Popular Science Monthly/Volume 22/November 1882/Popular Miscellany

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The Glacial Moraine in Pennsylvania.—Professor H. C. Lewis read a paper before the American Association concerning the results of his efforts to trace the great terminal moraine marking the southern limit of the North American ice-sheet across Pennsylvania. The moraine had already been traced from Cape Cod across the Elizabeth Islands, Rhode Island, Long Island, and New Jersey, and across Ohio, Indiana, Illinois, Wisconsin, Minnesota, and Dakota, into the Saskatchewan region of the Dominion, but had not been remarked in Pennsylvania. Professor Lewis had found it entering the State near Easton, whence he traced it up and down to Potter County, and thence into New York State. Then it shortly turns to the southwest, enters Pennsylvania again, and passes into Ohio. It was thus traced for four hundred miles. It begins at a height of 240 feet above the sea, reaches 2,480 feet in Potter County at the great divide between the waters that flow into the Atlantic and those that flow into the Gulf of Mexico; is 2,000 feet high at the extreme north point near Olean, New York, and is 800 feet high in Eastern Ohio, at the end of the portion examined. At the Delaware Water-Gap the ice did not pass down the valley, but across it. The Pocono Mountain was a promontory projecting northwardly into the ice-sheet. The glacial covering does not seem to have formed tongues pushing down in river-valleys, as is the case with modern glacier systems. Bowlders of labradorite and other crystalline rocks from the Adirondack and Ontario highlands were found all along the moraine line. In the discussion that followed the reading of his paper, Mr. Lewis asked Principal Dawson, as a leading opponent of the glacial theory, to explain certain facts according to his hypothesis of floating ice-fields. Principal Dawson replied, asserting that a continental ice-field in Northern America large enough to supply food for the alleged glacier was a physical impossibility, because, on account of the distance of this territory from open seas, the climate would be too dry for any such accumulation of snows. It was possible, however, that there might have been a river or a glacier which produced the moraine in that part of the country particularly referred to; but he could account for moraines in another way. Whenever a cold current infringes upon a warm current, it forms a moraine; and this is taking place in the region of the Gulf Stream. He himself owned a piece of land on the coast of the lower St. Lawrence, on which a very good moraine was now in course of formation.

The Gulf Stream.—The work of deep-sea soundings and determination of temperatures has been carried on continuously in the steamer Blake in the Gulf Stream for several years. The paper on the subject read by Commander Bartlett, at the recent meeting of the American Association, describes what was done in 1881 and 1882 under the direction of Professor Hilgard. The Gulf Stream does not run in a basin, nor is it divided into cold and warm alternate layers. The deepest bottom between Florida and the Bahama Banks is 459 fathoms below the surface, and the current runs from three to eight knots an hour, with a temperature of from 80° to 83° Fahr. A wide plateau exists off Florida, gradually narrowing as it goes north. Off the Carolinas it is forty or fifty miles wide. Near Savannah soundings were made at 1,840 fathoms. The 500 and 1,000 fathom lines are very close to the 100 fathom line north of Cape Hatteras and up to the Georges Bank off Massachusetts. Directly beneath the Gulf Stream is a hard coral limestone, with no loose material. The globigerina begins to appear at Charleston going north, and increases in amount. The cold water from the Arctic region flows inside the Gulf Stream off the American coast, and beneath it, falling down a depth of a thousand fathoms. The Bahama section showed a temperature of 44° at 459 fathoms, and washes in through the Windward Islands, south of Cuba, rather than through the Florida Channel. Outside the ridge, between Cuba and Hayti, the temperature descended to 3612°, but the coldest found in the Gulf of Mexico was 3912° down to 3,400 fathoms. There is no Gulf Stream in the Gulf of Mexico.

Indian Marriage Laws.—A paper on this subject, read by the Rev. J. Owen Dorsey before the American Association, notices some remarkable customs in relation to marriage and kinship as prevailing among the Dhegitha Indians, particularly the Omahas and Poncas.

