elevating-rudder -wheel, the spark control, the ripping cord, the release string of the -guide-rope, and the system of transmitting orders to the mechanicians -whereby he can control the engines and the blowers which furnish air to -the radiator and ballonet. - -The direction and poise of the vessel in flight are controlled by the -rudders and empennage at the rear, and its altitude from minute to -minute is governed by the elevating biplane _E´_, of 30 square meters -above the car in the mid region of the vessel. - - - The _Patrie_[81] - -The _Patrie_, the third of its type, was first operated in 1906. The -gas bag of the first balloon was built by Surcouf at Billancourt, -Paris. The mechanical part was built at the Lebaudy Sugar Refinery. -Since then the gas bags have been built at the Lebaudy balloon shed at -Moisson, near Paris, under the direction of their aëronaut, Juchmes. -The gas bag of the _Patrie_ was 197 feet long with a maximum diameter -of 33 feet, 9 inches, situated about 2/5 of the length from the front; -volume 111,250 cubic feet; length approximately six diameters. This -relation, together with the cigar shape, is in accordance with the -plans of Colonel Renard’s dirigible, built and operated in France in -1884; the same general shape and proportions being found in the Ville -de Paris. - -The first Lebaudy was pointed at the rear, which is generally admitted -to be the proper shape for the least resistance, but to maintain -stability it was found necessary to put a horizontal and vertical plane -there, so that it had to be made an ellipsoid of revolution to give -attachment for these planes. - -The ballonet for air had a capacity of 22,958 cubic feet or about 1/5 -of the total volume. This is calculated to permit reaching a height of -about one mile and to be able to return to the earth, keeping the gas -bag always rigid. To descend from a height of one mile, gas would be -released by the valve, then air pumped into the ballonet to keep the -gas bag rigid, these two operations being carried on alternately. On -reaching the ground from the height of one mile, the air would be at -the middle of the lower part of the gas bag and would not entirely fill -the ballonet. To prevent the air from rolling from one end to the other -when the air ship pitches, thus producing instability, the ballonet -was divided into three compartments by impermeable cloth partitions. -Numerous small holes were pierced in these partitions, through which -the air finally reached the two end compartments. - -In September, 1907, the _Patrie_ was enlarged by 17,660 cubic feet -by the addition of a cylindrical section at the maximum diameter, -increasing the length but not the maximum diameter. - -_The Gas Bag._—The gas bag is cut in panels; the material is a rubber -cloth made by the Continental Tire Company at Hanover, Germany. It -consists of four layers arranged as follows: - - Weight oz. per - square yard. - _a._ Outer layer of cotton cloth covered with lead chromate 2.5 - _b._ Layer of vulcanized rubber 2.5 - _c._ Layer of cotton cloth 2.5 - _d._ Inner layer of vulcanized rubber 2.21 - ------ - Total weight 9.71 - -A strip of this cloth one foot wide tears at a tension of about 934 -pounds. A pressure of about one inch of water can be maintained in the -gas bag without danger. The lead chromate on the outside is to prevent -the entrance of the actinic rays of the sun, which would cause the -rubber to deteriorate. The heavy layer of rubber is to prevent the -leaking of the gas. The inner layer of rubber is merely to prevent -deterioration of the cloth by impurities in the gas. This material -has the warp of the two layers of cotton cloth running in the same -direction and is called straight thread. The material in the ballonet -weighs only about 7¾ ounces per square yard, and has a strength of -about 336 pounds per running foot. When the _Patrie_ was enlarged in -September, 1907, the specifications of the material allowed a maximum -weight of 10 ounces per square yard, a minimum strength of 907 pounds -per running foot, and a loss of 5.1 cubic inches of hydrogen per square -yard in twenty-four hours at a pressure of 1.18 inches of water. Bands -of cloth are pasted over the seams inside and out with a solution of -rubber to prevent leaking through the stitches. - -_Suspension._—One of the characteristics of the _Patrie_ is the “short” -suspension. The weight of the car is distributed over only about 70 -feet of the length of the gas bag. To do this, an elliptical-shaped -frame of nickel-steel tubes is attached to the bottom of the gas -bag; steel cables run from this down to the car. A small hemp net -is attached to the gas bag by means of short wooden cross-pieces, -or toggles, which are let into holes in a strong canvas band which -is sewed directly on the gas bag. The metal frame, or platform, is -attached to this net by means of toggles, so that it can be quickly -removed in dismounting the air ship for transportation. The frame can -also be taken apart, 28 steel cables about 0.2 inches in diameter run -from the frame down to the car, and are arranged in triangles. Due -to the impossibility of deforming a triangle, rigidity is maintained -between the car and gas bag. - -The objection to the “short” suspension of the _Patrie_ is the -deformation of the gas bag. A distinct curve can be seen in the middle. - -_The Car._—The car is made of nickel-steel tubes (12 per cent nickel). -This metal gives the greatest strength for minimum weight. The car is -boat-shaped, about 16 feet long, about 5 feet wide and 2½ feet high. -About 11 feet separate the car from the gas bag. To prevent any chance -of the fire from the engine communicating with the hydrogen, the steel -framework under the gas bag is covered with a noncombustible material. - -The pilot stands at the front of the car, the engine is in the -middle, the engineer at the rear. Provision is made for mounting a -telephotographic apparatus, and for a 100-candle-power acetylene -searchlight. A strong pyramidal structure of steel is built under the -car, pointing downward. In landing the point comes to the ground first -and this protects the car, and especially the propellers, from being -damaged. The car is covered to reduce air resistance. It is so low, -however, that part of the equipment and most of the bodies of those -inside are exposed, so that the total resistance of the car is large. - -_The Motor._—The first Lebaudy had a 40-horse-power Daimler-Mercedes -benzine motor. The _Patrie_ was driven by a 60 to 70-horse-power -4-cylinder Panhard and Levassor benzine motor, making 1,000 r. p. m. - -_The Propellers._—There are two steel propellers 8½ feet in diameter -(two blades each) placed at each side of the engine, this giving the -shortest and most economical transmission. To avoid any tendency to -twist the car, the propellers turn in opposite directions. They are -“high speed,” making 1,000 to 1,200 r. p. m. - -The gasoline tank is placed under the car inside the pyramidal frame. -The gasoline is forced up to the motor by air compression. The exhaust -is under the rear of the car pointing down and is covered with a metal -gauze to prevent flames coming out. The fan which drives the air into -the ballonet is run by the motor, but a dynamo is also provided so -that the fan can always be kept running even if the motor stops. This -is very essential as the pressure must be maintained inside the gas -bag so that the latter will remain rigid and keep its form. There are -five valves in all, part automatic and part both automatic and also -controlled from the car with cords. The valves in the ballonet open -automatically at less pressure than the gas valves, so that when the -gas expands all the air is driven out of the ballonet before there is -any loss of gas. The ballonet valves open at a pressure of about O.78 -inches of water, the gas valves at about 2 inches. - -_Stability._—Vertical stability is maintained by means of fixed -horizontal planes. One having a surface of 150 square feet is attached -at the rear of the gas bag and due to its distance from the center of -gravity is very efficient. The elliptical frame attached under the gas -bag has an area of 1,055 square feet, but due to its proximity to the -center of gravity, has little effect on the stability. Just behind -the elliptical frame is an arrangement similar to the feathering of -an arrow. It consists of a horizontal plane of 150 square feet, and a -vertical plane of 113 square feet. To maintain horizontal stability, -that is, to enable the air ship to move forward in a straight line -without veering to the sides, fixed vertical planes are used. One runs -from the center to the rear of the elliptical frame and has an area of -108 square feet. - -In addition to the vertical surface of 113 square feet at the rear of -the elliptical frame, there is a fixed plane of 150 square feet at the -rear of the gas bag. To fasten the two perpendicular planes at the -rear of this gas bag, cloth flaps are sewed directly on the gas bag. -Nickel-steel tubes are placed in the flaps, which are then laced over -the tubes. With these tubes as a base, a light tube and wire framework -is attached and waterproof cloth laced on this framework. Additional -braces run from one surface to the other and from each surface to the -gas bag. The rudder is at the rear under the gas bag. It has about 150 -square feet and is balanced. - -A movable horizontal plane near the center of gravity, above the -car, is used to produce rising or descending motion, or to prevent -an involuntary