Chapter IV: Part 4

Once there was a little blue fox, and his name was Eichkao, and he was a thief. So he built his house down deep among the rocks under the moss on the Mist Island, and his little fox children used to stay down among the rocks. There they would gurgle, gurgle, gurgle, whenever they heard anybody walking over their heads. Eichkao and his fox wife used to run all round over the rocks to find something for them to eat, and whenever Eichkao saw anybody coming he would go clin-n-n-g, cling-g-g, and his voice was high and sharp, just like the voice of a buzz saw.

One day he walked out on the rocks over the water and began to talk to the black sea parrot, whose name is Epatka, and who sits erect on his carelessly built nest with one egg in it, and wears a great big bill made of red sealing wax. He has a long white quill pen stuck over each ear, and over his face is a white mask, so that nobody can know what kind of a face he has, and all you can see behind the mask is a pair of little foolish twinkling white glass eyes. What the two said to each other I don't know, but they did not talk very long, for in a few minutes when I came back to his house among the rocks Eichkao was gone, and there lay out on the bank a bill made of red sealing wax, a white mask, and two little white quill pens. There were a few bones and claws and some feathers, but they did not seem to belong to anything in particular, and the little foxes in the rocks went gurgle, gurgle, gurgle.

One day I lay down on the moss out by the old fox walk on the Mist Island, and Eichkao saw me there and thought I was some new kind of walrus which might be good to eat, and would feed all the little foxes for a month. So he ran around me in a circle, and then he ran around again, then again and again, always making the circle smaller, until finally the circle was so narrow that I could reach him with my hand. As he went around and around, all the time he looked at me with his cold, gray, selfish eye, and not one of all the beasts has an eye as cruel-cold as his. When he thought that he was near enough, he gave a snap with his jaws, and tried to bite out a morsel to take home to the little foxes; but all I offered him was a piece of rubber boot. And when I turned around to look at him he was running away as fast as he could, calling klin-n-g-g, klin-n-g, klin-n-g, like a scared buzz saw all the time as he went out of sight. And I think that he is running yet, while the little foxes still go gurgle, gurgle under the rocks.

III.-HOW THE RED FOX WENT HUNTING.

(_With acknowledgment to Mr. A. C. Bassett, of Menlo Park, California._)

Once on a time there was a great tall rabbit, the kind the miners call a "narrow-gauge mule"; but he was not a mule at all, and his real name was "Jack Rabbit." His home was in Montana, and he lived by the river they call the Silver Bow. He could run faster than any of the other beasts, and he went lickety-clip, lickety-clip, bounding over the tops of the sagebrush, for he had no brush of his own to carry.

And there was a red fox who lived on the Silver Bow, too, and he went hunting because he wanted rabbit for dinner. But while he could run very fast he could not bound over the tops of the sagebrush, for his own brush, which he always carried with him because he was so proud of it, would catch on the thorns of the other kinds of brush and so would keep him back.

So he sent for his cousin, the coyote, to come and help him. Now, the coyote lived out in the country by Emigrant Mountain. He was not proud at all, for he hadn't much of a brush, and nobody flattered him for his beauty. But for all that the coyote could run very fast, as he had Indian blood in him. The only trouble was that his hind feet ran faster than his fore feet. So he had to stop every little while and run sidewise to unkink himself and give his fore feet a chance to catch up.

When the coyote came up the rabbit was bounding along through the bushes, going around in a great circle so that he always came back to the same place, for that is the way of the rabbit-folk. So the fox lay low and hid his brush in the sage, and the coyote followed the rabbit around the circle. And he just kept up with the rabbit all the way, for the rabbit wasn't scared, and didn't run very fast. And when they had gone once around the circle the rabbit passed the hidden fox. Then the fox got up and chased him, and was only a few feet behind. And the coyote stopped and ran sidewise for a while to unkink himself, and then he lay down in the bushes and waited for the rabbit to come back. The rabbit was much scared when he saw the fox close behind him, so he ran and bounded very fast, and the fox kept falling behind because he had his long brush to carry. But he kept at it just the same, and when the rabbit came around the circle to where he started there was the coyote waiting for him. The rabbit had to make a great jump to get over the coyote's head. Then they went around again and the coyote kept close behind all the way, and the rabbit began to get tired. When the coyote's hind legs got tangled up then the fox was rested, and he took up the chase; and so they kept on, each one taking his turn, except the rabbit, who had to keep his own turn all the time.

When the race was over there was nobody there to see how they divided up what they caught. But I saw the coyote the next day, and he looked so very empty that I think that the red fox must have taken all the rabbit meat for himself. Most likely he left his cousin just the ears for his part, with a rabbit's foot to carry in his pocket for good luck.

GLACIAL GEOLOGY IN AMERICA.

BY PROF. DANIEL S. MARTIN.

Under this title the vice-president of Section E (Geology) of the American Association--Prof. Herman L. Fairchild, of the University of Rochester, New York--gave an admirable _résumé_ of the whole history, progress, and scope of the study of ice phenomena in North America, as the opening address before the section at the recent Boston meeting. Apart from the interest of the subject in itself considered, this address was a model of what such addresses should be. While strictly scientific, without the least attempt at rhetorical effect, it was at the same time so clear, so well arranged and so simple in language, that any intelligent auditor could enjoy it and grasp it, and carry away a distinct impression of the gradual development and present status of this great department of geological study. Professor Fairchild's choice of his subject was happy also in its fitness to the occasion, as covering almost exactly the half century of the life of the association, though going back indeed a few years further, into the period of the earlier society which developed into the association in 1848.

