being a Modification of that recommended, hij Mr. Faraday. 2'1?3 



ber of pairs to form a battery, they are interlaced so that a 

 copper square comes in between each couple of zinc squares, 

 and a zinc square between each couple of copper squares. It 

 is easy to see how this arrangement can be made, when the 

 plates are in the hand, though it is difficult to describe it. At 

 the positive end of the battery there is a single copper plate, 

 which is soldered at the top to the last double copper plate, as 

 seen in fig. 4 ; which figure represents three pairs properly 

 arranged, and also the manner in which they should be fitted 

 up and kept steadily apart in a wooden frame. This frame 

 consists of two cross-bars, e e^ ^ ^, in front, and the same be- 

 hind, dovetailed into solid ends. The channels in the cross- 

 bars, for the reception of the edges of the plates, are formed 

 by placing the four cross-bars together, and sawing a httle 

 way into one side of them all, every eighth of an inch or so in 

 their length, so as to form a set of parallel grooves. We have 

 by means of this frame a much greater security that no me- 

 tallic contact will occur between contiguous plates, than when 

 they are separated by wedges of cork, as in Dr. Hare's con- 

 struction, which may slip out. 



The frame and plates are introduced into a trough, which 

 may be of wood or stoneware, containing the exciting liquor. 

 Dr. Hare's revolving arrangement of the two connected troughs 

 may be adopted for this battery, although we have been led 

 to give a preference in practice to a single trough to contain 

 the frame. To the solid ends of the frame are attached two 

 cords, which are fixed to two pulleys, on which they are wound 

 up, on turning a winch, as represented in fig. 5, by which 

 means the frame and battery can be raised out of the fluid. 

 If the axis (a stout wire) on which these pulleys are fixed 

 can be moved a little backwards and forwards on its bearings, 

 it is easy, by means of a little projecting peg at P, which fits 

 into a hole in the side of the pulley, to fix and support the 

 frame in a position above the trough, and out of the exciting 

 fluid, when that is desirable. But the form of the trough to 

 contain the frame and plates may be varied according to the 

 object in view, or the purposes to which the battery is to be 

 applied. 



In comparing a battery of the form described above, either 

 with Dr. Hare's or any of the other forms in use, it is to be 

 remembered that the plates or elements of the battery are all 

 of double the size they appear to be, or that in this construc- 

 tion you have half the number of pairs, but each of double the 

 dimensions of a pair in any of the old batteries having the same 

 appearance. 



A small battery of this construction, containing twelve pairs, 



2 12 



