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diff --git a/15050.txt b/15050.txt new file mode 100644 index 0000000..b342701 --- /dev/null +++ b/15050.txt @@ -0,0 +1,5190 @@ +The Project Gutenberg EBook of Scientific American Supplement, No. 810, +July 11, 1891, by Various + +This eBook is for the use of anyone anywhere 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 + + +Title: Scientific American Supplement, No. 810, July 11, 1891 + +Author: Various + +Release Date: February 14, 2005 [EBook #15050] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN *** + + + + +Produced by Juliet Sutherland and the PG Online Distributed +Proofreading Team at www.pgdp.net. + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 810 + + + + +NEW YORK, JULY 11, 1891 + +Scientific American Supplement. Vol. XXXII, No. 810. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + * * * * * + + + + +TABLE OF CONTENTS. + + +I. BOTANY.--Cocos Pynaerti.--A new dwarf growing palm.--1 illustration. + +II. CHEMISTRY.--The Application of Electrolysis to Quantitative + Analysis.--By CHARLES A. KOHN, B.Sc., Ph.D.--Applicability of + these methods to poison determinations. + +III. CIVIL ENGINEERING.--The Kioto-Fu Canal in Japan.--A + Japanese canal connecting the interior of the country with the + sea.--3 illustrations. + + The Iron Gates of the Danube.--An important engineering work, + opening a channel in the Danube.--1 illustration. + + The New German Ship Canal.--Connection of the Baltic with + the North Sea.--Completion of this work.--1 illustration. + + Transit in London, Rapid and Otherwise.--By JAMES A. TILDEN. + --A practical review of London underground railroads and their + defects and peculiarities. + +IV. ELECTRICITY.--An Electrostatic Safety Device.--Apparatus + for grounding a circuit of too high potential.--1 illustration. + + Experiments with High Tension Alternating Currents.--Sparking + distance of arc formed by a potential difference of 20,000 volts. + --1 illustration. + + Laying a Military Field Telegraph Line,--Recent field trials in + laying telegraph line in England.--3 illustrations. + + Some Experiments on the Electric Discharge in Vacuum Tubes. + --By Prof. J.J. THOMSON, M.A., F.R.S.--Interesting experiments + described and illustrated.--4 illustrations. + + The Electrical Manufacture of Phosphorus.--Note upon a new + English works for this industry. + +V. GEOGRAPHY.--The Mississippi River.--By JACQUES W. REDWAY. + --An interesting paper on the great river and its work and + history. + +VI. MECHANICAL ENGINEERING.--How to Find the Crack.-- + Note on a point in foundry work. + + Riveted Joints in Boiler Shells.--By WILLIAM BARNET LE + VAN.--Continuation of this practical and important paper. + --10 illustrations. + +VII. MEDICINE AND HYGIENE.--Influence of Repose on the Retina. + --Important researches on the physiology of the eye. + + The Relation of Bacteria to Practical Surgery.--By JOHN B. + ROBERTS, A.M., M.D.--A full review from the surgeon's standpoint + of this subject, with valuable directions for practitioners. + +VIII. MINERALOGY.--Precious and Ornamental Stones and Diamond + Cutting.--By GEORGE FREDERICK KUNZ.--An abstract + from a recent census bulletin, giving interesting data. + +IX. MINING ENGINEERING.--Mine Timbering.--The square system + of mine timbering as used in this country in the Pacific coast + mines and now introduced into Australia.--1 illustration. + +X. MISCELLANEOUS.--Freezing Mixtures.--A list of useful freezing + mixtures. + + Sun Dials.--Two interesting forms of sun dials described. + --3 illustrations. + + The Undying Germ Plasm and the Immortal Soul.--By DR. R. + VON LENDENFELD.--A curious example of modern speculative + thought. + +XI. NAVAL ENGINEERING.-The New British Battle Ship Empress + of India.--A first class battle ship recently launched at + Pembroke dockyard. + +XII. TECHNOLOGY.--Composition of Wheat Grain and its Products + in the Mill.--A scientific examination of the composition of + wheat and its effect on mill products. + + Fast and Fugitive Dyes.--By Prof. J.J. HAMMEL.--Practical + notes from the dyer's standpoint upon coloring agents. + + * * * * * + + + + +MINE TIMBERING. + + +The square system of timbering, in use in most of our large mines on +the Pacific coast, was first introduced in Australia by Mr. W.H. +Patton, who adopted it in the Broken Hill Proprietary mines, although +it does not seem to be so satisfactory to the people there as to our +miners, who are more familiar with it. The accompanying description +and plans were furnished by Mr. Patton to the report of the Secretary +of Mines for Victoria: + + "The idea is supposed to have originated in the German mines, + but in a crude form. It was introduced among the mines of the + Pacific coast of America some 20 years ago, by a gentleman + named Diedesheimer. Its use there is universal, and experience + has evolved it from the embryo state to its present + perfection. The old system and its accompanying disadvantages + are well known. A drive would be put in for a certain + distance, when it had to be abandoned until it could be filled + up with waste material and made secure. This process entailed + much expense. The stuff had first to be broken on the surface, + then sent below, trucked along the drives, and finally + shoveled into place. Ventilation was impaired and the drives + were filled with dust. The men worked in discomfort, and were + not in a condition to perform a full measure of labor. Under + the system as adopted in the Proprietary mine, these + disadvantages disappear. The cost is one-third less, + ventilation is perfect, and every portion of the faces are + accessible at all times. Sawn timber is used throughout; the + upright and cross pieces are 10 inches by 10 inches, and stand + 4 feet 6 inches apart; along the course of the drive, the + cross pieces are five feet in length, and the height of the + main drives and sill floor sets are 7 feet 2 inches in the + clear. In blocking out the stopes, the uprights are 6 feet 2 + inches, just one foot shorter than those in the main drives. + The caps and struts are of the same dimensions and timber as + the sill floor. The planks used as staging are 9 inches by 21/2 + inches; they are moved from place to place as required, and + upon them the men stand when working in the stopes and in the + faces. A stope resembles a huge chamber fitted with + scaffolding from floor to roof. The atmosphere is cool and + pure, and there is no dust. Stage is added to stage, according + as the stoping requires it, and ladders lead from one floor to + the other; the accessibility to all the faces is a great + advantage. + + If, while driving, a patch of low grade ore is met with, it + can be enriched by taking a higher class from another face, + and so on. Any grade can be produced by means of this power of + selection. Opinions have been expressed that this system of + timbering is not secure, and that pressure from above would + bring the whole structure down in ruins. But an opinion such + as this is due to miscomprehension of the facts. If signs of + weakening in the timbers become apparent, the remedy is very + simple. Four or more of the uprights are lined with planks, + and waste material is shot in from above, and a strong support + is at once formed, or if signs of crushing are noticed, it is + possible to go into the stope, break down ore, and at once + relieve the weight." + +[Illustration: THE SQUARE SYSTEM OF TIMBERING IN MINES.] + + * * * * * + + + + +TRANSIT IN LONDON, RAPID AND OTHERWISE.[1] + + [Footnote 1: Abstract from a paper read before the Boston Society + of Engineers, in April, 1890.] + +By JAMES A. TILDEN. + + +The methods of handling the travel and traffic in the city of London +form a very interesting subject for the study of the engineer. The +problem of rapid transit and transportation for a city of five +millions of inhabitants is naturally very complicated, and a very +difficult one to solve satisfactorily. + +The subject may be discussed under two divisions: first, how the +suburban travel is accommodated, that is, the great mass of people who +come into the business section of the city every morning and leave at +night; second, how the strictly local traffic from one point to +another is provided for. Under the first division it will be noted in +advance that London is well provided with suburban railroad +accommodation upon through lines radiating in every direction from the +center of the city, but the terminal stations of these roads, as a +rule, do not penetrate far enough into the heart of the city to +provide for the suburban travel without some additional methods of +conveyance. + +The underground railroad system is intended to relieve the traffic +upon the main thoroughfares, affording a rapid method of +transportation between the residential and business portions, and in +addition to form a communicating link between the terminals of the +roads referred to. These terminal stations are arranged in the form of +an irregular ellipse and are eleven in number. + +One of the most noticeable features of the underground system in +London is that it connects these stations by means of a continuous +circuit, or "circle," as it is there called. The line connecting the +terminal stations is called the "inner circle." There is also an +extension at one end of this elliptical shaped circle which also makes +a complete circuit, and which is called the "middle circle," and a +very much larger circle reaching the northern portions of the city, +which is called the "outer circle." The eastern ends of these three +circles run for a considerable distance on the same track. In addition +to this the road branches off in a number of directions, reaching +those parts of the city which were not before accommodated by the +surface roads, or more properly the elevated or depressed roads, as +there are no grade crossings. + +With regard to the accommodation afforded by this system: it is a +convenience for the residents of the western and southern parts of +London, especially where they arrive in the city at any of the +terminal stations on the line of the "circle," as they can change to +the underground. They can reach the eastern end of the "circle," at +which place is located the bank and the financial section of London, +in a comparatively short time. For example, passengers arriving at +Charing Cross, Victoria or Paddington stations, can change to the +underground, and in ten, fifteen and thirty minutes respectively, +reach the Mansion House or Cannon street stations, which are the +nearest to the Bank of England. In a similar manner those arriving at +Euston, St. Pancras or King's Cross on the northern side of the +"circle," can reach Broad Street station in ten or fifteen minutes, +which station is nearest the bank on that side of the "circle." + +In a number of cases the underground station is in the same building +or directly connected by passages with the terminal stations of the +roads leading into the city. Examples of this kind would be such +stations as Cannon Street, Victoria or Paddington. They are not, +however, sufficiently convenient to allow the transference of baggage +so as to accommodate through passengers desiring to make connection +from one station to another across the city. Hand baggage only is +carried, about the same as it is on the elevated road in New York. The +method of cross town transfer, passengers and baggage, is invariably +done by small omnibuses, which all the railroads maintain on hand for +that special purpose. A very large proportion of the travel, however, +if not the largest, is obtained by direct communication by means of +the "circle" on branch lines with the various residential portions of +north, west and south London. + +Approximately on the underground railroad the fare is one cent per +mile for third class, one cent and a half for second class, and two +cents for first class, but no fare is less than a penny, or two cents. +Omnibus fares in some instances are as low as a penny for two miles. +This is not by any means the rule, and is only to be found on +competing lines. The average fare would be a penny a mile or more. + +The fares on the main lines which accommodate the suburban traffic are +somewhat higher than on the underground, perhaps 50 per cent. more. In +every case, on omnibus, tram cars or railroads, the rates are charged +according to distance. The system such as in use on our electric, +cable and horse cars and on the elevated road in New York, of charging +a fixed fare, is not in use anywhere. + +The ticket offices of the underground roads are generally on a level +with the street. In some instances both the uptown and downtown trains +are approached from one entrance, but generally there is an entrance +at either side of the railroad, similar to the elevated railroad +system. In purchasing a ticket, the destination, number of the class, +and whether it is a single or return ticket have to be given. The +passenger then descends by generally well lighted stairways to the +station below, and his ticket is punched by the man at the gate. He +then has to be careful about two things; first, to place himself on +that part of the platform where the particular class which he wishes +to take stops, and secondly, to get on to the right train. In the +formation of the train the first class coaches are placed in the +center, the second and third class respectively at the front and rear +end. There are signs which indicate where passengers are to wait, +according to the class. There is a sign at the front end of the +engine, which to those initiated sufficiently indicates the +destination of the train. The trains are also called out, and at some +stations there is an obscure indicator which also gives the desired +information. The stations are from imperfectly to well lighted, +generally from daylight which sifts down from the smoky London +atmosphere through the openings above. The length of the train +averages about eight carriages of four compartments, each compartment +holding ten persons, making a carrying capacity of 320 passengers. The +equipment of the cars is very inferior. The first class compartments +are upholstered and cushioned in blue cloth, the second class in a +cheaper quality, while most of the third class compartments have +absolutely nothing in the way of a cushion or covering either on the +seat or back, and are little better than cattle pens. The width of the +compartment is so narrow that the feet can easily be placed on the +opposite seat, that is, a very little greater distance than would be +afforded by turning two of our seats face to face. The length of the +compartment, which is the width of the car, is about a foot and a half +less than the width of our passenger cars, about equal to our freight +cars. Each compartment is so imperfectly lighted by a single lamp put +into position through the top of the car that it is almost impossible +to read. + +The length of time which a train remains at a station is from thirty +to forty seconds, or from three to four times the length of time +employed at the New York elevated railroad stations. The reason for +this is that a large proportion of the doors are opened by passengers +getting in or out, and all these have to be shut by the station porter +or guard of the train before the train can start. If the train is +crowded one has to run up and down to find a compartment with a vacant +seat, and also hunt for his class, and as each class is divided into +smoking and non-smoking compartments, making practically six classes, +it will be observed that all this takes time, especially when you add +the lost time at the ticket office and gate. + +The ventilation of the tunnels and even the stations is oftentimes +simply abominable, and although the roads are heavily patronized there +is a great amount of grumbling and disfavor on this account. The +platforms of the stations are flush with those of the cars, so that +the delay of getting in or out is very small, but the doors are so low +that a person above the average height has to stoop to get in, and +cannot much more than stand upright with a tall hat on when he is once +in the car. The monitor roof is unknown. + +The trains move with fair speed and the stations are plainly and +liberally marked, so that the passenger has little difficulty in +knowing when to get out. There are two signs in general use on English +railroads which are very simple and right to the point, namely, "Way +Out" and "Way In," so that when a passenger arrives at a station he +has no question how to get out of it. The ticket is given up as the +passenger leaves the station. There is nothing to prevent a passenger +with a third class ticket getting into a first class compartment +excepting the ominous warning of 40 shillings fine if he does so, and +the liability of having his sweet dreams interrupted by an occasional +inspector who asks to see the denomination of his ticket. All +compartments intended for the use of smokers are plainly marked and +are to be found in each class. Almost the entire part of the railroads +within the thickly settled portions of the city run in closed tunnels. +Outside of this they frequently run in open cuttings, and still +further out they run on to elevated tracks. + +With regard to the equipment of the suburban or surface lines not +belonging to the underground system the description is about the same. +The cars are generally four compartments long and sometimes not +exceeding three. They are coupled together with a pair of links and +fastened to the draw bar on one car and the other thrown over a hook +opposite and brought into tension by a right and left hand screw +between the links. This is obviously very inconvenient for shunting +purposes, especially as the cars are not provided with hand brakes and +no chance to get at them if there were any. Consequently it appears +that when a train is made up it stays so for an indefinite period. A +load of passengers is brought into the station and the train remains +in position until it is ready to go out. As the trains run very +frequently this appears to be a very economical arrangement, as no +shunting tracks are needed for storage. The engine which brings the +train in of course cannot get out until the train goes out with the +next load. Turn tables for the locomotives are but very little used, +as they run as double enders for suburban purposes. + +In conclusion it will be safe to say that the problem of rapid transit +for a city as large as London is far from solved by the methods +described. Although there are a great many miles of underground lines +and main lines, as they have been called throughout the paper, and +although grade crossings have been entirely abolished, allowing the +trains to run at the greatest speed suitable to their frequency, still +there are a great many sections which have to depend entirely upon the +omnibus or tram car. The enormous expense entailed by the construction +of the elevated structures can hardly be imagined. We have but one +similar structure in this country, which is that running from the +Schuylkill River to Broad Street station, in Philadelphia. The +underground system is even more expensive, especially in view of the +tremendous outlay for damages. This goes to show that money has not +been spared to obtain rapid transit. + +After all, the means to be depended upon when one desires to make a +rapid trip from one part of the city to another is the really +admirable, cheap, always ready, convenient and comfortable London +hansom; while the way to see London is from the top of an omnibus, the +most enjoyable, if not the most expeditious, means of conveyance. + + * * * * * + +[Continued from SUPPLEMENT, NO. 809, page 12930.] + + + + +RIVETED JOINTS IN BOILER SHELLS.[1] + + [Footnote 1: A paper read at a meeting of the Franklin Institute. + From the journal of the Institute.] + +By WILLIAM BARNET LE VAN. + + +[Illustration: FIG. 11.] + +Fig. 11 represents the spacing of rivets composed of steel plates +three-eighths inch thick, averaging 58,000 pounds tensile strength on +boiler fifty-four inches diameter, secured by iron rivets +seven-eighths inch diameter. Joints of these dimensions have been in +constant use for the last fourteen years, carrying 100 pounds per +square inch. + +_Punching Rivet Holes._--Of all tools that take part in the +construction of boilers none are more important, or have more to do, +than the machine for punching rivet holes. + +That punching, or the forcible detrusion of a circular piece of metal +to form a rivet hole, has a more or less injurious effect upon the +metal plates surrounding the hole, is a fact well known and admitted +by every engineer, and it has often been said that the rivet holes +ought all to be drilled. But, unfortunately, at present writing, no +drilling appliances have yet been placed on the market that can at all +compare with punching apparatus in rapidity and cheapness of working. +A first-class punching machine will make from forty to fifty holes per +minute in a thick steel plate. Where is the drilling machine that will +approach that with a single drill? + +The most important matter in punching plates is the diameter of the +opening in the bolster or die relatively to that of the punch. This +difference exercises an important influence in respect not only of +easy punching but also in its effect upon the plate punched. If we +attempt to punch a perfectly cylindrical hole, the opening in the die +block must be of the same diameter as the point of the punch, or, at +least, a very close fit. The point of the punch ought to be slightly +larger in diameter than the neck, or upper part, as shown in Figs. 12 +and 13, so as to clear itself easily. When the hole in the bolster or +die block is of a larger diameter than the punch, the piece of metal +thrust out is of larger diameter on the bottom side, and it comes out +with an ease proportionate to the difference between the lower and +upper diameters; or, in other words, it produces a taper hole in the +plate, but allows the punching to be done with less consumption of +power and, it is said, with less strain on the plate. + +[Illustration: FIG. 12.] + +[Illustration: FIG. 13.] + +As to the difference which should exist between the diameter of the +punch and the die hole, this varies a little with the thickness of the +plate punched, or should do so in all carefully executed work, for it +is easy to understand that the die which might give a suitable taper +in a three-fourths inch plate would give too great a taper in a +three-eighths inch plate. There is no fixed rule; practical experience +determines this in a rough and ready way--often a very rough way, +indeed, for if a machine has to punch different thicknesses of plate +for the same size of rivets, the workman will seldom take the trouble +to change the die with every variation of thickness. The maker of +punches and dies generally allows about three sixty-fourths or 0.0468 +of an inch clearance. + +The following formula is also used by punch and die makers: + + Clearance = D = d + 0.2t + +where + D = diameter of hole in die block; + d = diameter of cutting edge of punch; + t = thickness of plate in fractions of an inch; + +that is to say, the diameter of the die hole equals diameter of punch +plus two-tenths the thickness of the plate to be punched. + +_Example_.--Given a plate 3/8 or 0.375 of an inch thick, the diameter +of the punch being 13/16 or 0.8125 of an inch, then the diameter of +the die hole will be as follows: + + Diameter of die hole = 0.8125 + 0.375 X 0.2 = 0.8875 inch diameter, + or say 7/8 or 0.875 inch diameter. + +Punches are generally made flat on their cutting edge, as shown in +Fig. 12. There are also punches made spiral on their cutting edge, as +shown in Fig. 13. This punch, instead of being flat, as in Fig. 12, is +of a helical form, as shown in Fig. 13, so as to have a gradual +shearing action commencing at the center and traveling round to the +circumference. Its form may be explained by imagining the upper cutter +of a shearing machine being rolled upon itself so as to form a +cylinder of which its long edge is the axis. The die being quite flat, +it follows that the shearing action proceeds from the center to the +circumference, just as in a shearing machine it travels from the +deeper to the shallower end of the upper cutter. The latter is not +recommended for use in metal of a thickness greater than the diameter +of the punch, and is best adapted for thicknesses of metal two-thirds +the diameter of the punch. + +Fig. 14 shows positions of punch and attachments in the machine. + +[Illustration: FIG. 14.] + +It is of the greatest importance that the punch should be kept sharp +and the die in good order. If the punch is allowed to become dull, it +will produce a fin on the edge of the rivet hole, which, if not +removed, will cut into the rivet head and destroy the fillet by +cutting into the head. When the punch is in good condition it will +leave a sharp edge, which, if not removed, will also destroy the +fillet under the head by cutting it away. + +Punching possesses so many advantages over drilling as to render it +extremely important that the operation should be reduced to a system +so as to be as harmless as possible to the plate. In fact, no plate +should be used in the construction of a boiler that does not improve +with punching, and further on I will show by the experiments made by +Hoopes & Townsend, of Philadelphia, that good material is improved by +punching; that is to say, with properly made punches and dies, by the +upsetting around the punched hole, the value of the plate is increased +instead of diminished, the flow of particles from the hole into the +surrounding parts causing stiffening and strengthening. + +_Drilling Rivet Holes._--In the foregoing I have not referred to the +drilling of rivet holes in place of punching. The great objection to +drilling rivet holes is the expense, from the fact that it takes more +time, and when drilled of full rivet size we are met with the +difficulty of getting the rivet holes to correspond, as they are when +punched of full rivet diameter. When two plates are drilled in place +together, the drill will produce a _burr_ between the two plates--on +account of their uneven surfaces--which prevents them being brought +together, so as to be water and steam tight, unless the plates are +afterward separated and the burr removed, which, of course, adds +greatly to the expense. + +The difference in strength between boiler plates punched or drilled of +full rivet size may be either greater or less than the difference in +strength between unperforated plates of equal areas of fracture +section. When the metal plates are very soft and ductile, the +operation of punching does no appreciable injury. Prof. Thurston says +he has sometimes found it actually productive of increased strength; +the flow of particles from the rivet hole into the surrounding parts +causing stiffening and strengthening. With most steel and hard iron +plates the effect of punching is often to produce serious weakening +and a tendency to crack, which in some cases has resulted seriously. +With first class steel or iron plates, punching is perfectly +allowable, and the cost is twenty-five per cent. less than drilling; +in fact, none but first class metal plates should be used in the +construction of steam boilers. + +In the original punching machines the die was made much larger than +the punch, and the result was a conical taper hole to receive the +rivet. With the advanced state of the arts the punch and die are +accurately fitted; that is to say, the ordinary clearance for a rivet +of (say) three-fourths of an inch diameter, the dies have about three +sixty-fourths of an inch, the punch being made of full rivet size, and +the clearance allowed in the diameter of the die. + +Take, for example, cold punched nuts. Those made by Messrs. Hoopes & +Townsend, Philadelphia, when taken as specimens of "commercial," as +distinguished from merely experimental punching, are of considerable +interest in this connection, owing to the entire absence of the +conical holes above mentioned. + +When the holes are punched by machines properly built, with the punch +accurately fitted to the die, the effect is that the metal is made to +flow around the punch, and thus is made more dense and stronger. That +some such action takes place seems probable, from the appearance of +the holes in the Hoopes & Townsend nuts, which are straight and almost +as smooth as though they were drilled. + +Therefore I repeat that iron or steel that is not improved by proper +punching machinery is not of fit quality to enter into the +construction of steam boilers. + + + STRENGTH OF PUNCHED AND DRILLED IRON BARS. + + HOOPES & TOWNSEND. + +----------------+------------------+----------------+----------------+ +Thickness of bar|Thickness outside | Punched bars | Drilled bars | + in inches. |of hole in inches.|broke in pounds.|broke in pounds.