The great body of phenomena comprised under the term "drift," and the smoothed and scratched surfaces of rock, etc., had been by no means unnoticed by the early students of American geology, but they were attributed to violent and widespread water action, and were spoken of in general as "diluvial" formations. When the agency of ice began to be recognized, it was regarded as that of floating and stranding bergs; and this view for a long time contended with the theory of glacial action, even when the latter had been adopted and advocated by eminent students of the subject.

The first allusion to drifting ice as the agent of transportation of bowlders, etc., appears to have been made as early as 1825, by one Peter Dobson, of Connecticut, in a letter to Prof. Benjamin Silliman, of Yale College. Sir Roderick Murchison, who became the great champion of this view, credits Mr. Dobson's letter with giving him the first suggestion of it. Twelve years later, in 1837, T. A. Conrad made the earliest reference to land ice as the cause of our drift phenomena; he does this in very striking words when read in the light of the studies and determinations of later years, although of course imperfectly and vaguely.

Meanwhile, however, Agassiz and others had been working among the glaciers of the Alps, and their views as to a great period of former extension, in Europe and the British Isles, were finding some acceptance abroad. In this country, Prof. Edward Hitchcock, in his address as retiring president of the Association of American Geologists, in 1841, gave a broad and careful review of the drift phenomena in eastern North America, and referred to the work of Agassiz, Buckland, and Lyell with great interest, as having given him "a new geological sense" in observing these phenomena, and said, with prophetic foresight, "Henceforth, glacial action must form an important chapter in geology."

But the time was not ripe for the understanding and acceptance of the glacial theory as a later generation has come to know it. The studies of Agassiz and his _confrères_ had been among glaciers upon mountain slopes, and hence, while many of the drift phenomena were strikingly accounted for, others were not and could not be. So it came to pass that, while Professor Hitchcock and others in this country were strongly impressed, they were not satisfied, and held for years an uncertain position. The glacial indications conformed in some aspects to the theory, but not in others; the striæ and groovings, instead of following valleys, all had a general trend to the southward, and the bowlders were carried across great depressions and deposited upon heights. How could these conditions be due to glaciers? Could ice flow uphill, or move long distances over level areas? These and other phenomena, such as the peculiar distribution of drift material, in "drumlin" ridges and the like, had no explanation. Hence, notwithstanding President Hitchcock's utterances above quoted, and his similar Postscript on the subject of drift and moraines, appended in the same year to his volume on the Geology of Massachusetts, we find him in 1843, when again addressing the Association of Geologists, adopting a modified tone, dwelling upon these points of difficulty, and seeking a compromise view, which he called "glacio-aqueous." The great influence also of Murchison and Lyell had been thrown into the scale in favor of the iceberg theory, and this fact doubtless had much to do with the slow development of true conceptions. Lyell visited America in 1842, and was present at the American Geologists' meeting, advocating the floating-ice doctrine, to which most of our observers already leaned; and so the views of Agassiz and the glacial school had to wait for a decade before they found general acceptance or even audience.

This, we may note in passing, is but one marked instance out of many in the history of science, wherein the personal influence of eminent leaders has obstructed and retarded the advance of true knowledge. The whole recognition of the Cambrian system, as pre-Silurian and distinct, was suppressed and prevented for many years by Murchison's intense opposition to the views of Sedgwick. Similar facts might be cited in this country, did we care to mention names. Science can not claim, as is sometimes asserted, that it possesses or imparts any entire exemption from the influence of authority, and bestows complete independence from the tendency to "swear to the words of a master."

Of the New York geologists, Vanuxem alone, in his Geology of the Third District, 1842, inclined to the glacial theory; the others--Emmons, Mather, and Hall--advocated floating ice, the latter urging as a chief objection the absence of any great northern highlands from which glaciers could extend southward. Prof. Henry D. Rogers advocated De la Beche's view, of great catastrophic waves or _débacles_ of water and ice, produced by sudden uplifts of the floor of a circumpolar ocean, and sweeping southward with tremendous power over the middle latitudes. These views were presented by him in 1844, at the Washington meeting of the geologists, and are to us a most curious illustration of the old "cataclysmic" phase of geological conceptions.

Two years later Agassiz came to America, and at once set about studying the ice evidences here, first in the White Mountains and then around the Great Lakes. At the first meeting of the American Association, in 1848, he presented his views as to the identity of our phenomena with those studied by himself, Desor, and Guyot abroad. His views were not very warmly received, however, and he did not attempt their public presentation again for some years, turning his attention more to the field of zoölogy. In 1850, in a work on Lake Superior, he refers somewhat sharply to the prejudice that seemed to prevail in relation to this subject.