When a tribe is hunting it camps, by gentes or nations, in a circle, each gens bearing the name of some animal. All the members of one gens are relatives, and marriage between members of one gens is absolutely forbidden. Membership in a gens is by descent in the male line, not in the female. The relations of a man are denoted by colors; for example—black, grand-father or grandmother; blue, father or mother. His connections are denoted by mixed colors, such as a pink head and skirt, with light-blue triangle on the body, for sister-in-law. A man can marry his brother's widow, and her children call him father even before their father's death. His sister's children are only nephews and nieces. His mother's sister is always called mother for the same reason, and even his paternal grandfather's brother's son is his father. These, and many other distinctions, show that the terms of relationship are far more numerous and complicated with the Omahas than with us. A man may marry any woman belonging to another gens, whether connected with him or not; though marriage into his mother's gens is also forbidden. A man can not marry any woman to whom he is related by the ceremony of the calumet-dance. Sometimes a man may take the children of his deceased brother without their mother herself. Sometimes the dying husband, knowing that his male kindred are bad, tells his wife to marry out of his gens. If a widower remains single for two, three, or four years, he must remain so for ever. Widows, however, must wait four years before remarrying. The same system prevails among the Iowas, Otos, and Missouris.

Hygiene in House-Walls.—Mr. T. R. Baker, in a paper read before the American Association, "On the Permeability of the Linings of House-Walls to Air," assumed that ordinary wall-paper made the walls of dwellings nearly air-tight. Hygienically considered, the walls of a house should be porous, like our clothing, so that our bodies can have through them, as also through our clothing, free intercourse with the external air. Compact wall linings, even if their minute pores are open, greatly interfere with this intercourse; but if their pores are closed with water, as when the walls are damp, it is almost completely cut off; and such linings increase the dampness of walls by preventing their drying in wet weather. The prolonged dampness also prolongs other evils produced by damp walls; therefore wallpapers and their substitutes should be condemned, and the old-fashioned whitewashed walls commended.

Succession of North American Flora.—Professor J. S. Newberry, describing the evolution of the North American flora, at the meeting of the American Association, said that the first flora was that indicated by the plumbago of the Laurentian formation. The kind of vegetation can not be determined. The second is in the Silurian. The evidence of actual vegetable origin is, however, defective; the objects may be corals rather than land-plants. The third flora is in the Upper Silurian; the fourth is in the Devonian. Two hundred species at least are described by Dr. Dawson, consisting of conifers, ferns, sigillarids, cycads, lycopods, etc. Several interesting varieties of this Devonian flora have recently been discovered in Ohio. The fifth flora is the Carbonaceous, the sixth the Liassic, and the seventh the Cretaceous, a flora containing broad-leaved plants of the angiosperms, which, with slight change, has continued to the present time. The Jurassic group is plainly cretaceous, and is entirely unlike the Tertiary. Not a single plant can be identified with any of the Old World tertiary flora. The various tertiary floras of the Rocky Mountains occur in the dried-up basins of old lakes. When the glacial period came on, the trees were entirely destroyed over the northern part of the continent. After the melting of the ice, the present flora made its appearance.

The Depression of our Atlantic Coast.—Professor George H. Cook, State Geologist of New Jersey, has presented, in a paper which he has read before the American Association, a large array of evidence showing that the Atlantic coast of our continent is gradually subsiding. It consists largely of the testimony afforded by the remains of ancient forests, composed for a considerable part of upland growths, which have been found in various places from the Carolinas to Greenland, either submerged at high water or at depths beneath the surface lower than the high-water mark of the neighboring coast, and at these places sometimes with present or former swamps over them. Sunken forests possessing some or other of these characteristics are mentioned as existing in the Carolinas and Georgia, where they were noticed by Bartram in 1773, Lyell in 1845, Professor Tuorney, of South Carolina, in 1846, and in Albermarle Sound, North Carolina, by Dr. Emmons. General Cutts, of the Coast Survey, has observed timber in the place of its growth several feet below the level of tide-water along the shores of Chesapeake Bay, in Virginia. The coast of New Jersey is marked by the occurrence of timber and stumps below the present tide-level in the marshes which border the State from the head of Delaware Bay to Cape May, and thence to the mouth of the Hudson. A marked example of yellow-pine stumps may be observed in the banks of the canal which connects South River at Washington with the Raritan. Similar submerged forests on Long Island have been described by Elias Lewis, Jr., in "The Popular Science Monthly." In Massachusetts, they have been observed at Nantucket, Holmes's Hole, Yarmouth, and Provincetown; in New Hampshire, at Eye Beach; in Maine, at Portland; and at the head of the Bay of Fundy in Nova Scotia. Other evidences are afforded by the subsidence of human structures since the period of settlement; in the flooding of farm-lands that have had to be abandoned, the submersion of boat-stakes, and the approach of the sea to buildings on the shore. Instances of this kind are observable at Southampton, Long Island, Barnegat, New Jersey, the shores of Delaware Bay, and on the west coast of Greenland. The encroachments of the sea at Long Branch and the changes going on at Sandy Hook are public facts. Professor Cook believes that the change thus marked is common to the whole northern hemisphere. It is certainly taking place in parts of Sweden. Some doubt has been thrown upon the theory of a subsidence from the fact that sea-shells and buried timber, both of kinds now living, have been found in deposits a few feet above the present sea-level. These instances are, however, regarded as belonging to another era than the present period of depression, and are distinguished by several important differences of features from those now under consideration. Professor Cook thinks that they belong to a previous period of depression; that the present period may not have been going on for more than five hundred or a thousand years, and that in the one which preceded it the surface of the upland was ten feet or more nearer the sea-level than it now is. He adds: "A careful study of the numerous cases like this will satisfactorily prove that there have been other periods of alternate depression and elevation in comparatively recent times, the phenomena of which are so nearly alike that they are very commonly confounded with each other. And, when they are clearly distinguished, it will be found that the rise or the depression is one common to our whole coast, and probably to the whole northern hemisphere."

