276 PROFESSOR CHRISTISON ON THE ACTION OF WATER UPON LEAD. 



body, not previously recognised by chemists. I have since found that MULDER 

 conceives the common carbonate of lead, the white lead of commerce, to be of the 

 same nature. He has recently discovered it to consist sometimes of two, and 

 sometimes of three, equivalents of neutral carbonate, united with one of hydrated 

 oxide ; and he states that the whitest and finest varieties contain most carbonic 

 acid. I find the white lead of this city, which is usually of fine quality, to be a 

 compound of four equivalents of carbonate and one equivalent of hydrate. MULDER 

 adds, that he could not succeed in displacing the whole water by means of car- 

 bonic acid. This may be so ; but the compound formed by the action of distilled 

 water on lead is not similarly constituted. When agitated for two hours in water 

 with a brisk stream of carbonic acid gas, 27.93 grains of the dry product gave, by 

 analysis, 



Oxide of lead, ..... 23.44 grains. 



Carbonic acid (9.27 cubic in.), . . . 4.38 . . . 



Water, ...... 0.15 . . . 



27.97 grains. 



The carbonic acid obtained is only 0.06 of a grain short of what is required to 

 neutralize the oxide. 



