Intelligence and Miscellaneous Articles, 235 



quantity of galvanic current except what is caused by the bad con- 

 ducting power of the electrolyte, and the same amount of heat is 

 evolved in a solid and liquid conductor by the same electromotive power 

 if it acts against the same resistance ; but part of the heat so pro- 

 duced is absorbed by the decomposition or separation of the elements. 

 It is not that the galvanic current is diminished by effecting elec- 

 trolysis, otherwise than it is when it passes through a badly conducting 

 solid, for the whole current is effective, and the whole amount of heat 

 due to it is produced ; but simply that part of that heat is rendered 

 latent by the decomposition. 



If a compound body is decomposed without using the battery at 

 all, and that heat is absorbed, or does not make its appearance, that 

 loss of heat cannot be ascribed to diminished intensity of galvanic 

 current. If, for instance, potassium be thrown on water, the oxygen 

 unites with the potassium and the hydrogen escapes, the water being 

 decomposed. Now does the combination of the potassium and 

 oxygen produce as much heat in this case as if the elements were 

 presented to each other in a free state } Decidedly it does ; but the 

 decomposition of the water absorbs part of it and renders it latent : 

 and this quantity so rendered latent is the same as the combination 

 of the oxygen and hydrogen would themselves produce. This is the 

 principle of my discovery. Mr. Joule, in the paper he refers to, 

 published in this Magazine in 1841, does not at any time even hint 

 at an absorption of heat by decomposition, or by anything else. He 

 merely says that decomposition prevents part of the current being 

 effective in producing heat ; so far from saying heat is absorbed, he 

 says it is not evolved at all. His paper would never lead to the sup- 

 position that decomposition produced by superior chemical affinity 

 would cause absorption of heat. That is my discovery, and there- 

 fore I claim to have laid the foundation of all the thermo- chemical 

 researches which take decomposition into account. None were 

 carried on before the publication of my paper in 1 85 1 . 



Mr. Joule says, that, independently of his paper in 1841, he should 

 have priority because he sent a paper to the French Academy in 1846. 

 I do not know exactly the etiquette followed in such cases ; all I 

 know is,'that I worked very hard for a long time to find whether 

 certain theoretical conclusions were experimentally correct ; and 

 finding that they were so, I condensed the labour of months into a 

 short paper and published it, believing it might be of use. This 

 paper having been then made the foundation of other researches, 

 Mr. Joule interferes and says he knew all about it long before I did. 

 I have no doubt oi what he states ; but that knowledge not having 

 been published, did me no good, and perhaps it might still be a dead 

 letter if I had not brought it out by having worked myself. I there- 

 fore think if there is any credit to be attached to the discovery, that 

 I deserve not only my own but his. But as to this paper sent to the 

 French Academy, has it been published exactly as it is in their 

 hands } Perhaps the absorption of heat might not be shown in it at 

 all. I say this, because Mr. Joule brings forward his paper of 1841 

 to prove that he was aware of this truth : and really if I were wish- 

 ing to show proof of his not having at that time known anything 



