﻿Energy of the Amperian Molecule. 



481 



heat flowed through the pile. By passing hot or cold water 

 through holes in the pole-pieces we were able to alter the 

 flow at will. The following are the results obtained : — 



Table II. 





Effect observed. 



Seconds after altering field 







5 



15 



30 



Warm water passed for about 



20 minutes and then stopped. 



After 5 minutes 



o oo poop 

 6 <z><i> oooo 



-0-33 

 -012 

 -014 

 -013 



+001 

 +004 



-011 



-0-73 

 -042 

 -025 

 -0-16 



+015 

 + 0-11 



-020 



-0-87 

 -0-50 

 -0-26 

 -013 



+015 

 +022 



-015 



After 25 minutes 



After 45 minutes 



Ice-cold water passed through 



next day and kept flowing . . . 



20 minutes later 



Water stopped. 

 20 minutes later 





These numbers are each the mean of ten determinations, 

 and show clearly the alteration of sign from — to + as the 

 flow of heat changed from the iron-pile to the pile-iron direc- 

 tion. They accord with the sign of a set of readings we took, 

 in which the end of the pile remote from the iron was warmed 

 by a tube carrying a stream of tepid water (curve /) ; and 

 they also explain the change of sign which occurred while 

 the paraffin slab was cooling (p. 479). 



Having thus traced our first results to the unsymmetrical 

 arrangement of the pile, the obvious course was to put it in 

 such a position that the flow of heat through it was avoided 

 altogether, and to repeat our original readings. This we tried 

 to do, but without success. It was easy to reduce the flow to a 

 very small amount, but quite impossible to keep it so for more 

 than a few minutes at a time. We venture to think, however, 

 that the curves obtained are sufficient to prove the absence of 

 the molecular effect sought for. A comparison of the curve 

 for artificial heating with the others shows that the peak, 

 which is so marked a feature in the former, is not found in 

 the latter. It is true that if only the normal curves b, e, d, e 

 are considered, it might be urged that the peak is perhaps 

 absent because it is neutralized by an equal and opposite peak 

 in the effect which gives the readings their negative sign. 

 But if this were so, it should be doubly present in the curves 



