Popular Science Monthly/Volume 42/December 1892/Popular Miscellany
|←Publications Received|| Popular Science Monthly Volume 42 December 1892 (1892)
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Reality of Geological Catastrophes.—In a review of the history of the theories of the development of the earth's crust—that of uniformitarianism and that of catastrophes—in his address at the British Association, Prof. Archibald Geikie spoke of a modification or enlargement of the uniformitarian doctrine which has been brought about by continued investigation of the terrestrial crust and consequent increase of knowledge respecting the history of the earth. "Though Hutton and Playfair believed in periodical catastrophes, and indeed required these to recur in order to renew and preserve the habitable condition of our planet, their successors gradually came to view with repugnance any appeal to abnormal, and especially to violent, manifestations of terrestrial vigor, and even persuaded themselves that such slow and comparatively feeble action as had been witnessed by man could alone be recognized in the evidence from which geological history must be compiled. Well do I remember in my own boyhood what a cardinal article of faith this prepossession had become. We were taught by our great and honored master, Lyell, to believe implicitly in gentle and uniform operations, extended over indefinite periods of time, though possibly some, with the zeal of partisans, carried this belief to an extreme which Lyell himself did not approve. The most stupendous marks of terrestrial disturbance, such as the structure of great mountain chains, were deemed to be more satisfactorily accounted for by slow movements prolonged through indefinite ages than by any sudden convulsion. What the more extreme members of the uniformitarian school failed to perceive was the absence of all evidence that terrestrial catastrophes even on a colossal scale might not be a part of the present economy of this globe. Such occurrences might never seriously affect the whole earth at one time, and might return at such wide intervals that no example of them has yet been chronicled by man. But that they have occurred again and again, and even within comparatively recent geological times, hardly admits of serious doubt. How far at different epochs and in various degrees they may have included the operation of cosmical influences lying wholly outside the planet, and how far they have resulted from movements within the body of the planet itself, must remain for further inquiry. Yet the admission that they have played a part in geological history may be freely made without impairing the real value of the Huttonian doctrine, that in the interpretation of this history our main guide must be a knowledge of the existing processes of terrestrial change."
Physiological Action at a Distance.—Discussing the cause of physiological action at a distance, in the British Association, Prof. Errera, of Brussels, said that most vegetable organs were sensitive to the influences of the environment, and responded to these stimuli, as long as they were capable of growth, by bending in different directions—phenomena familiar to vegetable physiologists. But two years ago other phenomena were observed, which did not appear to belong to any of the known categories. Elfving found that pieces of iron and, to a less-degree, of zinc or aluminium, as well as different organic substances, such as sealing-wax, rosin, etc., attracted the growing sporangium-bearing filaments of a mold (Phycomyces nitens). All other metals Elfving found inactive, but the filaments of the mold itself showed a mutual repulsion. This movement, however, Prof. Errera considered wholly due to the hygroscopic condition of the stimulatory substance. The sensibility of phycomyces, he observed, was in fact so great that it might be used as a reagent to test the existence of hydroscopic power, which he illustrated in the case of camphor, the hydroscopic condition of which, after one experiment, was proved by careful weighing, although it was unknown to chemists. All the experiments succeeded in a saturated atmosphere, showing that hydrotropism was not due, as generally believed, to difference in the hygrometric state of the air. To sum up, concluded the author, the apparently mysterious action of iron on phycomyces was nothing but a matter of hydrotropism, and hydrotropism itself, negative or positive, was the bending of a vegetable organ toward the points, not where it would find a minimum or maximum of moisture, but where it would transpire most or least.
