Proceedings of the Polytechnic Association. 1011 



Some members wished Mr. Emery to explain what results would 



he due to very higli steam used expansively ; hut the hour of closing 



having arrived, the Chairman requested the speaker to continue the 



subject at the next meeting. 



Adjourned. 



March 31, 1870. 



Professor S. D. Tillman iu the chair; Egbert Weie, Esq., Secretary. 



The Chairman opened the proceedings by reading the following 

 notes on science and its application to the useful arts : 



Observatory on Mount Ararat. 

 The Paris Cosmos says that the Russian government has resolved 

 to establish an astronomical and meteorological observatory on this 

 mountain, situated near Tiflis, in consequence of the excellent report 

 given by Dr. Piazzi Smith of the fitness of such high situations, 

 derived from his experience on the Peak of Teneriffe. 



Platinum Light. , 



M. Schinz states, in the Cosmos, that his experiments prove that 

 platinum brought to a white heat by means of the ignition of a mix- 

 ture of hydrogen and carbonic oxyd gases yields a light whicli, in 

 relation to the illuminating power of that of good coal gas, is as 1.24 

 to one. 



Gases in ArxVble Soil. 



M. Herve Mangon, writing on this subject in the Cosmos, states 

 that, akin to most porous substances, arable soil has the property of 

 condensing gases. He found that the quantity of gases thus con- 

 densed varies in bulk (for the same quantity of soil) from two to ten 

 volumes of gas. 



Colors of Gases in Geissler Tubes Changed by Magnetism. 



M. Treve, in a recent communication to the French Academy of 

 Sciences, gives an account of his experiments with gases inclosed in glass 

 tubes and exposed to a current of electricity, and at the same time to 

 the influence of a powerful electro-magnet. Having taken a Geissler 

 tube filled with hydrogen, one portion of the tube being drawn out 

 to capillary thinness, he caused the induction current to pass through 



