Popular Science Monthly/Volume 8/December 1875/Miscellany
United States Board for testing Iron and Steel.—We have already (in the July number of the Monthly) called attention to the researches proposed to be made by the United States Board for testing Iron and Steel, and recur to the subject in order to stimulate those of our readers who may be in possession of facts bearing on the inquiry to communicate with the chairmen of the various committees into which the board has been divided. These committees are fifteen in number. The committee on abrasion and wear, chairman, R. H. Thurston, has to examine and report upon the abrasion and wear of railway wheels, axles, rails, and other materials. Another subject of investigation by this committee is the wear of tools under the various conditions of workshop practice. The committee on armor-plate, chairman, Lieutenant-Colonel Q. A. Gillmore, U.S.A., will make tests of armor-plate, and collect data derived from experiments already made to determine the characteristics of metal suitable for such use. A. L. Holley is chairman of the committee on chemical research, whose duty it is to plan and conduct investigations of the mutual relations of the chemical and mechanical properties of metals. The committee on chains and wire-ropes, whose chairman is Commodore L. A. Beardslee, U.S.N., is charged to determine the character of iron best adapted for chain-cables, the best form and proportions of link, and the qualities of metal used in the manufacture of iron and steel wire-rope. The committee on corrosion of metals, W. Sooy Smith, chairman, is to investigate the subject of corrosion of metals under the conditions of actual use.
The committee on the effects of temperature, chairman, R. A. Thurston, will investigate the effects of variations of temperature upon the strength and other qualities of metals. That on girders and columns will arrange and conduct experiments to determine the laws of resistance of beams, girders, and columns, to change of form and to fracture. Two committees on iron, wrought and cast, chairmen, Commander Beaslee and Lieutenant-Colonel Gillmore, will examine and report on the mechanical and physical properties of wrought and cast-iron. The committee on metallic alloys, chairman, Prof. Thurston, is to make experiments on the characteristics of alloys and to investigate the laws of combination. That on orthogonal simultaneous strains, chairman, W. Sooy Smith, will experiment on such strains with a view to the determination of laws. W. Sooy Smith is also chairman of the committee of physical phenomena, who will investigate the physical phenomena accompanying the distortion and rupture of materials. The committee on reheating and rerolling, chairman. Commodore Beaslee, will observe and experiment on the effects of reworking metals; of hammering as compared with rolling, and of annealing metals. A committee on steels produced by modern processes, A. L. Holley, chairman, will investigate the constitution and characteristics of steels made by the Bessemer, open-hearth, and other modern methods. Finally, the committee on steels for tools, chairman, Chief-Engineer D. Smith, U.S.N., is directed to determine the constitution and characteristics and the special adaptations of steels used for tools. Each of these committees has issued a circular, more particularly defining the researches in which it is engaged; they can be obtained from the secretary of the board, Prof. Thurston, Stevens Technological Institute, Hoboken, New Jersey, or from the respective chairmen.
Stanley's Expedition.—Letters have been received by James Gordon Bennett, of this city, from Henry M. Stanley, commander of the expedition fitted out for the exploration of the interior of Africa by the proprietors of the New York Herald and the London Telegraph. The letters were written at a village called Kagehyi, on the extreme southern shore of Victoria Niyanza. The expedition reached that point on February 27, 1875, after an arduous march of 103 days from the sea-coast. There were in the expedition, as soldiers and carriers, over 300 men, all native Africans except five, the commander and four Englishmen. For the first 175 miles Stanley followed Livingstone's route nearly due west, but, having reached the western frontier of Ugogo, he quitted the beaten path, and, for the remaining 550 miles, his line of march lay steadily in a northwestern direction. A few days later, the guides who had been hired in Ugogo deserted, and the trail which the expedition had been following was lost in a labyrinth of elephant and rhinoceros tracks. Still continuing his march to the northwest, Mr. Stanley's men, with great difficulty, forced and cut their way through a dense jungle on the third day after the guides had deserted. The following two days' march was very trying to the men, who suffered from hunger and thirst, and a halt was ordered until provisions could be got from Suna, a place distant nearly thirty miles. While waiting, the men had two scanty meals of gruel, which was made in a sheet-iron trunk. At a point 400 miles from the sea, Edward Pocock, one of the four Englishmen, died of typhoid fever. Thirty of the blacks were on the sick list, and six had died at Suna. The most stirring incident of the entire march to Victoria Niyanza was the three-days' battle with the people of the Lewumbu Valley. The savages were soundly whipped, and many of their villages burned. The plunder of the villages supplied the force with provisions for six days. Stanley lost twenty-one men in this little war; and when, three days later, he numbered the expedition, it was found that there remained only 194 men, and the number was still further reduced before he reached the shores of Victoria Niyanza. On his arrival at Kagehyi, he had only 166 native soldiers and carriers, and three white men.
