On Galvanic Series formed of Zinc and inactive Iron. 115 
the former the following measurements of the corpuscles were 
taken. Long diameters, l-4000th very common, many l-3555th, 
and a few, not commonly seen, 1 -2666th. Several considerably 
shorter than l-4000th of an inch, for instance, l-5333rd; and 
even l-6000th very rarely. Short diameters most frequently 
l-6400th and 1-71 i 0th. The shorter corpuscles are generally 
broader in proportion than the others, some nearly circular, 
but in this observation none perfectly so. Mr. SiddalFs 
measurements agree as nearly as possible with mine, and 
the corpuscles in the Vicugna appear to be a little smaller 
than those of the Dromedary. Though taken from a vein of 
the ear, the blood was of a bright brick-red colour, as it ap- 
peared from the puncture. It would be singular if the ve- 
nous blood of any of the mammals with oval particles should 
not have the usual dark colour. 
The Rhinoceros (52, p. 32.) 1 -2554th is a misprint for 
l-3554th. 
The Red American Fox (24) is the Canis fidvus, not a 
variety of C. Vulpes. 
XIX. On Galvanic Series formed of Zinc and Inactive Iron. 
By Mr. Thomas Hawkins. 
To the Editors of the Philosophical Magazine and Journal. 
Gentlemen, 
NE of Professor Schoenbein’s experiments described at p. 
429 of vol. X. of the L. & E. Phil. Mag., by which he ob- 
tained an electric current of high intensity with wires ‘Tiaving 
one of their ends coated with peroxide of lead, and each end put 
into a separate vessel filled with nitric acid, a hundred times 
diluted,” interested me so much, that I was led, at the time of its 
publication, to make some experiments, with the view of esta- 
blishing the possibility of employing iron in duo. peculiar con-- 
dition as the negative metal in voltaic batteries. After some 
failures I succeeded in forming a galvanic circle with a fine 
iron wire put into nitric acid of sp. gr. 1*5 contained in a tube 
of plaster of Paris, and associated with amalgamated zinc in 
diluted sulphuric acid, which electrolyzed water; and two of 
such circles, in series, liberated the gases rapidly, continuing 
in action for seven hours, when sudden effervescence of the 
acid occurred and the wires were dissolved. Efficient circles, 
but of less permanency, were constructed of iron wires alone, 
having one of their ends in the porous cells of nitric acid, 
the other in diluted sulphuric or even very diluted nitric acid. 
The liability of the iron to be suddenly attacked by the nitric 
acid was prevented, so far as my experience went, by dis- 
solving mercury in the acid, in accordance with the Pro- 
12 
