[shaver] absorption SPECTRUM OF OXYGEN 11 



The experiment was repeated with the absorption tube filled 

 with oxygen at 107 atmospheres pressure. In this case several of 

 the bands in the visible region disappeared, leaving only the three 

 strong bands with wave-lengths X = 6285 Â.U., X = 5800 Â.U;, and 

 X = 4816 A.U., while the ultraviolet bands remained practically 

 unchanged. 



IV. Investigation of the Origin of the Sets of Fine Absorption 

 Bands in the Ultraviolet 



(a) An experiment was performed to determine whether or not 

 the sets of triplet absorption bands in the ultraviolet were due to some 

 impurity in the gaseous or liquid oxygen used. The oxygen gas was 

 guaranteed by the manufacturer to be 98% pure with nitrogen as the 

 impurity, while liquid nitrogen was the most likely impurity in the 

 liquid oxygen. The absorption of nitrogen was, therefore, tried out 

 by using the apparatus described in Section III and passing nitrogen 

 gas into the absorption tube at a pressure of 140 atmospheres. The 

 experiment was performed in the same manner as when the absorption 

 of oxygen gas was obtained, using the spark between aluminium 

 terminals under water as the source of radiation. A photograph was 

 taken of the absorption spectrum of nitrogen, but there was no trace 

 of any absorption whatever showing that the bands obtained with 

 oxygen as the absorbing medium were not due to the nitrogen impurity 

 present. 



(b) It was known from the work of W. N. Hartley,^ and also 

 E. Meyer,^ that ozone strongly absorbs radiations between the wave- 

 lengths X = 28o0 Â.U., and X = 2330 Â.U., and it was thought that a 

 small percentage of ozone might be present in the oxygen causing the 

 band absorption which had been observed. This was the more 

 probable on account of the narrow band absorptions obtained by 

 Professors Fowler and Strutt^ in the region between the wave-lengths 

 X = 3432.2 Â.U. and X = 3089.5 Â.U., using less than 1 per cent, of 

 ozone in oxygen, as it was thought that with a smaller percentage 

 of ozone some bands might appear farther down in the ultraviolet 

 which would account for the absorption bands described in this 

 paper. It has been shown by Regener'* and other observers that 

 light of wave-length X = 1200 A.U. to X = 1800 Â.U. is a powerful 



1 Hartley, Chem. News, p. 268, Nov. 26, 1880. 



2 Meyer, Ann. der Phys., Vol. XII, p. 849, 1903. 



3 Fowler and Strutt, Proc. Roy. Soc. of London, 93, p. 577, 1916-17. 

 * Regener, Ann. der Physik., 20, p. 1033, 1906. 



