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Popular Science Monthly/Volume 49/August 1896/Fragments of Science

Fragments of Science.

Nutritive Value of Meats.—In a recent article on the value of meats as food, in the Dietetic and Hygienic Gazette, Prof. R. H. Chittenden corrects several very widespread misconceptions regarding meat values. He says: "The cheapest food is that which supplies the most nutriment for the least money. The well-known maxim that 'the best is the cheapest' is not true of foods, for the term best in this connection is ordinarily applied to that which has the finest appearance, the finest flavor, the most tender structure, etc. Thus, there is no more nutriment in a pound of proteid from tenderloin steak than in the same weight of proteid from the neck or shoulder, and yet note the great difference in cost. The tenderloin will not supply the body's needs one particle better than the coarse-grained meat from some other quarter. A great deal of money is spent by people who can ill afford it, because of this notion that the more expensive cuts are the more nutritious; much of it is perhaps attributable to lack of knowledge of the art of cookery. The housewife, not knowing how to properly prepare the cheaper grades of meat so as to make them palatable and attractive, concludes that they are not as nutritious as the more tender and juicy cuts that can be bought only at a higher price, and which require little judgment or skill to prepare for the table. Here is a field for missionary labor that will well repay the cultivation. Knowledge of this kind may be advantageously acquired by those whose means render it perhaps less vital; for a waste of food material is a crime against both pocket and morals." In speaking of the value of meat as a food in relation to the other food stuffs. Prof. Chittenden says: "Various extractives, active principles, etc., all endowed with more or less physiological properties, are likewise ingested as a part of the meat, and add their effects, perhaps to aid in keeping up the tone and vitality of the organism. Meats have certain stimulating properties, which distinguish them from the grosser vegetable foods. In this respect they might perhaps almost be classed with such articles as tea, coffee, etc., in their power of ministering to the wants of the brain and nerves. As Sir William Roberts well says: 'The struggle for existence, or rather for a higher and better existence, among civilized men is almost exclusively a brain struggle, and these brain foods must be regarded as a very important part of the equipment for that struggle. If we compare as best we may with our limited information the general characteristics of the high-fed and low-fed classes and races, there is, I think, to be perceived a broad distinction between them. In regard to bodily strength and longevity the difference is inconsiderable, but in regard to mental qualities the distinction is marked. The high-fed classes and races display, on the whole, a richer vitality, more momentum and individuality of character, and a greater brain power than their low-fed brethren; and they constitute the soil or breeding ground out of which eminent men chiefly arise.' It is well understood that differences in mental capacity may be explained, in part at least, by differences in the type of nutrition of the brain cells, and nutrition is unquestionably modified and influenced by the quality of the food consumed. To again quote Sir William Roberts: 'Trainers will tell you that the hunter and the draught horse require to be fed differently. In the hunter is wanted rapid liberation of energy within a comparatively short space of time; in the draught horse is wanted a more gradual liberation of energy and for a longer period. The hunter is fed on a concentrated and stimulating food, the heaviest and most expensive oats, which, if I may so express it, is the beef of the vegetable feeders, while the draught horse is fed on a lower and less stimulating diet—on Indian corn and chopped hay, food which tends to increase bulk and weight.' So with mankind, the nature and quality of the nutrient—aside from its containing the due proportion of the several requisite elements—exert a specific influence upon the character of mind and body; and meats may be fairly placed in the front rank of foods as giving important aid toward that higher physical and mental development which belongs to the civilization of the nineteenth century."


Uranium.—Until the introduction of the electric furnace by M. H. Moissan, the oxides of many of the metals had been looked upon as irreducible by carbon. M. Moissan, three years ago, isolated the metal uranium in this way. The metal, when pure, is perfectly white, and is not magnetic. It has the remarkable property of emitting invisible phosphorescent rays capable of producing photographic effects through a medium opaque to ordinary light vibrations. The effects are precisely similar to those previously obtained from uranium salts, except that they are nearly four times as intense. The chemical behavior of uranium depends to a certain extent upon its state of division. The metal obtained by electrolysis, which is finely divided, takes fire in fluorine, is attacked by chlorine at 180°, by bromine at 210°, and by iodine at 260°, the reaction in all cases being complete. The powdered metal is completely burned in pure oxygen at 170°, and decomposes water slowly at the ordinary temperature, but more quickly at 100°. Uranium is one of the rapidly increasing group of metals which combine directly with nitrogen at high temperatures, and hence in its preparation it is necessary to work in such a manner as to completely exclude the air.