| +----------------+------------------+----------------+----------------+ + 3/8 or 0.375 | 3/8 or 0.375 | 31,740 | 28,000 | + 3/8 or 0.375 | 3/8 or 0.375 | 31,380 | 26,950 | + 5/8 or 0.625 | 1/4 or 0.25 | 18,820 | 18,000 | + 5/8 or 0.625 | 1/4 or 0.25 | 18,750 | 17,590 | + 5/8 or 0.625 | 3/16 or 0.1875 | 14,590 | 13,230 | + 5/8 or 0.625 | 3/16 or 0.1875 | 15,420 | 13,750 | + 5/8 or 0.625 | 1/8 or 0.125 | 10,670 | 9,320 | + 5/8 or 0.625 | 1/8 or 0.125 | 11,730 | 9,580 | +---------------------------------------------------------------------+ + + +It will be seen from the above that the punched bars had the greatest +strength, indicating that punching had the effect of strengthening +instead of weakening the metal. These experiments have given results +just the reverse of similar experiments made on boiler plates; but the +material, such as above experimented upon, is what should be placed in +boilers, tough and ductile, and the manner of, and care taken in, +punching contribute to these results. + +It is usual to have the rivet holes one-sixteenth of an inch in +diameter larger than the rivets, in order to allow for their expansion +when hot; it is evident, however, that the difference between the +diameters of the rivet hole and of the rivet should vary with the size +of the rivet. + +The hole in the die is made larger than the punch; for ordinary work +the proportion of their respective diameters varies from 1:1.5 to 1:2. + +As I have before stated, the best plate joint is that in which the +strength of the plate and the resistance of the rivet to shearing are +equal to each other. + +In boilers as commercially made and sold the difference in quality of +the plates and rivets, together with the great uncertainty as to the +exact effect of punching the plates, have, so far, prevented anything +like the determination either by calculation or experiment of what +might be accepted as the best proportions of riveted joints. + +In regard to steel plates for boilers Mr. F.W. Webb, of Crewe, +England, chief engineer of the London and Northwestern Railway, has +made over 10,000 tests of steel plates, but had only two plates fail +in actual work; these failures he thought were attributable solely to +the want of care on the part of the men who worked the plates up. + +All their rivet holes for boilers were punched in a Jacquard machine, +the plates then annealed, and afterward bent in rolls; they only used +the reamer slightly when they had three thicknesses of plate to deal +with, as in butt joints with inside and outside covering strips. These +works turn out two locomotive boilers every three days. + +The Baldwin Locomotive Works, which turn out on an average three +locomotives per day, punch all their rivet holes one sixteenth inch +less in diameter and ream them to driven rivet size when in place. +They also use rivets with a fillet formed under head made in solid +dies. + +_Rivets._--Rivets of steel or iron should be made in solid dies. +Rivets made in open dies are liable to have a fin on the shank, which +prevents a close fit into the holes of the plates. The use of solid +dies in forming the rivet insures a round shank, and an accurate fit +in a round hole. In addition, there is secured by the use of solid +dies, a strong, clean fillet under the head, the point where strength +is most needed. + +Commencing with a countersunk head as the strongest form of head, the +greater the fillet permissible under the head of a rivet, or bolt, the +greater the strength and the decrease in liability to fracture, as a +fillet is the life of the rivet. + +If rivets are made of iron, the material should be strong, tough, and +ductile, of a tensile strength not exceeding 54,000 pounds per square +inch, and giving an elongation in _eight inches_ of not less than +twenty-five per cent. The rivet iron should be as ductile as the best +boiler plate when cold. Iron rivets should be annealed and the iron in +the bar should be sufficiently ductile to be bent cold to a right +angle without fracture. When heated it should be capable of being +flattened out to one-third its diameter without crack or flaw. + +[Illustration: FIG. 15. Solid Die Rivet.] + +[Illustration: FIG. 16. Open Die Rivet.] + +If rivets are made of steel they must be low in carbon, otherwise they +will harden by chilling when the hot rivets are placed in the cold +plates. Therefore, the steel must be particularly a low grade or mild +steel. The material should show a tensile strength not greater than +54,000 pounds per square inch and an elongation in _eight inches_ of +thirty per cent. The United States government requirements are that +steel rivets shall flatten out cold under the hammer to the thickness +of one-half their diameter without showing cracks or flaws; shall +flatten out hot to one-third their diameter, and be capable of being +bent cold in the form of a hook with parallel sides without cracks or +flaws. These requirements were thought at first to be severe, but the +makers of steel now find no practical difficulty in meeting these +specifications. + +The forming of the head of rivets, whether of steel or iron, and +whether the heads are conical or semi-spherical, should not be changed +by the process of riveting. The form of the head is intended to be +permanent, and this permanent form can only be retained by the use of +a "hold fast," which conforms to the shape of the head. In the use of +the flat hold fast (in general use in a majority of boiler shops) the +form of the head is changed, and if the rivet, by inadequate heating, +requires severe hammering, there is danger that the head of the rivet +may be "punched" off. By the use of a hold fast made to the shape of +the rivet head, this danger is avoided and the original form of the +head is retained. This feature of the use of proper rivet tools in +boiler shops has not received the attention it deserves. Practical use +of the above named hold fast would soon convince the consumers of +rivets of its value and efficiency. + +The practice of driving rivets into a punched rivet hole from which +the fin or cold drag, caused by the movement of the punch, has not +been removed by reaming with a countersunk reamer, or better still a +countersunk set, should be condemned, as by driving the hot rivet head +down against the fin around the hole in the cold plate caused by the +action of punching the countersunk fillet is not only destroyed, but +it is liable to be driven into the head of the rivet, partially +cutting the head from the shank. If the rivet is driven into a hole +that has been punched with a sharp punch and sharp die, the result is +that the fillet is cut off under the head, and the riveted end is also +cut, and does not give the clinch or hold desired. That is to say, +rivet holes in plates to be riveted should have the burr or sharp edge +taken off, either by countersinking, by reamer, or set. + +_Heating of Rivets._--Iron rivets are generally heated in an ordinary +blacksmith's or rivet fire having a forced blast; they are inserted +with the points down into the fire, so that the heads are kept +practically cool. + +Steel rivets should be heated in the hearth of a reverberatory furnace +so arranged that the flame shall play over the top of the rivets, and +should be heated uniformly throughout the entire length of the rivet +to a cherry red. Particular attention must be given to the thickness +of the fire in which they are heated. + +Steel, of whatever kind, should never be heated in a thin fire, +especially in one having a forced blast, such as an ordinary +blacksmith's or iron rivet furnace fire. The reason for this is that +more air passes through the fire than is needed for combustion, and in +consequence there is a considerable quantity of free oxygen in the +fire which will oxidize the steel, or in other words, burn it. If free +oxygen is excluded steel cannot burn; if the temperature is high +enough it can be melted and will run down through the fire, but +burning is impossible in a thick fire with a moderate draught. + +This is an important matter in using steel rivets and should not be +overlooked; the same principle applies to the heating of steel plates +for flanging. + +_Riveting._--There are four descriptions of riveting, namely: + + (1) Hammered or hand riveting. + + (2) Snapped or set. + + (3) Countersunk. + + (4) Machine. + +For good, sound work, machine riveting is the best. + +Snapped riveting is next in quality to machine riveting. + +Countersunk riveting is generally tighter than snapped, because +countersinking the hole is really facing it; and the countersunk rivet +is, in point of fact, made on a face joint. But countersinking the +hole also weakens the plate, inasmuch as it takes away a portion of +the metal, and should only be resorted to where necessary, such as +around the front of furnaces, steam chests or an odd hole here and +there to clear a flange, or something of that sort. + +Hammered riveting is much more expensive than machine or snapped +riveting, and has a tendency to crystallize the iron in the rivets, +causing brittleness. + +In the present state of the arts all the best machine riveters do +their work by pressure, and not by impact or blow. + +The best machines are those of the hydraulic riveting system, which +combines all of the advantages and avoids all the difficulties which +have characterized previous machine systems; that is to say, the +machine compresses without a blow, and with a uniform pressure at +will; each rivet is driven with a single progressive movement, +controlled at will. The pressure upon the rivet after it is driven is +maintained, or the die is retracted at will. + +[Illustration: FIG. 17.] + +Hydraulic riveting has demonstrated not only that the work could be as +well done without a blow, but that it could be _better done without a +blow_, and that the riveted material was stronger when so secured than +when subjected to the more severe treatment under impact. + +What is manifestly required in perfect riveting is that the metal of +the rivet while hot and plastic shall be made to flow into all the +irregularities of the rivet holes in the boiler sheets; that the +surplus metal be formed into heads as large as need be, and that the +pressure used to produce these results should not be in excess of what +the metal forming the boiler shall be capable of resisting. + +It is well known that metals, when subjected, either cold or hot, to +sufficient pressure, will obey almost exactly the same laws as fluids +under similar conditions, and will flow into and fill all the crevices +of the chamber or cavity in which they are contained. If, therefore, a +hot rivet is inserted into the holes made in a boiler to receive it, +and is then subjected to a sufficient pressure, it will fill every +irregularity of the holes, and thus fulfill one of the conditions of +perfect riveting. This result it is impossible to accomplish with +perfection or certainty by ordinary hand riveting, in doing which the +intermittent blows of an ordinary hammer are used to force the metal +into the holes. With a hydraulic riveting machine, however, an +absolutely uniform and continuous pressure can be imparted to each +rivet, so as to force the hot metal of the rivet into all the +irregularities of the holes in the same way as a hydraulic ram will +cause water to fill any cavity, however irregular. + +[Illustration: FIG. 18.] + +In order to illustrate the relative advantages of machine over hand +riveting, two plates were riveted together, the holes of which were +purposely made so as not to match perfectly. These plates were then +planed through the center of the rivets, so as to expose a section of +both the plates and rivets. From this an impression was taken with +printer's ink on paper and then transferred to a wooden block, from +which Figs. 17 and 18 were made. + +The machine-driven rivet is marked _a_, and _b_ represents the +hammered rivet. + +It will be observed that the machine rivet fills the hole completely, +while the hand rivet is very imperfect. This experiment was tried +several times, with similar results each time. + +The hand rivet, it will be observed, filled up the hole very well +immediately under the head formed by the hammer; but sufficient +pressure could not be given to the metal--or at least it could not be +transferred far enough--to affect the metal at some distance from the +driven head. So great is this difficulty that in hand riveting much +shorter rivets must be used, because it is impossible to work +effectively so large a mass of metal with hammers as with a machine. +The heads of the machine rivets are, therefore, larger and stronger, +and will hold the plates together more firmly than the smaller +hammered heads. + +To drive rivets by hand, two strikers and one helper are needed in the +gang, besides the boy who heats and passes the rivets; to drive each +five-eighths inch rivet, an average of 250 blows of the hammer is +needed, and the work is but imperfectly done. With a machine, two men +handle the boiler, and one man works the machine; thus, with the same +number of men as is required in riveting by hand, five rivets are +driven each minute. + +The superior quality of the work done by the machine would alone make +its use advantageous; but to this is added greatly increased amount of +work done. + +The difference in favor of the riveting machine over hand riveting is +at least _ten_ to _one_. + +In a large establishment a record of the number of rivets driven by +the hand-driving gang, also by the gang at the steam-riveting machine +for a long period of time, in both cases making no allowances of any +kind of delays, the rivets driven per month by each was--for the hand +driven rivets at the rate of twelve rivets per hour, and for the +machine driven rivets, 120 per hour. In the case of the hand driven +rivets the boiler remains stationary and the men move about it, while +the machine driven rivets require the whole boiler to be hoisted and +moved about at the riveting machine to bring each hole to the position +required for the dies. Notwithstanding the trouble involved in +handling and moving the boiler, it shows that it is possible to do ten +times as much work, and with less skilled labor, by the employment of +the riveting machine. + +_Calking._--One great source of danger in boiler making is excessive +joint calking--both inside and out--where a sharp nosed tool is +employed, and for the reason that it must be used so close to the +inner edge of plate as to indent, and in many cases actually cut +through the skin of the lower plate. This style of calking puts a +positive strain upon the rivets, commencing distortion and putting +excessive stress upon rivets--already in high tension before the +boiler is put in actual use. It is, I hope, rapidly becoming a thing +of the past. + +With a proper proportion of diameter and pitch of rivet, all that is +required is the use of a light "fuller tool" or the round-nosed tool +used in what is known to the trade as the "Connery system." + +There is but little need of calking if means are taken to secure a +clean metal-to-metal face at the joint surfaces. When the plates are +put together in ordinary course of manufacture, a portion of the mill +scale is left on, and this is reduced to powder or shaken loose in the +course of riveting and left between the plates, thus offering a +tempting opening for the steam to work through, and is really cause of +the heavy calking that puts so unnecessary a pressure on both plate +and rivet. A clean metallic joint can be secured by passing over the +two surfaces a sponge wet with a weak solution of sal-ammoniac and hot +water, an operation certainly cheap enough both as to materials and +labor required. + +[Illustration: FIG. 19] + +The above cut, Fig. 19, gives an illustration of calking done by +sharp-nosed and round nosed tools, respectively. It will be seen by +Fig. 20 that the effect of a round-nosed tool is to divide the plate +calked, and as the part divided is well driven toward the rivets, a +bearing is formed at _a_, from one-half to three-fourths of an inch, +which increases the strength of joint, and will in no way cut or +injure the surface of the under plate. A perfect joint is thus +secured. + +[Illustration: Fig. 20.] + + * * * * * + + + + +THE NEW BRITISH BATTLE SHIP EMPRESS OF INDIA. + + +The launching of this first-class battle ship was successfully carried +out at Pembroke Dockyard on May 7. She is the second of a class of +eight battle ships built and building under the Naval Defense Act of +1889, which were specially designed to take part in general fleet +actions in European waters. The leading dimensions are: Length, +between perpendiculars, 380 ft.; breadth, extreme, 75 ft.; mean +draught of water, 27 ft. 6 in.; and displacement at this draught, +14,150 tons, which surpasses that of any other ship in the navies of +the world. Previous to the launching of the Royal Sovereign--a sister +vessel--which took place at Portsmouth in February last, the largest +war ships in the British navy were the Nile and Trafalgar, each of +12,500 tons, and these were largely exceeded in displacement by the +Italia, of 13,900 tons, and the Lepanto, of 13,550 tons, belonging to +the Italian navy. + +The Empress of India is built throughout of mild steel, the stem and +stern post, together with the shaft brackets, being of cast steel. +Steel faced armor, having a maximum thickness of 18 in., extends along +the sides for 250 ft. amidships, the lower edge of the belt being 5 +ft. 6 in. below the normal water line. The belt is terminated at the +fore and after ends by transverse armored bulkheads, over which is +built a 3 in. protective steel deck extending to the ends of the +vessel and terminating forward at the point of the ram. Above the belt +the broadside is protected by 5 in. armor, the central battery being +inclosed by screen bulkheads of the same thickness. The barbettes, +which are formed of armor 17 in. thick, rise from the protective deck +at the fore and after ends of the main belt. The principal armor +throughout is backed by teak, varying in thickness from 18 in. to 20 +in., behind which is an inner skin of steel 2 in. thick. The engines +are being constructed by Messrs. Humphreys, Tennant & Co, London, and +are of the vertical triple expansion type, capable of developing a +maximum horse power of 13,000 with forced draught and 9,000 horse +power under natural draught, the estimated speeds being 16 and 171/2 +knots respectively at the normal displacement. The regular coal supply +is 900 tons, which will enable the ship to cover a distance of 5,000 +knots at a reduced speed of ten knots and about 1,600 knots at her +maximum speed. The main armament of the Empress will consist of four +67 ton breechloading guns mounted in pairs _en barbette_. The +secondary armament includes ten 6 in. 100 pounder quick firing guns, +four being mounted on the main deck and six in the sponsons on the +upper deck, sixteen 6 pounder and nine 3 pounder quick-firing guns, in +addition to a large number of machine guns. + +The largest guns at present mounted in any British warship are the 110 +ton guns mounted in the Benbow class, and the difference between these +weapons and those to be carried by the Empress of India is very +marked. + +The projectile fired from either of the Benbow's heavy gun weighs +1,800 lb., and is capable of penetrating 35 in. of unbacked wrought +iron at a distance of 1,000 yards. The projectile fired from the 67 +ton guns of the Empress of India will have much less penetrating +power, being only equal to 27 in. of wrought iron with a full charge +of 520 lb. of prismatic brown powder, the missile weighing 1,250 lb. +or about one-half less than the weight of the shot used with the 110 +ton gun. It will thus be seen that the ordnance of the Benbow can +penetrate armor that would defy the attack of the guns of the Empress. +It should be said, however, that the heavy artillery of the latter +vessel is capable of penetrating any armor at present afloat, and is +carried at a much greater height above the designed load water line +than in any existing battle ship, either in the British or foreign +navies. The armor being of less weight, too, enables the new ship, and +others of her class, to carry an auxiliary armament of unprecedented +weight and power. + +The Empress will be lighted throughout by electricity, the +installation comprising some 600 lights, and will be provided with +four 25,000 candle power search lights, each of which will be worked +by a separate dynamo. The ship has been built from the designs of Mr. +W.H. White, C.B., Director of Naval Construction, and will be fitted +out for the use of an admiral, and when commissioned her complement of +officers and men will number 700.--_Industries._ + + * * * * * + + + + +THE "IRON GATES" OF THE DANUBE. + + +The work of blowing up the masses of rock which form the dangerous +rapids known as the Iron Gates, on the Danube, was inaugurated on +September 15, 1890, when the Greben Rock was partially blown up by a +blast of sixty kilogrammes of dynamite, in the presence of Count +Szapary, the Hungarian premier; M. Baross, Hungarian minister of +commerce; Count Bacquehem, Austrian minister of commerce; M. Gruitch, +the Servian premier; M. Jossimovich, Servian minister of public works; +M. De Szogyenyi, chief secretary in the Austro-Hungarian ministry of +foreign affairs; and other Hungarian and Servian authorities. Large +numbers of the inhabitants had collected on both banks of the Danube +to witness the ceremony, and the first explosion was greeted with +enthusiastic cheers. The history of this great scheme was told at the +time the Hungarian Parliament passed the bill on the subject two years +ago. It is known that the Roman Emperor Trajan, seventeen centuries +ago, commenced works, of which traces are still to be seen, for the +construction of a navigable canal to avoid the Iron Gates. + +For the remedy of the obstruction in the Danube, much discussed of +late years, there were two rival systems--the French, which proposed +to make locks, and the English and American, which was practically +the same as that of Trajan, namely, blasting the minor rocks and +cutting canals and erecting dams where the rocks were too crowded. The +latter plan was in principle adopted, and the details were worked out, +in 1883, by the Hungarian engineer Willandt. The longest canal will be +that on the Servian bank, with a length of over two kilometers and a +width of eighty meters. It will be left for a later period to make the +canal wider and deeper, as was done with the Suez Canal. For the +present it is considered sufficient that moderate sized steamers shall +be able to pass through without hindrance, and thus facilitate the +exchange of goods between the west of Europe and the east. + +The first portion of the rocks to be removed, and of the channels to +be cut, runs through Hungarian territory; the second portion is in +Servia. The new waterway will, it is anticipated, be finished by the +end of 1895, and then, for the first time in history, Black Sea +steamers will be seen at the quays of Pesth and Vienna, having, of +course, previously touched at Belgrade. The benefit to Servian trade +will then be quite on a par with that of Austria-Hungary. Even Germany +will derive benefit from this extension of trade to the east. These, +however, are by no means the only countries which will be benefited by +the opening of the great river to commerce. Turkey, Southern Russia, +Roumania, and Bulgaria, not to speak of the states of the west of +Europe, will reap advantage from this new departure. England, as the +chief carrier of the world, is sure to feel the beneficial effects of +the Danube being at length navigable from its mouth right up to the +very center of Europe. + +The removal of the Iron Gates has always been considered a matter of +European importance. The treaty of Paris stipulated for freedom of +navigation on the Danube. The London treaty of 1871 again authorized +the levying of tolls to defray the cost of the Danube regulation; and +article 57 of the treaty of Berlin intrusted Austria-Hungary with the +task of carrying out the work. By these international compacts the +European character of the great undertaking is sufficiently attested. + +[Illustration: THE "IRON GATES" OF THE DANUBE] + +The work of blasting the rocks will be undertaken by contractors in +the employ of the Hungarian government, as the official invitation for +tenders brought no offers from any quarter. The construction of the +dams, however, and the cutting of several channels to compass the most +difficult rocks and rapids, will be carried out by an association of +Pesth and other firms. The cost, estimated altogether at nine million +florins, will be borne by the Hungarian exchequer, to which will fall +the tolls to be levied on all vessels passing through the Gates until +the original outlay is repaid. + +Very few persons know, says the _American Architect_, what an enormous +work has been undertaken at the Iron Gates of the Danube, where +operations are rapidly progressing, mainly in accordance with a plan +devised many years ago by our distinguished countryman, Mr. McAlpine. +The total length of that part of the river to be regulated is about +two hundred and fifty miles, so that the enterprise ranks with the +cutting of the Panama and Suez canals as one of the greatest +engineering feats ever attempted. Work has been begun simultaneously +at three points: at Greben, where there are reefs to be taken care of; +at the cataract, near Jucz, and at the Iron Gate proper, below Orsova. +At Greben, where the stream is shallow, but swift, a channel two +hundred feet wide is to be blasted out of the rock, and below it a +stone embankment wall is to be built more than four miles long. From a +reef which projects into the river a piece is to be blasted away, +measuring five hundred feet in length, and about nine feet in depth. +The difficulties of working in this part of the river are very great. +Not only is the current extremely rapid, but in certain places ridges +of rock barely covered at low water alternate with pools a hundred +and forty feet deep, which give rise, in the rapid current, to +frightful whirlpools and eddies. These deep pools are to be filled at +the same time that the reefs are cut away, and it is estimated that +nearly three million cubic feet of loose stonework will be needed for +this purpose alone. In addition to the excavation, artificial banks +and breakwaters, for modifying the course of the stream, are to be +built; so that it is estimated that the masonry to be executed in this +section will amount to about five and one-half million cubic feet. + +In the cataract section, at Jucz, a channel two hundred feet wide, and +more than half a mile long, is to be blasted out of the rock, and a +breakwater built, to moderate the suddenness of the fall. This +breakwater is to be about two miles long, and ten feet thick at the +top, increasing in thickness toward the bottom. The rock in which the +channel must be cut at this point is partly serpentine greenstone, +partly chrome iron ore, and is intensely hard. In the section of the +Iron Gate, the work to be done consists in "canalizing" the river for +a distance of a mile and a half, by building a wall on each side, and +excavating the bed of the river between. The channel between the walls +will be two hundred and fifty feet wide. It is estimated that nearly +three million cubic feet of rock will have to be excavated here, all +of which will be used to fill in behind the embankment walls. Of +course, the greater part of the rock will be removed by means of +blasting with high explosives, but some of it is to be attacked with a +novel instrument, which was first tried, on a small scale, on the +Panama Canal, and is to be used for serious work here. This +instrument, as it is to be employed on the Danube, consists of an +enormous steel drill, thirty-three feet long, and weighing ten tons. +By means of a machine like a pile driver, this monstrous tool is +raised to a height of about fifty feet, and allowed to drop, point +first. So heavy a mass of metal, falling from a considerable height, +meets with comparatively little resistance from the water, and the +point shatters and grinds up the rock on which it strikes. Fifty or +sixty blows per minute can be struck with a tool of this kind, and ten +thousand blows in all can be inflicted before the tool is so worn as +to be past service. Several of these drills will be at work at the +same time, and to remove the fragments of rock which they break off, a +huge dredge of three hundred and fifty horse power is to be employed. +For excavating by means of explosives, arrangements have been made for +drilling the holes for the cartridges with the greatest possible +rapidity, as on this depends the celerity with which the work can be +pushed forward. Much of the work will be done by means of diamond +drills, which are mounted on boats. Five of these boats have been +provided, each with seven diamond drills, arranged so as to work +perfectly in twenty feet of water. Other boats are fitted with +pneumatic drills, which are operated by means of air, compressed to a +tension of seven hundred and fifty pounds to the square inch. The +pressure of the compressed air is transmitted by means of water to the +drills, which act by percussion, and work very rapidly. These drills +are curiously automatic in their operation. After boring the holes to +the allotted depth, the machine automatically sets in each a tube, +washes out the dust, inserts a dynamite cartridge, withdraws the tube, +and connects the wire of the electric fuse in the cartridge with the +battery wire in the boat. The cartridges are charged with a pound of +dynamite to each. In hard rock only one charge is fired at a time, but +in softer material four are fired at once. If the water over the work +is deep, the boat is not moved from its position, but in shallow water +it is towed a few yards away from the spot where the explosion is to +take place. The drill holes are about six feet deep, and are spaced at +the rate of about one to every three square feet, something, of +course, depending upon the character of the rock. The whole work is +now under contract, the mechanical engineering firm of Luther, of +Brunswick, having undertaken to complete it in five years, for a +payment of less than four million dollars. + + * * * * * + + + + +THE NEW GERMAN SHIP CANAL. + + +The gates which admit the water into the new canal which is to connect +the Baltic with the North Sea have been recently opened by the Emperor +William. This canal is being constructed by the German government +principally for the purpose of strengthening the naval resources of +Germany, by giving safer and more direct communication for the ships +of the navy to the North German ports. The depth of water will be +sufficient for the largest ships of the German navy. The canal will +also prove of very great advantage to the numerous timber and other +vessels trading between St. Petersburg, Stockholm, Dantzic, Riga, and +all the North German ports in the Baltic and this country. The passage +by the Kattegat and Skager Rack is exceedingly intricate and very +dangerous, the yearly loss of shipping being estimated at half a +million of money. In addition to the avoidance of this dangerous +course, the saving in distance will be very considerable. Thus, for +vessels trading to the Thames the saving will be 250 miles, for those +going to Lynn or Boston 220, to Hull 200, to Newcastle or Leith 100. +This means a saving of three days for a sailing vessel going to Boston +docks, the port lying in the most direct line from the timber ports of +the Baltic to all the center of England. The direction of the canal is +shown by the thick line in the accompanying sketch map of the North +Sea and Baltic. Considering that between 30,000 and 40,000 ships now +pass through the Sound annually, the advantage to the Baltic trade is +very apparent. + +[Illustration: THE NEW GERMAN SHIP CANAL.] + +The new canal starts at Holtenau, on the north side of the Kiel Bay, +and joins the Elbe fifteen miles above the mouth. From Kiel Bay to +Rendsborg, at the junction with the Eider, the new canal follows the +Schleswig and Holstein Canal, which was made about one hundred years +ago, and is adapted for boats drawing about eight feet; thence it +follows the course of the Eider to near Willenbergen, when it leaves +that river and turns southward to join the Elbe at Brunsbuttel, about +forty miles below Hamburg. The canal is 61 miles long, 200 ft. wide at +the surface, and 85 ft. at the bottom, the depth of water being 28 ft. +The surface of the water in the two seas being level, no locks are +required; sluices or floodgates only being provided where it enters +the Eider and at its termination. The country being generally level +there are no engineering difficulties to contend with, except a boggy +portion near the Elbe; the ground to be removed is chiefly sandy loam. +Four railways cross the canal and two main roads, and these will be +carried across on swing bridges. The cost is estimated at L8,000,000. +About six thousand men are employed on the works, principally Italians +and Swiss.