228 Scientific Intelligence. [March, 



phuretted hydrogen gas, the remainder will be the weight of 

 phosphorus existing in a volume of phosphuretted hydrogen gafe^ 



Specific gravity of phosph. hydrogen 0*9022 

 Specific gravity of hydrogen 0-0694 



Phosphorus = 0-8328 



This number 0-8328 may be considered as the specific gravity 

 of a volume of phosphorus in the state of vapour. We have 

 then phosphorous acid composed of 



1 volume vapour of phosphorus .. = 0-8328 

 ■^ volume of oxygen gas = 0-5555 



But 8328 : 5555 :: 1-5 : 1 very nearly. Hence it follows, that if 

 an atom of phosphorus weighs 1-5, phosphorous acid is a com- 

 pound of one atom phosphorus + one atom oxygen ; and that 

 the weignt of an integrant particle of it is 2-5. 

 Phosphoric acid is composed of 



1 volume vapour of phosphorus. . . = 0-8328 

 1 volume oxygen gas = 1*1111 



But 8328 : mil :: 1-5 : 2 very nearly. Therefore phosphoric 

 acid is a compound of one atom phosphorus = 1-5 and two 

 atoms oxygen = 2 ; and the weight of an integrant particle of 

 it is 3*5. 



There exists but little difference of opinion between Berzelius 

 and myself respecting the composition of phosphoric acid. The 

 numbers resulting from my experiments are, 



Phosphorus 100 



Oxygen 133-i- 



While the numbers of Berzelius are, 



Phosphorus 100-00 



Oxygen 128-17 



Now my numbers are corroborated by the direct experiments 

 of Sir Humphry Davy, who found that 100 phosphorus, when 

 burned in a high temperature, absorbed 135 of oxygen. The 

 mean of the experiments of Berzelius and Davy gives us the 

 following numbers for the constituents of phosphoric acid : 



Phosphorus 100-00 



Oxygen 131-58 



These facts seem to me to lead us without any hesitation to 

 admit phosphoric acid to be a compound of 1 atom phosphorus 

 s= 1*5 + 2 atoms oxygen = 2, 



It is with respect to the composition of phosphorous acid that 



