Popular Science Monthly/Volume 24/February 1884/Popular Miscellany
The Ice Age.—At a meeting of the Academy of Natural Sciences of Philadelphia, Professor Heilprin advanced the opinion that the enormous sheet of ice which extended over a large portion of North America and Europe during the Glacial period could not have originated from a polar "icecap." He deemed it doubtful that there could have accumulated in the Arctic regions sufficient snow and ice to propel a glacier probably several thousand feet thick over hundreds of miles, and up slopes to heights of five or six thousand feet. Precipitation in polar regions takes place mainly in a low atmospheric zone; hence it would be impossible for so great a mass of snow to accumulate at so great an elevation as would be necessary to propel southward a glacier of the extent required by geologists. Professor Lewis called attention to a point observed some time ago by Dr. Hayes, but not yet sufficiently appreciated, namely, that the rate of increase in the thickness of the glacier diminished northward. Recent observations of his own showed the glacier to have been 800 feet thick five miles from its southern limit, and 2,030 feet thick at a point eight miles from its edge, while it was only about 3,100 feet in thickness at a distance of 100 miles, and 5,000 feet at 300 miles from its termination. Rejecting several hypotheses, Professor Lewis suggested that the ice-cap flowed south simply because it flowed toward a source of heat. Such a motion not being caused by gravity, would take place in a nearly flat field of ice, and upon his supposition the ice need not have been more than a few times its present thickness in Greenland. Professor Heilprin replied that no laws of glacial action were known which would account for the indiscriminate progression of an ice-sheet toward a source of heat, and that the molecular expansion theory, as applied to the Alpine glaciers, took no cognizance of the direction of the heat-power, but merely of that of least resistance (the trend of the slope). At a subsequent meeting he supported his views previously communicated by statistics of precipitation at different elevations on the Alps, and presented some curious calculations in regard to the rate of progression of the great ice-sheet. Allowing for it the average rate of the Alpine glaciers, one foot a day, it would have required a period of no less than 25,000 years to move from the sixty-fifth parallel of latitude to the line of its terminal moraine. But it may well be questioned if the conditions allowed progression at more than one fifth of this rate. Professor Lewis remarked that arguments, drawn from meteorological conditions as they now exist, will not in all cases apply in considering the Glacial epoch. He further suggested a probable analogy between the Antarctic ice-cap, some 25,000 miles in diameter, and the polar ice-cap of glacial times, and mentioned Croll's estimate that the former is twelve miles thick at its center. In speaking of a polar ice-cap, he did not mean to imply, however, that the ice was necessarily thickest on the pole, but that in Greenland, Labrador, the Hudson Bay region, or elsewhere, there may have been centers from which glaciers grew finally to coalesce into one mass of ice, the top strata of which flowed southward to the great terminal moraine.
Effect of Watering Plants with Acids.—Mr. L. P. Gratacap, of New York city, has published a report of experiments he has made to determine the effect of watering with solutions of acids upon plants. He experimented upon the silver-leaved geranium with hydrochloric, nitric, carbolic, formic, salicylic, sulphuric, tartaric, and citric acids, and water. The plants watered with the first six acids except salicylic were unfavorably affected from the first day of the experiment. From June 22d to September 6th none of the plants died except the carbolic-acid plant, although the nitric-acid plant succumbed shortly after the experiment terminated. Of the rest the sulphuric-acid plant was most thriving, then the hydrochloric-acid plant, and last, and just alive, the plant treated with formic acid. Analyses of the ashes of the plants showed that the acid waters tended to introduce organic ingredients into their tissues. Of hyacinth-bulbs treated in a similar way, only the one treated with tannic acid developed roots. The hydrochloric-acid bulb died, and the sulphuric-acid bulb a month later. After the tannic-acid one, a bulb treated with oxalic acid did best. Tannic acid seemed to increase the intensity of the color of the flower. The plants were dwarfed by the treatment.
Temperature of the Glacial Period.—Mr. G. F. Becker closes a carefully considered review, in the "American Journal of Science," of the phenomena of glaciation with the conclusion that, if the generally received view (the substantiation of which would not be superfluous) that the sun is a gradually cooling body is correct, "it appears nearly certain that the absolute maximum in the development of glaciers is past, and that the glacial period was not one of general cold, but one of higher mean temperature at sea-level than the present." This is advanced without denying that a variety of other causes than those immediately considered by him may have had an influence, and, perhaps, a great influence, upon glaciation. "Indeed, it seems more probable that the formation of glaciers was affected by all contemporaneous changes, such as extraordinary upheavals and subsidences or periodic fluctuations in the eccentricity of the earth's orbit; but, if the reasoning offered is correct, it is not necessary to resort to such events to account for the occurrence of a glacial epoch." He believes that the production of glaciers is chiefly a question of differences between the temperatures at the sea-level and at the level at which the glacier is formed.
