Popular Science Monthly/Volume 2/February 1873/Miscellany

From Wikisource
Jump to navigation Jump to search


Volcanic Energy.—Mr. Mallet, in a paper read before the British Royal Society, claims that volcanic heat results simply from the secular cooling of a terraqueous globe subject to gravitation. He rejects the chemical theory, on the ground that facts show the chemical energies of the globe almost wholly exhausted prior to the consolidation of its surface. The mechanical theory he also rejects, it being, according to him, proved untenable by the known thickness of the earth's crust. He then points out various relations and points of connection between volcanic phenomena, seismic phenomena, and the lines of mountain elevation, attributing all three to one set of cosmical forces, which decay with time. As our globe contracted, there occurred deformations of the spheroid, forming the ocean-basins; next came the foldings-over and elevations of the thickened crust into mountains; and, lastly, we have volcanic action. The author accepts C. Prevost's theory of mountain elevation, viz., tangential pressures propagated through a solid crust, and produced by the relative rate of contraction of the nucleus and of the crust. As the nucleus shrinks, the crust is partially unsupported. During the very rapid cooling from a high temperature, with a thin crust, we should have mountain elevation as a result; but the same causes give rise, in the present state of things, to volcanic heat. As the solid crust sinks after the nucleus, its crushing together is transformed into heat sufficient to fuse the rock. The access of water then determines volcanic action. Mallet made two series of experiments to test his theory. He first crushed sixteen species of rocks, representing the whole series of formations from oolites to the hardest crystalline rocks. The second series of experiments, conducted on a very large scale, was to ascertain the coefficients of total contraction, between fusion and solidification at existing mean atmospheric temperature, of basic and acid slags analogous to melted rocks. Mallet thus finds that less than one-fourth of the heat annually lost by our globe is sufficient to account for its total annual vulcanicity. He then shows the accordance of his views with sundry facts of vulcanology and seismology. Finally, he accounts, on his theory, for the elevations on our moon's surface, and the evidence there of former volcanic energy, on a grander scale than on our planet.

The Vibrations produced by Various Explosives.—It is known that the instantaneous combustion of an explosive body is brought about by vibrations, independently of the agency of heat. An interesting inquiry here arises, whether these vibrations are identical for all explosives; and whether we can determine in advance the action of one explosive upon another. Two French savants, MM. Champion and Pellet, have investigated this subject, and the following is an account of their experiments: First, they set up an apparatus with eight gas-burners, to give "singing" flames, answering to the eight notes of the gamut. For the first experiment an anvil was placed at a distance of sixteen feet from this apparatus, and on it they placed in succession 0.03 grammes of iodide of nitrogen and fulminate of mercury, both enclosed in sacks of gold-beater's skin. The iodide, on being exploded, had no effect on the flames, while the fulminate caused the following flames to play: la, do, mi, fa, and sol. The conclusion is, that the vibrations produced by the two agents differ mutually, and further, that the vibrations caused by the fulminate act on some notes, passing over the others. In the second experiment the flame-apparatus and the anvil were placed twelve feet apart. It was now found that the iodide acted on the higher notes, whereas the fulminate affected the entire scale. But. if now we make each charge two decigrammes, and bring the anvil very close to the apparatus, the whole gamut will respond to both explosions. The third experiment was a repetition of the foregoing two, with this exception, that nitro-glycerine was substituted for iodide of nitrogen. The result did not show any difference between these two agents in their action on the flames; and yet it is known that there is a difference between their respective vibrations; for the fulminate will explode compressed gun-cotton, but nitro-glycerine will not, under identical conditions. No doubt, if a more perfect flame-apparatus, with a series of low notes, had been employed, a difference would have been manifested in the course of the experiment.

Economy of Fuel.—A self-feeding furnace is now in use in several English manufacturing towns, which is said to effect a great economy in the consumption of coal, besides possessing the additional advantages of burning all the refuse and completely consuming the smoke. A small and uniform amount of fuel, just enough to replace that consumed, is being constantly added to the fire, which is supplied with exactly as much air as is required to carry on the combustion in the most economical and effective manner. The apparatus is known as Vicar's Furnace, and is readily fitted to any kind of boiler, and to reverberatory furnaces of all descriptions.

