130 



Xi — Memoir on the Oxides and Nitrates of Lead. ByY. Grace 

 Calvert, Esq., Professor of Chemistry at Manchester. 



Bead, December 11, 1849. 



ACTION OF THE CAUSTIC ALKALIES UPON HYDRATE OP 

 PROTOXIDE OP LEAD. 



Being requested, when in France, to repeat the interesting 

 experiments of Mr. Fremy, upon the compounds which he 

 called plumbites and plumbates of soda and potash, I did 

 so, and was astonished at the difference of action presented 

 by these two alkalies in the same state of causticity. When 

 put in contact with the hydrate of protoxide of lead, soda 

 dissolved three times as much as potash, a result which I 

 did not expect, as it is generally considered that there is only 

 a slight difference in favour of the former. It is probable that 

 the chemists who considered this point before me, did not 

 act under the same circumstances as myself, and that they 

 employed massicot instead of hydrate of oxide of lead, as 

 offering less chance of error. Therefore, from the molecular 

 state of the oxide not being the same, the action of the 

 alkalies must have been different. To ascertain the real 

 solubility, I took a saturated solution of plumbite of soda or 

 potash at 60°, neutralized it with acetic acid, and passed 

 through the liquor a current of hydro-sulphuric acid. The 

 precipitate thus obtained was washed, and its amount de- 

 termined. 



