Popular Science Monthly/Volume 14/November 1878/Popular Miscellany

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Popular Science Monthly Volume 14 November 1878  (1878) 
Popular Miscellany
 

POPULAR MISCELLANY.

Effects of Oxygen inhaled at Different Temperatures.—Dr. B. W. Richardson finds great diversity in the action of oxygen on the animal economy according to the temperature of the gas when inhaled. Carefully-purified oxygen may be inhaled at 55° Fahr. without a consciousness of the difference between it and common air. But before long, even though the products of the combustion of the animal be all removed, there is a gradual decline of the animal's temperature, followed by a tendency to sleep. At last death occurs in deep sleep. At a temperature lower than 55°, the narcotism produced by the oxygen is very much quickened. At 32°, in a chamber of oxygen, Dr. Richardson has seen deep coma induced in mice, pigeons, and Guinea-pigs, within thirty-five minutes of the commencement of the inhalation, death from coma supervening within an hour. In a raised temperature (75°), the inhalation of oxygen may be sustained without coma, indeed without injury, for a considerable time. To determine this point, Dr. Richardson constructed a small room that could be steadily ventilated with pure oxygen gas. In this room he kept adult warm-blooded animals on one occasion for three weeks without being able to observe any variation from the natural life that could be considered detrimental. In this instance the blood was always of the same color in the veins as in the arteries, viz., of a rich bright arterial crimson. Another experiment showed that, like heat, electricity modifies oxygen as a supporter of animal life. Dr. Richardson placed three full-grown mice in jars, each containing a hundred cubic inches of pure oxygen gas. One of these animals was placed now in a temperature of 45° Fah.; another in a temperature of 75°; the third was placed in the same temperature as the first, but with this difference, that into the jar containing the animal there was introduced a pointed copper wire connected with the positive conductor of a frictional electric machine. When the machine was set in motion, a brush was produced at the point of the copper wire. Every five minutes this electric brush was excited within the jar. The animal in the first jar would sleep to death in two or three hours; those in the second lived for many hours; in the third the animal fell into a narcotized condition, but nevertheless continued to live in sleep so long as the electrical excitation continued. Under these conditions it lived for seventeen hours in gentle sleep, and on being then set free showed no sign of injury, and lived on as before the experiment.

 

A Torpedo Transport.—A war-vessel of an entirely novel character, the Hecla, lately arrived at Portsmouth, England, from Belfast, where she was constructed for the British naval authorities. The Hecla is designed to carry fast torpedo launches and to follow in the wake of a fleet as a depot, ready to dispatch her flotilla of small craft for its protection when needed. She is an iron vessel, 390 feet in length, and is fitted to carry six sixty-four-pounder rifled guns. On each side is a broadside port through which Whitehead torpedoes may be launched. The after-part below is fitted up as a torpedo workshop. The hull is divided into a number of water-tight compartments, not connected, as is the usual mode, with watertight doors, entrance being gained from the upper and main decks. The element of danger resulting from leaving the connections open in certain eventualities is thus obviated, though it is calculated that the filling of one or two of the compartments with water would not materially affect the behavior of the ship. She is to carry six second-class torpedo-boats. Four of these boats will be amidships, the chocks on which they rest running on a tramway. She will also carry a 42-feet steam launch and a 37 feet steam pinnace. The Hecla will be provided with booms and nets to protect her from an enemy's torpedoes—the booms, when not in use, lying fore and aft against the side of the ship.

