Popular Science Monthly/Volume 19/July 1881/Popular Miscellany
POPULAR MISCELLANY.
Meeting of the American Association.—The thirtieth meeting of the American Association for the Advancement of Science will be held in Cincinnati, Ohio, beginning August 17th. A large and efficient local committee is making all possible arrangements for the success of the meeting, in order that it may be the largest and most important scientific meeting ever held in the West. Professor G. J. Brush, of New Haven, Connecticut, is President for the year, with Professor A. M. Mayer, of Hoboken, New Jersey, as Vice-President of Section A. The vice-presidency of Section B is vacant, in consequence of the resignation of Dr. Engelmann, who is in Europe. The chairmen of the sub-sections are: of Chemistry, W. R. Nichols, of Boston; of Microscopy, A. B. Hervey, of Taunton, Massachusetts; of Anthropology, Garrick Mallory, of Washington, D.C.; of Entomology, John G. Morris, of Baltimore, Maryland. The changes in the constitution of the Association which were proposed at the Boston meeting will be considered at this meeting. They are intended to enlarge the scope of the Association, and effect a reorganization of the sections, as follows: Section A, Physics; B, Astronomy and Pure Mathematics; C, Chemistry and its applications; D, Mechanical Science; E, Geology and Geography; F, Biology; G, Anthropology; H, Economic Science and Statistics; I, a permanent subsection of Microscopy. The contemplated excursions include one by the Anthropological Section to "Fort Ancient." A loan exhibition of scientific apparatus, appliances, and collections, will be held, in connection with the meeting, by the department of Science and Arts of the Ohio Mechanics' Institute.
The French Association at Algiers.—The French Association for the Advancement of Science met at Algiers, April 14th, and was attended by about fifteen hundred persons, among whom a large proportion of medical men was observed. The opening address was by the President, M. Chauveau, Professor of Physiology in the Lyons Veterinary College, and related principally to the germ theory and Pasteur's theory of fermentation. Several papers on local subjects, chiefly relating to the geology, geography, and demography of Algeria, were read in the general Association, among the results of the presentation of which were the diffusion of much information concerning the colony, and the acquisition of matter which will tend to help its development. One of the most interesting of these papers was by Colonel Playfair, the British consul-general, one of the only two Europeans who have visited their country, on the Kroumirs. Among the papers read in the sections, those in the medical and agronomical sections predominated over all the others. Most of the papers in the mathematical section related to subjects of pure geometry, and several of them were by foreign mathematicians. M. Trepied brought forward a project for the construction of an observatory at Algiers. The most important papers in the section of civil engineering were by Colonel Fourchault, on defensive villages, and by M. Trémaux, on irrigation. Accounts of the lead and iron mines of Tunis, and the copper-mines of the Petit Kabylie, were given in the geological section. Meteorology was well cared for with papers on the meteorology of Asia and of the Sahara, on meteorological instruments, and other related subjects. Among the anthropological papers, which were numerous, were those on the Kabyles, the Tziganes, the Romans in Africa, the Berber migration, the civil, political, and religious institutions of the Jews, and some craniological studies; a prehistoric map of the north of Africa was discussed in this section. The most interesting medical papers were on the epidemics of Algiers, acclimatization, and on the climate of Algiers as regards its influence on consumptive patients. A considerable proportion of the agronomical papers also bore on Algerian interests. Botany, zoölogy, and zoötechny were inadequately represented. The new section of pedagogy was established under the presidency of M. Godard, of the École Monge, in Paris. The working sessions of the Association were shortened in order to give time for the entertainments, some of which were peculiar to the country, and the excursions—to the borders of Tunis, to the country of the Kabyles, to the Sahara, to the boundaries of Morocco, and to interesting spots in the province. Each member of the meeting was presented with a work of scientific, historical, and economical notices of Algiers and Africa; and, whatever else the conference may have done, it has helped to add immensely to the world's knowledge of Northern Africa.
The association has now had a successful career of ten years, and has done some good work. The topics of which it takes cognizance are divided into the four groups of mathematical, physical and chemical, natural and economic sciences, and are considered in sixteen sections.