The second letter gives an incomplete account of aof the coast of Victoria Niyanza. This was made in a cedar boat, which had been carried in sections from the sea-coast. Mr, Stanley, in this boat, the Lady Alice, surveyed all the coasts of the lake, sailing over 1,000 miles in fifty-eight days. In the letter which we call the second, Mr. Stanley mentions a previous letter which he wrote at Mtesa, on the north shore of the lake, latitude 0° 20' north, longitude 33° east. There he met Colonel Linaut de Bellefonds, of Gordon's staff, and gave him a letter for transmission to England. Strange to say, this letter has not yet reached its destination, while two other letters, one of them of later date, and which were sent via Unyanyembe to Zanzibar by caravan, have been received. A map accompanies the "second" letter. This map, being based on actual survey, decides the question, long discussed, whether Victoria Niyanza is one lake or a multitude of lakes. It is seen to be one vast sheet of water, with length and breadth nearly equal, but with its largest diameter lying from northeast to southwest. Its extreme northern limit is in latitude 0° 30' north, and its extreme southern limit in latitude 2° south. East and west it reaches longitude 34° 30' east, and 31° 50' east, respectively. During Stanley's absence from Kagehyi, Frederick Barker, one of his English followers, died there of fever. The newspapers in whose service Mr. Stanley is engaged ought to have attached to his staff a secretary possessed of some little literary tact. Mr. Stanley's own communications are verbose to the last degree: they give no clear idea of the nature of the countries visited; their inhabitants; how the expedition obtained supplies, etc. The two letters already published purport to give the history of about six months, but they are in volume equal to about one-fourth of Cæsar's famous memoirs of the Gallic War, which extended over nine years.
Putrefaction arrested by Pressure.—A communication to the Paris Academy of Sciences, by M. Paul Bert, on the "Influence of Air-Pressure on Fermentation," a summary of which appears in the Academy, states that a piece of meat placed in oxygen, with a pressure of twenty-three atmospheres, remained from July 26th to August 3d without putrescence or bad odor. It consumed in that time 380 cubic centimetres of the gas. A similar piece, suspended in a bell-glass full of air at the ordinary pressure, acquired a bad smell, consumed all the oxygen, amounting to 1,185 centimetres, and was covered with mould. Another trial was made with oxygen at a pressure of forty-four atmospheres; no oxygen was absorbed between December 19th and January 8th, and no bad odor was exhaled. M. Bert could eat cutlets preserved in this way for a month, and found them only a little stale in flavor. After being exposed to air at this pressure, allowing an escape so that only normal pressure remained, the meat suffered no damage, provided the bottle was well corked, so that no external germs could enter. Thus it appears that the micro-ferments which cause fermentation can be killed, when they are moist, by a sufficient tension of oxygen. Fermentations of milk and wine are arrested by high pressure, and fruits keep sound. Diastase continues to act as a ferment, and bodies of this description preserve their properties indefinitely if retained under pressure.
