Popular Science Monthly/Volume 10/December 1876/Miscellany
Distribution of Plain, Prairie, and Forest.—In the American Naturalist for October, Prof. J. D. Whitney gives a very elaborate critique of the various hypotheses which have been put forth to account for the distribution of plain, prairie, and forest, over the North American Continent. The author has no theory of his own to offer, but he appears to show conclusively that none of the accepted theories can be regarded as satisfactory. One of the theories examined by Prof. Whitney is that which attributes the existence of forest, prairie, or plain, to the distribution of rainfall throughout the year, or from season to season. As stated by the late J. W. Foster, this theory holds that "wherever the moisture is equable and abundant, we have the densely-clothed forest; wherever it is unequally distributed, we have the grassy plain (prairie); and where it is mostly withheld, we have the inhospitable desert." This last proposition Prof. Whitney admits, the other two he pronounces erroneous. He cites the vicinity of Chicago, where Mr. Foster lived, in proof of the incorrectness of that author's views. "Here," says Prof. Whitney, "we have the finest prairie-regions in the world, absolutely destitute of trees, and yet in the full enjoyment of an abundant precipitation, and in the immediate vicinity of an immense sheet of water. For Chicago itself, indeed, the statistics of rainfall are very defective, but, such as they are, they are entirely unfavorable to Mr. Foster's hypothesis. Points in the immediate vicinity of that city, where observations have been taken for a series of years, show an average rainfall of thirty-six to fifty inches, pretty uniformly distributed through the year. An excellent instance, on the other hand, of a dense growth of trees combined with the most unequally-distributed rainfall which is possible, is furnished by the western slope of the Sierra Nevada, in California, whose magnificent forests are well known, as also is the fact that there is no precipitation there at all for six months of the year, nearly the whole of the rainfall being limited to three months. And, lest it may be thought that melting snow keeps the ground moist during the summer, it may be added that the heaviest forest-belt of the Sierra is quite below the line above which snow rests for any considerable time, and that the soil in that belt is usually perfectly dry at the surface, and even dusty, for six months of the year, and often much more."
Electrical Phenomena exhibited by Venus's Fly-Trap.—The electrical phenomena exhibited by Dionæa muscipula have been investigated by Dr. Burdon-Sanderson, who finds that normally the whole leaf with the petiole is somewhat negative, but, when excited by a stimulus, an electrical change takes place throughout, making every part more negative. The greatest change is on the external surface of the leaf, immediately opposite to the three sensitive hairs. There is no relation between the preexisting currents and the electrical disturbance consequent on stimulation. The period of latent stimulation (i. e., the space of time occupied by the primary action of the stimulus) is about one-sixth of a second. The period during which the disturbance lasts is about one second. As the leaf becomes fatigued, the period of latency increases to one second and three-quarters, and then most likely the next stimulation produces no effect. The change appears to be a function of the protoplasm of the parenchyma of the region out of which the sensitive hairs arise. Certain of the characters of the change are similar to those presented by muscle and nerve. Why the variation should be a negative one, Dr. Sanderson is unable to determine.
New Shells from Colorado.—In the extensive and remarkable display of natural-history objects brought to the Centennial Exhibition by Mrs. M. H. Maxwell, of Boulder, Colorado, was a box of land and fresh-water shells. These have been examined by Mr. Ernest Ingersoll, who made careful studies of the Rocky Mountain mollusks in connection with the United States Geological Survey in 1874, and summarized his results in an article printed in this magazine for May, 1876. Boulder is at the mouth of Boulder Cañon, several miles northeast of Denver, at an altitude of about 5,530 feet above the sea, and on the eastern slope of the main range, where heretofore no shells had been found. The list includes Zonites arboreus, Z. fulvus, Patula Cooperi (living, and very dark and fine), P. striatella, Helix pulchella, Cionella subcylindrica, Vertigo ? (very minute), Succinea lineata, S. Nuttalliana, Limnea palustris, L. desidiosa, L. humilis, Physa heterostropha, Planorbis bicarinatus, P. tumens, Helisoma plexata, Gyranlus parvus, Ancylus ?, Goniabasis liveseens, G. pulchella, Sphærium striatinum, Pisidium abditum, and an anodon hardly identifiable.