Pathology of the Pear.—At a meeting of the New Jersey State Microscopical Society, a paper was read by. the secretary, Dr. Samuel Lockwood, on "Fecal Sclerogen," the last word meaning the indurated particles of lignine in the pear. He showed a quantity of material like sand, which had been passed by a person to whom it had caused great distress. In the microscope it looked unlike any mineral sand, and each particle was composed of a cluster of sharp-pointed crystals, like dog-toothed spar. It even resisted the action of nitric acid, but was dissolved readily by ammoniuret of copper. Suspecting its nature, he took the rind and core of a ripe Bartlett, and gave them to his bees, which were suffering from a dearth of flowers. The insects cleaned away the glucose and all the juices, leaving the pear-grit clean; which, by comparison in the microscope, was identical with the fecal grit. The truth was, the person had been feasting inordinately on ripe Bartletts. The doctor remarked that it had never been cleared up why the pear should cause to many such suffering in the alimentary canal, as its juices were really far less acrid than those of the apple. He showed that it was due to the sclerogen, or pear-grit. Each particle literally bristles with sharp angular points, and the cathartic energy is due to the mechanical action irritating the walls of the alimentary canal.
Growth of Boys and Girls.—The investigations of the Anthropometric Committee of the British Association have made more or less clear several interesting facts respecting the rate of growth of the two sexes in the British Isles. The period of most rapid growth is from birth to five years of age, and then both sexes grow alike, the girls being a little shorter and lighter than the boys. From five to ten the boys grow a little faster than the girls, but from ten to fifteen the girls grow the faster, and at between eleven and a half and fourteen and a half years old are actually taller, and from twelve and a half to fifteen and a half are heavier than the boys. The boys, however, take the lead between fifteen and twenty years, and grow at first rapidly, but afterward slower, and complete their growth at about twenty-three years, while girls grow very slowly after fifteen years of age, and attain their full stature at about the twentieth year. The tracings and tables show a slow but steady increase in stature up to the fiftieth year, and a more rapid increase in weight up to the sixtieth year in men, but the statistics of women are too few after the age of twenty-three to determine the stature and weight of their sex at the more advanced periods of life. The curve of the chest-girth in men shows an increase at a rate similar to that of the weight up to the age of fifty years, but it appears to have no definite relation to the curve of stature. The strength of males increases rapidly from twelve to nineteen years, and at a rate similar to that of the weight; more slowly and regularly up to thirty years, after which it declines at an increasing rate to the age of sixty years. The strength of females increases at a more uniform rate from nine to nineteen years, and more slowly to thirty, after which it falls off in a manner similar to that of males. The curves of strength for the two sexes are not parallel: at eleven years females are weaker than males by twenty-two pounds, at twenty years of age by thirty-six pounds. The fact that man continues to grow in stature up to his fiftieth year contradicts the popular notions on the subject, according to which he ceases to grow before he reaches half that age.