Hereditary Color-Blindness.—A correspondent has furnished us an account of some remarkable instances of hereditary color-blindness. "I recently heard," she writes, "a very intelligent boy of fourteen speak in this manner: 'Father, you know that green or brown mare of Abe's?' The same lad, speaking of a colored person—'What color?' interrupted a captious listener. 'About that color,' answered the boy, pointing to a jar of pickled cucumbers. The lad, whom I call D, belongs to a family who have for several generations been troubled with color-blindness. His grandfather was unable to distinguish red, green, and brown, and confounded blue and pink, but always named yellow aright." The same ancestor was once surprised by hearing some one speak of his father's sleigh as being green on the outside and red on the inside, for it had always appeared to him to be of the same color on both sides. He was also heard to remark that he could see no change in the color of the maple-leaves, which, as we all know, turn from their summer green to red, and then to brown. This form of color-blindness is particularly inconvenient to persons who wish to pick cherries or strawberries, for they have only the forms to guide them, without any help from the color. One of the brothers of the grandfather and two of his first-cousins had the same defect, and a nephew in the next generation. The youth spoken of in the beginning of this notice is the first in the present generation who has manifested it. Generally the affection appears to have been transmitted through the female line of the family, but to sons, and not to daughters. Exceptions to this rule are noticed in the case of a great-uncle of the youth's mother, who inherited it from his father and transmitted it to his four sons; and of a female relative, through whom it was transmitted to two daughters. By means of the instances related, the course of the affection is traced through five generations.
Why Prairies are Treeless.—Mr. Thomas Meehan believes that we have nearly reached the solution of the question of the cause of the absence of trees from the prairies. It is not climatic, for timber-belts flourish in all the prairie regions. It is not in conditions of soil, for the prairie soil is the most favorable to the germination of seeds, of trees as well as of other plants, and artificial plantations are remarkably successful wherever they are made. The real cause is probably to be found in the annual fires which have swept over the prairies from time immemorial, killing the young trees before they can grow large enough to resist the heat. The seeds of the annual plants of the prairie vegetation, maturing every year, are shed and find protection before the fires come; the young trees, on the, other hand, bear no seed, and can leave no resource for a succession after they are burned. This theory is supported by the fact that an abundant growth of trees has set in wherever the fires have been stopped. The fires were made by the aborigines for centuries before the white men came, possibly for the express purpose, Mr. Meehan suggests, of preventing the growth of trees and preserving the buffalo-pastures. The question remains how the prairies first came to be naked. They probably formed the bottoms of the lakes and marshes that were left after the retreat of the glaciers, and continued wet after the highlands were covered with trees. Man followed the glaciers so closely that he anticipated the trees on these spots, and, having learned already in southern latitudes the value of burnings, began them before the trees gained a foothold.
Darwin's Views on Vivisection.—The following is Mr. Darwin's reply to a letter from Professor Holmgren, of Upsala, requesting his views on the right to make experiments on living animals in the interest of science:
Down, Beckenham, April 14, 1881.
Dear Sir: In answer to your courteous letter of April 7th, I have no objection to express my opinion with respect to the right of experimenting on living animals. I use this latter expression as more correct and comprehensive than that of vivisection. You are at liberty to make any use of this letter which you may think fit, but if published I should wish the whole to appear. I have all my life been a strong advocate for humanity to animals, and have done what I could in my writings to enforce this duty. Several years ago, when the agitation against physiologists commenced in England, it was asserted that inhumanity was here practiced, and useless suffering caused to animals; and I was led to think that it might be advisable to have an act of Parliament on the subject. I then took an active part in trying to get a bill passed, such as would have removed all just cause of complaint, and at the same time have left physiologists free to pursue their researches—a bill very different from the act which has since been passed. It is right to add that the investigation of the matter by a Royal Commission proved that the accusations made against our English physiologists were false. From all that I have heard, however, I fear that in some parts of Europe little regard is paid to the sufferings of animals, and if Ibis be the case I should be glad to hear of legislation against inhumanity in any such country. On the other hand, I know that physiology can not possibly progress except by means of experiments on living animals, and I feel the deepest conviction that he who retards the progress of physiology commits a crime against mankind. Any one who remembers, as I can, the state of this science half a century ago, must admit that it has made immense progress, and it is now progressing at an ever-increasing rate.