From this time, however, the aqueous theories began to be less strongly presented; and a new generation of geologists was coming on, largely under the training of Guyot and Agassiz, and more open to their observed results. C. B. Adams, in 1850, presented a view nearly akin to that adopted by Dana a few years later, of an elevation of the high northern latitudes, resulting in a southward-moving glacial sheet, and a subsequent depression connected with its retreat, to account for the stratified deposits. Professor Dana accepted this doctrine in his presidential address before the association in 1855, adding the "Terrace period" of partial re-elevation. From this time he became the leader of the American glacialists, and his great Manual, issued in 1862, carried these views into all the colleges of the country.

In 1857 Prof. Edward Hitchcock published an important treatise on Surface Geology, particularly of the Connecticut Valley, in the Smithsonian Contributions to Knowledge. In this paper he noted the distinction, so important and now so familiar, between local striæ and those with the general southward course of the "drift." Two years later his son, Prof. C. H. Hitchcock, extended this distinction widely over New England. In 1863 the report of progress of the Geological Survey of Canada gave an extended review of the surface geology, by Prof. Robert Bell, in which he fully adopted the glacial theory. Meantime, also, Professor Ramsay, in England, had abandoned the iceberg doctrine for that of glaciers.

In 1866 and 1867 important papers appeared by Charles Whittlesey, and one by Edward Hungerford; this last, read before the association, adopted the general views of Agassiz, with some important limitations now generally received. In the same year the revised edition of Dana's Manual gave yet fuller statement and wider diffusion to the generally accepted views as held to-day.

Professor Fairchild sums up this historical sketch as comprising four periods--viz., prior to 1841, undisputed reign of diluvial hypotheses; 1841 to 1848, suggestion and discussion of glacial hypotheses; 1849 to 1866, gradual acceptance of the latter view; from 1867 onward, development of glacial geology.

From this point, the address was occupied with consideration of the various aspects of the subject as studied and wrought out during the past twenty years by numerous observers. These are grouped under four main heads, each with various subdivisions--viz., (1) the ice sheet, as to its area, its thickness, its centers of dispersion, its migration of centers, etc.; (2) the ice period, as to its cause, its divisions, its duration, its distance in time; (3) the interpretation of special phenomena, such as moraines, drumlins, eskers, "kettles," and the like, valley drift, terraces, loess, etc.; and (4) existing glaciers, as discovered on our high mountains of the far West, and as studied in closer relation to the ancient phenomena in the great ice cap of Greenland and the immense glacier development in Alaska.

It is impossible to go into a detailed review of the numerous points of interest covered in this discussion. Suffice it to say that one who heard or who reads it finds an admirably clear and condensed account of all the problems and phenomena that have been and that are now encountered in the study of glacial geology on this continent, and of their gradual interpretation and solution by the combined labors of many students. The progress of knowledge over this wide field, advancing step by step, amid conflicting views and perplexing conditions, is beautifully shown, and leaves a very striking impression on the mind, of the difficulties and the successes of scientific research. Nor is Professor Fairchild disposed to claim too much or assert too strongly. He recognizes that, with all that has been met and mastered, there are still questions unsolved, and laurels to be won by others.

Among the facts brought out, a few may be briefly alluded to. The early abandonment of Agassiz's original view of a vast extension of the polar snow caps, and the recognition of separate centers of continental glaciation, now distinctly determined as three in number--a western, a central, and an eastern--the former being the earliest, and the others following in succession; the recognition by the Western geologists of the twofold character of the Glacial epoch, as also determined in western Europe, but less markedly traceable in our Eastern States, though now generally admitted; in close relation to this the determination of the line of the great terminal moraine, traced by successive observers from the Atlantic seaboard to Minnesota, and the subsequent recognition of an older, eroded, and fragmentary morainal "fringe," marking the line of the earlier ice sheet, somewhat beyond the later. With regard to the actual distance of the last glacial retreat, as expressed in years, Professor Fairchild is both cautious and frank. He notes the general consensus of recent observers toward a much shorter period than was formerly supposed--from five to ten or perhaps fifteen thousand years. At the same time, there are many elements of uncertainty involved, and the problem is by no means settled. The Niagara gorge, so long looked upon as a possible chronometer, grows more complicated as it is further studied; the rate of erosion has evidently varied much with the volume of water carried by the river; and this, in turn, has varied with the changes of level, and consequently of drainage routes, in the basin of the Great Lakes. There have been times when only the Erie waters flowed through the Niagara outlet, the upper lake drainage passing eastward independently, until a gradual northern rise of the land, which is proved to be still going on, turned the entire drainage into the present St. Clair route from Lake Huron into Lake Erie, and so through Niagara.

This point leads us to digress for a moment from the address under consideration to allude to a very interesting department of study that is now growing into prominence--to wit, the restoration of pre-glacial geography and hydrography, and the genesis of our existing river and lake systems throughout the northern part of the country. The discussions and results in regard to Niagara and the Great Lakes are somewhat familiar, but the work on the rivers and smaller lakes is not so widely known. Professor Fairchild himself has done much in relation to the "central lakes" of New York State; and one very interesting paper of this kind on The Development of the Ohio River was read before the section by Prof. William G. Light, of Granville, Ohio, besides many papers by others on similar topics.

