404- Mr. Snow Harris on the Electrical Discharge 



all the fossils which occur in the Rhenish slate mountains, 

 such a work could not fail to prove of high interest to every 

 geologist, and its appearance is much to be desired. 



From what is already known of the transition tracts of the 

 Fitchte]ffebiro;e and of Bohemia in the environs of Prague, 

 it may be inferred that the same doctrine of affinities and 

 differences applies there also. It is understood that the late 

 Count Miinster was engaged in a work from which great 

 light might be expected to be thrown on the more ancient 

 formations. As his valuable collections have passed into the 

 possession of the University of Cambridge, we may well an- 

 ticipate that his extensive labours will not be lost to science. 



If the genus Orthis be considered, as it appears generally 

 to be, indicative of the older transition formations, it must 

 also be admitted that the genera Terehratiila, Spirifora, and 

 Leptana are of equal antiquity. 



In fine, even this brief exposition may serve to confirm the 

 opinion which I have formerly expressed, namely, that in 

 widely extended, or distantly separated, lands of transition 

 or protozoic origin, the relations though akin may not be 

 exactly alike ; in other words, that resemblances may exist, 

 but diversities prevail in the details of different tracts, both 

 with respect to the composition and disposition of the mineral 

 masses and the distribution of the remains of organized bodies. 

 Whether the transition formations may ultimately be sepa- 

 rated into definite consecutive groups, is a question which can 

 only be satisfactorily determined by the results of extended 

 comparative inquiries. 



[To be continued.] 



LX. On the Course of the Electrical Discharge, and on the 

 EJjects of Lightning on certain Ships of the British Navi/y 

 .S)-c. 4r. B]/ Mr. Snow Harris, Esq., F.R.S. 



[Continued from p. 128.] 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



24<. TN the instance I last quoted of damage to H.M.S. Rod- 

 ney by lightning, it will be remembered that there 

 was no regular metallic line through which the forces in ac- 

 tion could become neutralized. The electrical agency had 

 therefore to find for itself such a general course, as upon the 

 whole opposed the least resistance to its progress ; and it is 



