Popular Science Monthly/Volume 19/July 1881/Popular Miscellany
| ←Literary Notices | Popular Science Monthly Volume 19 July 1881 (1881) Popular Miscellany |
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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, POPULAR MISCELLANY.
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��cal Science; E, Geology and Geography; F, Biology ; G, Anthropology ; H, Economic Science and Statistics ; I, a permanent sub- section of Microscopy. The contemplated excursions include one by the Anthropologi- cal Section to "Fort Ancient." A loan ex- hibition 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' In- stitute.
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, Pro- fessor of Physiology in the Lyons Veteri- nary College, and related principally to the germ theory and Pasteur's theory of fer- mentation. 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 in- teresting 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 pre- dominated 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 Al- giers. The most important papers in the section of civil engineering were by Colonel Fourchault, on defensive villages, and by M. Tremaux, on irrigation. Accounts of the lead and iron mines of Tunis, and the cop- per-mines of the Petit Kabylie, were given in the geological section. Meteorology was well cared for with papers on the meteo- rology of Asia and of the Sahara, on meteor- ological instruments, and other related sub- jects. Among the anthropological papers, which were numerous, were those on the
��Kabyles, the Tziganes, the Romans in Af- rica, the Berber migration, the civil, politi- cal, and religious institutions of the Jews, and some craniological studies; a prehis- toric map of the north of Africa was dis- cussed in this section. The most interest- ing medical papers were on the epidemics of Algiers, acclimatization, and on the cli- mate of Algiers as regards its influence on consumptive patients. A considerable pro- portion of the agronomical papers also bore on Algerian interests. Botany, zoology, and zootechny were inadequately represented. The new section of pedagogy was estab- lished under the presidency of M. Godard, of the Ecole Monge, in Paris. The working sessions of the Association were shortened in order to give time for the entertain- ments, 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 Xorthern Africa.
The association has now had a success- ful 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 con- sidered in sixteen sections.
Hereditary Color-Blindness. A corre- spondent 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 lis- tener. '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 grand- father was unable to distinguish red, green, and brown, and confounded blue and pink, but always named yellow aright." The
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��same ancestor was once surprised by hear- ing 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 sum- mer green to red, and then to brown. This form of color-blindness is particularly in- convenient to pei'sons who wish to pick cherries or stra\i'berries, 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 ccreat-uncle of the vouth's mother, who inherited it from his father and trans- mitted it to his four sons ; and of a fe- male relative, through whom it was trans- mitted to two daughters. By means of the instances related, the course of the af- fection 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 condi- tions of soil, for the prairie soil is the most favorable to the germination of seeds, of trees as well as of other plants, and arti- ficial 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, pos- sibly 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 cov- ered with trees. Man followed the glaciers so closely that he anticipated the trees on these spots, and, having learned already in southei^n latitudes the value of burnings, began them before the trees gained a foot- hold.
Darwin's Views on Vivisection. The
following is Mr. Darwin's reply to a letter from Professor Holmgren, of Upsala, re- questing his views on the right to make experiments on living animals in the interest of science:
Down, Beckenham, April 14, 1881. Deak Sir : In answer to your courteous let- ter of April 7tli, I have no objection to express my opinion with respect to the right of experi- menting 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 advo- cate 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 prac- ticed, and useless suffL-ring 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 diflFerent from the act which has since been passed. It is right to add that the investigation of the matter by a RojmI Commis- sion proved that the accusations made ngainst our English physiologists were false. From all that I have heard, liovvever, I fear that in some parts of Europe little regard is paid to the suf- ferings of animals, and if Ibis be the case I should be glad to hear of legislation against in- humanity 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
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��who remembers, as I can, the state of this sci- ence half a century ago, must admit that it lias made immense progress, and it is now progress- ing at an ever-iucreasing rate.
What improvements in medical practice may be directly attributed to physiological re- search is a question which can be properly dis- cussed 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 suflfering have been saved by the knowledge gained of parasitic worms through the experiments of Virchow and others on liv- ing animals. In the future every one will be astonished at the ingratitude shown, at least in England, to these benefjictors 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 Anstralia and other Conntries.
