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results of some experiments which may seem more significant to the writer than they would to a physicist. Up to the time Bigelow and Hunter's paper was published, at least, the literature did not seem to cover the point at all satisfactorily, yet many statements and implications seem to be clear. Ramsay and Shield's classic determinations of surface tension based upon capillary rise may be cited as an example. If capillary rise is affected by the nature of the tube, their results would apparently be invalidated.

Do not three substances ordinarily play parts in capillarity, and does not the result depend on the identity of each of the substances? If water, air and glass are the substances, the water heaps up against the glass, and if the tube is of hair-like diameter there is a rise of water. Is not this due to the fact

that where water, air and glass come together molecules of water are drawn toward the glass

much more than toward molecules of air or other molecules of water?

The mechanics of this process seem simple, whereas it is difficult to conceive how the raising of the liquid can be a product of its surface tension alone, even though the walls of the tube above the liquid have a contractile coating of adsorbed liquid or a membranous extension of the liquid in the tube.

The writer is particularly interested in the part that capillarity or differences in intermolecular attractions may play in oil and gas accumulation. In the vicinity of oil and gas pools which occupy the pores of rocks in the earth, water with various quantities of salt in solution, oil of one or more kinds, natural gas and perhaps air are in contact with each other and with various minerals. Oil and gas are found in relatively large-pored rocks, in pools which show some similarity in shape and the pressure upon them is usually several hundred pounds to the square inch. The pressure on some pools is greater than that which would be exerted by a column of water extending to the surface. May not these features be ex

Washburne, C. W., "The Capillary Concentration of Gas and Oil,'' Am. Inst. Min. Eng. Trans., Vol. 50, p. 830, 1915.

plained in considerable part by differences in intermolecular attractions?

E. W. SHAW5

SYNCHRONOUS RHYTHMIC MOVEMENTS OF FALL WEB-WORM LARVÆ

RECENT discussion in SCIENCE of synchronous actions of certain animals, notably, flashing of fireflies, brings to mind a habit of the larvæ of the fall web-worm (Hyphantria cunea), which seems to be of the same nature. Whether it has been noted in the literature or not I am unable to say; probably it has, as it is of common occurrence. In any event a short account of the habit may not be out of place in this connection.

Fall web-worm larvæ, scattered over the outside of the web, may be seen, at intervals of from three to five minutes, to start a sharp rhythmic swaying from side to side, accomplished by raising the anterior half of the body to a semi-erect position, then moving it quickly, first to one side then to the other, through an angle of about ninety degrees. The movement is started by a few of the larvæ, but in a few seconds all the individuals in the colony will be moving in the same manner and in perfect unison. I do not have my notes at hand but, as I remember it, the movements were at the rate of about forty per minute and continued each time for from forty-five seconds to more than a minute. Even more suddenly than they start, the movements

cease.

What the cause is for this strange habit is a puzzle. It seems to have nothing to do with spinning the web. Artificial stimuli failed to start them before the end of the resting interval although various means were tried. These included sounds, both musical and otherwise, made with various instruments, smoke and strong chemical odors, jarring and several other devices which suggested themselves at the time. Equally futile were attempts to stop the movements.

There seemed to be no leader, the swaying starting one time in one part of the colony or even in several parts at once, and again in

5 Published by permission of the director, U. S. Geological Survey.

some other part. Invariably, however, all would join in.

This habit was first observed by me several years ago, just how long I do not remember. It is associated with my earliest recollections of the insect. I have made more or less careful observation of it and taken notes several times, the first time in 1912. I do not think that I ever saw a colony that did not have the habit and I have had them in the laboratory every summer for several years. Observations of the habit may be made on colonies confined in the breeding cage or on those in the natural conditions. There seems to be no difference.

There is no doubt in my mind that this habit is an excellent example of synchronous rhythmic motion, not occasional or accidental, but habitual with the species. It may be well added to Mr. Craig's single, more or less doubtful, example, that of the chirping of crickets. L. M. PEAIRS

ENTOMOLOGICAL LABORATORY,
WEST VIRGINIA UNIVERSITY

THE POPULAR NAMES OF NORTH AMERICAN PLANTS

AN article under this title in SCIENCE for February 2, by J. Adams, opens a question which has interested the present writer partly for the same reasons as there given, and he has passed through various stages of mental attitude toward it.

