ihem. 



200 ARSENIATED HIDR.OGEN GAS. 



fedlion may produce new antl invaluable properties; and that 

 it would be equally impolitic to negledt the ufe of thefe ma- 

 chines, or not to obtain for thera the information to be derived 

 from reflection and experience. We fhall terminate this me- 

 moir by an obfervation relative to their military ufes. Our 

 ^ilitwy ufc of enemies would not fail to oppofe to the creative induflry of 

 of France, an induftry of imitation: they would alfohave their 

 balloons and ballooneers (aerojiiers.) The influence of this 

 innovation in war is of a nature to fpread with rapidity, and 

 it muft foon ceafe to favour any nation excluiively. But even 

 in this cafe the art of aero/latic machines will have acquired a 

 higher degree of interefl, becaufe another element (hall then 

 be in the power of man, in which the efforts of genius and 

 induflry may be fubfliluted inftead of the inconfideratedevafta- 

 tions offeree; and this obfervation ought to interefl the friends 

 of hu-manity in bringing them to perfection. 



VII. 



Schee!e dlf- 

 coveied an in- 

 flammable ar- 

 fcniated gas. 



Its properties. 



Chemical Analyfis and Properties of Arfenialed Hidrogen Gas 

 Bj/ Professor Tromsdorff.* 



JL HE immortal Scheele, in his eflay on arfenic and arfenic 

 acid,+ mentions an inflammable arleniated gazeous fluid, of 

 which he fays: *' Hincintelligas, hunc acrem iiiflammabilan ejje, 

 regulumque arfenici folutum tenere." Scheele ftates, that he ob- 

 tained this gas during the folution of tin in arfenic acid. The 

 properties of this gas, as pointed out by him, are the follow- 

 ing. Arfeniated hidrogen gas is infoluble in water; it does not 

 render lime-water turbid; mingled with atmofpheric air, no 

 diminution of bulk enfues ; on bringing the flame of a taper 

 in conta61 with this mixture, a loud detonation follows, and 

 metallic arfenic is depofited. Interefting as the obfervations 

 here pointed out muft appear to every chemift, the obje6l has 

 been negleded by fucceeding operators. 



* From a memoir, read in the Royal Academy of Sciences at 

 Berlin, 1803, p. 370. 



t C. H. Scheele Om Arfenick och dtfs Syraj Kongl. Svenfk. 

 Vetenflcaps Academiens Handlingar, Ar. 1775. V. xxxvi. 265. 



Prouft 



