436 Experiments and Researches 



Eight ounces of this salt were put into a coated retort con- 

 nected with a receiver, and about four ounces c f nitrous acid 

 were jioured upon it. A pretty brisk action took place, which 

 was further increased l>v the application of heat; fumes of 

 chlorine were immediately disengaged, and a reddish fluid 

 condensed in the receiver ; the heat was continued, and gra- 

 dually raised in a charcoal fire till no acid or moisture any 

 longer came over; at which time a new emission of red fumes 

 indicated that the nitrate formed in the retort was beginning 

 to part with its acid: minute drops of fused salt soon bedewed 

 the upper part and neck of the retort, so as to be mistaken, at 

 first, for a sublimate. This, however, proved to be almost 

 solely muriate of soda ; and on careful examination, it did not 

 appear to contain the smallest atom of corrosive sublimate. 



I next dissolved five or six jjounds of bay-salt in water, and 

 collected in a filter the insoluble earthy sediment, in which 

 Rouelle stated that the quicksilver was usually found. This 

 sediment being careftdly dried, and heated to redness in a 

 coated retort, a white sublimate arose, and condensed on the 

 neck of the retort ; but this sublimate proved to be muriate of 

 ammonia, and did not contain the smallest portion of corrosive 

 sublimate or other mercurial salt. This sal-ammoniac, though 

 evidently formed during the distillation from the vegetable 

 and animal matter contained in the sediment, suggested to me 

 the idea of looking for anunonia amongst the contents of sea- 

 water. 



I now submitted some Sel ilc Gahellc, which I had procured 

 from Calais for the purpose, to similar experiments, and the 

 sediment, also was carefully examined. The result was es- 

 sentially the same as with tiio bay-salt. After adding nitric 

 acid to the salt, the heat was gradually pushed to redness; 

 and when all the moisture was evaporated, a white sublimate 

 appeared, as in the former case, which, in this instance, proved 

 to consist almost entirely of nitrate of soda; but always with- 

 out the least particle of mercurial salt, and without any mu- 

 riate of ammonia*. 



I therefore think myself justified in concluding that the 

 mercury, which other chemists have detected in sea-salt or its 

 products, must have been introduced there from some local 

 or accidental circumstances. 



In experiments upon sea-salt, or in general upon the saline 

 contents of the sea, it is obvious that, in order to exclude 



* In the former experiment tlie sublimate was principally muriate of 

 Koda, owing, no doubt, to the decomposition having been less complete, and 

 the operation less gi'adually conducted than in the latter experiment. 



sources 



