1813.] Azote, of Hydrogen, and of Ammonia. 281 



parts of yellow oxide. Hence the portion of acid amounts to 

 1-352. 'Hence tliis subsalt is composed of 



Oxide of lead 82*98 



Nitric acid 13-52 



Water of combination 3*50 



100 00 



Now 82-9S of oxide contain 5\993 of oxygen, 13*52 of acid 



contain 11-93, and 8'5 of water contain 3'0S : but — ■— 



= 5-965, and 3-08 x 2 = CrlG. Hence in this salt the acid 

 contains twice as much oxygen as the oxide, and the oxide 

 twice as much as die water. Farther, we find that 135-2 of 

 acid are united with 829 -S of oxide, therefore 100 of acid com- 

 bine with 615 of oxide: but 205*81 x S = 617-43; that is to 

 say. that in this salt the acid is combined with three times as 

 much oxide as in the neutral nitrate. 



I ought to observe that I repeated a second time the prepa- 

 ration and analysis of this subsalt, and obtained as the result 

 82-975 oxide, 3*25 of water, and 13'775 of acid. The slight 

 difference between these two experiments is to be ascribed to 

 the great care and patience necessary to procure the subsalt 

 entirely free from all admixture of the two other subsalts; for 

 when there is a slight excess of ammonia a small quantity of 

 the subnitrate at a maximum is formed: and when too little 

 ammonia has been employed, or a mixture not digested suffi- 

 ciently long, the precipitate is contaminated with the subsalt 

 at a minimum: and in this last case the quantity of water 

 diminishes in proportion as that of the acid augments. 



These experiments prove that the subnitrate at a maximum, 

 of which I have given a description and analysis in my essay 

 already quoted, was in reality merely a mixture of the two 

 Bubnttrates just examined: and consequently that a subnitrate 

 in which the acid saturates 1 1 as much of base as in the neutral 

 nitrate does not exist. 



Nitric, acid, then, has the property of combining with four 

 different proportions of oxide of lead: that is to say, a, with 

 205*81 of oxide, forming the neutral nitrate; b, with twice 

 that quantity = 411*62, forming the subnitrate at a minimum; 



with 20581 x 3 — 617-13, forming the intermediate sub- 

 nitrate; and, finally, d, with 20581 x 6 = 12M/86| forming 

 the subnitrate at a maximum.* As these subnitrates. or at 



• It is proper to observe, thai a mbrilrate In which the acid is eoml ined 

 Com tun. 20V81 <>■' oxide cannot exist, became In thai cue the oxygen 



o*idc- would be a fractional part of thai of the acid. 



