Popular Science Monthly/Volume 18/November 1880/Popular Miscellany
Improved Safety Construction of Elevators.—With an appliance in such general use as the elevator, means of securing safety in case of the parting of the cable, or failure of other parts of the moving apparatus, are of prime importance. A great variety of devices, many of them quite ingenious, have been designed to accomplish this object, but few of them are entirely satisfactory. They have done much to decrease accidents, but these still happen frequently enough with them to show the necessity of a more perfect apparatus. These mechanical stops consist of combinations of levers, pawls, and clutches so arranged that the weight of the carriage will throw them into action. Both classes, those which bring the carriage to a sudden stop, and those which act as a break, need to begin to act the moment the fall commences, or the motion becomes so great as to be beyond control. From various causes impossible to provide against, these devices frequently fail at the critical moment, causing loss of life or damage to property. Recently a system of protection has been perfected and is now being introduced, which, the promoters claim, secures perfect safety, and the trials made in this and other cities seem to amply confirm the claim. It consists in making the descending carriage act as a plunger to compress the air in the shaft below it, so as to form a cushion which retards and gradually overcomes its motion. The change in the ordinary construction of the elevator to secure this action is very slight, and can readily be applied to one already put up. The shaft is made to fit the elevator carriage closely, through the first three or four feet of the lower portion, and then gradually widens to the full size. This funnel-shaped portion extends from fifteen to twenty feet above the contracted base, depending upon the size and height of the elevator. A stiff rubber flange around the lower edge of the carriage leaves a space for the escape of the air in the contracted portion of not more than one fourth of an inch wide. The straight part of the shaft above the funnel is of a size to leave a space of six to eight inches all around the carriage. With such a constructed shaft, the carriage, when it begins to fall, readily presses the air from beneath it up the sides of the shaft. As it gains in velocity, greater resistance is offered by the air, and, as it descends through the funnel portion, this is rapidly increased by the narrowing of the air outlet. When the contracted base portion is reached, the confined air has only a narrow outlet, and the resistance it offers is consequently very great. The air arrests the motion of the carriage so gradually that there is very little shock. In one of the trials in this city where the fall was seventy-five feet, eggs and delicate glassware placed on the floor of the car were unbroken. A great number of trials have been made, and many persons have gone down in the falling cars without injury. With the shaft properly and strongly built in the lower portion where the strain comes, this apparatus seems to offer no chance of failure.
Types of Pottery.—Professor E. S. Morse read an interesting paper on this subject at the last meeting of the American Association. The earlier types belonging to the shell-heaps of Japan were described and illustrated by specimens from each of the deposits examined by Mr. Morse and his special students. The pottery of Yezo was nearly all cord-marked, while the shell-heap pottery of the middle of Japan had a much less proportion cord-marked. In the southern portions of Japan, at Higo, cord-marked pottery was extremely rare. He remarked on the extreme diversity in the shape and ornamentation of the pottery in different places in Japan—the pottery of Yezo resembling the pottery of the northern United States, and the pottery from the central portions of Japan resembling that found in Porto Rico and Jamaica. He also spoke of the hard, blue pottery supposed to be Corean, and associated with it a red pottery which might have been made by the same people. This was lathe-turned. Other forms were mentioned and illustrated by examples.