The work done within a few years upon the glaciers of Arctic America has proved peculiarly fruitful in results. Here, again, the whole subject is reviewed historically, and the name and work of each observer are impartially noted. Much of the difficulty encountered by the glacial theory arose, as we have seen, from the fact that only mountain glaciers had been studied, so that many of the phenomena produced by continental ice could not be explained. Professor Fairchild says, as to this aspect: "More has been learned of the structure, behavior, and work of our ancient ice sheets by the study of the Alaskan glaciers during the last ten years, and especially by the study of the Greenland ice cap during the last four years, than by all the study of the Alpine glaciers for the seventy years since they have been observed." Prominent among those who have worked in this field are the names of Professors Chamberlain and Salisbury in Greenland, and Professors H. F. Reid and I. C. Russell in Alaska; other important contributors are Prof. W. P. Blake, the pioneer geologist in Alaska, 1867; Dall and Baker, who discovered and named the Malaspina Glacier in 1874; and John Muir, 1878, for whom the Muir Glacier was named; Wright, Baldwin, Schwatka, Libbey, and others, and Barton and Tarr in Greenland.

Professor Russell, in 1891, recognized and named a type of glacier that was before unknown. In his studies on the Malaspina he found a condition that does not occur, so far as yet observed, anywhere else than on the northwest coast of America; this is where a number of mountain glaciers debouch upon a low, flat coast plain, and unite to form a great sluggishly moving sheet of ice. This particular development he called the Piedmont type.

In closing his address, Professor Fairchild remarks that the word "theory," as applied to the glacial origin of the drift and its phenomena, may and should now be abandoned. The subject has passed beyond the stage of theory, and is as well understood and as clearly established as the volcanic origin of the cone of Vesuvius or the sedimentary origin of stratified rocks.

* * * * *

In the center of the artificial platforms or platform
mounds, characteristic of many of the ancient Peruvian
towns, Mr. Bandelier has observed features that recall
forcibly the New Mexican Indian custom of giving to each
inanimate object its heart. In some instances, says Mr. F.
W. Hodge, in his paper, round columns formed a kind of an
interior niche; in others, a small chamber contained urns or
jars with maize meal. A remarkable and very significant
feature was observed by the explorer in a partly ruined
mound at Chanchan. The core of this structure when opened
showed two well-preserved altars of adobe. In such interior
apartments, figurines of metal, clay, or wood are almost
invariably found; and the materially valuable finds made in
Peruvian ruins in earlier times came from the "heart" of one
or the other of the artificial elevations described.

MODERN STUDIES OF EARTHQUAKES.

BY GEORG GERALAND.

The investigation of earthquakes, seismology, has become in the present day an independent subject of scientific interest. In lands where earthquakes are frequent, as in Italy and Japan, seismic observations have been officially systematized over the whole country, with central and branch stations at which the work is never still. A net of seismic observations of all nations is being more and more closely woven over the whole earth, and there are yearly and monthly collations of observations of even the slightest shocks. Seismic literature is, therefore, nearly inexhaustible, and theory and praxis are in constant vogue; in short, seismics has grown to be a separate branch of science, and to demand independent treatment, calling for the energy and labor of many students. What gives it so great importance? What is the condition of our present knowledge and its history? What will be reached in the future through the competition of the nations? These questions possess a high scientific as well as culture-historical interest. We here attempt to answer them.

The first really scientific description of an earthquake--that of Lisbon--with its far-reaching accompanying phenomena, was the work of the greatest contemporary thinker, Kant, and it is not too much to say that his paper opened a new epoch in the knowledge of earthquakes. That terrible event and the extreme terror which it caused everywhere were followed in 1783 by the likewise extremely destructive earthquake of Calabria. The attention of the people was thus directed to this mysterious mighty activity of the earth, and was kept especially lively in Italy, the country of Europe most subject to earthquakes. The newly rising science of geology therefore found in the last third of the last century in these phenomena a problem of prominent importance. Geologists were the first to apply themselves to seismic studies, as the most widely current explanation of the phenomena is still a geological one. The scientific interest of the question prevailed over the practical. More attentive observation was given to earthquakes, the accounts of them scattered through the ancient chronicles were collated, and the already very numerous seismic notes of great earthquake manifestations--such as those by Hoff, Perry, Mallet, Volger, Fuchs, etc.--constituted a very important factor in the study. One of the earliest results of the inquiry was to show that directly perceptible earthquakes are not perceptible everywhere; that they are most common on the great upfoldings of the earth's crust on the mountain chains, such as the Andes, Alps, and Himalayas; and that, further, they are connected with the shores of the Pacific, the Antilles, and the Mediterranean, and with places also where great breaches and various disturbances are evident; that they are at home likewise in volcanoes; and that they are most frequent in the northern hemisphere, and when the earth is nearest to the sun. The descriptions of powerful shocks furnish us evidence of a double movement of the earth's crust--an alternate up-and-down vibration and an often very marked wave motion. The destruction which earthquake shocks and waves inflict on buildings, and the remarkably rapid and wide spread of the tremblings over the surface of the earth, have been very diligently inquired into; and when, in 1856, Naples and Calabria were visited by a great earthquake, an English investigator, Robert Mallet, made a full study of it, and believed that by comparing the direction of the rents in walls and buildings, which were assumed to correspond with that of the tremblings, he could identify the focus of the shocks in the earth's interior, and the course of the wave movement over its surface--a view which has long prevailed in seismology. Still more important was the work of the geologist Karl von Seebach, of Göttingen, on the great earthquake in central Germany, which kept the northern part of the plains of the upper Rhine, around Mayence, Grossgerau, and Darmstadt, disturbed for several years after 1869. Von Seebach's chief effort was to obtain the most exact data possible as to the time of the beginning of the shocks from as many places as possible, from which he might deduce the spot where the shocks began and were strongest, the epicenter which lay directly over the point in the earth's interior where the movement originated. From them he also deduced a series of localities where the shocks were simultaneous and of equal intensity, which could be connected by certain nearly circular lines called _homoseists_. As the distance of these from the epicenter increases, the undulations take place later and are weaker, and facts may be thus furnished from the velocity of propagation of the shocks can be computed. The observations are also important because von Seebach undertook through a simple mathematical calculation to determine from them the situation of the forces of the subterranean point where the undulations originated.

