SOCIETY OF PHYSICS AND NATURAL HISTORY, OF GENEVA. 347 



This distiuiiuislied acadomiciaii gave his views as to the manner of un- 

 derstanding- and studying- meteorology, also as to the best form to be 

 adopted for the instruments which are employed in this branch of science. 

 He thinks that meteorology should be considered less as a dependence 

 of astronomy, than as auxiliary to i)hysiology, since it assists especially 

 in determining the isothermal lines, and its principal object is to give 

 account of the physical circumstances which favor or retard the develop- 

 ment of organized beings. As to the instruments, he is in favor of 

 simplifying them in order to render them accessible to the greatest 

 number of people. He proposes particularly to attach to barometers 

 and thermometers photographical registering apparatus moving by 

 clock-work, which will record without trouble the variations of tliese 

 instruments and enable us to read them with perfect exactness. Instru- 

 ments constructed upon this model would be of great assistance in the 

 researches within the domain of physiology, botany, agriculture, etc. 

 The phenomena relative to the aurora borealis have been, as in the 

 past, the obje(;t of different communications from Professor A, de 

 la Hive, who continues to keep the society informed upon this subject. 

 The same member has given an account of tlie imi)ortant researcues 

 whicli he has made in regard to the rotatory magnetic power of liquids. 

 After having devised the apparatus he employed, and the new methods 

 he had adoj)ted to avoid as much as possible all sources of error, he has 

 studied successively different liquids in order to determine their 

 magnetic rotatory i)Ower, such in particular as sulphurous acid, which 

 had not previously been submitted to this kind of experiment, different 

 mitxures of solutions, and a certain number of isomeric bodies of which 

 none i)reseuted the same magneto-rotatory power. The iuiiuence of 

 temperature has also been analyzed with care, and it has been to prove 

 that it tends to diminish this power, which is evidently due to the man- 

 ner in which the particles are grouiied. IM. de la Eive has also presented 

 in concert with M. Edward Sarasin, a work which they have made to- 

 gether on the action of magnetism upon rarefied gases traversed by 

 discharges of electricity. In o[)erating successively u[)on atmospheric air, 

 upon carbonic acid gas, and upon hydrogen, these two physicists have 

 found that the magnetism produces in the ])ortion of gas directly 

 traversed by the discharge an increase of density, and besides an aug- 

 mentation or a diminution of resistance to the couductibility according 

 as the electrical Jet is directed equatorially or axially between the poles 

 of the electro-magnet. These augmentations and dimiiuitions vary with 

 each gas. They are nothing in certain positions of thejet with reference to 

 the magnet, and are probably due, when they manifest themselves, to 

 the perturbation caused by the action of magnetism in the dis])Osition 

 which the gaseous particles aii'ect when they pro])agate electricity. 

 (These two memoirs are inserted in the archives.) M. L. Soret read a 

 memoir upon the polarization of light by water, as studied upon that 

 of dilfci-ent lakes, upon sea- water and upon snow-water. He shows thai 