Meeting of the French Association for the Advancement of Science.—The President of the French Association for the Advancement of Science, M. d'Eichthal, delivered an address at the opening of the Nantes meeting, on the connection between pure science and the various methods employed to satisfy the wants of humanity. The text of this address has not yet come to hand, but we give herewith the summary of it, which is published in Nature. It would be almost impossible, he said, to enumerate all the branches of human activity which owe their success to the researches of pure science—hygiene, medicine, surgery, the fine arts, mechanics, industry in all its branches, mining, metallurgy, textile industries, lighting, warming, ventilation, water-supply, etc. He then referred in detail to several examples of the influence which the results of science have had upon progress in the arts, with the motive forces of water, air, and steam, mentioning a multitude of names of men eminent in pure science, from Pascal and Boyle down to Faraday and Sir William Thomson, upon the results of whose researches the great advances which have been made in machinery of all kinds have depended. He then spoke of electricity in connection with the names of Oerstedt, Ampere, Faraday, Becquerel, and Ruhmkorff; passing on to speak, at some length, of the steam-engine in its various forms, of the progress which, by means of scientific research, is being made in its construction and its uses, and of the great services which this powerful application of a scientific discovery renders to man. M. d'Eichthal advocated the establishment of local centres of culture as the best counterpoise to that over-centralization to which France owes so many of its social misfortunes. "In our time," said he, "science, history, and literature, have great wants. Libraries, lecture-halls, laboratories, costly materials, instruments numerous and expensive, are indispensable to pupils for learning, and to teachers for carrying on their researches; it is by putting, on a large scale, these resources at their disposal, that we can attract and fix in our midst men eminent in all branches of human knowledge."
Thermo-diffusion.—In the Physical Section, M. Merget stated the results of his researches on the thermo-diffusion of porous and pulverulent bodies in the moist state. A "thermo-diffuser" is any vessel of porous material, filled with an inert powder, into which is plunged a glass or metal tube pierced with holes. On heating this apparatus, after it has been wetted, water-vapor is given off copiously, passing through the porous substance, while dry air passes through the apparatus in the contrary direction, escaping through the tube. If we stop the mouth of the tube, there is produced a pressure amounting to three atmospheres at the temperature of a dull-red heat. If the pulverulent mass or the porous body ceases to be moist, all passage of gas is stopped. These facts the author does not explain, but he shows that De la Rive's explanation cannot be accepted. M. Merget is satisfied that he has here to do with a thermo-dynamic phenomenon. Thermo-diffusion must play an important part in the gaseous exchanges of vegetal life, as the author showed by taking a leaf of Nelumbium as a thermo-diffuser. M. Merget also offered some observations on the Respiration of Plants. He said: If under the influence of light, however feeble, we plunge into water containing carbonic acid, an aerial, or, better, an aquatico-aërial leaf, passing the extremity of the petiole into a test-tube, where the pressure will be a little less than that of the atmosphere, then there will form around the stomata of the leaf an atmosphere of carbonic acid, and oxygen will be discharged from the end of the petiole. The more intense the light, the more rapid the disengagement of oxygen, and under the influence of solar light a single leaf of Nuphar has yielded as much as five cubic centimetres of oxygen per minute—corresponding to the fixation of one gramme of carbon in ten hours. But, if we preserve all the other conditions, abstracting only light, the bubbles of carbonic acid at the stomata disappear, the cell fills with water, and ceases to respire. Thus it is in the gaseous state that carbonic acid is decomposed by the chlorophyll; and, according to the author, chlorophyll possesses the property of directly breaking up gaseous carbonic acid into its elements, carbon and oxygen.
From all this it follows that the passage of carbonic acid through the stomata is a purely physical phenomenon, not vital—a phenomenon of thermo-diffusion.
Religion of the Canarians.—The superstitious practices in use among the primitive Canarians was the subject of a paper read by Señor Chil y Naranjo. On Gran Canaria, he says, the natives believed in an infinite being, Alcorac or Alchoran. Him they worshiped on the summits of mountains, as also in little temples called almogaren. Their priests were women, and were bound by a vow of chastity. The sacred places were also asylums for criminals. The Canarians believed in the existence of an evil spirit, Gabio. On Teneriffe the Guanchos worshiped Achaman, and used to assemble in consecrated places for common prayer. On Palma, the name given to the Supreme Being was Abara. In all the islands homage was rendered to the emblems of fecundity and to the four elements. Their sacrifices were such as would be esteemed most precious by a pastoral people. They attributed will to the sea; it was the sea that gave them rain. In time of drought they scourged the sea, and implored the aid of Heaven with great ceremony.
Microcephaly.—Dr. Laennec exhibited a microcephalous idiot, aged fourteen years, of the male sex. This child is entirely unconscious of his own actions, and his intellectual operations are very few in number and very rudimentary. His language consists of two syllables, oui and la, and he takes an evident pleasure in pronouncing them. He takes no heed in what direction he walks; he would step off a precipice or into a fire. Dr. Laennec called attention to the idiot's hands; the thumbs are atrophied and cannot be opposed to the other fingers. The palms of the hands have the transverse creases, but not the diagonal—the result of the atrophy of the thumbs. Hence the hand resembles that of the chimpanzee. The dentition too is defective. Though fourteen years of age, the child has only twelve teeth.