What improvements in medical practice may be directly attributed to physiological research is a question which can be properly discussed only by those physiologists and medical practitioners who have studied the history of their subjects; but, as far as I can learn, the benefits are already great. However this may be, no one, unless he is grossly ignorant of what science has done for mankind, can entertain any doubt of the incalculable benefits which will hereafter be derived from physiology, not only by man, but by the lower animals. Look, for instance, at Pasteur's results in modifying the germs of the most malignant diseases, from which, as it so happens, animals will in the first place receive more relief than man. Let it be remembered how many lives and what a fearful amount of suffering have been saved by the knowledge gained of parasitic worms through the experiments of Virchow and others on living animals. In the future every one will be astonished at the ingratitude shown, at least in England, to these benefactors of mankind. As for myself, permit me to assure you that I honor, and shall always honor, every one who advances the noble science of physiology.
Dear sir, yours faithfully,
| Charles Darwin. |
| To Professor Holmgren. |
Tin in Australia and other Countries.—A German pamphlet by Dr. Eduard Reyer, on "Tin in Australia and Tasmania" (Vienna, 1880), gives some interesting facts relative to the production of tin in different countries outside of Europe. The mining of this metal has become an industry of considerable importance in the Australian colonies. The amount exported from Victoria to England rose from an average of about 130 tons a year between 1860 and 1869, to 2,500 tons in 1877; the production in New South Wales increased from 50 tons in 1872 to 7,000 tons in 1877. Four thousand tons were produced in Queensland in 1874; and the whole amount exported from Australia to England in the first five months of 1877, 1878, and 1879, was respectively 4,300, 4,100, and 2,900 tons. About 4,500 tons were produced in Tasmania in 1877; 4,100 were exported in the first five months of 1878, and 3,300 tons in the corresponding period of 1879. The ore occurs in Australia on the flanks of the mountains which run parallel to the eastern coast, in granite of the Devonian age, and has so far been got by washing from the sediment in the valleys. In Tasmania it is found in the quartz-porphyry of Mount Bischoff, and is likewise obtained by washing. Tin is found in several of the southwestern provinces of China, but it is not so largely produced in that country that considerable quantities arc not imported from abroad; it was formerly sent from Java to England; it was extensively mined in the province of Khorassan in Persia; is mentioned as having been formerly produced in Algeria; and is now produced in the Cape Colony at a rate represented by an exportation of about one hundred tons a year. It is found in small quantities or traces in. several places in the United States, as in Maine, New Hampshire, Connecticut, Pennsylvania, Virginia, North Carolina, Missouri, and California, and in parts of Mexico, but the whole production of North America is hardly worth speaking of. It is, however, a definite article of production and export in some South American states, as Peru, Chili, and Bolivia; it exists in the province of Minas Geraes in Brazil; and several abandoned tin-mines are mentioned in the Spanish West Indies.
The Glacial Ice-Sheet in the Interior States.—Professor N. H. Winchell suggests, in the "American Journal of Science," that the peculiar formation of ice, which Mr. Dall has described as occurring near Behring Strait (see "Popular Science Monthly" for May, page 130), presents features which may formerly have prevailed in our Western and Northwestern States. Both regions are alike free from high land and rocky hills suited for the production of a glacier. The proof that vast fields of glacier-ice formerly existed over our Northern interior States is now rarely questioned; "and it is highly probable," says Professor Winchell, "that the field explored by Mr. Dall is an epitome, under peculiar and somewhat inexplicable circumstances, of the vaster fields which extended from the Rocky Mountains on the West to the Alleghanies on the East, during the latest epoch of continental ice, the only important exception being that over the continent the southern termination of the ice-sheet was everywhere invisible, and abutted nowhere (in the interior) on the ocean-shore, so as to reveal its existence. The surface covering of the ice was the surface of the country, and, over many miles north from its actual termination, it supported a varied and even rank vegetation." Professor Winchell observes that the facts reported by Mr. Dall throw light on the manner of formation and deposit of the till, and on the origin of kames. The kames are gravel-ridges lying in till-covered countries, occupying the lower situations and generally bordered on either side by a parallel strip of swamp or low land. Now, if we suppose that the till before its deposit lay on the surface of the ice, it is plain that the surface drainage, gathering into streams, would produce deep channels in the ice-sheet, in the bottom of which would be gathered such stones and gravels as the stream could not carry away, and these would gradually sink deeper into the ice, perhaps to the rocky floor itself. When the ice had entirely disappeared, the bed of coarser matters thus formed "would lie undisturbed in its beautiful stratification, where the river produced it"; while on either side would be first the swampy or low land produced by the wash of the stream, and outside of this the unmodified till.
