Popular Science Monthly/Volume 31/August 1887/Popular Miscellany
Report upon the Charleston Earthquake.—The United States Geological Survey, according to a communication from Messrs. Dutton and Harden in "Science," has received reports relating to the Charleston earthquake from more than sixteen hundred localities, giving a much larger amount of information than has ever before been collected concerning any one earth-quake. A considerable proportion of the reports were in answer to a printed list of questions which had been sent out, to direct attention to the most distinct and significant features of the phenomena. The first point to receive attention is the magnitude of the area affected by the shocks. The earth-quake was felt in Boston, near Lake George, and at two points in the Adirondacks, at several places in Ontario, Michigan, and Wisconsin (at La Crosse, nine hundred and sixty-seven miles from Charleston, the most remote point within the United States which has given a positive report), in some of the Florida Keys, in Cuba, and in Bermuda, a thousand miles from Charleston. The area within which the shakings were marked enough to attract considerable attention, would be somewhat more than circumscribed by a circle of a thousand miles radius. The movement might, however, have been detected, by instrumental observation, over a much greater area. There are some large tracts within the area which show comparatively feeble intensity. The most conspicuous of them is the Appalachian region. This fact is of interest in its bearing on the supposition that mountain-ranges serve as barriers to the propagation of earthquakes. Another minimum area was in Indiana and Illinois; and it nearly corresponded with the area in which a considerable earthquake occurred on the 6th of February. The coincidence is curious, if not significant. At nearly all places within about two hundred and fifty miles of the center the energy of the shock was very great. Coming nearer to the center, the intensity increased on all sides, with differences in kind as well as in degree. "The phenomena characteristic of the epicentral area cease with something like abruptness as we radiate away from the epicentrum. The central phenomena are those produced by shocks in which the principal component of the motion of the earth is vertical. Proceeding outward, these predominating vertical motions pass, by a very rapid transition, into movements of which the horizontal component is the greater, and in which the undulatory motion becomes pronounced." The rapidity of these transitions, or the shape of the intensity-curve into which they may be translated, is supposed to be dependent upon the total energy and depth below the surface of the shock. The distance from the epicenter to the point where the rate of decline of the intensity is greatest, is simply proportional to the depth of the focus, and is the same whether the energy be greater or less. This gives a rule for estimating the depth of the focus. Applying the rule, we have a computed depth of twelve miles, with a probable error of one or two miles, for the focus of the principal shock at Charleston. There is reason forthat none of the great earthquakes of the last one hundred and fifty years have originated from a much greater, and few from as great, a depth. The city of Charleston was situated at from eight to ten miles outside of the area of maximum intensity. Had the seismic center been ten miles nearer to it, the calamity would have been incomparably greater than it was. The shocks were also probably made easier for the city by the loose nature of the soil and quicksands over which it is built. The time-data have not been fully worked out, but it is thought that they will give a speed of propagation exceeding three miles a second—a rate which "will probably prove unexpected to European seismologists."
Some Popular Errors about the Eskimos.—Mr. John Murdoch has exposed, in the "American Naturalist," a few popular errors in regard to the Eskimos, some of which have found their way into Hovelaque and Hervé's recent book on "Anthropology." Polyandry is not common among them, as is asserted there and by Bancroft, but is very rare, if it exists noticeably at all. Eskimo houses are seldom, if ever, holes dug in the earth, as the French authors say, but wooden, turf-covered lodges, built sometimes over an excavation of only moderate depth, as often wholly upon the surface, or else, farther north, they are the well-known snow-house. The people do not live a torpid existence in winter, but an extremely busy and active one, in employments which call out the energies, in some shape or another, of the whole family. The eating of raw flesh, which has been attributed to this people, is exceptional and usually practiced only under stress. The enormous consumption of fat, also, "supposed to be a physiological necessity to enable them to withstand the excessive cold, is probably the exception rather than the rule, to judge from the accounts of actual observers. It seems quite probable that the amount consumed in most cases is little, if any, greater than that eaten by civilized nations, when we consider that the people who eat the fat of the seal with the flesh, and use oil for a sauce to their dried salmon, have no butter, cream, fat bacon, olive-oil, or lard." The French authors correct one popular error in regard to the relative stature of the Eskimos, and declare that they are but little below the medium stature, having an average height of about five feet three inches, while "medium stature," according to Topinard, in five feet four inches. In comparing several series of measurements of Eskimos, only one was found that at all corroborates the popular opinion of their small size, and that gave the average height of twenty-three men at Cumberland Gulf as five feet 24 inches, still above Topinard's standard of small stature (five feet one and a half inch or less).