The Esquimaux.—Dr. John Rae, in giving an account of his Arctic explorations before the American Association at its recent meeting, spoke of the Esquimaux as a generous and polite people, who had carefully preserved the tradition of events that happened twenty years ago. They believe they came from the West; and they seem to Dr. Rae physically like the Chinese. They build their huts and boats in a similar way with the Siberian natives, but appear very short in stature on account of the shortness of their legs. Dr. Flam, of London, had said that the skeleton of an Esquimau in his museum had thirty-five vertebrœ, or one more than the average number. They are not to be regarded as gluttonous, for the large quantities of meat they consume seem to be required by the climate.

Apparent Size of Magnified Objects.—Professor W. H. Brewer reported to the American Association concerning some experiments he had made upon the estimation by different persons of the size of images of objects seen through the microscope. More than one hundred persons, of all ages, classes, and occupations, gave very many different estimates. A common louse was used as the test-object, and the magnified image was projected at ten inches. By far the larger number of persons underestimated the size value theoretically given the image by scientific microscopists, which was about 4.66 inches. Two estimates were of only an inch; several were of more than a foot. One student likened the figure to a cockroach, another to a lobster. Mechanics and artisans generally overestimate. A draughtsman, who was accustomed to measure and draw all his work, after careful examination said the image was at least five feet long! A professor of physics said he could make the image look of any size he wished.

Fossil Human Foot-prints in Nevada.—Several communications have lately been made to the California Academy of Sciences respecting what seem to be foot-prints of men which have been discovered in a sandstone hill in the yard of the State Prison at Carson City, Nevada. The hill is about sixty feet high, and stands at an elevation of 4,592 feet above the sea. It appears to have been formed by the deposition and drifting of sand upon what was the bed of an ancient lake. A surface of about three quarters of an acre has been cleared by quarrying to a depth of from fifteen to thirty feet, and down to the layer of arenaceous shale beneath the sandstone, which is supposed to represent the bottom of the lake. The tracks are in this shale. According to the description of Dr. Harkness, they are accompanied by the tracks of several animals—the mammoth, the deer, the wolf, the horse, and some birds—and are in six series of from eight to seventeen foot-prints each, in regular order, and each showing more or less plainly the imprint of a sandal. The first series, consisting of sixteen tracks, "were evidently made in a layer of sediment of, perhaps, two inches in depth, for below this layer we find the compact sandstone. In each instance the mud had been raised by the pressure of the foot into a ridge which entirely surrounded it." No single impression affords complete evidence that it was produced by a sandal," but when we study them as a whole," says Dr. Harkness, "we find that what is wanting in one is furnished by others which follow." These tracks measure nineteen inches in length, by eight inches in breadth at the ball and six inches at the heel. The average length of the stride is two feet three inches. The distance between the feet, or the straddle, is eighteen inches. A second series of tracks was observed, made by an individual who was walking in deeper mud, which clung to and closed in and upon the foot. In another part of the area are four other series, at a level a few inches lower than those of the first series, smaller, and possibly made by moccasins. The toes of the tracks of the first series turned outward; "number two," says Mr. Gibbes, curator of mineralogy, in his account, "toed the mark, and walked as straight as a surveyor running a line. Series number three presents more irregular steps with toes turned out, possibly those of a woman bearing a heavy burden." Within the same area are the immense tracks of a mammoth, quite as plainly marked as the others, and, in another part of it, marks which Engineer Scupham, of the Central Pacific Railroad, describes as "confused tracks of a man and some large animal. Only two or three steps of the man are distinct; then the confusion that appears to mark the struggle, and then the impression where a great body has fallen. After the struggle the great crane has waded about over the spot; its tracks winding in and out as if it had been avoiding with care the deep impressions made by the combatants, till at last, stumbling into one, it rises in startled fright. Farther to the north are many human tracks, all telling different stories of the track-makers." The question whether the foot-prints are really those of men is under discussion. Their size and the width of the straddle are against them. Professor Harkness suggests, however, that the sandal is not necessarily much larger than would be made to protect the side, as well as the heel and toe, of a foot twelve or thirteen inches long; and persons laboring in heavy mud would tend to make a wide straddle. The stride corresponds well with that of a man. Professor Joseph Le Conte, who also has examined the tracks, has expressed the opinion to the Academy that "no one who studies them can fail to observe their remarkable general resemblance to human tracks." He thought they might have been made by a human foot inclosed in a rawhide sandal much larger, externally, than the foot. He knew of no animal but a biped that could make such tracks; and this was possible for a man with sandals on to do. As a judicial mind, he desired to hold his final scientifically expressed opinion in reserve, awaiting further testimony. Several fossils have been found in the formation—tusks and teeth of elephants and horses, vegetable remains, and the freshwater shells anadonta and physa. It is difficult to determine the exact age of the strata, but they are generally agreed to be cither Quaternary or Pliocene.

