# Popular Science Monthly/Volume 52/February 1898/Fragments of Science

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School Baths and Workmen's Baths in Germany.—From a long paper on the Public Baths of Europe by Dr. E. M. Hartwell, we take the following: The first public school bath in Germany was placed in a common school in Göttingen in 1883, the mayor of that city being prompted to utilize two basement rooms for the purpose through the suggestion of a professor of hygiene that the provision of well-ventilated schoolrooms was likely to be futile if they were occupied by dirty children. The cost of installation was one hundred and eighty-six dollars. The bath proved an eminent success. The example of Göttingen was followed by other cities, until it is now possible to name some forty German, Swiss, and Scandinavian cities that have introduced warm shower baths into their common schools. Certain cities, as Munich, Berlin, Frankfort, and Cologne, have adopted the policy of placing such baths in all new schoolhouses of the class named. The development and spread of the workman's bath have also been rapid and extensive during the past few years in Germany. It seems that bath houses designed to meet the special needs of operatives were in existence in Mülhausen, in Alsace, early in the fifties. Since that time several more similar baths have been built at Mülhausen. In 1873 the firm of Friedrich Krupp erected a central bath house in its well known steel works at Essen. The bathrooms are furnished with tubs, hot and cold water, and shower appliances. Free baths are provided in various parts of the Esssen works for particular classes of workmen, as furnace men. In the Bessemer works, for instance, there is a bathroom which dates from 1893, containing shower appliances. Dr. Hartwell has compiled a list of nearly two hundred ​workmen's baths said to have been established in Germany prior to 1896. In the case of school baths in Germany, the average cost of a warm shower bath is said to be one quarter of a cent, and it is safe to say that, leaving the interest on the plant out of account, the cost in the workmen's baths is about the same, or even less. The cost of the latter baths varies all the way from three hundred and fifty dollars to five thousand dollars—a very good twelve-cabin shower bath, with one hundred and seventy towels and bath caps, having been built at Dalken in the Düsseldorf district for three hundred and forty dollars. Of the great importance of cleanliness in promoting hygienic conditions, it is hardly necessary to speak, and we hope that a similar movement may spring up among the mill owners and large manufacturers in this country. The public schools are also worthy the close attention of our public-school officials.
Explosiveness of Dynamite.—From an article in Industries and Iron, we take the following: In the early days of dynamite the mischievous and often fatal doctrine was thoughtlessly promulgated that under the influence of fire that explosive would only burn, and that nothing would cause it to explode except the application of a proper detonator. Notwithstanding the efforts which have been made to cause the public to unlearn this foolish doctrine, it still lingers. The doctrine preached by those who know anything about the matter is that explosives are only comparatively safe at the best, and then only so long as they are treated as absolutely dangerous. There is no reliance whatever to be placed on the theory that dynamite and many of its congeners can be burned without exploding. This has been illustrated over and over again with fatal results, and the ignorance, crass stupidity, and recklessness occasionally shown by those accustomed to the daily use of high explosives are really incredible. Were the author of a highly flavored story to introduce into his plot the instantaneous death of a newly married couple by an explosion of dynamite in the stove of their sitting room, the explosion being brought about by the bridegroom's brother baking the dynamite in the oven, the author would probably be accused of going beyond the bounds of probability after the sensational, and yet this combination of circumstances did actually occur in a mining district in England. The ingenuity exercised in devising means for thawing dynamite in the most unsafe way possible is certainly very remarkable. This thawing-out process is the most fruitful cause of accidents with dynamite. The dynamite becomes inert at about 40° F., and, while this is a very valuable property for transportation purposes, it plainly also has its disadvantages. To thaw these cartridges tin warming pans constructed on the principle of the glue pot should be provided. This keeps the explosive away from any possible contact with the fire, and prevents the possibility of an excessively high temperature.