Disappearance of Wild Plants.—The report of the committee of the British Association on the disappearance of wild plants from their native habitats mentioned fifty of the less common wild plants of the west of Scotland which had been greatly reduced in number in recent years from natural and other causes. The natural causes were due to agriculture, drainage, industry, and the growth of towns and villages, and seemed to be outside of the scope of protective measures. In many cases disappearance is attributable to the removal of specimens by collectors for the formation of herbariums, and of plants with showy flowers and ferns for sale. Herbariums are essential to the study of botany, but the committee thought their multiplication might be made unnecessary by the formation of local collections for reference. Collections for sale might be prevented by the intervention of proprietors. But it was difficult to suggest any course of prohibitive measures. In the discussion the too specific designation of places where choice plants can be found was deprecated as making access to them too easy to unscrupulous searchers. A resolution was passed on the preservation of birds and eggs; and Canon Tristram, speaking to it, put in a plea for the preservation of birds of prey, pointing to the mice-plague in Dumfries and Lanark shires as a result of destroying the balance of Nature by wholesale killing of such birds.
Prize Essays on Alcohol.—The American Medical Temperance Association, through the kindness of J. H. Kellogg, M. D., of Battle Creek, Mich., offers the following prizes:
1. One hundred dollars for the best essay On the Physical Action of Alcohol, based on Original Research and Experiment.
2. One hundred dollars for the best essay On the Non-Alcoholic Treatment of Disease.
These essays must be sent to the secretary of the committee, Dr. Crothers, Hartford, Conn., on or before May 1, 1893. They should be in type-writing, with the author's name in a sealed envelope, with motto to distinguish it. The report of the committee will be announced at the annual meeting at Milwaukee, Wis., in June, 1893, and the successful essays read. These essays will be the property of the Association, and will be published at the discretion of the committee. All essays are to be scientific, and without restrictions as to length, and limited to physicians of this country. Address all inquiries to T. D. Crothers, M. D., secretary of committee, Hartford, Conn.
Devolution of the Little Toe.—The thumb and great toe of men are two-jointed, while the other fingers and toes are three-jointed. But it has been observed, in the examinations of skeletons, that the little toe is occasionally two-jointed; the middle and terminal phalanges having been so united that they can hardly be distinguished. This variation occurs in about thirty-six per cent of the cases, and usually affects both feet alike, but appears rather more frequently in women than in men. Pressure of the shoes has been assigned as a cause of it, but it has been observed in children under seven years old, and even in embryos as often as in adults, and in circles where tightly fitting shoes are not worn. Dr. Pfitzner, who has made a special study of the subject, has come to the conclusion that the little toe is in process of degeneration, and that without its being possible to show that it is suffering an adaptation to any external mechanically operating influence. Corresponding to this, certain processes of reduction are going on in the muscular apparatus. The whole phenomenon is of interest, because we are witnessing its beginning, and can certainly predict its outcome in the final reduction of the little toe to two joints.
The Exact Point of the Pole.—If any of our arctic explorers ever reach the pole, they will be confronted by a very difficult problem in determining the exact point. Geographical determinations increase in difficulty on approaching the pole, on account of the narrowing of the degrees of longitude, and the compass, sextant (if the weather is cloudy), and chronometer are of little use then. A process for taking the point at the pole has been described by M. E. Durand Gréville, which depends on the properties of the gyroscope. The apparatus consists of two gyroscopes and a plumb-line. To determine the latitude a gyroscope which has been oriented by its axis to the pole of the sky—or a gyroscope-compass—is employed. The angle which its axis makes with the vertical of the place is complementary to the latitude. To determine the longitude, a second gyroscope is needed, which has been adjusted so as to turn in a plane parallel to the meridian of the point of departure. The plane of the gyroscope-compass being necessarily parallel to the equator, if we project the vertical of the place upon it, and measure the angle which that projection makes with the line of intersection of the planes of the two gyroscopes, we shall have the difference in longitude of the point of departure and the point of arrival. A practical arrangement for taking this measure has been devised by M. Trouvé. Before starting, the travelers set in motion the gyroscope-compass and the gyroscope whose plane is the meridian of the point of departure. When the position of a point is to be determined, the axes of the two gyroscopes are conveyed parallel to themselves, and the vertical of the point reached is taken with a plumb-line. If the axis of the gyroscope-compass is parallel to the plumb-line, the balloon is immediately above the pole. The result is not affected by height above the earth's surface, for the directions of the three instruments continue the same at all points of the same vertical.