The Infant Giant Jaw-Bone of Stramberg.—The Congress of Austrian Archæologists, recently in session at Salzburg, was the scene of an interesting discussion of the human jaw-bone, m which the proportions of a giant were found associated with the teeth of a child, which was dug out, at Stramberg, in Moravia, from under a formation containing bones of the reindeer, snow-owl, cave-bear, and other Arctic animals. Professor Schaffhausen maintained that the jaw was one of a child, of between eight and nine years old, in which the change of teeth was going on. The incisors had already changed, and an eye-tooth and the premolars were developing in the jaw, and would have appeared after the usual time. The incisors showed considerable use. The height and thickness of the jaw and the size of the teeth reached the dimensions of those of a full-grown man of our time, and even surpassed them in some respects. The forward part of the jaw retreated so much as to obliterate the chin. These marks, similar to those that are observed in a still higher degree in other diluvial jaws, show that we have to deal with a man of very low organization. Professor Schaffhausen rejected the idea that the development of the teeth had been prevented by a pathological cause. Virchow opposed both the view that the jaw was like that of an ape and the one that it was a child's. The case was a rare instance of heterotopy in a man of gigantic size. The jaw was submitted to a committee, who subjected it to a careful examination and comparison. No one's views were changed, but the committee reported that the proportions of the teeth considerably exceeded those of a child's teeth, and reached those that are attained only in a full-grown man; it discovered nothing ape-like in the chin, but found, on measuring it, that, instead of retreating as it appeared to do, its line was perpendicular to the upper surface of the incisors, taken as a horizon. By carefully cutting away the plaster that held the left larger incisor in the preparation, an extraordinarily thick and plump root, rounded below, and quite different in its proportions from the normal, was brought to view; and the committee advised that the preparation of the specimen made by Professor Virchow be revised, so that the jaw could be subjected to a more thorough examination.

A Lignified Snake.—Naturalists are indebted to Senhor Lopez Netto, Brazilian Minister to the United States, for introducing to their attention a specimen of a phenomenon which, although it had been regarded as possible, had never before been observed that of an animal turned into wood. The specimen is that of a snake called the jararaca, one of the most venomous reptiles of the province of Matto Grosso, in Brazil, which, having crept into a crack in the bark of a tree, has died there, and afterward become lignified. As the cut shows, but less plainly than the specimen itself, the head, neck, and other parts of the animal are clearly delineated, and the most delicate details of the organization are plainly visible in many regions—as in the nostrils and the eye-cavities, and in the disposition of the scales and the cephalic plate on a whole half of the surface of the head. And the identity of the figure with the little jararaca of Brazil has been acknowledged to be evident by persons who are acquainted with that reptile. M. Louis Olivier, of the Botanical Society of France, who has made an anatomical examination of the figure, reports that he has found it to be composed of cells and fibers like those of the secondary wood which surrounds it. "The formation," he says, "can not be explained by saying that it has resulted from the deposition of the elements in a hollow, which, having been traversed by the animal, has preserved its form; for not only the contour of the serpent, but the whole relief of his form, is recognizable in the wood.

