Dana on Electrical Battery. 293 
comparatively small, the instrument occupies a large space, and it 
cannot be readily removed, from place to place, without much 
trouble and risk ; the apparatus is, moreover, very expensive, and 
when one of the j jars is broken another of the same dimensions 
cannot readily be found to supp!y its place. 
It occurred to me, that a Battery might be constructed of 
plates of glass and sheets. of tinfoil, in which the same extent of 
coated surface should occupy a much smaller space, and conse- 
quently that the apparatus would be more convenient and more 
portable. I selected several panes of glass, the surfaces of which 
coincided closely with each other, and then arranged them with 
sheets of tinfoil in this order, viz. pane of glass, sheet of tinfoil, 
then another pain of glass, then a second sheet of tinfoil, and so” 
on; the sheet of foil being smaller than the plates of glass by 
tes inches all around; the glass being 10 by 12, and the foil 6 by 
8. This apparatus contained six plates of tinfoil, and the lowest 
plate being numbered one, was connected with the ground, and by 
slips of tinfoil passing over the edges, with the third plate, and 
this, in like manner with the fifth. The second plate was connected 
with the fourth, and this with the sixth, which communicated with 
the conductor of the machine; in this manner each plate posi- 
tively electrified will be opposed by one negatively electrified, 
and vice versa; the 6th, 4th and 2d plates positive, and the 5th, 
3d, and 1st, negative. Into this apparatus I could introduce a 
Powerful charge, but not possessing a battery of the common form, 
Could not make comparative experiments, The annexed figures 
Will explain the construction of this apparatus. 
: (See Plate.) 
Fig. 1. a1,a2, sie the tinfoil. Fig. 2, @, the intermediate slips pass- 
b b db, plates of glass. ing over the edges of the 
Le, the berets slips con- ines and connecting plates 
n the plates 6, 4, 1, 3, and 5. . 
2. b, the slip which connects the 
d,the — —— 3,1, upper sheet of foil with soe 
and th 4th, &e. 
In a battery of the ordinary form, it is evident that a cia 
less Surface is coated than in one of the above construction ; 