--_The Engineer._ + + * * * * * + + + + +THE KIOTO-FU CANAL, IN JAPAN. + + +Japan is already traversed by a system of railways, and its population +is entering more and more into the footsteps of western civilization. +This movement, a consequence of the revolution of 1868, is extending +to the public works of every kind, for while the first railway lines +were being continued, there was in the course of excavation (among +other canals) a navigable canal designed to connect Lake Biwa and the +Bay of Osaka, upon which is situated Kioto, the ancient capital of +Japan. + +The work, which was begun in 1885, was finished last year, and one of +our readers has been kind enough to send us, along with some +photographs which we herewith reproduce, a description written by Mr. +S. Tanabe, engineer in chief of the work. + +The object of the Kioto-Fu Canal is not only to provide a navigable +watercourse, putting the interior of the country in connection with +the sea, but also to furnish waterfalls for supplying the water works +of the city of Kioto with the water necessary for the irrigation of +the rice plantations, and that employed for city distribution. It +starts from the southwest extremity of Lake Biwa, the largest lake in +Japan, and the area of which is 800 square kilometers. This lake, +which is situated at 84 meters above the level of the sea, is 56 +kilometers from the Bay of Osaka. As this bay is already in +communication with Kioto by a canal, the Kioto-Fu forms a junction +with the latter after a stretch of 11 kilometers and a difference of +level of 45 meters between its extremities. + +[Illustration: FIG. 1.--EXTREMITY OF LAKE BIWA AND BEGINNING OF THE +CANAL.] + +The lake terminates in a marshy plain (Fig. 1), in which the first +excavation was made. This is protected by longitudinal dikes which +lead back the water to it in case of freshets. At the end of this +cutting, which is 100 meters in length, begins the canal properly so +called, with a width of 5.7 meters, at the surface, and a depth of 1.5 +meters, for a length of 540 meters. It then reaches the first tunnel +for crossing the Nagara-yama chain. This tunnel is 2,500 meters in +length, 4.8 in width and 4.2 in height. The water reaches a depth of +1.8 meters upon the floor. It was pierced through very varied +materials, such as clay, schists, sandstone and porphyry, and is lined +throughout with brick masonry. The construction was effected by means +of a working shaft 45 meters in depth, sunk in the axis of the work, +at a third of its length from the west side. At the upper extremity +are established sluices that permit of securing to the canal a +constant discharge of 8.5 cubic meters per second. Fig. 2 represents +the head of this work. + +[Illustration: FIG. 2.--HEAD OF THE PRINCIPAL TUNNEL.] + +Starting from the tunnel, the canal extends in the open air for a +length of 4,500 meters. To reach the basin of Kioto, it traverses the +Hino-oko-yama chain of hills, through two tunnels of the same section +and construction as the one just mentioned, and of the respective +lengths of 125 and 841 meters. Traction in the tunnels is to be +effected by means of an immersed chain. + +On leaving tunnel No. 3, at about 8,400 meters from its origin, the +canal divides into two branches. The first of these, which is designed +to serve as a navigable way, has a slope 0.066 per meter for a length +of 540 meters. It is a true inclined plane, which the boats pass over +by means of a cradle carried by trucks and drawn by a cable actuated +by the fall furnished by the other branch. At the foot of the inclined +plane, the canal widens out to 18 meters at the surface, with a depth +of 1.5 meter, and, through a sluice, joins the Osaka Bay Canal, after +a stretch of 2 kilometers. + +[Illustration: FIG. 3.--AQUEDUCT OVER THE VALLEY OF THE TOMBS OF THE +EMPERORS.] + +The second branch traverses a small tunnel, crosses the valley of the +emperors' tombs upon an aqueduct of 14 arches (Fig. 3), and reaches +Kogawa, a faubourg north of Kioto, after a stretch of 8 kilometers. +Its slope is greater than that of the main canal, from which it +derives but 1.4 cubic meter. The 7 cubic meters remaining may be +employed for the production of motive power under a fall of 56 meters. +It is proposed to utilize a portion of it, at the point of bifurcation +and at the top of the inclined plane, in a hydraulic installation that +will drive electric machines. The total cost of the work was one +million dollars, a third of which was furnished by the imperial +treasury, a quarter by the central government, and the rest by various +taxes.--_La Nature._ + + * * * * * + + +HOW TO FIND THE CRACK.--Most mechanics know that by drilling a hole at +the inner end of a crack in cast metal its extension can be prevented. +But to find out the exact point where the crack ends, the _Revue +Industrielle_ recommends moistening the cracked surface with +petroleum, then, after wiping it, to immediately rub it with chalk. +The oil that has penetrated into the crack will, by exudation, +indicate the exact course and end of the crack. + + * * * * * + + + + +FAST AND FUGITIVE DYES.[1] + + [Footnote 1: A paper recently read before the Society of Arts, + London.] + +By Prof. J.J. HUMMEL. + + +As it is with many other arts, the origin of dyeing is shrouded in the +obscurity of the past; but no doubt it was with the desire to attract +his fellow that man first began to imitate the variety of color he saw +around him in nature, and colored his body or his dress. + +Probably the first method of ornamenting textile fabrics was to stain +them with the juices of fruits, or the flowers, leaves, stems, and +roots of plants bruised with water, and we may reasonably assume that +the primitive colors thus obtained would lack durability. + +By and by, however, it was found possible to render some of the dyes +more permanent, probably in the first instance by the application of +certain kinds of earth or mud, as we know to be practiced by the Maori +dyers of to-day, and in this way, as it appears to me, the early dyers +learnt the efficacy of what we now call "mordants," which I may +briefly describe as fixing agents for coloring matters. + +At a very remote period therefore, I imagine, the subject of fast and +fugitive dyes engaged the attention of textile colorists. + +Our European knowledge of dyeing seems to have come to us from the +East, and although at first indigenous dyestuffs were largely +employed, with the discovery of new countries many of these fell +slowly and gradually into disuse, giving way to the newly imported +dyestuffs of other lands, which possessed some advantage, being either +richer in coloring matter, yielding brighter or faster colors, or +being capable of more easy application. Thus kermes gave way to +cochineal, woad to indigo, and so on. + +Down to about the year 1856, natural dyestuffs alone, with but one or +two exceptions, were employed by dyers; but in that year a present +distinguished member of this Society, Dr. Perkin, astonished the +scientific and industrial world by his epoch-making discovery of the +coal tar color mauve. From that time down to the present, the textile +colorist has had placed before him an ever increasing number of +coloring matters derived from the same source. + +Specially worthy of notice are the discoveries of artificial alizarin, +in 1868, by Graebe and Liebermann, and of indigotin, in 1878, by Adolf +Baeyer, both coloring matters being identical with the respective dyes +obtained from plants. + +In view of the vast array of coal tar colors now at our disposal, and +their almost universal application in the decoration of all manner of +textile fabrics, threatening even the continued use of well known +dyestuffs of vegetable origin, it becomes of the greatest importance +to examine most thoroughly, and to compare the stability of both old +and new coloring matters. + +The first point in discussing this question of fast and fugitive dyes +is to define the meaning of these terms "fast" and "fugitive." +Unfortunately, as frequently employed, they have no very definite +signification. The great variety of textile fabrics to which coloring +matters are applied, the different stages of manufacture at which the +coloring matter is applied, and the many uses to which the fabrics are +ultimately put, all these are elements which cause dyed colors to be +exposed to the most varied influences. + +The term a "fast color," then, may convey a different meaning to +different individuals. To one it implies that the color will not fade +when exposed to light and atmospheric conditions; to another that it +is not impoverished by washing with soap and water; to a third it may +indicate that the color will withstand the action of certain +manufacturing operations, such as scouring, milling, stoving, etc.; +while a fourth person might be so exacting as to demand that a fast +color should resist all the varied influences I have named. + +It is well to state at once that no dyed color is absolutely fast, +even to a single influence, and it certainly cannot pass unscathed +through all the operations to which it may be necessary to submit +individual colors applied to this or that material. Many colors are +fast to washing or milling, and yet very fugitive to light; others are +fast to light, but fugitive toward milling; while others again are +fast to both influences. In short, each color has its own special, +characteristic properties, so that colors may be classified with +respect to each particular influence, and may occupy a very different +rank in the different arrangements. + +It is, however, by no means necessary to demand absolute fastness from +any color. A color may "bleed" in milling, and therefore be very +unsuitable for tweeds, and yet be most excellent for curtains and +hangings, because of its fastness to light. So, too, a dye capable of +yielding rich or delicate tints, but only moderately fast to light, +may still be perfectly well adapted for the silks and satins of the +ball room, or even the rapidly changing fashion, although it would be +quite inadmissible for the pennon at the masthead. + +The colors of carpets, curtains, and tapestry should certainly be fast +to light, but no one expects them to undergo the fatigue of the weekly +washtub; and just as little as we look for the exposure of flannels +and hosiery, day by day and week by week, to the glare of sunlight, +much as we desire that the colors shall not run in washing. + +For all practical purposes, then, it seems reasonable to define a +"fast color" as one which will not be materially affected by those +influences to which, in the natural course of things, it will be +submitted. Hence, in speaking of a fast color, it becomes necessary to +refer specially to the particular influences which it resists before +the term acquires a definite meaning. To be precise, one should say +that a color is "fast to light," or "fast to washing," or "fast to +light and washing," and so on. Further, it is necessary, as we shall +see afterward, to give always the name of the fiber to which the color +is applied. + +All that I have said with respect to the term "fast" may be applied +with equal propriety to the term "fugitive." This, too, has no very +definite meaning until a qualifying statement, such as I have referred +to, gives it precision. + +The most important question to be considered is + + +THE ACTION OF LIGHT ON DYED COLORS. + +That light can effect radical changes in many substances was known to +the ancients. Its destructive action on artists' pigments, e.g., the +blackening of vermilion, was recorded 2,000 years ago by Vitruvius. +Since that time it has been well established, by numerous observations +and experiments, that light possesses, in a high degree, the power of +exerting chemical action, i.e., causing the combination or +decomposition of a large number of substances. The union of chlorine +with hydrogen gas, the blackening of silver salts, the reduction of +bichromate of potash and of certain ferric salts in contact with +organic substances, are all familiar instances of the action of light. +In illustration of this, I show here some calico prints produced by +first preparing the calico with a solution of potassium bichromate, +then exposing the dried calico under a photographic negative, and, +after washing, dyeing with alizarin or some similar coloring matter. +During the exposure under the negative, the light has reduced and +fixed the chromium salt upon certain parts of the fiber as insoluble +chromate of chromium (Cr_{2}O_{3}CrO_{3}) in the more protected +portions, the bichromate remains unchanged, and is subsequently +removed by washing. During the dyeing process, the coloring matter +combines with the chromium fixed on the fiber, and thus develops the +colored photograph. + +The prints in Prussian blue are produced in a similar manner, the +sensitive salt with which the calico is prepared being ammonium +ferricitrate, and the developer potassium ferricyanide. + +Investigation has shown that the most chemically active rays are those +situated at the blue end of the solar spectrum; and although all the +rays absorbed by a sensitive colored body affect its change, it is +doubtless the blue rays which are the chief cause of the fading of +colors. Experiments are on record, indeed, which prove this. + +Depierre and Clouet (1878-82) exposed a series of colors, printed and +dyed on calico, to light which had passed through glasses stained red, +orange, yellow, green, blue, and violet, corresponding to definite +parts of the spectrum. They found that the blue light possessed the +greatest fading power, red light the least. + +More recently (1886-88) Abney and Russell exposed water colors under +red, green, and blue glass, and came to the same conclusion. + +But the chemical energy of the sun's rays is not the sole cause of the +fading of colors. There are certain contributory causes as important +as the light itself. + +About fifty years ago, Chevreul showed what these accessory causes +are, by exposing to light a number of dyed colors under varied +conditions, e.g., in a vacuum, in dry and moist hydrogen, dry and +moist air, water vapor, and the ordinary atmosphere. He found that +such fugitive colors as orchil, safflower, and indigo-carmine fade +very rapidly in moist air, less rapidly in dry air, and that they +experience little or no change in hydrogen or in a vacuum. The general +conclusion arrived at was, that light, when acting alone, i.e., +without the aid of air and moisture, exercises a very feeble +influence. Further, it was determined that the air and moisture, +without aid of light, have also comparatively little effect on dyed +colors. Abney and Russell, in their experiments with water colors, +obtained similar results. + +These conclusions are exactly in accordance with our common knowledge +of the old fashioned method of bleaching cotton and linen, in which +the wetted fabric is exposed to light on the grass, and frequently +sprinkled with water. If the material becomes dry through the absence +of dew or rain, or the want of sprinkling, little or no bleaching +takes place. + +The one color which Chevreul found to behave abnormally was Prussian +blue. This faded even in a vacuum; but, strange to say, on keeping the +faded color in the dark, and exposed to air, the color was restored. +It was shown that, during the exposure to light, the color lost +cyanogen, or hydrocyanic acid, while in the dark and exposed to the +air, oxygen was absorbed. Chevreul concluded, therefore, that the +fading of Prussian blue was due to a process of reduction. + +The prevailing opinion, however, is that the fading of colors is a +process of oxidation, caused by the ozone, or hydrogen peroxide, which +is probably formed in small quantity during the evaporation of the +moisture present, and both these substances are powerful bleaching +agents. + +It would be extremely convenient to have some rapid method of testing +colors for fastness to light, and I believe it is the custom with some +to apply certain chemical tests with this object in view. The results +of my own experiments in this direction lead me to the conclusion that +at present we have no sufficient substitute for sunlight for this +purpose, since I have not found any oxidizing or reducing substance +which affects dyed colors in all respects like the natural +color-fading agencies; further, I am inclined to the opinion that the +action of light varies somewhat with the different coloring matters, +according to their chemical constitution and the fiber upon which they +are applied. + +With respect to this last point, Chevreul actually found that colors +are faster to light on some fibers than on others, and this fact, +which is generally known to practical men, is abundantly shown in the +diagrams on the wall. As a rule we may say that colors are most +fugitive on cotton and most permanent on wool, those on silk holding +an intermediate position. Still there are many exceptions to this +order, especially as between silk and wool. + +Since the time of Chevreul, the action of light on dyed colors has not +been seriously and exhaustively studied. From time to time, series of +patterns dyed with our modern colors have been exposed to light, e.g., +by Depierre and Clouet, Joffre, Muller, Kallab, Schmidt, and others; +but the published results must at best be considered as more or less +fragmentary. Under the auspices of the British Association, and a +committee appointed at its last meeting in Leeds, I hope to have the +pleasure during the next few years of studying this interesting +subject. + +To-night I propose to give you some of the prominent results already +obtained in past years, in the dyeing department of the Yorkshire +College, where it has been our custom to expose to light and other +influences the patterns dyed by our students. Further, I wish to give +you an ocular demonstration of the action of light or dyed colors, by +means of these silk, wool, and cotton patterns, portions of which have +been exposed for 34 days and nights on the sea coast near Bombay, +during the month of February of this year. + +I may remark that this test has been a very trying one, for I estimate +that it is equal to more than a year's exposure in this country. +During the whole period there was cloudless sunshine, without any +rain, and each evening heavy dew. I have pleasure in acknowledging the +services of Mr. W. Reid, a former student, who superintended the +exposure of the patterns, and from time to time took notes of the rate +at which individual patterns faded. + +These diagrams contain, perhaps, the most complete series of both old +and new dyes, on the three fibers, which have been simultaneously +exposed to sunlight, and they form an instructive object lesson. + +Let me first direct your attention to the diagram containing the +_natural coloring matters_--those dyestuffs which were in use previous +to 1856. Broadly speaking, they are of two kinds; those which dye +textile materials "direct," and those which give no useful color +without the aid of certain metallic salts, called "mordants." + +Now, among the natural coloring matters, these "mordant dyes," as they +may be conveniently termed, are much more numerous than the "direct +dyes;" but be it observed, we have fast and fugitive colors in both +classes. + +Referring first to the wool patterns and to the "direct dyes," we find +that the only really fast colors are Prussian blue and Vat indigo +blue. Turmeric, orchil, catechu, and indigo carmine are all extremely +fugitive. + +As to the "mordant dyes," some yield fast colors with all the usual +mordants, e.g., madder, cochineal, lac dye, kermes, viz., reds with +tin and aluminum, claret browns with copper and chromium, and dull +violets with iron. + +Other dyestuffs, like camwood, brazilwood, and their allies, also +young fustic, give always fugitive colors whatever mordant be +employed; others again, e.g., weld, old fustic, quercitron bark, +flavin, and Persian berries, give fast colors with some mordants and +fugitive colors with others; compare, for example, the fast olives of +the chromium, copper, and iron mordants with the fugitive yellows +given by aluminum and tin. A still more striking case is presented by +logwood, which gives a fast greenish-black with copper and very +fugitive colors with aluminum and tin. Other experiments have shown +that the chromium and iron logwood blacks hold an intermediate +position. Abnormal properties are found to be exhibited by camwood and +its allies, with aluminum and tin, the colors at first becoming +darker, and only afterward fading in the normal manner. + +When we examine the silk patterns, we find, generally speaking, a +similar degree of fastness among the various natural dyes, as with +wool; in some instances the colors appear even faster, notice, for +example, the catechu brown and the colors given by brazilwood and its +allies, with iron mordant. + +On examining the cotton patterns, we are at once struck with the +marked fugitive character of nearly all the natural dyes. The +exceptions are: the madder colors, especially when fixed on +oil-prepared cotton, as in Turkey red; the black produced by logwood, +tannin, and iron; and a few mineral colors, e.g., iron buff, manganese +brown, chromate of lead orange, etc., and Prussian blue. Cochineal and +its allies, which are such excellent dyes for wool and silk, give only +fugitive colors on cotton. + +The main point which arrests our attention in connection with the +natural dyes seems to me to be the comparatively limited number of +fast colors. Very remarkable is the total absence of any really fast +yellow vegetable dye, and it is probably on this account that gold +thread was formerly so much introduced into textile fabrics. Notice +further the decided fastness of Prussian blue, especially on wool and +silk; while we cannot but remark the comparatively fugitive character +of vat indigo blue on cotton, and even on silk, compared with the +fastness of the same color when fixed on wool. + +Now, let us turn our attention to the _artificial coloring matters_, +derived with few exceptions from coal tar products. + +Here again we have two classes, "mordant dyes" and "direct dyes." Both +classes are somewhat numerous, but whereas the former may be +conveniently shown on a single diagram sheet, it requires a +considerable number to display the latter. + +First let us examine the wool patterns dyed with the "mordant dyes." + +We find there a few yellow dyes quite equal in fastness to those of +natural origin, or even somewhat surpassing them, e.g., two of the +alizarin yellows, viz., those marked R and G G W. Except in point of +fastness and mode of application, I may say that these are not true +alizarin colors, neither are they analogous to the natural yellow +dyestuffs, for they are incapable of giving dark olives with iron +mordants. Truer representatives of the natural yellow dyes appear, +however, to exist in galloflavin and the alizarin yellows marked A and +C, and, as you see, they are of about the same degree of fastness. + +Among the red dyes we have alizarin and its numerous allies, and these +are certainly fit representatives of the madder root, which indeed +they have almost entirely displaced. The most recent additions to this +important class are the various alizarin Bordeaux. The only dyes in +this group which appear somewhat behind the rest in point of fastness +are purpurin and alizarin maroon. + +On this same diagram we notice, also, fast blues and dark greens, of +which we have no similar representatives among the natural coloring +matters. I refer to alizarin blue, alizarin cyanin, alizarin indigo, +alizarin green, and coerulin. + +Further, an excellent group of coloring matters, giving fast browns +and greens with copper and iron mordants respectively, is formed by +naphthol green, resorcinol green, gambin, and dioxin. + +The only fugitive dyes of the class now under consideration are some +of the yellows, gallamin blue and gallocyanin. + +If we now turn to examine the colors given by these artificial +"mordant dyes" on silk, we notice, also, a good series of fast colors +similar to those which they give on wool; and even on cotton we see +many fast colors, of which we have no representatives among the +dyewoods. + +If we were not prepared to find so few really fast natural dyes, +surely we cannot but be surprised to find what a considerable number +of fast dyes are to be met with among the coal tar coloring matters +requiring the aid of mordants. + +On these diagrams, the first vertical column shows the stain given by +the coloring matter alone; the remaining columns show the colors +obtained when the same coloring matters are applied in conjunction +with the several mordants--chromium, aluminum, tin, copper, and iron. + +It was formerly held that the office of a mordant was merely to fix +the coloring matter upon the fiber; we now know, however, and it is +plainly illustrated by these diagrams, that this view is erroneous, +for the mordant not only fixes but also develops the color; the +mordant and coloring matter chemically combine with each other, and +the resultant compound represents the really useful pigment or dye. If +a coloring matter is combined with different mordants, the dyes thus +obtained represent distinct chemical products, and it is quite +natural, therefore, to find them differing from each other in color, +and their resistance toward light. + +Knowing this, it is clearly the duty of the dyer to apply each +coloring matter of this class with a variety of mordants, and to +select the particular combination which gives him the desired color +and fastness. By adopting this method, however, his selection would +ultimately comprise a large number of coloring matters paired with a +great variety of mordants. In order, therefore, to avoid the intricacy +involved in the use of several mordants, and to simplify the process +of dyeing, especially when dyeing compound shades, the dyer prefers to +limit himself as far as possible to the use of a single mordant, and +to employ along with it a mixture of several coloring matters. + +Now the woolen dyer has largely adopted an excellent mordant in +bichromate of potash; it is cheap, easily applied, and not perceptibly +injurious to the fiber. It is his desire, therefore, to have a good +range of red, yellow, blue, and other coloring matters, all giving +fast dyes with this mordant. This action and desire on the part of the +dyer has more and more placed the problem of producing fast colors +upon the shoulders of the color manufacturer or chemist, and right +well has the demand been met, for in the diagram on the wall we see +how, in the alizarin colors and their allies, he has already furnished +the dyer with a goodly number of dyestuffs yielding fast dyes with +this chosen mordant of the woolen dyer. Since, however, they yield +fast colors with other useful mordants, and upon other fibers than +wool, these alizarin colors prove of the greatest value to the dyer of +textile fabrics generally. Let us not forget the fact, then, that it +is among the "mordant dyes," the very class to which belong most of +the natural coloring matters, that we find our fastest coal tar dyes. + +When we examine the results of actual exposure experiments, such as +are here shown on these four diagram sheets, surely we have no +hesitation in declaring how utterly false is the popular opinion that +all coal tar colors are fugitive to light, while the good +old-fashioned natural dyes are all fast. The very opposite indeed is +here shown to be the case. For myself, I feel persuaded that at the +present time the dyer has at his command a greater number of fast dyes +derived from coal tar than from any other source, and I believe it +possible to produce with dyes obtained from this source alone, if need +be, tapestries, rugs, carpets, and other textile fabrics which shall +vie successfully in point of color and duration of color with the best +productions of the East, either of this or any other age. + +How, then, does it happen that these coal tar colors have been so long +and so seriously maligned by the general public? Apart from the fact +that public opinion has been based upon an imperfect knowledge of the +subject, we shall find a further explanation when we examine the +diagrams showing the "direct dyes" obtained from coal tar. According +to their mode of application I have here arranged them in three large +groups, viz., basic, acid, and Congo colors. A fourth group, +comprising comparatively few, is made up of those colors which are +directly produced upon the fiber itself. + +The "basic colors" have a well known type in magenta. They are usually +applied to wool and silk in a neutral or slightly alkaline bath; on +cotton they are fixed by means of tannate of antimony or tin. The +"acid colors" are only suitable for wool and silk, to which they are +applied in an acid bath. A typical representative of this group is +furnished by any one of the ordinary azo scarlets which in recent +years have come into prominence as competitors of cochineal. The +"Congo colors" are comparatively new, and are conveniently so named +from the first coloring matter of the group which was discovered, +viz., Congo red. They are applicable to wool, silk, and cotton, +usually in a neutral or slightly alkaline bath. Of the dyes produced +directly upon the fiber itself, one may take aniline black and also +primulin as a type, the latter a dye somewhat recently introduced by +Mr. A.G. Green, of this city. + +Our first impression, in looking at these "direct dyes," is that they +are more numerous and more brilliant than the "mordant dyes," and that +they are for the most part fugitive. Still, if we examine the +different series in detail, we shall find here and there, on the +different fibers, colors quite equal in fastness to any of the +"mordant dyes." + +Among the "basic colors" we search in vain, however, for a really fast +dye on any fiber. Still, Magdala red, perhaps, appears faster than the +rest on silk, and among the greens and blues we find a few dull blues +on cotton, which, for this fiber, have been recommended as substitutes +for indigo, viz., Indophenin, paraphenylene, blue, cinerein, Meldola's +blue, etc. The azine greens, also, appear tolerably fast on cotton and +on silk, but although possessing some body of color, after exposure, +the original dark green has changed to a decided drab. + +When we examine the "acid colors," however, we meet with a number of +scarlets, crimsons, and clarets, possessing considerable fastness both +on wool and on silk. Some, indeed, appear almost, if not entirely, as +fast as cochineal scarlet, e.g., Biebriech scarlet, brilliant crocein, +etc. + +Among the "acid oranges and yellows," we also find a goodly number +which are of medium fastness. About ten, either on wool or on silk, +may even be accounted really fast, and are fit, apparently, to rank +with alizarin colors. Note, for example, on wool: Crocein orange, +aurantia, orange crystal, tartrazin, milling yellow, palatine orange; +on silk, acid yellow D, brilliant yellow, azo acid yellow, metanil +yellow, curcumin S, etc. I may remark that these are some of the +fastest yellows on wool and silk with which we are acquainted. It is +interesting to note the decided fugitive character, on silk, of +tartrazin, aurantia, orange crystal, etc., compared with their great +fastness on wool. Observe, also, how, on wool, the pale lemon yellow +of picric acid has changed to a full reddish brown. + +Among the "acid greens and blues," all the colors are fugitive, both +on wool and on silk. Patent blue appears slightly better than the +rest. Of the "acid blacks and violets," a few colors are of medium +fastness, both on wool and silk, e.g., naphthol black, naphthylamine, +black, resorcinol brown, fast brown, etc. + +When we examine the Congo colors, amid a number of very fugitive +colors, we find a few which are satisfactorily fast. Among the reds, +for example, diamine fast red is quite remarkable for its fastness, +both on wool and silk, and may certainly rank with alizarin; but on +cotton, it is quite as fugitive as the rest. Of medium fastness on +wool are brilliant Congo G and R, Congo G R; and on silk, diamine +scarlet B, deltapurpurin 5 B, and brilliant Congo R. + +Among the "Congo oranges and yellows," we find some of the fastest on +cotton of this class of colors. Still they deserve only the rank of +medium fastness. They are Mikado orange 4 R, R, G. Hessian yellow, +curcumin S, chrysophenin. On wool, we have about half a dozen of +medium fastness, viz., benzo-orange, Congo orange R, chrysophenin G, +chrysamin R, brilliant yellow. On silk, however, we find in this group +about a dozen of the fastest oranges and yellows with which we are +acquainted for this fiber, viz., Congo orange R, chrysophenin G, +diamine yellow N, brilliant yellow, curcumin W, benzo orange, Hessian +yellow, chrysamin R and G, cresotin yellow R and G, cotton yellow G, +and carbazol yellow. + +Does it not appear somewhat remarkable that we should find among this +generally fugitive group of coloring matters colors which are so +eminently fast on silk, and which we entirely fail to meet with among +those groups which usually furnish our fast colors, e.g., the alizarin +group? + +Passing on to the "Congo violets, blues, and purples," we find few +colors worthy of particular notice for fastness. Diamine violet N +appears, perhaps, of medium fastness on wool and silk, while +sulphonazurin, benzo-black blue, and direct gray may claim the same +distinction on silk. + +In the small group of colors which are produced directly upon the +fiber, none seems to call for special notice, except aniline black, +which, notwithstanding its direct derivation from aniline, is probably +the fastest color we have upon any fiber. + +Now, in classifying the whole range of coal tar coloring matters into +"mordant dyes" and "direct dyes," and the latter into acid, basic, +Congo colors, etc., I have looked at them from the point of view of +the dyer and arranged them according to color and mode of application. +The chemist, however, classifies them quite differently, viz., +according to their chemical constitution, i.e., the arrangement of the +atoms of which they are composed, and thus we have nitro colors, +phthaleins, azines, and so on. + +In studying the action of light on the coal tar colors from this point +of view, we find that whereas the members of some groups are for the +most part fugitive, the members of other groups are nearly all fast, +and it becomes at once apparent that the chemical constitution of a +coloring matter exercises a profound influence upon its behavior +toward light. Members of the rosaniline group are all similarly +fugitive, while those of the alizarin group possess generally the +quality of fastness. Particularly fugitive are the eosins, and yet +some of these, by a slight modification of constitution, e.g., the +introduction of an ethyl group, as in ethyl-eosin, are rendered +distinctly faster. + +In the azo group some colors are fugitive, others are moderately fast, +and it is generally recognized that certain classes of the tetrazo +compounds are distinctly faster than the ordinary diazo colors. + +By a careful study of the influence of the atomic arrangement upon the +stability of colors, information useful to the color manufacturer may +possibly be gained, but at present my facts are not yet sufficiently +tabulated to enable one to recognize any generally pervading law in +this direction. + +It is scarcely necessary to say that the fastness to light of a color +is independent of its commercial value, this being mainly determined +by the price of the raw material from which it is manufactured, the +working expenses, and the profit desired by the manufacturer. Neither +must we suppose that facility of application necessarily interferes +with its fastness to light, for some of our fastest coal tar colors on +wool, e.g., diamine fast red, tartrazin, etc., are applied in the +simplest possible manner. On the other hand, the intensity or depth of +a color has considerable influence on its fastness. Dark full shades +invariably appear faster than pale ones produced from the same +coloring matter, simply because of the larger body of pigment present. +A pale shade of even a very fast color like indigo will fade with +comparative rapidity. The fugitive character of many of the coal tar +colors is, in my opinion, rendered more marked, because, owing to +their intense coloring power, there is often such an infinitesimal +amount of coloring matter on the dyed fiber. Hence it is that in the +Gobelin tapestries pale shades on wool are frequently obtained by the +use of more or less unchangeable metallic oxides and other mineral +colors, to the exclusion of even fast vegetable dyes. + +It is interesting to examine what is the action of light upon compound +colors. Is a fugitive color rendered faster by being applied along +with a fast color? + +My own opinion, based upon general observation, is that it is not, and +that when light acts upon a compound color the unstable color fades, +while the stable color remains behind. A woaded color, for example, is +only fast in respect of the vat indigo which it contains, and yet how +frequent is the custom to unite with the indigo such dyes as barwood, +orchil, and indigo-carmine, the fugitive character of which I have +pointed out. + +Having thus rapidly surveyed these numerous coal tar colors, both in +their dyed and exposed conditions, I again ask why are they so +generally regarded as altogether fugitive? + +First, because we have, especially among these "direct dyes," a very +large number which are undoubtedly very fugitive. + +Moreover, all the earlier coal tar dyes--mauve, magenta, Nicholson +blue, etc., belonged to a class which, even up to the present time, +has only furnished us with fugitive colors. They were indeed prepared +from aniline, and it appears to me that the defects of these early +aniline colors, as well as their designation, have been handed down to +their successors without due discrimination, so that in the popular +mind the term "aniline color" has become, as a matter of habit, +synonymous with "fugitive color." But science is progressive, fields +of investigation other than aniline have been opened up, so that now, +although a large number of fugitive dyes are still manufactured from +coal tar, there are others, as we have seen, which are as fast and +permanent as we have ever had from natural sources. + +Finally, and perhaps this is the most important cause of all, many of +the fugitive coal tar colors are gifted, I will not say with fatal +beauty, but with a facility of application, and such comparative +cheapness in consequence of their intense coloring power, that the +dyer, tempted by competition, applies them not unfrequently to +materials for which, because of their ultimate uses, they are +altogether unsuited; and so it comes about that we find the most +fugitive colors applied indiscriminately and without due discretion. + +As we look upon these multitudinous colors, one other thought cannot +fail to cross our minds. Is there not surely an overproduction of +these fugitive coal tar colors? Is not the dyer bewildered with an +_embarras de richesses_, so that he knows not where to choose? + +There is indeed much truth in this. With rare skill and ingenuity an +army of chemists is busy elaborating these wonderful dyes; but in such +quick succession are they introduced into the dye house that the busy +dyer has no time sufficiently to prove them, and it is not surprising +therefore that he is liable to commit errors in their application. + +But if there is an over-production of fugitive colors, there is also +at work, as in the organic world around us, the counteracting +influence of the law of the survival of the fittest. Sooner or later, +the fugitive colors must give way to those which are more permanent, +and already the number of coal tar colors which have been discarded, +for one reason or another, is considerable. + +Not unfrequently one is asked the question, Is there no method whereby +these fugitive colors can be made fast? Knowing the efficacy of +mordants with certain coloring matters, is there no mordant which we +can generally apply with this desirable object in view? The discovery +of such a universal mordant I believe to be somewhat chimerical, and +yet, curiously enough, a number of experiments have been recorded in +recent years, which almost seem to point in the direction of selecting +for such a purpose ordinary sulphate of copper. + +Some of these diagrams before you this evening show clearly the +fastness to light generally of the lakes formed with copper mordant. +This peculiarity of the copper compounds has not escaped the notice of +other observers. Dr. Schunck, for example, during the progress of his +research on chlorophyl, noticed the very permanent green dye which +this otherwise fugitive coloring matter gives in combination with +copper. + +Then there is the assertion of practical dyers, that the use of copper +sulphate in dyeing catechu brown on cotton assists materially in +rendering this color fast to light. + +The use of copper mordant with phenolic coloring matters is perfectly +natural. Some time ago, however, it was successfully applied, for the +purpose of rendering more permanent, to certain of the Congo colors on +cotton, e.g., benzo-azurine, etc., in the application of which, +metallic salts had not hitherto been deemed necessary. + +Noelting and Herzberg have also observed that the fastness to light, +even of basic colors, e.g., magenta, methyl violet, malachite green, +etc., is increased by a subsequent treatment of the dyed fabric with +copper sulphate solution, although in many cases the color is much +soiled thereby. + +Still more recently, A. Scheurer records that by impregnating or +padding certain dyed fabrics with an ammoniacal solution of copper +sulphate, the colors gain considerably in fastness to light. As the +result of his experiments Scheurer concludes that this protective +influence of copper on dyed colors is a general fact, apparently +applicable to all colors; that it is not necessarily due to its action +as a lake-forming substance, since intimate union between the coloring +matter and the copper salt is not necessary. He seems rather inclined +to ascribe its efficacy to the light being deprived of its active rays +during its passage through the oxide of copper. + +Knowing, however, the strong reducing action of light in many cases, +and with the absence of positive knowledge concerning the cause of the +fading of colors, it seems to me that the beneficial influence of the +copper may just as probably be due to its well known oxidizing power, +which counteracts the reducing action of the light. + +It is interesting to note, in connection with Scheurer's view, that, +many years ago, Gladstone and Wilson (1860) proposed to impregnate +colored materials with some colorless fluorescent substance, e.g., +sulphate of quinine, evidently with the idea of filtering off the +active ultra-violet rays. How far some such method as this might prove +successful I cannot say, but since we cannot keep our dyed textile +materials in a vacuum, as Chevreul did, nor is it desirable to +impregnate them with mastic varnish for the purpose of excluding air +and moisture, as Mr. Laurie proposes, in order to preserve the colors +of oil paintings, it is perhaps well to bear in mind the principle +here alluded to as a possible solution of the difficulty. + +I have dwelt rather long on this important question of the action of +light on dyed colors, but I have done so because I thought it would +most interest you. With the remaining portions of my subject I must be +more brief. + +(_To be continued._) + + * * * * * + + +To introduce free fat acids from an oil, it must be decomposed. This +may be done by the use of lead oxide and water or by analogous +processes. To clarify an oil, expose to the sun in leaden trays. Often +washing with water will answer the purpose. + + * * * * * + + + + +COMPOSITION OF WHEAT GRAIN AND ITS PRODUCTS IN THE MILL. + + +Probably the most striking difference in the average mineral +composition of the grain of wheat is the very much lower proportion of +phosphoric acid, and of magnesia also, in the dry substance of the +best matured grain; and it is now known that these characteristics +point to a less proportion of bran to flour, or, in other words, of a +greater accumulation of starch in the process of ripening, and +consequently of a whiter and better quality of bakers' flour. The +study of the chemical composition of wheat and its products in the +mill, therefore, and of the amount of fertilizing matters (nitrogen, +phosphoric acid and potash) removed from the soil by the crop, becomes +of direct interest not only to the producer from whose soil these +ingredients are removed, but to the consumer of the byproducts as +well, who desires to know what proportion of these elements of +fertility he is returning to his own soil in the different products he +may use as animal food. It is desirable also to determine what is the +average composition of wheats and the flour made from them, in order +to see in what direction efforts should be turned, by the selection of +seed wheats, to improve the present varieties for the production of +the best quality of flour. This can only be done after we determine +what variation there is for different years due to climatic influences +and variations of soil, for it has been shown in our former papers +that environment very largely influences the quality of wheat grain, +and also of the flour. When these have been determined, than we may +hope to be able to determine which factors under our control enter in +to permanently improve the better flour-producing quality of wheats. + +A mixture, in equal proportions, was made of Clawson, Mediterranean, +and early amber wheats, and submitted to the mill, using the Hungarian +roller process. From this mixture for each one bushel of the grain of +60 lb. weight was furnished the following proportion of products: + + Lb. per + Bushel. Per cent. + Flour. 44 73.3 + Middlings. 4 6.7 + Shipstuff. 2 3.3 + Bran. 10 16.7 + -- ----- + Total. 60 100.0 + + +These data furnish us a means of estimating the amount of the +different ingredients removed in the various products in one bushel of +wheat with the foregoing component parts. + + +FLOUR. + +The analysis of the flour shows us that the 44 lb. obtained from the +one bushel of grain would contain the following ingredients: + + Lb. per Bushel + of Wheat. + Water. 5.834 + Ash. 0.167 + Albuminoids. 4.620 + Woody fiber. 0.532 + Carbo-hydrates (starchy matters). 33.391 + Fat. 0.453 + + +WHEAT MIDDLINGS. + +The middlings form the inner coating of the wheat grain, next the +floury or starchy portion, and contain particles of the germ and a +larger percentage of carbohydrates than either shipstuff or bran, and +a less proportion of fiber, while the percentage of albuminoids +usually stands between that of shipstuff and bran. The following data +are obtained from the 4 lb. procured from a bushel of wheat: + + Lb. per Bushel + of Wheat. + Water. 0.562 + Ash. 0.138 + Albuminoids. 0.657 + Woody fiber. 0.142 + Carbo-hydrates (starchy matters). 2.307 + Fat. 0.193 + + +SHIPSTUFF. + +That part separated and known as shipstuff is a very thin layer next +outside of the middlings, and contains the germ not found in the +middlings or left as a part of the flour. The quantity produced, 2 lb. +from a bushel of wheat, is very small and rarely kept separate from +the bran. The following shows the analysis: + + Lb. per Bushel + of Wheat. + Water. 0.282 + Ash. 0.101 + Albuminoids. 0.349 + Woody fiber. 0.160 + Carbo-hydrates (starchy matters). 1.088 + Fat. 0.099 + + +BRAN. + +Bran, the outer coating of the wheat, contains twice or three times as +much fiber as does either of the other products from wheat, and +proportionately less of each of the other ingredients except ash, +which is greater, perhaps partly due to foreign matter adhering to the +kernel. The following analysis shows the amount of constituents +removed by the bran (10 lb.) from one bushel of wheat: + + Lb. per Bushel + of Wheat. + Water. 1.459 + Ash. 0.506 + Albuminoids. 1.416 + Woody fiber. 1.000 + Carbo-hydrates (starchy matters). 5.277 + Ash. 0.342 + +From the foregoing milling products obtained from one bushel of wheat +of 60 lb. in weight, the ash on analysis gave the following +constituents, which shows the amount that was abstracted from the soil +by its growth: + + _____________________________________________________ + | + CONSTITUENTS FROM ONE BUSHEL OF WHEAT. | + _____________________________________________________| + | | | | | + |Nitrogen.|Phosphoric| Potash. | Lime. | + | | Acid. | | | + | | | | | + +---------+----------+---------+---------+ + | | | | | + Flour. | 0.739 | 0.092 | 0.054 | 0.013 | + Middlings. | 0.105 | 0.064 | 0.024 | 0.002 | + Shipstuff. | 0.056 | 0.044 | 0.021 | 0.003 | + Bran. | 0.228 | 0.251 | 0.083 | 0.012 | + +---------+----------+---------+---------+ + Totals. | 1.118 | 0.454 | 0.182 | 0.030 | + ____________|_________|__________|_________|_________| + + +Or we may express the results in another form, the amount contained in +one ton of straw, and the products of 30 bushels of wheat, which may +be reckoned as an average crop, expressing the amounts in pounds as +follows: + + + AMOUNTS OF SELECTED CONSTITUENTS IN THIRTY + BUSHELS OF WHEAT AND ITS PROPORTION OF + STRAW. + _____________________________________________________ + | | | | | + |Nitrogen.|Phosphoric| Potash. | Lime. | + | | Acid. | | | + | | | | | + +---------+----------+---------+---------+ + | | | | | + Straw. | 11.20 | 2.67 | 13.76 | 6.20 | + Flour. | 22.17 | 2.76 | 1.62 | 0.39 | + Middlings. | 3.15 | 2.01 | 0.72 | 0.06 | + Shipstuff. | 1.68 | 1.32 | 0.63 | 0.09 | + Bran. | 6.84 | 7.53 | 2.49 | 0.36 | + +---------+----------+---------+---------+ + Totals. | 45.04 | 16.29 | 19.22 | 7.10 | + ____________|_________|__________|_________|_________| + + +From numerous investigations it has been found that in regard to the +nitrogen and the ash constituents, there is striking evidence of the +much greater influence of season than of manuring on the composition +of a ripened wheat plant, and especially of its final product--the +seed. Further, under equal circumstances the mineral composition of +the wheat grain, excepting in cases of very abnormal exhaustion, is +very little affected by different conditions as to manuring, provided +only that the grain is well and normally ripened. Again, it is found +that the composition may vary very greatly with variations of season, +that is, with variations in the conditions of seed formation and +maturation, upon which the organic composition of the grain depends. +In other words, differences in the mineral composition of the ripened +grain are associated with differences in its organic composition, and +hence the great value of proper selection both for seed and for +milling purposes. + + +AMERICAN WHEATS. + +In a comprehensive treatise on the composition of American wheats, Mr. +Clifford Richardson says we cannot attribute the poverty of American +wheats in nitrogen as a whole to an enhanced starch formation, and for +the following reasons: An enhanced formation of starch, there being no +poverty of nitrogen in the soil, increases the weight of the grain and +diminishes the relative percentage of nitrogen. Were this the cause of +the relatively low percentage of nitrogen in the American wheats, the +grain from the Eastern States, which are poorest in this respect, +would be heavier than those from the middle West, which are richer in +albuminoids; but this is not the case. Formation of starch is +attributed by Messrs. Lawes & Gilbert to the higher ripening +temperature in America, but Clifford Richardson has found that there +is scarcely any difference in composition or weight between wheats +from Canada and Alabama, and if anything those from Canada contain +more starch than those from the South, and the spring wheat from +Manitoba with its colder climate more than those from Dakota and +Minnesota, with its milder temperature. In Oregon is found a striking +example of the formation of starch and increase in the size of the +grain, at the relative expense of the nitrogen, due to climate, but +not to high ripening temperature. The average weight per hundred +grains of wheat from this State has been found to be 5.044 grains, and +the relative percentage of nitrogen 1.37, equivalent to 8.60 per cent. +of albuminoids. These are the extremes for America, and are due, as +has been said, to the enhanced formation of starch. This, however, is +said to be not owing to high ripening temperature, because most of the +specimens examined were grown west of the Cascade Range, which has an +extremely moist climate and a summer heat not exceeding 82 deg. F. for +any daily mean. The climate in another way, however, is, of course, +the cause, by producing luxuriant growth, as illustrated by all the +vegetation of the country. Numerous other analyses form illustrations +of the important effect of surroundings and season upon the storing up +of starch by the plant, and consequent relative changes in the +composition of the grain. + +As a whole, the poverty of American wheats in nitrogen, decreasing +toward the less exhausted lands of the West, seems to be due more to +influences of soil than of climate, while locally the influence of +season is found to be greater than that of manure, confirming the +conclusions of Messrs. Lawes & Gilbert. Also from the analyses of the +ash of different parts of the grain, as from the analyses of roller +milling products, we learn that a large percentage of ash +constituents, other things being equal, is indicative of large +proportion of bran, and consequently of a low percentage of +flour.--_The Miller._ + + * * * * * + + + + +PRECIOUS AND ORNAMENTAL STONES AND DIAMOND CUTTING.[1] + + [Footnote 1: Abstract from Census Bulletin No. 49, April, 1891.] + +By GEORGE FREDERICK KUNZ. + + +The statistics of this report are divided into two sections: First, +the discoveries and finds of precious stones in the United States and +the mineral specimens sold for museums and private collections or for +bric-a-brac purposes; second, the diamond cutting industry. + + +DISCOVERIES OF PRECIOUS STONES. + +Up to the present time there has been very little mining for precious +or semi-precious stones in the United States, and then only at +irregular periods. It has been carried on during the past few years at +Paris, Maine; near Los Cerrillos, New Mexico; in Alexander County, +North Carolina, from 1881 until 1888; and on the Missouri River near +Helena, Montana, since the beginning of 1890. True beryls and garnets +have been frequently found as a by-product in the mining of mica, +especially in Virginia and North Carolina. Some gems, such as the +chlorastrolite, thomsonite, and agates of Lake Superior, are gathered +on beaches, where they have fallen from rock which has gradually +disintegrated by weathering and wave action. + +_Diamond._--A very limited number of diamonds have been found in the +United States. They are met with in well-defined districts of +California, North Carolina, Georgia, and recently in Wisconsin, but up +to the present time the discoveries have been rare and purely +accidental. + +_Sapphire._--Of the corundum gems (sapphire, ruby, and other colored +varieties), no sapphires of fine blue color and no rubies of fine red +color have been found. The only locality which has been at all +prolific is the placer ground between Ruby and Eldorado bars, on the +Missouri River, sixteen miles east of Helena, Montana. Here sapphires +are found in glacial auriferous gravels while sluicing for gold, and +until now have been considered only a by-product. Up to the present +time they have never been systematically mined. In 1889 one company +took the option on four thousand acres of the river banks, and several +smaller companies have since been formed with a view of mining for +these gems alone or in connection with gold. The colors of the gems +obtained, although beautiful and interesting, are not the standard +blue or red shades generally demanded by the public. + +At Corundum Hill, Macon County, North Carolina, about one hundred gems +have been found during the last twenty years, some of good blue color +and some of good red color, but none exceeding $100 in value, and none +within the past ten years. + +_Beryl Gems._--Of the beryl gems (emerald, aquamarine, and yellow +beryl) the emerald has been mined to some extent at Stony Point in +Alexander County, North Carolina, and has also been obtained at two +other places in the county. Nearly everything found has come from the +Emerald and Hiddenite mines, where during the past decade emeralds +have been mined and cut into gems to the value of $1,000, and also +sold as mineralogical specimens to the value of $3,000; lithia +emerald, or hiddenite, to be cut into gems, $8,500, and for +mineralogical specimens, $1,500; rutile, cut and sold as gems, $150, +and as specimens, $50; and beryl, cut and sold as gems, $50. + +At an altitude of 14,000 feet, on Mount Antero, Colorado, during the +last three years, material has been found which has afforded $1,000 +worth of cut beryls. At Stoneham, Maine, about $1,500 worth of fine +aquamarine has been found, which was cut into gems. + +At New Milford, Connecticut, a property was extensively worked from +October, 1885, to May, 1886, for mica and beryl. The beryls were +yellow, green, blue, and white in color, the former being sold under +the name of "golden beryl." No work has been done at the mine since +then. In 1886 and 1887 there were about four thousand stones cut and +sold for some $15,000, the cutting of which cost about $3,000. + +_Turquoise._--This mineral, which was worked by the Aztecs before the +advent of the Spaniards, and since then by the Pueblo Indians, and +largely used by them for ornament and as an article of exchange, is +now systematically mined near Los Cerrillos, New Mexico. Its color is +blue, and its hardness is fully equal to that of the Persian, or +slightly greater, owing to impurities, but it lacks the softness of +color belonging to the Persian turquoise. + +From time immemorial this material has been rudely mined by the +Indians. Their method is to pour cold water on the rocks after +previously heating them by fires built against them. This process +generally deteriorates the color of the stone to some extent, tending +to change it to a green. The Indians barter turquoise with the Navajo, +Apache, Zuni, San Felipe, and other New Mexican tribes for their +baskets, blankets, silver ornaments, and ponies. + +_Garnet and Olivine (Peridot)._--The finest garnets and nearly all the +peridots found in the United States are obtained in the Navajo Nation, +in the northwestern part of New Mexico and the northeastern part of +Arizona, where they are collected from ant hills and scorpion nests by +Indians and by the soldiers stationed at adjacent forts. Generally +these gems are traded for stores to the Indians at Gallup, Fort +Defiance, Fort Wingate, etc., who in turn send them to large cities in +the East in parcels weighing from half an ounce to thirty or forty +pounds each. These garnets, which are locally known as Arizona and New +Mexico rubies, are the finest in the world, rivaling those from the +Cape of Good Hope. Fine gems weighing from two to three carats each +and upward when cut are not uncommon. The peridots found associated +with garnets are generally four or five times as large, and from their +pitted and irregular appearance have been called "Job's tears." They +can be cut into gems weighing three to four carats each, but do not +approach those from the Levant either in size or color. + +_Gold Quartz._--Since the discovery of gold in California, compact +gold quartz has been extensively used in the manufacture of jewelry, +at one time to the amount of $100,000 per annum. At present, however, +the demand has so much decreased that only from five to ten thousand +dollars' worth is annually used for this purpose. + +In addition to the minerals used for cabinet specimens, etc., there is +a great demand for making clocks, inkstands, and other objects. + +_Quartz._--During the year 1887 about half a ton of rock crystal, in +pieces weighing from a few pounds up to one hundred pounds each, was +found in decomposing granite in Chestnut Hill township, Ashe County, +North Carolina. One