VOLTAIC IGNITION. 



337 



were immersed in two separate vessels, in all respects similar 

 to each other, and containing each three ounces of water. 

 A thermometer was placed in the water in each vessel ; the 

 copper wires were connected, so as to form a continued 

 circuit, with a nitric acid battery of eight cells, each plate 

 exposing eight square inches of surface. Upon the circuit 

 being completed the wire in the tube containing oxygen 

 rose to a white heat, while that in the hydrogen was not 



Fig. i. 



visibly ignited ; the temperature of the water, which at the 

 commencement of the experiment was 60 Fahr. in each 

 vessel, rose in five minutes in the water surrounding the tube 

 of hydrogen from 60 to 70, and in that containing oxygen 

 from 60 to 8 1.* 



Before I enter into a farther detail of experiments I would 

 remark upon the extraordinary character of this result. The 

 same current or quantity of electricity passes through two 

 similar portions of wire immersed in the same quantity of 



* After the publication of the Bakerian Lecture my experiment on the pecu- 

 liar effect of hydrogen on the ignited wire was noticed in a paper by M. Matteucci, 

 which, though I had it in my hand shortly after its publication, I regret to say I 

 did "not read with the attention it deserved. I have read it since the experi- 

 ments in this paper were commenced, and I see that I am now executing a task 

 assigned to me by my friend. ' M. Matteucci, for a different object, makes a 

 somewhat similar experiment to the one given above, which, however, differs from 

 mine in the material point, that he operated first on one gas and then on the other, 

 and thus did not compare the effects produced by the same quantity of electricity. 

 I cannot quite agree in the conclusions deduced by him from this and the other 

 experiments he cites, but I will not here contest them, as it would lead me away 

 rom the main point of this paper. 



Z 