Canadian Names and Places.—Dr. George M. Dawson observes, in his Geography of Canada, that throughout the country many of the original Indian names of places have been adopted and perpetuated by the whites, but in most cases they have suffered abbreviation or other changes in the process. In general the native names are found to be of a descriptive character, and to express some noted feature or product of each locality. Taking instances from different parts of the country and in several dialects, Nictau means "forks of a river"; Shediac, "running far back"; Matapedia, "roughly flowing"; Quebec, "a strait or an obstruction"; Toronto, "a tree in the water"; Winnipeg, "muddy water"; Saskatchewan, "rapid current." It is further noteworthy that in many cases the principal villages or places of resort of the Indians have since become the sites of towns or cities. This depends on the circumstance that the whites first sought such places for purposes of trade, but chiefly on the fact that the Indians selected localities where natural lines of travel, such as rivers, converged, or were interrupted by falls or rapids, necessitating portages; also such places as sheltered havens or harbors on the sea-coast or the shores of the Great Lakes.
Vegetation of New Guinea.—So great a wealth of botanical material has been collected in New Guinea that there are now as many of the higher plants of that country known to science as of German plants, or about two thousand. Inasmuch as the component parts of the forest change in extraordinarily short distances, it may be expected that at least three times as many species will ultimately become known. The island has furnished such an abundance of important and prominent new types, that, as respects plant life, it may be regarded as one of the most interesting and beautiful parts of the earth. The close relationship often supposed to exist between the north Australian flora and that of New Guinea has not been confirmed. It is true that the savannas of the Fly River, covered with eucalyptuses, myrtaceæ, and proteaceæ, correspond not only in their outward habitus, but also in composition, with the formation of York Peninsula; but the typical Australian flora is quite foreign to New Guinea, and there is no ground for the supposition that the island was at one time inhabited by Australian species. The palm flora of the island is one of the richest in the world; almost every district is distinguished by endemic species. The age of the island must be very great; the large number of indigenous genera and species testify to this; of the former, at least fifty are already known.
Geographical Development of Coast-lines.—Summing up the points of his paper in the British Association on the Geographical Development of Coast-lines, Prof. James Geikie arrives at the general conclusion that the coast-lines of the globe are of very unequal age. Those of the Atlantic were determined as far back as Palæozoic times by great mountain uplifts along the margin of the continental plateau. Since the close of that period many crustal oscillations have taken place, but no grand mountain ranges have again been ridged up on the Atlantic seaboard. Meanwhile the Palæozoic mountain-chains, as was shown, have suffered extensive denudation, have been planed down to the sea-level, and even submerged. Subsequently converted into land, wholly or partially as the case may have been, they now present the appearance of plains and plateaus of erosion, often deeply indented by the sea. No true mountains of elevation are met with anywhere in the coast-lands of the Atlantic, while volcanic action has well-nigh ceased. In short, the Atlantic margins have reached a stage of comparative stability. The trough itself, however, is traversed by at least two well-marked banks of upheaval—the great meridional Dolphin Ridge, and the approximately transmeridional Faröe-Icelandic belt—both of them bearing volcanic islands. But while the coast-lands of the Atlantic proper attained relative stability at an early period, those of the Mediterranean and Caribbean depressions have up to recent times been the scenes of great crustal disturbance. Gigantic mountain-chains were uplifted along their margins at so late a period as the Tertiary, and their shores still witness volcanic activity. It is upon the margins and within the troughs of the Pacific Ocean, however, that subterranean action is now most remarkably developed. The coast-lines of that great basin are everywhere formed of grand uplifts and volcanic ranges, which, broadly speaking, are comparable in age to those of the Mediterranean and Caribbean depressions. Along the northeast margin of the Indian Ocean the coast-lines resemble those of the Pacific, being of like recent age, and similarly marked by the presence of numerous volcanoes. The northern and western shores, however (as in Hindostan, Arabia, and East Africa), have been determined rather by regional elevation or by subsidence of the ocean floor than by axial uplifts—the chief crustal disturbances dating back to an earlier period than those of the East Indian Archipelago. It is in keeping with this greater age of the western and northern coast-lands of the Indian Ocean that volcanic action is now less strongly manifested in their vicinity.
