328 Mr. Armstrong on the electrical Phaiiomena 



_^2±£d\l _2R __^„. ._^ 



x'^ + y'^ dp r"^ d^ p d"^ p 



— 2p-^^ + 2y- . -r+ 'yy-4- + V ^j—^ 

 z'^ «~ ^" ax a:: • a yds 



^ dxdx: ' dydz z ' d z^ 



The form assumed for R makes the four first terms of the 

 last equation destroy each other. Removuig these, and sub- 

 stituting the value of R in the otiier terms in which that letter 

 occurs, we have t/iree differential equations to determine two 

 unknown functions. Unless if can be shown that one of these 

 equations can be deduced from the other two, the discovery 

 of these two uniinown functions must be, in the nature ot 

 things, impossible. Without professing to have examined the 

 equations minutely, I can only say at jjresent that the three 

 equations appear to me to be inconsistent, and therefore I con- 

 sider that the motion assumed by Professor Challis is impos- 

 sible, even when accompanied with any other transversal mo- 

 tions whatever. The ow?« of proving that the three equations 

 are consistent, rests with the supporter of such a solution as 

 that to which I have alluded. 



I am, Gentlemen, 



your very obedient servant, 

 Royal Obseivatoiy, Greenwich, G. B. AlRY. 



March 22,184]. 



LV. On the Electrical Phccnomena attending the Efflux of 

 Condensed Air, and of Steam generated wider Pressure. By 

 Wm. Geo. Armstrong, Esq.'^ 



'T^HE investigation of the causes which induce and modify 

 the development of electricity during the emission of 

 steam and compressed air, derives unusual importance from 

 the prospect it affords of elucidating certain obscure principles 

 in electrical science, and of leading to an explanation of seve- 

 ral meteorological and other natural phtenomena, of which no 

 satisfactory theory has been hitherto adduced. The mere 

 novelty of the subject, and its connexion with that mysterious 

 and all-pervading agent, electricity, the further knowledge of 

 which is so essential to our progress in natural philosophy, 



* Communicatee] by the Author : see p. 265 of our last Number. 