Radiography in Medical Practice.—Dr. Francis H. Williams, in an address before the Association of American Physicians, gives an interesting account of his year's work with the X rays, and shows that they must now be accepted as one of the valuable instruments in the general physician's equipment. The varying resistance which the different tissues of the body offer to the passage of the X rays depends upon difference in bulk and chemical composition. The soft tissues of the body contain a large percentage of water, so that they offer about the same resistance as an equal thickness of the latter. The rays, however, pass through air much more readily than they do through water. It is this fact which gives the X ray its special value in physical examinations of the chest. The radiograph of the normal chest shows two clearly marked out lungs, divided by a dark line representing the sternum, and crossed by dark horizontal bands, the ribs. The lower internal portion of the left lung is partially obliterated by the heart, as is also a small segment of the lower portion of the right lung. This picture is normally very sharp and unmistakable, so that any abnormal state of affairs in the lungs and any variation in the size or position of the heart are readily made out by the use of the fluoroscope. In his summary Dr. Williams claims that the X rays, and more especially the fluoroscope, have already proved to be an important addition to the ordinary methods of physical examination, and that ​its use is attended with no harmful results to the patient. The complete address, with some interesting illustrations, appeared in the American Journal of the Medical Sciences for December, 1897.
Artesian Wells in Iowa.—The artesian field of Iowa is described by Mr. W. H. Norton as being only a part of an extensive basin which may be termed the artesian area of the upper Mississippi Valley. It includes a part of Missouri, a large part of Illinois, southern Wisconsin, and southern Minnesota. The intake of the whole field lies in the two States last mentioned. The size of the intake area is roughly estimated at about fourteen thousand five hundred square miles. With the whole Iowa field, it lies within a region of abundant rains, enjoying a mean annual rainfall of not less than thirty-two or thirty-three inches. On the basis of De Rance's estimate that one inch of rainfall per year is equivalent to 14,555,280 imperial gallons to the square mile, or a daily average of 40,000 gallons to the mile, the total annual rainfall of the collecting area of the Iowa artesian field may be estimated at about 475,000,000 gallons to the square mile, a daily average of 1,280,000 gallons or a total annual precipitation for the entire collecting area of 6,887,500,000,000 gallons. Only what of this water does not go into the streams and escape by evaporation is available for the artesian reservoir, but there is every reason for believing that that which falls over the collecting area is more than sufficient to meet all the demands made upon it by the Iowa wells.
Submarine Land Slides and Telegraphic Cables.—While the general result of denudation on the land is to bring material to a lower level, and, by gradually wearing away excrescences like mountain heights, to render such forms more stable, beneath the sea, as Prof. John Milne pointed out at the British Association, such materials are accumulated in slopes, which become unstable as the deposits grow, and facial slidings take place from time to time. The movements are caused by gravity, by subterranean springs, and by submarine earthquakes, the effects of which are at least equal to those we see produced on land, and probably greater. These slidings, occurring along the edges of submarine banks and of the submerged continental frontier, are very damaging to telegraphic cables, which are apparently buried under large bodies of material. Sometimes two or three cables, ten or fifteen miles apart, have been destroyed by such slides. Earthquakes have been felt on land at the same moment that a cable has been broken, and the ocean has been thrown into a state of agitation for one or two days. Under very great disturbances of this kind the resultant earth movement might be recorded, with suitable instruments, at any point on the surface of the globe. In the most remarkable disturbances recorded, changes of depth up to two hundred fathoms have taken place over considerable areas. The study of these dislocations should be established on all the continents and oceanic islands.
School Sessions and Health.—In order to obtain a consensus of opinion on the subject, eight questions bearing upon the influence of our school system on the health and development of the child were addressed by Dr. E. Stuver, of Rawlins, Wyoming, to about one hundred and fifty educators and physicians of the country. Twenty-nine out of sixty-three educators and thirty out of thirty-five physicians did not think our present comprehensive course of study best calculated to develop the highest physical and intellectual powers of the child, and some of the respondents condemned these courses severely. Eighteen educators and one physician were doubtful. Respecting the proper length of continuous school sessions, the average of one hundred opinions were in favor of not longer than one hour or an hour and a half. While considerable divergence appeared concerning the limit of length of a single recitation, the majority of respondents advocated from ten to twenty minutes in the primary and from twenty to thirty minutes in the grammar grades; but much was thought to depend upon the nature of the subject of the lesson, the method of instruction, and the kind of teacher. Frequent recesses met much favor, and many respondents advised one every hour. Of one hundred and five opinions expressed as to the relative merits of open-air recesses with spontaneous play and of formal indoor exercises, all except ​four were strongly in favor of outdoor exercise, or a combination of calisthenics and the old-fashioned recess. While wide divergence of opinion marked the answers of fifty-three educators and thirty-four physicians concerning the effect of home study, all insisted that the work should be carefully guarded and not carried to extremes, and that the health should be properly looked after at the same time. Some thought it did no more harm than attending parties and keeping late hours socially.
