2 ARGON, A NKW e;ONSTlTUENT OF THE ATMOSPHERE. 



1I.,»>, llio l'iiriiR'it)f wliii'li would l>e retained by the laige excess of alkali einployeil. 

 It was acTordiiii^ly hoped that the ^cas would re(juire no further puritication than 

 diying. If it proved to be light, it would at any rate l)e free from the suspicion 

 of containintr hydrogen. 



The hypobromite was prepaied I'lom eomiiiereial materials in tlie proportions 

 recommended for this analysis of urea — 100 gms. caustic soda, 250 c. c. w-ater, ami 

 2;") c. c. of bromine. For our puii>ose about 1^ times the above (piaiitities were 

 reipiircd. The gas was libei-ated in a bottle of about 900 c. c. capacity in which a 

 vacuum was first established. The full (piantity of hyjwbromite solution w;i.s 

 allowed to run slowly, so that any dissolvetl gas might be at once disengaged. 

 The urea was then fed in, at first in a dilute condition, but as the pressure rose, in a 

 ten per cent solution. The washing out of the apparatus, being effected ^vith gas 

 in a highly rarefied state, made but a slight demand upon the materials. The re- 

 action was well under control, and the gas could be liberated as slowly as desiied. 



In the first experiment the gas was submitted to no other treatment than slow 

 passage through potash and phosphoric anhydride, but it soon became apparent 

 that th(! nitro<,'en was contaminated. The "inert and inodorous" gas attacked 

 vigorously the mercury of the Topler pum[t and wjis described as smelling like a 

 dead ivit. As to the weight, it proved to I)e in excess even of the weight of 

 atmospheric nitrogen. 



The corrosion of the niercuiy and tiie evil smell were in great degree obviated 

 by passing the gas over hot metals. For the fillings of June 6th, 9th, 18th, the gas 

 pa.ssed through a short length of tube containing copper in the form of fine wire 

 heated by a fiat Bunseii l)Uiii('r, then through the furnace over red-hot iron and 

 l)ack over copper oxide. On June 19th the furnace tubes were omitted, the gas 

 being treated with the red-hot copper only. 



The results, reduced so as to correspond with those above (pioted, were : 



June 6th 2.2978 



" 9tli 2.2987 



" 13th 2.2982 



" 19th 22994 



Mean 2. 2985 



Without u<ing heat it has not been found possil)le to prevent the corrosion of 

 the mercury. Kven wdien no urea is emjiloyed and air, simply l>ulil)led through 

 the hypobromite solution, is allowed to pass with constant shaking over mercury 

 contained in a U-tiibe, the surface of tlie metal was soon fouled. When lu/pochlo- 

 rik was substituted for In/pobivmiti in the last experiment theie wivs a decided 



