Page:Popular Science Monthly Volume 23.djvu/300

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M. Ed. Landrin has deduced from certain experiments that the "setting" properties of hydraulic cements are due to the presence of an allotropic variety of silica which he calls hydraulic silica. He has prepared this form of silica, and has found that it has the property of forming with lime mixtures that harden under water. At the same time, while primarily it is insoluble in hydrochloric acid, it becomes when mixed with lime susceptible to its influence. He has further discovered that aluminates of lime are at least as soluble in water as gypsum, and are liable to spoil any cement in which they may be present.

Herr Josef Knörlein, the entomologist, died at Linz, February 12th, in the seventy-eighth year of his age.

A company has been formed and chartered to construct and work an electric railway running from Charing Cross to Waterloo, in London. The line will pass under the Thames through iron caissons. The power will be transmitted from a stationary engine to the carriages, and these will run separately, starting as filled, and occupying about three and a half minutes in the trip. A contract has been made with the Siemens Company to supply machinery and rolling stock, and the construction of the road has been let, to be finished in eighteen months from the beginning.

The death is announced, at Basle, of Dr. Ziegler, the distinguished cartographer. He studied under Carl Ritter, and afterward established in his native town of Winterthur the cartographic establishment now conducted by Messrs. Wurster and Randegger. His most important maps are his great map of Switzerland, maps of Glarus, of St. Gall, and of the Engadine, and a hypsometric map of the world. A geological atlas and an explanatory description of the geological map of Switzerland by him are now in press.

It is estimated that the ivory which was imported into Great Britain during the nine years from 1872 to 1881 (5,286 tons) represented 296,016 pairs of tusks, and consequently a corresponding number of elephants that have been slaughtered. At this rate of destruction the elephant must in no very long time become extinct. Notice is taken in one of the reports of Mr. Webster, our consul at Shelfield, to the Government of the United States, of the small size of a large proportion of the tusks brought to the market, as indicating a wasteful destruction of young elephants. It is time, if this valuable game is to be preserved, to look for some means of checking the reckless hunting of it which is going on.

Herr Johann Spatzier, a botanist of Silesia, has recently died, at the age of seventy-seven years.

Professor P. C. Zeller, the distinguished Prussian entomologist, died suddenly, of heart-disease, on the 27th of March, in the seventy-sixth year of his age. He was the author of a valuable work on Lepidoptera, and had made important studies of American forms.

More than twelve months ago, a "perpetual" clock was started at Brussels. An up-draught is obtained in a tube or shaft by exposing it to the sun; this draught turns a fan, which winds up the weight of the clock until it reaches the top, when it actuates a brake that stops the fan, but leaves it free to start again when the weight has gone down a little. This clock was keeping good time in June, after running continuously for nine months.

M. Pasteur's recommendation of vaccination as a safe preventive of anthrax in sheep is contradicted by the professors in the veterinary school at Turin, who aver that, in their own experiments, they have found the vaccinated animals to be as liable as any others to be fatally attacked by the disease on inoculation. M. Pasteur has taken notice of their criticisms, and expresses the opinion that the animals they experimented with did not contract and die of anthrax, but of septicæmia, which is infallibly developed twenty-four hours after death in all animals dying of anthrax. He has offered to subject his views to a practical test, by going to Turin and experimenting with the professors, to show that vaccination, while it may not protect against septicæmia, is proof against real anthrax.

Dr. Bertillion, an eminent French statistician, died on the 3d of March last, having reached the age of sixty-one years. He is credited with having made new applications of the study of statistics, and with having been the founder of demographic science. He was also a naturalist and a close observer of animal structure and life; he paid considerable attention to botany; and has left some valuable labors in mycology. Dr. Bertillon's works in science were performed during the greater part of his life without reward. The chair of Demography in the School of Anthropology, offered him in 1876, was the first public position he held. In 1880 he was appointed by the Prefect of the Seine to the head of the Bureau of Municipal Statistics of Paris, which was founded at that time.

M. Tacchini has succeeded in observing the solar prominences upon the very disk of the sun. By enlarging the opening of his spectroscope, he has been able a few times to recognize on the edges of the spots these grand eruptions of hydrogen and the unknown substance helium.