212 Dr. Macneveii's Exposition of [Sept. 



acid is three times that of the oxygen in the protoxide for 36-3 

 X 3 = 109-9. 



4. ]\itrous Acid. — This acid is composed of one volume 

 nitrogen and two volumes oxygen. The volume nitrogen 

 = 29-652, as above, and two volumes oxygen, or 33-888 x 2 

 = 67-776. Therefore, the nitrous acid here weighs 29-652 + 

 67-776 = 97-428. But to find the weight of each constituent 

 in 100, we have this proportion 97-428 : 67-776 :: 100 : 69-56, 

 oxygen in 100 nitrous acid, and 100 — 69-56 = 30-44 nitrogen 

 in 100 ditto. Now in order to find the ratio in which the oxy- 

 gen increases in these combinations, we have given the base 

 63-7, and we get the oxygen in nitrous acid belonging to that 

 base by the following proportion : 



30-44 nitrogen : 69-66 oxygen :: 63-7 : 145 oxygen in nitrous 

 acid. The oxygen in nitrous acid is, therefore, four times as 

 much as in the protoxide for 36-3 x 4 = 145-2. 



5. Nitric Acid. — This acid is composed of 1 volume nitrogen 

 and 2*5 volumes oxygen, or by weight of 35-12 nitrogen and 100 

 oxygen. Then to find the oxygen when the nitrogen is 63-7, 

 we have the proportion as 35-12 : 100 :: 63-7 : 181-3 oxygen in 

 nitric acid to 63-7 nitrogen. The oxygen in this combination is 

 five times that in the protoxide, for 36-3 x 5 = 181-5. 



From all these combinations, it may reasonably be assumed 

 that the oxygen enters with the nitrogen into a regular arithme- 

 tical increase from the protoxide upwards : thus, 



Protox. Deulox. Hyponit. Nitrousac. Nitric ac. 

 36-3; 72-7; 109-9; 145-23; 151-3. 



These numbers are to each other as 1,2, 3, 4, 5, very nearly ; 

 hence we may consider the protoxide as the lowest combination, 

 or as a binary, in which one atom of oxygen unites with one 

 atom of nitrogen, and from it the proportional weight of an atom 

 of nitrogen may be obtained, as 36-3 oxygen : 63-7 nitrogen :: 

 1 atom oxygen : 1-75 atom of nitrogen. 



42. P/tosphorus. — According to the experiments of Lavoisier 

 and Davy, 100 parts of phosphorus unite with and condense 154 

 parts oxygen, and form phosphoric acid, which consists, there- 

 fore in a hundred parts, of 39-38 phosphorus and 60*62 oxygen ; 

 but 39-38 : 60-62 :: 1 : 1-54, or else 100 : 154 :: 1 : 1-54. The 

 atom of phosphorus is represented, therefore, by the proportional 

 1-54, or 1-5. Another, but a more complicated method of arriv- 

 ing at the same result is that of examining the neutral salts 

 •which phosphoric acid forms with the different bases. We find 

 then that phosphorus forms with oxygen three acids. 



Pbos. Oxygen. 



Hypophosphorous acid 1-5 + 1 



Phosphorous acid , T5 + 2 



Phosphoric acid 1-5 + 3 



