by a simultaneous gliding of its whole mass, as believed by de Saussure. All these laws, deduced from a first, but attentive, study of the phenomena of the glaciers, were, at that time, — excepting that of the moraines, new for science. They were expounded by me, and illustrated by diagrams, at the meeting of the geological society of France, in session at Porrentruy, the same summer of 1838; and I had the great satisfaction of seeing them fully confirmed by the subsequent observations of Agassiz and others, which furnished the precise numerical data then wanting for their complete elucidation. This paper, however, though duly mentioned in the proceedings of the geological society (Bulletin, vol. ix. p. 407), was not printed, owing to a protracted illness of its author in the winter following But on the occasion of a claim by Prof. J. D. Forbes to the discovery of the laminated, or ribboned, structure of the ice, the portion relative to this subject was printed, and the whole manuscript, on a motion of Agassiz, was deposited, by a formal vote, as a voucher, in the archives of the Society of natural sciences of Neuchatel, the original draft being now in my hands. If I mention this circumstance, it is because the regrettable omission of the publication of my paper was the occasion of the unfortunate misunderstanding which estranged two such men as Agassiz and Forbes, and which I feel bound. iu a measure, to explain."

The manuscript referred to in the latter part of this citation was sent to the Society of natural sciences of Neuchatel early in 1883, was read at the session of the society on the 12th of April, 1883, and published in its Bulletin of the same year. I have a copy of the published paper, which I received from the secretary of the Neuchatel society. It is in French, as first written, and its title page, and also the cover, bears the heading, Observations sur les glaciers des Alpes en 1838, par M. Arnold Guyot.' I had thus. in Guyot's memoir of Agassiz, and this publication by the Society of natural sciences of Neuchatel, the fullest authority for my statements, and also, in this and other ways, abundant reason for confidence in Professor Guyot. Moreover, his memoir of Agassiz bears evidence throughout that his friendship for Agassiz, as I know from long and intimate intercourse with him, was, to the end, that of a brother.

In the same memoir, Guyot says of Venetz and Charpentier names mentioned by Mr. Marcou and of Agassiz's great results :

"If to Venetz and Charpentier belongs the honor of having first proved the transportation of the Swiss erratic bowlders by the agency of ice, and the existence of great glaciers formerly extending to the Jura, to Agassiz we must accord the merit of having given to these facts their full significance; of having brought them before the world at large, and having made the glacial question, as it were, the order of the day. By his sagacity he found glacial action where it was never suspected before, pointed it out to the astonished and unbelieving English geologists on their own soil; found it in North America; traced it with undoubted evidence in the temperate regions of South America; and believed, though with hardly sufficient reason, that he had seen it on the vast plains of the Amazon. He proved the phenomena to be well-nigh universal." Thus Guyot does justice to his friend, and recognizes the earlier work of Venetz and Charpentier.

My academic memoir of Guyot closes with the fol

lowing sentence: "As fellow-students, we have special reason to admire in Guyot -as he wrote of Humboldt-'that ardent, devoted, disinterested love of nature, which seemed, like a breath of life, to pervade all his acts; that deep feeling of reverence for truth, so manifest in him, which leaves no room for selfish motives in the pursuit of knowledge, and finds its highest reward in the possession of truth itself.'" I know this to be a just tribute.

Mr. Marcou's remark condemnatory of Professor Agassiz's successor at Harvard college,' for "having denied, in toto, in a publication founded by Agassiz, The memoirs of the Museum of comparative zoology,'- his [Agassiz's] great discovery of the 'ice age,' but having, more than that, ignored him altogether as the discoverer of the existence of ancient glaciers in the British Dominions, in New England and New York, in Brazil, in the Straits of Magellan, and in Chili," is essentially groundless. 'The memoirs of the museum,' referred to, contain, among its volumes, a work entitled 'The climatic changes of later geological time, by J. D Whitney,' and this is the only ground presented by Mr. Marcou for the charge he makes. Mr. Whitney's work opposes accepted views on ancient glacier distribution, and therein opposes Agassiz, and nearly all geologists living; but he has not a word of disparagement for Agassiz, and gives no just cause of personal complaint. Mr. Marcou's charge against Mr. Alexander Agassiz has no other foundation, and is not true to the views he holds, and has always held, with regard to his father's work and discoveries connected with glaciers and the 'ice-age.' The memoirs of the museum of comparative zoology, founded by Mr. Alexander Agassiz, and not by his father, has been for some time sustained, and the museum work carried on, with the grandly generous outlay on Mr. Agassiz's part of several hundred thousand dollars; and he has never made the stipulation, which the objector seems to require, that the publications should contain nothing in opposition to his own, or his father's opinions.