A German pamphlet by Dr. Eduard Reyer, on " Tin in Australia and Tasmania " (Vi- enna, 1880), gives some interesting facts rel- ative 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 Vic- toria to England rose from an average of about 130 tons a year between 1860 and 1869, to 2,500 tons in 18*77 ; the produc- tion in Xew 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 re- spectively 4,300, 4,100, and 2,900 tons. About 4,500 tons were produced in Tasma- nia 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 wash- ing. Tin is found in several of the south- western provinces of China, but it is not so largely produced in that country that con- siderable 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 men- tioned as having been formerly produced in Algeria; and is now produced in the Cape Colony at a rate represented by an ex- portation 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, Penn- sylvania, Virginia, Xorth 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.
Tlie Glacial Ice-Sheet in the Interior States. Professor N. H. Winchell sug- gests, in the " American Journal of Sci- ence," 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 pre- vailed 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 prob- able," says Professor Winchell, "that the field explored by Mr. Dall is an epitome, under peculiar and somewhat inexplicable circumstances, of the vaster fields which ex- tended from the Rocky Mountains on the West to the Alleghanies on the East, dur- ing 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
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��ocean-shore, so as to reveal its existence. The surface covering of the ice was the sur- face of the country, and, over many miles north from its actual termination, it sup- ported a varied and even rank vegetation." Professor Winchell observes that the facts reported by Mr. Dall throw light on the mamier of formation and deposit of the till, and on the origin of Jcames. The kames are gravel-ridges lying in till-covcred coun- tries, occupying the lower situations and generally bordered on either side by a paral- lel 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 ei- ther side would be first the swampy or low land produced by the wash of the stream, and outside of this the unmodified till.
UndtTgrowth and Forest - Trees. M.
Gourmand has recently described some ob- servations which he has made on the influ- ence 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 under- growth has started ; as it rises in height we can at last distinguish between the atmos- phere beneath it and the superior atmos- phere 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 un- dergrowth 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 side- wise. 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 com- posing the humus. M. Gourmand concludes from these observations that light, when it reaches the gi'ound after passing through foliage, stimulates the production of carbonic acid in decompositions that engender hu- mus in proportion as that gas is decom- posed 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 ef- fect 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 un- der 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 Diarrhoeas.
Mr. G. B. Longstaff has recently pointed out, in an address before the Society of Medi- cal Officers of Ilealth, some facts concerning the prevalence of summer diarrhoea in Eng- land, which are not fully accounted for by the prevailing theories of its origin. lie distinguishes between two kinds of diar- rhoea: one general, prevailing throughout the year, affecting persons at all ages, and nearly evenly distributed in town and coun- try; and a specific form, which prevails in the summer months and affects most per- sons at the extremes of life, particularly in- fants 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 diarrhoea 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 be- tween the towns and with the general mor- tality of the kingdom, failed to establish
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��sucli a connection between tlie changes of temperature and hygrometric conditions and the prevalence of the disease as would be required under the theory that high tempera- ture 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 oc- curred 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 Xottingham, yet Nottingham suf- fered 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 diar- rhoea diminished in frequency as the month approached its end," Thus, neither the in- cidence 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 ex- citing cause of diarrhoea is an organism or some other concomitant of the decomposi- tion 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 ta- boo is in full force in New Guinea, particu- larly in the restrictions which it imposes on the action of women. They are forbid- den to enter the huamhramra, are exclud- ed from all the feasts, and every dainty which they prepare for the feasts, especially
��the Tceu^ 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 Papu- ans are pipes or horns of bamboo, cocoa- nut-shell, or a peculiar root, which are used to reenforce the voice, a kind of a rattle, and a rude drum. Their feasts are pre- pared with considerable ceremony, but with- out noise or confusion, and in a way that shows a remarkable appreciation of the di- vision of labor. Important constituents of the feast are the two favorite drinks, the munki-la, which is prepared from the cocoa- nut, 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 dis- turbing the guests. After all is over, the lower jaw of the pig or dog which has con- stituted the principal dish is hung up in the hxuunhramra as a memento. The kcu 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 con- sidered a very pleasant one.
Woman as a Sanitary Reformer. Dr.
B. W. Hichardson 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 wom- an, not only because it agrees with her character and tastes, but also because she is at home and in a position to give it con- stant 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 under- stand 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
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��the anatomy and physiology of those sys- tems, and to tinderstand 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 ac- quainted with the construction and opera- tion of the heart and the lungs. Were women trained in the knowledge of element- ary 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 tliat 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 look- ing-glass is clear ; to superintend the puri- fication of the water ; and to see that sun- light 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 cook- ing. 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 re- lating to the periods of incubation of those diseases, and to have the best methods of preventing disease at their fingers' ends.