The Booted Eagle.—M. Louis Bureau stated the results of observations on varieties of the booted eagle (Aquila pennata), the smallest European bird of the eagle tribe. M. Bureau, having examined a number of broods of the booted eagle, says that all the varieties of this species may be reduced to two chief types, white and black. In pairs, both of the sexes sometimes belong to one type, but they more usually are of different types. In fact M. Bureau has found in the same forest, and at but little distance from one another, two pairs, in one of which the male was black, and the female white, and, in the other, the male white and the female black. As a rule, the young birds are either all black or all white. But in one nest, containing two chicks, the one was white, the other black. From this it follows that these variations of color are not correlated with the age of the bird.
St. Louis Academy of Science.—At a recent meeting of the St. Louis Academy of Science, Prof. Riley read a paper on the canker-worm, in which he says that two sorts have hitherto been confounded under this name, that are not only specifically, but he thinks generically, distinct. They present important structural differences in the egg, the larva, the chrysalis, and the moth states; and also differ in the time of their appearance: one species rising from the ground mostly in early spring, the other mostly in the fall. Both attack fruit and shade trees, but, while the spring sort is common and very injurious in the apple-orchards of the Western States, the other is rare there, and most common in the elms of New England. To combat the former, or spring species, fall ploughing under the trees, which breaks up their fragile cocoons that lie secreted in the soil, and in early spring scraping the trunks of the trees where their eggs are lodged in the crevices of the bark, are recommended. These measures fail with the fall sort, and, in the abstract of the paper now before us, nothing is suggested to take their place.
At the same meeting Prof Riley also presented a paper giving an account of some recent experiments with the grape phylloxera, undertaken for the purpose of determining when the winged female deposits her eggs. He built a tight gauze house six feet high and four square over a Clinton vine. The house was built so as not to permit even so small an insect as the winged phylloxera to get in or out, and the vine was trimmed so that but few branches and leaves remained to be examined. Into this inclosure he brought an abundance of infested roots, and from these obtained a supply of the winged females, confined where he could watch their ways. The result of these observations is that, as has been surmised, the eggs are often laid in crevices on the surface of the ground, but still more often on the leaves, attached generally by one end amid the natural pubescence of the under surface; and, while heretofore all efforts to artificially hatch the progeny from these eggs have failed, Prof Riley has this year succeeded in hatching them, and presented a tube filled with living females.
Condensed Beer.—A process for condensing beer, recently patented in England, is described as follows in the English Mechanic: Beer or stout is taken at any stage of fermentation, though the process is better applied when it is fit for drinking, and evaporated in a vacuum-pan until it becomes a thick, viscous fluid. The alcohol and water of course pass off in vapor, which, in turn, is condensed in a receiver, and the alcohol recovered by redistilling the liquid. This alcohol may be mixed again with the condensed beer. By this process of condensation, the beer is reduced to one-eighth or one-twelfth of its original bulk, and, as the fermentation is suspended by the heat employed, the condensed mixture will keep in any climate for any length of time. The process of reconverting the mixture into beer is also a simple one, consisting merely in adding the bulk of water originally abstracted, and setting up fermentation again by the use of a small quantity of yeast or other ferment. Within forty-eight hours the beer may be drawn from the tap for use, or bottled in the ordinary way; or, without using any ferment, the beer may be bottled, and charged with carbonic-acid gas
Is Consumption contagious?—Some experiments and observations recently made, on the transmission of tuberculosis or phthisis from one animal to another, are worthy of note, as indicating one fruitful source of pulmonary disease. Thus it has been found that when an animal with tuberculated lungs is made the yoke-fellow of a perfectly healthy animal, and the two are housed and fed together, so as to inhale one another's breath, the one which at first was sound, before long exhibits the symptoms of tuberculosis. Again, Krebs has produced tuberculous by giving animals milk from those which were diseased. In addition to rabbits and Guinea-pigs (which animals are very susceptible to the artificial production of the malady), he accidentally induced the disease in a dog by feeding it with the milk of a cow in the last stage of phthisis. As a result of his observations, he asserts that tubercle virus is present in the milk of phthisical cows, whether they are slightly or gravely affected. On vigorous subjects such milk may produce no injurious effects, but the case is likely to be different with children, and those of enfeebled constitution. Similar effects may result from eating the flesh of animals affected with tubercle, and by inoculation with the virus. Thorough cooking of milk and flesh-meat neutralizes their injurious action.