 

Women and the Study of Science.—The medical profession in England appears to be seriously alarmed at the prospect of an invasion of its ranks by womankind. Scientific workers need have no such fears of their peculiar field being occupied by the gentler sex, if the "Cambridge Higher Local Examinations," lately held, are any index of the disposition of women-students in England toward scientific studies: only about thirty out of five hundred female students, we are informed by Nature, took the science subjects; twenty-one took botany, one failed, and three obtained distinction; twenty-six geology and physical geography, of whom two failed, and seven were distinguished; seven geology, one failed, three distinguished; nine chemistry, three failed, none distinguished. Ten of the science candidates sat at Cambridge, and among them they gained ten out of fourteen of the distinctions given. Miss E. M. Clarke, of Cambridge, was distinguished in geology, zoölogy, and botany, and passed in chemistry. Mathematics got only twenty-three candidates, of whom four failed; only two, however, were placed in the first class (being Cambridge students), and two in the second. We are glad to learn that two new subjects are to be set in the science group next year, namely, physics and physiology, the latter so much needed in all girls' schools. Also, students will be allowed to take this group without having to pass Group A (literature and history) first, although it will be required for a full certificate.

 

Sir Wyville Thomson on Deep-Sea Soundings.—Sir Wyville Thomson, as President of the Geographical Section of the British Association, delivered an address, at the Dublin meeting of that body, on the results of recent deep-sea sounding. He dwelt particularly on the facts of ocean circulation as developed by the Challenger Expedition. All recent observations, he said, have shown that the vast expanse of water which has its centre in the southern hemisphere is the one great ocean of the world, and the Atlantic with the Arctic Sea, and the North Pacific, are merely its northward-extending gulfs: any physical phenomena affecting obviously one portion of its area must be regarded as one-of an interdependent system of phenomena affecting the ocean as a whole. Shallow as the stratum of water forming the ocean is—a mere film in proportion to the radius of the earth—it is very definitely split up into two layers, which, so far as all questions regarding ocean-movements are concerned, are under very different conditions. At a depth varying in different parts of the world, but averaging perhaps five hundred fathoms, there exists a layer of water at a temperature of 40° Fahr., which may be regarded as a sort of neutral band separating the two layers. Above this band the temperature varies greatly over different areas, the isothermobathic lines being sometimes tolerably equally distributed, and at other times crowding together toward the surface, while beneath it the temperature almost universally sinks very slowly and with increasing slowness to a minimum at the bottom. With some reservation it may be affirmed that the trade-winds and their modifications and counter-currents are the cause of all movements in the stratum of the ocean above the neutral layer. All the vast mass of water, often upward of two thousand fathoms in thickness below the neutral band, is moving slowly to the northward; in fact, the depths of the Atlantic, the Pacific, and the Indian Ocean, are occupied by tongues of the Antarctic Sea, preserving in the main its characteristic temperature. The explanation of this seems simple. For some cause or other as yet not fully understood, evaporation is greatly in excess of precipitation in the northern portion of the land-hemisphere, while in the water-hemisphere, and particularly in its southern portion, the reverse is the case: thus one part of the general circulation of the ocean is carried on through the atmosphere, the water being raised in vapor in the northern hemisphere, hurried by upper-wind currents to the zone of low barometric pressure in the south, where it is precipitated in the form of snow or rain, and welling thence northward in the deepest channels, on account of the high specific gravity dependent on its low temperature, it supplies the place of the water which has been removed.

 

A New Form of Stereoscope.—It is known to many people that, by placing the axes of the eyes parallel, it is possible so to see stereoscopic pictures without any instrument as if we were looking at them through stereoscopic lenses. To do this, we may make a small hole in the centre of each picture, and hold the paper in such a position that each eye looks through the hole at a distant object. But with ordinary stereoscopic pictures this object needs to be very far off, so that this contrivance is

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not a very convenient one; nor is it desirable to make a hole in the centre of every picture we wish to see stereoscopically with our naked eyes. Another method is to make one familiar with the muscular sensibilities of the eyes according as their axes converge or diverge, and to make him acquire such control of his eyes that, without looking at any distant object, he will be able to place the axes of the eyes parallel. Though either of the above methods would answer for experimental purposes, neither would serve as a substitute for the ordinary stereoscope; for if one requires such an inconvenient arrangement, the other requires too much trouble in explaining. But I thought that, perhaps by some happy, simple contrivance, we could see stereoscopic pictures unaided by any lenses, yet without any conscious straining of our eyes; and after repeated experiments I found out that, if corresponding parts of two pictures were apart from one another only one inch and a half or so, and if by means of a partition the two pictures were so separated from one another that the right eye will see only the right picture and the left eye the left picture, the two pictures will combine just as easily as with an ordinary stereoscope.