The Fiftieth Meeting of the British Association.—No remarkable discoveries were brought forward at the recent meeting of the British Association for the Advancement of Science, but the addresses and papers in the various sections showed a steady advance in scientific work. Professor A. C. Ramsay, the new President, chose for the subject of his inaugural address the doctrine of uniformity, under the title of "The Recurrence of Certain Phenomena in Geological Time." There has recently been a disposition in certain quarters to question the truth of the doctrine in the extended application made by most geologists. The questioners admit that geologic changes in times past were produced by the same forces now in operation, but deny that they were of the same degree. The uniformity and cataclysmic theories seem to them to both contain truth. Professor Ramsay reaffirms the uniformity doctrine in the broadest and most general manner, and very ably defends his position. One of the most valuable if not the most important address of the meeting was that of Professor W. G. Adams, before the Section of Mathematics and Physics, reviewing recent work in the domain of molecular physics. His statement of the molecular condition of the three forms of matter—solid, liquid, and gaseous—was the clearest and least technical that has been made. He reviewed the work done by Lockyer and others in spectrum analysis, and, without committing himself to the conclusions drawn from them by the several workers, pointed out that the advance in our knowledge of molecular action is in the direction of effacing the distinction between chemistry and physics. It seemed to him even that all the sciences were becoming more and more branches of physics—that they "are yielding results of vast importance when the methods and established principles of physics are applied to them." Professor Adams closed his address with a consideration of the influence of the sun in producing magnetic diurnal variations. A number of reports were submitted in this section, the most important of which was that on the present state of spectrum analysis. It gave an account of recent progress both in the methods and results, together with an extended list of everything that had been published on the subject in the past few years. Papers were contributed by Mr. Preece, on the proper form of lightning-conductors, and by Mr. Richard Anderson, on the necessity of inspection of them. Dr. Tempest Anderson described an improved heliograph and an apparatus for estimating astigmatism. A powerful magnet for magneto-machines was described by Mr. Ladd, and a new form of electro-motor by Mr. Weisendanger. In the Chemical Section Dr. J. H. Gilbert gave an able summary of the state of agricultural chemistry, with an account of his own researches during a number of years, and criticism of various methods of applying chemistry to agriculture that have found advocates. The report upon the best means of obtaining light from coal-gas was the one in this section of the greatest interest to the public. It concludes that improved light must be sought in the use of more perfect burners, and that the best, fitted with , now made by Sugg, Peebles, and others, answer all practical purposes. In the Biological section, the principal feature was the address of the Vice-President, F. W. Balfour, before the Department of Anatomy and Physiology. He sketched briefly the progress recently made in embryology by applying the laws of variation and heredity. He contends that the evidence now in favor of the development theory is overwhelming, and there are very few naturalists who do not accept it in its main features. Dr. Sorby's address before the Geological Section was an important discussion of the structure of volcanic rocks and artificial slags, showing that a study of the process of formation of the latter throws much light upon that of the former. Professor Prestwich here took exception to the conclusions of Professor Ramsay's address regarding unvarying uniformity, contending that the superficial deposit termed "trail," "warp," and "head," in the southwest of Europe showed that this part had been submerged in recent geological times. Other papers of interest and value were those by G. M. Dawson on the "Geology of British Columbia," by Dr. Phené; on the geology of the Balearic Islands; and by Mr. W. T. Blanford on the age and relations of the Pikermi and Sewalik faunas in India. Sir J. H. Lefroy, in the Geographical Section, devoted his address to the advances made in geographical research in North America, showing that the great increase of our knowledge of this region is due to railways and the various State surveys. Among the interesting facts mentioned are the rise in the level of some American lakes, and the depths to which the ground is permanently frozen in the northern part of British North America. Though, before 1866, the surface of Salt Lake had been falling, since that time it has risen eleven feet. Pyramid Lake has risen nine feet, and Lake Winnemucca twenty-two feet. No theory of the cause was advanced. The ground at Fort Norman, on the Mackenzie River, is frozen to a depth of forty-five feet, and at York Factory, on Hudson Bay, but twenty-three feet, while at Yakutsk, Siberia, it is frozen to a depth of three hundred and eighty feet! Quite a number of papers were read in this section, showing a large and rapid increase of geographical knowledge. The most important of the public lectures was that by Mr. Francis Galton, on "Mental Imagery," which is published in the present number of the "Monthly." Professor Boyd Dawkins delivered an address on "Primeval Man," which was mainly a summary of the matter of his recent work. An account of "Professor Expedition" was given by Mr. F. Seebohm to an audience of workingmen.
