On Galvanic Series formed of Zinc and inactive Iron. 115 



the former the following measurements of the corpuscles were 

 taken. Long diameters, 1 -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 10th. The shorter corpuscles are generally 

 broader in proportion than the others, some nearly circulai", 

 but in this observation none perfectly so. Mr. Siddall's 

 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 CaJiis 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 "having 

 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 the pccidiar 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- 



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