rising or falling of the air ship due to expansion or -contraction of the gas or to other causes. After the adoption of this -movable horizontal plane, the loss of gas and ballast was reduced to a -minimum. Ballast is carried in 10- and 20-pound sandbags. A pipe runs -through the bottom of the car from which the ballast is thrown. - -There are two long guide-ropes, one attached at the front of the -elliptical frame and the other on the car. On landing, the one in front -is seized first so as to hold the air ship with the head to the wind. -The motor may then be stopped and the descent made by pulling down on -both guide-ropes. A heavy rope 22 feet long, weighing 110 pounds, is -attached at the end of a 164-foot guide-rope. This can be dropped out -on landing to prevent coming to the ground too rapidly. The equipment -of the car includes a “siren” speaking trumpet, carrier pigeons, iron -pins and a rope for anchoring the air ship, reserve supply of fuel and -water, and fire extinguisher. - -After being enlarged in September, 1907, the _Patrie_ made a number of -long trips at an altitude of 2,500 to 3,000 feet. In November, 1907, -she went from Paris to Verdun, near the German frontier, a distance of -about 175 miles, in about 7 hours, carrying four persons. This trip was -made in a light wind blowing from the northeast. Her course was east, -so that the wind was unfavorable. On Friday, November 20, 1907, during -a flight near Verdun, the motor stopped due to difficulty with the -carburetor. The air ship drifted with the wind to a village about 10 -miles away, where she was safely landed. The carburetor was repaired on -the 20th. Soon after, a strong wind came up and tore loose some of the -iron pickets with which it was anchored. This allowed the air ship to -swing broadside to the wind; it then tilted over on the side far enough -to let some of the ballast bags fall out. The 150 or 200 soldiers who -were holding the ropes were pulled along the ground until directed by -the officer in charge to let go. After being released, it rose and was -carried by the wind across the north of France, the English Channel -and into the north of Ireland. It struck the earth there, breaking off -one of the propellers, and then drifted to sea. - - - The _République_ - -This is the latest of the French military dirigible balloons, and -differs but slightly from its predecessor, the _Patrie_. The volume has -been increased by about 2,000 cubic feet. The length has been reduced -to 200 feet and the maximum diameter increased to 35½ feet. The shape -of the gas bag accounts for the 2,000 additional cubic feet of volume. -The motor and propeller are as in the _Patrie_. The total lifting -capacity is 9,000 pounds, of which 2,700 pounds are available for -passengers, fuel, ballast, instruments, etc. Its best performance was a -125-mile flight made in 6½ hours against an unfavorable wind. - -The material for the gas bag of the new air ship was furnished by the -Continental Tire Company. It is made up as follows: - - Weight oz. per - square yard. - Outer yellow cotton layer 3.25 - Layer of vulcanized rubber 3.25 - Layer of cotton cloth 3.25 - Inner layer of rubber 0.73 - ------ - Total weight 10.48 - -It is interesting to note the changes which this type has undergone -since the first one was built. The _Jaune_, constructed in 1902-3, was -pointed at the rear and had no stability plane there; later it was -rounded off at the rear and a fixed horizontal plane attached. Finally -a fixed vertical plane was added. The gas bag has been increased in -capacity from 80,670 cubic feet to about 131,000 cubic feet. The -manufacturers have been able to increase the strength of the material -of which the gas bag is made, without materially increasing the weight. -The rudder has been altered somewhat in form. It was first pivoted on -its front edge, but later on a vertical axis, somewhat to the rear of -this edge. With the increase in size, has come an increase in carrying -capacity and, consequently, a greater speed and more widely extended -field of action. - - - _Ville de Paris_ - -This air ship was constructed for Mr. Deutsch de la Meurthe, of -Paris, who has done a great deal to encourage aërial navigation. The -first _Ville de Paris_ was built in 1902, on plans drawn by Tatin, -a French aëronautical engineer. It was not a success. Its successor -was built in 1906, on plans of Surcouf, an aëronautical engineer and -balloon builder. The gas bag was built at his works in Billancourt, -the mechanical part at the Voisin shop, also in Billancourt. The plans -are based on those of Colonel Renard’s air ship, the _France_, built -in 1884, and the _Ville de Paris_ resembles the older air ship in many -particulars. In September, 1907, Mr. Deutsch offered the use of his air -ship to the French Government. The offer was accepted, but delivery was -not to be made except in case of war or emergency. When the _Patrie_ -was lost in November, 1907, the military authorities immediately took -over the Deutsch air ship. - -_Gas Bag._—The gas bag is 200 feet long for a maximum diameter of 34½ -feet, giving a length of about 6 diameters, as in the _France_ and -the _Patrie_. Volume, 112,847 cubic feet; maximum diameter at about -⅜ of the distance from the front, approximately, as in the _Patrie_. -The middle section is cylindrical with conical sections in front -and rear. At the extreme rear is a cylindrical section with eight -smaller cylinders attached to it. The ballonet has a volume of 21,192 -cubic feet or about ⅕ of the volume, the same proportion found in -the _Patrie_. The ballonet is divided into three compartments from -front to rear. The division walls are of permeable cloth, and are not -fastened to the bottom so that when the middle compartment fills with -air, and the ballonet rises, the division walls are lifted up from -the bottom of the gas bag, and there is free communication between -the three compartments. The gas bag is made up of a series of strips -of perpendicular to a meridian line. These strips run around the -bag, their ends meeting on the under meridian. This is known as the -“barchistode” method of cutting out the material, and has the advantage -of bringing the seams parallel to the line of greatest tension. They -are therefore more likely to remain tight and not allow the escape -of gas. The disadvantage lies in the fact that there is a loss of -33⅓ per cent of material in cutting. The material was furnished by -the Continental Tire Company, and has approximately the same tensile -strength and weight as that used in the _Patrie_. It differs from the -other in one important feature—it is diagonal thread, that is, the warp -of the outer layer of cotton cloth makes an angle of 45 degrees with -the warp of the inner layer of cotton cloth. The result is to localize -a rip or tear in the material. A tear in the straight thread material -will continue along the warp, or the weave, until it reaches a seam. - -_Valves._—There are five in all, made of steel, about fourteen inches -in diameter; one on the top connected to the car by a cord, operated by -hand only; two near the rear underneath. These are automatic but can -be operated by hand from the car. Two ballonet valves directly under -the middle are automatic and are also operated from the car by hand. -The ballonet valves open automatically at a pressure of 2/3 inches of -water; the gas valves open at a higher pressure. - -_Suspension._—This air ship has the “long” suspension. That is, the -weight is distributed along practically the entire length of the gas -bag. A doubled band of heavy canvas is sewn with six rows of stitches -along the side of the gas bag. Hemp ropes running into steel cables -transmit most of the weight of the car to these two canvas bands and -thus to the gas bag. On both sides and below these first bands are -two more. Lines run from these to points half way between the gas -bag and the car, then radiate from these points to different points -of attachment on the car. This gives the triangular or nondeformable -system of suspension, which is necessary in order to have the car and -gas bag rigidly attached to each other. With this “long” suspension, -the _Ville de Paris_ does not have the deformation so noticeable in the -gas bag of the _Patrie_. - -_The Car._—This is in the form of a trestle. It is built of wood with -aluminum joints and O.12 inch wire tension members. It is 115 feet -long, nearly 7 feet high at the middle and a little over 5½ feet wide -at the middle. It weighs 660 pounds and is considered unnecessarily -large and heavy. The engine and engineer are well to the front, the -aëronaut with steering wheels is about at the center of gravity. - -_Motor._—The motor is a 70 to 75-horse-power _Argus_, and is -exceptionally heavy. - -_Propeller._—The propeller is placed at the front end of the car. It -thus has the advantage of working in undisturbed air; the disadvantage -is the long transmission and difficulty in attaching the propeller -rigidly. It has two blades and is 19.68 feet long with a pitch of -26.24 feet. The blades are of cedar with a steel arm. The propeller -makes a maximum of 250 turns per minute when the engine is making 900 -revolutions. Its great diameter and width compensate for its small -speed. - -_Stability._—This is maintained entirely by the cylinders at the rear. -Counting the larger one to which the smaller ones are attached, there -are five, arranged side by side corresponding to the horizontal planes -of the _Patrie_, and five vertical ones corresponding to the _Patrie’s_ -vertical planes. The volume of the small cylinders is so calculated -that the gas in them is just sufficient to lift their weight, so they -neither increase nor decrease the ascensional force of the whole. The -horizontal projection of these cylinders is 1,076 square feet. The -center of this projection is 72 feet from the center of gravity of the -gas. The great objection to this method of obtaining stability, is the -air resistance due to these cylinders, and consequent loss of speed. -The stability of the _Ville de Paris_ in a vertical plane is said to be -superior to that of the _Patrie_, due to the fact that the stability -planes of the latter do not always remain rigid. The independent -velocity of the _Ville de Paris_ probably never exceeded 25 miles an -hour. - -_The Rudder._—The rudder has a double surface of 150 square feet placed -at the rear end of the car, 72 feet from the center of gravity. It is -not balanced, but is inclined slightly to the rear so that its weight -would make it point directly to the rear if the steering gear should -break. Two pairs of movable horizontal planes, one at the rear of the -car having 43 square feet, and one at the center of gravity (as on the -_Patrie_) having 86 square feet, serve to drive the air ship up or down -without losing gas or ballast. - -_Guide-Ropes._—A 400-foot guide-rope is attached at the front end of -the car. A 230-foot guide-rope is attached to the car at the center of -gravity. - -About thirty men are required to maneuver the _Ville de Paris_ on the -ground. The pilot has three steering wheels, one for the rudder and -two for the movable horizontal planes. The instruments used are an -aneroid barometer, a registering barometer giving heights up to 1,600 -feet, and an ordinary dynamometer, which can be connected either with -the gas bag or ballonet by turning a valve. A double column of water -is also connected to the tube to act as a check on the dynamometer. -Due to the vibration of the car caused by the motor, these instruments -are suspended by rubber attachments. Even with this arrangement, it is -necessary to steady the aneroid barometer with the hand in order to -read it. The vibration prevents the use of the statoscope. - - - GERMANY - -Three different types of air ships are being developed in Germany. The -_Gross_ is the design of Major Von Gross, who commands the Balloon -Battalion at Tegel near Berlin. The _Parseval_ is being developed by -Major Von Parseval, a retired German officer, and the _Zeppelin_ is the -design of Count Zeppelin, also a retired officer of the German Army. - - - The _Gross_ - -The first air ship of this type made its first ascension on July 23, -1907. The mechanical part was built at Siemen’s Electrical Works in -Berlin; the gas bag by the Riedinger firm in Augsburg. - -_Gas Bag._—The gas bag is made of rubber cloth furnished by the -Continental Tire Company similar to that used in the _Ville de Paris_. -It is diagonal-thread, but there is no inner layer of rubber, as they -do not fear damage from impurities in the hydrogen gas. Length, 131¼ -feet; maximum diameter about 39⅓ feet; volume, 63,576 cubic feet; the -elongation is about 3⅓. The form is cylindrical with spherical cones at -the ends, the whole being symmetrical. - -_Suspension._—The suspension is practically the same as that of the -_Patrie_. A steel and aluminum frame is attached to the lower part of -the gas bag, and the car is suspended on this by steel cables. The -objection to this system is even more apparent in the _Gross_ than in -the _Patrie_. A marked dip along the upper meridian of the gas bag -shows plainly the deformation. - -_The Car._—The car is boat-shaped like that of the _Patrie_. It is -suspended thirteen feet below the gas bag. - -_Motor._—The motor is a 20- to 24-horse-power, 4-cylinder -Daimler-Mercedes. - -_Propellers._—There are two propellers 8³/₁₀ foot in diameter, each -having two blades. They are placed one on each side, but well up under -the gas bag near the center of resistance. The transmission is by belt. -The propellers make 800 r. p. m. - -_Stability._—The same system, with planes, is used in the _Gross_ as -in the _Patrie_, but it is not nearly so well developed. At the rear -of the rigid frame, attached to the gas bag, are two fixed horizontal -planes, one on each side. A fixed vertical plane runs down from between -these horizontal planes, and is terminated at the rear by the rudder. -A fixed horizontal plane is attached on the rear of the bags as in the -_Patrie_. The method of attachment is the same, but the plane is put on -before inflation in the _Gross_ air ship, afterwards in the _Patrie_. -The stability of the _Gross_ air ship in a vertical plane is reported -to be very good, but it is said to veer considerably in attempting to -steer a straight course. - -The many points of resemblance between this dirigible and the Lebaudy -type are worthy of notice. The suspension or means of maintaining -stability, and the disposition for driving are in general the same. As -first built, the _Gross_ had a volume of 14,128 cubic feet less than -at present, and there was no horizontal plane at the rear of the gas -bag. Its maximum speed is probably fifteen miles per hour. As a result -of his experiments of 1907, Major Von Gross has this year produced a -perfected air ship, built on the same lines as his first, but with -greatly increased volume and dimensions. The latest one has a volume of -176,000 cubic feet, is driven by two 75-horse-power Daimler motors, and -has a speed of 27 miles per hour. - -On September 11th of this year, the _Gross_ air ship left Berlin at -10.25 P.M., carrying four passengers, and returned the next day at -11.30 A.M., having covered 176 miles in the period of a little over 13 -hours. This is the longest trip, both in point of time and distance, -ever made by any air ship returning to the starting point. - - - The _Parseval_ - -The _Parseval_ air ship is owned and controlled by the Society for the -Study of Motor Balloons. This organization, composed of capitalists, -was formed practically at the command of the emperor, who is very much -interested in aërial navigation. The society has a capital of 1,000,000 -marks, owns the _Parseval_ patents and is ready to construct air ships -of the _Von Parseval_ type. The present air ship was constructed by the -Riedinger firm at Augsburg, and is operated from the balloon house of -this society at Tegel, adjoining the military balloon house. - -The gas bag is similar in construction to that of the _Drachen_ -balloon, used by the army for captive work. Volume, 113,000 cubic -feet; length, 190 feet; maximum diameter, 30½ feet. It is cylindrical -in shape, rounded at the front and pointed at the rear. The material -was furnished by the Continental Tire Company. It is diagonal-thread, -weighing about 11³/₁₀ ounces per square yard and having a strength of -about 940 pounds per running foot. Its inner surface is covered with a -layer of rubber. - -_Ballonets._—There are two ballonets, one at each end, each having a -capacity of 10,596 cubic feet. The material in the ballonet weighs -about 8¼ ounces per square yard, the cotton layers being lighter than -in the material for the gas bag. Air is pumped into the rear ballonet -before leaving the ground, so that the air ship operates with the front -end inclined upward. The air striking underneath exerts an upward -pressure, as on an aëroplane, and thus adds to its lifting capacity. -Air is pumped into the ballonets from a fan operated by the motor. -A complex valve, just under the middle of the gas bag, enables the -engineer to drive air into either, or both ballonets. The valves also -act automatically and release air from the ballonets at a pressure of -about 0.9 inches of water. - -In the middle of the top of the gas bag is a valve for releasing the -gas. It can be operated from the car, and open automatically at a -pressure of about 2 inches of water. Near the two ends and on opposite -sides are two rip strips controlled from the car by the cords. - -_Suspension._—The suspension is one of the characteristics of the air -ships, and is protected by patents. The car has four trolleys, two on -each side, which run on two steel cables. The car can run backwards -and forwards on these cables, thus changing its position with relation -to the gas bag. This is called “loose” suspension. Its object is to -allow the car to take up, automatically, variations in thrust due to -the motor, and variations in resistance due to the air. Ramifications -of hemp rope from these steel cables are sewed onto a canvas strip, -which in turn is sewed onto the gas bag. This part of the suspension is -the same as in the _Drachen_ balloon. The weight is distributed over -the entire length of the gas bag. - -_The Car._—The car is 16.4 feet long and is built of steel tubes and -wire. It is large enough to hold the motor and three men, though four -or five may be taken. - -_Motor._—The motor is a 110-horse-power Daimler-Mercedes. Sufficient -gasoline is carried for a run of twelve hours. - -_Propeller._—The propeller, like the suspension, is peculiar to this -air ship and is protected by patents. It has four cloth blades which -hang limp when not turning. When the motor is running, these blades, -which are carefully weighed with lead at certain points, assume the -proper position due to the various forces acting. The diameter is 13¾ -feet. The propeller is placed above the rear of the car near the center -of resistance. Shaft transmission is used. The propeller makes 500 -r. p. m. to 