Ammonia in Snow-water.—Dr. Vogel has an article on ammonia in snow-water in the Sitzungsberichte der mathematico-physikalischen Classe, of the Munich Academy of Sciences. The method employed by him is that of Schlösing, for estimating the amount of ammonia in arable soil. The results obtained were as follows, one litre (2.113 pints) being the unit: Freshly fallen snow, caught in a porcelain basin, at zero, gave 0.003 grammes; at -3° gave 0.002; at from -9° to -15° gave no ammonia. Water from snow which had stood 24 hours on a piece of manured garden-ground, contained 0.012 grammes; from snow which had stood on a meadow for 24 hours, 0.009 grammes; from a zinc roof, 0.004 grammes. Dr. Vogel observes that the quantity of ammonia in snow depends on a variety of conditions, and that, since snow, owing to its porosity, absorbs ammonia (and the same is true of snow-water), it is necessary to melt it in closed vessels. The amount of ammonia in snow is also dependent on the temperature at which it falls. At a rather low temperature (-15°), the author could not detect ammonia in snow.

Cultivation by Steam.—At an agricultural meeting, recently held in Scotland, some interesting statements were made respecting the origin, progress, and results of cultivation by steam in Europe. In 1855, a Mr. John Fowler, of Essex County, England, started his first steam-plough. Now, in Great Britain, there are single establishments for manufacturing steam-ploughs, so extensive that they furnish constant employment for not less than 1,200 men. In England, between 400 and 500 sets of steam-ploughs, held, some by companies and others by individual owners, are worked for hire, and are found to be a profitable investment. A tract of 500 acres, near London, so unproductive that it could not be rented for $3 per acre, was bought by an enterprising farmer, who removed the fences, under-drained, and, with a steam-plough, put the whole into grain-crops. Last year, after allowing 10 per cent, on the money invested in the land, his clear profits were $18,000. The soil he thus improved by deep steam-ploughing is a stiff clay that could not be profitably worked by horse-power. Another tract of 5,000 acres, that had been regarded as worthless, was bought by a farmer who ploughed it with steam-power to the depth of 3 feet, and was rewarded by crops of astonishing thrift. In Scotland, cultivation by steam is becoming general, and producing results equally marvellous. Joint-stock companies are investing in land and steam-machinery, and securing large dividends, while individual farmers have invested from $6,000 to $10,000 in steam-machinery with very profitable results. In Germany also steam-power is working a revolution in agriculture.

It was also stated that the Pasha of Egypt now employs on his extensive domain 400 steam-ploughs, and is building "on his farm" 400 miles of railway, and, for transporting and manufacturing the raw material produced, has ordered thirty locomotive-engines and $3,000,000 worth of sugar-machinery.

Perhaps the most successful cultivator by steam in America is Mr. E. Lawrence, of Magnolia Plantation, parish of Plaquemine, Louisiana. In a letter to the Agricultural Department, he speaks of the results of his trial of the steam-plough as follows:

"Two hundred and twenty acres of my cane-crop, 140 acres of which were plant-canes, and 80 acres first-year rattoons, were, I believe, as thoroughly ploughed and cultivated by steam as could be desired. The 80 acres of first-year rattoons, grown from the stubbles of the steam-ploughed cane planted in a similar manner last year, were barred off and well dug in the month of March, then subsoiled and cultivated by steam precisely as the plant-canes. The yield was over 2,500 pounds of sugar to the acre."

Mr. Lawrence closes his letter with the prophecy:

"Necessity will soon compel us to take a 'new departure.' The constant increase of immigration and population in the grain-growing States of our country will soon demand a better cultivation and increased production. In England, steam-ploughing has increased the yield of wheat from 16 bushels to 28 bushels to the acre.

"I do not believe the agricultural interest of our country can much longer turn a deaf ear to this last and greatest achievement of steam—its successful application to the cultivation of the soil. It has broken the yoke and lifted the burden which, for ages, held both man and beast in bondage, ameliorating their condition by making that which was most onerous easy and attractive; it has elevated labor, and dignified the plough."

Ozone by a New Process.—An apparatus for manufacturing ozone, patented by Dr. Loew, is mentioned in the Journal of the Franklin Institute. Some time since Dr. Loew observed that cold air blown through a flame is in part converted into ozone, and his apparatus is constructed with a view to turn this observation to practical account. It consists of a number of Bunsen burners, set up in a row, with an equal number of horizontal tubes at some distance above the burners. The cold air is blown through the tubes against the flames, and is then collected, in the shape of ozone, by a number of funnels placed on the opposite side of the flames. The ozone is to some extent contaminated by acetylen and nitrous acid.