Continuity of the Guano-Deposits.—Are guano-deposits of recent formation, or do they date from a geological epoch prior to the present? The latter opinion has been held by many eminent scientific men, among them Humboldt. The observations of Boussingault, however, go to prove the recent origin of these deposits. One fact, cited by Boussingault in support of this theory, is the existence in the guano of the bodies of birds with their soft parts preserved. These remains have been attentively studied by Barral, who shows that they belong to existing species. One of these birds was identified as a species of cormorant, which is common on the coast of Peru. Then there is a sort of gannet, which frequents all parts of the Pacific; a species of petrel; and finally the penguin. There are also fragments of the bones of mammals belonging to the eared seal. All these species extend very much farther south than the guano islands, and if deposits of guano have not been found in the colder islands of the Pacific Ocean, it is probably because the rainfalls have removed the birds' excrement, which in other localities has accumulated.
Centennial Display of Mineral Products.—It is the intention of the Department of the Interior to have at the Centennial Exhibition a collection of the mineral products of the United States. The Smithsonian Institution has been charged with the work of making this collection, and accordingly Prof. Joseph Henry has published a circular, inviting the cooperation of mine-owners, superintendents, engineers, geologists, and all others who are able to contribute to the attainment of the object in view. "Such a collection," says the circular, "formed and arranged with skill and discrimination, is important, for the purpose of presenting a general view of the extent and variety of these productions at the Exhibition, and will constitute a portion of the National Museum, where it will be permanently arranged after the Exhibition." Letters of inquiry, with regard to this collection of minerals, should be addressed to Prof. Y. P. Blake, New Haven, Conn.
Resuscitation of the Drowned.—The Massachusetts Humane Society has published the following plain directions for saving the lives of persons rescued from drowning after they have become insensible:
1. Lose no time. Carry out these directions on the spot. 2. Remove the froth and mucus from the mouth and nostrils. 3. Hold the body, for a few seconds only, with the head hanging down, so that the water may run out of the lungs and windpipe. 4. Loosen all tight articles of clothing about the neck and chest. 5. See that the tongue is pulled forward if it falls back into the throat. By taking hold of it with a handkerchief, it will not slip. 6. If the breathing has ceased, or nearly so, it must be stimulated by pressure of the chest with the hands, in imitation of the natural breathing, forcibly expelling the air from the lungs, and allowing it to reënter and expand them to the full capacity of the chest. Remember that this is the most important step of all. To do it readily, lay the person on his back, with a cushion, pillow, or some firm substance, under his shoulders; then press with the flat of the hands over the lower part of the breastbone and the upper part of the abdomen, keeping up a regular repetition and relaxation of pressure twenty or thirty times a minute. A pressure of thirty pounds may be applied with safety to a grown person. 7. Rub the limbs with the hands or with dry cloths constantly, to aid the circulation and keep the body warm. 8. As soon as the person can swallow, give a tablespoonful of spirits in hot water, or some warm coffee or tea. 9. Work deliberately. Do not give up too quickly. Success has rewarded the efforts of hours.
Trout-Culture.—In a communication to Forest and Stream, Mr. M. Goldsmith, one of the Fish Commissioners for Vermont, states the results of an experiment in trout-culture, which, if verified, cannot fail to have a great influence on the development of artificial fish-breeding. Mr. Hale, of the town of Rutland, has for some months fed the trout in his ponds with bread made of Indian-corn. He adds to the meal a little sugar or molasses of the cheapest sort, and it is stated that the trout eat the bread thus prepared with as much avidity as they do chopped liver or other animal food. The fish are in good condition, though they do not grow quite so rapidly, perhaps, as they would on a flesh diet. Their flesh is firm and has a fine flavor. This discovery, adds Mr. Goldsmith, makes trout-culture not only possible in localities where it would not otherwise be practicable, but in all cases more economical. Whether the vegetable diet can be rigidly practised, is a matter for further inquiry. Even if the result should prove that a certain quantity of animal food is necessary to the most perfect health of the trout, it is still a fact of great value that they can live, and grow, and fatten, on a vegetable diet.