New Haven, Aug. 11.

JAMES D. DANA.

Lacustrine deposits of Montana.

The examination of the Gallatin valley in Montana, by the writer, under the supervision of Dr. F. V. Hayden, during the summer of 1885, has developed some points of general interest in relation to the old lake basins of that region. Dr. Hayden was the first to demonstrate the fact that the western country, during the tertiary period, was covered to a greater or less excent with lakes, the waters of which, as the tertiary period progressed, gradually changed from brackish to fresh; until in pliocene time there were numerous fresh-water lakes scattered all over the area of the west, from the Mississippi valley to the Pacific coast.

The first of the basins described by Dr. Hayden was the one lying east of the Rocky Mountains, and extending from the Niobrara River to an unknown distance south of the Platte River. He estimated that this lake must have occupied an area of from 100,000 to 150,000 square miles. To the beds deposited in this lake the name of the Loup Fork group was given; and they were found to shade imperceptibly into an upper group, to which he gave the name of Post-Pliocene, the lower strata having been

others. Will we not, therefore, have to cut down very materially the great length of time generally believed to have elapsed in this region from the beginning of this lacustrine period to the present time, when we find that a great portion of the sediment that once filled the lakes is due, not to the products of erosion, as has hitherto been supposed, but to repeated showers of volcanic dust? Again, do not these volcanic materials, which must have fallen in showers over a large extent of country,-accumulating in some cases in beds forty to ninety feet thick, -account for the perfect preservation of the vertebrate remains which characterize the formations in so many parts of the west; and is there not also suggested one possible cause for the extinction of some of the many groups of animals which have at present no descendants in this region, and whose only remains are the bony fragments found in these lacustrine deposits?

U. S. geological survey.

A. C. PEALE.

Carnivorous prairie dogs.—Carnivorous orioles.

The statement of R. W. Shufeldt that his pair of young prairie dogs took kindly to a meat diet (Science, viii. p. 102) attracted my attention and interest, for it recalled to my mind an experience of my own in the summer of 1838. Having a pair of the marmots at this moment under observation here, I determined to try them with a piece of raw beef, and the eagerness with which they plunged at it (for their avidity cannot be characterized by any milder word) was certainly something very astonishing. Their ordinary vegetable food they take quietly, but the beef seemed to set them frantic. They acted as though they were famishing, they seized it so fiercely, fighting with one another for it, and hastening back to ask for more. And so it has continued. Their owner fears to feed them with it exclusively, but gives them more or less daily, and the contrast between their eagerness for the meat and their quiet consumption of vegetables is a very instructive lesson. Their stomachs, out on the plains, always hold vegetable contents and nothing else. This was doubtless the first piece of meat ever tasted by either of these. Whence this craving appetite?

The experience of 1838 to which I referred was this: That was in the earlier days of my 'natural history,' three years before my first ichthyological paper was written. I had taken three young Baltimore orioles from their nest, but feared that I should lose them, for they refused every variety of food I offered them. At that time I was collecting birds zealously, and was skinning several of them daily. As I was preparing a specimen, one of the young orioles was sitting on my table, very stupid indeed, head drawn in, not life enough to utter a sound, thoroughly dumpish. Without knowing why, I picked up a bit of the bird's flesh and offered it to him. To my great surprise he swallowed it on the instant, and roused himself at once. That one mouthful had done him so much good that he wanted more. I took him on my finger and fed him piece after piece, till his throat was swelled out like au over fed chicken's crop, and I feared to give him more. He settled himself down with great satisfaction, and went to sleep. I fed his brother and sister in the same way; and from that time till they were fully grown they had not a mouthful of food except

the flesh of the birds I was skinning. Their eagerness for the meat was extreme. They learned the bird-skinning business to perfection. As soon as they saw me prepared for work, they all gathered about the specimen, ravenous for meat, and I almost always commenced to skin my bird, with an oriole sitting on each hand, and one on the specimen itself, and with three little heads down over the abdomen, where the first cut was to be made (they knew the point well enough); and the instant I opened the skin, in went three bills, digging and tearing fiercely for their food, and continuing at it as I continued my work, till their appetites were satisfied.