The following is my explanation why two pictures combine so easily when corresponding parts of the two are apart only one inch and a half or so, while to make ordinary stereoscopic pictures combine requires so great effort:

To combine ordinary stereoscopic pictures unaided by any lenses, the axes of the eyes must be placed parallel; but, since it is not an habitual position of our eyes to have their axes parallel, this can only be accomplished by a great effort. But, if to place the axes parallel requires such an effort, to make them too convergent requires equally great effort. Thus to see a single image of a finger put on the tip of our nose is very difficult, and to see a single image of the tip of the nose itself is almost an possibility. With the habitual positions of our eyes, the axes are neither parallel nor too convergent, and we see dimly two images of our nose and objects too near our eyes. Now, when corresponding parts of two stereoscopic pictures are apart from one another only one inch and a half or so, and are distant from our eyes one foot or so, to combine the two pictures our eyes are only required to take one of their habitual positions; that is, the axes of the eyes need only to be so placed as if we were looking at an object distant from our eyes two feet or so: hence the effort required is very trifling, even when unaided by any instrument. But when the two pictures are so separated by a partition that the right eye can see only the right picture and the left eye the left picture, the combination of the two will take place as easily as with an ordinary stereoscope. This is, I think, chiefly owing to the fact that as long as the two pictures are seen separate, the picture seen by each eye is covered by a dim image of the partition seen by the other eye, and it is only when they combine that we have a clear and distinct view of the pictures.M. Toyama.

 

Natural Selection.—An interesting case of the operation of the law of natural selection and the survival of the fittest is recounted in the American Naturalist, by S. F. Clarke. Having obtained a number of the gelatinous egg-masses of one of our native salamanders, he placed them in large glass jars, where they developed rapidly. After their gills and balancers had developed, they emerged from the eggs and began their active life in the water. A difficulty now appeared—the author could not discover the proper kind of food. Upon watching the animals closely, however, he soon found that they were eating off one another's gills. Closer examination showed that among the many were a few individuals which, although they came from the same parents and were subjected to the same conditions while in the egg, were yet gifted with greater vigor than most of their fellows. These few stronger ones ate off the gills of many of the weaker, and at the same time were enabled to protect their own gills from mutilation. These favorable conditions, the large supply of food, and the better aeration of the blood, soon began to show their influence upon the growth of the favored individuals. Within a week or ten days from the time of emergence from the egg, these favored few were fifty per cent, larger than their weaker comrades who were born upon the same day. Their mouths had by this time so increased in size that, no longer satisfied with nibbling off the gills of their brethren, they now began to swallow them bodily. Soon they were ten or twelve times as great in length and bulk as their victims.

 

Carnivorous Caterpillars.—A striking peculiarity of the caterpillars of Patagonian Lepidoptera, namely, their cannibalism, is noticed by Prof. Carl Berg. All caterpillars in Patagonia, of whatever family or group, prey upon their own kind. He kept them in captivity, and found that, even with an abundance of food-plants at hand, they preferred to devour one another, "hair and hide;" they even tear open the cocoons and prey on the chrysalids. One was observed to devour in twenty-four hours six or seven individuals of its own species. This peculiarity of Patagonian caterpillars is thus explained by the author: During the summer there are extreme heat and drought in Patagonia, and these causes, together with the prevailing dry winds, parch the vegetation, scanty at best. The caterpillars are in consequence greatly straitened for food, and the struggle for life has led them to seek some other means of subsistence. Hence their cannibalism, which, being transmitted by heredity from generation to generation, becomes a second nature, and the practices to which they were at first driven by want they now perpetuate through habit.