1,000 of the motor. There is a space of 6½ feet from the -propeller blades to the gas bag, the bottom of the car being about 30 -feet from the gas bag. This propeller has the advantage of being very -light. Its position, so far from the engine, necessarily incurs a great -loss of power in transmission. - -The steering wheel at the front of the car has a spring device for -locking it in any position. - -The 1908 model No. 1 of this air ship was constructed for the purpose -of selling it to the government. Among other requirements is a 12-hour -flight without landing, and a sufficient speed to maneuver against a -22-mile wind. A third and larger air ship of this type is now under -construction. - - - UNITED STATES - - _Signal Corps Dirigible No. 1_ - -Due to the lack of funds, the United States Government has not been -able to undertake the construction of an air ship sufficiently large -and powerful to compete with those of European nations. However, -specifications were sent out last January for an air ship not over 120 -feet long and capable of making 20 miles per hour. Contract was awarded -to Capt. Thomas S. Baldwin, who delivered an air ship last August to -the Signal Corps, the description of which follows: - -_Gas Bag._—The gas bag is spindle shaped, 96 feet long, maximum -diameter, 19 feet 6 inches, with a volume of 20,000 cubic feet. A -ballonet for air is provided inside the gas bag, and has a volume of -2,800 cubic feet. The material for the gas bag is made of two layers of -Japanese silk, with a layer of vulcanized rubber between. - -_Car._—The car is made of spruce, and is 66 feet long, 2½ feet wide and -2½ feet high. - -_Motor._—The motor is a 20-horse-power water-cooled Curtiss make. - -_Propeller._—The propeller is at the front end of the car, and is -connected to the engine by a steel shaft. It is built of spruce, has -a diameter of 10 feet, 8 inches, with a pitch of 11 feet, and turns -at the rate of 450 r. p. m. A fixed vertical surface is provided at -the rear end of the car to minimize veering, and a horizontal surface -attached to the vertical rudder at the rear tends to minimize pitching. -A double horizontal surface controlled by a lever and attached to the -car in front of the engine, serves to control the vertical motion and -also to minimize pitching. - -The position of the car very near to the gas bag, is one of the -features of the Government dirigible. This reduces the length and -consequently the resistance of the suspension, and places the propeller -thrust near the center of resistance. - -The total lifting power of the air ship is 1,350 pounds of which -500 pounds are available for passengers, ballast, fuel, etc. At its -official trials a speed of 19.61 miles per hour was attained over a -measured course and an endurance run lasting two hours, during which -seventy per cent of the maximum speed was maintained. - -_Dirigible No. 1_, as this air ship has been named, has already served -a very important purpose in initiating officers of the Signal Corps -in the construction and operation of a dirigible balloon. With the -experience now acquired, the United States Government is in a position -to proceed with the construction and operation of an air ship worthy of -comparison with any now in existence, but any efforts in this direction -must await the action of Congress in providing the necessary funds. - - - - - APPENDIX IV - - THE RELATIONS OF WEIGHT, SPEED AND POWER OF FLYERS[82] - - _By Wilbur and Orville Wright_ - - -The flyer of 1903 carried a four-cylinder gasoline motor of four-inch -bore and four-inch stroke. Complete with magneto, radiators, tanks, -water, fuel, etc., the motor weighed a little over 200 pounds, and at -1,200 revolutions per minute developed 16 horse power for the first 15 -seconds after starting. After a minute or two the power did not exceed -13 or 14 horse power. At 1,020 revolutions per minute—the speed of the -motor in the flights at Kitty Hawk on the 17th of December, 1903—it -developed about 12 horse power. - -The flyer of 1904 was equipped with a motor similar to the first, but -of 1/8-inch larger bore. This engine at 1,500 revolutions per minute -developed 24 horse power for the first 15 seconds, but only 16 to 17 -horse power after a few minutes run. Complete with water, fuel and -other accessories, it weighed 240 pounds. - -The same engine with a few modifications in the oiling device and the -carburetor, was used in all the flights of 1905. A test of its power -made soon after the flights of October, 1905, revealed a gain of 3 -horse power over tests made just before mounting it on the flyer -in 1904. This gain is attributed to the increased smoothness of the -cylinders and pistons produced by wear. The small output of these -engines was due to lack of experience in building gasoline motors. - -During the past year further improvements have been made, and our -latest engines of four-inch bore and four-inch stroke produce about 25 -horse power continuously. The improvement in the reliability of the -motor has been even more marked, so that now flights of long distances -can be attempted without danger of failure on account of the stopping -of the motor. - -A comparison of the flyers of 1903, 1904 and 1905 show some interesting -facts. The flyer of 1903 weighed, complete with operator, 745 pounds. -Its longest flight was of 59 seconds duration, with a speed of 30 miles -an hour and an expenditure of 12 horse power. The flyer of 1904 weighed -about 900 pounds, including a load of 70 pounds in iron bars. A speed -of more than 34 miles an hour was maintained for a distance of three -miles with an expenditure of 17 horse power. The flyer of 1905 weighed, -including load, 925 pounds. With an expenditure of 19 to 20 horse power -it traveled over 24 miles at a speed of more than 38 miles an hour. The -flights of 1904 and 1905 would have been slightly faster had they been -made in a straight line, as were those of 1903. - -In 1903, 62 pounds per horse power were carried at a speed of 30 miles -an hour; in 1904, 53 pounds, at 34 miles an hour; and in 1905, 46 -pounds at 38 miles an hour. It will be noted that the weight carried -per horse power is almost exactly in inverse ratio to the speed, as -theory demands—the higher the speed, the smaller the weight carried per -horse power. - -Since flyers can be built with approximately the same dynamic -efficiency for all speeds up to 60 miles an hour, a flyer designed to -carry a total weight of 745 pounds at 20 miles an hour would require -only 8 horse power or two thirds of the power necessary for 30 miles an -hour. At 60 miles 24 horse power would be necessary—twice that required -to carry the same weight at 30 miles an hour. At 120 miles an hour 60 -to 75 horse power would probably be necessary, and the weight carried -per horse power would be only 10 or 12 pounds. At such high speed -the resistance of the operator’s body and the engine is a formidable -factor, consuming 64 times as much horse power as at 30 miles an hour. -At speeds below 60 miles an hour this resistance is almost negligible. - -It is evident that the limits of speed have not as yet been closely -approached in the flyers already built, and that in the matter of -distance, the possibilities are even more encouraging. Even in the -existing state of the art it is easy to design a practical and durable -flyer that will carry an operator and supplies of fuel for a flight of -over 500 miles at a speed of 50 miles an hour. - - - - - APPENDIX V - - CURTISS’S EXPERIMENTS IN RISING FROM THE WATER[83] - - -During the past two years Glenn H. Curtiss, who, more than any other -experimenter, has been given to developing the aëroplane for various -uses, has experimented with floats for his biplane that would enable -it to rise from the surface of the water. Something over a year ago he -succeeded in developing a speed of about twenty miles an hour on the -water, but this was insufficient to rise from the surface. - -At the beginning of the new year Mr. Curtiss moved to the Pacific Coast -and set about endeavoring to develop suitable floats which would make -it possible for his machine to rise from the surface of the water. -These experiments have been carried on at San Diego, where Mr. Curtiss -is instructing several naval and military officers in the art of flying. - -In his first experiments on the Pacific Coast Mr. Curtiss followed -the successful experiments of this sort made by M. Henri Fabre at -Marseilles, France, about a year ago, as far as the design of his -floats was concerned. He constructed one large float six feet wide, -five feet from front to rear, and one foot thick at its central point, -and placed this under the center of the machine. The bottom of this -float was perfectly flat and arranged at an incline of ten or twelve -degrees. Some distance forward of the main float, at about the position -of the front wheel in the land machine, another float six feet wide, -by one foot from front to rear, and six inches deep, was placed; while -at the extreme front end of the machine, on a special outrigger, was -mounted a small elevating hydroplane six feet wide by eight inches -in a fore-and-aft direction, and one and one-half inches thick. This -hydroplane was fixed at an angle of about twenty-five degrees and was -intended to lift the front part of the machine. A spray shield was -fitted back of it, as shown in the diagram, page 333. - -The first experiments were made with these new floats on January 26th -last; and although they made a considerable disturbance in the water, -especially