The collection is remarkable, as coming from the eastern slope of the range, and embracing some unexpected species from east and west. As usual, the Physas are Protean in form, and one can make half a dozen "species" out of them, if disposed. Some of them are well-marked "Inflata." Both the planorbs are reported for the first time from Colorado. P. bicarinatus is a well-known Eastern shell; P. tumens has hitherto been supposed to be confined to Northern Mexico and Southern California. The Helisoma is a new form, discovered by Mr. Ingersoll in an isolated mountain-lake in the southern part of the State, and Mrs. Maxwell finds it at Boulder in a similar situation. Both the Melanians and the Sphærium are additions to the fauna of the State, and the Anodonta will probably prove to be undescribed. Mrs. Maxwell proposes to search still more carefully when she returns, and further information on the geographical distribution of our mollusks in the mountainous territories may be expected from various other quarters where research has been stimulated by the curious results already brought out. Colorado seems to be a meeting-ground for mollusks from all directions, and is a promising field for the collector and student.
Marey's Experiments on the Action of the Heart.—Experiments made by Marey show that a diminution of excitability and a rise of temperature in the muscular tissue of the heart invariably coincide with the cardiac systole, while the opposite phenomena are manifested during diastole. The same author has recently attempted to ascertain whether any corresponding variations of the cardiac muscle could be made out. The galvanometer, owing to the inertia of its needle, is unsuitable for the observation of sudden changes in the intensity of currents. Hence, in Marey's experiments, Lippmann's electrometer was employed. The heart of a frog was placed on two unpolarizable electrodes, one supporting the apex of the ventricle, while the auricles rested on the other. Two successive negative variations of the current were indicated by the electrometer during each cardiac systole; one of these was sudden, and corresponded with the abrupt contraction of the auricles; the other was more gradual, and coincided with the slower movement of the ventricle. The phases of electrical variation are thus seen to be similar to those of the work done by the muscle.
College Exploring Expeditions.—We learn from the Tribune that the present Senior Class of Princeton College has organized a scientific exploring expedition to the West. An association has been formed to train men in scientific studies, and fit them as far as possible for the work to be done. The plan of the association's work is as follows: A knowledge of geology, as good as can be obtained, is required of each man. Then the work is mapped out into subdivisions of natural history and paleontology, and from these each one selects a specialty for himself. The meetings are held fortnightly. At these, the association generally receives an address from some scientific member of the faculty. After this, scientific papers are read by the members, in alphabetical order, four each evening. A question chosen at the previous meeting is then discussed. The faculty have given a room, have arranged the studies to help the association as much as possible, and given facilities for special and outside work. The association is forming a working collection of fossils and minerals, not intended to be complete, but typical. In the mean time the executive committee are taking steps to secure government aid in the shape of wagons, mules, etc., and to get the most favorable possible terms from the railroad companies. If, as is hoped, the committee is successful in obtaining free passes, the expenses will probably not exceed $100 per man. It is not yet fully determined what portion of the West will be explored—probably, however, the Green River, in Wyoming Territory, and Yellowstone National Park, or else the Wahsatch Mountains, will be selected. The membership is limited to thirty regular and ten alternate members. Vacancies occurring in the regular membership are filled from the alternates, who attend all meetings, and perform regular duties.