 

A Battle-Royal among Ants.—F. E. Colenso, of Maritzburg, Natal, in a letter to Nature, gives an animated description of a fierce battle between ants, which he found engaged in mortal combat on his garden wall. Among the ants was a considerable number of larger individuals, "the soldier-ants" of the same species, and the whole ant community seemed to be bent on destroying them. A group of little ones would fasten on to a big one, the latter in the mean time making desperate efforts to free itself. Or a big one would bite several little ones in two, but after a while the little ones would have severed all the legs of the big one, and finally would get on his back and cut him in two. One combat was especially noticeable, and is described as follows by the author: "A big ant walked along till it met another big one, and the two shook antennæ. Just then a little one seized hold of a hind-leg of one of these big ones. Neither took any notice, but continued a rapid conversation. Suddenly other small ones came up, when the big one whose leg was grabbed turned furiously on the little one and seized him by the middle. This could not be done until the big one had doubled himself up; as soon as he had hold of his small antagonist, he lifted him in the air and snipped him in two. Meanwhile all the big one's legs had been seized by little ones, and the party seemed to turn over and over, little bits tumbling down off the wall, now a leg, now half an ant, till the big one was vanquished. The way in which the big ant turned on the little one was singularly indicative of rage. The determined manner in which he laid hold of the little one was quite human."

 

How the Silk-worm Moth escapes from its Cocoon.—Having heard a rustling, cutting, and tearing noise issuing from a cocoon of Actias luna, the large green swallow-tailed silk-worm moth. Prof. A. S. Packard supposed that the moth must be engaged in cutting its way out of the cocoon. And as the mode of escape is a subject of dispute among entomologists. Prof. Packard determined to observe the moth at its work. A sharp black point was seen moving to and fro, and then another, until both points had cut a rough, irregular slit, through which the shoulders of the moth could be seen vigorously moving from side to side. The slit was made in one or two minutes, and the moth worked its way at once out of the opening. Afterward, in examining two dry specimens of the same moth, this black point or spine was seen at the base of each fore-wing; Mr. Packard calls it sector coconis—the cocoon-cutter. A number of other members of the sub-family Attaci having been examined, the sector was found in them all. In the common silk-worm (Bombyx mori), the spines are not well marked, and they are quite different from those in the Attaci, and consist of three sharp points, being acute angles of the pieces at the base of the wing.

 

The Musk-Bison.Ovibos moschatus (musk sheep-ox, i. e., the musk-ox), as its systematic name indicates, possesses external characters common to the sheep and the ox, and hence it has been regarded as forming the connecting link between these two species. But, as a writer in Land and Water points out, the name given to the animal by Pennant, namely, musk-bison, more correctly defines its zoölogical position. Of this interesting animal, the writer just mentioned says that it measures only about five and a half feet from the tip of the nose to the root of the tail. Its average weight is usually estimated by travelers at 700 pounds, but the author thinks that 800 pounds would probably be nearer the weight of the largest individuals. The outer hair, or fleece, is long and thick, brown or black in color, frequently decidedly grizzled, hanging far below the middle of the leg. Underneath this shaggy coat, and covering all parts of the animal, though much the heaviest upon the neck and shoulders, is found a fine soft wool of exquisite texture, of a bluish-drab or cinereous hue, capable of being used in the arts and of forming the most beautiful fabrics. It is this close under-fur which enables its wearer to withstand the bitter storms and piercing cold of arctic winters, even beyond the seventieth parallel of latitude. The head is large, ending in a rather short muzzle, though remarkably broad nose, the nostrils being bordered and separated by a naked narrow space. The forehead is convex, and both sexes are provided with horns, which are of extreme size, and not unlike those of the male of the Rocky Mountain sheep in curve and general appearance, but lacking the transverse corrugations that characterize the latter. In the male, these appendages approach so closely together in the centre of the forehead as to appear to be joined at their bases, as they undoubtedly are in old age. Leaving the point of insertion, the horns are directed outward and laterally, falling down abruptly on either side of the face, curving slightly forward through their middle third, and, opposite the angle of the mouth, turning sharply upward at the tip. In the female they are placed farther apart in the skull, measure much less in circumference at the point of insertion, and, though they likewise fall down and present the same curve as those of the bull, the points are not in the least inclined upward, but rather down, or in the same plane with the lips. They are powerful weapons, however, serving both sexes equally well either for offense or defense. They are very broad next to the skull, but taper swiftly toward the points, which are very sharp, and present a dull whitish-yellow color, rough at the basal extremity, but smooth and shining beyond, and black at the tips. The average proportions of a pair of horns are two and a half feet across from tip to tip, and each two feet in length, measured from the median line of the forehead, to which they are attached by a characteristic boss or protuberance. A pair frequently weighs upward of sixty pounds. The tail is very small, and completely hidden by the long hair of the voluminous fleece. The legs, too, are short and greatly concealed by the long hair of the shoulders and flank. The feet are four-toed, and armed with hoofs like all ruminants, the two anterior and largest being broad and inflexed, with sharp cutting edges, and the posterior or lateral ones, which are but slightly developed in most quadrupeds, are considerably prolonged, almost reaching to the ground; this, with the upward curve and great expansion, of which the front hoofs are capable, presents a structure which, by giving the animal a broader base to stand upon, prevents its sinking too deep into the snow, or when traversing boggy ground. Without this, the musk-ox would have been as ill-fitted to tramp over the yielding snow-fields of the north as the camel to perform long marches through the burning sands of tropical deserts without his broad, elastic sole-pad.

