176 DESCRIPTION OF A CLOCK ESCAPEMENT. 



picl or slow combustion, when the liidrogen gas predominates. 

 Into a globe previously exhausted of air I introduced a 

 mixture oFtwo parts of pure liidrogen gas and one of oxigen 

 contaminated with five percent of nitrogen. I detonated these 

 by means of the electric spark ; and then supplied the place 

 of the gasses destroyed by a similar mixture. Having re- 

 peated these operations several times, till the gasses would 

 no longer inflame, in consequence of the superabundance 

 of liidrogen and nitrogen, which gradually accumulated in 

 the globe, I obtained 3*25 gram. [50*2 grs.] of water free 

 from acidity. But this water left by spontaneous evapora- 

 tion about 13 thousHndths of a gramme [0*2 of a gr.] of 

 crystallized nitrate of ammonia; which, being triturated 

 with potash, gave out an evident smell of ammonia, and 

 formed very decided nitrate of potash, 

 titrate of am- I burned very slowly in atmospheric air a stream of hi- 

 monia obtained droeren gas issuing from a gazometer under the mouth of a 

 from various , . i,i * i i /.,,#• tn 



inflammabls glass jar, and collected the water that fell from it after con- 



gasses, densation on the sides of the vessel. This yielded nitr; t • 



of ammonia by spontaneous evaporation, but in less pro- 

 portion than in the preceding process, which was conducted 

 in a close vessel. In like manner I obtained the same salt 

 by combustion of all the oxicarbu retted hidrogen gasses I 

 tried. The formation of ammonia in these combustions is 

 a fact not hitherto observed. 



(To be concluded in our next. J 



II. 



Description of a Clock Escapement: by Mr. Ge«rg* 

 Prior, jun. of Oiley, in Yorkshire.* 



SIR, 



Escapement QlNCE I had the pleasure of seeing you, when my fa- 

 invented, ther and I were in London, I have invented and made the 



• Trans, of Soc. of Arts, vol. XXVII, p. 200. The silver medal and 

 twenty five guineas were voted to Mr. Prior for this invention. 



» machine 