Eucalyptus as an Anti-Periodic.—Two instances are cited by Dr. Curnow, of London, of the cure of intermittent fever by the use of tincture of Eucalyptus globulus. We give in full the author's account of one of these cases, as sufficiently illustrating the action of the drug: S.S, aged eighteen, a Norwegian, was admitted to King's College Hospital, May 23, 1876. He had been suffering from intermittent fever for four or five weeks. The attacks were moderately severe and of a well-marked tertian type. An expectant plan of treatment was pursued until June 9th, and during this period the paroxysms recurred on alternate, days with the utmost regularity. They began at 10 a. m., reached their acme between 1.30 and 3 p. m., and passed off about 6 p. m. The highest temperatures varied from 104.8° to 105.6°. On June 9th the tincture of the Eucalyptus globulus was given in one-drachm doses three times daily. The next day, on which another attack was due, his temperature rose to 100°, and on the 12th to 100.4°; and after this date no further paroxysm occurred during the remainder of his stay in the hospital.
Improvements in Iron-Manufacture.—Dr. Andrews, in his inaugural address at the Glasgow meeting of the British Association, referred to the many improvements recently introduced in iron-manufacture. But there yet remains, he said, ample work to be done. The fuel consumed in the manufacture of iron, as indeed in every furnace in which coal is used, is greatly in excess of what theory indicates, and the clouds of smoke which darken the atmosphere of English manufacturing towns, and even of whole districts of country, are a clear indication of the waste, but only of a small portion of the waste, arising from imperfect combustion. The depressing effect of this atmosphere upon the working-population can scarcely be overrated. At some future day the efforts of science to isolate, by a cheap and available process, the oxygen of the air for industrial purposes, may be rewarded with success. The effect of such a discovery would be to reduce the consumption of fuel to a fraction of its present amount; and, though the carbonic acid would remain, the smoke and carbonic oxide would disappear. In the mean time, Dr. Andrews suggests that in many localities the waste products of the furnace might be carried to a distance by a few horizontal flues of large dimensions, terminating in lofty chimneys on a hillside or distant plain, as is done at the mercury-mines of Idria and some other places. With a little care in the arrangements, the smoke would be wholly deposited in the horizontal flues, and would be available for agricultural uses.
The Tomato-Plant as a Protection against Insects.—In a peach-orchard planted by M. Siroy, a member of the Valparaiso Society of Horticulture, the trees at first grew well and strongly. But, on commencing to bud, they were invaded by the curculio; and this insect was followed, as frequently happens, by ants. While the trees were thus infested, the idea occurred to M. Siroy that by placing leaves around the trunks and branches he might ward off the rays of the sun, which were very powerful. For this purpose he happened to choose tomato-leaves. On the following day he found the trees entirely free from their enemies, not one remaining, except here and there where a curled leaf prevented the tomato from exercising its influence. These leaves he carefully unrolled, placing upon them fresh ones from the tomato-vine, with the result of banishing the last insect, and enabling the trees to grow with luxuriance. Wishing to carry the experiment still further, he steeped in water some fresh leaves of the tomato, and sprinkled with this infusion other plants, roses and oranges. In two days these were also free from the innumerable insects which covered them.
The Age of Paleolithic Man.—Dr. R. H. Tiddeman contributes to Nature for October 5th a paper in which he reaffirms the inter-glacial age of paleolithic man and of the fauna with which he is associated. The position not only of human but of animal remains points clearly to the fact of their existence subsequent to a deposit of glacial drift, but previous to another deposit of similar material. The facts may be taken as part of the evidence which proves the disappearance of a great ice-sheet which covered Scotland, England, and portions of the Continent, and the return of it after a period of temperate climate during which man and animals inhabited the region.
The direct evidences of the inter-glacial age of paleolithic man from the actual infraposition of his bones or implements are stated as follows:
1. Victoria Cave, Settle: a human fibula under glacial till, and associated with bones of Elephas antiquus, Rhinoceros leptorhinus, hyena, hippopotamus, etc.
2. At Wetzikon, Canton Zürich, a piece of lignite containing basket-work lying beneath glacial deposits, and associated with Elephas antiquus and Rhinoceros leptorhinus.
3. Near Brandon, Suffolk, implements with bones not yet determined in brick earth beneath the great chalky bowlder clay of East Anglia.