 

Sagacity of the Beaver.—A Mississippi correspondent of Chambers's Journal recounts several interesting instances of the sagacity of the beaver, and of the readiness with which that animal grows accustomed to the presence of man. At a place near this correspondent's residence a railroad crosses some wet, springy ground, where there used to be several beaver-dams. The line of embankment supplied the place of these dams, and the beavers, taking the good the gods provided, worked no more on their own dams, but enjoyed the pond of four or five acres which the embankment had made for them. A year or two since, the railway-workmen undertook to put a culvert through the embankment and drain the pond, which, after running freely for a few days, and nearly emptying the pond, suddenly stopped one night: the flow had been arrested by the beavers. The men opened it again, but once more it was stopped up. This went on for some time. As the men passed that way they would open the entrance to the culvert, and at night the beavers would shut it up. At length, finding that closing at the entrance, where their work could so easily be broken down, did no good, the beavers moved their dam to the middle of the culvert, which was some forty feet long, out of the reach of the poles used to poke it down. Here was a community of beavers working with express-trains thundering over their heads!

 

A Useful Snake.—In "Notes on the Natural History of Fort Macon, North Carolina," contributed to the "Proceedings" of the Academy of Natural Sciences of Philadelphia, Drs. Coues and Yarrow describe the king-snake (Ophibolus getulus), which is said by the residents frequently to destroy both rattlesnakes and moccasins, eating its victims after the conflict is over. For this reason the king-snake is in great esteem, and is carefully protected. The fight which takes place between the ophibolus and the rattlesnake has often been witnessed, and is described as follows: So soon as the rattlesnake sees his enemy, he endeavors to escape if possible, and, failing in this, he instantly throws his body into coils. The King-snake approaches swiftly, and moves around the rattlesnake in a circle, gradually drawing nearer and nearer, the rattlesnake following his motions with his head. The circular movement of his antagonist appears finally to disconcert him, for after a time it is noticed that his movements are less energetic, and at length, in an unguarded moment, ophibolus throws himself suddenly upon him and chokes him to death, pulls his body apart, and devours him. In captivity the king-snake is very gentle, and it requires very severe provocation to induce it to bite. Several specimens which were kept in a large box could not be induced to eat either mice, frogs, or toads; but as several fine specimens of Ophiosaurus ventralis, kept in the same box, quickly disappeared, it was easy to account for the apparent want of appetite.