A notable fact is that common names when once established are apparently more stable than the scientific names. The names of birds furnish a good example of this, very few common names having been changed in the last fifteen years while a fourth or more of the scientific names have been changed, and some of them two or three times. However, the number of species of seed plants is about ten times as great as that of birds.

This very stability indicates difficulty in establishing common names where none exist. Names are a result of necessary "handles," and the greater part of those species which have not received them are not regarded frequently enough to establish names. The essential qualities of a name would seem to be sig

nificance and simplicity. The use of qualifying adjectives should be avoided as far as possible. The writer is not certain that a species must bear the same name in different regions, or that different species may not have the same one inasmuch as a name which is appropriate in one place may not be in another, and similar species often occupy similar places in different regions. The writer places much value on local lists, keys, etc., including a single state or natural area. This restricts the number of species involved and simplifies identification.

The surest way to acquaint the general public with the names of plants is through illustrations. Is it not possible to have a cooperative system by which different states would be responsible for certain portions and thus distribute the cost of production as widely as possible? This would eliminate the duplication now current from the publication of similar material in different places and permit the use of first-class illustrations of uniform quality, as well as help to unify the names. O. A. STEVENS AGRICULTURAL COLLEGE, N. D.

FAUNAL CONDITIONS IN SOUTH GEORGIA ISLANDS

DURING a recent visit to the islands of South Georgia (latitude 54° south) a very curious faunal condition was noted, and as this is, perhaps, of biological interest, it may be well to state briefly the facts of the case.

South Georgia lies in the sub-Antarctic region a few hundred miles to the east of Cape Horn. The season is open for about three months, but quite rigorous the remainder of the year. The principal vegetation is tussock grass, and this at one time supported many rabbits and perhaps a few other species of mammals. A few decades ago, the whaling industry was started with South Georgia as a base of operations. To-day there are nine whaling stations on the large island, and in a good season of three or four months, several thousand whales are handled. The carcasses are allowed to drift along the beach, as soon as the outer coating of blubber has been removed.

As a result of this, there are several miles of these huge decaying masses around the various stations.

Until about thirty years ago, there were no rats on the islands. At that time a sealing vessel allowed a few rats to go ashore, and the result to-day is appalling in its enormity.

The conditions have been ideal for these rats-with their nests in the tangled bunches of tussock and peat, and with a constant supply of meat in all stages of decomposition and cold storage close at hand!

There are literally millions of these rodents working away at the carcasses and swarming along the well-traveled trail which they have made on the mountain slopes. Even when the winter snows cover the place, operations in this rat haven are not stopped.

It was stated at one of the whaling stations that the rats have devastated the few small animals living on the island, and, indeed, are a menace to the health and safety of the place.

It would be interesting to know what characteristics the rat would develop after a few years of such a specialized habitat.

I. A. LUKE

SCIENTIFIC BOOKS

Les Sciences Biologiques Appliquées à l'Agriculture et la Lutte Contre les Ennemis des Plantes aux États-Unis. By DR. PAUL MARCHAL. Extrait des Annales des Épiphyties Tome Troisième. Paris, Librairie Lhomme. 1916. Pp. 30-390.

It does not seem like four years since Dr. Marchal visited this country and traveled from east to west and north to south, visiting the field laboratories of the Bureau of Entomology and educational institutions, yet actually that trip was taken in the summer of 1913. His book, under the title (translated) "Biological Sciences Applied to Agriculture and the Struggle against the Enemies of Plants in the United States," was received in this country in November last, its publication having been delayed by the war, and it is even now printed only in a very small edition. It is a large royal octavo volume covering nearly four hundred pages, abundantly illustrated.