The Lignified Snake of Matto grosso (one half size of nature).

The entire body of the animal has been thus lignified, except the center, where the constituent elements of the animal still exist. Following the line of the projection of the head may be seen a cylindrical figure, also in relief, which seems to represent the larva of an insect. The deduction is therefore drawn that the reptile, pursuing the insect into a crack in the tree, had insinuated itself between the wood and the bark, or into the zone of the cambium, out of which the wood and inner bark are formed. Having died there, it went through the process of decay, in the course of which each animal particle as it was dissolved was replaced by a particle of woody tissue deposited by the cambium. The specimen was exhibited to the Botanical Society of France on the 9th of April last, when, as we learn from a note from M. Olivier to Senhor Netto, there were present M. Bonnet, President; M. Chatin, General Secretary, etc.; M. Duchartre, Professor in the Faculty of Sciences, etc.; M. Prillier, Professor at the Central School of Arts and Manufactures and at the Agronomic Institute; M. Malinvaud, Secretary and Librarian of the Society; Dr. Edmond Bonnet, of the Museum of Natural History; and M. Paul Petit. "These gentlemen, after having examined the specimen submitted to them, with the most lively interest, agreed, in explanation of the remarkable phenomenon which it presents, that there has been a gradual substitution of ligneous fibers and cells for the constituent elements of the snake. The reptile had introduced itself into a fissure of the tree between the wood and the bark, and had died there; and as rapidly as its flesh decayed the place which it had filled was occupied by the cells produced by the generative zone of the secondary wood, that zone becoming hypertrophied on contact with the animal, as is attested by the well-defined relief which it still presents. No objection was opposed to this interpretation of the facts; but in admitting the same explanation which I had endeavored to give you before the meeting, neither my colleagues nor myself intended to depreciate the importance of the phenomenon which is the object of it; the wood of the formation of the vegetable tissues appears sufficient to give an account of it. It is no less true that, in the opinion of the most competent persons, the specimen which you have made known to the scientific world is the finest example that has so far been brought forward in illustration of the theory of the normal play and accidental hypertrophy of the generative tissues of plants." The specimen was also shown to M. Van Tieghen. He was very busy, and able to give it only a cursory examination; but the opinion he expressed concerning its nature was fully in accord with that of his fellow-botanists. Dr. Edmond Bonnet and D. Adanson had recollections of specimens presenting similar characteristics to a certain extent, but declared that no known specimen offered nearly so complete an exemplification of the wonderful phenomenon of transformation as this one. The editors of this journal have been permitted, by the courtesy of Senhor Netto, to inspect the specimen, and are glad to add to that of the French botanists their testimony to its remarkable character.

Progress of Scientific Forestry.—Sylviculture, or the culture of forests, as it is understood and applied in the countries of Europe, where it has been studied as a science, is the application to woodland property of certain economical principles which, in their spirit, contain nothing more than what is held to be necessary for the well ordered management of landed property in general; and which may be summed up as follows: 1. The obtaining, within approximate limits, of a regularly sustained revenue from the land which the forest covers. 2. The utilization, to the fullest extent possible, of the natural productive powers of the soil. 3. Progressive improvement in the value of the property. 4. Final realization of the crop to the greatest advantage. "It is in the development of these principles," says Colonel G. F. Pearson, in a lecture before the British Society of Arts, "and in their application to forests of different sorts, that the true science of forestry consists." The rapid disappearance of the forests first attracted attention, in Europe, at about the beginning of the seventeenth century. The first measures to regulate the evil were not very efficient, but the subject came under the attention of the distinguished naturalists of the succeeding generations, and a system—that of tire el aire—was adopted. Under this system a period called a revolution was fixed, in which the forest was destined to be cleared off entirely, and reproduced by natural seeding. To this end the wood was divided into a number of compartments equal to the number of years in the revolution, one of which was felled every year, or at such regular intervals of time as were determined in the working plan, a few standard trees only being left as seed-bearers. This system was continued till within the last half-century, but did not prove efficient; and any approach to sound forestry was unknown in France till the forest-school was established at Nancy, in 1824. Considerable progress had been made before this time, even before the close of the last century, by the German foresters, who were the first to base the principles of the art on observation, and treat it in a scientific manner. Schools of sylviculture now exist in all the principal countries of Europe, except Great Britain; and Dr. Hough, of the United States, last year visited all the forest-schools of Europe, with a view of founding an American school. Considerable progress has been made in forestry in India, where steps for forming a regular forest administration were taken immediately after the mutiny. A policy of sending candidates to foreign schools to be trained has given the state a body of able men, thoroughly grounded in the management of natural forests covering extensive tracts of country. Within the last two years the Cape of Good Hope and Cyprus have been furnished with forest officers from France. The Mauritius, Ceylon, the Straits Settlements, Hong-Kong, Feejee, and other British colonies, are all following suit, and have recourse to Kew and other similar institutions for foresters. Of all the British colonies, South Australia is the one that is giving most attention to the subject. More would, undoubtedly, be accomplished in all the colonies had Great Britain a central institution for training a sufficient number of foresters to supply their needs.

