22 ARGON, A NEW OONSTITITENT OF THE AT:iro.SPHERE. 



nitrogen had l)eeii found to yield u residue of argon. In the course of opeiations an 

 accident occuned, by whicii no gas could have lieen lost, but of such a nature that 

 from 100 to 200 c. c. of air must have entered the woiking vessel. Tlie gas remain- 

 ing at the close of the large scale operations was worked uj) as usual with battery 

 and coil until the si)ectiura showed only slight traces of the nitrogen lines. When 

 cold, the residue measured 4 c. c. This was tiausferred, and after treatment with 

 alkaline ])yrogallate to ivmove oxygen, measured 3.5 c. c. If atm<»spheric nitrogen 

 had been employed, the final residue should have been about 30 c. c. Of the 3.5 

 c. c. actually left, a good part is accounte<l tor by the accident alluded to, and the 

 result I'f the experiment is to show that argon is not formed l)y sparking a mix- 

 ture of oxygen and chemical nitrogen. 



A similar set of expeiiments was carried out with magnesium. The nitrogen, 

 of which three litres were used, was [)iepared by the action c»f l>leaching-powder 

 on ammonium chloride. It was circulated in the usual ai)paratus over red-hot 

 magnesium, until its volume had l>een reduced to about 100 cubic centimetres. An 

 equal volume of hydrogen was then adtled, owing to the impossibility of circula- 

 ting a vacuiun. The circulation then proceeded until all absorption had apparently 

 stopped. The remaining gas was then passed over red-hot copper oxide into the 

 Sprengel's pumj), and collected. As it a[)peared still to contain hydrogen, which 

 had escaped oxidation, owing to its great rarefaction, it was passed over copper 

 oxide for a second and a thinl time. As there was still a lesidue, measiiiing 12.5 

 cubic centimetres, the gas was left in contact with red-hot magnesium for several 

 hours, and then pumped out ; its volume was then 4.5 cubic centimetres. Absorption 

 was, however, still [)roceeding v.hen the experiment terminated, for at a low pres- 

 sure the rate is exceedingly slow. This gas, on being examiiictl with the spectro- 

 scope, contained both hydrogen and nitrogen, and failed to show the red lines of 

 argon. The amount of lesidue attainable from three litres of atmospheric nitrogen 

 should have amounted to a large multiple of the quantity actually obtained. 



8. Separation of Argon on a Large Scale. 



To separate nitrogen from "atmospheric" nitrogen on a large scale, by help 

 of magnesium, several devices weie tiieil. It is not necessary to describe them all 

 in detail. Suffice it to say that an attenq)t was made to cause a store of "atmos- 

 jdieric nitrogen" to circulate by means of a Ian, driven liy a water-motor. The 

 difficulty encountered here was leakage at the bearing of the fan, and the intro- 

 duced air, on coming into contact with the magnesium, produced a cake whicli 

 blocked the tube. It might have been possible to I'emove oxygen by metallic 