The Story which Scenery tells.—"The law of evolution," said Prof. Archibald Geikie at the British Association, "is written as legibly on the landscapes of the earth as on any other page of the book of Nature. Not only do we recognize that the existing topography of the continents, instead of being primeval in origin, has gradually been developed after many precedent mutations, but we are enabled to trace these earlier revolutions in the structure of every hill and glen. Each mountain-chain is thus found to be a memorial of many successive stages in geographical evolution. Within certain limits, land and sea have changed places again and again. Volcanoes have broken out and have become extinct in many countries long before the advent of man. Whole tribes of plants and animals have meanwhile come and gone, and in leaving their remains behind them as monuments at once of the slow development of organic types and of the prolonged vicissitudes of the terrestrial surface, have furnished materials for a chronological arrangement of the earth's topographical features. Nor is it only from the organisms of former epochs that broad generalizations may be drawn regarding revolutions in geography. The living plants and animals of to-day have been discovered to be eloquent of ancient geographical features that have long since vanished. In their distribution they tell us that climates have changed, that islands have been disjoined from continents, that oceans once united have been divided from each other, or once separate have now been joined; that some tracts of land have disappeared, while others for prolonged periods of time have remained in isolation. The present and the past are thus linked together, not merely by dead matter, but by the world of living things, into one vast system of continuous progression."
House "Leader Pipes" as Lightning Rods.—Mr. W. H. Preece called attention in the British Association to a new danger in the destruction of lightning protectors by recent municipal legislation. He said that the immunity of private houses from being struck by lightning is very marked, and this is considered to be due to the fact that the lead on the roofs and the iron stack-pipes that drain these roofs, connected as they are together, form admirable lightning protectors. Any charge of atmospheric electricity which may fall upon a house so protected is conveyed harmlessly away to the earth. British householders are now required to remove these pipes from direct connection with the drains, and to leave an air-space between the end of the pipe and the grating of the drain. The result is that the electric conduction of the pipe is broken, the stack-pipe ceases to be a lightning protector, and houses are left exposed to the danger of atmospheric electricity. The remedy is very simple. The pipe need not be entirely cut away. Three fourths of its circular section may be removed for the distance required, and one fourth may be left to maintain the old electrical connection; or, if the separation has been effected, then the stack-pipe should be connected with the drain by a wire or rod so as to restore a path for the charge to the earth. Householders are also now compelled to put up stack-pipes to ventilate their soil-pipes, erecting above their roofs a metal tube forming a prominent object exposed to the atmospheric charge, and terminating frequently in an earthenware pipe on the first floor. They are thus liable to be struck by lightning without being offered any means of escape. The tubes should be connected electrically with the earth either directly or indirectly through the stack-pipes, which would then make them sources of safety rather than of danger.