Undergrowth and Forest-Trees.—M. Gourmand has recently described some observations which he has made on the influence of thickets upon the decomposition of vegetable matter and the growth of large trees. A thicket may be formed in the course of eight or ten years after the undergrowth has started; as it rises in height we can at last distinguish between the atmosphere beneath it and the superior atmosphere to which the tops of the larger trees are exposed. Seventeen years of watching and periodical measuring of the growth of the trees of a tract bearing a deciduous undergrowth and a larger coniferous growth have shown that the rate of growth of the larger trees diminishes as the undergrowth becomes more dense; the only exceptions arc in glades where the undergrowth sends up vertical limbs instead of spreading out sidewise. The rate of growth thus appears to be modified according as the light is or is not able to penetrate the depth of the wood, and, as carbonic acid is in a corresponding degree more or less rapidly formed from the decomposition of the substances composing the humus. M. Gourmand concludes from these observations that light, when it reaches the ground after passing through foliage, stimulates the production of carbonic acid in decompositions that engender humus in proportion as that gas is decomposed by the green parts; that the growth of the larger trees is retarded, although their green parts stand out in full air and light, where the lower thicket cuts the light off too much from the soil and diminishes its reflex action on their tops; that this effect is governed largely by the arrangement of the limbs of the undergrowth, as it is less marked in glades, where they take a vertical direction; and that the humus under too dense an undergrowth loses a part of its efficiency, and presents an analogy with barn-yard manure, which will remain inert for several years if it is buried too deeply.
The Weather, and Summer Diarrhœas.—Mr. G. B. Longstaff has recently pointed out, in an address before the Society of Medical Officers of Health, some facts concerning the prevalence of summer diarrhœa in England, which are not fully accounted for by the prevailing theories of its origin. He distinguishes between two kinds of diarrhœa: one general, prevailing throughout the year, affecting persons at all ages, and nearly evenly distributed in town and country; and a specific form, which prevails in the summer months and affects most persons at the extremes of life, particularly infants of less than two years old, and which is not definitely modified by changes of season. The second form is, as a rule, a disease of towns, but different towns are differently affected by it. The summer of 1880 was a warm one in England, with the mean temperature in August and September above the average, and a high rainfall in July and September, while little rain fell in August; the death-rate from diarrhœa in England and Wales exceeded the average of the previous ten years by nearly fifty per cent. The comparison of the mortality from this cause in different towns, as between the towns and with the general mortality of the kingdom, failed to establish such a connection between the changes of temperature and hygrometric conditions and the prevalence of the disease as would be required under the theory that high temperature and drought are primary causes of its production. Out of eleven towns in which the meteorological conditions were recorded, mean temperatures of 60° and upward occurred in June in seven, but in no case was the heat at that time accompanied or immediately followed by numerous deaths from diarrhoea. In nine out of the eleven towns, the highest mean temperature was registered in the first week in September. The epidemic had reached its highest point before that week in four of them. The hot weather continued much longer in London than in Nottingham, yet Nottingham suffered sixty per cent, more severely from diarrhoea than London. The death-rate in Brighton during the last week in July was double that of any other great town for the same week; and "it is a remarkable fact that, although August was hotter and more free from rain than July in London and Brighton, in both towns deaths from diarrhoea diminished in frequency as the month approached its end," Thus, neither the incidence of the disease from week to week nor its distribution in different parts of the country can be explained by meteorological conditions alone; and it is evident that other factors must be taken into account. The events of 1880 as reviewed by him are regarded by Mr. Longstaff as confirmatory, so far as they go, of the theory that the exciting cause of diarrhœa is an organism or some other concomitant of the decomposition of organic matter, which can only exist, or become virulent in its properties, after prolonged high temperature. The fact that lassitude and exhaustion are produced as predisposing conditions to the disease by high temperatures in the early part of the summer does not contradict this theory, but agrees with it fully.