I do not know that this fact concerning the Baltimore oriole has ever been reported. I recollect mentioning it to Mr. Audubon, but it was after his account of the species had been published. New London, Conn., Aug. 11.

Flooding the Sahara.

W. O. AYRES.

In our own country an evaporation of two feet per year is a small figure, and twice that amount has been recorded in some cases; so that it would seem to be safe to assume that it would exceed the latter value in the north of Africa. Taking Mr. LeConte's figures (Science, vol. viii. p. 35), and an evaporation of two feet per year, and the cubic feet evaporated, on an area of 3,100 square miles would be 2 x 864.230 × 105 cubic feet = 1,728,460 × 105 cubic feet per year. But the inflow, according to his assumptions, would be 1,262,277×10 cubic feet per year; so that at the rate of two feet of evaporation per year, the amount evaporated would be 1.3 times the amount of the inflow. In other words, at the rate of inflow assumed, the depression to be flooded would never be so far filled as to make a surface of 3,100 square miles and if the evaporation be four feet per year, the inflow would necessarily be nearly three times that assumed by Mr. LeConte. DE VOLSON WOOD.

Hoboken, Aug. 14.

Barometer exposure.

No

The discussions in Science relating to the effect of high winds upon the indications of a barometer in a room, have been highly interesting. I only desire at this time to present a few facts that bear upon the problem, and to correct a few misconceptions one that has attempted making a fire in a very cold room, on a very windy day, with a refractory chimney in the fore ground, can be easily convinced that there is much of a draft up a cold chimney, even with a hurricane. Even if there were such draft, the air must flow in through all the cracks, especially on the windward side, and equilibrium would thus be kept up. It should be noted also that the wind does not blow steadily, but rather in gusts; consequently there can be no such thing as a permanent lower pressure inside than outside a room, but a momentary depression by a gust would be relieved almost immediately by the lull.

This is shown beautifully by a barograph properly arranged. All references will be to a barograph inclosed in a tight glass case, such as has been adopted by Mr. Hough of Albany. The fluctuations are so rapid that they cannot be seen on a sheet carried at the rate of one to two inches per day, but only upon

one carried from seven-tenths of an inch to one inch per hour. In the latter case, with a very high wind sometimes, but rather the exception, there will be seen fine serrations, at intervals of one or two minutes, having the appearance of a very fine saw. These serrations are quite regular, and are seen only during the high wind. The greatest fluctuation cannot be more than eight one thousandths of an inch and seldom are above four one thousandths to six one thousandths. It is probable that the wind influences these fluctuations, but it is very difficult to determine just how. That a high wind does not always produce them is quite remarkable. Returning to our drawing chimney, it would seem an interesting computation as to how long a gust would need to last in order to draw out of a chimney one foot square sufficient air to produce the supposed depression.

If we consider that the barograph is inclosed in an almost air-tight case, we have still another addition to our problem. Even if there were a withdrawal of air from the room, is it possible for the influence to reach the inside of the case before the lull has made a change? A partial answer to this question may be had by experimenting with the case. If the door be opened rather suddenly a partial vacuum is formed, or a jar occurs, which moves the float, and the pencil falls or rises according as the barometer has previously had a tendency down or up. This effect is only two one-thousandths of an inch; and it is very rare that an influence greater than that can be brought to bear upon the apparatus under these conditions. It would seem as though the effect produced by opening or closing the case may be many times greater than the utmost that can come from an intermittent wind.

If we turn to the original letter by Mr. Clayton (vol. vii. p. 484), we shall find these particular cases given by him: 1°. "On March 16 the wind's velocity rapidly rose from five to thirty-five miles, and the barometer suddenly fell five one hundredths of an inch;" 2°, "During a sudden gust attending a shower, last summer, the barometer fell a tenth of an inch, and immediately rose again as the gust ended;" 3°, "It [the pressure] fell as much as a tenth of an inch during a seventy-mile wind in February." It will be seen that each of these cases occurred under abnormal conditions, and just at the time when we would naturally expect such fluctuations; but they can hardly be due to the wind, as they are often noted when there is no high wind. The wind's action is intermittent, and there is no evidence whatever of this most important fact making itself known. It is a matter of regret that Mr. Clayton did not open and shut his trap-door at intervals of five or ten minutes, for an hour or so. He would have settled the question beyond doubt if he had done this.

