Page:Popular Science Monthly Volume 19.djvu/592

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izing the county courts to employ competent persons to fix the north and south lines at the county-seats, at an expense of not more than fifty dollars each.

Recent experiments by Nies and Winkelman indicate that expansion, in passing from the liquid to the solid state, is a more common property of metals than has been believed. Their fundamental experiment consisted in putting the solid metal into the liquid. In some cases the difference in density could be measured. They found that six out of eight metals examined distinctly expanded in solidifying, while the result was obscure in the case of the other two metals. Tin increased in volume 0·7 per cent.; zinc, 0·2 per cent.; bismuth, 3 per cent.; and antimony, iron, and copper in obvious proportions. Lead and cadmium presented difficulties that hindered a satisfactory determination of their qualities.

Kraut has shown that ordinary combustible substances may be set on fire by nitric acid. A wooden box of convenient size was half filled with sawdust, hay, straw, tow, or shavings. A flask containing nitric acid, of at least 1·5 specific gravity, was placed upon this, and the box filled up with the combustible material. The flask was then broken, and a wooden cover was put on the box. Vapors were seen in one or two minutes; a thick, white smoke appeared a little later; and the odor of the burning material was observed. On opening the box a few minutes afterward, the interior was found all on fire, and flames burst out.

M. E. Villari, from experimental measurements of the temperature of the body during acts of motion, has reached the conclusions that the lowest temperature in man, ensuing after a period of rest, is 98·4°; that the temperature increases, under the influence of a positive, ascending effort, to 100·6°, under the influence of a descending effort to 100·3; that it increases after any exertion, but more after an ascending than after a descending one; and that the chemical actions of the organism arc augmented after every movement.

A Sunday Science School at Edinburgh, Scotland, has enrolled ninety-two pupils, and enjoyed an average attendance, from November to July last, of sixty youth who were not able on account of late business hours to attend the evening classes.

M. Pictet recently read a paper before the French Society of Civil Engineers, explaining the operation of his ice-machines, at the close of which he invited the members of the society to visit his works, where two machines are operating with sulphurous acid, one of which produces 2,425 pounds of ice per hour.

The first number of Volume II of "Studies from the Biological Laboratory of John Hopkins University" is just published, and contains among others a lengthy but very interesting article on "The Study of Human Anatomy historically and legally considered."

Mr. Ronald Campbell Gunn, a Tasmanian botanist, died March 14th, aged seventy-three years. He was born at the Cape of Good Hope, and, having removed to Tasmania in 1830, was intrusted with important official positions. He began to investigate the botany and natural history of the island in 1830, and in this occupation rambled over most of the colony. Reports of his work appear in Sir Joseph D. Hooker's "Flora of Tasmania," and in several periodical publications. He was also editor of the "Tasmanian Journal," a scientific publication.

Almost simultaneously with the publication of the discoveries of Messrs. Bell and Tainter in radiophony, M. Mercadier, in Paris, without any knowledge of what they had done, announced that he had been able to reproduce the sounds of speaking and singing upon the photophonic receiver, not only with the light of the sun, but also by means of the electric light, and the oxyhydrogen light.

Mr. John Blackwall, one of the oldest members of the Linnæan Society, died May 11th, aged ninety-two years. His principal work was a monograph on the British spiders, published by the Ray Society, about twenty years ago. He also published "Researches in Zoölogy," in 1834 (second edition, 1873), and a considerable number of papers on general zoölogy.

A market for the sale of toads to gardeners is held regularly every week in Paris. Dealers bring their "goods" in well ventilated casks, in which the toads are packed in lots of a hundred, in damp moss. A lot of a hundred good individuals will bring fifteen to seventeen dollars. The gardeners use them to keep down the destructive insects that annoy them. A Dutch gardener, M. Krelage, of Haarlem, recommends the use of the toad in greenhouses, as furnishing an excellent means for destroying the millepeds that infest the plants.

An International Medical and Sanitary Exhibition is to be held under the auspices of the Parkes Museum of Hygiene at South Kensington from July 16th to August 13th. It will comprise everything that is of service for the prevention, detection, cure, and alleviation of disease.

The French Association for the Advancement of Science will meet at Rochelle next year.