ANNALS 



OF 



PHILOSOPHY. 



MAY, 1821. 



Article I. 



Observations on the Combinations of Azote and Oxygen. 

 By Thomas Thomson, MD. FRS. 



ScABCELY any part of chemistry has been investigated with 

 more industry than the various proportions in which oxygen and 

 azote combine. This is partly to be ascribed to the beautiful 

 simphcity which such combinations exhibit, partly to the appa- 

 rent facility of experiments on the union of deutoxide of azote 

 and common air, and partly to the notion entertained by Dr. 

 Priestley and his contemporaries, that common air varies in the 

 proportion of oxygen which it contains, that its state of salu- 

 brity depends upon this proportion, and that the degree of its 

 goodness is easily determined by means of deutoxide of azote. 



Chemists in general are now agreed about the number of 

 compounds of azote and oxygen, which are capable of being 

 formed ; and, with the exception of Mr. Dalton, they are agreed 

 likewise about the exact proportions in which they unite. Mr. 

 Dalton, in a very elaborate paper, published in the ninth volume 

 of the Annals of Philosophy, p. 186, has given us a great number 

 of experiments, from which he draws the following conclusion : 

 the five compounds of azote and oxygen, if we consider both of 

 the constituents in the gaseous form, are composed of 



Volumes. Volumes. 



100 azote + 62 oxygen, constituting protoxide of azote 

 100 + 62 X 2 = 124 deutoxide of azote 



100 + 62 X 3 = 186 hyponitrous acid 



100 + 62 X 4 = 248 nitrous acid 



100 + 62 X 5 = 310 nitric acid 



^ew Series^ vol. i. x 



