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THE ROYAL SOCIETY OF CANADA 



plane parallel clear quartz plates, 1.2 cm. in thickness, and were 

 firmly mounted and waxed in the brass holders mentioned above. 

 Oxygen at a pressure of 140 atmospheres was passed into this tube 

 which was then placed so that the light from the Henri spark passed 

 through the absorbing column of oxygen into the slit of the same 

 Hilger quartz spectrograph as was used before. The spectrogram 

 obtained showed seven bands in the visible region which, as other 

 observers have found, corresponded to the absorption bands obtained 

 with liquid oxygen, although they were not so well marked. A repro- 

 duction of the photograph is shown in Plate I, Fig. 2(a), while the 

 mean wave-lengths of the bands, together with those observed by 

 Liveing and Dewar, are given in Table III. 



In the ultraviolet region a broad band absorption, similar to 

 that obtained in the case of liquid oxygen, was found (shown in 

 Fig. 3 (a), but with this difference, however, that each band was 

 shifted slightly towards the ultraviolet. The bands were again about 

 30 Â.U. in width, and as before, each consisted of a fine set of sym- 

 metrical triplet bands which, in this case, were much more sharply 

 defined, as the reproduction shows. The wave-lengths of the ab- 

 sorption bands were calculated and the results, given in Table lY, are 

 tabulated in the same manner as those in Table II. 



1 Liveing and Dewar, loc. cit. 