With these investigations, the process of annihilating time and space by steam and the applications of electricity was also going on. By the effect of this great event, the conditions of earthquake investigation were revolutionized. A comparative study of the phenomena, fundamental and essential to a science of seismology, on the basis of material furnished from all the regions of the earth, was rendered possible. An earthquake service was organized in Japan, by J. Milne, of England; one had already been organized for a considerable time in Italy, and the results obtained at the two places of observation so widely separated corresponded. Japanese, Indian, and American earthquakes could be simultaneously studied in Italy, Russia, Germany, and England; and thus a new, hitherto undeveloped field was gained, the scope of which has already extended far beyond its merely geological aspect.

This could have happened only through another advance that has been made in our century, which has first rendered a real seismology, a scientific knowledge of the seismic conditions of the earth, possible through the immense development of technics, by which a system of instrumental observation of earthquakes was established. Only through this could the acquisitions of recent times be utilized. While formerly observations were macroscopic and touched only earthquakes that could be directly felt, they now cover essentially microscopic tremors of the earth's crust, of less than a thousandth of a millimetre, that are wholly imperceptible to human senses; and we can read them, enlarged at our pleasure, on our photographically registering seismometers. We already had instruments which correctly indicated the time of the beginning and possibly the direction of a shock; but we needed and have invented new instruments--various sorts of horizontal and vertical pendulums--for the observation and representation of the whole course of the movement. The vertical indicating instruments are much used in Italy, and the horizontal ones almost exclusively in England, Japan, and Germany. The horizontal pendulum was invented in Germany in 1832 by Hengler, adapted to scientific use by Professor Zöllner, of Leipsic, and afterward applied in that form by English, German, and other observers. The most complete shape and the one best adapted to extremely delicate seismic observations was given to it by the late German astronomer and geographer Dr. Ernst von Rebeur Paschnitz, of Merseburg. Having undergone a few small changes, fixed in a threefold combination it serves as our most sensitive and accurate seismometer. Its movements and its very exact time markings are photographically represented. The pendulum box is only forty centimetres in diameter. In consequence of its convenience and cheapness, its self-action and its serviceability, it is becoming adopted more and more generally as an international instrument.

Microseismic investigation and its wide extension over the earth have raised seismology another step during the last twenty years, so that it may be said that really exact seismic research began with it. Modern seismology has confirmed many of the older results, such as the localization of earthquakes on the shores of the Pacific, the Mediterranean and in the mountain chains of the earth, and also the importance of homoseists and the epicenter. It has, on the other hand, greatly modified the former estimates of the velocity of propagation of the shocks. It has cast much doubt on speculations as to the seasons in which earthquakes are more or less frequent; and it has demonstrated the inadequacy of former methods of determining the central focus. It has furthermore brought us much that is new. First is the momentous fact that the earth's crust is never at rest; that it undergoes a multitude of very diversified movements besides those of the earthquake. Thus a periodical swelling, a flood wave, is produced by the attraction of the moon; and other heavings are induced by the daily and annual course of the sun's heat. But such movements and other similar ones do not come within the scope of this article.

Real earthquakes, or movements that originate in the depths of the earth, also appear in very different forms. First are the directly perceptible shocks, from the powerful ones that create great disturbances to the merely local ones often hardly remarked. Of the immediate workings of these shocks, microscopic instruments have taught us nothing essentially new. But very many macroscopic movements, often continuing for several hours, but which are not felt, have been revealed, that have been shown in many instances to be distant effects of other strong earthquakes; effects which are sometimes propagated over the whole surface of the earth. There is, furthermore, another series of movements, only partly explained as yet, of a peculiar sort: first, small, quickly passing disturbances, which appear in the photographic reproductions of the curves as larger or smaller knots, and which are regarded with great probability as distant effects of minor seismic movements most likely imperceptible anywhere. They can not be local earthquakes, for they give entirely different curves. There also appear, with considerable regularity, at certain seasons of the year, very slow movements of the ground, called pulsations; and finally the multitude of vibrations called tremors, which assume various forms. Sometimes they come as forerunners, accompaniments, or followers in close association with those great disturbances that originate in distant earthquakes; sometimes as shocks of minute intensity in separate groups, which it has not yet been possible to account for; and in other cases they are traced to the shaking of the ground by the wind. It is hardly necessary to observe that the seismic apparatus should be most carefully guarded against disturbance by the movements of trade, wagons, etc., so that the problem shall not be complicated by them.

