205 



The differences will be still more striking, if it be further assumed, 

 that the projective force is not only dependent on the pressure at the 

 time of the explosion, but also on the specific gravity of the gases, or 

 what may be termed their energy; and that, in regard to gunpowder, 

 this effect is considerably lessened by the fact, that, when the explo- 

 sion takes place in a vessel that yields before the maximum force is 

 attained, a considerable proportion of the powder is thrown out be- 

 fore it can act or be ignited; while, with liquids, the ignition of the 

 whole mass is instantaneous. Mr. B. had no doubt that, in this re- 

 spect, the force of the perchloratc of the oxide of ethule might be 

 considered more than ten times as great as that of gunpowder. It 

 would also be evident from these considerations, that, in this same 

 respect, the chloride of nitrogen, although considerably inferior to the 

 perchlorates, still greatly surpasses gunpowder ; and that a prevalent 

 opinion to the contrary must be founded in a deception, probably 

 arising from the smallness of the quantities of this dangerous sub- 

 stance which can be employed with safety in experiments. 



The Committee appointed at the adjourned meeting of the 

 5th of July, to report in relation to the proper course to be 

 pursued for the protection of the trust funds of the Society, 

 made a report, which was recommitted to the same Commit- 

 tee, with instructions to report at an adjourned meeting, to be 

 held on Friday evening next. 



The following gentlemen were elected members of the So- 

 ciety: — 



Petty Vaughan, of London. 



Frederick Fralet, of Philadelphia. 



Adjourned Meeting, July 22. 



Present, thirty-five members. 



Dr. Patterson, Vice-President, in the Chair. 



The report of the Committee on the Museum property, 

 under the resolution passed at the adjourned meeting of the 

 5th of July, was read, and the Society adopted the recommen- 

 dations contained therein; namely, that the several instru- 

 2 A 