 

The "Uses" of Pain.—The question is often asked, "What is the use of pain? It is scarcely conceivable that the infliction has no object." There are obviously two aspects of this question: in one Science has an immediate interest; with the other it has a secondary but not unimportant concern. The first is essentially physical. What useful purpose does pain subserve in the animal economy? The answer is thrust upon us by daily observation and experience. There are two sentinels posted, so to say, about the organism to protect it alike from the assaults of enemies without and exacting friends within. The first of these guardians is the sense of fatigue. When this speaks, there is need of rest for repair. If the monitor be unheeded, exhaustion may supervene; or, before that point of injury is reached, the second guardian will perhaps interpose for the vital protection—namely, pain. The sense of pain, however, is more directly significant of injury to structure, active or threatened, than an excessive strain on function, although in the case of the vital organs pain occurs whenever the pressure is great. Speaking generally, it may be set down as an axiom that, whatever collateral uses pain may subserve, its chief and most obvious service to humanity is as a deterrent and warning sensation to ward off danger. It is worthy of note, though sufficiently familiar to medical observers, that the absence of this subjective symptom in cases of severe injury is too often indicative of an injury beyond repair. The extinction of pain is not the highest, although it may be a generous, impulse. If there were no guardian sensibility of this nature, it would be impossible to live long in the world without self-inflicting the most formidable injuries. That pain, in the second place, has an educational value, as regards the mind and temper, no one can doubt. Some forms of pain would seem to be chiefly intended for this purpose; but even in this view pain has a practical interest, because the higher development of the mind which controls the body, and of which the brain is the formative organ, is a process of physico-mental interest governed by natural laws of which Science is perfectly competent to take cognizance. The subject as a whole is one with which the physician and physiologist have much concern.—Lancet.

 

Discovery of a New Salt-Deposit in Central New York.—Mr. James McFarlan announces the discovery of a bed of rock salt in the Onondaga salt-group at a locality thirty-seven miles south of Rochester. The boring which resulted in this discovery passed first through 660 feet of shales, then 110 feet of hard rock—sandstone or limestone—then 80 feet of hard limestone, when salt-water was found. Below this was 380 feet of limestone and shale belonging in part to the limestones and shales of the upper part of the Onondaga salt-group; next, 1,240 feet down, soft shales, 20 or 30 feet thick, were passed through; and, finally, the bed of rock-salt was struck at the depth of 1,279 feet. It had a thickness of 70 feet, of which 40 or 50 was pure salt. The boring was continued to the depth of 1,530 feet, down to the Niagara limestone, which was met at 1,562 feet. Borings are to be made on the south side of the Syracuse Valley, in the expectation of striking the same bed, which there would be found, if at all, at the depth of only a few hundred feet.

 

Distribution of Spiders.—In classifying the collection of spiders in the museum of the Academy of Natural Sciences of Philadelphia, the Rev. H. C. McCook discovered specimens of Sarotes venatorius, a large spider coming from various localities—from Santa Cruz (Virgin Islands) to Cuba, to Florida; across Central America, Yucatan, and Mexico; across the Pacific Ocean by way of the Sandwich Islands, Japan, and the Loo-Choo Islands, and thence across the continents of Asia and Africa to Liberia. He noticed that this line of distribution lies within the belt of the north trade-winds, and conjectured the existence of some connection between the two facts. Probability was given to the conjecture by the migratory habits of this spider in the early stages of its growth. The young spider emits from the spinnerets fine threads in sufficient bulk to overcome the specific gravity of the body, and it is borne through the air like a balloon. We some time ago gave an account of Mr. McCook's observations on ballooning spiders. Having found this spider in localities lying in the track of the northern trades, Mr. McCook made an investigation to determine whether the species is distributed along the entire track, and also whether it is to be found in the track of the southern trades. The result is exhibited by the author in a map which shows the existence of Sarotes venatorius in both belts of the trades, from the east coast of America, across this continent, the Pacific, and the whole Eastern Continent, to the west coast of Africa, thus girdling the globe, with the exception of 54° of longitude corresponding to the width of the Atlantic Ocean. The inference is that the distribution of this spider has been accomplished by means of the trade-winds.

