378 Account of soyne Experiments 



trouble and less heat; the action indeed at first is so power- 

 ful, that gas begins lo confie over before the application of 

 heat is made, and a very gentle one only is required to con- 

 tinue its production. 



Previous to its analysis, it was necessarv to ascertain the 

 specific gravity of the gas. This I have endeavoured to 

 do. The gas, the subject of experiment, was quite pure, 

 being totally condensed by water. A florence flask was 

 exhausted j in this state, weighed by a very delicate balance, 



it was = 1452-2 grains. 



Filled with common air = 1452"2 + 10*2. 



Again exhausted = 1432*2 



Fdled with silioated fluoric gas = 1452-2 -f 36-45 



Hence as l()-2 : 31 : : 36-45 T: 110-78. 



Thus it appears that lOO cubic inches of silicated fluoric 

 acid gas, at ordinary temperature and pressure, are equal to 

 IJO-fs grains. 



When silicated fluoric acid gas is condensed by water, it 

 is well known that part onlv of the siles is deposited. To 

 obtain the whole, in order to ascertain the proportion in 

 the ga-, I have employed ammonia in excess. 40 cubic 

 inclies of the gas (barnm. 30°, therm. 60') were transferred 

 in portions of 10 cubic inches- at a lime to a solution of 

 ammonia. The silex precipitated was carefully collected 

 on a fiber, and washe.-d till the water that passed through it 

 ceased to be affected by nitrat of lime, ll was next dried, 

 and strongly heated in a platina crucible. It weighed 27 '2 

 grains, and was pure silex. Supposing fluoric acid to be 

 the remaining 17-I grains, which added to 27-2 grains are 

 equivalent to the weight of 40 cubic inches of the gas, it 

 appears that 100 parts by weight of this gas consist cf 

 61-4 silex 

 38-6 fluoric acid 



100-0 

 That this estimate may be correct, it is evident, that am- 

 monia should have the property of prccipitatinir the whole 

 of the silex of silicated fluoric gas ; which I shall not now 

 endeavour to prove, but leave it to be, considered in another 

 ];arr of the paper. 



There is t)0 improbability attached to the idea, that sili- 

 cated fluoric acid gas may, from the manner in which it is 

 prepared, coiitain a proportion of alkali. To discover 

 whether this was the case, a solution of nitrat of hme was 

 added to the annnoniacal solution neutralized by nitric 

 acidj from which the silex iu the preceding experiment had 

 ■ ' been 