Dr. Tiddeman says the "Settle till is undoubtedly of the age of the ice-sheet. The Wetzikon lignite lies upon a glacial till beneath a river-gravel on which are great erratic blocks clearly indicating the presence of a great glacier posterior in date to the organic remains. The Brandon implements are beneath the chalky bowlder clay."
Inequality of the Ocean-Bed.—In opening the Geographical Section of the British Association at Glasgow, Captain Evans said that it was learned for the first time by the Challenger's results—ably supplemented as they had recently been by the action of the United States Government in the Pacific, and by an admirable series of soundings made in the exploratory German ship-of-war Gazelle—that the unbroken range of ocean in the southern hemisphere was much shallower than the northern seas; that it had no features approaching in character those grand abysmal depths of 27,000 and 23,500 feet found respectively in the North Pacific and North Atlantic Oceans, as the greatest reliable depths recorded did not exceed 17,000 feet. The general surface of the seabed presented in general to the eye, when graphically rendered on charts by contour lines of equal soundings, extensive plateaux varied with the gentlest of undulations. There was one great feature common to all oceans, and which may have some significance in the consideration of ocean circulation, and as affecting the genesis and translation of the great tidal wave and other tidal phenomena, of which they knew so little—namely, that the fringe of the seaboard of the great continents and islands, from the depth of a few hundred feet below the sea-level, was, as a rule, abruptly precipitous to depths of 10,000 and 12,000 feet. This grand escarpment was typically illustrated at the entrance of the British Channel, where the distance between a depth of 600 feet and 12,000 feet was in places only ten miles. Imagination could scarcely realize the stupendous marginal features of this common surface depression.
Purification and Deodorization of Petroleum Products.—Mr. S. E. Johnson, of Ashby-de-la-Zouch, England, has discovered a method of treating petroleum and other mineral oils, by which those useful hydrocarbon liquids are not only purified, but also deodorized; and that in a simple and inexpensive manner. Chloride of lime is first introduced into the cask or other receptacle containing mineral oil or spirit, in the proportion of about three ounces of chloride, more or less, to each gallon of the liquid, according to the degree of its impurity, and thus chlorine-gas is evolved in the oil or spirit. If necessary, the evolution of the gas may be assisted by pouring in hydrochloric acid, agitating the contents of the receptacle so as to bring the whole of the liquid into intimate contact with the chlorine-gas. The oil or spirit is then passed into another inclosed vessel containing slaked lime, which, having an affinity for the chlorine, absorbs the same, leaving the liquid sufficiently deodorized and purified.
Physiological Effects of Coca.—A correspondent of the Lancet, a physician, states that the use of the tincture of coca, in a two-ounce dose, corrected the "unruly throbbing" of his heart, which had been wont to interfere with his accuracy of aim in fowling. This writer had previously taken the tincture in doses of one-half ounce and one ounce without perceptible effect; but, having on the third day increased the dose to two ounces, his composure was perfect at the critical moment. "As soon as the dogs pointed," he writes, "I expected the usual inward commotion, with its usual results; but, to my surprise, nothing of the kind happened. 'Eureka!' I said to myself; 'the coca has made me a steady shot.' So in fact it subsequently proved. Judged by the effects described," he continues, "coca would seem to be inhibitory as regards the action of the heart. Whether this result is produced by indirect action through the mental functions upon which the drug is said to act remains to be proved." Another correspondent of the same journal, not a physician, states that while traveling in Bolivia at great altitudes, such as from 13,000 to 14,000 feet above the sea-level, he experienced marked benefit from eating the leaves. Nearly all travelers on the Peruvian and Bolivian Andes use the drug as a remedy for that effect on the brain and lungs, produced by rarefied air, which in South America is called zorroche. One use to which it is put by the Indians is that of a "pick-me-up" after a debauch on alcoholic fluids. In Bolivia it is generally eaten with a paste made of wood-ashes and potato. The writer propounds the belief that the leaf loses its virtue in transmission. This is quite possible. It is an undoubted fact that the Cannabis Indica, for instance, loses its potency in crossing the sea. It would seem desirable that a certain quantity of the coca-leaves should if possible be packed in an air-tight case. The price of coca at La Paz, where the best is procured, was last year sixteen dollars per packet of twenty-five pounds.