The Coming Solar Eclipse.—The total eclipse of the sun of August 19th will occur under circumstances offering unusual facilities for concurrent observation. The line of totality crosses Asia and Europe from Japan to the British Islands, and the phenomenon can be observed with the sun at a good height from all places on this line east of Moscow. Among these points are Tver, Petrovsk, Kineshma, Perm, Tobolsk, Tomsk, Krasnoyarsk, Irkutsk, and several stations in Japan, where the opportunities for observing will be even better than in Russia and Siberia. Professor C. A. Young will have a station at Tver, and parties of English and Italian astronomers will observe in the neighborhood. As nearly all the points in Russia and Siberia are connected by telegraph, the observing parties will have facilities for instantaneous communication with one another.
Disposal of Sewage and Garbage.—Mr. W. Howard White has given to the American Society of Civil Engineers his views as to the comparative value and feasibility of five different methods of disposing of sewage and garbage. The method of dry removal is still in most general use, and costs, in Leeds, England, including removal of ashes and garbage, twenty-four cents per head a year. The great defect of removal by water-carriage, such as prevails in all large cities, is that usually it only takes the nuisance to another place, without abating it. This fact, and the failure of the currents depended upon to carry the stuff far enough away, have led to the introduction of the method of water-carriage with works for purification by precipitation. This is effected at the Knostrop Works, Leeds, by means of a set of settling-basins, with milk of lime as the precipitant. At Frankfort, alumina ferric is to be used. The method of water-carriage, with filtration or irrigation, can be applied with great advantage in small towns; but in cities of more than one hundred thousand inhabitants it is met by the difficulty of getting enough land to make the effectual application of filtration or irrigation practicable. The method of dry removal and making up into salable products is practiced on a large scale at Manchester, England. Urine and fæces partially deodorized with the house-ashes are converted into manure and a variety of useful compounds at a cost of from twenty-four to thirty-seven cents per head a year. The Liernur separate pneumatic system is judged to be more expensive than any other well-arranged method. In some places in England and in Holland, refuse not suitable for the sewers is burned in destructors at small cost. At Leeds, the stuff is fed at the top of the apparatus, and works down gradually to the grate, where fire once started is kept up by the refuse itself. Dr. C. Meymott Tidy says that no single answer can be given to the question of the disposal of sewage. The adviser must sink his hobby and be prepared to find conditions under which he would counsel irrigation, and other conditions under which he would recommend precipitation. Success at one place furnishes no argument that a process will be successful everywhere. His own experience of all kinds of schemes has led him to prefer a scheme combining the principles of precipitation and irrigation. It has the advantages that its efficient working is independent of the weather; and that, if the works are sufficiently large, any emergency of quantity can be met.
Atlantic and Pacific Fishes.—Professor David S. Jordan has published, in the "Proceedings of the United States National Museum," a list of the fishes known off the Pacific coast of America, from the Tropic of Cancer to Panama. Our knowledge of these species is due chiefly to the studies of Dr. Gill, Dr. Günther, Dr. Steidachner, and Professors Jordan and Gilbert; and the work of the few collectors who have given special attention to the subject has in nearly all cases been of exceptional value. Of the four hundred and seven species of fishes now known from the Pacific coast of Mexico and Central America, seventy-one species, or seventeen and a half per cent, are also found on the Atlantic coast. If we add to this some eight hundred species, now known, from the Caribbean Sea and adjacent shores, we have about six per cent of the whole number known as common to the two coasts. With only this proportion of common species, the two faunæ show no greater resemblances than the similarity of physical conditions on the two sides of the continent would lead us to expect. This conclusion is opposed to the views expressed by Dr. Günther in his "Fishes of Central America," where he assumes that nearly one third of the total number of species of marine fishes on the two shores of tropical America will be found to be identical. Hence he infers that there must have been, at a comparatively recent date, a depression of the isthmus, producing an intermingling of the two faunæ. The discrepancy arises from the comparatively limited representation of the two faunæ, at the disposal of Dr. Günther. Several of the identical species are pelagic fishes common to most warm seas. Others are almost cosmopolitan in the tropical waters; while most of the rest often ascend the rivers of the tropics. We may account for their diffusion, perhaps, as we account for the dispersion of fresh-water fishes on the isthmus, on the supposition that they may have crossed from marsh to marsh at some time in the rainy season. Professor Jordan is therefore brought to the conclusion that the fish fauna of the two shores of Central America are substantially distinct, so far as species are concerned, and that the resemblance between them is not so great as to necessitate the hypothesis of the recent existence of a channel across the isthmus.