at low speed, the aviator was enabled to get up a speed on -the surface of about forty-five miles an hour. He found that at as low -a rate as ten miles the hydroplanes (which normally were submerged) -rose to the surface, while as the speed increased only the rear edges -of the two main planes were required to support the machine. The -aëroplane readily attained sufficient speed to rise in the air, for -as the speed increased and the floats emerged from the water, the -head resistance of the floats diminished and there was only the skin -friction of the water on a few inches of the rear edge of these floats, -plus the air resistance, to be overcome. - -At the first try-out, while traveling over the water at high speed, -Mr. Curtiss found himself suddenly nearing the shore, and to avoid -running aground he turned his horizontal rudder sharply upward, with -the result that the machine rose from the water with perfect ease. -He soon alighted again, and in the second flight he made a circle -and remained in the air a minute and twenty-one seconds. Two other -experimental flights were made the first day, and on January 27th he -made a three-and-one-half-minute flight and stated, upon alighting, -that he found no difficulty in remaining aloft as long as he pleased. -The machine showed a speed of fifty miles an hour in the air as against -forty-five miles an hour when skimming over the surface of the water. - -PLATE XXXII. - -[Illustration: CURTISS STARTING FROM THE WATER.] - -[Illustration: CURTISS BIPLANE FOR LAND AND WATER.] - -[Illustration: CURTISS TRIPLANE RISEN FROM THE WATER.] - -Not satisfied with the several floats with which he had attained -his first success in rising from the water, Mr. Curtiss immediately -constructed a single float twelve feet long by two feet in width -and twelve inches deep. This float is built of wood and resembles a -flat-bottomed boat or scow, the top being covered with canvas to keep -the water from getting in. Three feet from the front end the bottom -is curved upward forming a bow the full width of the float, while at -the same distance from the rear the float slants downward in a similar -manner. - -This single float is placed under the aëroplane in such a position that -the main weight of the machine and aviator is slightly to the rear of -the center of the float, which causes the latter to incline upward -slightly and thus gives the necessary angle for hydroplaning on the -surface of the water. The weight of this new float is but fifty pounds, -or less than half as much as that of the two floats that were used -before. - -The paint was barely dry on the new float before Mr. Curtiss had it -fitted to his machine and gave it a trial. This was done on February -1st and the trial was thoroughly successful. The machine ran over the -surface of the water with very much less disturbance than before and -rose in the air readily. A glance at the photographs showing the new -and the old floats in action will give one an excellent idea of the -much less commotion caused by the single scow-shaped float. Besides -being much more compact and creating less disturbance, this float or -scow can be used for carrying articles or a passenger. - -In order to keep the aëroplane from tilting to one side or the other, -an inclined stick four feet long and three inches wide, to which is -attached on its upper side an inflated rubber tube, is fastened to the -front edge of the lower plane at each end. By the use of these props -the aëroplane does not tip readily when skimming along the surface, -even though the scow-shaped float used is but two feet in width. - -After meeting with success with his new float, Mr. Curtiss, on February -17th, made more flights with the motor and propeller placed at the -front of his biplane and with his seat placed at the rear of the main -planes. The chief of these flights was one which he made from North -Island, where he is experimenting, over San Diego harbor to the cruiser -_Pennsylvania_. He alighted upon the surface close beside the cruiser -and his aëroplane was hauled up beside the warship and placed on her -deck. - -After a short visit on the cruiser the aviator was again lowered to the -surface in his machine. A sailor started the engine, and Mr. Curtiss -flew back to his starting point in short order. The naval authorities -were greatly pleased with his demonstration and it is probable that the -Navy Department will purchase one of these machines in the near future -and continue the instruction of its officers. - -After increasing the surface of his biplane Mr. Curtiss, on February -24th, took up one of his naval pupils, Lieutenant T. G. Ellyson, as -a passenger. He made a flight of one and one-half miles, rising to a -height of one hundred feet and flying as slowly as twenty-five miles an -hour, or as fast as fifty miles an hour, at will. Lieutenant Ellyson -was seated on the pontoon below the aëroplane. He could look down -in the water and see bottom at a depth of twenty-five feet, and he -believes submarines can be easily located by flying over the water. -The slow speed at which it is possible to fly will make the biplane -especially useful for bomb dropping. As we go to press Mr. Curtiss is -about to try his machine fitted with wheels and floats as well. - - - - - INDEX - - - Abbe, Cleveland, 200, 437. - - Acosta, 10. - - Ader, C. F., 222-226. - - Aërial Experiment Association, 264-267, 305. - - Aëro Club of America, 243, 244, 322, 323. - of France, 106, 256, 258, 259, 301. - of Great Britain, 287. - - Aëro Corporation Limited, 322. - - Aërodrome, 111, 194, 240, 292. - - Aëronat, 126. - - Aëronautic meteorology, 347 _et seq._ - - Aëronautic Society of New York, 284. - - _Aëronautical Annual_, 215, 227, 427. - - _Aëronautics_, 252. - - _Aërophile_, 130, 166, 340. - - Aëroplanes, Ader’s, 222-226. - advances in, in 1909, 283, 284. - Aërial Experiment Association’s, 264-267. - _Antoinette_, 288, 289, 320, 324. - Blériot’s, 267-270, 286, 287, 290-292, 299, 300, 309. - Bréguet’s, 313. - Chanute and Herring’s, 218-221. - Cody’s, 305. - competitive flying of, 283 _et seq._ - cost of, 342. - Curtiss’, 264-266, 284-286, 294-300, 316, 317, 322, 333. - Delagrange’s flights with, 261-263. - _Demoiselle_, 324. - Deperdussin’s, 399. - earliest public flight of, 257. - Esnault-Pélterie’s, 304, 314, 337. - Etrich’s, 335, 336. - Fabre’s, 332, 335. - Farman’s, Henri, 259-264, 298, 303, 305, 321. - Farman’s, Maurice, 305, 311. - first tour in, 268-270. - first town-to-town flight in, 264. - Grade’s, 304. - Hanriot’s, 339. - Herring’s compressed air, 221, 222. - impossibility of, 12. - Langley’s, 239-243. - launching of, 202. - Le Bris’, 203-205. - Lilienthal’s, 207-209. - Mattullath’s, 235-239. - Maxim’s, 226-228. - model, 173 _et seq._ - Montgomery’s, 251-255, 282. - Mouillard’s, 207-209. - Nieuport’s, 339. - nineteenth century, 202 _et seq._ - Paulhan’s, 324, 325. - Pilcher’s, 216-218. - public flying, 256 _et seq._ - reliability of, 341. - Santos-Dumont’s, 256-258, 303, 324. - stability of, 232-234. - stable and powerful, 235 _et seq._ - Tellier’s, 312. - utility of, 341. - Voisin’s, 259, 267, 313. - Wright brothers’, 245-249, 270-282, 309, 324, 326, 329. - Zahm’s system of control of, 229-231. - - Aërostal, 22. - - Æschylus, 29. - - Agobard, 22. - - Ailerons, 286. - - Air bag, 83. - - Air friction, 238, 239. - - Airscout, 11, 12. - - Allen, Gen. James, 271. - - Alps, Chavez’s flight across, 318, 319. - - Altitude records, 307-309. - - _American Engineer and Railway Journal_, 229. - - American military dirigible, 138. - - _Antoinette_ monoplane, 288, 289, 309, 320, 324, 340. - - Archdeacon, Ernest, 256. - - Archibald, Douglass, 77. - - Archytas of Tarentum, 198. - - Arlandes, Marquis de, 38-42. - - Ascending trend of wind, 211. - - Assman, Professor, 72. - - Astra Society, 120, 123, 124. - - Atmosphere, composition of, 348-350. - cyclones, tornadoes, waterspouts, 394 _et seq._ - general circulation of, 376-380. - general properties of, 347 _et seq._ - permanent and periodic winds, 376 _et seq._ - temperature and pressure, 363 _et seq._ - thunderstorms, windgusts, 422 _et seq._ - - Aubrun, Emile, 331. - - Audemars, 324. - - Automobile Club of France, 321. - - - Bacon, Roger, 20. - - Balance, complete dynamical, 234. - - Baldwin, F. W., 264, 266. - Thomas S., 138. - - Ballonets, 95. - - _Ballons sondes_, 72. - - Balloon, dirigible: - Baumgarten and Wölfert’s, 99. - _Belgique_, 129. - Blanchard’s, 79, 80. - British and American, 130, 131. - _Clément-Bayard I_, 123. - _Clément-Bayard II_, 131, 132, 133. - combined with aëroplane, 123. - _Colonel Renard_, 124, 126. - development of rigid, 145 _et seq._ - Dupuy de Lome’s, 19, 92, 93. - early experiments with Zeppelin, 147-150. - early gasoline driven, 10 _et seq._ - electric, 92-97. - _España_, 124, 126, 127. - first designs for, 78-86. - general design of _Zeppelin_, 146, 147. - German aërial fleet, 141, 142. - German nonrigid, 138. - Giffard’s, 90, 91, 98. - Gross type of, 138, 139, 140, 471-473. - Hänlein’s, 98. - Hopkinson’s suggestion for, 84. - Italian, 130. - _Jaune_, 115, 116. - Jefferson’s suggestion for, 84. - Jullien’s model, 88. - _Lebaudy_, 116, 117. - Lebaudy’s, 115-120, 134-137. - _Liberté_, 120. - maneuvers at Cologne, 143, 144. - Meusnier’s designs for, 85, 86. - Miolan and Janinet’s, 81. - _Morning Post_, 134. - muscular driven, 80, 82, 85, 92. - Parseval type of, 138, 139, 140-143, 473-476. - _Patrie_, 115, 118, 119. - Porter’s, 86, 87. - practical development of nonrigid, 115 _et seq._ - practical speed of, 101. - Renard and Krebs’, 