Much has been written in regard to the evidence of observations on Mount Washington. Mr. H. A. Hazen has given a partial discussion of the Mount Washington records in the Annual report of the chief signal officer,' for 1882. He there has shown that the effect of the wind upon the computed elevation changes sign at a velocity of twenty-five to thirty miles per hour; i. e., instead of the effect being zero when there was no wind, it was really zero with a wind of twenty-five to thirty miles per hour. This is a fair indirect proof either that the wind does not cause the fluctuation, or, if it does, that another force is superposed upon it.

It is hazardous drawing conclusions upon the facts

thus far developed. It may be that the wind can produce more than one effect, and that the serration effect above alluded to is not the only one to be considered. The weight of evidence seems to be rather against any great depression being produced. Mr. Clayton will do meteorology a great service by trying a few experiments. If his barograph, shut, is carried along only two inches a day, opening the trap door ten minutes will give only one seventy second of an inch for the pencil to move in. The difficulty can be obviated, however, by letting an attendant note the movement of the pencil (if there be any) and carefully take the time of the fluctuations, if the time of manipulating the trap-door be also taken, a comparison of times will settle the question.

Aug. 10.

A case of inherited polydactylism.

GAN.

In the spring of 1883 I saw and examined a case of inherited polydactylism, which I think worth recording. While enjoying the hospitality of a friend, in a charming ravine opening into Napa Valley from the mountains on the west side, my attention was drawn, by my intelligent hostess, to the hands of a German laborer at work in the garden. There were six wellformed, usable fingers on each hand. The metacarpals were of the normal number, but the fifth bore two fingers. The supernumerary little finger differed from the true little finger only in being much smaller.

AUGUST 20, 1886.]

cially of the thumb. Indeed, a proposition has been made to use this characteristic for identifying the Chinese emigrants to California. In Germany, especially, attempts have been made to show that these markings have racial significance. Has it ever been noticed that this custom has been borrowed from China, where the thumb and finger markings are used for purposes of identification, and by illiterates in signing papers? In the Proceedings of the China branch of the Royal Asiatic society,' for 1847, p. 11, is an article on land-tenure in China, by Thos. T. Meadows. Appended to this article is a copy of a deed bearing the thumb-signature of the grantor, a woman. Chinese sailors shipping on junks are made to sign with five fingers, in order to get a more certain identification. Dr. D. B. McCartee informs us that the Chinese class the striae at the ends of the fingers into 'pots' when arranged in a coil, and 'hooks' when they form a curving loop. They say that two men's thumbs may be alike, but that it is hardly possible that their hands would make similar pot-hooks.

U. S. national museum, Aug. 10.

WALTER HOUGH.

167

nerve-fibre courses in these small brains, a difficulty which has been to a great extent removed by improved microscopic methods; second, from the following fact: the anterior commissure in the mammalian brain consists of two divisions, one going to the olfactory lobes, the other to the temporal lobes. Recent authors have been led to confuse the commissure which really represents the corpus callosum, with the first-mentioned division of the anterior commissure, the truth being that the distribution of this commissure has never been precisely observed.

During the past winter I had an opportunity of studying the cerebral commissures in types of all the lower orders, in the most thorough manner; and found that the corpus callosum, so far from being a structure peculiar to the mammals, is present in the reptiles, birds, and Amphibia, and probably also in the Dipnoi and other fishes. In short, this commissure is a primitive character of the vertebrate brain. An account of the steps which led to this conclusion would exceed the due limits of this article, but an outline of the results may be given.'

For our present purpose, we must recall the embryonic position of the mammalian corpus callosum

as a delicate bundle, traversing the thin wall which unites the hemispheres, and known as the 'lamina terminalis.' Below this, in the lamina, is another fibre-bundle, the anterior commissure. In the placental mammals, these bundles, from the time of their first development, are separated by an interval or pn pcm IV

mf

FIG. 2.-A vertical section of the turtle's brain (Emys Europaea).

septum; but in the marsupial brain, at an early stage, they lie close together in the middle line, very much as they are represented in fig. 3, in the turtle's brain (cal and aem), the upper bundle bending upwards, like a horseshoe; the lower passing outwards in the floor of the lateral ventricle (lv).

In the brain of the frog, in vertical section (fig. 1), we observe two bundles similarly placed in the lamina terminalis. The lowermost (acm) consists of two parts of unequal size, the larger part passing for1 See Morphologisches jahrbuch, xii, August.