A Haida Indian Pole-raising.—The keeang poles of the Haida Indians of the Queen Charlotte Islands, according to Mr. Alexander Mackenzie's account of them, were erected to commemorate the event of a chief taking position in the tribe by building a house and making a distribution of all his property. Each pole has also an individual and distinguishing name. Thus, one of the poles at Masset is named Que-tilk-kep-tzoo, meaning "watcher for arrivals" or "looking" or "watching for arrivals." It was erected by a Haida chief named Stultah, on his decision to build a new lodge. The occasion, as usual, was marked by a large distribution of property, hundreds of blankets and other valuables being given away to all who assisted at the making of the pole, or who were invited to the ceremony. When it was decided to erect a keeang and build a lodge, invitations were sent to the tribes in the vicinity to attend, and on arrival the people were received by dancers in costume and hospitably treated and feasted. When all the Indians from adjacent places were assembled, at the appointed time they proceeded to the place selected for the erection of the pole. A hole seven, eight, or ten feet deep having been dug, the pole was moved on rollers till the butt was in a proper position to slip into it. Large ropes were fastened to the pole and gangs of men, women, and children took hold of the ends at a considerable distance away. The most able-bodied men advanced to the pole, standing so close all along on each side that they touched each other, and grasping the pole from underneath they raised it up by sheer strength, by a succession of lifts, as high as their heads, while others placed supports under it at each successive lift. Stout poles tied together like shears were then brought into play, while the lifters took sharp-pointed poles, about eight feet long, and standing in their former positions, lifted the pole (which was immediately supported by the men with the shears) by means of these sticks, until it attained an angle of about forty-five degrees. The butt was then gradually slipped into its place and the gangs at the ropes, who had been inactive all this time, got the signal to haul, when, amid the most indescribable bellowing, hallooing, and yelling, the pole was gradually and surely elevated to the perpendicular position. When the setting was completed, the crowd adjourned to the house of the owner, who feasted the people, and afterward took the place of Eitlahgeet, great chief. Next he distributes his property, a task requiring great discrimination. Often he adopts a new name. When he proclaims to the crowd that he is quite impoverished and has distributed all his effects, they appear to be delighted, and regard him as indeed a great chief.
The Races of Pern.—According to Señor F. A. Pezet, the aboriginal or Indian race which populated Peru, 12,000,000 souls strong when the Spaniards conquered the country, still holds its own, although it has to a great extent degenerated through the miseries which, during centuries, it endured at the hands of its conquerors. It represents to-day about fifty-seven per cent of the entire population. In the interior of Peru it has kept in many places quite pure, not having mixed with any of the other races that have been brought into the country. There are tribes existing to-day with the old Inca Indian features quite distinct, and among these people there is a great and natural intellect. The other great race is the European, or white, imported from Spain at the time of the conquest, which has ever been on the increase since then. It represents to-day about twenty per cent of the population, and is spread over the whole country, but particularly on the coast. As the Peruvian Indian was made to slave at the mines for his Spanish master, the Spaniards had to introduce Africans to till the ground and work on the cotton and sugar estates along the coast. No Africans have come to the country since slavery was abolished in 1854, and the race has been confined to some of the agricultural districts, and is now rapidly dying out. In its place are the "mestizo" and "zambo," cross-breeds of blacks with whites and with Indians. The cross-breed of whites with Indians has produced the "cholo" race, which of all castes is to-day the most numerous. These mixed races represent about twenty-three per cent of the whole population. Of some fifty thousand Chinese imported since 1854, to be agricultural laborers, the greater part have settled for good, and not a few have embraced the Christian faith and married with Indians, cholos, zanibos, mestizos, blacks, and whites, thereby forming a diversity of castes.
Ventilation at the Top and at the Bottom of Rooms.—The impression, which is very common, and is even held by engineers, that impure air, on account of its superior weight, accumulates to excess in the lower parts of rooms, while the upper parts are free from it, and that ventilation should be applied near the floor rather than near the ceiling, is controverted in the Sanitarian by Dr. W. H. Thayer. The property of gases to diffuse and intermix with one another, irrespective of relative densities, is lost sight of by these authorities. Dr. Thayer finds that the carbonic-acid gas of respiration and illumination will eventually be equally diffused through the atmosphere, although it is retained at the upper part of a room as long as the high temperature continues; and that it never, under any circumstances, is precipitated in excess in the lower part of the room. This conclusion, partly drawn from the philosophy of the matter, has been amply verified by experiments. Dr. H. Cresson Stiles, of the Metropolitan Board of Health, having analyzed the air of many public schools, hospitals, theatres, and churches, found the air taken from near the ceiling always more highly charged with carbonic acid than that in the lower parts of a room, with the difference often very marked. St. Ann's Church, Brooklyn, which was ventilated on the "bottom ventilation" theory, was found to be badly ventilated, with the carbonic acid in the gallery at the close of the service in larger quantity than near the floor. The ventilation of the hall of the old Brooklyn Institute was nearly perfect, and was all through large openings in the ceiling.