93-97. - _Republique_, 115, 118, 119, 466. - Robert’s, 81, 82, 83. - _Russie_, 120. - Santos-Dumont’s, 102-114. - Schwartz’s, 99, 100. - steam, 87, 89. - successful military, 456. - two systems of, 101. - types of, 122. - _U. S. Military I_, 138, 476, 477. - _Ville de Nancy_, 124, 125. - _Ville de Paris_, 120-123, 467-471. - voyage of across English channel, 132, 136, 137. - in _Zeppelin_, 153-156. - _Zeppelin IV_, explosion, 157, 158. - _Zeppelin_ passenger service, 167-169. - _Zeppelin_ type of, 145-169. - _Zodiac_ type of, 127, 128, 129. - passive: - cabinet for lofty ascents in, 71, 72. - Charles’ passenger, 42, 43. - cruise of, from London to Weilburg, 54. - dragon fire-inflated, 20. - earliest conceptions of, 18, 29. - earliest experiments with, 30, 31, 32. - early history of, 29 _et seq._ - first coal gas, 54. - first human passengers in, 38. - first hydrogen, 35. - first passengers in, 37. - first scientific ascension in, 44, 45. - Glashier’s observations in, 64-70. - highest ascent of, 69, 70, 71, 72. - instruments and adjuncts to, 76, 77. - largest hot air, 48-50. - largest gas, 70, 71. - longest voyage of, 74. - modern spherical, 75. - Nadar’s _Geant_, 60, 61. - practical development of, 54 _et seq_. - principle of, 18. - public inauguration of, 33, 34. - recent improvements in, 76, 77. - ripping panel of, 74, 75. - sounding and pilot, 72. - voyage across the Atlantic in, 74, 75. - across the English channel in, 50, 52. - Paris to Meaux in, 61, 62. - Paris to Nienburg in, 62, 63. - - Balsan, 74. - - Baltimore aviation meet, 319. - - _Baltimore Sun_, 319. - - Barometric pressure, 363 _et seq._ - distribution of, 370-374. - gradient of, 370. - high and low areas of, 372. - hygrometric features of, 373. - mechanical features of, 373, 374. - modifying conditions of, 371, 373. - surfaces and lines of equal, 370, 371. - - Basenach, 138. - - Baumgarten, 99. - - _Belgique_, the, 129. - - Bell, A. G., 194, 244, 264-267. - - Bell, Mrs. A. G., 264. - - Belmont Park, 310, 322. - - Bennett international contests, 75, 292-301, 325, 326. - - Berson, Professor, 70. - - Betheny Plain, 292. - - Bielovucic, Jean, 313. - - Bigelow, Professor, 412, 413. - - Biplane, 174, 220. - - Birds, armed against airships, 11. - as men carriers, 10, 11, 12. - major limit of, 11, 12. - - Bishop, Cortlandt Field, 285. - - Black, 29. - - Blanchard, 15, 16, 18, 50, 79, 80. - - Blériot, Louis, 267-270, 286, 287, 290-292, 299-300, 380-382. - - Bréguet, Louis, 313. - - Brookins, Walter, 309, 326. - - Brown, D. S., 193. - - Bubbles, soap and varnish, 30. - - - Calm belts, 381. - - Cammerman, Lieutenant, 314. - - Cardan, 10. - - Catapult, 240, 338. - - Cavallo, 30, 31. - - Cavendish, 29. - - Cayley, Sir George, 181, 182. - - Chanute, Octave, 15, 181, 218-221, 245, 250, 256, 260. - - Charles, 35. - - _Charlière_, 42. - - _Chauvière_, 125, 136, 331, 339. - - Chavez, George, 318, 319. - - _Circuit de l’Est_, 339, 331. - - _Clément-Bayard_, the, 123, 131-133, 456-459. - - Cody, S. F., 305. - - _Colonel Renard_, the, 124, 126. - - _Compagnie General Transaerienne_, 124. - - Control, three rudder system of, 229-331. - - Coulomb, 17, 18. - - _Country Life_, 321. - - Coxwell, 64-70. - - Critical temperature and pressure, 351. - - Cross-country records, 311-314. - - Curtiss, Glenn H., 138, 264-266, 282, 284-286, 294-300, 316, 317, - 322, 323, 481 _et seq._ - - Cyclone, frequency of, 403, 404. - motions and pressures in, 395, 400. - motive power of, 395. - nature of, 394. - progression of, 401-403. - stationary, 403. - - - Daedalus, 3, 4, 5, 6. - - _Daily Mail_, London, 314. - - Daimler engine, 99, 150. - - Dante, J. B., 13, 14. - - Dauberck, Dr. W., 403. - - Da Vinci, 8, 9. - - De Bacqueville, 13, 14. - - Delagrange, Leon, 261-263. - - Delcourt, Dupuis, 100. - - De Laland, 16, 18. - - De Lesseps, Count, 327, 328. - - De Lome, Dupuis, 91, 92, 93. - - _Demoiselle_ monoplanes, 324. - - Déperdussin, 339. - - Deutsche de la Meurthe, 120 259. - - Dew point, 358. - - Dientsbach, Carl, vii, 164. - - Distance records, 311-314. - - Doldrums, 381. - - Doubleday, Page & Co., 478. - - Drift, defined, 186. - - Dubonnet, 312. - - Du Cros, Arthur, 131. - - Dutrieu, Helene, 321. - - Dynamic flyers, 174. - - - Endurance records, 311-314. - - Engine, Daimler, 99, 150, 163. - Gnome, 312. - Körting, 139. - Mercedes, 140. - Panhard-Levassor, 136. - Rénault, 311. - Vivinus, 129. - - _Engineering News_, 435. - - English Channel flights, 50-53, 56, 137, 289-292. - - English military dirigibles, 130-137. - - _Eole_, 223. - - Equator of balloon, 76. - - Equilibrium, of angels, 7, 8. - - Esnault-Pélterie, Robert, 304, 314, 337, 340. - - _España_, the, 124, 126, 127. - - Espy, 419, 420. - - Etrich, Igo, 335, 336. - - - Fabre, 332-335. - - Farman, Henri, 259-264, 298, 303, 305, 321. - Maurice, 305, 311. - - Federation Aëronautique International, 322, 323. - - Fequant, Lieutenant, 312. - - Ferber, Captain, 256. - - Ferrel, W., 356, 376-379, 397, 413, 436. - - Fin, 229. - - _Flesselle_, the, 48, 49, 50. - - Flexible balloons, 122, 123. - - Fluctuating winds, 427-439. - cause of, 436-438. - impact of, 435, 436. - - Flying machine, impossibility of, 12, 17. - - Flying machine models, 173 _et seq._ - Abbe’s proposed, 200. - Cayley’s aërial glider, 181, 182. - Da Vinci’s helicopter, 175. - Da Vinci’s parachute, 177, 178. - Forlanini’s helicopter, 200. - Garnerin’s parachute, 179. - Hargrave’s, 190, 191. - Helicopter, 198-201. - Henson’s aëroplane, 182-184. - Henson and Stringfellow’s, 184, 185, 187. - Langley’s, 192-197. - Launoy and Bienvenu’s, 198, 199. - Lenormand’s parachute, 177, 178. - Paper traveling parachutes, 180, 181. - Penaud’s toy, 188. - Phillips’ aëroplane, 191, 192. - Phillips’ helicopter, 199. - Tatin’s aëroplane, 189. - Veranzio’s parachute, 177, 178. - Wenham’s aëroplane, 185, 186. - Zanonia Macrocarpa, 180. - - Forbes, A. Holland, 6. - - Forlanini, Professor, 200. - - Fort Myer flights, 138, 272, 275-281. - - Foulois, Lieutenant Benjamin, 278. - - _France_, the, 93-97. - - Franklin, Benjamin, 48, 446. - - Free air, composition of, 349. - conditions of precipitation in, 351, 352. - critical points of constituents of, 351. - dynamical properties of dry, 353, 356. - friction of, 239. - humidity and density of, 358-361. - kinds of expansion of, 361, 362. - properties of moist, 357, 361. - - French Academy, 17, 35. - - French dirigibles, 88-129. - - - Garnerin, Jacques, 179. - - Garros, 324. - - Gasnier, Réné, 340. - - German Airship Society, 166, 167. - - German dirigibles, 138-169. - - Giffard, Henri, 71, 88, 89, 90, 91. - - Glaisher, James, 68-70. - - Gliding machines, 203-221, 245-248. - - Gnome engine, 312, 331, 340. - - Godard, 62, 74, 129. - - Gold-beater skin balloons, 30, 88. - - Grade, 314. - - Grahame-White, Claude, 315, 316, 319, 325, 327, 328. - - Gravitational stability, 233. - - Green, Charles, 54. - - Gross, Major von, 138. - - Gross dirigibles, 138, 139, 140. - - Guide rope, or drag rope, 56, 76, 111, 114. - - - Hailstorms and hailstones, 415-419. - - Hamilton, C. K., 313. - - Hammer, W. J., vii. - - Hangar, 126. - - Hänlein, 98, 99. - - Hann, 365. - - Hanriot, 339. - - Hargrave, Lawrence, 190, 191, 250, 260, 339. - - Harmon, Clifford B., 321. - - Hawley, A. R., 75. - - Hazen, Prof. H. A., 435. - - Hearne, 131, 228. - - Helicopters, 198-201. - - Helmholtz, Prof. Ludvig von, 436-438. - - Henson, 182-184. - - Herring, A. M., 218-222, 245, 271. - - Holland, Robert, 54. - - Hopkinson, Francis, 84. - - Horner, 414. - - Hoxsey, Arch, 309, 324. - - Huffaker, E. C., 247. - - Hull, best forms of, 88, 97, 98, 113. - stiffening of, by internal pressure, 83, 86. - - Humidity, absolute, 359. - percentage of, 358. - - Humphreys, Dr. W. J., vii, 349, 370. - - Hydro-aëroplanes, 332-334, 481 _et seq._ - - Hydrogen balloon, invention of, 29-31, 35. - first ascent of, 36. - - Hydrogen bubbles, 29. - - - Icarus, 3, 4, 5. - - Ice, launching from, 265. - - Indian seed parachute, 180. - - Inherent stability, 229. - - Insolation, effect on density of air, 364. - quantity of, received, 364-366. - - Isobaric lines and surfaces, 371. - - Isothermal lines, surfaces, 366, 367. - - Isothermal layer, 370. - - Italian Aviation Society, 318. - - Italian military dirigibles, 130. - - - _Jaune_, the, 115, 116. - - Jefferson, Thomas, 84. - - Jeffries, 50. - - Johnstone, Ralph, 309, 324, 329. - - Jullien, 88. - - Julliot, Henri, 115, 134, 136. - - _June Bug_, the, 266, 267. - - - Kai Kaoos, 8, 9, 10. - - Kapferer, H., 120, 294. - - Keel surface, 120. - - Kinet, Daniel, 312. - - Kinetic stability, 233. - - Kite balloon, 77. - - Körting, 139. - - Krebs, Captain, 93-97. - - Kress, Wilhelm, 214. - - - _La Belgique_, 129. - - _La España_, 124, 126, 127. - - _La Flesselle_, 48, 49, 50. - - _La France_, 93-97. - - Lahm, Lieutenant Frank P., 272, 277. - - _La Liberté_, 120. - - Lambert, Count de, 273, 302. - - Lana, 23, 24. - - _La Nature_, 312. - - Land-and-sea breezes, 392. - - Landelle, G. de la, 203. - - Langley, S. P., 187, 192-197, 211, 231, 232, 239-245, 251, 427, - 433, 434, 439. - - _La Patrie_, 115, 118, 119, 459-465. - - _La République_, 115, 118, 119. - - _La Russie_, 120. - - Latent heat of condensation, 364. - - Lateral balance of aëroplane, 229-231. - - Latham, Hubert, 283, 288-290, 291, 319, 320, 324. - - Launching an aëroplane, 202, 230, 256, 258, 259, 265. - - Launching methods, 202, 240, 258, 259, 265. - - Launoy and Bienvenu, 198, 199. - - Laurens, 314. - - _La Ville de Paris_, 120-123. - - _Lebaudy_, the, 116, 117. - - Le Blanc, Alfred, 273, 290, 310, 313, 326, 331. - - _Le Clément-Bayard_, 123, 131-133, 456-459. - - _Le