mass of twenty and one-half pounds was absolutely +pellucid, and more or less of the material was used for art purposes. +This lot of crystal was valued at $1,000. + +In Arkansas, especially in Garland and Montgomery Counties, rock +crystals are found lining cavities of variable size, and in one +instance thirty tons of crystals were found in a single cavity. These +crystals are mined by the farmers in their spare time and sold in the +streets of Hot Springs, their value amounting to some $10,000 +annually. Several thousand dollars' worth are cut from quartz into +charms and faceted stones, although ten times that amount of paste or +imitation diamonds are sold as Arkansas crystals. + +Rose quartz is found in the granitic veins of Oxford County, Maine, +and in 1887, 1888, and 1889 probably $500 worth of this material was +procured and worked into small spheres, dishes, charms, and other +ornamental objects. + +The well-known agatized and jasperized wood of Arizona is so much +richer in color than that obtained from any other known locality that, +since the problem of cutting and polishing the large sections used for +table tops and other ornamental purposes was solved, fully $50,000 +worth of the rough material has been gathered and over $100,000 worth +of it has been cut and polished. This wood, which was a very prominent +feature at the Paris Exposition, promises to become one of our richest +ornamental materials. + +Chlorastrolite in pebbles is principally found on the inside and +outside shores of Rock Harbor, a harbor about eight miles in length on +the east end of Isle Royale, Lake Superior, where they occur from the +size of a pin head to, rarely, the size of a pigeon's egg. When larger +than a pea they frequently are very poor in form or are hollow in +fact, and unfit for cutting into gems. They are collected in a +desultory manner, and are sold by jewelers of Duluth, Petoskey, and +other cities, principally to visitors. The annual sale ranges from +$200 to $1,000. + +Thomsonite in pebbles occurs with the chlorastrolite at Isle Royal, +but finer stones are found on the beach at Grand Marais, Cook County, +Minnesota. Like the chlorastrolites, they result from the weathering +of the amygdaloid rock, in which they occur as small nodules, and in +the same manner are sold by jewelers in the cities bordering on Lake +Superior to the extent of $200 to $1,000 worth annually. + + +THE DIAMOND CUTTING INDUSTRY. + +In New York there are sixteen firms engaged in cutting and recutting +diamonds, and in Massachusetts there are three. Cutting has also been +carried on at times in Pennsylvania and Illinois, but has been +discontinued. The firms that were fully employed were generally the +larger ones, whose business consisted chiefly in repairing chipped or +imperfectly cut stones or in recutting stones previously cut abroad, +which, owing to the superior workmanship in command here, could be +recut at a profit, or in recutting very valuable diamonds when it was +desired, with the certainty that the work could be done under their +own supervision, thus guarding against any possible loss by exchange +for inferior stones. + +The industry employed 236 persons, of whom 69 were under age, who +received $148,114 in wages. Of the 19 establishments, 16 used steam +power. The power is usually rented. Foot power is only used in one +establishment. Three of the firms are engaged in shaping black +diamonds for mechanical purposes, for glass cutters and engravers, or +in the manufacture of watch jewels. + +The diamonds used in this industry are all imported, for, as already +stated, diamonds are only occasionally found in the United States. + +The importation of rough and uncut diamonds in 1880 amounted to +$129,207, in 1889 to $250,187, and the total for the decade was +$3,133,529, while in 1883 there were imported $443,996 worth, showing +that there was 94 per cent. more cutting done in 1889 than 1880, but +markedly more in 1882 and 1883. This large increase of importation is +due to the fact that in the years 1882 to 1885 a number of our +jewelers opened diamond cutting establishments, but the cutting has +not been profitably carried on in this country on a scale large enough +to justify branch houses in London, the great market for rough +diamonds, where advantage can be taken of every fluctuation in the +market and large parcels purchased, which can be cut immediately and +converted into cash; for nothing is bought and sold on a closer margin +than rough diamonds. + +There has been a remarkable increase in the importation of precious +stones in this country in the last ten years. The imports from 1870 to +1879, inclusive, amounted to $26,698,203, whereas from 1880 to 1889, +inclusive, the imports amounted to $87,198,114, more than three times +as much as were imported the previous decade. + + * * * * * + + + + +SOME EXPERIMENTS ON THE ELECTRIC DISCHARGE IN VACUUM TUBES.[1] + + [Footnote 1: From a recent communication made to the Physical + Society, London.] + +By Prof. J.J. THOMSON, M.A., F.R.S. + + +[Illustration: FIG. 1.--Coil of Glass Tube for Vacuum Discharge +Experiments. The primary coils are filled with mercury, the secondary +coils form continuous closed circuits.] + +The phenomena of vacuum discharges were, he said, greatly simplified +when their path was wholly gaseous, the complication of the dark space +surrounding the negative electrode and the stratifications so commonly +observed in ordinary vacuum tubes being absent. To produce discharges +in tubes devoid of electrodes was, however, not easy to accomplish, +for the only available means of producing an electromotive force in +the discharge circuit was by electromagnetic induction. Ordinary +methods of producing variable induction were valueless, and recourse +was had to the oscillatory discharge of a Leyden jar, which combines +the two essentials of a current whose maximum value is enormous, and +whose rapidity of alternation is immensely great. + +[Illustration: FIG. 2.--Exhausted Bulb Surrounded by Primary Spiral +Consisting of a Coiled Glass Tube Containing Mercury.] + +[Illustration: FIG. 3.--Exhausted Bulb Surrounded by Primary Coils, +Inclosed in Bell Jar.] + +The discharge circuits, which may take the shape of bulbs, or of tubes +bent in the form of coils, were placed in close proximity to glass +tubes filled with mercury, which formed the path of the oscillatory +discharge. The parts thus corresponded to the windings of an induction +coil, the vacuum tubes being the secondary and the tubes filled with +the mercury the primary. In such an apparatus the Leyden jar need not +be large, and neither primary nor secondary need have many turns, for +this would increase the self-induction of the former and lengthen the +discharge path in the latter. Increasing self-induction of the primary +reduces the E.M.F. induced in the secondary, while lengthening the +secondary does not increase the E.M.F. per unit length. Two or three +turns (Fig. 1) in each were found to be quite sufficient, and on +discharging the Leyden jar between two highly polished knobs in the +primary circuit, a plain uniform band of light was seen to pass round +the secondary. An exhausted bulb (Fig. 2) containing traces of oxygen +was placed within a primary spiral of three turns, and, on passing the +jar discharge, a circle of light was seen within the bulb in close +proximity to the primary circuit, accompanied by a purplish glow, +which lasted for a second or more. On heating the bulb the duration of +the glow was greatly diminished, and it could be instantly +extinguished by the presence of an electromagnet. Another exhausted +bulb (Fig. 3), surrounded by a primary spiral, was contained in a bell +jar, and when the pressure of air in the jar was about that of the +atmosphere the secondary discharge occurred in the bulb, as is +ordinarily the case. On exhausting the jar, however, the luminous +discharge grew fainter, and a point was reached at which no secondary +discharge was visible. Further exhaustion of the jar caused the +secondary discharge to appear outside the bulb. The fact of obtaining +no luminous discharge either in the bulb or jar the author could only +explain on two suppositions, viz., that under the conditions then +existing the specific inductive capacity of the gas was very great, or +that a discharge could pass without being luminous. The author had +also observed that the conductivity of a vacuum tube without +electrodes increased as the pressure diminished until a certain point +was reached, and afterward diminished again, thus showing that the +high resistance of a nearly perfect vacuum is in no way due to the +presence of the electrodes. One peculiarity of the discharges was +their local nature, the rings of light being much more sharply defined +than was to be expected. They were also found to be most easily +produced when the chain of molecules in the discharge were all of the +same kind. For example, a discharge could be easily sent through a +tube many feet long, but the introduction of a small pellet of mercury +in the tube stopped the discharge, although the conductivity of the +mercury was much greater than that of the vacuum. In some cases he had +noticed that a very fine wire placed within a tube on the side remote +from the primary circuit would prevent a luminous discharge in that +tube. + +[Illustration: FIG. 4.--Exhausted Secondary Coil of One Loop +Containing Bulbs. The discharge passed along the inner side of the +bulbs, the primary coils being placed within the secondary.] + + * * * * * + + + + +THE ELECTRICAL MANUFACTURE OF PHOSPHORUS. + + +Dr. Readman, at the May meeting of the Glasgow Section of the Society +of Chemical Industry, gave a description of the new works and plant +which have been erected at Wolverhampton for the manufacture of +phosphorus by the Readman-Parker patents. The process consists in +decomposing the mixture of phosphoric acid, or acid phosphates and +carbon, by the heat of the electric arc embedded in the mass. + + * * * * * + + + + +LAYING A MILITARY FIELD TELEGRAPH LINE. + + +The 1st Division of the Royal Engineers, Telegraph Battalion, now +encamped at Chevening, close to Lord Stanhope's park, as a summer +exercise is engaged in running a military telegraph field line from +Aldershot to Chatham. Along the whole of the line the wire is +supported on light fir and bamboo poles. The work has been carried out +with unusual celerity. From Aldershot to Chevening, a distance of +fifty miles, the line was erected in a day and a quarter, or under +thirty hours, the detachments employed having worked or marched all +night. This is, it is said, the greatest length of telegraph line ever +laid within so short a time. The result cannot fail to be useful, for +by the new line communication is now established both by telegraph and +telephone between Aldershot and Chatham. For laying such telegraph +lines to accompany calvary, a light cable is made use of. This is +carried on reels on a wheeled cart, and can be laid at the rate of six +to seven miles an hour. The Telegraph Battalion of the Royal Engineers +comprises two divisions. One is employed in time of peace under the +Post Office in the construction and maintenance of postal lines; the +other, stationed at Aldershot, is equipped with field telegraph +material.--_Daily Graphic._ + +[Illustration: LAYING A MILITARY FIELD TELEGRAPH LINE.] + + * * * * * + + + + +AN ELECTROSTATIC SAFETY DEVICE. + + +This device, as shown in the accompanying illustration, is a glass +cylinder fixed on an ebonite base, and closed at the top by an ebonite +cap. A solid brass rod runs from top to bottom, and near the bottom, +and at right angles to it, is fixed a smaller adjustable rod, +terminating in a flat head. Opposite to this flat disk there is a +brass strip secured to the ebonite cap. From the top of this brass +strip hangs a gold or aluminum foil. The foil and strip are placed to +earth, and the solid brass rod is connected to the circuit to be +protected. Should the difference of potential between the foil and the +terminal opposite to it attain more than a certain amount, +electrostatic attraction will cause the foil to touch the disk and +place the circuit to earth. The apparatus, which is a modification of +the Cardew earthing device, is constructed by Messrs. Drake & Gorham, +of Victoria Street.--_The Electrician_. + +[Illustration.] + + * * * * * + + + + +EXPERIMENTS WITH HIGH TENSION ALTERNATING CURRENTS. + + +Messrs. Siemens and Halske, of Berlin, recently invited the members of +the Elektrotechnische Verein of that city to their works to witness +the demonstration of a series of experiments on alternating currents +under a pressure of 20,000 volts. In order to show that the desired +pressure was really _en evidence_, the high tension was conducted +through a pair of wires of only 0.2 mm. diameter to a battery of 200 +100-volt incandescent lamps, all connected up in series. An ordinary +Siemens electric light cable was inserted, and broke down at a +pressure of some 15,000 volts. + +At the end of the meeting a few experiments on the formation of the +arc under this enormous pressure were shown. The sparking distance +varied considerably, according to the shape of the electrodes. At +20,000 volts a spark jumped from a ball to a ball about 10 +millimeters, while between two points a sparking distance of 30 +millimeters, and sometimes even more, was reached. This arc is shown +half size in the accompanying engraving. + +[Illustration: A 20,000 VOLT ALTERNATING ARC (half size).] + +The arc which followed the jumping over of a spark made a loud humming +and clapping noise, and flapped about, being easily carried away by +the slightest draught. The arc could be drawn out horizontally to +something like 100 millimeters distance between the electrodes, and +even to a distance of 150 millimeters, when carbon pencils were used +as electrodes, but it always remained standing up in a point. +--_Electrical Engineer._ + + * * * * * + + + + +THE RELATION OF BACTERIA TO PRACTICAL SURGERY.[1] + + [Footnote 1: The address in surgery delivered before the Medical + Society of the State of Pennsylvania, June 4, 1890.] + +By JOHN B. ROBERTS, A.M., M.D., Professor of Surgery in the Woman's +Medical College and in the Philadelphia Polyclinic. + + +The revolution which has occurred in practical surgery since the +discovery of the relation of micro-organisms to the complications +occurring in wounds has caused me to select this subject for +discussion. Although many of my hearers are familiar with the germ +theory of disease, it is possible that it may interest some of them to +have put before them in a short address a few points in bacteriology +which are of value to the practical surgeon. + +It must be remembered that the groups of symptoms which were formerly +classed under the heads "inflammatory fever," "symptomatic fever," +"traumatic fever," "hectic fever," and similar terms, varying in name +with the surgeon speaking of them, or with the location of the +disease, are now known to be due to the invasion of the wound by +microscopic plants. These bacteria, after entering the blood current +at the wound, multiply with such prodigious rapidity that the whole +system gives evidence of their existence. Suppuration of wounds is +undoubtedly due to these organisms, as is tubercular disease, whether +of surgical or medical character. Tetanus, erysipelas, and many other +surgical conditions have been almost proved to be the result of +infection by similar microscopic plants, which, though acting in the +same way, have various forms and life histories. + +A distinction must be made between the "yeast plants," one of which +produces thrush, and the "mould plants," the existence of which, as +parasites in the skin, gives rise to certain cutaneous diseases. These +two classes of germs are foreign to the present topic, which is +surgery; and I shall, therefore, confine my remarks to that group of +vegetable parasites to which the term bacteria has been given. These +are the micro-organisms whose actions and methods of growth +particularly concern the surgeon. The individual plants are so minute +that it takes in the neighborhood of ten or fifteen hundred of them +grouped together to cover a spot as large as a full stop or period +used in punctuating an ordinary newspaper. This rough estimate applies +to the globular and the egg-shaped bacteria, to which is given the +name "coccus" (plural, cocci). The cane or rod shaped bacteria are +rather larger plants. Fifteen hundred of these placed end to end would +reach across the head of a pin. Because of the resemblance of these +latter to a walking stick they have been termed bacillus (plural, +bacilli). + +The bacteria most interesting to the surgeon belong to the cocci and +the bacilli. There are other forms which bacteriologists have dubbed +with similar descriptive names, but they are more interesting to the +physician than to the surgeon. Many micro-organisms, whether cocci, +bacilli, or of other shapes, are harmless, hence they are called +non-pathogenic, to distinguish them from the disease-producing or +pathogenic germs. + +As many trees have the same shape and a similar method of growing, but +bear different fruits--in the one case edible and in the other +poisonous--so, too, bacteria may look alike to the microscopist's eye, +and grow much in the same way, but one will cause no disease, while +the other will produce perhaps tuberculosis of the lungs or brain. + +Many scores of bacteria have been, by patient study, differentiated +from their fellows and given distinctive names. Their nomenclature +corresponds in classification and arrangement with the nomenclature +adopted in different departments of botany. Thus we have the +pus-causing chain coccus (streptococcus pyogenes), so-called because +it is globular in shape, because it grows with the individual plants +attached to each other, or arranged in a row like a chain of beads on +a string, and because it produces pus. In a similar way we have the +pus-causing grape coccus of a golden color (staphylococcus pyogenes +aureus). It grows with the individual plants arranged somewhat after +the manner of a bunch of grapes, and when millions of them are +collected together, the mass has a golden yellow hue. Again, we have +the bacillus tuberculosis, the rod-shaped plant which is known to +cause tuberculosis of the lungs, joints, brain, etc. + +It is hardly astonishing that these fruitful sources of disease have +so long remained undetected, when their microscopic size is borne in +mind. That some of them do cause disease is indisputable, since +bacteriologists have, by their watchful and careful methods, separated +almost a single plant from its surroundings and congeners, planted it +free from all contamination, and observed it produce an infinitesimal +brood of its own kind. Animals and patients inoculated with the plants +thus cultivated have rapidly become subjects of the special disease +which the particular plant was supposed to produce. + +The difficulty of such investigation becomes apparent when it is +remembered that under the microscope many of these forms of vegetable +life are identical in appearance, and it is only by observing their +growth when in a proper soil that they can be distinguished from each +other. In certain cases it is quite difficult to distinguish them by +the physical appearances produced during their growth. Then it is only +after an animal has been inoculated with them that the individual +parasite can be accurately recognized and called by name. It is known +then by the results which it is capable of producing. + +The various forms of bacteria are recognized, as I have said, by their +method of growth and by their shape. Another means of recognition is +their individual peculiarity of taking certain dyes, so that special +plants can be recognized, under the microscope, by the color which a +dye gives to them, and which they refuse to give up when treated with +chemical substances which remove the stain from, or bleach, all the +other tissues which at first have been similarly stained. + +The similarity between bacteria and the ordinary plants with which +florists are familiar is, indeed, remarkable. Bacteria grow in animal +and other albuminous fluids; but it is just as essential for them to +have a suitable soil as it is for the corn or wheat that the farmer +plants in his field. By altering the character of the albuminous fluid +in which the micro-organism finds its subsistence, these small plants +can be given a vigorous growth, or may be actually starved to death. +The farmer knows that it is impossible for him to grow the same crop +year after year in the same field, and he is, therefore, compelled to +rotate his crops. So it is with the microscopic plants which we are +considering. + +After a time the culture fluid or soil becomes so exhausted of its +needed constituents, by the immense number of plants living in it, +that it is unfit for their life and development. Then this particular +form will no longer thrive; but some other form of bacterium may find +in it the properties required for functional activity, and may grow +vigorously. It is probable that exhaustion or absence of proper soil +is an important agent in protecting man from sickness due to infection +from bacteria. The ever-present bacteria often gain access to man's +blood through external wounds, or through the lungs and digestive +tracts; but unless a soil suited for their development is found in its +fluids, the plants will not grow. If they do not grow and increase in +numbers, they can do little harm. + +Again, there are certain bacteria which are so antagonistic to each +other that it is impossible to make them grow in company, or to +co-exist in the blood of the same individual. For example, an animal +inoculated with erysipelas germs cannot be successfully inoculated +immediately afterward with the germs of malignant pustule. This +antagonism is illustrated by the impossibility of having a good crop +of grain in a field overrun with daisies. + +On the other hand, however, there are some micro-organisms which +flourish luxuriantly when planted together in the same fluid, somewhat +after the manner of pumpkins and Indian corn growing between the same +fence rails. Others seem unwilling to grow alone, and only flourish +when planted along with other germs. It is very evident, therefore, +that bacteriology is a branch of botany, and that nature shows the +same tendencies in these minute plants as it does in the larger +vegetable world visible to our unaided eyes. + +As the horticulturist is able to alter the character of his plants by +changing the circumstances under which they live, so can the +bacteriologist change the vital properties and activities of bacteria +by chemical and other manipulations of the culture substances in which +these organisms grow. The power of bacteria to cause pathological +changes may thus be weakened and attenuated; in other words, their +functional power for evil is taken from them by alterations in the +soil. The pathogenic, or disease producing, power may be increased by +similar, though not identical, alterations. The rapidity of their +multiplication may be accelerated, or they may be compelled to lie +dormant and inactive for a time; and, on the other hand, by exhausting +the constituents of the soil upon which they depend for life, they may +be killed. + +It is a most curious fact, also, that it is possible by selecting and +cultivating only the lighter colored specimens of a certain purple +bacterium for the bacteriologist to obtain finally a plant which is +nearly white, but which has the essential characteristics of the +original purple fungus. In this we see the same power which the +florist has to alter the color of the petals of his flowers by various +methods of selective breeding. + +The destruction of bacteria by means of heat and antiseptics is the +essence of modern surgery. It is, then, by preventing access of these +parasitic plants to the human organism (aseptic surgery), or the +destruction of them by chemical agents and heat (antiseptic surgery), +that we are enabled to invade by operative attack regions of the body +which a few years ago were sacred. + +When the disease-producing bacteria gain access to the tissues and +blood of human and other animals by means of wounds, or through an +inflamed pulmonary or alimentary mucous membrane, they produce +pathological effects, provided there is not sufficient resistance and +health power in the animal's tissues to antagonize successfully the +deleterious influence of the invading parasitic fungus. It is the +rapid multiplication of the germs which furnishes a _continuous_ +irritation that enables them to have such a disastrous effect upon the +tissues of the animal. If the tissues had only the original dose of +microbes to deal with, the warfare between health and disease would be +less uncertain in outcome. Victory would usually be on the side of the +tissues and health. The immediate cause of the pathogenic influence is +probably the chemical excretions which are given out by these +microscopic organisms. All plants and animals require a certain number +of substances to be taken into their organisms for preservation of +their vital activities. After these substances have been utilized +there occurs a sort of excretion of other chemical products. It is +probably the excretions of many millions of micro-organisms, +circulating in the blood, which give rise to the disease +characteristic of the fungus with which the animal has been infected. +The condition called sapraemia, or septic intoxication, for example, is +undoubtedly due to the entrance of the excretory products of +putrefaction bacteria into the circulation. This can be proved by +injecting into an animal a small portion of these products obtained +from cultures of germs of putrefaction. Characteristic symptoms will +at once be exhibited. + +Septicaemia is a similar condition due to the presence of the +putrefactive organisms themselves, and hence of their products, or +ptomaines, also in the blood. The rapidity of their multiplication in +this albuminous soil and the great amount of excretion from these +numerous fungi make the condition more serious than sapraemia. +Clinically, the two conditions occur together. + +The rapidity with which symptoms may arise after inoculation of small +wounds with a very few germs will be apparent, when it is stated that +one parasitic plant of this kind may, by its rapidity of +multiplication, give rise to fifteen or sixteen million individuals +within twenty-four hours. The enormous increase which takes place +within three or four days is almost incalculable. It has been +estimated that a certain bacillus, only about one thousandth of an +inch in length, could, under favorable conditions, develop a brood of +progeny in less than four days which would make a mass of fungi +sufficient to fill all the oceans of the world, if they each had a +depth of one mile. + +Bacteria are present everywhere. They exist in the water, earth, air, +and within our respiratory and digestive tracts. Our skin is covered +with millions of them, as is every article about us. They can +circulate in the lymph and blood and reach every tissue and part of +our organisms by passing through the walls of the capillaries. +Fortunately, they require certain conditions of temperature, moisture, +air, and organic food for existence and for the preservation of their +vital activities. + +If the surroundings are too hot, too cold, or too dry, or if they are +not supplied with a proper quantity and quality of food, the bacterium +becomes inactive until the surrounding circumstances change; or it may +die absolutely. The spores, which finally become full-fledged +bacteria, are able to stand a more unfavorable environment than the +adult bacteria. Many spores and adults, however, perish. Each kind of +bacterium requires its own special environment to permit it to grow +and flourish. The frequency with which an unfavorable combination of +circumstances occurs limits greatly the disease-producing power of the +pathogenic bacteria. + +Many bacteria, moreover, are harmless and do not produce disease, even +when present in the blood and tissues. Besides this, the white blood +cells are perpetually waging war against the bacteria in our bodies. +They take the bacteria into their interiors and render them harmless +by eating them up, so to speak. They crowd together and form a wall of +white blood cells around the place where the bacteria enter the +tissue, thus forming a barrier to cut off the blood supply to the +germs and, perhaps, to prevent them from entering the general blood +current. + +The war between the white blood cells and the bacteria is a bitter +one. Many bacteria are killed; but, on the other hand, the life of +many blood cells is sacrificed by the bacteria poisoning them with +ptomaines. The tissue cells, if healthy, offer great resistance to the +attacks of the army of bacteria. Hence, if the white cells are +vigorous and abundant at the site of the battle, defeat may come to +the bacteria; and the patient suffer nothing from the attempt of these +vegetable parasites to harm him. If, on the other hand, the tissues +have a low resistive power, because of general debility of the +patient, or of a local debility of the tissues themselves, and the +white cells be weak and not abundant, the bacteria will gain the +victory, get access to the general blood current, and invade every +portion of the organism. Thus, a general or a local disease will be +caused; varying with the species of bacteria with which the patient +has been affected, and the degree of resistance on the part of the +tissues. + +From what has been stated it must be evident that the bacterial origin +of disease depends upon the presence of a disease-producing fungus and +a diminution of the normal healthy tissue resistance to bacterial +invasion. If there is no fungus present, the disease caused by such +fungus cannot develop. If the fungus be present and the normal or +healthy tissue resistance be undiminished, it is probable that disease +will not occur. As soon, however, as overwork, injury of a mechanical +kind, or any other cause diminishes the local or general resistance of +the tissues and individual, the bacteria get the upper hand, and are +liable to produce their malign effect. + +Many conditions favor the bacterial attack. The patient's tissues may +have an inherited peculiarity, which renders it easy for the bacteria +to find a good soil for development; an old injury or inflammation may +render the tissues less resistant than usual; the point, at which +inoculation has occurred may have certain anatomical