Life on Mount Roraima.—Mount Roraima, in British Guiana, which was first ascended in 1884 by Mr. Everard Im Thurm, was again climbed in November, 1891, by Mr. E. Cromer and Mr. Seyler, two collectors of orchids. Exploring the top, the adventurers found toward the south many gigantic and marvelously shaped rocks that seemed to form, as Mr. Cromer described them, "majestic palaces, churches, and fortresses." Other smaller rocks resembled pyramids, umbrellas, and kettles, and one bore a striking likeness to the statue of a man. Between these grotesque masses of rocks were innumerable lochs, some joined together by canals, most of which were shallow, although here and there a depth of six feet was found. Many new species of orchids and other plants were found; but the mountain-top seemed almost destitute of animal life. Mr. Cromer noticed one black butterfly, a few spiders, some small frogs, some small lizards, and a small, dark-colored mammal, which he supposed was a species of kibihee, and on his approach gave a sound like a whistle, and swiftly crept into a hiding-place between the rocks. The lakes on the summit, which cover a considerable area, were swarming with a sort of black beetle. Mr. Cromer and his companion are the first men who have stayed a night on the top of Roraima.
The Mentone Skeletons.—The grottoes of Baussé Roussé, or of Mentone, as they are commonly called, are nine in number, and seven of them were inhabited by Quaternary man. M. E. Rivière, who owns them, explored certain of them in 1872, 1873, and 1875, and recovered several human skeletons and interesting relics from them. A second entry was made into one of them, the Barma Grande, last winter, during the owner's absence and without his knowledge, and several other skeletons and relics were obtained in it. Of the two which have been most fully excavated one is the skeleton of an old man, and the other of a young man of about eighteen years of age. They both appear to be of the Cro Magnon race, and are of fairly large stature. They were adorned with collars of sea-shells, bored for stringing, and of canine teeth of the deer, and vertebræ of fish (salmon and trout). The skeletons, shells, teeth, and vertebræ are all colored a curious red, dotted with bright points, which is derived from the dust of specular iron, with which the bodies of the adults were covered immediately after death. The arms and utensils found immediately in contact with the skeletons consisted of a cut flint seventeen centimetres long by fifty-one millimetres broad, which was situated behind the head of the old man, a scraper, and a curious article of bone or deer horn in the shape of a double ovoid, marked on the surface with numerous irregular and irregularly spaced striæ.
Distribution of Land-shells.—Land-shells, according to Mr. W. H. Dall's Instructions for collecting Mollusks, are found at all elevations, from the beaches moist with sea-spray to the Alpine heights of fourteen thousand feet in the vicinity of perpetual snow. Some are subterranean in their habits, pursuing earth-worms through their burrows, or nestling in the recesses of bones in ancient graveyards. Others are contented with the protection afforded by dead leaves, decaying logs, under the bark starting from rotten stumps, or in the shelter of loose stones and bowlders. Other groups live on the leaves of sedges, grass, and shrubbery, retreating to the soil for winter quarters; some highly colored species live permanently in the tree-tops of tropical forests. In arid regions they seek the shade of stones, attach themselves to the stems of cacti or other desert plants, or even adhere to the sunburned surfaces of rocks so hot as to be uncomfortable to the touch. The color of the shell bears a certain relation to its favorite station. The tree-living forms are brightest and most varied; the moss-lovers and terrestrial species are usually dull, horny, or greenish, but often have a brilliant, polished, or delicately sculptured surface; while subterranean forms are pale or pellucid. The slugs are generally nocturnal, and retreat to holes and crevices. In general, limestone regions are most favorable for land-shells, and those of flinty rock least advantageous. Woods of resinous trees are unsuited to their tastes, while soft woods of deciduous trees are congenial to them. Some pungent herbs are noxious to them; but nettles are a favorite haunt of certain small land-shells. Spring is the most active season for snails; they attain their fullest development toward midsummer; and as winter approaches they penetrate the ground or in warm regions attach themselves to the bark of trees or to stones for a period of hibernation. They close the aperture of the shell with a leathery secretion, sometimes strengthened by more or less limy matter, or, if naked, may surround themselves with it like a cocoon.