Colonel Renard_, 124, 126. - - Lefebvre, 293. - - Leganeaux, U. G., 311, 319. - - Lenormand, Sebastien, 177, 178. - - Levino, A. S., vii. - - Lift, defined, 186. - - Lilienthal, Otto, 210-216, 250. - - _London Daily Mail_, 289. - - Loomis, 402, 414. - - Lord Rayleigh, 6, 427. - - - McCurdy, J. A. D., 264. - - MacMechen, 164. - - Madison, James, 84. - - Malecot, 123. - - Maloney, D., 251-255. - - Manley, Charles M., 242, 245, 251, 285. - - Marconnet, Captain, 312. - - Marey, Professor, 427. - - Marvin, Prof. C. F., 435. - - Mason, Monck, 55. - - Mattullath, Hugo, 231, 235-239. - - Maxim, Sir Hiram S., 226-228, 245. - - Mendoza, 19. - - Mercedes, 140. - - _Meteorological Journal_, 435. - - Meusnier, General, 85, 86. - - Michelin prize, 273, 303, 311, 314, 321. - - Milton, 7. - - Moisant, John, 31, 328. - - Monaco, Prince of, 111. - - Monge, Marey, 100. - - Monoplane, 174. - - Monsoons, 385-391. - - Montgolfier, 29, 37, 50. - - _Montgolfière_, 42. - - Montgomery, Prof. J. J., 251-255, 282, 339. - - Moore, Willis L., 349, 405, 422. - - Morane, 310. - - _Morning Post_, 131, 134-137. - - Motors, 340. - Antoinette, 254, 258. - Clément-Bayard, 458. - Daimler, 99, 150, 163. - Electrical, 92, 95. - Gnome, 312. - Körting, 139. - Mercedes, 140. - Panhard-Levassor, 136. - Rénault, 311. - steam, 228, 234. - Vivinus, 129. - - Mouillard, L. P., 206-209. - - Mountain-and-valley winds, 293. - - Munn & Co., 481. - - Muscular flight, 3-7. - - - Nadar’s balloon, the _Geant_, 60. - - _Nassau, Great Balloon of_, 55. - - _Nature_, 217, 427. - - Nieuport, 339. - - Northcliffe, Lord, 305. - - - Olieslaegers, Jan, 311. - - Orthopters, 174. - - Ovid, 3. - - - Panhard-Levassor, 136. - - Parachutes, 176-81. - - Parseval dirigibles, 138, 140-143. - - Parseval, Major von, 77, 138. - - Passive fliers, 174. - - _Patrie_, the, 115, 118, 119, 459-465. - - Paulhan, Louis, 284, 293-296, 305, 311, 315, 316, 317, 324, 325. - - Peltier, H., 456. - - Pénaud, A., 188. - - Pendular stability, 233. - - _Philadelphia Ledger_, the, 313. - - Phillips, Horatio, 191, 192, 199. - - Picardie military maneuvers, 131. - - Pilcher, 216-218, 246. - - Polignac, Marquis de, 301. - - Porter, Rufus, 86, 87. - - Post, Augustus, 6, 75. - - Power expended in flight, 6, 7. - - Power flyers, 174. - - Pressure, critical, 351. - atmospheric, 370-374. - - _Preussen_, the, 70. - - Projectile stability, 232. - - Propeller, Chauvière, 125, 136. - - Puy de Dome, 314. - - Pylons, 292. - - - Rayleigh, Lord, 6, 427. - - Records, aëroplane, - altitude, 307-309. - cross-country, 311-314. - distance, 311. - duration, 311-314. - load, 311-314. - speed, 310-311. - - _Red Wing_, 265, 266. - - Relative humidity, 358. - - Renard, Captain, 93-97, 210. - - _République_, the, 115, 118, 119. - - Reye, Dr., 414. - - Rheims aviation contests, 292-301. - - Riedinger, August, 140. - - Rigid balloons, 122. - - Robert, 42, 45, 81, 82, 83. - - Roc, 11. - - Rolls, Hon. C. S., 321. - - Romain, 52. - - Rotch, A. Lawrence, 380-382. - - Rougier, 302. - - Rozier, Pilâtre de, 38, 52. - - Rudders, aëroplane, 245, 246. - three-torque, 229-231, 247, 248. - - Ruskin, John, 7. - - _Russie_, the, 120. - - Ryan, Allan A., 327. - Thomas F., 327. - - - Sabathier, 131, 132. - - Saddle bird, 8. - - Saint-Marcq, Com. Le Clément, 438. - - Sandt, Emile, 153. - - Santos-Dumont, Alberto, 102-114, 303, 324, 356-359. - - Saturation, 358. - - Scaliger, 10. - - Schottus, 19. - - Schwartz, 99, 100. - - _Scientific American_, 86, 153, 443, 481. - - Screw, da Vinci’s, 176. - metal, 340. - radial-arm, 129, 242, 340. - wooden, 339. - - Selfridge, Lieutenant T., 264, 265. - - _Signal Corps Dirigible No. 1_, 138, 476, 477. - - Signal Corps, U. S., vi, 271, 272, 276-281. - - Signal Service, U. S., 417-419. - - Sigsfeld, Captain von, 77. - - _Silver Dart_, 305. - - Skin-friction, 238, 239. - - Soaring, early attempts at, 13. - winds helpful to, 303, 393, 403, 431, 425-459. - - Society for the Study of Motor Air Ships, 138. - - Sommer, Roger, 284, 293. - - Sopwith, Thomas, 314. - - Speed records, 310, 311. - - Spratt, G. A., 247. - - Squier, Major George Owen, 279, 459. - - St. Louis tornado, 412, 413. - - Stabilizing planes, 86. - - Stability and steadiness, artificial, 229-231. - automatic, 218, 220, 229. - three-axial, 229, 234. - - Statoscope, 76. - - Statue of Liberty Prize, 325. - - Stringfellow, 184, 185, 187. - - Surcouf, 115. - - Süring, Dr., 70. - - - Tabuteau, Maurice, 311. - - Tasso, 3. - - Tatin, Victor, 189. - - Tellier monoplane, 312. - - Temperature, critical, 351. - distribution of, 366-370. - gradient, 367. - vertical gradient, 367-369. - - Temperature of the air, 363 _et seq._ - - Teisserenc de Bort, 380-382. - - _The New York Times_, 313. - - Three-rudder principle, 229-232. - - Thunderstorms, genesis and propagation of, 423, 424. - nature of, 422 _et seq._ - - Tidswell, Ella, 216. - - Tissandier, Gaston, 273, 283, 293. - - Tornadoes, bursting of, 419-420 _et seq._ - destructive power of, 409, 410. - dry, 420, 421. - dynamics of, 406-409. - genesis of, 405-406. - hail and snow, 415-419. - misty, 411 _et seq._ - nature of, 404. - sections of, 409-417. - - Tractional balance, 254. - - Trade-winds and antitrade, 380-383. - - Transatlantic voyages, 74, 75, 381, 383. - - Triplanes, 175. - - Types of flyers, 174. - balloons, 122. - - - United States Signal Corps, vi, 271, 272, 276-281. - - United States War Department, 138, 196, 271, 272, 275-281. - - United States Weather Bureau, iv. - - - Vacuum balloon, 18, 24, 25, 443-445. - - Van der Born, 312. - - Varnish bubbles, 30. - - Vaulx, Count de la, 74, 127, 129. - - Veranzio, Fauste, 177. - - _Ville de Nancy_, the, 124, 125. - - _Ville de Paris_, the, 120-123. - - Vivinus, 129. - - Voisin, 259, 267, 313. - - Von Bezold, 424. - - - Waterspouts, analysis of St. Louis, 412, 413. - nature of, 411 _et seq._ - - Weiller prize, 314. - - Wellman, Walter, 25, 75, 383. - - Wenham, 185, 186, 245. - - Weyman, 314, 331. - - _White Wing_, the, 266. - - Wilkins, 10. - - Winans, Ross, 320. - - Wind gusts, distribution of, 425, 426. - energy of, 435, 436. - instrumental study of, 427-459. - nature of, 425 _et seq._ - soaring value of, 426, 427, 439. - sustaining force of, 426. - - Winds, ascending trend of, 211. - cause of periodic, 383. - cyclonic, 394 _et seq._ - diurnal, 392-393. - dry whirl, 420, 421. - fluctuations of, 427-439. - general cause of, 363, 364. - kinds of permanent, 380. - kinds of periodic, 383. - monsoon, 385, 391. - nonperiodic, 394 _et seq._ - nonvortical, 422 _et seq._ - permanent and periodic, 376 _et seq._ - prevailing westerlies, 380, 382, 383. - trade-winds and antitrade, 380, 381. - useful for voyages, 381, 383. - in soaring, 303, 393, 403, 421, 425-439. - - Wise, John, 73, 74, 383, 415, 416. - - Wölfert, 99. - - _World_, the New York, 313, 316. - - Wright brothers, 245-251, 270-282, 309, 324, 326, 329, 338, 478. - - Wynmalen, Henri, 321. - - - Zahm, 30, 97, 113, 221, 229-231, 239, 245, 334, 427-432, 443. - - Zanonia Macrocarpa, 180. - - Zeppelin, Count Ferdinand von, 102. - - Zeppelin Airship Construction Co., 158, 161. - - Zeppelin dirigibles, 145, 169. - - Zodiac balloons, 127, 128, 129. - - - - -+----------------------------------------------------------------------+ -| | -| FOOTNOTES: | -| | -| [1] With apologies to the California professor who will ride on | -| wings worked by muscular force alone. | -| | -| [2] Mr. A. Holland Forbes and Mr. Augustus Post, in the | -| international balloon race of 1908, used a balloon having too | -| long a neck, thus causing such pressure at its top as to burst | -| the bag. A dreadful plunge ensued, landing them on a house, but | -| without injury, as the netting and collapsed bag dampened their | -| speed of fall. It is reported that they crashed through the | -| skylight, and that the lady of the house regretted not being | -| there to receive them. | -| | -| [3] _Mechanical Principles of Flight._ | -| | -| [4] The reader may like to know that the basis of so much confidence | -| was that ancient Euclidean theorem connecting the surfaces and | -| volumes of similar figures with certain powers of their | -| homologous linear dimensions. | -| | -| [5] The writer has made hydrogen-inflated varnish bubbles a foot | -| in diameter which ascended swiftly to the ceiling; also, | -| air-inflated varnish bubbles a foot and a half in diameter | -| which lasted an hour. These, if suitably heated, may be made | -| to ascend; but this experiment is more difficult. | -| | -| [6] Both had studied science in college. Stephen was an | -| accomplished architect; Joseph, the author of many important | -| inventions, among others the common lamp chimney, the | -| hydraulic press, etc. | -| | -| [7] A long patch on the balloon that can be ripped open for the | -| sudden release of gas. | -| | -| [8] The equator of such a balloon is its horizontal great circle. | -| | -| [9] A similar suggestion was made by Thomas Jefferson in a letter | -| to Prof. James Madison, and dated from Paris in 1785: “I went | -| some time ago to see a machine which offers something new. A | -| man had applied to a light boat a very large screw, the thread | -| of which was a thin plate, two feet broad, applied by its edge | -| spirally around a small axis. It somewhat resembled a bottle | -| brush, if you will suppose the hairs of the bottle brush | -| joining together, and forming a spiral plane. This, turned on | -| its axis in the air, carried the vessel across the Seine. It | -| is, in fact a screw which takes hold of the air and draws | -| itself along by it; losing, indeed, much of its effort by the | -| yielding nature of the body it lays hold of to pull itself on | -| by. I think it may be applied in the water with much greater | -| effect and to very useful purposes. Perhaps it may be used | -| also for the balloon.” | -| | -| [10] _La Navigation Aerienne_, Gaston Tissandier. | -| | -| [11] The motive power equals the product of the speed and | -| resistance. But in the assumed case, the speed is doubled and | -| the resistance quadrupled; hence, the power required is | -| eightfold. | -| | -| [12] Santos-Dumont, _My Airships_. | -| | -| [13] m^3 signifies cubic meters. One cubic meter equals 35.3166 | -| cubic feet. | -| | -| [14] Hangar, an airship harbor, or garage. | -| | -| [15] Aëronat, an airship of the lighter-than-air kind. | -| | -| [16] Hearne, _Airships in Peace and War_. | -| | -| [17] _Over Sea by Air-Ship_, MacMechen and Dienstbach, _The | -| Century_, May, 1910. | -| | -| [18] A mathematical argument against this device is presented in | -| Appendix I. | -| | -| [19] It is commonly reported by navigators that the albatross | -| “sports in the tempest” on unbeating pinions; but it may be | -| questioned whether any bird can make headway against the | -| swiftest winds. | -| | -| [20] The “drift” and “lift” are the components of surface | -| wind-pressure respectively in the direction of flight and at | -| right angles to it. | -| | -| [21] The tandem monoplane, or two lifting planes arranged in | -| tandem, was invented by D. S. Brown and exhibited to the | -| Aëronautical Society of Great Britain in 1873. | -| | -| [22] This gasoline aëroplane model was previously tested in | -| private many times, both with single surface wings, and with | -| superposed surfaces. | -| | -| [23] Abbe, _Helicopters for Aërial Research_, _Aëronautics_, Feb. | -| 1909. | -| | -| [24] _L’Empire de l’Air._ | -| | -| [25] _Progress in Flying Machines_, Chanute. | -| | -| [26] The air rises with increased temperature, hence with | -| increased volume displacement, thus causing the wind in | -| general to have a slightly ascending trend. | -| | -| [27] _Aëronautical Annual, 1897._ | -| | -| [28] Ella Tidswell, _The Aëronautical Journal_, July, 1909. | -| | -| [29] W. J. S. Lockyer, _Nature_, August 12, 1897. | -| | -| [30] Wenham used superposed planes, Stringfellow superposed | -| planes trussed by vertical rods and diagonal wires, Phillips, | -| Lilienthal and Hargrave superposed arched surfaces. | -| | -| [31] See _Aëronautic Annual_, 1896. | -| | -| [32] _Aërial Warfare_, Hearne, p. 77. | -| | -| [33] Published by the _American Engineer and Railway Journal._ | -| | -| [34] This kind of automatic stability may be called inherent | -| stability. | -| | -| [35] Models embodying the above devices had been made and flown | -| by the writer some years previously; but aside from these it | -| is obvious that a Phillips’s aëroplane and other kinds can | -| be effectively controlled in flight by the above-proposed | -| three-torque system. | -| | -| [36] This idea was later materialized in Langley’s gasoline | -| biplane. | -| | -| [37] The means for balancing here suggested in italics was | -| claimed some years later in Mr. Hugo Mattullath’s patent | -| application in which the inventor had the assistance of the | -| present writer. | -| | -| [38] A nearly equivalent vertical surface was used in Dr. | -| Langley’s large “aërodrome.” It was a wind-vane rudder placed | -| well below and to the rear of the centroid, to be used in | -| turning corners. The pressure on this rudder would tilt the | -| aëroplane toward the center of curvature of the path, and turn | -| it about the vertical axis, but would conspire with the | -| centrifugal force. If placed above and forward, it would give | -| the desired moments, but oppose the centrifugal force. | -| | -| [39] He died of apoplexy, January 31, 1902. | -| | -| [40] The first flights were to be made from the water. | -| | -| [41] It can be shown that the angle of flight requiring the least | -| motive power is that which makes the wing resistance, or | -| drift, three fourths of the entire resistance to progression. | -| | -| [42] _Atmospheric Resistance on Even Surfaces_, by A. F. Zahm, | -| _Phil. Soc. Washington_. | -| | -| [43] The term “aërodrome” is now commonly applied to an aviation | -| field. | -| | -| [44] On August 25, 1909, Louis Paulhan, in the aviation contest | -| at Rheims, flew 82 miles in 2 hours, 43 minutes and 24 | -| seconds, preserving his lateral balance without the aid of | -| torsion-wing mechanism and in a turbulent atmosphere. | -| | -| [45] _Aërial Locomotion_, A. G. Bell, Washington Academy of | -| Science, March 4, 1907. | -| | -| [46] The Wrights in 1910 adopted the rear horizontal and vertical | -| rudder, thus returning to the design of their predecessors. | -| | -| [47] On July 18, 1905. | -| | -| [48] These glides were abandoned as too dangerous and roundabout, | -| in favor of direct tentative flights with a motor. | -| | -| [49] Falling weights pulling a cord that accelerates the | -| aëroplane at starting. | -| | -| [50] _Present Status of Military Aëronautics_, _Journal of the | -| American Society of American Engineers_, December, 1908. | -| | -| [51] On September 18, 1906, Montgomery received a U. S. patent on | -| an aëroplane having curved wings and three-rudder control, the | -| Wright brothers having on May 22, 1906, received a patent on | -| an aëroplane having normally flat wings and three-rudder | -| control. | -| | -| [52] The daring aviator escaped without a scratch, but his | -| propeller and running gear were damaged slightly. | -| | -| [53] This was an official record, but Brookins had flown 4939 | -| feet high, at Indianapolis, on June 17th. | -| | -| [54] This record was made with an uncalibrated barograph, and | -| hence was unofficial and unaccepted as a world’s record. | -| | -| [55] The present writer, in his paper quoted on page 229, pointed | -| out the equilibrative and steadying quality of torsionally | -| elastic wings, and some years previously had proved this by | -| gliding models having sustainers with flexible rear margins. | -| | -| [56] The whole water vapor in the atmosphere of our latitude in | -| summer is equivalent to about one inch of rainfall. | -| | -| [57] Computed by W. J. Humphreys for Moore’s _Descriptive | -| Meteorology_. | -| | -| [58] Ferrel, _Popular Treatise on Winds_. | -| | -| [59] Solar radiation received by the earth. | -| | -| [60] W. J. Humphreys, _Astro. Phys. Journ._, January, 1909. | -| | -| [61] An isobar is a line of intersection of an isobaric surface | -| with a water level surface at any altitude. | -| | -| [62] _A Popular Treatise on the Winds._ | -| | -| [63] _The Conquest of the Air._ | -| | -| [64] By this current John Wise, in 1870, and Walter Wellman, in | -| 1910, proposed to voyage across the Atlantic; Wise in a free | -| balloon, Wellman in a motor balloon with drag rope. See pp. | -| 74, 75. | -| | -| [65] It is reported that once during the month of August the | -| rainfall totaled thirty-two feet; and it is believed that the | -| annual fall exceeds fifty feet. | -| | -| [66] The “eye” is most noticeable at sea, where the cyclones are | -| more symmetrical, and particularly in lower latitudes, where | -| they are more concentrated. | -| | -| [67] The destructive one that visited Galveston in 1900 is a | -| well-known example. | -| | -| [68] _Contributions to Meteorology._ | -| | -| [69] Dr. W. Dauberck, _Met. Zeitschrift_, April, 1866. | -| | -| [70] Moore’s _Meteorology_, p. 164. | -| | -| [71] Von Bezold, on the _Thermodynamics of the Atmosphere_. | -| | -| [72] Chanute, _Aeronautical Annual_, 1897, p. 101. | -| | -| [73] _Nature_, April 5, 1883. | -| | -| [74] _Vol des Oiseaux._ | -| | -| [75] _Internal Work of the Wind._ | -| | -| [76] _Engineering News_, December 13, 1890. | -| | -| [77] _Meteorological Journal_, November, 1891. | -| | -| [78] On _Atmospheric Movements_ (Abbe’s translation). | -| | -| [79] From _Scientific American_, March 13, 1909, by permission of | -| Munn & Co. | -| | -| [80] For a fuller account of this fine airship see H. Peltier’s | -| article in _L’Aérophile_, December 1, 1910. | -| | -| [81] This description and the following are from _Present Status | -| of Military Aëronautics_, by Major G. O. Squier. | -| | -| [82] From _Navigating the Air_, by permission of Doubleday, Page | -| & Co. | -| | -| [83] From _Scientific American_ of March 4, 1911, by permission | -| of Munn & Co. | -| | -+----------------------------------------------------------------------+ - - - Transcriber’s Notes: - - Text enclosed by underscores is in italics (_italics_). - - Redundant title page has been removed. - - Blank pages have been removed. - - Silently corrected typographical errors. - - - - - -End of Project Gutenberg's Aërial Navigation, by Albert Francis Zahm - -*** END OF THIS PROJECT GUTENBERG EBOOK AËRIAL NAVIGATION *** - -***** This file should be named 60277-0.txt or 60277-0.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/6/0/2/7/60277/ - -Produced by ellinora, Robert Tonsing, and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive/American Libraries.) - -Updated editions will replace the previous one--the old editions will -be renamed. - -Creating the works from print editions not protected by U.S. copyright -law means that no one owns a United States copyright in these works, -so the Foundation (and you!) can copy and distribute it in the United -States without permission and without paying copyright -royalties. 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