The English Sparrow.—In a paper lately read before the Long Island Historical Society, by Mr. E. Lewis, Jr., and since published in the Brooklyn Union, we find the following interesting particulars concerning the importation into this country of the English sparrow, and the valuable service it has since rendered in clearing our city trees of insect-pests. As many are aware, the trees of Brooklyn some years ago were overrun by a species of caterpillar (Ennomos subsignaria), which, commencing when the leaves were young and tender, devoured them so rapidly that in a short time the branches were completely bared, making the tree an unsightly object, and greatly injuring its health and growth. The creatures also had the disgusting habit of suspending themselves from the limbs, whence they would drop in great numbers both upon the pavements and passing pedestrians. The maple, horse-chestnut, elm, and willow, were-thus attacked, and their destruction, or that of the caterpillars, was the alternative presented to the Brooklyn people. All sorts of expedients were proposed, and among them the introduction of the English sparrow. In spite of the failure of a previous attempt, a second was decided on, and in the fall of 1856 Mr. Thomas Woodcock, of Brooklyn, at the instance of the Brooklyn Institute, brought over from Manchester about a dozen sparrows, which were liberated in the following spring, when they flew away toward Brooklyn Heights. Nothing more was heard of them until the spring of 1858, when two pair were observed among the ivies of Grace Church, where it is probable that one or more nests were built, as during the summer young sparrows were noticed in the vicinity. Since that time their increase has been enormous, and almost solely through their agency the caterpillar nuisance has been completely removed.

According to Mr. Lewis, though feeding largely on seeds, and in cities upon almost every article of human food, the sparrows feed their young chiefly with worms, larvæ, the soft portions of coleoptera, moths, and other tender animal food. "By this means the number of devouring worms has been greatly diminished. The leaf-rolling caterpillar of the sycamore and the currant-bush are known to be taken and devoured by sparrows.

The inch-worm, too, is taken when young, as is the Japanese silk-worm, which feeds upon the ailantus-leaf.

"But the sparrows destroy the caterpillar family in a more effectual way than this. The large female moths of the Samia cynthia, or Japanese silk-worm, are seized for the eggs which they contain, torn to pieces, and the eggs devoured. So persistent are the sparrows in watching for and catching these moths, that a gentlemen in this city has been unable to raise either worms or moths unless protected from the birds.

"The moths, both male and female, of the inch-worm or tree-caterpillar, are eaten by sparrows. After seizing the moth, they will beat off its head and wings and feed to their young the soft parts of the insect.

"The destruction of the female moths arrests the increase of the caterpillars in a most effective way. But this is not all. We have referred to the sparrows feeding upon the eggs of moths after being deposited upon branches of trees. I have watched them at this frequently during the winter. These eggs are usually deposited in places where they are sheltered by raised or fractured fragments of the old bark, and are covered with a glutinous substance. The sparrow labors until fairly weary in breaking away the old bark and laying bare the eggs, which it removes with some difficulty, but which it nevertheless removes and devours.

"It is thus apparent that the chance for a full crop of caterpillars is small where sparrows are abundant. Indeed, the disgusting tree-caterpillar has disappeared from our city altogether."

The Brooklyn Institute has also attempted the introduction of English song-birds, but as yet with indifferent success. Among those brought over are the skylark, wood-lark, goldfinch, robin, and thrush. Some are known to have survived and produced young; but the general impression is that our winters are too severe for them to do well in this climate. "The sparrows," says Mr. Lewis, "seem to be well acclimated, although many have been found dead, after severe frosts and snow. It is evident that the severity of the climate, or some other cause, has somewhat arrested their growth, as persons, who are competent to judge, say they are a little smaller than in the English towns."