The Westinghouse Automatic Brake.—The well-known Westinghouse air-brake, invented and so largely used in this country, seems to be rapidly gaining in favor abroad. The English journal "Iron," in a recent issue, highly commends it as answering all the requirements of a perfect brake, as laid down by the Board of Trade, and gives some valuable statistics concerning its use. From returns received up to the 20th of last July, it appears that the number of applications of the automatic brake throughout the world is—to engines, 3,277, and to carriages, 13,502. This is an increase in less than fourteen months of 1,594 to engines, and 6,255 to carriages. Besides this, there are 2,472 engines and 8,812 carriages fitted with the nonautomatic brake—that is, the one using ordinary air-pressure. This, then, makes a total of 5,749 engines and 22,314 carriages fitted with this apparatus. In the case of 678 engines and 2,720 cars a change has been made from the non-automatic to the automatic. This equipment is divided between the different countries as follows: The United States has 2,211 engines and 7,224 cars using it; England 456 engines and 2,942 carriages; in France there are but 203 engines and 1,609 carriages; and in Belgium 197 of the former and 1,241 of the latter. The number in use in Germany, Russia, and Holland is small, ranging from 55 to 28 engines and 93 to 117 carriage equipments. A few are also in use in Italy, Sweden, and the British provinces. Certain very excellent improvements and additions "Iron" points out have recently been made to this brake system, which greatly increase its usefulness. There are a method of lighting the cars and a means of communication with the engineer by the passengers. The light is produced by carburetting air in a manner somewhat similar to that in common use in the numerous portable gas-machines. The air is reduced from the high pressure necessary to operate the brakes to a moderate and steady one. It is then passed into a small iron box containing sponges saturated with , and from these passes to the burners. The light is said to be of good quality and sufficiently bright to see to read fine print in any part of the car. Its cost is much less than gas or any other material commonly used for this purpose on railroads. The communicating apparatus consists of an arrangement of air connections, such that the pulling of a handle in the car starts a whistle on the engine and on the car, and puts the brakes partially on. The attention of the engineer being attracted, he can complete the application of the brakes if he is in a favorable position for stopping, or, if not, release them. The handle once pulled, the passenger can not return it to its place. This can only be done by one of the trainmen, so that improper use of the apparatus is readily detected. This appliance is especially designed to meet the requirements of passengers in the compartment carriages, such as are used abroad. With the American system of cars, the bell-rope furnishes a ready means of communication, while the trainmen are generally within easy call. The lighting and communicating apparatus can be added to carriages after the brake is put in, and but one connection between the carriages is required.
The Circulation of Sap in Trees.—Professor Joseph Böhm has suggested, as a theory to account for the circulation of the sap in plants, that the exhaustion of the water by evaporation from the top of the plant causes a difference in pressure in the adjoining cells, which produces a sucking up of the fluid from the cells that are relatively rich to those that are relatively poor in water. He has also endeavored to make clear what is the purpose of those vessels which run the whole length of deciduous trees, and which can be easily perceived with the naked eye in sections of many species, as the oaks, maples, etc. Generally these vessels have been regarded as air-vessels, but Professor Böhm has been convinced that in many plants they not only receive sap by measured transpiration, but also in consequence of an active exhalation take up a relatively great quantity of water, so that the air fails to penetrate them at the ordinary pressure and only escapes in considerable quantities after the plant has become drier. It has also been shown that the branches of many plants, willows for instance, notwithstanding their vessels are supplied with fluid, are able to take up more water from without, and in such quantities that twigs will increase in weight twenty per cent, in the course of a few days. Professor Böhm's theory corresponds closely with that advanced by Professor Draper in his work on the circulation in plants and animals, and substantially agrees with the views of Herbert Spencer, as expressed in his paper on "Circulation and the Formation of Wood in Plants" ("Transactions of the Linnæan Society," March 1, 1866). It supposes that the sap-bearing cells in