ARGON, A NEW CONSTITUENT OF THE ATMOSPIIiafE. 



15 



Tliis I'esiilt was eiu-oiiragini;', altliout;'li weiLijlited with tlic iiiiavnidnhle error 

 attac'liiiii^ to the weighing of a veiy small aiiKumt. Still the fact ifinains tliat 

 the sii[)|H>seil niti'ogeu was heavier tliaii air. It would hardly have been possible 

 to make a mistake of '2.7 milligrammes. 



It is right hei'e to [tlaee on reeord the fact that tliis first experiment was to 

 a gi'eat extent cariied out by Mr. Percy Williams, tt) whose skill in mani2)ulation 

 and great care its success is due, and to whom we desiie hei'e to express our 

 thanks. 



Experiments were now begun on a largei' scale, the appaiatus em[)loyed being 

 shown in Fi^'. 2. 



Fig. 2. 



A and B are large glass gas-holders of about 10 litres capacity. C is an arrange- 

 ment by which gas could be introduced at will into the gas-holdei- A, either by 

 means of an india-rubber tube slipped over the open end of the IJ-tube, or, as 

 shown in the figure, from a test tube. The tube D was half filled with soda-lime 

 («), half with phosphoric anhydi-ide (//). Similarly the tube E, which was kept 

 at a red heat by means of the loug-fiame burner, was filled half with very poi'ous 

 copper (a) I'educed from dusty oxide by heating in hydrogen, half with co[.per 

 oxide in a granular foim (b). The next tube, F, contained granular soda-lime, while 

 G contained magnesium turnings, also heated to bright redness by means of a 

 long-flame burner. H contained phosphoric anhydride, and I soda-lime. All 

 joints were sealed, excepting those connecting the hard-glass tubes E and G, to the 



tubes next them. 



The gas-holder A having been filled with nitrogen, prepared by passing air 

 over red-hot copper, and introduced at C, the gas was slowly passed through th.- 

 system of tubes into the gasholder B, and back again. The magnesium in the 