Changes in the Skin of Fur-bearing Animals.—The obvious difference between the fur of animals in summer and in winter is found by Dönhoff to be associated with an equally striking difference in the texture and thickness of their skin. Thus, the average weight of an ox-hide in winter is seventy pounds; in summer, fifty-five pounds; the hair in winter weighs about two pounds, and in summer about one pound; leaving fourteen pounds to be accounted for by the proper substance of the skin. These differences are quite as decided in fœtal animals as in adults. Calves born in winter have a longer and thicker coat than those born in summer; moreover, there is a difference of more than a pound in the weight of their skins after the hair has been removed. Similar facts may be observed in the case of goats and sheep. That these differences are not to be ascribed to any corresponding change in the diet and regimen of the parent animals, is proved by the fact that they are equally manifest in the young of individuals kept under cover, and on the same food all the year round.
Intensity of Solar Radiation.—In a letter to Ste.-Claire Deville, Soret alludes incidentally to some recent optical observations which show the great intensity of solar radiation. If we look at an ordinary flame through plates of glass colored blue with cobalt, we observe that with a certain thickness of glass the flame presents a purple color, as the glass transmits the extreme red rays, and the highly-refrangible blue and violet rays, while it intercepts the rays of intermediate refrangibility. If the source of light have a high temperature, and therefore emit highly-refrangible rays, the flame appears blue, and it requires a number of superposed plates in order to develop the purple tint. Thus it was found that, at the temperature at which platinum fuses, two plates would give a purple color; at the fusion of iridium three plates were required, and on observing the sun the purple color was not developed even with half a dozen plates.
Extinction of Animals in Rodriguez.—Alphonse Milne-Edwards, in a communication to the Paris Academy of Sciences, shows from documentary evidence that the solitaire and the other gigantic birds of the Island of Rodriguez became extinct between 1730 and 1760. Reports addressed to the Compagnie des Indes show that the island was regarded as a sort of provisioning-store, not only for the Isle of Fiance and the Island of Bourbon, but also for the ships frequenting these parts. One object of their visits was the collection of land-tortoises, and efforts were made by the compagnie to put some restrictions on this business. The land-tortoise has long since disappeared from the island. As for the great birds of Rodriguez, owing to their undeveloped wings they were easily captured, while the delicacy of their flesh caused them to be much sought after.
Terrestrial Radiation.—Prof. Thiselton Dyer, at a recent meeting of the British Horticultural Society, made the following communication upon the phenomena of terrestrial radiation and its effects on vegetation, basing his remarks upon the observations of Buchan. The effects of radiation, he said, are at the maximum when the air is calm and very dry, and its temperature rather low. If, however, the cold air produced through the influence of terrestrial radiation be allowed to accumulate close to the ground, no small amount of damage may be done by a comparatively light frost. On sloping ground such accumulation of cold air cannot go on, because, cold air being heavier than air which is warmer, as soon as the air in immediate contact with sloping ground is cooled it flows down to a lower level, just as water would do, and its place is taken by the warmer current of air immediately above. In this way a higher night temperature is maintained in situations where the ground slopes down to lower levels, and accordingly such situations should be chosen for those plants which, at any stage of their growth, are peculiarly liable to be injured by frost. If the air be not calm, but a wind—even a slight wind—be blowing, the different layers of air are thereby mixed; and thus the air cooled by contact with the cold ground is not suffered to rest thereon, but is mixed with the air above it, and the temperature is thus prevented from falling as low as it otherwise would.
Trapping Wild-Turkeys.—There is a touch of cynic humor in a peculiar mode of trapping wild-turkeys in Virginia, as described by a writer in Forest and Stream. Having discovered one of the familiar haunts of the birds, the trapper digs a trench eighteen inches deep and about as wide, and four or five feet long, with a slope from the outer end deepening to the middle. A pen of fence-rails is now built, the first rail being laid across the middle of the trench; this is the width of the pen, and it has the length of two rails. It is built to the height of eight or ten rails and covered over with the same. Some grain is now scattered around and in the trench, and a large quantity within the pen. The turkeys get on the train of bait leading into the pen, and with heads down, eagerly picking up the grain, they go under the sill-rail in quest of food. Half a dozen or so will perhaps enter in thus, and then they find themselves imprisoned. They go round and round to find an exit, but it never occurs to them to look down, and thus they never find the passage through which they entered.
