110 Mr. Richard P,hil/ips on the [Feb. 



for the curious discovery which he had made. Although I was awaref > 

 of the crystaUization of hme whicli M. Gay-Lussac had effected 

 by the agency of sulphuric acid and a vacuum ; and after 1 had 

 looked in vain to the authors whom I have quoted, in order to 

 discover whether they were aware of the crystallization of lime 

 which takes place by heating, I found that M. Thenaid had 

 stated the fact in his Traite de Chimie ; however as he has , 

 not given any account of the extent to which it takes place^/ 

 nor apphed it to explain the greater solubihtyof hme in cold water, 

 I have thought the details now given not altogether devoid of 

 interest. 



Article VI. 



On the Bicarbonate of Ammonia. By Richard Phillips, 

 FRSE. FLS. &c. 



In the seventh volume of the Journal of Literature, Science, 

 and the Arts, I have given an analysis of the salt usually called 

 subcarbonate of ammonia. I traced also the nature of the 

 decomposition by which muriate of ammonia is converted by 

 the action of carbonate of lime, first into sesquicarbonate, and 

 eventually into bicarbonate of ammonia. This last salt I had 

 not at that time seen produced, except by exposing sesquicar- 

 bonate of ammonia to the atmosphere. During the last summer, 

 however. Dr. Henry gave me some salt which had been prepared 

 with the intention of producing the common smelhng salts. 

 From some cause which has not been explained, the salt instead 

 of being pungent had scarcely any smell whatever, and was on 

 this account rejected by those to whom it was sent. This salt 

 is more crystalline in its texture than the sesquicarbonate of 

 ammonia : it does not become opaque by keeping ; and turmeric 

 aper held over it is scarcely affected by it even when fresh 

 roken. 



Dr. Henry informed me that he had found this salt to be 

 bicarbonate, but not having given me the particulars of his ana- 

 lysis, I venture to state the results of my own experiments. 



One hundred and twenty parts of the salt were dissolved in 

 dilute sulphuric acid, the Vveight of the vial and acid being pre- 

 viously noted. The quantity of carbonic acid evolved amounted 

 to QQ'h parts, equivalent to 55'5 per cent. An equal quantity 

 of the same salt was dissolved in water, and added to a neutral 

 solution of nitrate of lime, taking care that the latter salt was 

 excess. Effervescence readily occurred, and by the application 

 of a gentle heat, carbonate of lime was precipitated : this after 

 being^washed, was dried, and weighed 74*4 = 62 per cent. 

 By Dr. Woilaston's scale, it will be seen that 62 of carbonate 



I 



