The Rev. N. J. Callan on a ncxo Galvanic Batteri/. 475 

 copper cell, are in the same mercury hole. Fig. 6. represents 

 Fis. 6. 



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the upper surface of the trough by which all the zinc and copper 

 plates are made to act as 20 circles. 



From the preceding description of our battery, it is evident 

 that the whole 20 zinc plates and copper cells may, by substi- 

 tuting one mercury trough for another, be made to act as a single 

 pair, or as 2, 3, 4-, 5, 6, 10, or 20 voltaic circles, and thus be 

 made to supply the place of the calorimotor and of the battery 

 hitherto used for electro-magnetic experiments. 



So enormous is the quantity of electricity circulated by this 

 battery when all the zinc and copperplates act as a single circle, 

 that, on one occasion, after having acted without interruption 

 for more than an hour, it rendered powerfully magnetic an elec- 

 tro-magnet on which were coiled 39 thick, copper wires, each 

 about 35 feet long, while the mercury in which the wires of the 

 zinc plates were immersed, was connected by 6 copper wires, 

 each 1^ of an inch thick and about 6 inches long, with the mercury 

 in communication with the wires of the copper cells. On the 

 fifth day it was tried : after having been in action without in- 

 terruption for more than two hours, this battery melted very 

 rai)iilly plalina wire ^^'gtli of an inch thick, and deflagrated in a 

 most brilliant manner copper and iron wire about j^n^h of an 

 inch thick. 



By this battery, with the aid of an electro-magnet, a current 

 of electricity may be produced which will equal in intensity 

 that of a battery containing 1000 voltaic circles. It is well 

 known that when the connexion between the helix of an elec- 

 tro-magnet and the voltaic battery is broken, a current of elec- 

 tricity is, at the moment of breaking the connexion, made to flow 

 through the helix; and that when the helix is long, that cur- 

 rent is capable of giving a shock to any person who holds in 

 each hand a cop|>er cylinder in conducting communication witi* 

 the ends of the helix. By experiments on the best means of 

 obtaining the shock from the electro-magnet, I have found tliat 

 the shock increases, within certain limits, with the length and 

 ihinnessofthebar of soft iron,andwitli the length of the heliacal 

 coil, as far perhaps as 200 feet, and in proportion, or nearly in 

 proportion, to the lumiber of plates in the voltaic battery from 

 which the current of electricity is passed through the helix. 

 The shock does not increase in proportion to the number 

 3 L 2 