Egypt as a Health Resort.—In estimating the merits of Egypt as a winter residence for invalids, Dr. Edith Pechey specifies dryness and equableness of temperature as the characteristics of climate chiefly demanded for such a purpose. Of the former quality one soon has practical proof in a Nile voyage. The hair gets very dry, the nails grow slowly and are very brittle, and all articles of use in some way give testimony of it. The air becomes drier with the ascent of the river, "and the dry heat is more easily borne than moist heat. One experiences no discomfort from the increase of temperature as one approaches the tropics; in fact, one thoroughly enjoys there what in Lower Egypt would be found quite oppressive." Egypt is not exempt from occasional sudden and great changes of temperature, but they are rare. Of much greater importance are the variations. The temperature falls suddenly at sunset for about half an hour, and another depression takes place in the early morning. The changes are very evident in a wooden boat, and from this fact constitute a great drawback in the dahabeeah voyage for invalids. In Nubia, the diurnal variation is much less marked, and the nights are only pleasantly cool. The life on the dahabeeah is a very enjoyable one, and "for cases of overwork nothing could be devised more calculated to restore and strengthen the intellectual powers than the Nile trip, and here no physician need hesitate for a moment. There are perfect rest, no railway bustle or jar, the variety of traveling in fact without the fatigue, with the constant enjoyment of sunshine and fresh air." Phthisical and rheumatic patients will also be greatly benefited, if they are careful in guarding themselves against the night and morning chills.

Cowries and African Currency.—Herr John C. Hertz has published a memoir, in the "Transactions of the Geographical Society of Hamburg," on the use and diffusion of the cowrie-shell (Cyprœa moneta) as a medium of exchange. The author's father dispatched a vessel to the Maldive Islands in 1844 for a cargo of cowries, to be sold to merchants for use in West African trade. Not finding as many shells there as they had anticipated, they completed their cargo with the larger and less valuable species of Zanzibar, where the cowries are burned into lime. Several cargoes of cowries were sent annually to Whydah and Lagos, where they were exchanged with the slave-traders for the Spanish doubloons they received from the sale of slaves. The Hamburg ship-captains dispatched this money home from Cape Town. The cowrie-trade continued to extend as the slave-trade flourished, till Brazil took measures to prevent the introduction of African slaves. Simultaneously with the extinction of the slave-trade began the introduction of palm-oil, and a new trade, in which that product took the place of the Spanish doubloons, that grew as the use of palm-oil was extended. It flourished greatly during the Crimean War, when the Black Sea tallow was excluded from the markets. With it also flourished the trade in cowries, which thus appears to be connected with so many historical events that, considered from that point of view, it may be regarded as in some sort a measure of historical development—a view which received another exemplification in 1852, when England blockaded the coast of Dahomey, and the trade in cowries was stopped. In 1845 the Sultan of Bornoo reformed his currency, and introduced Spanish doubloons in place of the cotton-cloth that had hitherto served as money, with cowries, at the rate of four thousand to the dollar, for small change. A large demand for cowries sprang up, and the trade in them was stimulated to such an excess that the market was glutted, and it afterward languished for several years. The present demand is quite lively. The cowrie-shell is used as currency principally in the countries near the Niger, except in Ashantce, where gold-dust is the medium of exchange. North of Ashantee, gold-dust and the gera or cola-nut (Sterculia acuminata) are used with cowries, a load of sixty pounds of the nuts being considered equivalent in value to about fifteen thousand cowries. The shells have been used as a medium of exchange from a high antiquity. Marco Polo found them circulating in Yunnan in the thirteenth century; and they have been discovered in prehistoric graves in the Baltic countries. Herr A. Wörmann says, in a paper of the Hamburg society, on trade by barter in Africa, that a variety of objects besides cowries serve as measures of value in the different countries of that continent. Among them are pearls, little Nuremberg looking-glasses, iron, copper, brass, cloth, salt, tobacco-leaves, writing-paper, the colanut, goats, horses, cattle, and slaves; and the regions in which each of these articles circulates are defined by fixed limits. Iron and copper from Egypt circulate in the upper Nile region; Maria-Theresa thalers and cowries in Soodan; cowries, pearls, and "Mericani" (unbleached goods) on the East coast and in the region of the Arab trade. South and west of these countries are distinct trade-regions that have no direct connection with them, in each of which a different currency is needed, although ivory and slaves are the only products.

