£74 WATER IN MURIATIC ACID GAS. 



Common sal- A fact I had ascertained promised to afford a ' satisfactory 

 ftsTrsfpoV haS mode of verif > in S this- The common sublimed muriate of 

 tion of water ammonia, or sal-ammoniac, I had found, yields no water when 

 roanufkctor the ex P osed to a neat sufficient to sublime it. This is owing to its 

 and does not mode of preparation — it is first dried, then sublimed, and, 

 afterwards at- during the sublimation, the upper part of the vessel is kept 

 hot, to render the sublimed mass sufficiently dense, its orifice 

 being also kept open, and hence all the water which can be 

 driven off by this heat is expelled, and none is regained by ex- 

 posure to the air (a decisive proof, if such were wanting, that 

 this salt attracts no water from the atmosphere, since it is kept 

 in the shops without any particular precaution. I exposed 

 •' 100 grains of this salt in a retort to a heat sufficient to produce 

 sublimation, but no moisture appeared during any part of the 

 but it gives experiment. I then sublimed 100 grains of the same salt from 



ont another fa e c \ ose enc j f a porcelain tube, placed across a furnace so as 

 portion in an , . , . ... '.^ - ' . . 



fgnited tube. *° De at a re( * heat. A very sensible quantity of moisture 



condensed in a glass tube, which was adapted to the porcelain 

 one, appearing not only in globules, but at length running down 

 the tube. This proved, that water may be separated from 

 muriate of ammonia by a red heat, which is not expelled from 

 Exp. of sub- it at a lower temperature. I then submitted to a similar expe- 

 the a sal't n of A di- r ' men ^ the salt formed by the direct combination of its de- 

 fect combina- ments. Very little moisture appeared previous to its actual 

 volatilization, but when this commenced, the condensation of 

 water in sensible globules took place j they continued to accu- 

 mulate, and the quantity appeared obviously greater than what, 

 judging from former experiments, would have been obtained by 

 a lower heat from the salt formed from the same quantity of 

 muriatic acid gas. 

 Repetition in 1° another experiment, the salt formed in an exhausted re- 

 an ignited tort was first heated until it ceased to afford water, and was 

 afterwards sublimed through an ignited porcelain tube. Mois- 

 ture was again obtained, though not in so large a quantity as 

 when the charcoal had been placed in the tube. There is no 

 just objection to the introduction of the agency of the charcoal, 

 if care be taken to have it thoroughly calcined j and, as the 

 supposed source of fallacy from the air affording water to the 

 salt, is now proved to have no existence, there is no valid ob- 

 jection 



tube. 