Working in Compressed Air.—E. W. Moir, in a paper read before a recent meeting of the Society of Arts, gave some interesting data regarding the effects upon the human system of working in compressed air and the various practical means of lessening the danger and overcoming any sudden collapses. Mr. Moir had charge of the work on the Hudson River Tunnel for a time, and has had some connection with most of the underground tunneling ventures of the past two decades. He says: "When I first came to New York the men had been dying at the rate of one man per month out of forty-five or fifty men employed, a death-rate of about twenty-five per cent per annum. With a view to improving this state of things, an air compartment like a boiler was made, in which the men could be treated homœopathically, or reimmersed in compressed air. It was erected near the top of the shaft, and when a man was overcome or paralyzed, as I have seen them often, completely unconscious and unable to use their limbs, they were carried into the compartment, and the air pressure raised to about one half or two thirds of that in which they had been working, with immediate improvement. The pressure was then lowered at the very slow rate of one pound per minute, or even less, the time allowed for equalization being from twenty-five to thirty minutes, and, even in severe cases, the men went away quite cured. No man ever suffers by going into compressed air, unless his Eustachian tubes are blocked, in which case intense pain is produced, owing to the great difference in pressure between the two sides of the ear drum. The above-described lock should be used immediately on prostrations occurring, as it seems to be of little value after some time has elapsed. A very slight increase of carbonic oxide (if it much exceeds one part in a thousand) in the compressed air chamber leads to increased sickness. The impurity never affects a man while below, but only after he comes out, and we had mules working under pressure in New York for over twelve months at a stretch, which sold at good figures after coming out. Every man should be medically examined, and hot coffee should be given to each man before he comes out of compressed air. A warm room to dress in and extra clothing for passage through the lock should be supplied. At the Blackwall Tunnel, with the experience gained and attention to the above points, we have not had a single death, notwithstanding the fact that we had men working under a pressure of thirty-seven pounds per square inch for some time. Generally sparely built men, not too full-blooded, are those who stand air pressure best. A man with weak lungs may work and improve, but one with a weak heart or any apoplectic tendency should not go in at all. Drink of all classes is bad, but such drinks as tend to thicken the blood are worse than spirits."


The Electro-metallurgy of Aluminium.—Dr. Joseph W. Richards recently delivered before the Franklin Institute a very interesting and instructive lecture on the electro-metallurgy of aluminium. Several years ago the daily press gave considerable space to descriptions of the new aluminium industry and discussions of the modifications which its cheap production would bring about in the arts. While it subsequently proved unsuited to many purposes for which it was at first thought well fitted, it has become quite an important staple, and its applications are gradually increasing. Dr. Richards thus describes the process of manufacture: Pure alumina made from ore by a chemical process is stirred into a fused solvent bath composed of the double fluorides of aluminium and sodium. This bath may be simply cryolite, but preferably cryolite to which has been added a further proportion of aluminium fluoride and a little calcium fluoride (fluorspar). The alumina is dissolved by the bath to the extent of one fifth of its weight. The electric current is then sent through this mixture, using for anodes carbon rods dipping into the bath from above. The cathode is formed by the carbon lining of the vessel, on the bottom of which the melted aluminium collects. When the dissolved aluminium has nearly all been removed, the resistance of the bath rises, and fluorine fumes, from the decomposition of the solvent, begin to appear; fresh alumina is then stirred in and the operation thus proceeds continuously. The cavity containing the fused salt has a sump in which the molten aluminium collects and from which it is removed by ladles. The action of the current, when not of too high a voltage, is to decompose only the alumina as long as it is present in the bath in sufficient amount. The oxygen simply combines with the carbon anodes and passes away as carbonic oxide. The above process was discovered independently in 1886 by Heroult in Europe and Hall in America. In 1888 Hall put aluminium thus made on the market. The plants now engaged in making aluminium on this principle are as follows: The Pittsburg Reduction Company, at New Kensington, Pa., and at Niagara Falls, having a daily capacity of 4,400 pounds; the works at the Rhine Falls in Switzerland, capacity 5,000 pounds; and works at La Praz and Saint-Michel in France, with a combined capacity of 5,500 pounds. Besides these, there are in contemplation or course of erection five other plants, which will raise the total possible daily output to 42,900 pounds.


