1S14.] Definite Pivpwtlons in Chemical ComlinGlions. 139 



Oxygen (Jxygen 



in the base. in the acid. 



Nitrate of zinc 5 1 



Nitnite of lead 10 2 



1st Subnitrate of lead 5 2 



2d Subnitrate of lead 10 6 



3d Subnitrate of lead 5 6 



Nitrate of nickel 15 3 



Subnitrate of nickel 5 2 



Nitrate of silver 5 1 



Nitrate of mercury 5 1 



Pernitrate of mercury 5 4 



Subnitrate of platinum 5 8 



Nitrate of bismutli 5 1 



Nitrate of uranium 5 3 



It will be seen, by inspecting the preceding table, that the rul^ 

 of Bcrzelius, that the oxygen in the acid is a multiple of that in 

 the base, holds in every case except eight. Several of these excep- 

 tions are sufficiently known to Berzelius ; but it is not necessary to 

 discuss the subject, as that Gentleman admits them, and makes 

 use of them to prove that azote is not a simple bod)', but a com- 

 pound containing oxygen. By this supposition lie reduces the whole 

 of the nitrates under his general law. 



That azote is a compound body can scarcely be doubted. That 

 it contains oxygen is probable, from its little combustibility. The 

 weight which I have been obliged to assign to the atom of azote 

 removes the objection which 1 stated on a former occasion to tliat 

 supposition ; for the weight rS03 shows tliat it may be a compound 

 of 1 atom oxygen ^- 1 atom of a base which weighs 0*803. These 

 reasons render it by no means improbable that Bcrzelius's opinion 

 may be well founded : but it is dangerous in chemistry to admit 

 conclusions from mere theory ; because no part of chemical theory 

 is so well established as to furnish data independent of experiment, 

 Hoilfce azote must remain among the simple bodies, and the 

 nitrates must constitute an exception to Berzclius's law, till some 

 fortunate experimenter succeed in showing us the constituents of 

 azote. Mr. Miers some time ago announced, in the Annals of 

 Philosnp/n/, that he had ascertained it to be a compound of 

 hydrogen and oxygen, and promised to favour us with a detail of 

 his experiments ; but hitherto he has neglected to fulfil his promise. 



I would not be understood, from what 1 have said here, to reject 

 tlie law of Bcrzelius as inconsistent with chemical phenon\ena. 

 The more I have examined it, the mor(! correct, in general, docs 

 it appear; and it seems to promise to throw a new and lively light 

 U|)on the nature of affinity : but it is proper to state and examine 

 all the exee[)tions to any general law, whether real or apparent j 

 because such exceptions never fail in the end to lay open to our view 

 |j(;w secrets of the science under our consideration. 