Marchal has a remarkable mind. It is little less than marvelous that in two months and a half he should have grasped the whole field in so perfect a way as to be able to write a book which is especially illuminating to us who are in the middle of things and who can not get the perspective which he reached after he returned to France and collected and classified his notes and impressions. The larger part of the book is devoted to the Bureau of Entomology, pages 52 to 198 being given to this service. The rest of the Department of Agriculture is considered in the following 30 pages, and 20 more are given to the experiment stations, the state entomologists, the Horticultural Commission of California, and the forestry services of the different states. Then follow 40 pages on universities and agricultural colleges, especial space being given to Cornell University and the universities of Illinois, California, Stanford and Harvard. He is enthusiastic over the Association of Economic Entomologists. The remaining 100 pages of the book are devoted to chapters on insect carriers of disease, the methods employed in the struggle against the enemies of crops (this chapter being divided into cultural methods, biological methods and technical methods), the laws concerning the protection of plants, including the insecticide law, and a conclusion. In this conclusion, after praising in an unstinted way the establishments of this country and the work which has been done, he especially points out that, far from narrowing itself in applications of science, the United States holds a place of the first rank in creative science. He thinks that France has much to learn from America, although it would be a mistake in his country to create an organization imitating in all respects the Department of Agriculture at Washington. He shows that the economic and cultural conditions are quite different on the two continents and that certain questions which have prime importance here have only a secondary interest in France. He is inclined to think that the United States Department of Agriculture is rather over organized, and thinks that the future will bring about a

simplification of its constituent elements. The main lesson that he learned by his journey is that France can no longer remain stationary in these matters and that it should make efforts to organize biology as applied to agriculture upon a large and solid basis, and he proceeds with practical suggestions in this direction. He praises the Federal Horticultural Board, the Federal Insecticide Board, and the Horticultural Commission of California, and thinks that all of these should be imitated in France. He especially points out the necessity for the introduction into France of such education as our young men get in applied biology in the agricultural colleges and universities like Cornell and Illinois. There is, he points out, in France at the present time no way of getting a scientific education in biological studies as applied to agriculture.

After pointing out some of the great examples of monetary saving in this country as the result of work in applied biology, he closes with the sentence, "These are great examples which it is well to recall, for they establish with the most complete evidence the fact that there is no other sure way than that of scientific organization of work to get full value from the national soil and to give back to agriculture the greatest possible part of the riches which are lost to it annually from pests."

L. O. HOWARD

CONCERNING THE HISTORY OF
FINGER-PRINTS

SIR WILLIAM J. HERSCHEL published recently a brief pamphlet of 41 pages under the title "The Origin of Finger-Printing" (Oxford University Press, 1916). This is mainly an autobiographical sketch, giving in detail the story of how the author during the time of his useful service in India (1853-78) conceived the notion of finger-prints and elaborated this system, which was subsequently developed and placed on a truly scientific basis by Sir Francis Galton. We are indebted to Sir W. Herschel for his interesting document: it is always valuable when one who has played

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a prominent rôle in inaugurating a new movement presents us with a record of what he believes was his share in bringing about this innovation or invention. The inventor, however, will seldom be able to write impartially the history of his own invention; no one, in fact, whether statesman, artist, poet or scholar, while recording his own history, has the faculty (I should even say, the right) of clearly determining his own place in the long chain of historical development. This judgment must be left to the historian of the future. The principal purpose by which Sir W. Herschel was guided in writing his account is to demonstrate that he was the real "discoverer of finger-prints in Bengal in 1858, entirely from his own resources, and to discredit all other claims to priority in this matter, especially those on the part of the Chinese. I regret that the author has failed to take notice of the "History of the Finger-Print System published by me in the Smithsonian Report for 1912 (pp. 631-652, Washington, 1913). Not only are Sir W. Herschel's great merits and his share in the history of the invention, if invention it may be called, duly acknowledged and objectively expounded there, but he would also have found there all the available evidence in favor of the Chinese, Japanese and Tibetans, all of whom applied ages ago with full consciousness the system of finger-prints for the purpose of identifying individuals. The few modern traces of evidence known to Sir W. Herschel are treated by him slightly, and he wonders that " a system so practically useful as this could have been known in the great lands of the East for generations past, without arresting the notice of western statesmen, merchants, travelers and students." The Mohammedan authors who visited China did not fail to describe this system. Rashid-eddin, the famous Persian historian, who wrote in 1303, reports as follows:

