526 



Mr. A. Schuster. 



Observations, &c. (continued). 



Tacubaya : — Observatorio Astronomico Nacional. Anuario. 1890. 



12mo. Mexico 1889. The Observatory. 



Toronto : — Meteorological Office. Report of the Meteorological 

 Service of the Dominion of Canada for the year ending 

 December 31, 1886. 8vo. Ottawa 1889. The Office. 



Washington: — U.S. Coast and Geodetic Snrvey. Bulletin. Nos. 

 14-17. 4to. Washington 1889. The Snrvey. 



The Fur- Seal and other Fisheries of Alaska. Report from the 

 Committee on Merchant Marine of the House of Representa- 

 tives. 8vo, Washington 1889. The U.S. Fish Commission. 

 U.S. Navy Department. Hydrographic Office. Pilot Chart of 

 the North Atlantic Ocean, April, 1890. [Sheet.] Washington. 



The Office. 



Wellington : — Registrar- General's Office. Statistics of the Colony 

 of New Zealand. 1888. Folio. Wellington 1889. 



The Registrar- General. 



Bakerian Lecture.— tc The Discharge of Electricity through 

 Gases. (Preliminary Communication.)" By Arthur 

 Schuster, F.R.S. Received and Read March 20, 1890. 



" If we accept the hypothesis that the elementary substances are composed of 

 atoms, we cannot avoid concluding that electricity also, positive as well as negative, 

 is divided into definite elementary portions, which behave like atoms of electricity." 

 — Helmholtz (Faraday Lecture). 



• I. Introduction. 



The phenomena of the electric discharge in gases excite a wide- 

 spread interest at the present time. It could hardly be otherwise ; 

 for although our knowledge of electric manifestations is increasing 

 in all directions, we cannot be assured of the correctness of our ex- 

 planations while the mysterious appearance of the gas discharge 

 remains unexplained. As long as we still have to account for a 

 series of most puzzling facts, it seems possible that we are on the 

 wrong road altogether, and that there may be some surprise in store 

 for us which will ultimately compel us to reconsider all our present 

 ideas. I have endeavoured during the last ten years to study the 

 gas discharge, with a view to finding some explanation which should 

 be in agreement with the conclusions drawn from other parts of 

 physics. 



In the year 1884 I presented to the Royal Society* an outline of a 



'Roy. Soc. Proc.,' vol. 37, p. 317 (1884). 



