404? Mr. Snow Harris on the Electrical Discharge 
all the fossils which occur in the Rhenish slate mountains, 
such a vrork 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 
Fitchtelgebirge 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 Munster 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 Terehratula^ Spirifera^ and 
Leptcena 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 
Effects of Lightning on certain Ships of the British Navp^ 
4’c. ^c. By Mr. Snow Harris, Esq,^ F.R.S, 
[Continued from p. 128.] 
To the Editors of the Philosophical Magazine and Journal, 
Gentlemen, 
24. T N 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 
