NITROGEN. LORD RAYLEIGH. l6l 



any " remarkably close agreement M or really any agreement 

 for a fundamental atomic weight which is pretended to have 

 been established with marvelous accuracy. 



We see, as a matter of fact, a loiv value from the nitrate, 

 about 14.02 ; a high value from the chlorides, about 14.07 ; 

 and a medium value from the density, 14.06. 



The latest most accurate density determination before 

 the discovery of argon was published by Lord Rayleigh 

 (Journal Chemical Society, vol. 64, pp. 514-515; 1893). We 

 give the actual weights in grammes per liter and divide by 

 the standard atomic weights 16, 14 and i to get the value for 

 the standard ONE : 



Grammes per Liter. Per Unit Atomic Weight. 

 Oxygen, 1.42 961 0.08 935 



Nitrogen (atmosph.), 1.25 749 0.08 982 



Hydrogen, 0.08 991 0.08 991 



We notice that the atomic weight appears not strictly 

 proportional with the density, for the weight per unit of 

 atomic weight is least for oxygen and greatest for hydrogen. 

 This will be found to be a sign of chemical impurity, 

 according to late researches. 



If we calculate the atomic weight of nitrogen from the 

 observed densities here given (Lord Rayleigh's, of 1893), we 

 obtain : 



Oxygen, taken at 16 exactly. 



Nitrogen, I 4-7 34 



Hydrogen, i.oo 62 



Lord Rayleigh's Discovery. 



But Lord Rayleigh discovered that nitrogen obtained by 

 strictly chemical means from ordinary chemical compounds, 

 which gas he termed chemical nitrogen^ invariably gave a 

 decidedly lower density than when he operated upon atmos- 

 pheric nitrogen, that is, nitrogen from the air all operations 

 understood to be conducted so as to obtain pure products, 

 secundum artem. 



This permitted only one conclusion, namely, that one or 