The American Forestry Association.—The American Forestry Association held its first meeting at Philadelphia in September. Addresses were delivered by Dr. Franklin B. Hough, of Lowville, New York, Mr. McAfee, and Mr. Meehan. Dr. Hough gave an account of the efforts made by various European governments to preserve forests and to promote timber-culture, and showed that the Constitution of the United States, and those of most of the States, give the right to interfere for the preservation of our forests. Mr. McAfee reported on the condition of forest-culture in the West, showing how the planting of trees had been going on to an immense extent, and that it was found that the old notions about the slowness of timber growth had been derived from the hard struggle with Nature that wild timber had to make. Cultivated trees had grown so much faster than was expected that people had been surprised at the growth, and it was now becoming generally known that wood came into profit much sooner than was thought possible years ago, and forest culture was much more popular in consequence. In his State at least 80,000 acres of timber had been planted during the past few years, and the work was still going on. He gave figures as to the growth of individual species, chiefly from facts within his own observation. Mr. Meehan, from whose Gardener's Monthly we take this account of the meeting, thought that the people, without government interference, can be safely trusted with the care of our forests, and the work of reforestation. Individual effort, encouraged by State laws and agricultural and horticultural societies, would soon replace the decaying forests of our land.
How the Menopoma casts its Skin.—Since reading his "Preliminary Note on the Menoponia Alleghaniense of Harlan," before the American Association, Grote has observed in the aquarium of the Buffalo Society of Natural Sciences the process by which the menopoma rids itself of its outer skin. This thin and transparent membrane is first seen to loosen and separate from the entire surface of the body, appearing at this stage like an envelope or glove in which the animal is contained. By a number of wide gapings, during which the mouth is opened to the fullest extent, the skin is parted about the lips, and then commences to fold backward from the head. Convulsive and undulating movements with the body and fore-legs are employed to extract these from the loose skin. The skin then readily falls backward, as the animal crawls forward and out of it, until the hind-legs are reached, when the menopoma turns round upon itself, and, taking the skin in its mouth, pulls it over the legs and tail. The operation reminds one of taking off clothes. The cast-off skin is retained in the mouth and finally swallowed. The operation is quickly performed.
Poisonous Cooking-Utensils.—The danger attending the use of porcelain-lined cooking-vessels was pointed out at a meeting of the British Society of Public Analysts, by Mr. Robert R. Tatlock. He stated that the milk-white porcelain enamel with which cast iron cooking-vessels are now so commonly coated is in the highest degree objectionable, on account of the easy action on it of acid fruits, common salt, and other substances, by means of which lead and even arsenic are dissolved out in large quantity during the process of cooking. It was shown that it is not so much on account of the presence of large proportions of lead and arsenic that these enamels are dangerous, but because they are so highly basic in their character, and are so readily acted on by feebly-acid solutions. He thought that no enamel should be admitted to use unless it was totally unaffected by boiling with a one-per-cent. solution of citric acid, which was a very moderate test. Further, he gave it as his opinion that either the use of such poisonous ingredients as lead and arsenic in large quantity should be entirely discontinued, or that the composition otherwise should be of such a character as to insure that none of the poisonous substances could be dissolved out under ordinary circumstances.
Agencies that formed the Colorado Cañons.—The great cañon of the Colorado is from 3,000 to 6,000 feet deep, through a distance of 200 miles. All the side-streams reach it through profound canons, and each stream has done, and is still doing, its own work of erosion. The process by which these results are brought about is considered by Prof. G. R, Gilbert, in the American Journal of Science and Arts, under three principal heads: 1. Weathering; 2. Transportation; 3. Corrasion.