Progress of Stellar Photography.—From a paper by Professor E. C. Pickering, on "An Investigation in Stellar Photography, conducted at the Harvard College Observatory," it appears that the first work in this branch was an experiment made at the observatory in July, 1850, when, under the direction of Professor W. C. Bond, a satisfactory image of the star α Lyræ was obtained by Mr. J. A. Whipple. Subsequently, the double star α Geminorum gave an elongated image, evidently due to its two components. Objects as bright as these gave but faint images, and no impression was obtained from the pole-star, however long the exposure continued. The experiment was repeated with various stars and clusters, but the work was finally abandoned, owing to the imperfections of the driving-clock and the lack of sensitiveness of the plates. Both of these difficulties were partially remedied in 1857; the research was resumed by Professor G. P. Bond, and the value of stellar photography as a means of determining the positions and brightness of the components of double stars was established. The present research was undertaken in 1882, when it was shown that photography could be used as a means of forming charts of large portions of the sky, and of determining the light and color of stars in all parts of the heavens. Photographs of the trails of polar stars no brighter than the eleventh magnitude were obtained without clock-work. Stellar spectra were obtained of the brighter stars without clock-work, in which all the principal lines were well shown. The investigation having been resumed in 1885, with a larger telescope, one hundred and seventeen stars within 1 degree of the pole, each of them no brighter than the fourteenth magnitude, left trails. The average deviation of the measures of the brightness of these stars on different photographs was less than a tenth of a magnitude, a greater accordance than is given by any other photographic method. A similar result was obtained from the Pleiades, of which group more than fifty stars left trails. Trails are now being photographed of all the stars north of-30º in all right ascensions, and the work has been completed for more than half of the sky. By photographing on the same plate polar stars near their upper and lower culminations, material has been accumulated for determining the atmospheric absorption on each night of observation. A study has been made of the application of photography to the transit-instrument. By placing a large prism in front of the object-glass, excellent stellar spectra have been obtained. An exposure of five minutes gives the spectra of all stars brighter than the sixth magnitude within a region 10º square. About half of the region north of-25º has been photographed in this way. With an exposure of an hour, the spectra of stars no brighter than the ninth magnitude are shown. Over a hundred stars have thus been taken simultaneously on a plate by a single exposure. Miscellaneous observations have been secured of the Pleiades, of the nebula in Orion, of Jupiter's satellites, and of various other objects; also of the new star in Orion, and of its spectrum, and one plate showing that this star must have been much fainter on November 9, 1885, than when discovered five weeks later.
The Prospect for Silk-Culture in the United States.—Dr. C. V. Riley, of the Entomological Division of the Agricultural Bureau, said in the preface to the second edition of his "Manual of Silk-Culture," in 1882, that the elements of successful silk-culture on a large scale were entirely wanting in this country; that "the profits of silk-culture are always so small that extensive operations by organized bodies must prove unprofitable where capital finds so many more lucrative fields for employment; that extensive silk-raising is fraught with dangers that do not beset less ambitious operations," and that silk-culture is to be recommended only as a light and pleasant employment for those members of the farmer's household who either can not do or are not engaged in otherwise remunerative work." In the latest edition of the "Manual" (1886) the author regrets that his original estimates, made in 1879, of the profitableness of the enterprise have been criticised because they had not been realized the trade had, in fact, been passing through a period of depression; and he reiterates the caution that "silk-raising on an extensive scale is fraught with so many dangers, that it is inadvisable to invest capital in such an enterprise." Silk-culture, he says in another place, "is not (and it never has been) an exceedingly profitable business; but it adds vast wealth to the nations engaged in it, for the simple reason that it can be pursued by the humblest and poorest, and requires so little outlay. The question of its establishment in the United States is, as I have elsewhere said, a question of adding to our own productive resources. There are hundreds of thousands of families in the United States to-day who would be most willing to add a few dollars to their annual income, by giving light and easy employment for a few months each year to the more aged, to the young, and especially to the women of the family, who may have no other means of profitably employing their time."
