a*r4 French Kattoiial Injl'ihite • 



this kind of combination the fuhje6l of his refearches, and in 

 J 79 1 communicated to the academy of fciences a prettv 

 long paper on thefe falts. He edabliihed three kinds of 

 them, diftinguiihed by the proportions of acid and oxide, 

 and he fliowed a difVercnce between them, founded on the 

 ditTej-cnt dates of oxidation of the metal, 



Ditiercnt inlphates are made not only by expofing mercury 

 with lulphuric acid to a Q;reater or Ids heat, and for a longer 

 or iliorter time, but alio bv mixing this acid or a foluble ful- 

 phate with a nitric folution of mercury, more or lefri oxi- 

 dated. If the latter is little oxidated, a white precipitate oj 

 fidphate little oxidated is obtained ; if it be much oxidated 

 a yellow precipitate highly oxidated will be obtained ; ful- 

 phuric acid united to two or three parts of water docs not 

 form fulphate of mercury much oxidated, unlcfs it be con- 

 centrated by long and rtrong ebullition; without this, the 

 water added for wafliing does not render the niixture yellow, 

 and will not make turbilh mineral. The author gives the 

 proportions of the component parts, acid, oxygen and mer- 

 cury, ot the different neutral or acid fulphates, little or very 

 much oxidated. Thefe refultsare a fupplement to his labour 

 of 1791 on this kind of mercurial falts. 



Nitrates of mercury furniflied him with obfcrvations ftill 

 newer and more important for feience than the fulphates. 

 There are two kinds of nitrates, one much oxidated, and the 

 other little oxidated. The former is precipitated, of a gray 

 colour, and almoit black by alkalies, and white by fulphates ; 

 with muriatic acid it forms mercurius dulcis. The nitrate 

 much oxidated, refults from long and ftrong ebullition, gives 

 no precipitate by muriatic acid, it gives a yellow one with ful- 

 phates, a white one with ammonia, and an orange yellow one 

 with iixed alkalies. Nitric folutions of mercury, are often 

 mixtures of the two falts. That which precipitates by water 

 is a folution of oxide much oxidated, or red, in concentra- 

 ted acid. When a nitric folution of mercury, little oxidated, 

 is precipitated by a fixed alkali, the firft portion of the white 

 precipitate, a little coloured, which is obtained. Is a nitrate of 

 mercury infoluble and neutral, formed by the union of the 

 feparated portion of oxide with the remainder of the folution 

 which is not decompofed. What is new in this labour 

 is, the comparifon of the properties of the nitrite of mercury 

 withthofeot the nitrate, Alinoll all folutions contain more 

 or lefs of the former of thefe falts. It is prepared by making 

 nitrous gas pafs into nitric folutions, which greedily abforb 

 it. Super-oxidated nitrate abforbs much more of it than 

 th« nitrate little oxidated. The latter, uitrite of mer- 

 cury. 



