1822.] Dr. Hare’s improved Deflagrator. 119, 
assume as the equivalent for sulphate of lead, 190 = 1 oxide of 
lead + 1 sulphuric acid, and for that of hydrate of copper, 122°5 
= 1 peroxide of copper + 2 water, the substance would 
approach very nearly toa definite compound of 
2 atoms sulphate of lead equivalent to.. 75°5 
1 atom fiydrate of copper.....--.-s .. 244 
99-9 
H.1. Brooke. 
ArticLe IV. 
Account of Dr. Hare’s improved Dejlagrator, and of the Fusion of 
Charcoal and other Phenomena produced by it. 
A perscription of the instruments invented by Dr. Hare, of 
Philadelphia, and named, the one a Calorimetor, and the other a 
Deflagrator, has been given at p. 176, vol. xiv. and p. 529, vol. 1. 
New Series, of this journal. A correspondence between Dr. 
Hare and Dr. Silliman will appear in the American Journal of 
Science, containing the description of a new Deflagrator, and of 
various interesting phenomena presented by those instruments, 
of which the following is an account drawn up from the letters 
forwarded to the Editor by Dr. Hare. 
From various considerations Dr. Hare was induced to construct 
an instrument consisting of zinc plates surrounded by copper 
cases. The zinc plates were seven inches by three, and the 
copper cases were of such a size as to receive them much in the 
manner of Wollaston’s construction. “There was, however,” says 
Dr.H. “ this apparently slight but really important difference, that 
the cases employed by me were open at top and bottom instead 
ef opposing the edges of the zinc laterally, as in Wollaston’s. One 
hundred galvanic pairs thus made were suspended to two beams, 
each holding 50. Between each case, a piece of pasteboard 
soaked in shell lac varnish was interposed, so that the whole 
constituted a compact mass, into which a fluid could not enter, 
unless through the interstices purposely preserved between the 
copper and the zinc.” This apparatus was equally powerful 
with the original deflagrator, yet its oxidizable surface was not 
of more than half the extent, and it was comprised in one-eighth 
part the space. 
In this construction of apparatus, where two or more beams of 
plates were used, they were fixed side by side in a frame, and 
connected one with another as in the common voltaic instru- 
ment, Then troughs without partitions, one for each beam, 