Value of Scientific Amateurs.—Is it not true (asked Prof. Arthur Schuster in the British Association) that the one distinctive feature which separates England from all other countries in the world is the prominent part played by the scientific amateur, and is it not also true that our modern system of education tends to destroy the amateur? By amateur I do not necessarily mean a man who has other occupations and only takes up science in his leisure hours, but rather one who has had no academical training, at any rate in that branch of knowledge which he finally selects for study. We may, perhaps, best define an amateur as one who learns his science as he wants it and when he wants it. I should call Faraday an amateur. He would have been impossible in another country; perhaps he would be impossible in the days of the Science and Art Department. Other names will occur to you, the most typical and eminent being that of Joule. We are in danger of losing one great and necessary factor in the origination of scientific ideas. If I am right, there is a distinct advantage in having one section of scientific men beginning their work untrammeled by preconceived notions, which a systematic training in science is bound to instill. If school examinations could be more general, if scientific theories could only be taught at an age when a man is able to form an independent judgment, there might be some hope of retaining that originality of ideas which has been a distinctive feature of this country, and enabled our amateurs to hold a prominent position in the history of science. At present a knowledge of scientific theories seems to me to kill all knowledge of scientific facts. It is by no means true that a complete knowledge of everything that has a bearing on a particular subject is always necessary to success in an original investigation. In many cases such knowledge is essential, in others it is a hindrance. Different types of men incline to different types of research, and it is well to preserve the dual struggle.
What caused the Ice Age?—In their paper in the British Association on The Cause of the Ice Age, Messrs. P. F. Kendall and J. W. Gray maintain that the Glacial period came on with extreme slowness; that it was of long duration; that it passed away very abruptly and very recently, probably about ten thousand years ago; and that the geological record, though yielding evidence of ancient glaciers, yet was without trace of any previous Glacial period. They criticised the existing theories of the cause of the Ice age, and urged that the ingenious theory of Croll was objectionable upon several grounds. It was linked with a chronology which, even with the reservations made by Sir Robert Ball, was not reconcilable with geological facts. It involved the occurrence of repeated Glacial periods, and accounted neither for the very gradual approach nor the very abrupt departure of the cold. The theory of Mr. Upham, of the United States Geological Survey, that a great series of continental uplifts had raised enormous areas of the Northern Hemisphere above the snow-line, was based on evidence valid in itself, but failed to prove that the uplift was synchronous or coincided with the Glacial period. Further, there was irrefragable evidence that the British Isles stood at almost absolutely the same level as at present. Enormous ice-sheets swathed the whole of the northern and western portions of Britain. An explanation which would not apply to the British Isles might safely be rejected. The authors, although they formulate no theory of their own, invite the attention of astronomers to the suggestion that as the sun has undergone a secular cooling such as the president, Sir Archibald Geikie, declared in his address had happened to the earth, the Glacial period was a consequence of this cooling. This would perhaps account for the gradual refrigeration, leaving not the Ice age, but the genial period which suddenly supervened, to be accounted for. Variations in solar radiation by the operation of the same causes that produce sun-spots do beyond doubt occur; and the sudden blazing out of new stars, like that in Auriga, are facts which suggest almost unlimited possibilities of the rejuvenescence of suns. It may well be that the Glacial period is a phenomenon attendant upon the decrepitude of the sun, and the first of a series whose second term may be nearer at hand than geologists or laymen have previously suspected.