The Uses of Asbestos.—The mineral formation called asbestos—which term denotes rather a peculiar form assumed by sundry minerals than any particular species—is coming to be used very largely in practical mechanics and manufactures. The name asbestos, signifying indestructible, was given by the ancients to various amphibolic and augitic minerals, which occur in long, hair-like crystals, placed side by side, forming a fibrous mass. These crystals may easily be taken apart, and, as they are very elastic and pliant, have been used to manufacture a sort of cloth. The Romans used sometimes to envelop the bodies of their dead in a wrapping of this fabric, thus keeping their ashes separate from the ashes of the funeral-pile, for fire does not consume asbestos. We even read of napkins and articles of dress being made of this material—when soiled they were cleansed by being subjected to the action of fire. In ancient times the wicks of the ever-burning lamps in temples and shrines were often of asbestos, and at the present time the Greenlanders make a like use of it. A few years ago a Mr. Audesluys, proprietor of a large asbestos-deposit in the vicinity of Baltimore, commenced the manufacture of a paper containing about 30 per cent, of asbestos. Characters written on such paper, in common ink, are still legible after it has been subjected to the action of fire, and it is likely that advantage will be taken of this property of asbestos to manufacture a paper for important records. The great objection to all the asbestos paper so far made is its want of toughness, its friability. The Journal of the Society of Arts makes mention of an asbestos paper covering for roofs, but, as this mineral is not proof against moisture as it is against fire, experience alone could determine its value for that purpose. But, perhaps, the most important service yet rendered by asbestos is the furnishing us with a fire-resisting packing for piston and pump rods, the necks of revolving retorts, etc. Asbestos packing was used for the piston of a locomotive on the Caledonian Railway from July 27 to November 18, 1871, and was then as good as when it was first put in; while the best common packing would have lasted not above two months. It is better to make rings of asbestos, and put them on the piston, than to wind it round. There are very extensive deposits of this important mineral within the limits of the United States, that found on the eastern slope of the Green Mountains and of the Adirondacks being of the best quality for fineness and tensile strength. The fibre of New York and Vermont asbestos varies in length from two to forty inches, and resembles unbleached flax, when found near the surface; but when taken at a greater depth it is pure white, and very strong and flexible. It is found also in considerable quantities in the Tyrol, in Hungary, Corsica, and Wales.

British Scientific Expedition.—The enlightened liberality of the British Government in fitting out the steam-corvette Challenger, 2,306 tons, for a scientific voyage around the globe, receives the heartiest commendation from the English press, and from the whole world of science. The commander of the corvette, Captain Nares, R.N., is a distinguished seaman and explorer, and the second in command, Commander J. P. Maclear, R.N., is scarcely less eminent. We have space only for the names of a few of the scientific men who go out on this cruise. The director is Prof. Wyville Thompson, and he has under him J. J. Wild, of Zurich; J. Y. Buchanan, of Edinburgh, chemist; H. N. Mosely, naturalist; Dr. Von W. Suhm, do.; John Murray, Edinburgh University, do. The vessel has been thoroughly repaired and fitted for her work, with auxiliary screw, two engines of 400 horse-power each, boats, 40 dredges, etc. She carries an abundance of traps, harpoons, scientific apparatus, etc. The route of the vessel will probably be, first, to Gibraltar and the Bay of Biscay; thence to Madeira, St. Thomas, the Bahamas, Bermuda, and the Azores. From the Azores she will sail for Bahia, touching at Fernando Noronha. Thence she crosses to the Cape of Good Hope, from which point her course is southward to the Crozetts and Marion Islands and Kerguelen's Land. Thence her direction will still be southward, as far as the ice will permit, and then the vessel will steer for Sydney, New Zealand, the Campbell and Auckland Groups, Torres Straits, New Guinea, and New Ireland. A cruise among the Pacific Islands will probably take up a twelvemonth, when the expedition, passing between Borneo and Celebes, and visiting Luzon and its neighborhood, will make for Japan, there to remain for a couple of months. Kamtchatka will next be visited, whence a run will be made northward through Behring's Straits; thence through the Aleutian Islands, southward to Vancouver's Island, and so through the deep eastern region of the Pacific by Easter Island, and possibly to the Horn, through the Galapagos, and home. The voyage will take between three and four years, and from it results of the highest importance for science may be expected.

The Venomous Snakes of India.—A new book has been recently published by Dr. Fayrer on the venomous snakes of India, and the treatment of their poisonous bites. In Bengal the people suffer terribly from these reptiles. Dr. Fayrer says: "The frightful scourge of these animals is shown by the fact that the recorded deaths in 1869 were 11,416. But it is more than probable, considering the imperfection of Indian records, that 20,000 was nearer the true mortality." He has given a description of some new species of Hydrophidæ or poisonous sea-snakes which infest the Indian seas. These elegant creatures, with small heads and tiny jaws, will bite a man while bathing, inflicting an almost imperceptible wound, unnoticed at the time, but of which he dies in a day or two. About the most poisonous of the Indian reptiles is the cobra de capello, or hooded snake. The elevated skin of the back of the neck presents, when the animal is viewed in front, much the appearance of a hood. It is also sometimes called the spectacle snake, from a singular mark on the back of its neck, closely resembling a pair of old-fashioned spectacles. The cobra is some three or four feet long, of a pale, rusty-brown color above, and bluish or yellowish-white below. Its venom is extremely powerful, the bite sometimes causing death in less than two hours. This venom, though so exceedingly poisonous when introduced into the system, is comparatively harmless when taken into the stomach. It has a sharp taste, but no odor. Usually the cobra is a sluggish creature, and is easily killed. It seldom uses its fangs except for the purpose of obtaining food. One of its most disagreeable habits is an evident liking for the habitations of men, being frequently found near houses, and not rarely in the dwellings themselves.

