OXIDES AND NITKATES OF LEAD. 143 



nitrates of lead in which the ammonia is to be considered 

 as water of crystallisation. If so, they would constitute 

 nitrates of lead with five equivalents of elements of crystalli- 

 sation. These views are substantiated by the fact, that I 

 obtained two of the known nitrates of lead, in which a cer- 

 tain quantity of their water of crystallisation is replaced by 

 ammonia, and in which the oxide of lead remained in the 

 original proportions. 



Secondly. It might be supposed that they were double 

 nitrates of lead and ammonia ; but then, heating those salts 

 at a low temperature would not have given water and am- 

 monia, as nitrate of ammonia undergoes by heat a well- 

 known decomposition. And, moreover, it is impossible to 

 admit that the nitric acid of the nitrate of ammonia would 

 have combined itself, when heat was applied, with oxide of 

 lead, and left the ammonia. Before this decomposition 

 could be admitted, it would be requisite to prove that, in the 

 ammoniacal quintibasic nitrate of lead, the nitrate of ammo- 

 nia is combined with a nitrate of lead containing 10 equiva- 

 lents of base. One of the most interesting facts contained in 

 this memoir is the influences which the different modes of 

 precipitation have, in more or less concentrated liquors, and 

 in the composition of the bodies which result from them, 

 as exemplified in a striking manner by the preparation of 

 the preceding salts. The only examples which have any 

 similitude to the above are the preparations of the phos- 

 phates of lime, which also show how molecular arrange- 

 ments are changed by slight differences in the modus ope- 

 randi, and which in my opinion are not often looked upon 

 with sufficient care. 



ACTION OF LIQUID AMMONIA IN EBULLITION ON THE 

 PRECEDING SALTS. 



When the above salts are boiled for several days with 

 liquid ammonia often renewed, besides the white hydrated 