Papuan Women and Feasts.—The taboo is in full force in New Guinea, particularly in the restrictions which it imposes on the action of women. They are forbidden to enter the buambramra, are excluded from all the feasts, and every dainty which they prepare for the feasts, especially the keu, or principal drink, is forbidden to them and to the children. They must not go near the meeting-place of the men, and must instantly flee whenever they hear the sound of music. The only answer given for this exclusion is that, if it were not enforced, the women and children would fall ill and die. The musical instruments of the Papuans are pipes or horns of bamboo, cocoanut-shell, or a peculiar root, which are used to reënforce the voice, a kind of a rattle, and a rude drum. Their feasts are prepared with considerable ceremony, but without noise or confusion, and in a way that shows a remarkable appreciation of the division of labor. Important constituents of the feast are the two favorite drinks, the munki-la, which is prepared from the cocoanut, and the keu, an extract from the chewed leaves of a plant of the genus Piper. The musical instruments are played during the whole feast, as an infallible means of keeping the women and children from disturbing the guests. After all is over, the lower jaw of the pig or dog which has constituted the principal dish is hung up in the buambramra as a memento. The keu has soporific qualities, and the friends of a Papuan who has taken too much of it are accustomed, in order to keep him awake, to tickle with a stalk of grass the cornea and conjunctiva of his eyes till they become full of tears, and he declares that he no longer feels sleepy. This operation is considered a very pleasant one.
Woman as a Sanitary Reformer.—Dr. B. W. Richardson declares that woman can pursue no nobler occupation than that of attending to the care of health and the prevention of disease within the domestic sphere. This is peculiarly a calling of woman, not only because it agrees with her character and tastes, but also because she is at home and in a position to give it constant attention, while the man is abroad and engaged with other business. The training required for the proper performance of this function is really very simple. A woman can master physiology so far as to understand the general construction of the human body; she can make herself acquainted with its nine great systems, can be taught to comprehend the leading facts bearing on the anatomy and physiology of those systems, and to understand what part food plays in the economy, the relationships and effects of particular foods, and their relative adaptation to different ages and conditions of the body. Woman should also be acquainted with the construction and operation of the heart and the lungs. Were women trained in the knowledge of elementary truths about the visual function and guided by them, they would see that their children did not assume those positions in study that conduce to short-sightedness and curved spines; if they carefully studied the nature and functions of the skin, they would learn to insist upon the necessity of daily purification by the bath. Woman might also, and ought to, learn all that health requires in the construction and maintenance of the house: to maintain economically within it an equable temperature at all seasons; to keep the air free from dust; to know all about and watch all the drain-pipes, and see that they are kept as systematically clean as the china; to distinguish whether the water is wholesome and agreeable with as much facility as she determines whether the looking-glass is clear; to superintend the purification of the water; and to see that sunlight finds its way into every apartment, and that damp has no place in any one of her rooms. She ought to study the nature and uses of foods, so as to be able not only to make the best selections and carry out the best modes of preparation, but even to introduce new and improved modes of cooking. The knowledge of the diagnosis of disease is not necessary for women except in a limited degree, but they ought to know the correct names and characters of common diseases, to be acquainted with the facts relating to the periods of incubation of those diseases, and to have the best methods of preventing disease at their fingers' ends.