peculiarities +which make it a good place in which bacteria may multiply; the blood +may have undergone certain chemical changes which render it better +soil than usual for the rapid growth of these parasitic plants. + +The number of bacteria originally present makes a difference also. It +is readily understood that the tissues and white blood cells would +find it more difficult to repel the invasion of an army of a million +microbes than the attack of a squad of ten similar fungi. I have said +that the experimenter can weaken and augment the virulence of bacteria +by manipulating their surroundings in the laboratory. It is probable +that such a change occurs in nature. If so, some bacteria are more +virulent than others of the same species; some less virulent. A few of +the less virulent disposition would be more readily killed by the +white cells and tissues than would a larger number of the more +virulent ones. At other times the danger from microbic infection is +greater because there are two species introduced at the same time; and +these two multiply more vigorously when together than when separated. +There are, in fact, two allied hosts trying to destroy the blood cells +and tissues. This occurs when the bacteria of putrefaction and the +bacteria of suppuration are introduced into the tissues at the same +time. The former cause sapraemia and septicaemia, the latter cause +suppuration. The bacteria of tuberculosis are said to act more +viciously if accompanied by the bacteria of putrefaction. +Osteomyelitis is of greater severity, it is believed, if due to a +mixed infection with both the white and golden grape-coccus of +suppuration. + +I have previously mentioned that the bacteria of malignant pustule are +powerless to do harm when the germs of erysipelas are present in the +tissues and blood. This is an example of the way in which one species +of bacteria may actually aid the white cells, or leucocytes, and the +tissues in repelling an invasion of disease-producing microbes. + +Having occupied a portion of the time allotted to me in giving a crude +and hurried account of the characteristics of bacteria, let me +conclude my address by discussing the relation of bacteria to the +diseases most frequently met with by the surgeon. + +Mechanical irritations produce a very temporary and slight +inflammation, which rapidly subsides, because of the tendency of +nature to restore the parts to health. Severe injuries, therefore, +will soon become healed and cured if no germs enter the wound. + +Suppuration of operative and accidental wounds was, until recently, +supposed to be essential. We now know, however, that wounds will not +suppurate if kept perfectly free from one of the dozen forms of +bacteria that are known to give rise to the formation of pus. + +The doctrine of present surgical pathology is that suppuration will +not take place if pus-forming bacteria are kept out of the wound, +which will heal by first intention without inflammation and without +inflammatory fever. + +In making this statement I am not unaware that there is a certain +amount of fever following various severe wounds within twenty-four +hours, even when no suppuration occurs. This wound fever, however, is +transitory; not high; and entirely different from the prolonged +condition of high temperature formerly observed nearly always after +operations and injuries. The occurrence of this "inflammatory," +"traumatic," "surgical," or "symptomatic" fever, as it was formerly +called, means that the patient has been subjected to the poisonous +influence of putrefactive germs, the germs of suppuration, or both. + +We now know why it is that certain cases of suppuration are not +circumscribed but diffuse, so that the pus dissects up the fascias and +muscles and destroys with great rapidity the cellular tissue. This +form of suppuration is due to a particular form of bacterium called +the pus-causing "chain coccus." Circumscribed abscesses, however, are +due to one or more of the other pus-causing micro-organisms. + +How much more intelligent is this explanation than the old one that +diffuse abscesses depended upon some curious characteristic of the +patient. It is a satisfaction to know that the two forms of abscess +differ because they are the result of inoculation with different +germs. It is practically a fact that wherever there is found a diffuse +abscess there will be discovered the streptococcus pyogenes, which is +the name of the chain coccus above mentioned. + +So, also, is it easy now to understand the formation of what the old +surgeons called "cold" abscesses, and to account for the difference in +appearance of its puriform secretion from the pus of acute abscesses. +Careful search in the fluid coming from such "cold" abscesses reveals +the presence of the bacillus of tuberculosis, and proves that a "cold" +abscess is not a true abscess, but a lesion of local tuberculosis. + +Easy is it now to understand the similarity between the "cold abscess" +of the cervical region and the "cold abscess" of the lung in a +phthisical patient. Both of them are, in fact, simply the result of +invasion of the tissues with the ubiquitous tubercle bacillus; and are +not due to pus-forming bacteria. + +Formerly it was common to speak of the scrofulous diathesis, and +attempts were made to describe the characteristic appearance of the +skin and hair pertaining to persons supposed to be of scrofulous +tendencies. The attempt was unsuccessful and unsatisfactory. The +reason is now clear, because it is known that the brunette or the +blond, the old or the young, may become infected with the tubercle +bacillus. Since the condition depends upon whether one or the other +become infected with the generally present bacillus of tubercle, it is +evident that there can be no distinctive diathesis. It is more than +probable, moreover, that the cutaneous disease so long described as +lupus vulgaris is simply a tubercular ulcer of the skin, and not a +special disease of unknown causation. + +The metastatic abscesses of pyaemia are clearly explained when the +surgeon remembers that they are simply due to a softened blood clot +containing pus-causing germs being carried through the circulation and +lodged in some of the small capillaries. + +A patient suffering with numerous boils upon his skin has often been a +puzzle to his physician, who has in vain attempted to find some cause +for the trouble in the general health alone. Had he known that every +boil owed its origin to pus bacteria, which had infected a sweat gland +or hair follicle, the treatment would probably have been more +efficacious. The suppuration is due to pus germs either lodged upon +the surface of the skin from the exterior or deposited from the +current of blood in which they have been carried to the spot. + +I have not taken time to go into a discussion of the methods by which +the relationship of micro-organisms to surgical affections has been +established; but the absolute necessity for every surgeon to be fully +alive to the inestimable value of aseptic and antiseptic surgery has +led me to make the foregoing statements as a sort of _resume_ of the +relation of the germ theory of disease to surgical practice. It is +clearly the duty of every man who attempts to practice surgery to +prevent, by every means in his power, the access of germs, whether of +suppuration, putrefaction, erysipelas, tubercle, tetanus, or any other +disease, to the wounds of a patient. This, as we all know, can be done +by absolute bacteriological cleanliness. It is best, however, not to +rely solely upon absolute cleanliness, which is almost unattainable, +but to secure further protection by the use of heat and antiseptic +solutions. I am fully of the opinion that chemical antiseptics would +be needless if absolute freedom from germs was easily obtained. When I +know that even such an enthusiast as I myself is continually liable to +forget or neglect some step in this direction, I feel that the +additional security of chemical antisepsis is of great value. It is +difficult to convince the majority of physicians, and even ourselves, +that to touch a finger to a door knob, to an assistant's clothing, or +to one's own body, may vitiate the entire operation by introducing one +or two microbic germs into the wound. + +An illustration of how carefully the various steps of an operation +should be guarded is afforded by the appended rules, which I have +adopted at the Woman's Hospital of Philadelphia for the guidance of +the assistants and nurses. If such rules were taught every medical +student and every physician entering practice as earnestly as the +paragraphs of the catechism are taught the Sunday school pupil (and +they certainly ought to be so taught) the occurrence of suppuration, +hectic fever, septicaemia, pyaemia, and surgical erysipelas would be +practically unknown. Death, then, would seldom occur after surgical +operations, except from hemorrhage, shock, or exhaustion. + +I have taken the liberty of bringing here a number of culture tubes +containing beautiful specimens of some of the more common and +interesting bacteria. The slimy masses seen on the surfaces of jelly +contained in the tubes are many millions of individual plants, which +have aggregated themselves in various forms as they have been +developed as the progeny of the few parent cells planted in the jelly +as a nutrient medium or soil. + +With this feeble plea, Mr. President and members of the Society, I +hope to create a realization of the necessity for knowledge and +interest in the direction of bacteriology; for this is the foundation +of modern surgery. There is, unfortunately, a good deal of abominable +work done under the names of antiseptic and aseptic surgery, because +the simplest facts of bacteriology are not known to the operator. + +_Rules to be observed in Operations at Dr. Roberts' Clinic at the +Woman's Hospital of Philadelphia._--After wounds or operations high +temperature usually, and suppuration always, is due to blood +poisoning, which is caused by infection with vegetable parasites +called bacteria. + +These parasites ordinarily gain access to the wound from the skin of +the patient, the finger nails or hands of the operator or his +assistants, the ligatures, sutures, or dressings. + +Suppuration and high temperature should not occur after operation +wounds if no suppuration has existed previously. + +Bacteria exist almost everywhere as invisible particles in the dust; +hence, everything that touches or comes into even momentary contact +with the wound must be germ-free--technically called "sterile." + +A sterilized condition of the operator, the assistant, the wound, +instruments, etc., is obtained by removing all bacteria by means of +absolute surgical cleanliness (asepsis), and by the use of those +chemical agents which destroy the bacteria not removed by cleanliness +itself (antisepsis). + +Surgical cleanliness differs from the housewife's idea of cleanliness +in that its details seem frivolous, because it aims at the removal of +microscopic particles. Stains, such as housewives abhor, if germ-free, +are not objected to in surgery. + +The hands and arms, and especially the finger nails, of the surgeon, +assistants, and nurses should be well scrubbed with hot water and +soap, by means of a nail brush, immediately before the operation. The +patient's body about the site of the proposed operation should be +similarly scrubbed with a brush and cleanly shaved. Subsequently the +hands of the operator, assistants, and nurses, and the field of +operation should be immersed in, or thoroughly washed with, corrosive +sublimate solution (1:1,000 or 1:2,000). Finger rings, bracelets, +bangles, and cuffs worn by the surgeon, assistants, or nurses must be +removed before the cleansing is begun; and the clothing covered by a +clean white apron, large enough to extend from neck to ankles and +provided with sleeves. + +The instruments should be similarly scrubbed with hot water and soap, +and all particles of blood and pus from any previous operation removed +from the joints. After this they should be immersed for at least +fifteen minutes in a solution of beta-naphthol (1:2,500), which must +be sufficiently deep to cover every portion of the instruments. After +cleansing the instruments with soap and water, baking in a temperature +a little above the boiling point of water is the best sterilizer. +During the operation the sterilized instruments should be kept in a +beta-naphthol solution and returned to it when the operator is not +using them. + +[The antiseptic solutions mentioned here are too irritating for use in +operations within the abdomen and pelvis. Water made sterile by +boiling is usually the best agent for irrigating these cavities, and +for use on instruments and sponges. The instruments and sponges must +be previously well sterilized.] + +Sponges should be kept in a beta-naphthol or a corrosive sublimate +solution during the operation. After the blood from the wound has been +sponged away, they should be put in another basin containing the +antiseptic solution, and cleansed anew before being used again. The +antiseptic sutures and ligatures should be similarly soaked in +beta-naphthol solution during the progress of the operation. + +No one should touch the wound but the operator and his first +assistant. No one should touch the sponges but the operator, his first +assistant, and the nurse having charge of them. No one should touch +the already prepared ligatures or instruments except the surgeon and +his first or second assistants. + +None but those assigned to the work are expected to handle +instruments, sponges, dressings, etc., during the operation. + +When any one taking part in the operation touches an object not +sterilized, such as a table, a tray, or the ether towel, he should not +be allowed to touch the instruments, the dressings, or the ligatures +until his hands have been again sterilized. It is important that the +hands of the surgeon, his assistants, and nurses should not touch any +part of his own body, nor of the patient's body, except at the +sterilized seat of operation, because infection may be carried to the +wound. Rubbing the head or beard or wiping the nose requires immediate +disinfection of the hands to be practiced. + +The trailing ends of ligatures and sutures should never be allowed to +touch the surgeon's clothing or to drag upon the operating table, +because such contact may occasionally, though not always, pick up +bacteria which may cause suppuration in the wound. + +Instruments which fall upon the floor should not be again used until +thoroughly disinfected. + +The clothing of the patient, in the vicinity of the part to be +operated upon, and the blanket and sheets used there to keep him warm, +should be covered with dry sublimate towels. All dressings should be +kept safe from infection by being stored in glass jars, or wrapped in +dry sublimate towels. + + * * * * * + + + + +INFLUENCE OF REPOSE ON THE RETINA. + + +Some interesting researches have lately been published in an Italian +journal concerning the influence of repose on the sensitiveness of the +retina (a nervous network of the eye) to light and color. The +researches in question--those of Bassevi--appear to corroborate +investigations which were made some years ago by other observers. In +the course of the investigations the subject experimented upon was +made to remain in a dark room for a period varying in extent from +fifteen to twenty minutes. The room was darkened, it is noted, by +means of heavy curtains, through which the light could not penetrate. +After the eyes of the subject had thus been rested in the darkness, it +was noted that the sensitiveness of his sight had been increased +threefold. The mere sense of light itself had increased eighteen +times. It was further noted that the sensitiveness to light rays, +after the eye had been rested, was developed in a special order; the +first color which was recognized being red, then followed yellow, +while green and blue respectively succeeded. If color fatigue was +produced in the eye by a glass of any special hue, it was found that +the color in question came last in the series in point of recognition. +The first of these experiments, regarded from a practical point of +view, would appear to consist in an appreciation of the revivifying +power of darkness as regards the sight. The color purple of the retina +is known to become redeveloped in darkness; and it is probable, +therefore, that the alternation of day and night is a physical and +external condition with which the sight of animals is perfectly in +accord. + + * * * * * + + + + +SUN DIALS. + + +An article on the subject, recently published by us, has gained for us +the communication of two very interesting sun dials, which we shall +describe. The first, which we owe to the kindness of General Jancigny, +is of the type of the circular instrument, of which we explained the +method of using in our preceding article. The hour here is likewise +deduced from the height of the sun converted into a horary angle by +the instrument itself; but the method by which such conversion +operates is a little different. Fig. 1 shows the instrument open for +observation. We find here the meridian circle, M, and the equator E, +of the diagram shown in Fig. 3 (No. 4); but the circle with alidade is +here replaced by a small aperture movable in a slide that is placed in +a position parallel with the axis of the world. Upon this slide are +marked, on one side, the initials of the names of the months and on +the other side the corresponding signs of the zodiac. The sun +apparently describing a circle around the axis, PP¹, the rays passing +through a point of the axis (small aperture of the slide) will travel +over a circular cone around such axis. If, then, the apparatus be so +suspended that the circle, M, shall be in the meridian, the slide +parallel with the earth's axis, and the circle, E, at right angles +with the slide, the pencil of solar light passing through the aperture +will describe, in one day, a cone having the slide for an axis; that +is to say, concentric with the equator circle. If, moreover, the +aperture is properly placed, the luminous pencil will pass through the +equator circle itself; to this effect, the aperture should be in a +position such that the angle, a (Fig. 3, No. 4), may be equal to the +declination of the sun on the day of observation. It is precisely to +this end that the names of the months are inscribed upon the slide.... + +[Illustration: FIG. 1.--TRAVELER'S SUN DIAL.] + +The accessories of the instrument are as follows: A ring with a pivot +for suspending the meridian circle, and the position of which, given +by a division in degrees marked upon this circle, must correspond with +the latitude of the place; two stops serving to fix the position of +the equator circle; finally the latitude of various cities. The +instrument was constructed at Paris, by Butterfield, probably in the +last quarter of the eighteenth century. + +The second instrument, which is of the same nature as the cubical sun +dial--that is to say, with horary angle--is, unlike the latter, a true +trinket, as interesting as a work of art as it is as an astronomical +instrument. It is a little mandolin of gilded brass, and is shown of +actual size in Fig. 2. The cover, which is held by a hook, may be +placed in a vertical position, in which it is held by a second hook. +It bears in the interior the date 1612. This is the only explicit +historic datum that this little masterpiece reveals to us. Its maker, +who was certainly an artist, and, as we shall see, also a man of +science, had the modesty not to inscribe his name in it. + +[Illustration: FIG. 2.--SUN DIAL IN THE FORM OF A MANDOLIN, +CONSTRUCTED IN 1612.] + +No. 2 of Fig. 3 represents the instrument open. It rests upon the tail +piece and neck of the mandolin. The cover is exactly vertical. The +bottom of the mandolin is closed by a horizontal silver plate, +beneath which is soldered the box of a compass designed to put the +instrument in the meridian, and carrying upon its face an arrow and +the indications S. OR. M. OC., that is to say, "Septentrion" (north), +"Orient" (east), "Midi" (south), "Occident" (west). One of the ends of +the needle of the compass is straight, while the other is forked. It +is placed in a position in which it completes the arrow, thus +permitting of making a very accurate observation (Fig. 2, No. 3). +Around the compass, the silver plate carries the lines of hours. It is +perfectly adjusted, and held in place by a screw that traverses the +bottom of the instrument. In front of the compass it contains a small +aperture designed to permit of the passage of the indicating thread, +which, at the other end, is fastened to the cover. The silver plate is +not soldered, in order that the thread may be replaced when it chances +to break. On the inner part of the cover are marked in the first place +the horary lines, traversed by curves that are symmetrical with +respect to the vertical and having the aspect of arcs of hyperbolas. +At the extremity of these lines are marked the signs of the zodiac. At +the top, a pretty banderole, which appears at first sight to form a +part of the _ensemble_ of the curves, completes the design. Such is +this wonderful little instrument, in which everything is arranged in +harmonious lines that delight the eye and easily detract one's +attention from a scientific examination of it. Let us enter upon this +drier part of our subject; we shall still have room to wonder, and let +us take up first the higher question. + +[Illustration: FIG. 3.--DIAGRAM EXPLANATORY OF THE MANDOLIN SUN DIAL.] + +Let us consider a horizontal plane (Fig. 3, No. 2)--a plane +perpendicular to the meridian, and a right line parallel with the axis +of the world. Let P be a point upon this line. As we have seen, such +point is the summit of a very wide cone described in one day by the +solar rays. At the equinox this cone is converted into a plane, which, +in a vertical plane, intersects the straight line A B. Between the +vernal and autumnal equinoxes the sun is situated above this plane, +and, consequently, the shadow of P describes the lower curves at A B. +During winter, on the contrary, it is the upper curves that are +described. It is easily seen that the curves traced by the shadow of +the point P are hyperbolas whose convexity is turned toward A B. It +therefore appears evident to us that the thread of our sun dial +carried a knot or bead whose shadow was followed upon the curves. This +shadow showed at every hour of the day the approximate date of the day +of observation. The sun dial therefore served as a calendar. But how +was the position of the bead found? Here we are obliged to enter into +new details. Let us project the figure upon a vertical plane (Fig. 3, +No. 1) and designate by H E the summits of the hyperbolas +corresponding to the winter and summer solstices. If P be the position +of the bead, the angles, P H H¹, P E E¹, will give the height of the +sun above the horizon at noon, at the two solstices. Between these +angles there should exist an angle of 47 deg., double the obliquity of the +ecliptic, that is to say, the excursion of the sun in declination: now +P E E¹-P H H¹ = E P H = 47 deg.. + +Let us carry, at H and E, the angles, O H E = H E O = 43 deg. = 90 deg.-47 deg.; +the angle at 0 deg. will be equal to 180-86 = 94 deg.. If we trace the +circumference having O for a center, and passing through E and H, each +point, Q, of such circumference will possess the same property as the +angle, H Q E = 47 deg.. The intersection, P, of the circumference with the +straight line, N, therefore gives the position of the bead. + +Let us return to our instrument. We have traced upon a diagram the +distance of the points of attachment of the thread, at the +intersection of the planes of projection. We have thus obtained the +position of the line, N S. Then, operating as has just been said, we +have marked the point, P. Now, accurately measuring all the angles, we +have found: N S R = 50 deg.; P H H¹ = 18 deg.; P E E¹ = 65 deg.. The first shows +that the instrument has been constructed for a place on the parallel +of 50 deg., and the others show that, at the solstices, the height of the +sun was respectively 18 deg. and 65 deg., decompounded as follows: + + 18 deg. = polar height of the place -231/2 deg.. + 65 deg. = " " " " +231/2 deg.. + +The polar height of the place where the object was to be observed +would therefore be 411/2 deg., that is to say, its latitude would be 481/2 deg.. + +Minor views of construction and measurement and the deformations that +the instrument has undergone sufficiently explain the divergence of +11/2 deg. between the two results, which comprise between them the latitude +of Paris. + +After doing all the reasoning that we have just given at length, we +have finally found the means by which the hypothetic bead was to be +put in place. A little beyond the curves, a very small but perfectly +conspicuous dot is engraved--the intersection of two lines of +construction that it was doubtless desired to efface, but the scarcely +visible trace of which subsists. Upon measuring with the compasses the +distance between the insertion of the thread and this dot, we find +exactly the distance, N P, of our diagram. Therefore there is no doubt +that this dot served as a datum point. The existence of the bead upon +the thread and the use of it as a rude calendar therefore appears to +be certain. + +The compass is to furnish us new indications. After dismounting it--an +operation that the quite primitive enchasing of the face plate renders +very easy--we took a copy of it, which we measured with care. The +arrow forms with the line O C-O R an angle of 90 deg. + 8 deg.. The compass +was therefore constructed in view of an eastern declination of 8 deg.. + +Now, here is what we know with most certainty as to the magnetic +declination of Paris at the epoch in question: + + Years. Declinations. + 1550. 8 deg. east. + 1580. 11.30 + 1622. 6.30 + 1634. 4.16 + +On causing the curve (Fig. 3, No. 3) to pass through the four points +thus determined, we find, for 1612, the declination 81/2 deg.. This is, with +an approximation closer than that of the measurements that can be made +upon the small compass, the value that we found. From these data as a +whole we draw the two following conclusions: (1) The instrument was +constructed at Paris; and (2) the inventor was accurately posted in +the science of his time. + +Certain easily perceived retouchings, moreover, show that this sun +dial is not a copy, but rather an original. We are therefore in an +attitude to claim, as we did at the outset, that the constructor of +this pleasing object was not only an artist, but a man of science as +well. + +Let us compare a few dates: In 1612, Galileo and Kepler were still +living. Thirty years were yet to lapse before the birth of Newton. +Modern astronomy was in its tenderest infancy, and remained the +privilege of a few initiated persons.--_C.E. Guillaume, in La Nature._ + + * * * * * + +[MIND.] + + + + +THE UNDYING GERM PLASM AND THE IMMORTAL SOUL. + +By Dr. R. VON LENDENFELD. + +[The following article appeared originally, last year, in the German +scientific monthly, _Humboldt_. It, is reproduced here (by +permission)--the English from the hand of Mr. A.E. Shipley--as a +specimen of the kind of general speculation to which modern biology is +giving rise.