The theory of the nature of earthquake shocks, their transmission and their velocity, has been set in a new light by the labors of Augustus Smith, of Stuttgart. From some calculations of their velocity made by G. von Nebeur, it is found that the earthquake of April 17, 1889, in Tokio, Japan, was perceived in Potsdam, Prussia, nine thousand kilometres distant, in thirteen minutes; that of October 27, 1894, in Santiago, Chili, in Rome, eleven thousand five hundred kilometres distant, in seventeen minutes, and in Charkow, Russia, two thousand kilometres from Rome, between one and two minutes later. It reached Tokio at the same time, after a transit of seventeen thousand four hundred kilometres.

Still another task of modern seismology is the investigation of earthquakes at sea, or seismic movements of the bottom of the ocean, and the manner in which they are propagated through the water, of which a very fine cartographic representation has been published by Dr. C. Rudolph, of Strasburg.

The question of the origin of earthquakes stands in constant connection with this external development of seismology. It is significant and remarkable that the answers to it, though they may be given differently from different scientific points of view, are always consistent in one fact, that earthquakes are a phenomenon of the whole earth. Some of the investigators seek to explain them, aside from those that occur in volcanic regions, as a part of the great changes in the earth's crust which have taken place during the last geological epoch, and are still, perhaps, taking place; others find their seat and cause in the unstable condition of the interior of the earth, beneath its solid and red-hot envelope. The former explanation, the older and heretofore the prevalent one, is called the tectonic theory, because it is based, leaving out volcanic earthquakes, on the structure of the earth's crust; the second, which is gaining ground, and requires no separate explanation for volcanic earthquakes, may be called, reviving an expression used by L. Fr. Naumann, of Leipsic, the Plutonic theory, because it goes down into the unexplored depths of the earth. If seismic manifestations depend upon the action of the whole earth, a single explanatory principle, as is always the case with great natural phenomena, is not sufficient, and tectonic as well as Plutonic earthquakes must be recognized, and the reverse.

The tectonic theory is of geological origin, and properly supplanted the older Plutonic theory of Humboldt, which was only an unverified supposition. As a whole it was first worked out by Otto Volger in 1858, after various similar hypotheses had been set forth by other investigators. He was confirmed by the independent researches of Rudolf Hoernes, Edouard Suess, and most of the German, French, and English seismologists.

Their theory supposes that there are large hollow spaces in the crust of the earth, into which immense falls of material take place, and that these are the cause of a part of the earthquakes; that the crust of the earth is often and variously disturbed in consequence of the constant contraction dependent upon the cooling of the globe. It is broken up into separate masses which in their turn are dislocated horizontally or vertically; is lifted up and folded into immense mountain ranges, the arches of which, breaking, may again suffer dislocation. Thus continuous action in movement of masses and foldings is constantly going on in the earth. Edouard Suess, the distinguished Austrian geologist, has indeed constituted a special earthquake type to correspond with this type of mountain formation. Since, in consequence of this condition, tension is present everywhere in the crust of the earth, it may come to pass that it shall be relieved by a distant earthquake, and another earthquake, which may be called a relay or transmission earthquake, be produced thereby. Hence we have, besides the volcanic, the landfall, the tectonic (in the strict sense), and the transmission earthquakes. The sources of earthquake force lie, then, according to this theory, in the incompleteness of the earth's crust, the effects of gravity, and the earth's loss of heat.

And is the supposition not very probable? Do we not see similar processes going on over the whole earth, in the shape of earthquakes, landslides, fissures, subsidences of land, and the like? And as the Alps were lifted up, and the plain of the Rhine was depressed between the Vosges and the Black Forest, may not mightier dislocations, breaches, and destruction occur? Why may not the processes which took place in the earlier epochs of the earth's history and were so powerful in the more recent Tertiary be still going on? All this seems so plausible that, with a few exceptions, the theory has been almost universally agreed in.

I briefly mention here Falb's theory, which, accepting the earlier views, ascribes earthquakes to periodical swellings of the fiery fluid interior of the earth, only because of the effect it has had on the public in connection with some wholly unscientific predictions. More worthy of consideration is the theory of Daubrée, the late distinguished master of French and especially Alsatian geology, who did not attribute the similar phenomena of volcanic and nonvolcanic earthquakes to different causes, but maintained that all earthquakes were produced by superheated steam issuing from surface waters. But this theory needs no refutation. There are, however, some serious objections to the tectonic theory of earthquakes, plausible as it may seem. In order to weigh them as we ought, we must as briefly as possible construct a picture of the constitution of the earth's interior.