The Extinct Volcanoes of the Pacific Slope.—"According to the "Notes" furnished by Messrs. A. Hague and J. P. Iddings, of the United States Geological Survey, to the "American Journal of Science," the series of extinct volcanoes on our Pacific coast extends northward from Lassen's Peak, near the fortieth parallel, at intervals, for nearly five hundred miles, and follows in general the axial lines of the Sierra and Cascade Ranges. The more prominent peaks of the chain are Lassen's Peak and Mount Shasta, in California; Mount Pitt, Three Sisters, Mount Jefferson, and Mount Hood, in Oregon; and Mounts St. Helen's, Adams, Rainier, and Baker, in Washington Territory. Mount Rainier is the grandest one of the number, and forms the most prominent topographical object in Washington Territory. The surface features of the western part of the Territory have been greatly modified by the lava-flows of the volcano, and four of the important rivers of the region rise among its glaciers. Snow and ice cover its top, reaching downward for five or six thousand feet, while with the most marked contrast the broad base of the mountain supports a dark, dense, grand forest vegetation. The summit is formed by three peaks, the chief of which, a circular cone, with a crater about a quarter of a mile in diameter, rises to 14,444 feet above the sea. Mount Hood is situated directly on the crest of the Cascade Range, about twenty-five miles south of the Columbia River, and is 11,225 feet high. Its summit is a single peak" a portion of a rim of an ancient crater. The crater is about half a mile wide from east to west, and its encircling wall, for three fifths of the circumference, rises 450 feet above the snow and ice that fill the basin. Mount Adams and Mount St. Helen's, on the north side of the Columbia River, form, with Mount Hood, a triangle, the area of which has been the center of great volcanic activity. None of the volcanoes along the belt occupy so comparatively isolated a position as Mount Shasta, which stands upon an open plain with the neighboring hills and ridges many thousand feet lower. Its altitude is given as 14,440 feet, and, as the neighboring ridges rarely attain an altitude of over 3,000 feet, the volcano presents an imposing spectacle surpassed by few mountains in the world. As seen from the west, it presents a double cone, the smaller built upon the flanks of the larger one, and about 2,000 feet lower. Around the broad base of the mountain numerous lesser cones have broken out, one of which, Little Shasta, rises to more than 3,000 feet above the neighboring valley. Seventy miles southeast of Mount Shasta, near the boundary between Nevada and California, is Lassen's Peak, which, though it is about 10,500 feet high, is by no means so conspicuous an object as many of the volcanoes, because it is surrounded by other peaks of considerable elevation. It is a broad, irregularly shaped mountain, with four prominent summits, and bears on its slopes abundant evidence of comparatively recent extrusions of lava.
Science and Jack-Puddings.—"Mr. R. A. Proctor, in "Knowledge," notices the single abusive utterance that was made against Mr. Herbert Spencer while he was in this country, and which came, not from a corner saloon, but from a pulpit, and remarks of it that it is difficult to say whether the terms used by the preacher "are more strikingly contrasted with the teaching and method of the writer he attacks or with those of the intelligent, well-trained, and well-educated clergymen who have, indeed, dissented from some of the inferences which appear to them to follow from modern scientific theories, but who know well that they would but degrade their cause and themselves (to say nothing of their calling) were they to substitute reviling for rhetoric and railing for reasoning." Then Mr. Proctor quotes such passages from the attack as are fit for publication, and adds: "Nearly three centuries ago there was at least earnestness in the arguments used by priests, and monks, and friars, against the fearful doctrine that the earth goes round the sun. Unwise though their conduct, and unjudging their intolerance, they believed what they taught, and in their day their belief was natural enough. It is encouraging to find that in our day the advance of science is only opposed by the untaught and the foolish; only abused by the ranter and the Jack-Pudding. When we consider how necessary are certain doctrines for the world's welfare—even though hereafter they may have to give place to higher and broader and deeper truths—it is well to see that those who do their best to discredit those doctrines are not now men whose words have any weight, are not even fanatics or bigots, but simply—clowns and charlatans."
The Recent Eclipse of the Sun.—The formal reports of the observations of the solar eclipse of the 6th of May last have not yet been published; but a few preliminary statements respecting them have appeared in the journals. The American, French, and English parties arrived safely and in good time at Caroline Island, and set up their apparatus under generally satisfactory conditions. The day of the eclipse opened rather unfavorably, but the sky cleared before the first contact. The clouds continued, however, to float around, so that the corona was partly hidden during twenty seconds of the first minute of totality, and the phenomenon was wholly obscured after the cessation of totality. As totality, however, lasted for nearly five minutes and a half, good observations of that stage were obtained. The supposed intra-Mercurial planets were sought but not found. Photography does not seem to have given the results that were expected from it; but it is said that proofs were got the combination of which will permit the reconstruction of the entire corona as it was shown at the time. Mr. Hastings, of Baltimore, made some observations on the spectra of the opposite sides of the corona, from which he has drawn the conclusion that the outer portions of it are not real, but are effects of diffraction. This conclusion, "Ciel et Terre," of Brussels, observes, would account for the differences of form which the corona exhibits to different observers, but fails to account for the predominance of coronal light toward the solar equator. M. Janssen observed anew that, besides the spectrum of bright lines, the corona gives a weak continuous spectrum showing some of the principal dark rays of the solar spectrum. This would favor the theory that the light really proceeds from the coronal appendage, and that its exterior is made up of a mass of meteors reflecting the light of the sun—a theory that is already supported by the results of polariscopic analysis. It is also stated that M. Tacchini has observed near the limit of the coronal atmosphere the spectrum of a hydrocarbon similar to that which comets give when they are far from the sun.
