NOMOS. 29 



the quantity of hydrogen evolved from the decora- 

 posed water whose oxygen had gone to the zinc 

 (the temperature being 52, and the barometer 29-2 

 inches) amounted to 12*5 cubic inches. This quan- 

 tity, corrected for temperature, pressure, and mois- 

 ture, is equal to 12*15453 cubic inches of dry 

 hydrogen at the mean temperature and pressure. 

 This quantity, increased by one-half for the oxygen 

 which went to make up the water decomposed, and 

 which has entered into combination with the zinc, 

 gives 18 '232 cubic inches of hydrogen and oxygen; 

 and therefore the amount of water decomposed is 

 equal to 2*3535544 grains. Now this quantity of 

 water is to 8*45, the quantity of zinc oxidised, as 9 

 is to 32-31 ; so, taking 9 as the equivalent of water, 

 32*5 becomes the equivalent of zinc: in other 

 words, the decomposition is according to the num- 

 bers of chemical equivalents. It is the same, also, 

 with the decomposition of all other compounds ; but 

 this illustration must suffice. 



There is, moreover, the same definite chemical 

 action at every point of the fluid parts of the circuit, 

 and the same degree of action ; and without the 

 action there is no current. If the platinum poles 

 or electrodes of the battery be immersed in a glass 

 containing; water, some water is decom- 



a . Theconnex- 



posed ; and if the hydrogen and oxvanen on between 



, . . - , . , , , chemical and 



into which the water is decomposed be electrical ac - 

 collected, they are found to be in exact fluid parts of 

 chemical equivalents. The amount of thecircuit - 

 decomposition, moreover, is exactly equal to that 

 which takes place in every cell of the battery, as 



