244 Biographical Account of [April, 



writings, and injured their value. But in some of the last essays 

 with which he favoured the world we find mucli valuable and 

 curious information, respecting the heat evolved by different com- 

 bustibles while burning, a subject of great interest, which he pro- 

 secuted for many years, and at last elucidated with considerable 

 success. 



I pass over his quarrel with the managers of the Royal Institu- 

 tion, about the nature of which I am not fully informed, though I 

 suppose it was an attempt on the part of tlie Count to retain in his 

 own hands the entire management of tiiat Institution. Be that as 

 it may, the result of the dispute induced !iim to leave Loudon, to 

 which he never again returned. He settled at Paris, and some 

 years after married the widow of M. Lavoisier, who had retained 

 part of her unfortunate husband's property ; but their tempers 

 were not found to be congenial. Hence after some time they 

 parted. He lived in a house at Auteuil, in the neighbourhood of 

 Paris ; and during the two or three last years of his life, his 

 daughter, who had been brought up in America, hut who came 

 over to join him in France, lived with him in the same house. He 

 died on Sunday, August the 21st, 1814, in the 62d year of his 

 age. His writings, so far as I am acquainted with them, are the 

 following : — 



1. New Experiments on Gunpowder. Phil. Trans, for 1781. 

 P. 229. — This is an elaborate paper. The experiments appear to 

 have been made with great care. His method was similar to that 

 contrived by Robins, and universally known. I can only give a 

 general idea of some of the points which he established. He found, 

 as Robins had done, that when the powder was rammed into the 

 piece the effect vvas greater than when it lay loose, and therefore 

 recommends the use of the ramrod in charging a piece. The force 

 of the charge increased as the piece acquired heat by firing. This 

 is so well known in the navy that, after firing two or three times, it 

 is customary to diminish the quantity of powder used. Our author 

 found that the barrel became much hotter when the piece was only 

 charged with powder than when a ball was employed. He con- 

 ceives the heat to be produced by the vibration of the barrel, and 

 supposes that this vibration will be greatest when there is no l)all, 

 because in that case the action on the barrel is only momentary. 

 Here we have the first notice of our autlior's peculiar notions 

 respecting heat, which he retained during the whole of life. It 

 appears from his experiments that the relative velocities of the 

 bullets, supposing every thing else equal, are in the subduplicate 

 ratio of the weights of the charges nearly. T!>is is conformable to 

 preceding experience. The position of the vent produces very 

 little effect on the charge. He points out a method of proving the 

 relative goodness of powder with i^reat accuracy. But the method 

 h.id been already introduced by Dr. Hutton, and was in use at 

 Woolwich. It consists in having a standard ];owder, the velocity 

 with which a particular charge of which drives a bullet of a given 