In regard to cures for the bite of the cobra, Dr. Fayrer's experiments, no less than universal experience, bear testimony to the efficacy of the ligature, if applied promptly and tightly, near the wound, between it and the heart, and followed by excision of the wounded part and the application of the actual cautery. In case a finger or toe is bitten, amputation should immediately be performed at the next joint. Dr. Fayrer's principal snake-man was once bitten by an echis. Immediate excision and cauterization fortunately saved him. When the virus is once in the blood no known agent is capable of neutralizing it.

Some of Dr. Fayrer's results are extremely interesting and of great practical value. He finds that these snakes have the greatest repugnance to carbolic acid, which acts as a powerful and fatal poison to them. The practical advantage of using carbolic acid freely in and about houses in India must therefore be great. The practice of sucking a bite is not so absolutely safe as has been hitherto supposed. The poison may be absorbed through the buccal mucous membrane, or the lining membrane of the stomach, when it will produce its fatal effects.

The most venomous of these snakes seem to possess a perfect immunity from the poison of their own species, and considerable immunity from the poison of other species. Dr. Fayrer says: "In many of the various experiments I have performed, the cobra, daboia, and krait, did not appear to be able to poison themselves or each other. This result was not absolutely invariable, but sufficiently constant to be remarkable." On this point Dr. Fayrer's observations confirm those made by Dr. Russel. Snake-poison acts with most vigor on warm-blooded animals; birds die very quickly. The power of resistance is generally in proportion to the size of the animal, but not invariably so. For instance, a cat will resist the poison as long as a dog three or four times its size. Cold-blooded animals, fish, non-venomous snakes, and invertebrate animals, all die when bitten. There seems to be a certain difference in the action of the colubrine and viperine snakes. In poisoning by the colubrine snakes, the blood coagulates firmly, but in death by the viperine it remains permanently fluid—at least this was the case in many of Dr. Fayrer's experiments.

A New Fire-Escape.—At the International (London) Exhibition of 1872, Major E. R. Wethered exhibited a fire-escape, consisting of a canvas cradle, with a guard-band to be passed beneath the arms, a strong rope, and a pulley furnished with a clamp, which can be worked by the hand, as the fugitive descends. At an alarm of fire, the sashes of the window are to be thrown into close correspondence at the top. The rope is then thrown around them at one side and hitched with a hook. The lateral pull of the weight will jam the sashes in the frame. The pulley, having five friction rollers, between which the rope runs sinuously, and a clamp worked by lever and handle, is fixed a little above the cradle. The free end of the rope is coiled on a reel, and is thrown out of the window, unwinding as it falls. In addition to the clamp, the descent of the cradle may be governed by the left hand of the fugitive, running along the rope.

Necessity of Carefulness in Old Age.—An old man is like an old wagon; with light loading and careful usage it will last for years; but one heavy load or sudden strain will break it, and ruin it forever. Many people reach the age of fifty, sixty, or even seventy, measurably free from most of the pains and infirmities of age, cheery in heart, and sound in health, ripe in wisdom and experience, with sympathies mellowed by age, and with reasonable prospects and opportunities for continued usefulness in the world for a considerable time. Let such persons be thankful, but let them also be careful. An old constitution is like an old bone—broken with ease, mended with difficulty. A young tree bends to the gale, an old one snaps and falls before the blast. A single hard lift; an hour of heating work an evening of exposure to rain or damp; a severe chill; an excess of food; the unusual indulgence of any appetite or passion; a sudden fit of anger; an improper dose of medicine—any of these, or other similar things, may cut off a valuable life in an hour, and leave the fair hopes of usefulness and enjoyment but a shapeless wreck.