When matters have passed the six boards of the Chinese, they are remitted to the Council of State, where they are discussed, and the decision is issued after being verified by the khat angusht or "fingersignature" of all who have a right to a voice in

the council. This "finger-signature'' indicates that the act, to which it is attached in attestation, has been discussed and definitively approved by those whose mark has thus been put upon it. It is usual in Cathay [China], when any contract is entered into, for the outline of the fingers of the parties to be traced upon the document. For experience shows that no two individuals have fingers precisely alike. The hand of the contracting party is set upon the back of the paper containing the deed, and lines are then traced round his fingers up to the knuckles, in order that if ever one of them should deny his obligation this tracing may be compared with his fingers and he may thus be convicted.1

Professor Henri Cordier of Paris, the editor of Yule's famous work, adds to this passage a footnote relative to the history of fingerprints, and commenting on the claim of Sir W. Herschel, tersely remarks:

Sir W. Herschel was entirely wrong; Mr. Faulds protested against the claim of Sir W. Herschel, and finally a Japanese gentlemen, Kumagusu Minakata, proved the case for the Japanese and the Chinese. None of these writers quoted the passage of Rashideddin which is a peremptory proof of the antiquity of the use of finger-prints by the Chinese.

Indeed it is, and the observation that no two individuals have finger-marks precisely alike is thoroughly Galtonian. There is the earlier testimony of the Arabic merchant Soleiman, who wrote in A.D. 851, and who states that in China creditor's bills were marked by the debtor with his middle finger and index united (see my History, p. 643). But we have more. E. Chavannes, in reviewing my article in the Toung Pao (1913, p. 490), has pointed out three contracts of the T'ang period, dated A.D. 782 and 786 and discovered in Turkestan (two by Sir Aurel Stein), which were provided with the finger-marks of both parties, and contain at the end the typical formula:

The two parties have found this just and clear, and have affixed the impressions of their fingers as a distinctive mark.2

A clay seal for which no later date than the 1 See H. Yule, "Cathay," new ed., Vol. III., p. 123, London, 1914, Hakluyt Society.

2 See A. Stein, "Ancient Khotan," Vol. I., pp. 525-529, Oxford, 1907, where the three documents are published and translated by Chavannes.

third century B.C. can be assumed, and which bears on its reverse a very deeply and clearly cut impression of the owner's thumb-mark, has been brought back by me from China, and is illustrated and described in the above paper. I have also shown how the system was developed in ancient China from magical beliefs in the power of bodily parts, the individual, as it were, sacrificing his finger in good faith of his promises; in its origin, the fingerprint had a magical and ritualistic character.

Sir W. Herschel states that he fails to see the definite force of the word "identification" in the Chinese finger-print system. In his opinion, there must be two impressions at least, that will bear comparison, to constitute "identification." He thinks, of course, onesidedly of the detection of criminals to which the process has been applied by us, but never in the East (for what reason, I have stated elsewhere). Most certainly, the idea underlying Chinese finger-prints was principally that of identification, as expressly stated by Rashid-eddin and all Chinese informants. If a doubt or litigation arose, all that was necessary was to repeat the finger impression of the contractor who had formerly signed the deed. B. LAUFER

FIELD MUSEUM, CHICAGO, ILL.

SPECIAL ARTICLES

ON THE COLLOID CHEMISTRY OF FEHLING'S
TEST
I

As familiarly known, when Fehling's solution is treated with a reducing substance, it is generally expected that a bright red precipitate will be obtained. Frequently, however, an orange or yellow precipitate is obtained and in certain instances nothing but a yellowishgreen or bluish-green discoloration results. The attempts to account for these differences are, for the most part, chemical in nature; it is held that the red reaction represents a precipitate of cuprous oxide, the orange or yellow ones more doubtful suboxides or hydrated forms of the oxide, while the character of the greenish discolorations is left doubtful. It is often be

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