Function and Structure.—The French Academy of Medicine recently discussed the question whether an identity of action exists between the living tissues of animals and of men. M. Bechamp denied any similarity, and alleged differences in the properties of the salivas of man and animals, and between the milks of man, the cow, and the goat, in support of his view. The answer to this, as suggested by the "Lancet," is that, in the process of evolution, function precedes structure; hence the legitimate corollary is deduced that the properties of a tissue are more delicate tests of its nature than the structure. It is more than probable, however, that in drawing this conclusion we are swerved by the imperfections of our senses, and that molecular structure goes hand-in-hand with function, and that a change in property is accompanied by a corresponding variation in the arrangement of the constituent atoms of a molecule. Every cell and every molecule has its individual characteristics, and these idiosyncrasies may extend to different individuals of the same species, to different species, and to different genera.
A Home-made Microphone.—Some of the readers of this journal may be pleased to have a description of a little microphone that has given good results, and which can be made, in a few minutes, from material at hand. It is represented in the figure of the natural size. It is made from a visiting-card of the ordinary thickness cut square. A round card might look better, but it will give less satisfaction. On the card should be fastened with sealing-wax three thin, light disks of carbon, BBB', of the quality used in the electric light.
The disks should be placed symmetrically at the angles of an equilateral triangle, and should be put in communication with each other by the copper wires bbb’ which are either soldered or stuck tightly into holes made in each disk to receive them. Platinum may be advantageously substituted for copper. The rest of the apparatus consists of a square wooden foot, M, supporting three prismatic rods of carbon, CCC', arranged so as to correspond exactly with the three disks BBB'. Two of the rods, CC, communicate by the copper or platinum wires dd with the common terminal D, while the third rod, C, communicates alone with a second terminal, D'. The upper ends of the charcoal rods should be cut into a bevel-shape—not into a point, for that does not give sufficient contacts. The rods are sealed to the wooden base M. The theory of this microphone is very simple. The current enters, for example, by the terminal D', follows the rod C, then the disk B', whence by the wire b it passes by the two disks B to return to the terminal D through the two rods CC. The little instrument may be made very sensitive to the voice and to all sounds, provided the card A is given the proper weight, and is neither too heavy nor too light. The voice, with its timbre, of a person speaking in his usual tone at the other side of the room, can be heard very distinctly in it. The sounds of the piano are particularly well reflected. The apparatus should be placed upon a table two or three metres away from the sound. For a battery to put the microphone in action, I have generally used a small Bunsen element. Two or three Leclanché elements would do as well. I have used a modification of the Leclanché elements, in the shape of a pile made of a plate of zinc and a carbon plate, moistened with a saturated solution of bichromate of potash and hydrochlorate or sulphate of ammonia. It is in fact the bichromate pile without the costly mechanism which is used for relieving the zinc from the action of the acid when the apparatus is at rest. This element does not waste when the current is interrupted, as in the Leclanché pile. A difficulty which arises in the use of the pile, from the penetration of the carbons by the ammoniacal solutions till they attack the wires, has been obviated by M. Préaubert's device of exposing the carbons to a bath of boiling paraffine, which destroys their capillarity, while it does not affect their conducting power. The superficial paraffine may be scraped off after the bath. Piles may be obtained by this means that will endure indefinitely, and have, apparently, an electro-motive force superior to that of a Leclanché pile of the same dimensions.—M. A. Bleunard (translated for the Popular Science Monthly from La Nature).
Lightning without Audible Thunder.—A correspondent of "Nature" reports a violent rain and lightning storm which took place near the crest of the Apennines, and during which no sound of thunder was heard. The writer also describes two other such storms that he witnessed on the edge of the Montenegrin highlands. "On these nights," he states, "the lightning was so incessant and vivid that we were able to walk about, choosing our way among the stones and shrubs as readily as by daylight, the intervals between the flashes being, I should judge, never more than a minute, while much of the time they seemed absolutely continuous, the landscape being visible in all details under a diffused violet light. Looking overhead, the movements of the lightning were easily discernible, the locality of the discharges varying from one part of the vault to another in a manner which it was impossible to confound with the reflection of lightning from a distance. Like the storm of last night, those were followed by copious rain, but not a single peal of thunder was heard during the whole night."
Combustion-Products from Different Lights.—The following figures show the amount per hour of combustion-products from several varieties of artificial light. Unless the electric light has some peculiar injurious influence, it has a great superiority on sanitary grounds:
LIGHT OF 100 CANDLES.
in cubic metres.
|Heat, in ca-|
|Electric lamp, arc||0||0||57-158|
|Electric lamp, incandescent||0||0||290-536|
|Lamp, petroleum, flat flame||0∙80||0∙95||7200|