Some experiments and researches on the saline contents of sea-water, undertaken with a view to correct and improve its chemical analysis

At the commencement of this paper Dr. Marcet, after adverting to the conclusions at which he arrived in some former researches communicated to this Society, notices the extraordinary assertions of Rouelle and of Proust respecting the existence of mercury in sea water. By a very careful examination, however, of bay salt, he was unable to detect the smallest trace of that metal; nor did he find it in a sample of Sel de Gabelle obtained from Calais for the purpose of examination. Dr. Marcet next examined sea water, with a view of ascertaining whether any nitrates are present in it: with this view he added sulphuric acid and gold leaf to the concentrated bittern, and boiled the mixture, but the metal was not in the least acted on; when, however, the smallest quantity of nitre was added, the gold was instantly dissolved. Hence the absence of nitric salts in sea water may be inferred.