288 



THE POPULAR SCIENCE MONTHLY 



M. Ed. Landrin has deduced from cer- 

 tain experiments that the " setting " prop- 

 erties of hydraulic cements are due to the 

 presence of an allotropic variety of silica 

 which he calls hydraulic silica. He has pre- 

 pared 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 gyp- 

 sum, and are liable to spoil any cement in 

 which they may be present. 



Herr Josef Knorlein, the entomologist, 

 died at Linz, February 12th, in the seventy- 

 eighth year of his age. 



A company has been formed and char- 

 tered to construct and work an electric rail- 

 way running from Charing Cross to Water- 

 loo, in London. The line will pass under the 

 Thames through iron caissons. The power 

 will be transmitted from a stationaiy engine 

 to the carriages, and these will run sep- 

 arately, 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 es- 

 tablished in his native town of Winterthur 

 the cartographic establishment now con- 

 ducted 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) repre- 

 sented 296,016 pairs of tusks, and conse- 

 quently a corresponding number of ele- 

 phants 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 val- 

 uable game is to be preserved, to look for 

 some means of checking the reckless hunt- 

 ing of it which is going on. 



IIerr Johann Spatzier, a botanist of Si- 

 lesia, has recently died, at the age of seventy- 

 seven years. 



Professor P. C. Zeller, the distin- 

 guished Prussian entomologist, died sud- 

 denly, 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 stud- 

 ies of American forms. 



More than twelve months ago, a "per- 

 petual " 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 vac- 

 cination 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 septicaemia, 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 pro- 

 tect against septicaemia, is proof against real 

 anthrax. 



Dr. BErxTiLLON, an eminent French sta- 

 tistician, died on the 3d of March last, hav- 

 ing reached the age of sixty-one years. He 

 is credited with having made new applica- 

 tions of the study of statistics, and with hav- 

 ing been the founder of demographic sci- 

 ence. 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 per- 

 formed 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 Mu- 

 nicipal Statistics of Paris, which was found- 

 ed 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 un- 

 known substance helium. 