Depth of the Atmosphere.—Calculations based on the observation of the refraction of light have caused it to be supposed that the air becomes so rare at the height of about sixty miles that that distance may be regarded as the limit to its sensible extent; but other calculations, made during the present century, of the distance from the earth at which meteors ignite, indicate that the atmosphere extends to upward of a hundred miles. The question is thus presented, says M. Forster, in a paper on the subject, whether the incandescence of these meteors is caused by the resistance of an earthly atmosphere—that is, of oxygen and nitrogen moving with the earth—or is developed in an interstellar atmosphere. The fact that the aurora borealis reaches heights of about four hundred miles tells in favor of the latter hypothesis. The orbits of some comets and the satellites of Jupiter are subject to changes which can be explained only by the action of a resisting medium, and it would be desirable to determine from solar analysis whether the medium in which the aurora exhibits itself is differently composed from our atmosphere, either of gases emanating from the sun or those produced by the explosion of meteoric bodies. The luminous clouds, of which Mr. O. Jesse has made a special study, are objects of great importance in the study of the circulation of the upper atmospheric strata.
Cyrus W. Field.— Mr. Cyrus W. Field, who died at his summer home near this city, July 12th, will be best remembered for his agency in the laying of the Atlantic cables, by which methods of communication and of transacting business between this country and Europe have been revolutionized. Without him they would not have been put in operation for many years later than they were, if at all.
Mr. Field was born in Stockbridge, Mass., in 1819, began his business life as a clerk in A. T. Stewart's store at one dollar a week, and at the end of his term of apprenticeship set up in business for himself as a junk-dealer and paper-maker. He became interested in submarine telegraphy in 1853, and induced a few capitalists to join with him in the Atlantic telegraph enterprise. After thirteen years of effort, fifty journeys across the Atlantic, and many failures, the lines were established, and Mr. Field received the honors that were his due. Several years afterward, Mr. Field engaged in the enterprise of building the elevated railroads in New York city, and materially contributed by his energy to their speedy completion.
National Characteristics in Science.— In his address before the Physical Section of the British Association Prof. Arthur Schuster spoke of the peculiarities possessed by each nation which make it better fitted than its neighbors to do some particular part of the work on which the progress of science depends. No country, for instance, has rivaled France in the domain of accurate measurement, with which the names of Regnault and Amagat are associated, and the International Bureau of Weights and Measures has its fitting home in Paris. The best work of the German universities seems to consist in the following up of some theory to its logical conclusions and submitting it to the test of experiment. The speaker doubted whether the efforts to transplant the research work of German universities into England will prove successful. Does it not seem well to let each country take that share of work for which the natural growth of its character and its educational establishment best adapt it? As far as the work of the Physical Section is concerned, the strongest domain of English students has been that of mathematical physics. Look at the work done in Great Britain during the last two centuries—the work not only in physics, but in astronomy, chemistry, and biology.
Cause of the Bursting of Peat-hogs.—The curious phenomena of the swelling and bursting of peat-bogs have been studied by Herr Klinge. They generally occur after heavy rains, and are preceded by detonations and earth vibrations. A muddy stream issues from them, of varying fluidity, rolling along lumps of peat. Then the mud hardens and the bog sinks back, forming a funnel-shaped pool. The bogs studied by the author have been mostly on high ground, not in valleys. He believes that the eruptions are not caused either by excessive absorption of moisture or by gas explosions—the theories most readily suggested—but by land-slips, collapses, etc., of ground under the bog, which permit water or liquid mud to enter. This breaks up the bog mechanically, mixes with it and fluidifies it, and produces the outburst at the surface. The limestone formations in Ireland, with their large caverns and masses of water, are naturally subject to these collapses, which, with the vibrations they induce, are more frequent in wet years. The heavy rains preceding the bog eruptions are thus to be regarded as only an indirect cause of them. Herr Klinge supposes that similar eruptions occurred in past geological periods, the Carboniferous, for example, in some cases where fossil tree-stems are found in upright position.