C. GENERAL PHYSICS. 143 



more than forty years ago, and made them the subject of a 

 memoir inserted in The Journal of the FrcmJdin Institute of 

 Philadelphia, January, 1836, and again in The London and 

 Edinburgh Philosophical J/a^asme, March, 1845, in a paper 

 entitled " Is Capillary Attraction an Electrical Phenom- 

 enon ?" In these memoirs Mr. Lippraann's facts are set 

 forth, and the explanation of them is given. Dr. Draper 

 formerly wrote a good deal on capillary attraction, regard- 

 ing it simply as an electric phenomenon. His views on the 

 subject are given in detail in the scientific journals above 

 named, and also in The American Journcd of Medical /Sci- 

 ences, 



ON THE ELASTICITY OF GASES. 



One of the most extensive experimental researches of 

 modern times is that now being prosecuted by Mendelejeif 

 on the elasticity of gases, the expenses of which are being 

 defrayed by the Imperial Russian Society of Technology, 

 the first of which is now published in the Russian language. 

 Experiments made by Oersted, Rumford, Natterer, and Cail- 

 letet lead one to think that under considerable pressures all 

 gases are compressed less than they should be as indicated 

 by Mariotte's law. The greater part of the first volume of 

 Mendelejeff's work is of course occupied with preliminary re- 

 searches necessary to establish the accuracy of his instru- 

 ments and methods. The volume concludes with a descrip- 

 tion of the first experiments made by him upon rarefied gases 

 and upon air compressed under from one to three atmos- 

 pheres. The results that he has obtained in operating upon 

 air, hydrogen, and carbonic acid, under gradually decreasing 

 pressures, lead to the conclusion that the product of the 

 pressure into the volume diminishes with the pressure ; the 

 diminution being especially sensible for air, when the press- 

 ure becomes very feeble. 6 B^ LXXXL, 501. 



THE ELASTICITY OF PUKIFIED AIR. 



Some researches of Mendelejeff'and Kirpitschofi'show that 

 the product of any volume of air by its pressure, which ac- 

 cording to the law of Mariotte should be constant for all 

 pressures, is not so for the air, varying considerably when 

 the pressures diminish to so small a quantity as half a milli- 