--EDITOR.] + + +To Weismann is due the credit of transforming those vague ideas on the +immortality of the germ plasma which have been for some time in the +minds of many scientific men, myself among the number, into a clear +and sharply-defined theory, against the accuracy of which no doubt can +be raised either from the theoretical or from the empirical +standpoint. This theory, defined as it is by Weismann, has but +recently come before us, and some time must elapse before all the +consequences which it entails will be evident. But there is one +direction which I have for some time followed, and indeed began to +think out long before Weismann's remarkable work showed the importance +of this matter. I mean the origin of the conception of the immortal +soul. + +Before I approach the solution of this problem, it may be advisable to +recall in a few words to my readers the theory of the immortality of +the germ plasm. + +All unicellular beings, such as the protozoa and the simpler algae, +fungi, etc., reproduce themselves by means of simple fission. The +mother organism may split into two similar halves, as the amoeba does, +or, as is more common in the lowest unicellular plants, it may divide +into a great number of small spores. In these processes it often +happens that the whole body of the mother, the entire cell, may +resolve itself into two or more children; at times, however, a small +portion of the mother cell remains unused. This remnant, in the +spore-forming unicellular plants represented by the cell wall, is then +naturally dead. + +From this it follows that these unicellular beings are immortal. The +mother cell divides, the daughter cells resulting from the first +division repeat the process, the third generation does the same, and +so on. At each division the mother cell renews its youth and +multiplies, without ever dying. + +External circumstances can, of course, at any moment bring about the +death of these unicellular organisms, and in reality almost every +series of beings which originate from one another in this way is +interrupted by death. Some, however, persist. From the first +appearance of living organisms on our planet till to-day, several such +series--at the very least certainly one--have persisted. + +The immortality of unicellular beings is not at any time absolute, but +only potential. Weismann has recently directed attention to this +point. External occurrences may at any moment cause the death of an +individual, and in this way interrupt the immortal series; but in the +intimate organization of the living plasma there exist no seeds of +death. The plasma is itself immortal and will in fact live forever, +provided only external circumstances are favorable. + +Death is always said to be inherent in the nature of protoplasm. This +is not so. The plasm, as such, is immortal. + +But a further complication of great importance affects the +reproduction and the rejuvenescence of these unicellular organisms; +this is the process of conjugation. Two separate cells, distinct +individuals, fuse together. Their protoplasmic bodies not only unite +but intermingle, and their nuclei do likewise; from two individuals +one results. A single cell is thus produced, and this divides. As a +rule this cell seems stronger than the single individual before the +union. The offspring of a double individual, originated in this way, +increase for some time parthenogenetically by simple fission without +conjugation, until at length a second conjugation takes place among +them. I cannot consider further the origin of this universally +important process of conjugation. I will only suggest that a kind of +conjugation may have existed from the very beginning and may have been +determined by the original method of reproduction, if such existed. + +At any rate conjugation has been observed in very many plants and +animals, and is possibly universally present in the living world. + +Conjugation does not affect the theory of immortality. The double +individual produced from the fusion of two individuals, which divides +and lives on in its descendants, contains the substance of both. The +conjugating cells have in no way died during the process of +conjugation; they have only united. + +If we examine a little more closely the history of such a "family" of +unicellular beings from one period of conjugation to the next, we see +that a great number of single individuals, that is, single cells, have +proceeded from the double individual formed by conjugation. These may +all continue to increase by splitting in two, and then the family tree +is composed of dichotomously branching lines; or they may resolve +themselves into numerous spores, and then the family tree exhibits a +number of branches springing from the same point. + +The majority of these branches end blindly with the death, caused by +external circumstances, of that individual which corresponds with the +branch. Only a few persist till the next period of conjugation, and +then unite with other individuals and afford the opportunity for +giving rise to a new family tree. + +All the single individuals of such a genealogical table belong to one +another, even though they be isolated. Among certain infusoria and +other protista, they do, in fact, remain together and build up +branching colonies. At the end of each branch is situated an +infusorian (vorticella), and the whole colony represents in itself the +genealogical family tree. + +In the beginning, there existed no other animal organisms than these +aggregations of similar unicellular beings, all of which reproduced +themselves. Later on, division of labor made its appearance among the +individuals of the animal colony, and it increased their dependence +upon one another, so that their individuality was to a great extent +lost, and they were no longer able to live independently of one +another. + +By the development of this process, multicellular metazoa arose from +the colonies of similar protozoa, and at length culminated in the +higher animals and man. + +If we examine the human body, its origin and end, in the light of +these facts, we shall see that a comparison between the simple +immortal protozoa and man leads us to the result that man himself, or +at least a part of him and that the most important, is immortal. + +When we turn to the starting point of human development, we find an +egg cell and a spermatozoon, which unite and whose nuclei intermingle. +Thus a new cell is produced. This process is similar to the +conjugation of two unicellular beings, such as two acinetiform +infusoria, one of which, the female ([Symbol: Female]), is larger than +the other, the male ([Symbol: Male]). This difference of size in the +conjugating cell is, however, without importance. + +From this double cell produced by conjugation many generations of +cells arise by continual cell division in divergent series. Among the +infusoria these are all immortal, but many of them are destroyed, and +only a few persist till conjugation again takes place. The same is the +case with man. Numerous series of cell families arise, which are all +immortal: of these but few--strictly speaking, only one--live till the +next period of conjugation and then give the impulse which results in +the formation of a new diverging series of cells. The difference +between man and the infusorian is only that in the former the cells +which originate from the double cell (the fertilized ovum) remain +together and become differentiated one from another, while in the +latter the cells are usually scattered but remain alike in appearance, +etc. + +The seeds of death do not lie, as Weismann appears to assume, in the +differentiation of the cells of the higher animals. On the contrary, +all the cell series, not only those of the reproductive cells, are +immortal. As a matter of fact all must die; not because they +themselves contain the germs of death and have contained them from the +beginning, but because the structure which is built up by them +collectively finally brings about the death of all. The living plasm +in every cell is itself immortal. It is the higher life of the +collective organism which continually condemns countless cells to +death. They die, not because they cannot continue to exist as such but +because conditions necessary for their preservation are no longer +present. + +Thus, while the cells are themselves immortal, the whole organism +which they build up is mortal. The complex inter-dependence between +the single cells, which, since they have adapted themselves to +division of labor, has become necessary, carries with it, from the +beginning, the seeds of death. The mutual dependence ceases to work, +and the various cells are killed. + +The death of the individual is a consequence of the defective +precision in the working of the division of labor among the cells. +This defect, after a longer or shorter time, causes the death of all +the cells composing the body. Only those which quit the body retain +their power of living. + +Of all those countless cells which, in the course of a lifetime, are +thrown off from the body, only one kind is adapted for existence +outside the body, namely, the reproductive cells. + +Among the lower animals the reproductive cells often leave the body of +their parents only after the death of the latter. This is not the case +in man. + +All the cell series which do not take part in the formation of +reproductive cells, as well as all the reproductive cells without +exception, or with only a few exceptions, die through unfavorable +external conditions; just as all, or almost all, of the infusoria +which arose from the double cell die before they can conjugate again. + +At times, however, some of the infusoria persist till the next period +of conjugation, and in the same way, from time to time, some of the +human reproductive cells succeed in conjugating, and from them a new +individual arises. + +A man is the outgrowth of the double cell produced from the +conjugation of two human reproductive cells, and consists of all the +cells which arise from this and remain in connection with each other. +The human individual originates at the moment of the mingling of the +nuclei of the reproductive cells; and the details of this mingling +determine his individual peculiarities. + +The end of man is manifestly to preserve, to nourish, and to protect +the series of reproductive cells which are continually developing +within him, to select a suitable mate and to care for the children +which he produces. His whole structure is acquired by means of +selection with this one object in view, the maintenance of the series +of reproductive cells. + +From this standpoint the individual loses his significance and +becomes, so to speak, the slave of the reproductive cells. These are +the important and essential and also the undying parts of the +organism. Like raveled threads whose branches separate and reunite, +the series of reproductive cells permeate the successive generations +of the human race. They continually give off other cell series which +branch out from this network of reproductive cells, and, after a +longer or shorter course, come to an end. Twigs from these branches +represent the human individuals, and any one who considers the matter +must recognize that, as was said above, apart from the preservation of +the reproductive cell series the individuals are purposeless. + +It is on this basis that the moral ordering of the world must place +itself if it is to stand on any basis at all. It is an easy and a +pleasant task to interpret the facts of history from this standpoint. +Everything fits together and harmonizes, and each turn in the +historical development of civilization when observed from this point +of view acquires a simple and a clear causality. + +I cannot enlarge on this topic, engaging as it is, but here a further +question obtrudes itself. May there not be some connection between the +actual immortality of the germ cells, the continuity of their series +and the importance of the part they play, and the origin of the idea +of an immortal soul? May not the former have given rise to the latter? + +As a matter of fact, the series of reproductive cells possess the +essential attributes of the human soul; they are the immortal living +part of a man, which contain, in a latent form, his spiritual +peculiarities. The immortality of the reproductive cells is only +potential and is essentially different from that absolute eternal life +which certain religions ascribe to the soul. + +We must not, however, forget that at the time when the conception of a +soul arose among men, owing to a defective knowledge of the laws of +logic, no clear distinction was made between a potential immortality +and an absolute life without end. + +Herbert Spencer has pointed out that all religions have their origin +in reverence paid to ancestors. Each religion must have a true +foundation, and the deification of our forefathers has this true and +natural foundation inasmuch as they belong to the same series of +reproductive cells as their descendants. Of course our barbaric +ancestors who initiated the ancestor worship had no idea of this +motive for their religion, but that in no way disproves that this and +this alone was the _causa efficiens_ of the origin of such religions. +It is indeed typical of a religion that it depends upon facts which +are not discerned and which are not fully recognized. + +With the origin and development of every religion the origin and +development of the conception of the soul progresses step by step. + +We find the justification of ancestor worship in the immortality of +the reproductive cells, and in the continuity of their series. This +should also take a part in the origin of the conception of the soul. + +Spencer derives the conception of the existence of the soul from +dreams, and from the imagination of the mentally afflicted. The savage +dreams he is hunting, and wakes up to find himself at home. In his +dream he talks with friends who are not present where he sleeps; he +may even in the course of his dream encounter the dead. From this he +draws the conclusions--(1) that he himself has two persons, one +hunting while the other sleeps; (2) that his acquaintances also have a +double existence; and, from those cases in which he met with the dead, +(3) that they are not only double persons, but that one of the persons +is dead while the other continues to live. + +Thus, according to Spencer, the idea arises that man consists of two +separable thinking parts, and that one of these can survive the other. + +When a person faints and recovers, we say he comes to himself. That +is, a part of his person left him and has returned. But in this case, +as in the dream, the body has not divided, so that in a swoon the +outgoing portion is not corporeal. + +The savage will think that this is what remains alive after death, +for he is incapable of distinguishing between a swoon and death. Then +he will associate the part which leaves the body during a swoon with +that which gives life, and some will regard the heart, which fails to +beat after death, and others the breath, which ceases when life does, +as this life-giving part or soul. + +Thus far I am quoting from Spencer. + +The conception of the soul, which has thus arisen, has been utilized +by astute priests to obtain power over their fellow-men; while the +genuine founders of religions have made use of it, and by threats of +punishment, and promises of reward, have tried to induce mankind to +live uprightly. + +With this purpose in view, the teachers of religion have changed the +original conception of the soul and have added to it the attribute of +absolute immortality and eternal duration, an attribute which is in no +way connected by people in a low state of development with their +conception of the soul. + +At the present time among the religions of all civilized people the +undying soul plays an extraordinarily important part. + +I start from the position that no doctrine can receive a general +acceptation among men which does not depend on a truth of nature. The +various religions agree on one point, and this is the doctrine of the +immortal soul. Such a point of universal agreement, I am convinced, +cannot have been entirely derived from the air. It must have had some +foundation in fact, and the question arises, What was this foundation? +Dreams and phantasms, as Spencer believes? No; there must have been +something real and genuine, and the path we have entered upon to find +traces of this true foundation of the conception of the soul cannot be +distrusted. + +We must compare the conception of the soul as held by various related +religions, and strip off from it all those attributes which are not +common to all. But those which all the various religions agree in +ascribing to the soul we may regard as its true attributes. + +It would take too long to go into the details of this examination of +the conception of the soul. As the general result of a comparison of +the various views of the soul we may put down the following +characteristics which are invariably ascribed to it: + + (1) The soul is living. + + (2) It survives the body, and can continue to exist without + it. + + (3) During life it is contained in the body, but leaves it + after death. + + (4) The soul participates in the conduct of the body: after + the death of the latter, causality (retribution) can still + affect the soul. + +The characteristics (1) to (3) hold also for the series of +reproductive cells continually developing within the body; and these +attributes of the germ cells may well be the true but unrecognized +cause of the origin of those conceptions of the soul's character. + +This like holds true for (4), although the connection is not so +obvious. For this reason it will be advisable to consider the point in +more detail. + +It has been already indicated that the founders of religions have made +use of the survival of the soul after death to endeavor to lead +mankind to live righteously, by threats of punishments or promises of +reward, which will affect the soul after the death of the body. + +It is precisely on this point that in the most highly developed +religions there is the greatest falling off from the original +conception of the after-effect of human conduct on the soul, and the +most astounding things are inculcated by the Koran and other works +with respect to this. + +But here again we may separate the true kernel from the artificial +shell, and reach the conclusion that good conduct is advantageous for +the soul after the death of the body, and that bad conduct is +detrimental. In no other way can the Mohammedan paradise or the +Christian hell be explained than as sheer anthropomorphic realizations +of these facts, which can appeal even to the densest intellect. + +What then is good conduct, or bad? + +The question is easily asked, but without reference to external +circumstances impossible to answer. _Per se_ there is no good or bad +conduct. Under certain circumstances a vulgar, brutal murder may +become a glorious and heroic act, a good deed in the truest sense of +the word; as, for example, in the case of Charlotte Corday. Nor must +the view of one's fellow creatures be accepted as a criterion of good +or bad conduct, for different parties are apt to cherish diametrically +opposed opinions on one and the same subject. There remains then only +one's own inner feeling or conscience. Good conduct awakes in this a +feeling of pleasure, bad conduct a feeling of pain. And by this alone +can we discriminate. Now let us further ask. What sort of conduct +produces in our conscience pleasure and what sort of conduct induces +pain? If we investigate a great number of special cases, we shall +recognize that conduct which proves advantageous to the individual, to +the family, to the state, and finally to mankind, produces a good +conscience, and that conduct which is injurious to the same series +give rise to a bad conscience. If a collision of interests arise, it +is the degree of relationship which determines the influence of +conduct on the conscience. As, for instance, among the clans in +Scotland, a deed which is advantageous for the clan produces a good +conscience, even if it be injurious to the state and to mankind. + +The conscience is one of the mental faculties of man acquired by +selection and rendered possible by the construction and development of +the commonwealth of the state. Conscience urges us to live rightly, +that is, to do those things which will help ourselves and our family, +whereby our fellow creatures according to their degree of relationship +may be benefited. These are good deeds, and they will merit from the +teachers of religion much praise for the soul. We find, therefore, +that the only possible definition of a good deed is one which will +benefit the series of germ cells arising from one individual, and +further which will be of use to others with their own series of germ +cells, and that in proportion to the degree of connection +(relationship). + +It is clear that in this point also the ordinary conception of the +future fate of the soul agrees fundamentally with the result of +observation on the prosperity of the series of germ cells. + +As all the forces of nature, known to the ignorant barbarian only by +their visible workings, call forth in him certain vague and, +therefore, religious ideas, which are but a reflection of these forces +in an anthropomorphically distorted form, so the apparently +enigmatical conception of the eternal soul is founded on the actual +immortality and continuity of the germ plasma. + + * * * * * + + + + +COCOS PYNAERTI. + + +This is an acquisition to the dwarf growing palms, and a graceful +table plant. It first appeared in the nurseries of M. Pynaert, Ghent, +and is evidently a form of C. Weddelliana, having similar character, +though, as shown by the accompanying illustration, it is quite +distinct. The leaves are gracefully arched, the pinnules rather +broader than in the type, more closely arranged, and of a deep tone of +rich green. Such a small growing palm possessing elegant and distinct +character should become a favorite.--_The Gardener's Magazine_. + +[Illustration: COCOS PYNAERTI--A NEW PALM.] + + * * * * * + + + + +THE MISSISSIPPI RIVER.[1] + + [Footnote 1: Read May 17, 1890, before the Engineers' Club of + Philadelphia.] + +By JACQUES W. REDWAY. + + +INTRODUCTION. + +The purport of the following paper is to show that corrosion of its +banks and deposition of sediment constitute the legitimate business of +a river. If the bed of the Mississippi were of adamant, and its +drainage slopes were armored with chilled steel, its current would do +just what it has been doing in past ages--wear them away, and fill the +Gulf of Mexico with the detritus. + +Many thoughts were suggested by Mr. S.C. Clemens, erstwhile a +Mississippi pilot, and by Mr. D.A. Curtis. Both of these gentlemen +_know_ the river. + + +GENERAL GEOGRAPHY. + +The Mississippi River, as ordinarily regarded, has its head waters in +a chain of lakes situated mainly in Beltrami and Cass counties, +Minnesota. The lake most distant from the north is Elk Lake, so named +in the official surveys of the U.S. Land Office. A short stream flows +from Elk Lake to Lake Itaska, a beautiful sheet of water, considerably +larger than Elk Lake. From Lake Itaska it flows in a general +northeasterly direction, receiving the waters of innumerable springs +and ponds, among them Lake Bemidji, a body of water equal in size to +Lake Itaska. After a course of 135 miles the steam flows into Cass +Lake, absorbing in the meantime the waters of another chain of lakes, +discharged through Turtle River. From Cass Lake the waters flow a +distance of twenty miles, and are poured into Lake Winnibigoshish. The +latter has an area of eighty square miles; it is twice the size of +Cass Lake and more than six times that of Lake Itaska. From Lake +Winnibigoshish to the point where it receives the discharge of Leech +Lake, the river flows through an open savannah, from a quarter of a +mile to a mile in width. Forty miles beyond are Pokegama Falls. Here +the river flows from Pokegama Lake, falling about fourteen feet before +quiet water is reached. All the country about the headwaters is +densely wooded with Norway pine on the higher ground, and with birch, +maple, poplar and tamarack on the lower ground. Between Pokegama Falls +and the Falls of St. Anthony, the river receives the waters of a +number of other similar streams, all flowing from the lake region. + +At St. Paul the navigable stage of the river practically begins, +although there is more or less navigable water above the falls at +certain seasons. From St. Paul to Cairo the river flows between +bluffs, the terraces of Champlain times, from ten to fifty miles +apart. Between the bluffs are the bottom lands, often coincident with +the flood plain, along which the river channel wanders in a devious +course of 1,100 miles. The soil of the bottom lands is, of course, +alluvial, and was deposited by the river during past ages; that beyond +the bluffs is a part of the great intermontane plain, and is +sedentary--that is, it has not been materially disturbed since the +plain was raised above the sea level by the uplift of the continent. + +From Cairo, at the junction of the Ohio River, the plain to the +southward is nearly all made land, and in a few spots only does the +river touch soil which it has not itself made. Here the Lower +Mississippi proper begins, and here, at some not far distant time in +the past,[2] was the head of the Gulf of Mexico. A fuller description +of the Lower Mississippi is unnecessary here, inasmuch as the +following pages are mainly devoted to this part alone. + + [Footnote 2: Estimated at from 100,000 to 150,000 years. Such + estimates, however, are but little better than guesses.] + + +HISTORICAL. + +Nearly three and a half centuries have elapsed since De Soto, that +prince among explorers, traversed the broad prairies that lie between +the border highlands of the Western continent, and beheld the stream +which watered the future empire of the world. His chroniclers tell us +that he was raised to an upright position, so that he could catch a +fleeting glimpse of the restless, turbulent flood; for even then the +hand of death was upon him, and soon its waters were to enshroud his +mortal remains. "His soldiers," says Bancroft, "pronounced his eulogy +by grieving for their loss, and the priests chanted over his body the +first requiems ever heard on the Mississippi. To conceal his death, +his body was wrapped in a mantle, and, in the stillness of midnight, +was silently sunk in the middle of the stream." Just across the river +the Arkansas was pouring in its tumultuous flood, and its confluence +was the site of the future town of Napoleon, which in coming years was +to be historic ground. + +Worn by suffering, hardships and peril, and racked by the pestilential +fever that still hovers about the river lowlands, De Soto paid the +debt of nature, and his thrice decimated followers made their way back +to France. It seemed a strange, incredible story that they told, for +such a mighty river, with its vast plain, was beyond conception. Its +source, they said, was in the north--among the eternal snows--farther +than it had ever been given to man to penetrate. Its waters, they +thought, were poured into the Gulf of California, or perhaps into the +great Virginia Sea. Its flood, they said, was so great that if all the +rivers of Europe were gathered into one channel, they would not be a +tithe as large. But the people who heard these wonderful accounts were +unconcerned. The French monarch knew naught but to debauch his +heritance; the French courtier intrigued and plundered; the French +peasant, dogged and sullen in his long suffering, dragged out his +miserable existence. The flood of waters rolled on, and a hundred and +thirty years must come and go before the next white man should see the +sheen of its rippling. + +Let us cast a retrograde glance to the history of this period. It was +only fifty years before that Columbus had dropped anchor off the coral +reef of Samana Cay, and thrilled the Old World by announcing the +discovery of the New. Elizabeth, the virgin Queen of England, was a +proud, haughty girl just entering her teens, all unmindful of her +eventful future. Mary Queen of the Scots was a tiny infant in +swaddling clothes. The labors of Rafael Sanzio were still fresh in the +memory of his surviving pupils. Michael Angelo was in the zenith of +his fame, bending his energies to the beautifying of the great +cathedral. Martin Luther was in the sere old age of his life, waiting +for the command of the Master, which should bid him lay down his +armor. A hundred years were to elapse before Charles I. of England +must pay with his life the price of his folly. + +Joliet, a French trader, was a man possessed of far more brains than +marked the average men of his times. He had not only the indomitable +courage which is essential to the successful explorer, but he had also +the rare ability to manage men; and we find him in 1672 with a +commission from the French king directing him to explore the valley +which was to be a part of New France. The lands which he visited must +be his fee to the king; certain rights of trade he wisely secured to +himself. So, with Pere Marquette, a Jesuit priest, he undertook the +mission, which we may doubt whether to call a journey of discovery or +an errand of diplomacy. Crossing the ocean, their route lay along the +St. Lawrence River to the Great Lakes; through the Great Lakes to the +country of the Illini; down the Illinois to the Mississippi, and down +the Mississippi to its junction with the Arkansas. Here they encamped +near the site of Napoleon. Everywhere along their route they had won +the hearts of the savage Illini. They possessed that rare tact which +was born in French travelers, and which no English explorer ever had. +When they had reached the junction of the Arkansas, "they were kindly +received by the Indian tribes." They held a council with the various +chiefs, with whom they made a treaty. The treaty was celebrated by a +feast, and, if we may believe the record thereof, libations of wine +were freely poured forth to pledge the stipulations of the business +transaction. For a heavenly possession in the uncertain future, the +Indian acknowledged, by the cross raised in commemoration, that he had +bartered away his earthly kingdom. The title by which the Indian held +the soil wrested from the Mound-builder may not have been perfect; +that of the wily Joliet may have been equally defective. But Joliet +builded more wisely than he knew, for to this day, fraud, treachery +and broken faith are the chief witnesses to our treaties with the +aboriginal owners of the land. + +Nine years after the business venture of Joliet, La Salle received +letters extraordinary from the King of France, directing him to make +additional explorations along the course of the great river. He +organized an expedition, crossed the ocean, and made his way rapidly +to the scene of his explorations. Preparing his canoes and launches, +he followed the sinuous course of the river to Napoleon. His arrival +was celebrated by another feast and post-prandial business agreement, +and New France began its brief existence. Never in the history of the +world had such an empire been founded--such another could not be +formed until the domains of this had been widened from sea to sea, and +the energy of Saxon, Teuton and Kelt mingled to build a greater. + +To La Salle belongs the honor of tracing the true course of the +Mississippi river. He charted it with a faithfulness and accuracy that +would do credit to the surveys of the present day. He seemed to have +noted all the important feeders and tributaries, correctly locating +their points of confluence. He did not cease his work until he reached +the Gulf of Mexico.