Remarks on certain Properties of Barytes. 3^7 



This experiment was repeated and varied, at the expenfe of 

 feveral thermometer bulbs ; and it appeared that water may 

 be cooled down in fiich circumftances, not only to 21", but 

 to 5 or 6'^, without freezing, and that the law of expanficn 

 above mentioned obtains in every part of the fcale from 42!" 

 to 10" or below; fo that the denfity of water at 10° is equal 

 to the denfity at 75°, 



LXT. Remarks on certain Properties of Barytes in its Com- 

 bination ivith Mineral Acids ; und on two new Salts never 

 before dejcribed. Bj i.'UvMK, Efq.* 



A^ ROM a number of experiments I have occafionally made 

 on barjytes, but chiefly on it when combined with mineral 

 acids, I have been led to draw fome conclufions and obferve 

 phseuoniena, which, I believe, have hitherto been either to- 

 tally unknown, or fo very imperfeftly detailed, as, no doubt, 

 to have frequently been a fource of error. This earth, for I 

 am not yet difpofed to clafs it with alkalies, certainly poflelfes 

 peculiar habitudes, or rather, when compared with thofe of 

 other earths and alkalies, and its own combinations com- 

 pared with each other, fome fingular anomalies, which I 

 have never yet feen pointed out by chemical writers. 

 Amongft many others, the following appear the moft pro- 

 minent, and therefore demand firft to be noticed. 



1. That fulphate of barytes is completely ycj/z/^/t" in ful- 

 phuric acid ; forming a faliney/w/c/or acidulous fulphate, ana- 

 logous, in fome of its ch a rafter*, to phofphate of lime and 

 many other falts, with capacity for excefs of acid; decom- 

 polable by water alone, which returns it to fimple fulphate; 

 and this fait never has been enumerated by any author. 



2. That carbonate of barytes is alfo totally decompofcd by, 

 and foluble in, fulphuric acid, forming, of courfe, the fame 

 acidulous fulphate. Refptftin^ any figure this new fait may 

 put on, I have not yet been able fully to determine ; but ( 

 flrongly fufpeft it may, under particular circumftances, be 

 made to cryftallize. 



3. That nitrate of barytes, not in cryftals only, but even a 

 faturated aqueou:; folution, is perfedlly infoluble in nitrous 

 acid of the ufual fpecific gravity. 



4. That carbonate of barytes may entirely be changed into 

 nitrate Ijy nitrous acid in its concentrated Hate. The convcrfc 

 of this has hitherto been maintained. 



• Communicared by tlie Author. 



Z3 5. That 



