l52 ON AMMONIA. 



XL 



Notes to Dr. Henry*s Paper on Ammonia. By the Author. 

 Communicated in a Letter to the Editor*. 



5Iowne;swith (A.) JI HE fact respecting the slowness, with which ara- 

 which aiwm V jjjoniacal p,-as gives up its water to deliquescent salts, stated 

 yields iis water at page 360, vol. XXIV, oi' the Journal, may be explained, 

 to deiique - [ believe, without ascribing it to any remarkably strong af- 



cent salts not . r- ^ r -ttn • 1 f t 



a proof of nnity or the gas tor water. When sticks oi recently 

 strong affii.ity. fused potash are exposed to ammonia over mercury, they 

 soon become covered with a white incrustation, which appears 

 to prevent the potash beneath from acting on the gas, or ra- 

 ther o_n the water contained in it. It is the iaterposition of 

 this substance, which most probably occasions the slow re- 

 Best dried by moval of the water. The desication, I aftewards found, 

 ^"rodu^'^dT^ may be effected more rapidly by introducing at intervals, 

 quemly. fresh quantities of potash, before it has completely cooled 



from a state of fusion. 

 Gay Lussac In the second volume of the Memoires d'Arcueil, publish- 



findi ew 

 gasses contai; 



" ' ^™ jj^ ed at Paris during the present year (1809), and received by 

 water. Mr. Dalton from the authors since the printi:jg the forego- 



ing paper. Gay Lussac has made, incidentally souie obser- 

 vations on the water contained in gasses. Fluoric acid and 

 perhaps ammoaiacal gasses, he remarks, are free from water 

 of any k nd; muriatic acid from all but combined water, 

 the proportion of which, according to his experiments, does 

 not much diifer from the determination of Mr. Davy; and 

 the remaining gasses contain nothing but hygrometrical wa- 

 ter. The observation is prol)ably correct wuh respect to all 

 but ammoniacal gas. From murmUc acid gas, conhned in 

 a thin glass ^lobe, I have not been' able to obtain any pre- 

 cipilatioi. oi water b) applying a mixture of snow and mu- 

 riate of lime, winch prouuced a temperature ot^ — 2()° i'ah- 

 renntit, aiid not of -J- 26, as mib-pnuted in the text. [p. 

 360, 1 25.] 

 Ammoniacal i^') ^" ^^^ volume of the Arcueil Memoirs, which has 



* These arrived too late for insertion last month. For the paper see 

 Vol.XXlV, p.y58. 



just 



