CBfervations on Strcntfan. 53* 



■' CONTINUATION. 



IN the memoir which I read to the Inflitute the 30th of April lafl;, on the earth known 

 by the name of (Irontian, I remarked, that this earth was, when calcined, very foluble in 

 boiling water, and that a portion became feparated in a cryftalline form by cooling. I alfo 

 remarked, that barytcs acquired by calcination the property of becoming foluble in boiling 

 ■water, and alfo affording cryftals by cooling. It is in this (late of cryftalUzation that ftron- 

 tian and barytes mufl be found pure ; and if they are of the fame nature, as fome chemifts 

 conceive, they ought to give fimilar refults when fubmitted to comparative experiments. 

 It has been thought that the properties which this earth exhibits in its combinations with 

 the acids might be attributed to the prefence of carbonate of lime in the carbonate of ftron- 

 tian ; but calcined ftrontian diflblved in water cannot be fufpeiled to contain hme, and it 

 is therefore in this ftate that I have thought proper to procure fome, in order to examine it 

 comparatively with barytes, which I have alfo taken the pains to prepare in like manner in 

 cryftals, and perfeftly deprived of carbonic acid. 1 fliall here relate to the Inftitute the 

 experiments which I have made on this fubjeft. 



1. I firft put into a fmall capfule fixteen grains of pure cryftallized barytes, with thirty- 

 fix grains [demi-gros] of pure nitric acid of i zl". The combination took place with dif- 

 engagement of caloric, and the cryftals of barytes without being diflblved foon prefente;! 

 jopaque cryftals, which were nitrate of barytes. I added 144 grains [deux gros] of dif- 

 tilled water, and the whole was diffolved. 



2. Sixteen grains of cryftals of ftrontian were treated with thirty-fix grains of the fame 

 acid. The combination took place with difengagement of caloric, but the cryftals were 

 diffolved, and did not become opaque as in the preceding experiment. I added 144. 

 grains of water, in order to have a folution fimilar in ftrength to the former. 



3. A portion of the folution, No. 1, or that of nitrate of barytes prepared with pure 

 barytes, being put into a glafs, I added to it a pretty confiderable quantity of pruiTiate of 

 pot-aft. A precipitation took place, and the liquor was not afterwards precipitated by tlv; 

 addition of carbonate of potafh. 



The other portion of the nitrate being evaporated, afforded cryftals of barytic nitrate ia 

 ocTlahedrons. 



4. A portion of the folution, No. 2, or of the nitrate of pure ftrontian, tried in like man- 

 ner with prufiiate of pot-afli, afforded a flight precipitation 5 but, although I added an ex- 

 cefs of the pruffiate, the fupernatant liquor ftill yielded a pretty abundant precipitate with 

 carbonate of pot-afti. 



The other portion of the folution of nitrate of ftrontian being evaporated, afforded o£ia- 

 hedral cryftals, which were more foluble than thofe of the barytic nitrate. 



5. Fifty- four grains of barytes, pure and in cryftals, being treated with 144 grains [deux 

 gros] of weak nitric acid, the folution took place with heat, but without effervefcence. I 

 added 144 grains of diftilled water, and placed the folution to evaporate in a fand-bath 

 (lightly heated ; and when a portion of the water was evaporated, there were formed cryf- 

 tals in hexagonal plates fimilar to thofe of muriate of barytcs. Their weight was thirty- 

 two grains. 



Twelve grains of this muriate, triturated in a glafs mortar with half an ounce of alcohol, 

 ^■'■'' were 



