Popular Science Monthly/Volume 38/March 1891/Notes
The conclusions expressed by Prof. Key, in the November number of the Monthly, respecting periods of growth in school children, seem to be confirmed by the measurements of Dr. Henry P. Bowditch in the schools of Boston. From these measurements, Dr. Bowditch observed in the National Academy of Sciences, it was shown that the big boys and girls get their growth earlier in life than the small boys and girls. The latter make up their relative proportion, but not till about a year later in life. The same fact was proved regarding height and weight. There was also shown to be a period of what the author called "female superiority," when the girls are the superiors in height and weight of the boys of the same age. This age is from about fourteen to sixteen years.
Experiments are being tried in Germany in making horseshoes of a material the chief constituent of which is paper. It is said to fit to the hoof better than the iron shoe, to be impervious to water, and to grow rough under use, so as to become a safeguard against slipping.
M. Armand Viré has discovered some dozen rocks in the valley of the Lunain, France, covered with smooth furrows running in various directions, which the people there believe to be scratchings of the devil's claws. They were used, it is supposed, during the Quaternary epoch, for finishing off the stone hatchets.
A portable boat has been devised by Colonel Apostoloff, of the Russian army, which may be constructed instantly by making a framework with the lances of the Cossacks and covering with a tarred cloth. Two boats are capable of carrying thirty-six men, with their baggage and arms.
MM. Fremy and Verneuil have continued their experiments in the manufacture of artificial rubies, which attracted attention several years ago, and, improving their processes, have made it successful on a considerable scale. They now obtain crystals weighing a third of a carat. In their later processes they add carbonate of potash to crude alumina, with bichromate of potash for color. The process, with the agitation of fluoride of barium, is continued for a week without interruption, at a temperature of 1350° C. Several times in the course of their experiments they have observed the red crystals of the ruby formed along with the violet and blue crystals of the sapphire. Mineralogy as well as jewelry is likely to profit by these operations, which are destined to cast light upon the coloring of gems.
Painted human bones have been found by Prof. Vasselovski in two prehistoric graves in the Crimea. Such bones had previously been found in three other graves. They are supposed to belong to the original inhabitants of the Crimea, the Cimmerians of Herodotus, who laid their dead on elevated spots till the birds consumed the flesh, and painted the skeletons, when they were bleached, with some mineral pigment. Painted skeletons have also been found in central Asia. In some informal remarks at the meeting of the American Folk-lore Society, Dr. J. W. Fewkes gave the results of observations among the Zuñi Indians at Pueblo, which go to show how the traditions of the tribe survive in a kind of dramatic representation by dances. He thought that many historical events could be traced by making a careful study of the dances.
The trustees of the American Museum of Natural History have just opened a collection of the woods of the United States, gathered under the direction of Prof. Sargent, editor of Garden and Forest, and presented by Mr. Morris K. Jesup. It is nearly exhaustive, and represents four hundred and twelve species, including nearly all trees that are large enough to be considered of commercial importance. Attached to each species is a small colored map showing over what areas in the United States the wood is found, while near by are water-color drawings of flowers and fruit of the species, in nearly natural size and colors. In another hall arc cases of specimens in economic entomology, illustrating the work of insects injurious to forest trees.
The latest attempt to solve the "smoke problem" is the scheme of Mr. Elliott, of London, for condensing the smoke in water and recovering the by-products. The smoke is drawn from the chimney by means of a fan into a tank of water in which revolving stirrers arc moving; by these the products of combustion are churned up and arrested and condensed in the water. When the water is fully charged, it is drawn off, and the tank is filled with fresh water. The charged liquor is to be afterward treated, and the byproducts due to the combustion of the coal are to be recovered.
According to a paper of Prof. John Trowbridge, the discharge from a Leyden jar is not a single act, but is a series of oscillatory movements back and forth till an equilibrium is reached. The oscillations take place in 1000000 of a second.
A gigantic pendulum — a bronze wire, a hundred and fifteen metres long, with a steel globe weighing ninety kilogrammes at the end has been suspended in the Eiffel Tower, for the purpose of demonstrating visibly the motion of the earth.
A leprosy commission has been dispatched from England to India, which, after an investigation of one year, is expected to report concerning the desirability or otherwise of encouraging the voluntary partial withdrawal of lepers from among the non-leprous population; of enforcing the complete isolation of all lepers; and of enforcing the isolation of certain lepers. It will also report on the best methods of accomplishing whatever may be decided upon.
The California Museum Association of Sacramento offers a prize of two hundred and fifty dollars for an invention to utilize the rise and fall of the tides, giving not less than three horse-power for six hours; also two hundred and fifty dollars for an inexpensive device to improve the hygienic conditions of the air in rooms. Inventors to retain all rights. Plans should be sent in by April 1, 1891. Full details on the matter can be obtained by addressing J. A. Woodson, president, Sacramento, Cal.
Dr. Charles A. Oliver has described, in the Transactions of the American Ophthalmological Society, a system of tests, and the apparatus required, which he has devised for detecting color-blindness in railway service. The first test consists in matching wools, being a modification of the Holmgren method; the second requires the recognition of squares of bunting in a series of black boxes at one thousand yards distance; and the third is like the second, except that illuminated colored glass is used instead of bunting, and the test is conducted at night. A spectacle-frame is also used in which different glasses can be inserted so as to produce the light effects of various sorts of weather. A number of advantages are claimed for the system.
In a paper in the Society for the Promotion of Agricultural Science, Prof. Manly Miles remarked that the interdependent biological relations of different farm crops and of the soil microbes that find favorable nutritive conditions in the vicinity of their roots appear to be as important factors in farm economy as the chemical constitution of soils and crops, and the conditions of soil that influence these relations are of great practical interest. The applications of science to agriculture will be best promoted by investigations concerning the life histories and relations of these microbes.