Shooting-Stars, their Traditions and their Origin.—The appearance of comets and shooting-stars announced to the ancients and to our ancestors the death of some grand personage or some woe, and the chronicles are full of notices of such phenomena. The notices are, in fact, occasionally so numerous as to be suspicious, for, as Lubienietz remarks in his "Cometography," when an event of such a kind happened, it was thought there must have been a comet about the time, and so it was put down; and an amusing picture has been made of the perplexity of a cometographer who could not find any comet for seventeen years, portentous of the events that were to happen during that period. The Chinese records are more trustworthy, for their observers were constantly at their posts, and formed a regularly and scientifically organized body. The documents recording the observations were specially preserved; for the Chinese, from a time many centuries before the Christian era, attributed to the different stellar groups a direct influence on the different provinces of their country. As shooting-stars may be seen at almost any time, it was to be expected that a great number of notices of the phenomena must have been recorded during the forty centuries of which we have a literature of some kind. Plutarch, in his biography of Lysander, makes a near approach to the modern explanation of the origin of these bodies, saying, "Some philosophers believe that the shooting-stars are not detached parts of the ether which go out in the air soon after they have been inflamed, that they no more originate in the combustion of the air which is dissolved in great quantity in the upper regions, but that they are rather falling celestial bodies." The general opinion is, that shooting-stars are bodies of small dimensions that circulate, under the influence of attraction, among the planets in the same way as the planets themselves. When they cross our atmosphere, the friction develops heat enough to consume them, most frequently before they reach our soil. The mean height at which the meteors become luminous exceeds, however, the estimated height of our atmosphere. Poisson has, therefore, suggested that, as they could hardly have become inflamed from friction at such a height, an atmosphere of neutral electricity may exist considerably beyond the mass of the air which is subject to the earth's attraction, and is disturbed by the entrance of the meteors, so that they become electrified and incandescent. Any theory to account fully for the origin of shooting-stars must explain the periodic swarms. For this reason, the theory of ejectment from lunar volcanoes must fail, even were it not otherwise shown to be baseless. M. Faye accounts for the August meteors by supposing a meteoric belt circulating around the sun which crosses the ecliptic at a point where the earth must meet it at the time of the annual shower, but this leaves the November meteors still unexplained. Schiaparelli and Le Verrier have suggested that the November meteors originate in a swarm of corpuscles which move in orbits very close to each other, having a period of about thirty-three years, and elements very similar to those of Temple's comet. Schiaparelli also connects the August meteors with the comet of 1861, and other swarms have been similarly connected with different comets. The Chinese annals furnish data which indicate that the greater number of shooting-stars are seen when the earth is passing from the summer solstice to the winter solstice, and this appears to be confirmed by the phenomena of the August and November meteors. The ancients and the authors of the middle ages abound in notices of portents, falling stars, fiery spears, fiery swords, burning skies, showers of blood, etc., a large proportion of which may be referred to shooting-stars. The earliest record so far found is the statement that Zoroaster was destroyed by fire, assigned to 2057 b. c. and the next the destruction of Sodom and Gomorrah, 1915. Many of the middle-age accounts give the phenomena the appearance of armies and battles in the sky.