The average distance from the earth's surface to its center is sixty-three hundred and seventy kilometres. The temperature of the earth increases with the depth, at the rate, on a moderate estimate, of about one degree centigrade for every forty metres. Hence, at a depth of one thousand kilometres we would have a temperature of 25,000° C.; even if we call it only 15,000°, we should expect to find there only gases, and those in a simple state, for with that heat all the compound gases would be dissociated. The zone of fluidity for all rocks lies at a depth of about one hundred kilometres, where the temperature is 2,500° C. While the crust of the earth is between 2.5 and three times as heavy as distilled water at 4° C., its specific gravity rises toward the center of the earth to more than eleven, or about fourfold. Iron has a specific gravity of 7.8, or about threefold that of the crust of the earth; but the specific gravity of the earth at the greatest depth is considerably higher than this. Hence must arise an enormous pressure, steadily increasing toward the center, where, according to the English geophysicist, the Rev. Osmond Fisher, it reaches about three million atmospheres to the English square inch. It results from these conditions that with the enormous pressure and heat, and specific gravity, the interior of the earth consists of dissociated gases compressed to great rigidity, which exert an immense counter-pressure--for their tendency is always to expand. They pass out continuously into a zone of fluid matter, and this again is held by the pressure of the interior gases in a like compact condition. Thus a very high pressure still prevails in the lower parts of the solid crust of the earth, which is so high that even the most solid rocks there are in a latent plastic condition--that is, they behave toward different forces like plastic clay, and like it can be deformed without breaking. Rents, slides, caves, and clefts are out of the question there; things of that kind can exist only in the upper strata.

This fact constitutes a very strong objection to the tectonic theory of earthquakes, and thus the very depths of the earth speak against it. We have already mentioned that K. von Seebach estimated the depth of the earthquake focus from the movements of the waves, and found it not very great. But his estimates, as Prof. August Schmidt has shown, rest upon physically incorrect premises; according to Schmidt's more correct calculation, the center of the Charleston earthquake of 1886 lay at a depth of one hundred and twenty kilometres, where there can be no question of tectonic movements, because general fluidity is reached at one hundred kilometres. Further, the earthquake at Lisbon, if the tectonic theory is valid, might, taking the character of the region into consideration, have been occasioned by a slide. But how large must the plunging mass, how deep the plunge or slide have been to produce such shocks as destroyed Lisbon and shook Europe to beyond Bohemia! Where can we find room in the closely compressed interior of the earth for such irruptions? Even if such a sudden sinking had left no trace in the interior, it should have left its marks on the surface. Mr. John Milne counts up not less than 8,331 considerable earthquake shocks in Japan between 1885 and 1892; Julius Schmidt, former director of the observatory in Athens, enumerated three hundred severe and dangerous and fifty thousand light shocks for Phocis alone between 1870 and 1873, of which not a trace of land changes or depressions can be perceived, aside from superficial avalanches (on Parnassus, for example) and subsidence of meadows and other spongy soil, like the famous depression of the Molo at Lisbon.

All this speaks so emphatically against the tectonic origin of earthquakes that it can not be considered as a general cause. Even the mighty disturbances and shocks of the times when such ranges as the Alps and Himalayas were lifted up can prove nothing for the present time; for the conditions, the mechanical work and acting forces, of the earth were quite different, and the latter much greater and more acute than in our time, as the number and magnitude of the volcanoes of those ages show, before which ours are almost as nothing. We have no adequate comprehension of the way that mechanical work was done. A depression like that of the plain of the Rhine could certainly not have taken place without severe earthquakes; but we do not know how they may have come to pass, for we have nothing analogous to them. The upper strata of the earth's crust are broken up, fissured, and cavernous; hence purely local minor earthquakes may undoubtedly be produced by cavings-in, landslides, and settlings of small extent. But this explanation, in view of the nature of the crust, is not possible for strong earthquakes, even in the upper layers, which send their waves far over the land; their origin must be, almost of necessity, in the greater deeps beneath the crust, far down where the immense gas globe of the interior is constantly forcing its way into the fluid band, and this into the solid stone; in those zones of changing conditions a mighty movement must be incessantly prevailing. The pressure upon the gases of the interior diminishes here, and the excessive temperature as well. This can not take place without changes. Temperature and pressure now fall, now rise again, but continue very high through it all. The dissociated gases unite and separate again, and most violent explosions are infallibly produced thereby. Water exists in the interior in immense masses, and that not solely in consequence of percolation from the surface. Vapor at very high pressure separates into its elements--hydrogen and oxygen--the reunion of which ensues with violent explosions, similar to our gas explosions, which must be very numerous in the interior of the earth, and accompanied with great development of force. The principal effect of such explosions is, of course, against the cooler and more weakly resisting sides, and therefore not toward the interior but toward the crust and the weakest parts of it, toward the rupture lines of the zones of disturbance, the synclinals. Such attacks, striking the earth's crust from within, occasion most earthquakes, especially violent, destructive, deep-seated outbursts like those of Lisbon and Charleston. The relation of the seismic and the volcanic phenomena is clearly to be seen.

One series of seismic phenomena remains to be explained--the lighter undulations, the tremors, and the remarkable irregularity of the movements of the ground. The indications of the vertical pendulum apparatus which represent these movements form an inextricable tangle of lines running over and crossing one another. The late Japanese professor of seismology, Sekiya, prepared an enlarged model of the tracings of the seismic movements of a point of the earth's surface, which has been much copied. It represents an extremely confusing vibration of the lines.

