3C8 SALTS 



3. Diniti'ite of lead. When nitric acid is di- 

 gested for a long time on an excess of litharge, 

 a yellow coloured solution is obtained, from 

 which precipitate beautiful yellow coloured crys- 

 tals in small shining scales. The constituents of 

 these crystals are as follows : 



1 atom nitrous acid . 5*75 



2 atoms protoxide of lead 28 



2 atoms water 2-25 



36 



4,. Dmitrate of lead. This salt was obtained 

 by Berzelius by precipitating nitrate of lead by 

 too small a quantity of ammonia to throw down 

 the whole lead. Chevreul obtained it by boiling 

 together equal weights of nitrate of lead and 

 protoxide, filtrating the liquid while hot, and 

 allowing it to crystallize in close vessels. The 

 crystals were pearl coloured scales. This salt is 

 soluble in water, and has the sweet and astrin- 

 gent taste of nitrate. Its constituents are 



1 atom nitric acid . 6- 75 



2 atoms protoxide of lead 28 



34-75 



5. Hyponitrite of lead. Berzelius obtained 



trite, 



this salt by dissolving a given quantity of dini- 

 trite of lead in water, adding as much sulphuric 

 acid as would deprive it of half its lead, filter- 



