TRANSACTIONS OF THE SECTIONS. 95 
d, unassisted, hope to achieve, would be to simplify and improve 
ly its various portions. 
Any one, he observed, who had experimented on a large scale, must 
found that the galvanic apparatus becomes considerable in size, 
troublesome in operation ; he had determined, therefore, to devote 
ome time to the construction of a machine, from which we might 
obtain electricity of very high intensity, to be applied, if possible, to 
the magnetization of bars of soft iron. He was aware that a consider- 
able effect was said to have been produced by a battery consisting 
‘merely of a wire of zine, and another of platina, and a small quantity 
of acid ; but as there is no standard for the measure of physiological 
effects but the variable susceptibility of individuals, he could not but 
think, from a variety of experiments he had made, that the shock was 
Rieuified by the surprise of the experimentalist, as we know it to have 
been at the discovery of the principle of the Leyden jar: of the power 
_ of the apparatus before it the Section could judge for itself. Its con- 
struction was simple and permanent ; and, from the ease with which it 
could be applied, and the power we possess of diminishing, at pleasure, 
the number and intensity of the shocks, it appeared well calculated 
for the purposes of medical electricity. It is self-acting ; and as it 
‘ oo no aid from the operator for the production of continued 
electrical effects, when once excited, it leaves his attention undivided 
for experiment. Besides the arrangement of its parts, which he be- 
A ieved to be the best of any he had tried, and which he would detail 
to the Section, he was inclined to attribute its efficiency to a number of 
‘circumstances he had not yet sufficient time to develope, and whose 
consideration, therefore, he would leave to another opportunity. 
; wwi is a bar of soft iron 2 feet long, 3-4ths of an inch in diameter. 
AS and B two helices, each about 580 Ve long, No. 13 copper wire, 
nposed alternately on the other. H aie P are mercury cups, con- 
ected with cylinders of copper S and T, for giving the shock, and 
ith the extremities of helix B. K and O mercury cups, connected 
with helix A. N, and the same cup O, connected with the poles 
of a small calorimeter; D a copper wire, carrying a soft iron knob 
be attracted by the bar W W, and, when attracted, to draw down 
lever Z E, turning on the centre C, and having fixed on its longer 
1 the curved wire E, which, being elevated or depressed, makes 