Cereal Foods.—In a recent bulletin of the agricultural experiment station at the University of Wyoming there is an interesting examination into the composition of prepared cereal foods, whose results are summed up as follows: "Leaving aside the customary claims of each food to be the best in the market, and considering only the more specific statements of composition, food value, etc., it may be said that these are in many instances entirely unreliable and misleading as to the real character of the food. . . . If purchasers of goods in packages and cans would always note the brand, and afterward buy according to the quality, it would be an encouragement to honest manufacturers, and the grade of such foods would no doubt be raised. There is more variation in price than in composition, and there is no discoverable relation between quality and price. Some articles are four or five times the cost of others of the same class, and apparently of the same merit. . . . The oatmeal sold in bulk is practically the same in composition and, so far as can be judged by personal taste, in quality and flavor as that sold in packages for several times the price. . . . The claims made for quick cooking are generally fallacious. Almost all such preparations should be cooked for at least half an hour, and usually longer, to insure the complete digestibility of the starch."
Value of Disinterested Science.—The address of President F. M. Webster before the sixth annual meeting of the Association of Economical Entomologists, on The Past and Future of Applied Entomology in America, contains an earnest argument in favor of independent investigation as against work in official bureaus and an emphatic denunciation of attempts to harness science to utility as "the worst of all the ill-matched and mismated combinations possible." The author regrets that the mass of mankind can not seem to comprehend that the naturalist, in order to secure results of value, "must work out his problems in a natural way and not as a part of a machine, and that this condition is universal and one which no power on earth can change." In illustration of the value of international work in entomology, the author refers to the monetary value of the benefits this country has derived from the work of two entomologists who were sent several years ago to Australia, one of whom at least "has been able to serve his country and State better since his return," and adds that an American expert is now the official entomologist of Cape Colony, South Africa, and another is in the Argentine Republic, engaged in the investigation of some injurious insects in that country. The author sees that public opinion regarding the entomologists and their work has been changing for the better; but if this change is to continue they must do better work, the results of which will be far reaching and permanent. "The 'powers that be' over and among us must be brought to understand that science is truth and not something that is to be trifled with and debauched, or made to answer for cheap advertisements, or used for the purpose of paying political indebtedness."
Flora of the Sandwich Islands.—Isolated from a continental area, and almost equally so from the other islands of the Polynesian system, says Mr. A. A. Heller, in Minnesota Botanical Studies, Hawaiian vegetation has developed independent of extraneous modifying conditions. That it has done so in a satisfactory way is evinced in the enumeration in Hillebrand's Flora of 999 species of phanerogams and vascular cryptogams, of which 139 are introduced and 653 are endemic, leaving 297 species found elsewhere. Of the 653 endemic species, 250 belong to 40 endemic genera; and these are found principally among the Rubiaceæ, Compositæ, Lobeliaceæ, and Labiatæ. Besides these larger genera, there are smaller ones which have representation only on the northern islands. The great number of ferns appeal to the eye of the botanist. Omitting ​the lower cryptogams, they comprise one sixth of the native vegetation. The comparative scarcity of grasses and of composite and leguminous plants, as contrasted with the unusually large number of Rulaceæ, Rubiaceæ, Lobeliaceæ, and Labiaæ, is a matter of astonishment to the collector from more temperate regions. To the student of the lower cryptogams an immense field is open. Near the summits of the mountains, and in other places where there is a large amount of moisture, the trees, bushes, and ground are draped and carpeted with mosses and liverworts. Lichens seem to be most abundant on the trees and rocks of the lower and middle regions. The "kukui" tree, which flourishes only in the lower forest region, is the host of more species of lichen than perhaps any other tree. Next comes the "koa" tree, which harbors many interesting species, but, as a rule, different from those which are found on the kukui tree. Parasitic fungi are common on the leaves and stalks of many plants, but fleshy fungi seem to be scarce. Marine algae are abundant.