[3] So not only was La Salle the most indefatigable +explorer of this region, but he also earned the credit of having made +the most important discovery. + + [Footnote 3: From the best information I can gather I am unable to + decide to my own satisfaction whether or not La Salle discovered + the Red River. It is not improbable that he never saw this stream, + for it is more than likely that at that time, Red River poured its + waters directly into the Gulf of Mexico, through Atchafalaya and + Cocoudrie Bayous. That these were formerly a part of the channel + of Red River, there can be no doubt. The sluggish swale that now + leads from the river to the Gulf is a silted channel that was + formerly large enough to carry the whole volume of Red River. Such + changes in the channel of a river, when the latter flows through + "made" soil, are by no means infrequent. It is only a few years + since the Hoang River, "the sorrow of Han," broke through its + restraining banks, and poured its flood into the Gulf of + Pe-chee-lee, 350 miles distant from its former mouth.] + +With La Salle's exploration the future importance of the Mississippi +began; and though the railway has of late years largely supplanted it +as a commercial highway, yet, with the possible exception of the +Ganges, no other river in the world transports yearly a greater +tonnage of merchandise. The early traders were content to carry their +supplies back and forth in canoes. As settlement and business +increased, the canoe gave place to the raft, and the raft yielded to +the flatboat. In the course of time, steam was applied to the +propulsion of boats, and the flatboat yielded to the inevitable: the +palatial steamboat was supreme. But the days of the steamboat were +numbered when the civil war cast its blight over the land; and when +the years of strife were over, so also was the river traffic which had +created the floating palaces of the Mississippi. There were several +things that operated to prevent the reorganization of the fleet of +steamboats which for size, beauty and capacity were found in no other +part of the world. Many of these boats had been destroyed, and the +companies that owned them were financially ruined. Most of those +remaining were purchased or confiscated for military purposes, and +rebuilt either as transports or as gunboats. A period of unparalleled +railway construction began at the close of the war, and most of the +traffic was turned to the railway. Finally, it was discovered that a +puffy, wheezy tug, with its train of barges, costing but a few +thousand dollars, and equipped with half a score of men, could, at a +much less rate, tow a vastly greater cargo than the river steamer. +That discovery was the knell of the old-time steamboat, and the +beginning of a new era of navigation. Powerful as the railway may be, +we cannot shut our eyes to the fact that a tug and train of barges +will carry a cargo of merchandise from St. Paul to St. Louis for +one-tenth the sum the consignee must pay for railway transportation. +So, to-day, the river is just as important as a highway of commerce as +it was in the palmy days of the floating palace and river greyhound. +Railway traffic has enormously increased, but river traffic along the +most wonderful of streams has not materially lessened. + +The Mississippi is certainly a wonderful river. From Elk Lake to the +Gulf of Mexico it has a variable length of about 2,800 miles; from +Pass a l'Outre to the head of the Missouri its extent is nearly 4,200 +miles--a length not equaled by any other river in the world. It is +evident, by a moment of reflection, that a river which traverses a +great extent of latitude offers much greater facilities for commerce +and settlement than a longitudinal river. The Mississippi traverses a +greater breadth of latitude than any other river, except the Nile, for +its sources are in regions of almost arctic cold, while its delta is +in a land that is practically tropical. The volume of its flood is +surpassed by the Amazon and, perhaps, the Yukon. It discharges, +however, three times as much water as the Danube, twenty-five times as +much as the Rhine, and almost three hundred and fifty times as much as +the Thames. It has several hundred navigable tributaries, and its +navigable waters, stretched in a straight line, would reach nearly +three-fourths the distance around the earth. It is one of the most +sinuous of rivers. In one part of its course it flows in a channel +nearly 1,400 miles long to accomplish, as the crow flies, the distance +of 700 miles. In more than one place the current forms a loop ten, +twenty and even thirty miles around, rather than to cut through a neck +perhaps not half a mile in width. It is one of the most capricious of +rivers, for its channel rarely lies in the same place during two +successive seasons. The river manifests a strong inclination to move +east; and were La Salle to repeat his memorable voyage, he would touch +in scarcely half a score of places the course he formerly traveled; or +if he were to go over exactly the same course, he must of necessity +have his boats dragged over the ground, for almost the entire course +over which he traveled is now dry land. Since that time the river has +deserted almost all of its former channel, as if to repudiate its +connection with the after-dinner treaties of two hundred years lang +syne; in places its channel lies to the west, but for the greater +extent it is to the eastward.[4] + +[Footnote 4: "The bed of the river is so broad that the channel +meanders from side to side within the bed, just as the bed itself +meanders from bluff to bluff; and, as by erosions and deposits, the +river, in long periods of time, traverses the valley, so the channel +traverses the bed from bank to bank, justifying the remark often +heard, that 'not a square rod of the bed could be pointed out that had +not, at some time, been covered by the track of steamboats.'"--J.H. +SIMPSON, _Col. Eng., Brevet Brig.-Gen., U.S.A._] + + +PHYSICAL. + +The lower Mississippi is among the muddiest streams in the world. +During the average year it brings down 7,500,000,000 cubic yards of +sediment, discharging it along the lower course, or pushing it into +the Gulf. As one thinks of the small amount of sediment held in a +gallon or two of river water, a comprehension of this vast amount of +silt is impossible. It is enough to cover a square mile in area to a +depth of 268 feet. In five hundred years it would build above the sea +level a State as large and as high as Rhode Island. Thus, by means of +this sediment, the river has pushed its mouths fifty miles into the +sea, confining its flow within narrow strips of land--natural levees +made by the river itself. + +The Mississippi is notable for its varying length. Within the memory +of the oldest pilot the length of the river between St. Louis and New +Orleans has varied more than one hundred and fifty miles, being +sometimes longer and sometimes shorter, as the year may be one of +drought or of excessive rainfall. Occasionally the river will shorten +itself a score of miles at a single leap. The shortening invariably +takes place at one of its long sinuous curves for which it is so +remarkable. At a season when the volume of water begins to increase, +the narrow neck of the loop gives way little by little under the +continuous impact of the strengthening current. Narrower and narrower +it grows as the water ceaselessly cuts away the bank. Finally the +barrier is broken; there is a tumultuous meeting of waters; the next +steamboat that comes along goes through a new cut; and a moat or +ox-bow lake is the only reminder of the former channel.[5] + +[Footnote 5: One of the most noteworthy examples of these cut-offs is +Davis'. This cut-off occurred at Palmyra Bend, eighteen miles below +Vicksburg. The mid-channel distance around the bend was not far from +twenty miles; the neck was only twelve hundred feet across. The fall +of the river, measured around the bend, was about four inches per +mile; the slope, measured across the neck, was about five and one-half +feet, nearly twenty feet per mile. Inasmuch as the soil in the neck +was wholly alluvial, the current cut its new channel with exceedingly +great rapidity, soon clearing it out a mile in width and more than one +hundred feet in depth. The water rushed through the channel with such +a velocity that steamboats could not breast its flow for many weeks, +while the roaring of its flood could be heard many miles away. The +influence of the cut-off was felt both above and below Vicksburg for +several years after. The rate of erosion has been perceptibly +increased above Vicksburg: and it is not unlikely that the cut-off +which occurred a few years later at Commerce, about thirty miles below +Memphis, was a result of Davis' Cut. Other recent cut-offs have +occurred near Arkansas City, below Greenville, near Duncansby, below +Lake Providence at Vicksburg, and at Kienstra. The latter place is +below Natchez; all the others are between Natchez and Memphis. A +double cut-off is strongly threatened at Greenville.] + +In 1863 the city of Vicksburg was situated on the outer curve of such +a loop. At that time General Grant and his army were on the opposite +side of the river, and the whole power of the Federal government was +directed upon devising how the army might cross it and capture the +long-beleagured city. So an army engineer conceived the idea of +turning the river around the rear of the army. Accordingly, a canal +was cut across the loop, in order to make an artificial channel +through which its current might run. But the river steadfastly refused +to accept any channel it had not itself made, and the ditch soon +silted up. Twelve years or more afterward there was trouble; for the +river, which had all this time so persistently ignored the canal, one +stormy night, when its current was considerably swollen, took a notion +to adopt the canal that it had so long refused. Next morning the good +people of Vicksburg woke to find their metropolis, not on the river +channel, but practically an inland town overlooking a stagnant mud +flat. The town of Delta, which, the night before, was three miles +below Vicksburg, was, in the morning, two miles above it. Since that +time, energy and intelligence have conspired in its behalf, and +Vicksburg is still an important river port; but the channel of the +river is persistent, and constant effort and watchfulness alone keep a +depth of water sufficient for the needs of navigation before the +wharves. + +The average inhabitant of the flood plain of the Mississippi is not +surprised at this capriciousness of the river, for long experience has +taught him to look for it. During seasons of mean or of low water, +there is little or no trouble; but when floods begin to swell the +current, then it is high time to be on the alert, for no one knows +what a day or even an hour may bring forth. Perhaps a snag, loosened +from the bank above, may come floating down the stream. It strikes a +shallow place somewhere in the river, and thereupon anchors in +mid-channel. Directly it does, a small riffle or bar of silt will form +around it, and this, in turn, sends an eddying current over against +the bank. By and by the latter begins to be chipped away, little by +little. Perhaps the corrosion of the bank might not be noticed except +by a bottom land planter or a riverman. But there is no time to be +lost. If some unfortunate individual happens to possess belongings in +that vicinity, he simply lays aside his coat and works as if he were a +whole legion doing Caesar's bidding; he well knows that in a very few +hours the river will be swallowing up his real estate at the rate of +half an acre to the mouthful. It is certainly hard to see one's +earthly possessions disappear before the angry flood of the river, but +the bottom land planter does not complain, because the experience of +generations has taught him that he must expect it. A queer fortune +befell Island No. 74. + +Between the States of Arkansas and Mississippi there is a large +island, which, for want of a name, is commonly known as Island No. +74.[6] This slip of insular land is probably the only territory within +the United States and not of it, for this island is without the +boundaries of either State, county or township. It is not under +control of the government, because it is in the possession of an owner +whose claim is acknowledged by the government. The anomalous position +of the island as to political situation is due to the erosion of the +river as an active and the defects of statutory law as a passive +agent. According to the enactment whereby the States of Arkansas and +Mississippi were created, the river boundary of the former extends to +_mid-stream_; that of the latter to _mid-channel_. Herein is the +difficulty. A dissipated freshet turned the current against the +Mississippi bank, and shifted the former position of mid-channel many +rods to the eastward, so that the fortunate or unfortunate owner found +his possessions lying beyond both the mid-river point of Arkansas and +the mid-channel line of Mississippi. The owner of the plantation may +be unhappy at time of election, for he is practically a non-resident +of any political division. His grief, however, is somewhat assuaged +when the tax gatherer calls, for, being outside of all political +boundaries, he has no taxes to pay. + +[Footnote 6: For convenience to navigation, the islands in the lower +Mississippi, beginning at St. Louis, are numbered. Many of them, +however, have local names by which they are frequently known.] + +Within a few years the town of Napoleon, which has already been +mentioned as the site which beheld the cross erected by Marquette and +the seizure of La Salle, was the scene of still another chapter in +history. Almost two hundred years from the time when Joliet and +Marquette beheld the historic ground, the river turned its current +against the banks, and in a few hours the crumbling walls of an old +stone building, half a mile or more from the river banks, were the +surviving monument that marked the former location of the town. + +The Mississippi is indeed a grand study, and the people who have lived +in its valley during past ages have seen the river doing just what it +is doing to-day; and as race has succeeded race, each in turn has seen +the landmarks of its predecessors swept away by its angry flood and +buried beneath its sediment. Ever since the crests of the Appalachian +and Rocky Mountains were thrust up above the sea, the river has been +wearing them away, and bearing the scourings to the vast plain below. +In the time of its building it has made the greatest and the richest +valley on the face of the earth; next to that of the Amazon it is the +largest, covering an area of one and one-quarter million square miles. +The river and its tributaries drain twenty-eight States and +Territories--an area equal to that of all Europe except Russia. This +basin includes half the area of the United States, exclusive of +Alaska. It is five times as large as Austria-Hungary, six times the +size of France or Germany, nine times the area of Spain, and ten times +that of the British Isles. Measured by its grain-producing capacity, +this valley is capable of supporting a larger population than any +other physical region on the face of the earth. Already it is the +foremost region in the world in the production of grain, meat and +cotton. The rich soil, sedentary on the prairie and alluvial in the +bottomlands, is almost inexhaustible in its nutritious qualities. The +soil cannot be "worn out" in the bottomlands, for nature restores its +vitality by bringing fresh supplies from the highlands as fast or +faster than the seed crop exhausts it. Sixty bushels of wheat or two +bales of cotton may be harvested from an acre of bottom lands. So vast +in proportions is the yearly crop of food stuffs that more than three +hundred thousand freight cars and about two thousand vessels are +required to move the crop from farm to market. One hundred and +twenty-five thousand miles of railway, fifteen thousand miles of +navigable water, exclusive of the Great Lakes, and several thousand +miles of canals are insufficient to transport this enormous +production; thousands of miles of railway are therefore yearly built +in order to keep pace with the growth of population and the settlement +of new lands. To the natural resources of the soil add the enormous +mineral wealth hidden but a few feet below the surface, and wonder +grows to amazement. Coal fields surpassing in extent all the remaining +fields in the world; iron ore sufficient to stock the world with iron +and steel for the next thousand years; copper of the finest quality; +zinc, lead, salt, building stone and timber, all in quantities +sufficient for a population a hundred times as great. Is it strange +that wise economists point to this territory and say, "Behold the +future empire of the world"? Where in the wide world is another valley +in which climate, latitude and nature have been so liberal? + +It is only a few years since the Indian and the bison divided between +them the sole possession of this region. What a change hath the hand +of destiny wrought! What a revelation, had some unseen hand lifted the +curtain that separated the past from the future! Iron, steam and +electricity have in them more of mysterious power than ever oriental +fancy accredited to the genii of the lamp, and the future of the basin +of the Mississippi will be a greater wonder than the past. + +The feast of La Salle was the death warrant of the Indian, and the +Aryan has crowded out the Indian, just as the latter evicted the mound +builder--just as the mound builder overcame the people whose monuments +of burned brick and cut stone now lie fifty feet below the surface. +Only a few centuries have gone by since these happenings; can we +number the years hence when rapacious hordes from another land shall +drive out the effete descendants of the now sturdy Aryan? + +(_To be continued_.) + + * * * * * + + + + +FREEZING MIXTURES. + + +The following selection of mixtures causing various degrees of cold, +the starting point of the cooling being indicated in the first column, +will probably serve many purposes. It should be stated that the amount +of depression in temperature will practically be the same, even if the +temperature to start from is higher. Of course in the case of snow it +cannot be higher than 0 deg. C. (32 deg. F.) But in some cases it is necessary +to start at a temperature below 0 deg. C. For instance, the temperature of +-49 deg. C. may be reached by mixing 1 part of snow with 1/2 part of dilute +nitric acid. But then the snow must have the temperature -23 deg. C. If it +were only at 0 deg. C., the depression would be only to about -26 deg. C.: + + _________________________________________________________________ + | + | The temperature sinks + Substances to be mixed in parts by |------------------------- + weight. | from | to + _______________________________________|____________|____________ + | | + 1. Water. 1 | +10 deg. C. | -15.5 deg. C. + Ammonium nitrate. 1 | | + 2. Dil. hydrochloric acid. 10 | +10 | -17.8 + Sodium sulphate. 16 | | + 3. Dil. hydrochloric acid. 1 | +10 | -16 + Sodium sulphate. 11/2 | | + 4. Snow. 1 | + 0 | -32.5 + Sulphuric acid. 4 | | + Water. 1 | | + 5. Snow. 1 | - 7 | -51 + Dil. sulphuric acid. 1 | | + 6. Snow. 1 | -23 | -49 + Dil. nitric acid. 1/2 | | + 7. Snow. 1 | 0 | -17.8 + Sodium chloride. 1 | | + 8. Snow. 1 | 0 | -49 + Calcium chloride. 1.3 | | + 9. Snow. 1 | 0 | -33 + Hydrochloric acid. 0.625 | | + 10. Snow. 1 | 0 | -24 + Sodium chloride. 0.4 | | + Ammon. chloride. 0.2 | | + 11. Snow. 1 | 0 | -31 + Sodium chloride. 0.416 | | + Ammon. nitrate. 0.416 | | + _______________________________________|____________|____________ + + * * * * * + + + + +THE APPLICATION OF ELECTROLYSIS TO QUALITATIVE ANALYSIS. + +By CHARLES A. KOHN, B.Sc., Ph.D., Assistant Lecturer in Chemistry, +University College, Liverpool. + + +The first application of electrolysis to chemical analysis was made by +Gaultier de Claubry, in 1850, who employed the electric current for +the detection of metals when in solution. Other early workers followed +in this direction, and in 1861 Bloxam published two papers (J. Chem. +Soc., 13, 12 and 338) on "The application of electrolysis to the +detection of poisonous metals in mixtures containing organic matters." +In these papers a description is given of means for detecting small +quantities of arsenic and of antimony by subjecting their acidulated +solutions to electrolysis. The arsenic was evolved as hydride and +recognized by the usual reactions, while the antimony was mainly +deposited as metal upon the cathode. The electrolytic method for the +detection of arsenic, in which all fear of contamination from impure +zinc is overcome, has since been elaborated by Wolff, who has +succeeded in detecting as little as 0.00001 grm. arsenious oxide by +this means (this Journal, 1887, 147). + +In a somewhat different manner the voltaic current is made use of in +ordinary qualitative analysis for the detection of tin, antimony, +silver, lead, arsenic, etc., by employing a more electro-positive +metal to precipitate a less electro-positive one from its solution. + +The quantitative electrolytic methods of analysis, some of which I had +the honor of bringing before the notice of the Society some time back +(this Journal, 1889, 256), have placed a number of methods of +determination and separation of metals in the hands of chemists, which +can be employed with advantage in qualitative analysis, especially in +case of medical and medico-legal inquiry. These methods are not +supposed to supersede in any way the ordinary methods of qualitative +analysis, but to serve as a final and crucial means of identification, +and thus to render it possible to detect very small quantities of the +substances in question with very great certainty. As such they fulfill +the required conditions admirably, being readily carried out, +comparatively free from contamination with impure reagents, and +capable of being rendered quantitative whenever desired. + +In conjunction with Mr. E.V. Ellis, B.Sc., I have examined the +applicability of the electrolytic methods for the detection of the +chief mineral poisons (with the exception of arsenic, an electrolytic +process for the detection of which has already been devised, as +described), viz., antimony, mercury, lead, and copper. + +_Antimony_.--The method employed in the case of antimony is that +adopted in its quantitative estimation by means of electrolysis, a +method which insures a complete separation from those metals with +which it is precipitated in the ordinary course of analysis--arsenic +and tin. This fact is of considerable importance in reference to the +special objects for which these methods have been worked out. + +The precipitated sulphide is dissolved in potassium sulphide, and the +resultant solution, after warming with a little hydrogen peroxide to +discolorize any poly-sulphides that may be present, electrolyzed with +a current of 1.5-2 c.c. of electrolytic gas per minute (10.436 c.c. at +0 deg. and 760 mm. = 1 ampere), when the antimony is deposited as metal +upon the negative electrode. One part of antimony (as metal) in +1,500,000 parts of solution may be thus detected, a reaction thirty +times more delicate than the deposition by means of zinc and +potassium. The stain on the cathode, which latter is best used in the +form of a piece of platinum foil about 1 sq. cm. in diameter, is +distinct even with a solution containing 1/28 mgrm. of antimony; and +by carefully evaporating a little ammonium sulphide on the foil, or +by dissolving the stain in hot hydrochloric acid and then passing a +few bubbles of sulphureted hydrogen gas into the solution, the orange +colored sulphide is obtained as a satisfactory confirmatory test. The +detection of 0.0001 grm. of metal can be fully relied on under all +conditions, and one hour is sufficient to completely precipitate such +small quantities. + +_Mercury_.--Mercury is best separated from its nitric acid solution on +a small closely wound spiral of platinum wire. The solution to be +tested is acidified with nitric acid and electrolyzed with a current +of 4-5 c.c. (c.c. refer to c.c. of electrolytic gas per minute). The +deposition is effected in half an hour. The deposited metal is removed +from the spiral by heating the latter gently in a test tube, when the +mercury forms in characteristic globules on the upper portion of the +tube. As a confirmatory and very characteristic test, a crystal of +iodine is dropped into the tube, and the whole allowed to stand for a +short time, when the presence of mercury is indicated by the formation +of the red iodide. 0.0001 grm. of mercury in 150 c.c. of solution can +be clearly detected. + +Wolff has applied this test under similar conditions, using a special +form of apparatus and a silver-coated iron anode (this Journal, 1888, +454). + +_Lead_.--Lead is precipitated either as PbO_{2} at the anode from a +nitric acid solution or as metal at the cathode from an ammonium +oxalate solution. In both cases a current of 2-3 c.c. suffices to +effect the deposition in one hour. + +Here, again, 0.0001 grm. of metal in 150 c.c. of solution can be +easily detected. With both solutions this amount gives a distinct +discoloration to the platinum spiral, on which the deposition is best +effected. As a confirmatory test the deposited metal is dissolved in +nitric acid and tested with sulphureted hydrogen, or the spiral may be +placed in a test tube and warmed with a crystal of iodine, when the +yellow iodide is formed. This latter reaction is very distinct, +especially in the case of the peroxide. + +Of the above two methods, that in which an ammonium oxalate solution +is used is the more delicate, although it cannot be employed +quantitatively, owing to the oxidation of the metal that takes place. + +An addition of 1 grm. of ammonium oxalate to the suspected solution is +sufficient. + +_Copper_.--0.00005 grm. of copper can be very readily detected by +electrolyzing an acid solution in the usual way. A spiral of platinum +wire is employed as the cathode, and the presence of the metal +confirmed for by dissolving it in a little nitric acid, diluting with +water and adding potassium ferrocyanide. + +To detect these metals in cases of poisoning, the organic matter with +which they are associated must first be destroyed in the usual way by +means of hydrochloric acid and potassium chlorate, and the +precipitates obtained in the ordinary course of analysis, then +subjected, at suitable stages, to electrolysis. As the solutions thus +obtained will be still contaminated by some organic matter, it is +necessary to pass the current for a longer time than indicated above. +On the other hand, _urine_ can be tested directly for these poisons. + +The presence of mercury or of copper may be detected by acidifying the +urine with 2-3 c.c. of nitric acid (conc.), and electrolyzing as +described. 0.0001 grm. of metal in 30 c.c. of urine can be detected +thus, or 1 part in 300,000 of urine. + +Lead does not separate well as peroxide from urine, but if ammonium +oxalate be added, and the lead deposited as metal, the reaction is +quite as delicate as in aqueous solution, and 0.0001 grm. of lead can +be thus detected. + +With antimony it is advisable to precipitate it first as sulphide, but +it can be detected directly, though not so satisfactorily, by +acidifying the urine with 2-3 c.c. of sulphuric acid (dil.), and +electrolyzing with a current of 1-5 to 2 c.c. In this case also it is +precipitated as metal upon the cathode (cp. Chittenden, Proceedings +Connecticut Acad. Science, Vol. 8). + +In the presence of urine it is advisable to continue the passage of +the current for about twice the time required in the case of aqueous +solutions. + +That an approximately quantitative result can be obtained under the +above conditions was shown in several cases in which deposition of +0.001 grm. of metal was confirmed with considerable accuracy, the +spiral or foil being weighed before and after the experiment. + +A comparison of the delicacy of these tests with the ordinary +qualitative tests for antimony, mercury, lead, and copper by means of +sulphureted hydrogen, showed that the two were equally delicate in the +case of antimony and of copper, but that in that of mercury and of +lead the electrolytic test was at least eight times the more delicate. +These comparisons were made in aqueous solutions. In testing urine the +value of the electrolytic method is still more evident, for here the +color of the liquid interferes materially with the reliability of the +ordinary qualitative tests when only very small quantities of the +metals referred to are present. + +Beyond the detection of mineral poisons, qualitative electrolysis can +only offer attraction to analysts in special cases, and the data on +the subject are to be found in the many electrolytic methods already +published. Beyond testing for gold and silver in this manner, I have +not therefore examined the applicability of these methods further. + +The detection of small quantities of gold and silver is of +considerable importance, and advantage can be taken of the ease with +which they are separated from potassium cyanide solution by the +electric current for this purpose. + +_Silver_.--Silver is obtained as chloride in the course of analysis. +To confirm for the metal electrolytically, this precipitate is +dissolved in potassium cyanide and the resulting solution electrolyzed +with a current of 1-1.5 c.c. A spiral of platinum wire is employed as +the anode, from which the silver may be dissolved by means of nitric +acid, and tested for by hydrochloric acid or by sulphureted hydrogen. +0.0001 grm. of silver in 150 c.c. of solution can be detected thus, +and one hour is sufficient for the deposition. + +_Gold_.--Gold is deposited under similar conditions to silver from +cyanide solutions. The deposit, which is rather dark colored, can be +dissolved in aqua regia and confirmed for by the Cassius' purple test. +Here again 0.0001 grm. of metal in 150 c.c. of solution can be +detected without any difficulty. + +As gold and silver are both extracted from quartziferous ores by +treatment with potassium cyanide solution according to the +MacArthur-Forrest process of gold extraction (this Journal, 1890, +267), this electrolytic method should prove very useful. By +electrolyzing the resulting solution a mixture of gold and silver will +be deposited upon the cathode, which can then be parted by nitric acid +and tested for as described. + + +DISCUSSION. + +The chairman said that there was little doubt but that further +investigation into electrolytic methods of chemical analysis would +give even more valuable results than those already obtained. +Systematic investigations of the subject, such as have been given by +Dr. Kohn, would go far to prove the adaptability of this method as a +substitute for or aid in ordinary qualitative examinations. The +remarks of Dr. Kohn respecting quantitative examinations were very +interesting, and well worth following up by other practical work. + +Professor Campbell Brown said that Dr. Kohn had shown that electricity +brought the same kind of elegance, neatness, and simplicity into +analysis that it did into lighting and silver plating. + +In its applications to the detection of poisons, he understood Dr. +Kohn to say that the poisons must first be extracted by chemical +means. That would not be sufficient, and he had no doubt that if the +subject was pursued farther they would have a paper from him (Dr. +Kohn) some day, indicating that he had obtained arsenic and such +poisons without the previous separation of the metal from organic +matter. It was a very great desideratum to have a method for detecting +arsenic and separating it from the contents of the stomach and food +directly without previous destruction of the organic matter, and he +hoped Dr. Kohn would pursue his work in that direction. + +Dr. Hurter said he was about to construct a new laboratory, and he +would assure them that one of its arrangements would be the +installation of electricity, by which to carry out researches similar +to those described. He was very glad to learn that the presence of +arsenic, etc., could be readily proved by means of electrolysis. + + * * * * * + + +A NEW CATALOGUE OF VALUABLE PAPERS + + +Contained in SCIENTIFIC AMERICAN SUPPLEMENT during the past ten years, +sent _free of charge_ to any address. MUNN & CO., 361 Broadway, New +York. + + * * * * * + + +THE SCIENTIFIC AMERICAN + +ARCHITECTS AND BUILDERS EDITION. + +$2.50 A YEAR. 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