Rationale of the Welding of Iron.—The welding of iron and the regelation of water are very ingeniously traced to the same cause by Mr. M. Jordan. Faraday was the first to observe the phenomenon afterward called "regelation." By this term we imply that when two pieces of ice are pressed even very gently together, the temperature being just below zero, they at once become welded to each other. Of this Thompson offers the following explanation: For all bodies which, like water, have the property of diminishing in volume as they liquefy, pressure, which tends to bring the molecules closer together, lowers the temperature of fusion. Consequently, when two pieces of ice are rubbed against each other, fusion takes place between the surfaces in contact, at a temperature below zero. But as soon as the pressure ceases solidification is again produced, and the pieces are welded together. With iron, observes Mr. Jordan, the case is the same. The two pieces to be welded together are brought to a white heat, i. e., more or less near to the fusing-point. The repeated blows of the hammer, or the pressure of the rolls, lowers the point of fusion, causing a superficial liquefaction of the parts in contact, and thus welding the masses together; and this because, like water, iron dilates in passing from the liquid to the solid state. "The careful comparative study of these two bodies," adds Mr. Jordan, "even though at first sight apparently so dissimilar, cannot fail to furnish results of great interest to the metallurgist. The work of the puddler is also based upon the same phenomenon as that of welding. When the puddler forms his ball in the furnace, it is done by rolling together or aggregating the crystals of iron as they form in the mass of melted iron and slag. In other words, the semi-fused crystals are welded or regelated together by the mechanical action of the puddler."
Propagation of Waves in Liquids.—At a late meeting of the Paris Physical Society, M. Marey exhibited certain apparatus which he has employed in studying the propagation of waves in liquids. His method consists in producing, at a given point in an India-rubber tube filled with water, a sudden compression or dilatation, either by pressing on the walls of the tube, or by means of a piston. Small clips arranged along the tube at equal distances from each other signal the passage of the wave of compression or dilatation to a registering apparatus. In this way M. Marey has found that the velocity of the waves decreases with the size and increases with the elasticity of the walls. The density of the liquid has also some effect, but this is not of sufficient importance to be taken into account in applying this method of observation to physiology.
Restoration of Faded Writings.—Very often paper and parchment documents are illegible owing to the ink with which they were written having faded. The Revue Industrielle gives a very simple method of restoring to the ink its color. It is as follows: First, wet the paper and then pass over it a brush dipped in a solution of ammonia sulpho-hydrate. The writing quickly reappears, the characters being of a very deep black color. In parchment this color is permanent, but in paper it is only temporary. Old parchment chronicles in the Nuremberg Museum which have been treated in this way are now as legible as when first they were written, though before the application of the process all color had faded out of the ink. The rationale of the process is, that by the action of the ammonia sulpho-hydrate, the iron of the ink is changed into a black sulphuret.
An Optical Illusion.—St. Simon, in his famous "Mémoires," describing the personal appearance of the twelfth Duke of Albuquerque, characterizes his hair as "coarse and green." The question here arises, Was the duke's hair really of this color, or was St. Simon the victim of an optical illusion? That the latter was in all probability the fact, is shown in a communication made to the Paris Academy of Sciences by the venerable M. Chevreul, "the oldest student in France." On the day when the Duke de St. Simon saw Albuquerque, the latter wore a bullock's-blood coat of coarse cloth, with buttons of the same, and his hair hung down on his shoulders. "Now," says Chevreul, "if we take hairs of a certain color, and arrange them on a red ground in parallel lines, making a small ribbon of them, and place beside them exactly similar hairs on a white ground, the former relatively to the latter will appear green. If for white we substitute orange, the hairs on the red ground will assume a bluish tint; if violet, a yellow tint; if green, a ruddy tint; if blue, an orange tint; if violet, a greenish yellow; and, finally, if we substitute black for the white ground, the hairs on the red ground will become whitened. In short, if we look at a broad surface of one simple color, we see it and appreciate it absolutely. If we see it in Juxtaposition with another color, or, still better, at the centre of a broad surface of another color, we see it relatively, and the sensation produced by it will be quite different."