 

The Growth of Mushrooms.—It is generally supposed that mushrooms grow only in the night, but those who have watched them have observed that their growth is nearly equal day and night. A correspondent writes that not long since a flower-pot was filled with dirt from the street, a plant was placed therein and it grew rapidly. In ten days a small mushroom made its appearance, but in a few hours it toppled over and perished. On the following day a larger one of different species was discovered peeping through the soil, and in the morning it was just above the surface. Before nine o'clock at night it attained its full height, nearly four inches, although it was in the sun several hours, and gradually expanded its acorn-head into a hollow cone which united with the hollow stem at the interior of the apex. Its inner surface was lined and evenly shirred with a black, velvety substance which made a fine contrast with the milk-white, cobweb-like substance of the outer surface. During the day and night the head was transformed into an umbrella-like cap, which collapsed and died on the fourth day. Others of different species, made their appearance at different times, showing that the streets of a city as well as the soil of the country are filled with spores of these seedless and flowerless plants ready to show themselves whenever the conditions of germination are favorable. They do not propagate by seeds—they have none—they propagate by spores, microscopically small, which are driven hither and thither by winds and lodged in various places, and when they receive the requisite amount of moisture and heat they germinate and grow to perfection, whether it be day or night.

 

Mercurial Deposit on Animal Teeth.— On the teeth of a sheep said to have been poisoned by the herbage growing in the neighborhood of a certain silver-mine in Mexico, Mr. E. Goldsmith, of the Academy of Natural Sciences of Philadelphia, noticed a peculiar deposit of tartar, which was supposed to consist of silver amalgam. Upon examination this tartar was found to constitute a thin scale covering the teeth to the depth of about 0.2 millimetre. Viewed under a lens of moderate power, the deposit seemed to have been built up gradually from within. Its lustre was truly metallic. Heated on platinum-foil it became black, showing the presence of organic matter. Heated in a tube closed on one end, at first a gray cloud arose, then water and an oily matter deposited themselves on the upper or cooler end of the tube; lower down near the now carbonized test a metallic layer was recognized with the aid of the lens. The powdered substance being mixed with carbonate of soda, and treated in the same way, the result did not differ. If melted on coal with the addition of carbonate of soda, there was obtained a white enamel, but no metal whatever. In nitric acid the tartar was soluble as long as the solution was concentrated; if diluted with water, a turbidity, caused by the separation of an organic matter, was formed. This organic matter was soluble in caustic ammonia, and from this ammoniacal solution it was again precipitable by nitric acid; the precipitate was flocculent, it carbonized when heated, and left no residue if the heating was prolonged for a sufficient time. The remaining solution from which this organic substance had been separated gave no reaction with hydrochloric acid, the absence of silver being thereby proved. A stream of sulphureted hydrogen gave a precipitation in which a very little quantity of sulphuret of mercury was discerned. Very strong reactions of phosphoric acid and lime were observed in the nitric-acid solution with the ordinary reagents. This singular tartar is consequently not silver amalgam, but the same material of which teeth are generally made, modified, however, by the influence of a small quantity of mercury. That metallic mercury is easily absorbed by the animal economy is well known; it seems, however, not to have been noticed on the outside of the teeth before.

 

The Grave-Digger Beetle.—In order to test the strength of the grave-digger beetle (Necrophorus Germanicus) Mr. Gleditch, an entomologist, half filled a glass vessel with earth, into which he put four of the beetles with a dead linnet. The grave-diggers immediately began to excavate beneath the dead body of the linnet, shoveling away the earth on each side. After laboring for nearly two hours, one of the beetles was driven away and not allowed to work again. The others continued their labor, until one by one they ceased, leaving only one beetle at work. Five hours, more hard work was given by the remaining beetle, who at last sank exhausted on the earth and rested from his task, and finally, suddenly rousing himself, stiffened his collar, and by an extraordinary effort of strength lifted up the bird and arranged it within the spacious grave. In three days the grave was finished, and the bird safely deposited within its narrow limits. During a space of fifty days, these busy workers interred the bodies of four frogs, three small birds, two grasshoppers, and one mole. This singular occupation, which continues from the middle of April until the end of October, proceeds from an instinctive desire for the preservation of their offspring. Eggs deposited by the' parent in the substances which they inter, when hatched, produce larvæ, which, feeding on the carrion which surrounds them, grow to an inch in length. These in their turn change into yellow chrysalids, and lastly into beetles; and the latter, when emerged from the earth, begin to dig graves and inter dead animals for the benefit of another generation.

