46 Mr. R. Adie on the Electrical Currents induced 



from E.N.E. to W.S.W., and under them towering masses of 

 cumuli, presenting a strange and wild appearance. The auroral 

 light nearly equalled that of the moon when similarly clouded. 



" 1853. Jan. 7, 7 h to 10 h p.m. Sky covered by thin hazy 

 streaks of cirri, much resembling faint auroral clouds, and like 

 these only dimming the stars. They extended across the sky from 

 N.byE.toS.byW., and were occasionally traversed by pulsations, 

 apparently from W., but too rapid to admit of this being satis- 

 factorily determined. Wind gusty from S.W. No aurora was 

 seen except a few slender streamers, which appeared for a few 

 minutes about 9 h p.m. just above the N.N.W. point. 10 h p.m. 

 Cirri as before, but no pulsations now distinguishable. Wind 

 not so gusty as before. No auroral appearance visible. 



"March 12, 10 h p.m. Clear and frosty, faint auroral light in 

 N.N.W. A faint luminous streak extended from Orion's belt 

 by Presepe to the head of Leo. This soon disappeared, and 

 shortly afterwards reappeared in the same position. An arched 

 bank of clouds, apparently cirrostrati, in N.N.W. In a few 

 minutes broad, dark, hazy cirrostratus bands appeared in N.W., 

 then overhead, and soon after over the whole sky, crossing the 

 magnetic meridian at right angles." 



V. On the Electrical Currents induced in the Metallic Cross. 

 By Richard Adie, Liverpool*. 



THE following communication has for its object to show that, 

 in a metallic cross made of one metal, when there is a 

 want of homogeneousness, or other source of resistance to con- 

 duction, at the crossing of the bars in their centres, a galvanic 

 current passed through one pair of the arms induces in the other 

 pair of arms an electrical current, which has no connexion with 

 unequal heating or thermo-electrical effects. The experiments 

 appear to me to give a very pretty illustration of a series of elec- 

 trical currents, corresponding in their intensity to those derived 

 from thermal sources, but produced by a want of homogene- 

 ousness in the conducting materials, and without the aid of 

 unequal heating, which for thermo-electricity is indispensable. 



In the January Number of this Journal, vol. v. p. 46, I gave 

 an explanation of the cross, founded on experiments which I had 

 published some years previously in the Edinburgh Philosophical 

 Journal. As I again wish to return to the subject, I may pre- 

 face my remarks by stating for the information of those who 

 may not be familiar with the matter, that the metallic cross was 

 designed on the Continent several years ago on purpose to show 



* pommunicated by the Author. 