Sound-Signals.—Mr. E. Price-Edwards recently delivered before the Society of Arts a valuable lecture on "Signaling by Means of Sound," in which he considered the requisites of a good signal, and discussed the merits of the different signals in use. The essential quality of a good sound signal is that it shall give a strong sound which can be uniformly heard at a definite distance. The range of a sound is determined by the force with which it is uttered, and is modified by certain conditions of the atmosphere. It is also controlled in part by its musical pitch. The most effective sounds are not found among the very highest pitches, as many imagine, any more than among the very low ones, but appear to lie among the intermediate pitches, to which the ear is best adapted. Bells have been long in use to give signals, but their sounds are curiously fluctuating, and it is not probable that the vibrations from the largest bell are of sufficient intensity to yield a sound capable of overcoming opposing influences, even of a slight nature. Gongs give a distinctive sound, serviceable at a short distance, but it, too, is soon dissipated after leaving the vicinity of the instrument. Gun-signals are of great value, but, according to Professor Tyndall, they can not always be depended upon to overcome local or temporary obstacles to the propagation of sound. It is, moreover, not always convenient to place and manage guns where it is desirable to use them, or to fire them as rapidly as repetition of sound is wanted. Mr. J. R. Wigham, of Dublin, has invented a gas-gun, which can be loaded and fired at a considerable distance from the point of explosion. It consists of a tube of the desired size placed at the point where the signal is to be made, and connected with a gas-main or gas-holder by iron piping. The gun is loaded with an explosive mixture of gas and atmospheric air, fire is applied at the short end of the tube, and the explosion takes place at the mouth of the gun almost immediately. An exceedingly sudden and sharp blow is given to the air, and a sound-wave of great initial intensity is generated by the explosion of gun-cotton. The apparatus employed to explode that substance in the ordinary way is, however, cumbrous, and can not be used conveniently where speedy manipulation is wanted. A rocket has been devised to carry a charge of gun-cotton, or tonite, to a certain height, where it is caused to explode, which has been tested with the most satisfactory effects; from the height of six hundred feet, to which the rocket may be adapted, a direct sound is sent downward into places which would be completely hidden from the level at which a gun could be fired, and which would seldom be reached by the sound of its discharge. A kind of cartridge of tonite has been made, to be sent high up into the air, explode there, and scatter a shower of brilliant stars, and has been adopted for the purpose of making signals on many vessels. Mr. Price-Edwards does not express a high opinion of whistles; but one of Mr. Courtenay's automatic buoy-whistles has been used off the Goodwin Sands with success, and two others are to be placed off the English coast. The palm of superiority in all respects, as a signal, is accorded to the American siren. Among the improvements that have been made in it are one for increasing the suddenness and intensity of the sound, adaptations for use on ships and steamers, and the double siren, in which two notes are produced simultaneously, the power of the instrument is more than doubled, and a characteristic feature is given to the sound.
The Mékarski Air-Engine.—The Mékarski air-engine, which has been employed satisfactorily for several months on the tramways of Nantes, France, is being introduced into England by the Compressed Air Engines Company. Both engines combined with the car and simple traction-engines are used at Nantes. In the combined cars and engines, ten cylindrical steel reservoirs for the compressed air are placed beneath the floor, seven of which are united into one system, called the "battery," and the remaining three are united into a second system called the "reserve." Both the battery and the reserve are charged at the principal station with air compressed to thirty atmospheres. The cylinders are placed horizontally in front of the driving-wheels, and are five and three eighths inches in diameter, by ten and a quarter inches stroke. In front of the car, and on the driver's platform, is a small reservoir, which is charged with water, for about two thirds of its capacity, at a temperature of 320°. The air, in passing from the battery or from the reserve to the engines, traverses the water in this reservoir, and thus becomes heated before reaching the cylinders. After doing its work in the cylinders, it passes into a box, from which it escapes into the air. Under this arrangement, which is peculiar to the Mékarski engine, a smaller quantity of air is needed, and the danger of ice forming in the exhaust passages of the cylinder is obviated. A regulating valve on the top of the hot-water reservoir serves to keep the air from the reservoirs at a uniform pressure, whatever may be the variations in the demand by the engines. The combined car, when ready for work, weighs six tons. The traction-engines draw two cars each. The charge of air carried is enough for the whole "round trip."
Stone-Age Civilization in New Guinea.—The Papuans of the Maclay coast, New Guinea, afford a fine and instructive specimen of a living race still in the stone age. The implements on which they have expended their artistic skill come under the two categories of fragments of flint, shells, and bones, and chipped stones in the form of axes. The ornaments upon them are classified by Mr. J. C. Galton, in a notice of M. Maclay's observations, into ornaments made solely for a decorative purpose, ornaments and drawings demonstrating the first beginning of the figurative or ideal style of writing, and ornaments, sketches, and carvings, which stand in close relation to the superstitions and dark religious ideas of the Papuans. The salient character of the ornaments is that they are generally rectilinear, and this is because the bamboo and reed, on which ornamentation was first attempted, do not conveniently admit of any other style of drawing. The style thus fixed on wood was readily transferred to other substances on which decoration was attempted. That the want of variety in subjects of decoration does not proceed from lack of inventive power and skill is shown by the fact that as soon as some of the men got improved tools, such as bits of glass bottles, they introduced refinements and variations into their wood ornamentation. The Papuans have been supposed to be destitute of any art of writing, but M. Maclay believes that he has found evidence of the use by them of an ideograph in a very rude form. He observed rude figures painted in different places in various combinations, the purpose of which puzzled him for a long time, till it was revealed at a feast which was held on the occasion of the launching of some canoes, on which the natives had been working for a long time. One of the party, during the feast, drew a number of figures resembling those M. Maclay had seen, and evidently referring to the work in hand. The two boats were represented as they were, half on land and half in water; then followed representations of men carrying pigs, the "covers" of the feast, M. Maclay's canoe with its flag, and the canoes of the visiting guests. Further evidence has made it tolerably clear that such representations are real ideographs. The carvings on wood, to which a religious bearing is ascribed, seem to show a regular progress toward sculpture, by the transformation of simple decorations into bas-relief, then into alto rilievo, and finally into the complete figure.