the whole plants are subject to a moderate pressure in consequence of the resistance which the water meets on its way from the root to the assimilating leaf. If, however, the branch can take up water through a cut end with little difficulty, a partial absorption of the contents of the vessels into the sap bearing cells will follow, new water will pass through the cut end from without into the vessels, and the limb will become heavier. In this process, the ducts of the willow do not serve as air-tubes, but as water-canals which pour their contents into the pump-system of the sap-bearing cells. These canals become obstructed, after the cuttings have stood for some time in the water, by the growth of cells across the tubes. As soon as the flow of water through the vessels to the higher part of the limb is thus interrupted, the rapid increase of weight ceases. That the cutting does not perish at this stage, but continues to live for several months without any considerable increase of weight, is due to the fact that after the ducts have been closed the circulation of water takes place only through the sap-bearing cells and is greatly retarded. In another series of plants, as the oaks, acacias, catalpas, amorphas, etc., the ducts of the new wood have been found to be penetrable to the air, but neither air nor water could pass through the old wood, because the older veins were closed by transverse cells or gummy substances. The vessels of these plants were really air-vessels, for they held only air of the tension of the atmosphere and were destitute of sap. Yet an uninterrupted stream of sap must be kept up in such plants from the root to the top. It takes place in the same manner as in willow-cuttings, the vessels of which have been closed by transverse cells—that is, the sap is filtrated from cell to cell, so that the balance in the pressure of the contents of the adjoining cells which has been disturbed by transpiration is restored. It follows from this that the tension of the air in the upper sap-bearing cells must be very slight to make a rising of the sap possible. The exhaustion of the air finally reaches its extreme degree at an appointed age of the cells, the air in the cells is cut off from the neighboring vessels, and the factor which produces the rise of sap is thereby eliminated. The wood, which was a living sapwood, becomes a dead heart-wood. This process is accomplished with different degrees of rapidity in different kinds of plants; even in individuals of the same species, circumstances cause many differences in the formation of heart-wood. The final result is, however, always the same, the natural death of the tree by debilitation. The thin outside layer of living wood is no longer sufficient to supply the expanded top with fluid food, no formation of new wood worthy of the name takes place, the limbs die out year by year, and finally only a feeble shoot here and there, with a few leaves of a strangely light color, indicates that there is still a little life in the stem, and this is destined soon to be extinguished. Those trees whose vessels continue to be filled with water in their old age, as the willows, birches, lindens, horse-chestnuts, etc., do not die in this manner, but through a dissolution of their sap-bearing vessels and wood-cells, opening the way for the introduction of fungi-, which settle within them and attack their substance. The process of decomposition spreads and the wood is gradually reduced to dirt, till the tree finally falls or is blown to the ground.
The French Association.—The French Association for the Advancement of the Sciences held its ninth annual meeting at Rheims. The opening address was delivered by the President, M. Krantz, who referred to the growth of the Association since its organization, just after the close of the Franco-German war, and to the results of the Great Exposition of 1878. The progress of the Association has been continuous and marked from year to year, and it now numbers thirty-one hundred and fifty-six adherents. It has a capital exceeding three hundred thousand francs, and has distributed funds in aid of investigation to the amount of about seventy thousand francs. The Secretary, M. Mercadier, stated that five hundred and seventy-two members had been enrolled since the last meeting at Montpellier to the 1st of January, 1880, and that five hundred and sixty inscriptions had been received since then. The Association receives a gift of one thousand francs a year from M. Kuhlmann; the city of Paris and the city of Montpellier, following its example, have instituted funds out of the surpluses remaining from the collections for entertaining the sessions, to provide small subventions; and M. Brunet has given twenty-three thousand eight hundred francs for the foundation of an annual subvention of one thousand francs. More than three hundred papers had been sent in at the opening of the sessions.
