»E3T CONSTRUCTION OF A TOLTAIC APPARATUS. ]5J 



with plates of copper and zinc, connected together by leaden the new me- 

 Straps, soldered on the top of each pair of plates; which are thod * 

 twenty in number, and each plate four feet high, by two . a !f s ° eet 

 feet wide: the sum of all the surfaces being 92160 square Surface qoig 

 inches, exclusive of the single plate at each end of the bat- square incUw. 

 tery. The trough is made of wood, with wooden partitions 

 well covered with cement, to render them perfectly tight, §0 

 that no water can flow from one cell to another. The bat- 

 tery was charged with a mixture of three parts fuming ni- 

 trous, and one part sulphuric acid, diluted with thirty parts 

 of water, and the quantity used was 120 gallons. 



In the presence, and with the kind assistance of Messrs. 

 Davy, Allen, and Pepys, the following experiments were 

 made. 



Experiment 1. Eighteen inches of platina wire, of ^o{ Its effects. 

 an inch diameter, were completely fused in about twenty 

 seconds. 



Exp. 2. Three feet of the same wire were heated to a 

 bright red, visible by strong day-light. 



Exp. 3. Four feet of the same wire were rendered very 

 hot; but not perceptibly red by day -light. In the dark, it 

 would probably have appeared red throughout. 



Exp. 4. Charcoal burnt with intense brilliancy. 



Exp. 5. On iron wire, of about -^th of an inch diame r 

 ter, the effect was strikingly feeble. It barely fused ten 

 inches, and had not power to ignite three feet. 



Exp. 6. Imperfect conductors were next submitted to 

 the action of the battery, and barytes, mixed with the red 

 oxide of mercury, and made into a paste with pipe-clay and 

 water, was placed in the circuit; but neither on this, nor on 

 any other similar substance, was the slightest effect pro- 

 duced. 



Exp. 7. The gold leaves of the electrometer were not 

 affected. 



Exp. 8. When the cuticle was dry, no shock was given by 

 this battery, and even though the skin was wet, it was 

 scarcely perceptible. 



Before I offer any observations on the inferences to be 

 drawn from these experiments, I shall mention some pthers, 

 performed, for the sake of comparison with the foregoing, 



with 



