Dr. Harems Dejlagrator and Calorimotor. 105 



Letter IV. — From Dr. Hare to the Editor in reply to the 

 preceding letter. 



Philadelphia, May 25, 1822. 

 My Dtar Sir, 



In a former letter you mentioned, that you had found the 

 power of the galvanic defiagrator, when its coils were sub- 

 jected to acid in troughs without partitions, incompatible 

 with the power of other voltaic series, of the usual forms ; 

 that when associated with them in one circuit, it could nei- 

 ther give, nor receive excitement. You now inform me, 

 that this incompatibility is not lessened when the coils are 

 insulated by glass jars.* It follows, that electrical insula- 

 tion has less influence on the action of this instrument, than 

 I had supposed, and it of course confirms my idea, that the 

 deflagrating power is not purely electrical. 



It cannot be doubted, notwithstanding your experiments, 

 that there is a principle of action, common to the various 

 apparatus which you employed, and all other galvanic 

 combinations. The effect of this principle of action how- 

 ever, varies widely according to the number of the series, 

 the size of the members severally, and the energy of the 

 agents interposed. Towards the different extremes of 

 these varieties are De Luc's Column apparently producing 

 pure electricity, and one large galvanic pair, or calorimo- 

 tor of two surfaces, producing, in appearance, only pure 

 caloric. At different points between these, are the series 

 of Davy and Children ; the one gigantic in size, the other 

 in number. In the defiagrator we have another variety, 

 which, with respect to size and number, is susceptible of 

 endless variation. 



It must be evident that no galvanic instrument, where a 

 fluid is employed, could aid, or be aided by, the columns of 

 De Luc or Zamboni. Nor could the influence of either 

 be transmitted by the other. A calorimotor could not aid 

 Davy's great series ; nor could the latter, act through a 

 calorimotor. Taking it for granted that there can be no 

 oversight in your experiments, tjiis incompatibility of ex- 



* See Memoir and engraving in this Journal for February, 1821. Also, in 

 Tilloch's magazine, and the Annals of Philosophy, for April and May, 182L 



Vol. v.— No. 1. U 



