FIRST COMMUNICATION TO THE SOCIETY. 53 



These results were communicated to this Society in a 

 paper — " Electric Origin of the Heat of Combustion " — 

 read 2nd November, 1841. Of this meeting Mr. B. St. J. B. 

 Joule's diary contains the following note : " I accompanied 

 James to hear his first paper before the Literary and 

 Philosophical Society — Rev. J. J. Taylor in the chair ; 

 Dalton was present, and for the first time in his life moved 

 the thanks of the meeting (and G. W. Wood seconded) to 

 the author of the paper." 



After reading this paper, which was published in the 

 PJiilosopJiical Magazine, Joule was elected a member of 

 this Society, 25th January, 1842. 



At the meeting of the British Association, in Manchester, 

 22nd June, 1842 (at which Joule first meets Scoresby) Joule 

 reads another paper on the same subject, in which he 

 describes further results. The uniform discrepancy of one 

 quarter found in his first determination between the heats 

 of combustion and those of electrolysis he had explained 

 as probably due to loss of heat in his experiments on 

 combustion. This explanation is interesting as con- 

 taining the first intimation of any doubt he has ever 

 cast on any of his experiments. It is also interesting to 

 find that his doubt was wrong, and could only have been 

 momentary, for in this paper before the British Asso- 

 ciation he compares his own results with those of 

 Dulong which are in close agreement, so that the previously 

 observed discrepancies were not owing to error in his 

 measurement of heat. Satisfied of this he has sought, in the 

 meantime, for the cause of the discrepancies in some hitherto 

 unrecognised actions in the cell, and has discovered a 

 discrepancy between the electromotive force engaged in 

 electrolysing the compound bodies and that actually used 