Wood and Metal for Railroad-Ties.—M. Henri Mathieu, chief-engineer of the French railway du Midi, from observations on the consumption of the wood ties on French railways, has found that their duration depends upon several factors, among which are the material employed, the climate, the ground, and the ballasting. It principally depends upon the system of preparing the ties, and the quality of the antiseptic material; and the observations made on one line often differ from those made on another line. Averaging the results—oak ties, not prepared, last fourteen years; when creosoted, eighteen years. Creosoted beech ties last from eight to ten years; creosoted ties of pines of the Landes, twelve years; prepared with sulphate of copper, from eight to twelve years. While, as between wood and the substitution of metal for it, M. Mathieu favors sticking to wood, he admits that the substitution of steel for iron is an important matter, and that one of the principal inconveniences of the metallic ties—want of solidity in the joints—may be obviated by careful attention during the first two years, which will make the rails and the sleepers solid. Metallic ties should be made heavier than they are, if they are to succeed. They had been laid, at the beginning of 1884, on 5,708 kilometres of lines in Germany, Austria, Holland, Belgium, and Switzerland.
Some Ancient Philosophy.—A book called "Speculum Mundi, or a Glass representing the Face of the World," published in 1670, gives a curious picture of what passed for science before the great modern discoveries were made. It consists of a chapter on each of the six days of creation. It says that the world was at first an unfashioned lump. Having disposed of the question of the firmament as best it could, it says of the air that the highest region is said to be "exceeding hot," because of the stars. Meteors and comets, it informs us, are "composed of Vapours or Fumes—a kinde of Smoak." Some of these vapors "transcend" very high, "even to the Starry Heaven itself; which is witnessed by our best Modern Astronomers, who have observed many Comets above the Moon." Great events are connected with comets, because those bodies consist of "many hot and dry Exhalations" and "distemper the Air," which "the Bellows of the Body suck in and receive; insomuch that there cannot but be Sickness, Plague, and much mortality." Moreover, these "poysonous breathings" are "very apt so to disorder and dry up the Blood in Humane Bodies, that thereby great store of red and a dust choler may be purchased; and this stirreth up to anger with the thought of many furious and violent actions, and so by consequence to war." Thunder is caused "by reason of Hot and Dry Exhalations shut within the cloud, which, seeking to get out, with great Violence do knock and rend the cloud." The hot and dry exhalation in escaping is set on fire by the violence, and becomes lightning, when it often continues burning until it falls to the ground. "And oftentimes a great stone is blown out of the cloud with it; whose cause is also natural." For, when the exhalation is drawn up from the earth, it sometimes takes earthy matter "like unto the finest sand" with it, and this, "through the moisture which it getteth in the Air," "clottereth together," and, "by the excessive heat which it findeth in the general matter of the exhalation," becomes hard like a brick. Sometimes the exhalations carry up also frogs, fishes, and grain, or the vehement heat of the sun draws milk, and we are treated to curious showers of corresponding nature. We are also informed that the long, streaming threads seen floating in the air, and vulgarly supposed to be spiders' webs, are nothing of the kind, but meteors, which "may rightly be supposed to proceed out of a through boyled or digested vapour, being mixed with earthy and slimy Exhalations."
Tourist and Alpine Clubs.—A manual of the Tourist Unions of the world under which designation are included Mountain and Alpine clubs and the like published by Herr R. Koehler at Eisenach, shows that these associations, which are really of recent origin, have thriven greatly. The census of them gives a total of 78 clubs or unions, with 775 sections and 79,955 members. Of these, 73 clubs, with 770 sections and 79,365 members, are in Europe; four clubs, with 590 members, in America; and one club in Asia. The largest of them all is the German and Austrian Alpine Union, which has 109 sections and 12,274 members. Their special organizations and objects vary according to the characteristics of the nation in which they severally exist, but the common object of them all is the study, exploration, and enjoyment of natural scenery, with a prominent place given to mountain-climbing.
Artificial Rubles.—Mr. George F. Kunz recently read a paper before the New York Academy of Sciences on some artificial rubies that have been offered in the market of Paris as genuine rubies from a new locality. On examination of specimens of the stones the author found their principal distinguishing characteristic to be the presence of spherical bubbles, rarely pear-shaped, or having stringy portions showing how they had moved, but with the ends always rounded, and presenting a cloudy appearance or an arrangement in wavy groups. In natural rubies the cavities are always angular or crystalline in outline, and are usually filled with liquid; or, sometimes they are arranged with the lines of growth, forming part of a feather, as it is called by jewelers. In many genuine rubies we find a silky structure which appears under the microscope to be a series of cuneiform or acicular crystals, usually iridescent. No traces of these have been found in the artificial specimens. The stones are about equally hard and of nearly equal specific gravity with genuine rubies. Their color is good, but not so brilliant as that of a very fine ruby. The syndicate of diamonds and precious stones of Paris has directed that all stones of this kind shall be marked artificial, else they will be considered fraudulent, and sellers of them will be dealt with accordingly.