Trades Unions in China.—The following facts regarding trades unions in China are taken from an abstract of Consul Charles's report in the Journal of the Society of Arts. Although labor is cheap in China, the workmen seem able to dictate their own terms. Neither masons nor carpenters begin work in winter much before 9 a. m.; in summer they knock off at noon for a long two hours' siesta, and at all seasons of the year smoke and drink tea, and rest whenever it suits them. According to the regulations of the builders' union, wages, if the men find their own food, are one hundred and eighty cash (about twelve cents) a day. These, in the case of skilled laborers, include their apprentices' wages, which are paid at the same rate. As accidents are frequent in the trade, especially among unskilled hands, the parent of the apprentice has to give an engagement in writing holding the boy's master free from all liability, but a present is expected in case of an accident. No interference is permitted with a customer's engaging any builder preferred by him. No outside firm is allowed to work, however, until it has joined the union and received a certificate, the fee for which varies. Masters have to pay the union at the rate of about one tenth of a cent per diem for every man employed by them, to form a fund to meet subscriptions. A similar tax is levied on assistants to meet the cost of festivals, illuminations, etc. If trouble occurs between a builder and his employees and work is stopped, no other labor can be engaged in until all outstanding accounts are settled. Attendance is obligatory at meetings called to fix the quota to be paid toward subscription funds. There are but five important guilds or trade unions in China—the silk and piece goods, the banks, the sugar, the rice, and the general dealers. The members of these guilds are taxed in proportion to their business to meet the various subscriptions required from the guilds toward canal works, etc. The. funds are also used for the relief of widows and orphans of former members. The whole power of trade in China rests in combination and monopoly.
Rhodesia.—Mr. F. C. Selous, who has spent twenty-five years in the country north and south of the Zambesi—in Matabeleland and Zululand—gave the British Association a favorable account of the climate of Rhodesia, and the adaptability of the highland country to white settlement. He regarded the climate as singularly favorable for the development of Europeans. He had never seen a finer race of men than the Boers and the British colonists of English, Irish, and Scotch descent, who were established in Cape Colony in 1820. They are tall, fine men, and the speaker believed that the highlands of Rhodesia would produce an equally fine race. The country includes the valleys of the Zambesi and Limpopo, where as in all African lowlands, deadly malaria prevails; and it is only the tracts four thousand feet and more above the sea level—in the elevated backbone of the country, which forms the watershed between the Zambesi and the Limpopo in the west, and the Zambesi and the Sabi in the east—that can be looked upon as likely to become peopled by white men. Possibly, as settlement advances, cultivation may gradually encroach upon the lower regions and drive the malaria from them. The superficial area of that part of Rhodesia which lies at and above an ​elevation of four thousand feet extends approximately over an area of twenty-six thousand five hundred square miles, while another seventy two thousand five hundred square miles may be added which lie between three thousand and four thousand feet. The country has suffered much of recent years, with all South Africa, from rinderpest, locusts, and drought, but more favorable conditions are hoped for, and with them anything can be grown that can be grown in Cape Colony. Wheat and oats, however, will have to be raised in the dry season with irrigation. For markets the farmer must look to the local towns, and their growth will depend upon the development of the gold prospects; and a wider market awaits the stock farmer. Matabeleland has been demonstrated to be a good cattle country. The natives formerly possessed considerable herds of sheep and goats, but these were killed and eaten during the scarcity of food. Sheep, however, seem to thrive well, as do pigs and donkeys. Well-bred fowls are subject to much disease, and the native birds are very small and lay small eggs. Horses do badly in all parts of Rhodesia. The speaker did not look upon the land as a ready-made paradise. Such a spot is hardly to be found in the unoccupied world; but "the earthly paradise of a happy home in a wild land must be created by a man's own labor, patience, intelligence, and perseverance."