By weathering, the writer means the disintegration of rock by the action of temperature—beating of rain and changes of vegetation. The process, however, would be greatly delayed if the loosened material was allowed to remain and cover the surface. Hence transportation becomes a powerful agent in erosion, not only by exposing the disintegrating surfaces, but by mechanical wear in the act of removal.
All rocks are more or less soluble in water, and impurities in the water intensify solvent action. But it usually happens that rocks disintegrated in this way merely fall to pieces, the hard portion remaining in the shape of sand or pebbles. The transportation of this by streams produces what the author calls corrasion. In this way the bed of a stream is widened and deepened, but the work is also facilitated by the ceaseless action of water in dissolving the rocks.
The mechanical wear or erosion by a stream depends largely on its velocity. "A stream of water flowing down its bed expends an amount of energy that may be measured by the quantity of water and the vertical distance through which it descends."
The velocity of a stream would continually increase if none of its energy was consumed in friction, but very much of it is so consumed, and reappears in innumerable forms of movement or subsidiary currents. It is by some of these that the work of transportation and erosion is largely done. Bat a stream may be overloaded with detritus, and its corrading power correspondingly diminished. "Only with a partial load does a stream wear its bottom." Of the Colorado plateau the author says that the erosion which began with the first lifting of a part above the ocean has progressed continually to the present time. The total uplift has been about 12,000 feet; only 7,000 feet remains, that being the present altitude above the level of the sea. Five thousand feet of the general surface has been removed, and an amount greater by several thousand feet has been corraded by the rivers.
Improved Railway-Signal.—A simple and effective railroad-signal, in use on the Boston, Lowell & Nashua Railroad, is described in the Scientific American. A single-cell Callaud battery is connected to the two rails at one end of a given section of the line—say, two miles in length—each section being insulated from adjoining sections. At the other end the signal has an electro-magnet similarly connected to the two rails. When the circuit is closed, as is normally the case, the magnet is excited and the signal controlled thereby so as to show that the line is clear. But, when a train runs on the section, then a shorter circuit is made by the wheels and axles, and the current returns to the battery by this course, instead of passing through the signals. The magnet ceases to attract, and the signal by mechanical means is at once turned, to indicate danger. It is obvious that this must occur as long as a single car remains on the track, or when the circuit is broken by a displaced or ruptured rail or any other cause. Hence the device may be applied over an entire line, and will indicate the condition of every section to a train about to enter on the same. It is found to be operative in all weathers.
Powder-Paper.—A substitute for gunpowder has been invented in England, called "powder-paper," viz., paper impregnated with a mixture of potassic chlorate, nitrate, prussiate, and chromate, powdered wood-charcoal, and a little starch. The powder-paper is rolled into the shape of a cartridge of any required length or diameter. The manufacture involves no danger, it is said; no explosion can take place except by way of contact with fire. The powder-paper leaves no greasy residue on the inside of the gun; it also produces less smoke, gives a less violent recoil, and is less impaired by humidity than gunpowder. With equal charges, by weight, of gunpowder and powder-paper, the penetrating power of the latter is 516 greater than that of the former.
October Meteor-Shower.—In a letter to the Tribune, dated October 19th, Mr. Daniel Kirkwood states that shooting-stars in unusual abundance were observed by several trustworthy witnesses at Bloomington, Indiana, on the evening of the 18th, from six hours forty-five minutes to nine hours. The meteors appeared to radiate from Auriga, or rather from a point between Taurus and Auriga. Most of the meteors were small, though two of them possessed extraordinary brilliancy. In a small work on comets and meteors, published three years ago, Mr. Kirkwood called attention to the fact that meteoric showers had been observed at the same period of the year in 1436, 1439, 1743, and 1798. Returns of the shower were observed in 1838 and 1841. He recommends that a careful watch be kept in future about the same period—say, from the 16th to the 20th of October.