A Rat in the Telegraph Service.—A telegraph-inspector in England recently pressed into his service a rat under the following peculiar circumstances: It was necessary to overhaul a cable of wires inclosed in iron tubes. A certain length of the cable had to be taken out of the tube, and the men commenced hauling at one end without having taken the precaution to attach to the other a wire by which it might be drawn back into the tube after inspection and repairs. The question arose, how the cable was to be restored to its proper place; and here the ingenuity of the inspector was manifested. He invoked the aid of a rat-catcher, and, provided with a large rat, a ferret, and a ball of string wound on a Morse paper drum, he repaired to the opening in the tube. The "flush-boxes" were opened, and the rat, with one end of the string attached to his body, was put into the pipe. He scampered away at a racing pace, dragging the twine with him until he reached the middle of the length of pipe, and there stopped. The ferret was then put in, and off went the rat again until he sprang clear out of the next flush-box. One length of the cable was thus safe, and the same operation was commenced with the other; but the rat stopped short a few yards in the pipe and boldly awaited the approach of the ferret. A sharp combat here commenced, and it was feared that one or both of the animals would die in the pipe. But, after sundry violent jerks had been given to the string, the combatants separated; the ferret returned to his master, and the rat, making for the other extremity of the pipe, carried the string right through, and so relieved the inspector from his anxiety.
Behavior of Metals with Hydrogen.—From researches carried on conjointly by Messrs. Troost and Hautefeuille, and reported to the French Academy of Sciences, it appears that potassium, sodium, and palladium, combine with hydrogen, while a considerable number of other metals merely dissolve this gas. Iron, nickel, and manganese, offer striking analogies in their behavior with hydrogen at different temperatures. The facility with which they absorb or give off hydrogen gas depends greatly on their physical condition. An ingot of pure nickel gave out in a vacuum, at a red heat, one-sixth of its volume of hydrogen. Pulverulent nickel gave out 100 times its volume, and remained pyrophoric after the escape of the hydrogen. An ingot of cobalt gave out one-tenth of its volume, electrolytic laminæ of cobalt 85 times their volume, and pyrophoric cobalt powder 100 times. It also remained pyrophoric after the loss of the hydrogen. Soft iron in ingots gave off one-sixth of its volume, and gray cast-iron more than half. Electrolytic laminæ of iron gave off 260 volumes.
Disproportion of the Sexes in Germany.—The proportion of males to females in the population of the German Empire appears to be steadily declining. In 1855 the excess of females over males in what is now the German Empire was 348,631, which declined in the following nine years of peace to 313,383 in 1864. At the end of 1866, that is, after the Schleswig-Holstein and Austrian Wars, the excess was 471,885. In December, 1871, the effects of the war with France was shown in au ascertained surplus female population of 755,875. Thus in the seven years, from 1864 to 1871, the excess of females over males in the German population had increased by no less than 14 per cent. Although no inconsiderable portion of this loss to the German male population is due to actual slaughter on the battle-field, it is undoubtedly caused principally by emigration. Even if emigration could now be checked, it would take more than one generation to restore the proportion between the two sexes in Germany to what it was ten years ago.
Reduction of Obesity.—As a means of counteracting a tendency to obesity, and for reducing that habit after it has been established, Philbert recommends a mode of treatment somewhat different from that proposed by Banting. He interdicts the use of carbonaceous food as far as possible, and would augment the amount of oxygen. Hence the food must be nitrogenous, varied with a few vegetables containing no starch, and some raw fruit. The temperament, however, must be taken account of; the lymphatic should have a "red" diet—beef, mutton, venison, pheasant, etc.; the sanguine a "white" diet—veal, fowl, oysters, etc. Vegetables not sweet or farinaceous may be taken. Coffee without cream, and tea with little sugar, may be used. Sugar, butter, cheese, potatoes, beans, etc., are forbidden. In addition to these dietetic precepts, Philbert recommends favoring the action of the skin, supporting the walls of the abdomen by the use of a tight roller, and taking exercise freely. As a purgative, intended to promote the success of the treatment, the author recommends waters containing sulphate of soda.