A Convention of Dragon Flies.—Some curious movements of dragon flies were observed one September afternoon by Prof. Charles Barrois, of Lille, along a road near Morbihan, France. The insects were seen, thousands in number, seated along the telegraph wire, all in the same position, their bodies in the axis of the wire, their heads turned west toward the setting sun, and their abdomens making an angle of twenty-five degrees with the wire. New insects were coming from every side, plunging first toward one of those which were fixed, and hovering a few inches away from them, but only for a few minutes. The fixed insect turned its abdomen a few degrees, when the second immediately settled on the wire in the same attitude as the others, into an absolutely motionless position. The distance between the insects varied from about four to twelve inches, the average being about eight inches, while no two were closer together than four inches. They never came with full force upon the wire, but were seen pouncing from all points upon the settled individuals, when the proceedings described above followed; the insect always fixing itself so as to have a little clear space toward the west. Once settled, the dragon flies remained motionless, as if hypnotized by the reflection of the sun from the wire in front of them. Occasionally one would leave the wire, but always to settle itself at once a few yards farther on; none went away upon a long flight. M. Barrels found the wires thus occupied by dragon flies—he estimates that there were sixty thousand of them—for eight or nine miles, to where the line turned abruptly toward the south. The position of the insects, with their heads turned west, indicates that they were attracted by the sunlight; and the space which they all kept to the west of them was that required to afford a clear opening in which the reflection could take place.


Characteristics of Alpine Plants.—As described in Garden and Forest by M. H. Correvon, of the Alpine Garden, Geneva, the vegetation which thrives on great altitudes, like those of the Alps, Andes, Himalayas, and the mountains of Oceania, shows a distinct individual character readily noticeable. The plants are usually stunted, short-stemmed, or stemless, with flowers relatively exaggerated in size. The large flowers are almost sessile, with hardly apparent and only slightly developed foliage, which at a very high level is often clothed with a fine, close down, so as better to withstand the effects of cold nights. In many cases the foliage is glabrous, when it is also usually coriaceous (with tissues especially adapted to resist the frosts of Alpine climates); and the leaf, of a firm, close, thick texture, is provided with a solid epidermis and covered with a waxy coating, which enables it to withstand the effects of the sun as well as those of an excess of humidity. Species that grow in the shade and in well-protected spots are, however, not thus armed. Their foliage is soft and delicate, whereas woolly plants—take the Edelweiss and species having smooth, generally thick and glossy leaves—are usually encountered on arid, unsheltered slopes. Flora of altitudes exposed to the heat of the sun generally produces large, brilliantly colored flowers; while that of shaded situations exhibits very small, pale blossoms, entirely out of proportion to the size of the plant. The influence of the sun and its effect on vegetation are more striking here than elsewhere. Annual species, so abundant on lower levels, are rarely met with in Alpine zones. The short summer there does not permit them to accomplish the complete cycle of their existence in a single season. Alpine plants are always branched from the base with perennial root-stock and stems spreading on the ground, whereby the plant secures protection against inclement nights and severe days. All the activity and energy of the plant is brought to bear on the development of the flower and the reproductive organs. Owing to the conditions under which they thrive, Alpine plants require sometimes several years to accomplish the cycle of their existence, and need more than a single season to produce flowers and seeds. The flora of polar countries has a very different aspect from that of the mountains, though many species are common to both. The polar sunlight, though more constant, is less intense and more diffuse than that of the temperate regions in which most of the mountain flora has its home. The effects of the difference are seen in the plants and flowers.


Holy Wells.—Curious superstitions connected with holy wells are illustrated in M. and L. Quiller-Couch's book about those of Cornwall. Many if not all of these wells date as holy from pre-Christian times, and as it was not practicable or even possible to nullify the people's faith in them, the missionaries had to Christianize them by renaming them and dedicating them to some Christian saints, and there are now few English wells that have heathen names. Heathen rites seem, however, to have lingered round the wells, for it was occasionally necessary in the middle ages to forbid devotions of certain kinds about them. Afterward the reverence for the wells and such practices as bathing crippled children in them and using the water to cure sore eyes, were regarded as papistical. They were supposed to cure illness and madness; if properly interrogated, to reveal the future; and, upon the simple condition of dropping a pin or a piece of money into the water, to secure good fortune to the worshiper. There are still, it is said, wells at the bottom of which pins may be seen. In Portugal, according to Mr. Oswald Crawfurd, the wells are supposed to be haunted by Moorish maidens.


