84 Lord Kelvin and Mr. M. Maclean. [May 31 T 



Journals (continued). 



Zeitschrift fur Naturwissenschaften. Bd. LXVX Heft 5 6. 

 8vo. Leipzig 1894. 



Naturwissenschaftlicher Verein, Halle, 



Dollen (W.) Stern-Epbemeriden auf das Jahr 1894. 8vo. Dorpat 



1894. The Author. 



Girouard (D.) Lake St. Louis Old and New Illustrated and Cavelier 



de La Salle. 8vo. Montreal 1893. The Author. 



Hunt (A. R.) On certain Affinities between the Devonian Rocks of 



South Devon and the Metamorphic Schists. 8vo. London 1892 ; 



[and three other pamphlets. 8vo.] The Author. 



Hutchinson (Rev. H. N.) Creatures of other Days. 8vo. London 



1894. The Publishers. 



Marsh (O. C.) Restoration of Elotherium. 8vo. [New Haven~\ 1894. 



The Author. 



May 31, 1894. 







The LORD KELVIN, D.C.L., LL.D., President, followed by Sir 

 JOHN EVANS, K.C.B., D.C.L., LL.D., Vice- President and 

 Treasurer, in the Chair. 



A List of the Presents received was laid on the table, and thanks 

 ordered for them. 



The following Papers were read : 



I. " On the Electrification of Air." By LORD KELVIN, P.R.S. T 

 and MAGNUS MACLEAN, M.A., F.R.S.E. Received May 9, 

 1894. 



1. That air can be electrified either positively or negatively 

 is obvious from the fact that an isolated spherule of pure water y 

 electrified either positively or negatively, can be wholly evaporated 

 in air.* Thirty-four years ago it was pointed out by one of 



* This demonstrated an affirmative answer to the question, Can a molecule of a 

 gas be charged with electricity ? ( J. J. Thomson, ' Kecent Eesearches in Electricity 

 and Magnetism,' 36, p. 53) and shows that the experiments referred to as point- 

 ing to the opposite conclusion are to be explained otherwise. 



Since this was written, we find, in the ' Electrical Review ' of May 18, on page 571, 

 in a lecture by Elihu Thomson, the following : " It is known that as we leave the 

 surface of the earth and rise in the air, there is an increase of positive potential 