Liquefied Fluorine.—The much-sought for alkahest, or universal solvent of the ancient alchemists, is almost realized in fluorine, which was first prepared by Moissan in 1886. The transparent vessels in which it is contained have to be made of some fluoride, its action on ordinary glass being vigorous and destructive. The difficulty of handling the gas, even in the laboratory, has hence been very great, the fluoride vessels being brittle and clumsy as well as expensive. Professors Dewar and Moissan, being desirous of more fully investigating the properties of the gas, recently conducted a series of experiments at the Royal Institution, in which by means of liquid oxygen they succeeded in liquefying fluorine, and in this comparatively inert state could more fully and carefully examine its properties. The apparatus used for liquefying the gas consisted of a small cylinder of thin glass, into the upper part of which was fused a platinum tube surrounding a smaller tube of the same material. The fluorine enters through the larger tube, passes around the glass envelope, and escapes through the smaller tube. The glass cylinder being cooled down to the temperature of boiling liquid oxygen (-183°), the current of fluorine gas was passed through the bulb without becoming liquid; at this low temperature, however, the fluorine did not attack the glass. On still further lowering the temperature of the liquid oxygen, by exhaustion, a yellow liquid was seen collecting in the glass envelope, while gas no longer escaped from the apparatus. At this moment the escape tube was closed to prevent the entrance of air, and the glass bulb soon became full of a clear yellow liquid possessed of great mobility. Fluorine thus liquefies at about -185°. The chemical activity of the gas was found greatly reduced when in the liquid state, but even then benzene or oil of turpentine underwent spontaneous decomposition when brought into contact with it. It would thus seem that the powerful affinity of fluorine for hydrogen is the last to disappear. In a subsequent experiment, in which liquid air was used and a temperature approximating -210° obtained, the liquid fluorine showed no signs of solidification. Experiments to determine its density led to the conclusion that it had about the same specific gravity as amber, 1·14. Different samples of the liquid examined with the spectroscope showed no specific absorption bands in the visible spectrum. It was found to be not magnetic.
Monazite.—Much has been said of late years, in discussions concerning the "rare earths" and the search in them for new metals, about monazite; and the mineral has obtained considerable commercial importance in consequence of its use in the manufacture of the incandescent mantles of the Welsbach light. Monazite, as described by H. B. C. Nitze in the Franklin Institute, is essentially a phosphate of the rare earth metals cerium, lanthanum, and didymium. It also usually contains small variable percentages of thoria in the form of thorite or orangite—a derivative of another rare metal, thorium. It ​crystallizes in the monoclinic system, in tubular or short columnar or needle-shaped crystals, usually well developed and free from distortion, varying from microscopic size to five inches in length. It is brittle, transparent in the purest crystals, and of shades of yellow or brown in color. It is an accessory constituent of the granite rocks and their derived gneisses, and has been found in apatite, cyanite, and veined quartz, but not in sedimentary rocks. The economically valuable deposits are found in the placer sands of streams and rivers, in the irregular sedimentary sand deposits of old stream beds and bottoms, now covered up, and in the beach-sand deposits of certain seashores. Workable deposits of monazite have so far been found only in limited geographical areas. The only ones in the United States are the placer beds in North and South Carolina; in Burke, McDowell, Rutherford, Cleveland, and Polk Counties, North Carolina, and in Spartanburg, Greenville, and York Counties, South Carolina. They occur in gravel deposits, from one to two feet thick, in streams that are seldom more than twelve feet wide. Other deposits are found in Brazil, the United States of Colombia, and Russia. The value of monazite depends on its percentage of thoria, the earth sought after by the Welsbach-light men. The Carolina beds furnished one million nine hundred thousand pounds of monazite in 1896, at from six to ten cents a pound. The next year the output fell off, both in amount and price, on account of the competition of the Brazilian field, where the production is easier and cheaper.