Dr. Harems Deflagrator and Calorimotor. 97 



Letter II. — From Dr. Hare, on the peculiar and com- 

 parative effects of the Calorimotor and Deflagrator. Also, 

 an account of an impr^ ved and enlarged Deflagrator, 

 and of some new experiments performed by means of this 

 instrument. 



Philadelphia, March 5, IS22, 

 My Dear Sir, 



In reply to your enquiries on the subject of the Calo- 

 rimotor, and the expediency of employing one during your 

 lectures, it may be proper to mention, that the phenome- 

 na produced by it are more agreeable to the eye and 

 therefore more popular, than any which can be performed 

 without greater difficulty. By the time the Calorimotor is 

 completely immerged in the acid solution, the wire in the 

 forceps is rendered white hot, and takes fire, emitting the 

 most brilliant sfVarks. In the interim, an explosion usual- 

 ly gives notice pf the extrication of hydrogen in a quanti- 

 ty adequate to reach the burning wire. Immediately af- 

 ter the explosion, the hydrogen is reproduced with less in- 

 termixture of air, and rekindles, corruscating from among 

 the forty interstices, and passing from one side of the ma- 

 chine to the other in opposite directions, and at various 

 times, so that the combinations are innumerable. Tiie 

 flame assumes various hues, from the solution of more or 

 less of the metals, and a blazing froth, rolls over the sides 

 of the recipient. When the calorimotor is withdrawn from 

 the acid solution, the surflice appears for many seconds 

 like a sheet of flaming foam. 



I refer you to the last paragraph of my memoir on the 

 Deflagrator, for some results obtained by caiorimotors, of 

 different sizes, which I deem to be scientifically impor- 

 tant.* 



* The heat evolved by one galvanic pair has beea found by the experi- 

 ments which I instituted, to increase in quantit}'^, but to diminish in intensi- 

 ty, as the size of the surface may be enlarged. A pair containing about fifty 

 square feet of each metal, will not fuse platina, nor deflagrate u^on, however 

 small may be the wire employed ; for t!ie heat produced in metallic wires is 

 not improved by a reduction ni their size beyond a certain point. Yet the 

 metals abovementioned, are easily fused or deflagrated by small pairs, which 



Vol, v.— No. U 13 



