412 Dr. T. M. Lowry on an 



It is as well, perhaps, again to emphasise the fact that the 



values for Fjr given above depend on two factors which are 



usually assumed to be inseparable — the solubility-factor and 

 the "nature-of-the-gas-factor," — although there are a priori, 

 grounds for presuming that the solubility-factor contributes 

 but little to the total effect. Whilst writing the above, 

 however^ it appeared to the writer that the two factors might 

 be separated by observations of the surface-tension made at 

 temperatures at or near the boiling-points of the liquids in 

 question, when the effect of the solubility-factor would pre- 

 sumably be inappreciable. It is hoped shortly to communicate 

 results dealing with this point. 



University College of North Wales, Bangor. 

 July 1914. 



XLVI1I. An Oxidizable Variety of .Nitrogen. 

 By T. Martin Lowry, D'.Sc* 

 [Plates VIII.-XI.] 

 ri'HE photographs which are reproduced in the present 

 JL paper are of interest both from the spectroscopic and 

 from the chemical point of view. On the spectroscopic side 

 they represent an application of this method of investigation 

 to gases which were so dilute that a column of gas 64 feet 

 in length was required to produce an adequate absorption. 

 On the chemical side they produce evidence, which appears 

 to be unique, of the existence of an oxidizable modification 

 of nitrogen, an allotropic form of the element which is 

 perhaps the first essential product in its fixation. A brief 

 summary of the conclusions arrived at has been published in 

 the i Transactions' of the Chemical Society f, but the photo- 

 graphic evidence on which those conclusions were based is 

 now reproduced for the first time as as a contribution to a 

 subject which has figured frequently in preceding volumes 

 of the ' Transactions ' of the Faraday Society. 



The gases under investigation were obtained by the action 

 of the electric discharge on air. Two forms of discharge 

 were used. First, the " silent " discharge in a large 

 Andreoli ozonizer containing sheets and grids of aluminium, 

 thirteen in number and 30 in. x 30 in. in area, separated by 

 sheets of micanite. Second, a sparking discharge between a 

 series of iron studs separated to a distance of -fy i ncn - Three 

 groups of 6 spark-gaps and two of the Andreoli ozonizers 

 were used at various times. 



* Communicated by the Author. From the ' Transactions ' of the 

 Faraday Society, July" 1913. 

 t Trans, ci. pp. 1152-58 (1912). 