 

A New Mineral White.—For many years chemists have been trying to find some mineral white which might be substituted for the costly and poisonous white-lead. One of the substitutes proposed was zinc-white—oxide of zinc—but the "body" of zinc-white will not bear comparison with that of white-lead. Oxide of antimony, and the silicates of zinc, magnesia, and lime, were successively tried, but none of these substances proved to be an adequate substitute. Mr. T. Griffiths, of Liverpool, has obtained a mineral white the basis of which is sulphide of zinc, and which Dr. Phipson pronounces to be "in every respect superior to carbonate of lead itself," i. e., white-lead. It is obtained by precipitating either chloride or sulphate of zinc by means of a soluble sulphide—sodium, barium, or calcium sulphide—and precautions are taken lest any iron that may be present in small quantity should be precipitated with the white sulphide of zinc. The precipitate, being collected and dried, is transferred to a furnace, there calcined for some time at a cherry-red heat, and carefully stirred so as to bring all parts of it successively in contact with the air. It is then raked out while quite hot, into vats of cold water, where it is levigated, and afterward collected and dried. The result is a very fine white pigment; its covering power when mixed with oil is about 25 per cent, higher than that of carbonate of lead. Phipson's analysis of the new product shows it to be an oxysulphate of zinc. This white is not darkened by sulphureted hydrogen, and its manufacture is perfectly innocuous.

 

A Substitute for Gutta-Percha.—We take from an English journal the following account of a substance called balata, the milky sap of the bully-tree, which grows in the region of the Amazon and the Orinoco: Balata, we are informed, possesses many of the characteristics of India-rubber and gutta-percha; indeed, it so closely resembles the latter substance in its general properties, that much of it is shipped yearly from Guiana and sold for that article, although in some respects it is greatly superior to gutta-percha. Like gutta-percha and India-rubber, this gum is obtained by making an incision in the bark of the tree, and allowing the sap to ooze out and either coagulate in a lump or flow slowly over a clay form so as to produce a "bottle" or any other pattern that may be desired. Balata is tasteless, gives out an agreeable odor on being warmed, is tough and leathery, is remarkably flexible, and far more elastic than gutta-percha. It can be softened and joined piece to piece indefinitely, at a temperature of about 120° Fahr., but requires a beat of 270° before it melts. It is completely soluble in benzol and bisulphide of carbon when cold. Turpentine dissolves it with the application of heat, while it is only partially soluble in anhydrous alcohol and ether. It becomes strongly electrified by friction, and is a better isolator of heat and electricity than gutta-percha. Caustic alkalies and concentrated hydrochloric acid do not attack it, but concentrated sulphuric and nitric acids do. A sort of artificial India-rubber, called "kerite," invented by A. G. Day, of this city, has recently been brought to. notice. It is prepared in the following way: About twenty-seven pounds of cotton-seed oil and thirty pounds of coal-tar are mixed together in a boiler, with sufficient heat and for a sufficient length of time to cause them to unite thoroughly. The temperature should be about 300° Fahr., and the time is from three to five hours. The mixture is then cooled to from 200° to 240° Fahr., and then linseed-oil (twenty-seven pounds) is added. When the latter has been thoroughly mixed with the other ingredients, twelve to sixteen pounds of sulphur is added gradually, the temperature meantime being steadily raised to about 275° or 300° Fahr. The heating is continued till the mass is vulcanized. When the vulcanization is complete, the compound is finished, and it may then be poured into moulds or pans and allowed to cool for use. The inventor has lately made some considerable improvements in his process of preparing ozokerite, but it would take too much space to detail them here.