Hare's Calorimotor, 4J9 



in a common recipient without partitions ; there was consider- 

 able intensity of Galvanic action. This shows that, independ- 

 ently of any power of conducting electricity, there is some 

 movement in the solvent fluid which tends to carry forward 

 the Galvanic principle from the copper to the zinc end of the 

 series. I infer that electro-caloric is communicated in this 

 case by circulation, and that in non-elastic fluids the same difli- 

 culty exists as to its retrocession from the positive to the ne- 

 gative end of the series, as is found in the downward passage 

 of caloric through them. 



It ought to be mentioned, that the connecting wire should be 

 placed between the heterogeneous surfaces before their im- 

 mersion, as the most intense ignition takes place immediately 

 afterward. If the connexion be made after the plates are 

 immersed, the eflfect is much less powerful ; and sometimes 

 after two or three immersions the apparatus loses its power, 

 though the action of the solvent should become in the interim 

 much more violent. Without any change in the latter, after 

 the plates have been for some time suspended in the air, they 

 regain their efficacy. I had observed in a Galvanic pile of 

 three hundred pairs of two inches square, a like consequence 

 resulting from a simultaneous immersion of the whole.* The 

 bars holding the plates were balanced by weights, as window- 

 sashes are, so that all the plates could be very quickly dipped. 

 A platina wire, No. 18, was fused into a globule, while the 

 evolution of potassium was demonstrated by a rose-coloured 

 flame arising from some potash which had been placed be- 

 tween the poles. The heat however diminished in a few 

 seconds, though the greater extrication of hydrogen from the 

 plates indicated a more intense chemical action. 



Agreeably to an observation of Dr. Patterson, electrical ex- 

 citement may be detected in the apparatus by the condensing 

 electroscope ; but this is no more than what Volta observed to 

 be the consequence of the contact of heterogeneous metals. 



The thinnest piece of charcoal intercepts the calorific agent, 

 whatever it may be. In order to ascertain this, the inside of 



* See Plate. Fig. 3. 



