Art. XIV. On a New Form of the Electrical Battery.

Art. XIV. On a New Form of the Electrical Battery, by J. F. Dana, M. D. Chemical Assistant in Harvard University, and Lecturer on Chemistry and Pharmacy in Dartmouth College.

The Electrical Battery in its common form is an unmanageable and inconvenient apparatus. When the coated surface is 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 jars is broken, another of the same dimensions cannot readily be found to supply 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 consequently 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 pane of glass, then a second sheet of tinfoil, and so on; the sheets of foil being smaller than the plates of glass by two 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 positively 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.)

D^r. J. F. Dana's Electrical Battery.

Fig. 1.	a 1, a 2, &c. the tinfoil.	Fig. 2.	a, the intermediate slips passing over the edges of the glass and connecting plates, 1, 3, and 5.
	b b b, plates of glass.
	c, the intermediate slips connecting the plates 6, 4, and 2.		b, the slip which connects the upper sheet of foil with the 4th, &c.
	d, the slips connecting 5, 3, 1, and the ground.

In a battery of the ordinary form, it is evident that a much less surface is coated than in one of the above construction; in a battery of the common form, two feet long, one foot wide, and ten inches high, and containing 18 coated jars, there will be no more than 3500 square inches of coated surface, while in a battery of the same dimensions on the proposed construction, there will be no less than 8000 square inches covered with tinfoil, allowing the sheet of glass and of foil to be ¼ inch thick.

When plate glass is employed for making this battery, the ring of glass exterior to the tinfoil may be covered with varnish, and then the next plate laid over it; the tinfoil will then be shut out for ever from the access of moisture, and the insulation will remain perfect. This form of the Electrical Battery is very portable, may be packed in a case with the machine, and indeed a powerful battery occupies no greater space than a quarto volume. It is cheap and easily constructed.