Sect. IV.] Motmi and Moving Forces. 43 



vering count Rumford* of America. The former 

 states this force, according to his experiments, to 

 be 1000 times as great as tlie mean pressure of 

 the atmosphere ; while the celebrated Daniel Ber- 

 noulli determined it to be not less than 10000 

 times as great. Such a dilference of opinion led 

 count Rumford to pursue a course of experiments, 

 of which some were published in the Philosophical 

 Transactions for 1781, and the remainder in the 

 Transactions of the same Society for 1797; witli 

 the view principally of determining the initial ex- 

 pansive force of Gunpowder, hy one of these ex- 

 periments it appeared, that, calculating even on 

 Mr. Robins's own principles, the force of Gun- 

 powder, instead of being 1 000 times, must at least 

 be 1308 times as great as the mean pressure of 

 the atmosphere. From this experiment the count 

 thought himself warranted in concluding, that the 

 principles assumed by Mr. Robins were erroneous, 

 and that his mode of ascertaining the force of 

 Gunpowder could never satisfactorily determine it. 

 Despairing of success in that way, he resolved to 

 make an attempt for ascertaining this force by ac- 

 tual measurement; and, after many unsuccessful 

 experiments, he was at length led to conclude that 

 this force was at least .50000 times as great as the 

 mean pressure of the atmosphere -j-. 



In addition to the hiquiries of these British phi- 

 losophers, several mgeuious men on the contineiU 

 of Europe contributed to the extension and con- 

 firmation of Robins s theory. Jn this list M. u'An- 



* See Additional Notes — (M). 



-f Runiford's rhilosophical Jj^nsuvf', 8vo. 