Sound-Signals. Mv. E. Price-Edwards recently delivered before the Society of Arts a valua'ole lecture on "Signaling by Means of Sound," in which he considered the requi- sites 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 modi- fied 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 w"hich the ear is best adapted. Bells have been long in use to give signals, but their sounds are curious- ly fluctuating, and it is not probable that the vibrations from the largest bell are of suflScient 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 ob- stacles 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 repe- tition of sound is wanted. Mr. J . R. Wig- ham, of Dublin, has invented a gas-gun, which can be loaded and fired at a consider- able 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 load- ed with an explosive mixture of gas and at- mospheric air, fire is applied at the short end of the tube, and the explosion takes place at the mouth of the gun almost imme- diately. 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 em- ployed to explode that substance in the or- dinary way is, however, cumbrous, and can not be used conveniently where speedy ma- nipulation 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 down- ward into places which would be com- pletely hidden from the level at which a
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��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 pur- pose of making signals on many vessels. Mr. Price-Edwards does not express a high opinion of whistles ; but one of Mr. Courte- nay'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 re- spects, as a signal, is accorded to the Ameri- can 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 Mekarski Air-Engine. The Me-
karski air-engine, which has been employed satisfactorily for several months on the tramways of Nantes, France, is being intro- duced 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 re- maining three are united into a second sys- tem called the " reserve." Both the bat- tery and the reserve are charged at the prin- cipal station with air compressed to thii'ty atmospheres. The cylinders are placed hori- zontally in front of the driving-wheels, and are five and three eighths inches in diam- eter, by ten and a quarter inches stroke. In front of the car, and on the driver's plat- form, is a small reservoir, which is charged with water, for about two thirds of its ca- pacity, 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 Mekarski engine, a smaller quantity of air is needed, and the danger of ice forming in the exhaust passages of the cyl- inder is obviated. A regxxlating valve on the top of the hot-water reservoir serves to keep the air from the reservoirs at a uni- form pressure, whatever may be the varia- tions 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 CiYilization in New Gninea.
The Papuans of the Maclay coast, New Guinea, afford a fine and instructive speci- men of a living race still in the stone age. The implements on which they have ex- pended 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, orna- ments and drawings demonstrating the first beginning of the figurative or ideal style of writing, and ornaments, sketches, and carv- ings, which stand in close relation to the su- perstitions and dark religious ideas of the Papuans. The salient character of the orna- ments is that they are generally rectilin- ear, and this is because the bamboo and reed, on which ornamentation was first at- tempted, 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 at- tempted. That the want of variety in sub- jects 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 ornamenta- tion. 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 com- binations, 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
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��THE POPULAR SCIEXCE MONTHLY
��launching of some canoes, on which the na- tives had been working for a long time. One of the party, during the feast, drew a number of figures resembling those M. Ma- clay 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 transfor- mation of simple decorations into bas-relief, then into alio rilievo^ and finally into the complete figure.
Plant-Migrations. -An interesting mon- ograph has been published at the Univer- sity of Giessen, Germany, on the migra- tions of two plants, the Puccinea malvacea- riim, or mallows fungus, and the- Elodea Canadensis {Anacharis Canadensis^ Gray). The former plant was first noticed infest- ing the mallows-plants of Chili. It was ob- served in Spain, for the first time in Europe, in 1869, having, it is thought, been intro- duced 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 dif- fused 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 Elo- dea^ or Anacharis Canadensis, was noticed in single localities in Ireland in 1836 and 1842. Toward 1850 it became quite abun- dant, and in the course of the next ten years found its way to the Botanical Gar- dens 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 ex-
��tended 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 Geologi- cal Action. M. Stanislas Meunier has re- cently published a work discussing the suf- ficiency of the causes which are still in operation to account for the production of the geological phenomena of the past. Il- lustrations of the principle involved in the discussion may easily be found in examin- ing some of the formations near the sur- face. 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 second- ary 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 carrymg 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 per- turbations 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 tak- ing place so gradually, can not be distin- guished from that of a sudden razing of the strata at the bottom of the sea. M. Meunicr examines likewise the theory that river-val- leys 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 be- lieves, correspond with original fractures of the soil ; this once accepted, we may admit that the stream was neither much more vo- luminous 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.