Light-bearing Cephalopods.—An animal of the cuttlefish family, described by Henri Coupin and M. Joubin as Histioteuthis Bonnetliana, of bright rose color, has bright red membranes connecting the tentacles, and on the surface of its body yellow and blue spots of various sizes, with a bright point in the middle. These spots, according to Verany, shine while the animal is alive, but lose their glow after it is dead. They consist of a black cup, wide open at the top, with a large convex lens within the opening forming a kind of cover to it. Another round opening serves as a sort of frame to a second lens. A section lengthwise of the organ discloses a parabolic mirror and the two lenses arranged perpendicularly to each other, the whole forming a sort of black cylindrical lantern closed above by a large lens, which casts a light upward, and in front by another lens throwing it out horizontally. Another cephalopod, colored pale blue or violet, so like the sea as to be hardly visible, found in fine weather on the surface of the Mediterranean—the Chiroteuthis, a poor swimmer—is provided with special organs in the form of nets that are always spread to attract and capture its food of smaller animals. A series of intensely black vesicles may be perceived on its ventral arms, separated by little transparent suckers armed with a circle of sharp teeth. These vesicles are formed externally of concentric lamellæ and internally of a transparent vesicle, the contents of which have strong refracting powers. While the animal is living, light is decomposed by the concentric lamellæ, and the organs are thereby made iridescent with a silvery metallic luster. Smaller animals are attracted by the glitter of these organs, and are then seized by the suckers, which are kept on guard by the side of them. The suckers of the larger tentacles are incapable by their structure of seizing prey, but are helped, as in the case of these vesicles, by a combination of lure and snare, the lure consisting of highly colored vesicles or chromatosperes, and the snare of a network of waving, anastomosed lamellæ which issues from the cup and spreads itself around as a net. The animal swims slowly along, shaking its tentacles around itself, stretching them out and bending them back so as to keep out in the water around it innumerable lines to catch the little animals as they pass and hold them as if in the jaws of a pincers. A third type of hunting organs in this animal is that of special suckers at the ends of the tentacular arms, each containing a black organ forming a lure, with a well-developed sucker at the end.


A Theory of Sheet Lightning.—In his paper on thunderstorms in India, Prof. Michie Smith says that sheet lightning is seen at Madras every evening for six months, always near the horizon and directed toward the southwest. The time of occurrence varies from day to day, but is always toward evening, and generally not later than nine o'clock. The phenomenon is not a reflection of distant lightning flashes, but consists of an actual discharge of electricity from cloud to cloud or between two portions of the same cloud, and it takes place in the upper portions of low-lying clouds. When morning lightning occurs, its direction is northeast, hence the lightning is always to be looked for in the regions of still air where the land and sea breezes meet. The time of occurrence depends on the hour when the sea breeze sets in, the display being about three hours later than this. Cumulus clouds rise together in pairs and the discharge takes place between them, sometimes possibly within them. The author thinks the electrical conditions of the clouds may be accounted for by the fact that the sea breeze is moist and dusty, while the land breeze is dry and dusty. The presence of dust in the clouds is shown when they sink rapidly; the dust is then seen at their edges and gives the iridescent or nacreous appearance frequently observed.


Horticulture an Object Lesson in Evolution.—The study of horticulture and agriculture is held up in Garden and Forest as having a distinct value as a factor in furnishing exercise for certain powers of the mind, and as providing in the systematic examination of the principles of those branches training than which no science affords better. Prof. Bailey, in Science, mentions some of the uses and applications of horticulture in discussing the theory of evolution. It shows the development of life in actual operation. More than six thousand species of plants are cultivated, and most of these have been broken up into varied forms by the hand of man. Some species have produced thousands of distinct forms, and the methods of production of many of them are on record. In place of arguments as to the probable influence of climate upon plants, the horticulturist cites definite cases, so that there is no conjecture about the matter. Instead of speculating upon the transmission of acquired characters, the horticulturist furnishes proof of such transmission. Paleontology brings disjointed evidence in regard to the influence of selection and probable changes from environment, while the horticulturist brings examples before our eyes to prove that he can modify and mold vegetation at his will. The horticulturist creates new species, and shows you numbers of cultivated plants of which no one knows the original form, because the ones with which we are acquainted are so unlike the type that the two can never be connected. This is only a single line of inquiry, and other illustrations quite as striking can be given to show that there is an abundant field for scientific research and profound thought in horticultural science as such.