Now we have to confront a very important fact which adds much to the difficulty of seismic research. We never feel and observe the earthquake shocks themselves, never directly in their simplicity or multiplicity, but only the wave movements that are sent out from them in the elastic crust of the earth. These, however multifold their origin, proceed in an immense spherical wave which moves in more or less numerous repetitions through the earth's interior. It is this shaking of the earth by the spherical waves that our instruments represent as earthquakes. We can not include as the earth's crust the surface of the earth on which we live, and which consists of loose materials disintegrated by weathering, breaking, and numerous causes, but the solid crust, often lying at a considerable distance beneath us, which bears these materials, and from which the spherical waves emerge. As the waves of the sea, beating upon the coast, are turned, split up, divided, thrown up, etc., in their surging, so surge, too, the seismic waves upon the disintegrated surface of shingle, pebbles, broken rocks, sand, and earth, in clefts and gorges. We thus never observe the original spherical waves, but only their fragmentary derivative forms, their resolution into numerous single waves which come to us diverted into the most various directions. It is thus most plainly shown that Mallet's effort to determine the center and origin of the earthquake from the direction of the shock was futile. We can only draw scientific conclusions respecting the time of beginning, the duration, and force of the movement. It is thus evident that many of the tremors (not all, by any means) originate in this division; that a fixed point of the earth's surface must describe a very complicated path in so intricate a wave movement; that the division is less marked on firm ground than on loose; that the former, in consequence of the more evenly protracted movement, is less dangerous than the latter; and that multiplied waves interfere, overlay, weaken, or strengthen one another just as water waves do. Thus are explained the earthquake bridges or spots which always remain unmoved through repeated earthquakes, either because they are firmer, or because the progress of the waves is arrested at them by interference.

The sounds, too, which so frequently accompany earthquakes are likewise simply results of this division of the waves and their escape into the air, for we perceive wave motions in the air as sound. The admirable delicacy of our sense of hearing is here manifested, for seismic movements are not rarely perceptible, or heard, as air waves, which we can not perceive as movements of the ground. Earthquake thunder is caused, like storm thunder, by shocks to the air, of which we hear the nearest and latest first, and the farthest and earliest last. The different tone shades of the earthquake sound depend upon their various sources, as from small, sharp fragments, clinking, rattling, and humming; from sand and earth, dull rumbling; from trees, whistling, etc. The echo in ravines not rarely operates to add strength to them. Earthquake sounds that seem to come out of the air from above are caused by earthquake waves reaching us by way of trees, houses, etc.; the different directions and degrees of force which they seem to indicate in different houses or in different rooms of the same house are explainable by the different elasticity conditions of the houses and rooms. But not the most insignificant conclusion can be drawn from these sounds concerning the nature and causes of earthquakes. It is important to emphasize this fact, for errors have often originated in conclusions drawn from such things.--_Translated for the Popular Science Monthly from the Deutsche Rundschau._

* * * * *

Examples of a race of curiously protectively colored mice
which inhabit the sandy island, the North Bull, in the Bay
of Dublin, were exhibited by Dr. H. Lyster Jameson in the
Zoölogical Section of the British Association. A
considerable percentage of them were distinctly lighter hued
than the ancestral type of house mouse, though every
possible gradation occurred between the typical house mouse
and the palest examples. The speaker regarded the marked
predominance of sand-colored specimens as due to the action
of natural selection. The hawks and owls which frequent the
island, and are the only enemies the mice have to compete
against, most easily capture the darkest examples, or those
that contrast most strongly with the color of the sand. Thus
a protectively colored race is becoming established. The
island came into existence only about a hundred years ago.
Consequently it is possible to fix a time limit within which
the sandy-colored race has been evolved. Its evolution also,
as Professor Poulton observed in his comment on Dr.
Jameson's paper, gives additional evidence to that afforded
by the shore crabs described by Professor Weldon in his
presidential address to the section, that the transmutation
of species is not necessarily so slow as to be
indiscernible.

A SHORT HISTORY OF SCIENTIFIC INSTRUCTION[33]

BY J. NORMAN LOCKYER, K. C. B., F. R. S.

The two addresses by my colleagues, Professors Judd and Roberts-Austen, have drawn attention to the general history of our college and the details of one part of our organization. I propose to deal with another part, the consideration of which is of very great importance at the present time, for we are in one of those educational movements which spring up from time to time and mold the progress of civilization. The question of a teaching university in the largest city in the world, secondary education, and so-called technical education are now occupying men's minds.

At the beginning it is imperative that I should call your attention to the fact that the stern necessities of the human race have been the origin of all branches of science and learning; that all so-called educational movements have been based upon the actual requirements of the time. There has never been an educational movement for learning's sake; but of course there have always been studies and students apart from any of those general movements to which I am calling attention; still we have to come down to the times of Louis Quatorze before the study of the useless, the _même inutile_, was recognized as a matter of national concern.

It is perhaps the more necessary to insist upon stern necessity as being the origin of learning, because it is so difficult for us now to put ourselves in the place of those early representatives of our race that had to face the problems of life among conditionings of which they were profoundly ignorant: when night meant death; when there was no certainty that the sun would rise on the morrow; when the growth of a plant from seed was unrecognized; when a yearly return of seasons might as well be a miracle as a proof of a settled order of phenomena; when, finally, neither cause nor effect had been traced in the operations of Nature.

It is doubtless in consequence of this difficulty that some of the early races have been credited by some authors with a special love of abstract science, of science for its own sake; so that this, and not stern necessity, was the motive of their inquiries. Thus we have been told that the Chaldeans differed from the other early races in having a predilection for astronomy, another determining factor being that the vast plains in that country provided them with a perfect horizon.