English and American Birds.—Mr. H. D. Minot records his impressions of English birds as compared with American in the August number of the "American Naturalist," and his good opinion of American birds is not depreciated by the comparison. Birds are less abundant in England than with us, but are, on the other hand, more accessible and companionable—for the boys in England do not stone, and the men do not shoot them, at every opportunity. They seem to be heavier and slower of flight than in America. This was observed particularly of the wild pigeon, the swift, and the grouse. Furthermore, says Mr. Minot: "I believe I may justly say that as the birds of England are inferior to those of New England in variety, so are they, on the whole, in coloring and in song. Her kingfisher may be as tropical in brilliancy as our humming-bird; her thrushes, swallows, and finches as pretty as any other of their tribe; but with the exquisite and delicate beauty of our wood-warblers, and with the splendor of our tanagers, orioles, and starlings, she has almost nothing among her familiar friends to compare. Then, among her song-birds, of whom I heard nearly all, she has none corresponding as musicians to our hermit-thrush, house-wren, water-warbler, solitary vireo, song-sparrow, or rose-crested grosbeak; yet all these, and many kindred that I might associate with them here, are good singers. To all her songbirds (that I have heard), on the contrary, except two or three, we have singers corresponding, and to all absolutely, I may say without prejudice, equals or superiors, as well as I can judge." The nightingale did not quite meet his anticipations, but he recognized that "it had a most wonderful compass, and was the greatest of all bird vocalists, but with a less individual and exquisite genius than our wood-thrush, yet, to hear that delicious, soft, liquid, warbled trill which she alone can give was a lasting pleasure." The flight of the skylark "is indeed astonishing, though exaggerated by report. . . . His song is an unbroken, ecstatic torrent; but it is shrill, slightly harsh, and not very musical. It is not so rich as our bobolink's roundelay, and its sweetest notes, though they suggest, do not equal, the canary's song, except for their intensity of utterance. All his poetry and the secret of his charm are in his flight." The most individual and only new type of bird-song Mr. Minot heard was that of the wood-lark, "the repetition of a delicate whistle (ch`née), shrill at first, intensifying as the bird rises, and, as he drops, falling in tone and pitch so as to die away upon the ear. It is exquisite." Other singers are the song-thrush, whose music is like our brown thrush's, but with less variety and occasional harsh notes; the blackbird, with a richer and more liquid and at times exceedingly delightful song; the wren, singing with characteristic sweetness and power, the black-cap linnet, and chaffinch, to whose songs Mr. Minot gives only faint and qualified praise. Robin-redbreast is charming on account of its associations. Mr. Minot earnestly commends the collections of birds in the local museums, especially those at Salisbury and Torquay.
Transformation of Sound into Light.—M. Trève, a ship captain, has described to the French Academy of Sciences an experiment with the apparatus called the singing condenser, by which he believes that he produces a transformation of sound into light. If we bring the current of a Ruhmkorff coil to bear upon one of these condensers, the latter will repeat on a larger scale the vibratory movement of the coil. The noise which it makes is due to the vibrations of the air in the condenser under the shock of the electric current. If we put a light pressure upon the leaves of the condenser, the sound will be diminished in proportion as the pressure is increased, till it ceases. Reversing this experiment, M. Trève put a condenser into a Geissler tube, and brought the two poles of the inductive current of the Ruhmkorff coil to bear upon it through the electrodes of the tube. The tube was then connected with an air-pump. The condenser sounded as usual when the current was directed to it under the ordinary atmospheric pressure; as the air was withdrawn, the sound became more feeble, till, when a vacuum was produced, it ceased, and instead of it there shone a clear, bright light, sparkling like pearls, from the leaves of the condenser. It was not like the pale and vague light of the Geissler tubes, but something, he says, quite different, sharp and distinct—a condensed light.
Caves in Japan.—Professor Morse also described a number of artificially constructed caves which he had examined in various parts of Japan, giving sketches of them on the blackboard. These caves varied considerably in their design, but agreed in their general proportions, and were evidently intended as receptacles for the dead. They were excavated in soft rock on the sides of hills—the apertures small, and in some cases showing grooves for the adjustment of slabs of rock or other material to close them. The absence of remains in these caves could be explained by the fact that in earlier times outlaws and refugees often used them as places of shelter and residence, and laws had finally been passed by the governors of some of the districts, causing the caves to be filled up, or their entrances obstructed, to prevent their being used in this manner.