Plant-Migrations.—An interesting monograph has been published at the University of Giessen, Germany, on the migrations of two plants, the Puccinea malvacearum, or mallows fungus, and the Elodea Canadensis (Anacharis Canadensis, Gray). The former plant was first noticed infesting the mallows-plants of Chili. It was observed in Spain, for the first time in Europe, in 1869, having, it is thought, been introduced in the course of trade. Next it was found in France, infesting some ten species of the mallows family, in 1872, 1873, and 1874; it appeared in England in 1873, and was carried to Holland and Belgium in 1874. It was also found at the Cape of Good Hope and in Australia in 1874. It began to attract attention in Germany and Italy in 1874, and appears now to be diffused all over Europe, as its presence is mentioned in Bohemia and Hungary and at Athens, which appears so far to mark its southeastern point of extension. The Elodea, or Anacharis Canadensis, was noticed in single localities in Ireland in 1836 and 1842. Toward 1850 it became quite abundant, and in the course of the next ten years found its way to the Botanical Gardens of Utrecht and the swamps in the neighborhood of Ghent. It was growing in several places in France in 1866. It is now found in considerable abundance in the lower Rhine, the Elbe and its branches, the Havel and Spree, and the Oder. It has extended from Corrib, Ireland, on the west, and Grenoble, France, on the south, to Riga, on the northeast. It has been carried by sprouts to all the places where it grows; for only female plants (not a single male plant) are to be found in all Europe.
Efficiency of Present Causes in Geological Action.—M. Stanislas Meunier has recently published a work discussing the sufficiency of the causes which are still in operation to account for the production of the geological phenomena of the past. Illustrations of the principle involved in the discussion may easily be found in examining some of the formations near the surface. In the section of the coal-beds of Valenciennes, thick, horizontal cretaceous beds appear, resting on carboniferous beds, the strata of which are contorted, bent, and folded neither more nor less than the strata of which the highest mountain-chains are composed. As the contact of the chalk and the coal is horizontal, it must be admitted that, previous to the deposit of the secondary rocks, the ground, which had been greatly disturbed by the foldings of the carboniferous strata, had been again planed down to a level. The first thought would be to attribute the planing down to some sudden and violent action carrying away all of the missing matter at once. The view is entirely changed when we remark that quite as important denudations are taking place now in populous districts without any perturbations of a violent character. Thus, on the British coast of the English Channel the sea is gaining about a yard a year upon the land, and the fact is recognized in sales. The result of this denudation, which is taking place so gradually, can not be distinguished from that of a sudden razing of the strata at the bottom of the sea. M. Meunier examines likewise the theory that river-valleys have been formed by the action of streams in a period of floods, when they were many times larger than the present rivers. The valleys of the rivers, he believes, correspond with original fractures of the soil; this once accepted, we may admit that the stream was neither much more voluminous nor much more rapid in quaternary times than at present. In the course of an indeterminate period of time it has widened its valley by the operation of the sinuosity of its meanderings, and has covered the whole surface of the soil with detritus. The production of gravel terraces may be attributed to slight, elevations of the soil; and many supposed bowlders of considerable dimensions may have been formed by the weathering away of angular blocks. The disappearance of species is now regarded as simply the natural result of the competition of other species; and evidence is not wholly wanting that the introduction of new species is still going on. Thus, a little lizard has been observed quartered on a rock near the Island of Capri which is manifestly derived from a quite different lizard living in the island itself.