Physical Characteristics of Cuba.—"In Cuba," says Mr. J. W. Spencer, in his paper on the Geographical Evolution of Cuba, "are mountains higher than any on the eastern side of North America; extensive plains as level as those of the Atlantic coast; valleys formed at the base-level of erosion, and deep cañons carved out by the youngest streams; the remains of enormous beds of limestones mostly swept off the country, and coral reefs and mangrove islands extending the coastal plains into the sea; sea cliffs, caves, and terraces of great and little elevation; drowned valleys deeper than the fiords of Norway indenting the margin of the insular mass; caverns innumerable and rivers flowing underground; rifts through mountain ridges and rock basins; tilted, bent, and overturned strata, dislocated and faulted in modern times, so as to make youthful mountain ranges; metamorphic rocks and rocks igneous, and these again altered to secondary products; old base-level plains or those modified and reaching across the island, having insular ridges of older formations rising out of them, and with the surfaces scarcely incised by the streams; residual soils from the decomposition of the rocks and sea-made loams and gravels; in short, so rapidly are the geologic forces working that one can see a greater variety of structure and learn more of dynamic geology in Cuba than on more than half of the temperate continent." The island is seven hundred and fifty miles long and from twenty-five to one hundred and twenty miles wide. In the western part the ridges of mountains culminate in a point with an altitude of twenty-five hundred feet, but the principal topographic relief is along the southern coast of the eastern extension of the island where Pico Tarquino rises from the Sierra Maestra to an elevation of eighty-four hundred feet. The central portion of the island is generally a plain of from two hundred to four hundred feet above tide, which bears many scattered and interrupted ridges like islands in a sea. Mr. Spencer's study is chiefly confined to this part of the island.


A Word in Favor of Woodpeckers.—The food of woodpeckers has been studied, with a view to determining whether they are injurious or beneficial in the economy of apiculture and forestry, by F. E. L. Beal, who concludes that they do far more good in the destruction of insects than harm with the little fruit and grain they eat and the sap they suck. Of seven species considered, the author regards the downy woodpecker as the most beneficial, it being a great eater of injurious insects, while the vegetable food it consumes is of little value to man. The greatest sin we can lay at its door is the dissemination of poison ivy. The hairy woodpecker probably ranks next in point of usefulness. It eats many beetles and caterpillars, few ants, a trifling amount of grain, and for fruits it seeks the forests and swamps, where it finds wild cherries, grapes, and the berries of dogwood and Virginia creeper. It scatters fewer seeds of the poison ivy and poison sumac than the downy woodpecker. The flicker eats more of ants than of any other kind of insects, and very little corn, while fruit constitutes about one fourth its fare, "but the bird depends on Nature and not on man to furnish the supply." Not one of these three birds shows a questionable trait, and they should be protected and encouraged in every possible way. The redhead woodpecker has a pronounced taste for beetles of very large size. Unfortunately, however, its fondness for predaceous beetles must be reckoned against it. It leads in the consumption of grasshoppers, has a taste, but not a very damaging one, for grain, eats largely of wild fruit, and also partakes rather freely of cultivated varieties, especially of the apple; and in some places feeds extensively on beechnuts. The red-bellied woodpecker is more of a vegetarian than any of the others, but, on the other hand, eats many ants and beetles. The yellow-bellied woodpecker seems to show only one questionable trait, in a fondness for the sap and inner bark of trees. This, comparatively harmless in the forest, may be a serious matter in orchards. The pileated woodpecker is more exclusively a forest bird than any of the others, and its food consists of such elements as the woods afford, particularly the larvas of wood-boring beetles and wild fruits. This species is emphatically a conservator of the forests.