Do Plants absorb Diatoms?—Prof. John Phin, in the American Journal of Microscopy, criticises the results of Wilson's microscopic examination of wheat-straw grown on land which had been treated with infusorial earth. The substance of Prof. Wilson's paper we gave in the September number of the Monthly. Prof. Phin reproduces Wilson's engraved representation of the diatom forms said to have been found in the remains of the straw after treatment with nitric acid, and says: "A single glance at the engraving is sufficient to convince any microscopist that Prof. P. B. Wilson never
saw 'upon the field of his microscope,' under the circumstances which he has described, the objects which he has delineated.... Bearing in mind that these organisms, as figured, have been obtained by destroying the organic matter with nitric acid, we find Bacillaria figured as it exists only in the living condition—the frustules being joined together in the peculiar way which has given to this form the specific name paradoxa. For this diatom to have passed through a bath of nitric acid, and come out in the condition figured, would have been almost as great a miracle as the passing of Shadrach, Meshach, and Abednego, unscathed through the fiery furnace of Nebuchadnezzar. So, too, we find a calcareous foraminifer figured under the same circumstances. After such instances, the numerous minor features which are utterly irreconcilable with facts may be safely passed over."
Another Way of securing the Chestnuts.—The following narrative is taken from the Chronique de la Societé d'Acclimation; we give it for what it is worth: "A Frenchman, fifteen years resident in the Transvaal Republic, where he has established a number of plantations, recounts to us the following fact, which no naturalist has as yet reported: The coffee-plantations are much exposed to the ravages of the great cynocephalous monkeys. Among the coffee-plants there grows a shrub, the scientific name of which I have not been able to ascertain, which has its fruit growing very near the trunk. Some wasps, of a kind whose sting is very painful, had chosen several of these bushes for attaching to them their eggs, and the cynocephali were often seen eying the fruit very eagerly, but they dared not touch them for fear of the wasps. One morning, the planter heard terrible cries, and with the aid of a good opera-glass was enabled to witness an interesting spectacle. A fat old monkey, the leader of the troop, would take hold of the young ones, and pitch them repeatedly into the middle of the bush, despite their cries and groans. The shock brought down the wasps' nests, and the irate insects attacked the victims; meanwhile the old rogue quietly ate the fruit, throwing down the remnants of the meal to the females and young ones on the ground."
Taking Impressions of Plants.—M. Bertot, of the Paris Academy of Sciences, offers a simple method of* taking impressions of plants. A sheet of paper is first lightly oiled on one side, then folded in four, so that the oil may filter through the pores, and the plant may not come into direct contact with the liquid. The plant is placed between the leaves of the second folding, and in this position pressed (through other paper) all over with the hand, so as to make a small quantity of oil adhere to its surface. Then it is taken out and placed carefully on white paper; another sheet is placed above, as two impressions can be taken at once, and the plant is pressed as before. On now removing it, an invisible image remains on the paper. Over this you sprinkle powdered black-lead, which causes the image to appear. With an assortment of colors, the natural colors of plants may be reproduced. To obtain fixity, resin is mixed with the black-lead in small quantity; the impression is fixed when it is exposed to a heat sufficient to melt the resin.
Ancient Weapons.—Among the Michigan exhibits of ancient stone and copper implements at the Philadelphia Exposition is a weapon fashioned after the model of the "patu-patu" of New Zealand. It is described by Dr. C. C. Abbott, in the American Naturalist. The patu-patu of New Zealand is, according to Tylor, quoted by Dr. Abbott, "an edged club of bone or stone," in shape "like a soda-water bottle with the bulb flattened. It is a very effective weapon," he adds, "in a hand-to-hand fight, being so sharp that a man's skull may be split at one blow with it." The Michigan specimen is 1614 inches long. It is 258 inches wide for 11 inches; then it tapers to 112 inch, but again widens to 2 inches at the end, thus forming a terminal knob. The edges are beautifully wrought, and are as sharp now as most of the polished stone axes and celts. In the vast collection of relics of American aborigines at Philadelphia Dr. Abbott finds no other specimen of the form here described, and it is presumable that this weapon was one seldom fashioned in North America.