4 ARGON, A NEW CONSTITUENT OF THE ATMOSPHERE. 



These numbers, as well as those above quoted for '• atiuospheric nitrogen," are sub- 

 ject to a deduction of O.OOOG for the skrinkage of the globe when exhausted.' If 

 they are then multiplied in the ratio of 2.3108:1.2572, tlit^y will e.xpress the 

 weights of the gas in grammes per litre. Thus, as regards the mean numbers, we 

 find as the weight per litre under standard conditions of chemical nitrogen 1.2505, 

 that of atmospheric nitrogen being 1.2572. 



It is of interest to conii)are the density of nitrogen obtained from chemical 

 compounds with that of oxygen. We have N, lOj = 2.2984 : 2.6276 = 0.87471 ; 

 so that if Og = 16, Nj = 13.9954. Thus when the comparison is with chemical 

 nitrogen the ratio is very nearly that of 16:14. But if " atmospheric nitrogen " be 

 substituted, the ratio of small integers is widely departed from. 



To the above list may be added nitrogen prepared in >et another manner, 

 whose weight has been determined subsequently to the isolation of the new dense 

 constituent of the atmosphere. In this case nitrogen was actually extracted from 

 air by means of magnesium. The nitrogen thus sejjarated w:is then converted into 

 ammonia by action of water ujion the iii.iLTiH'simii nitride and afterwaids liberated 

 in the free state by means of calcium hyi)ochiorite. Tlif [turitication was conducted 

 in the usual way, and included passage over red liol copper and copper oxide. 

 The following was the result: 



Globe empty, Oct. 30th, Nov. 5th 2S2313 



Globe full, Oct. 3 1 St 5 2395 



Weight of gas 2.29918 



It differs inappreciably from the mean of otliei' residts, viz., 2.2990, and is of 

 special interest as relating to gas which at one stage of its history formed part of 

 the atmosphere. Another determination with a different apparatus of the density 

 of "chemical" nitrogen t'luin the same source, magnesium niti'ide, which IkuI l)een 

 prepared by passing "atmospheric" nitrogen over ignited magnesium, may here be 

 recorded. The sample differed from that previously mentioned, inasmuch as it had 

 not been subjected to treatment witli red hot co[)[>er. After treating the nitride 

 with water, the resulting ammonia was distilled off, and collected in hydrochloric 

 acid ; the solution was evaporated to dryness ; the diy ammonium chloride was dis- 

 solved in water, and its concentrated solution added to a freshly prepared solution 

 of sodium hypobromite. The nitrogen was collected in a gas-holder over water 



' "On the Densities of the Principal Gases," Proceedings of the Royal Socieh; vol. LI 1 1, p. 

 134, 1893- 



