318 Proceedings of the Royal Physical Society. 



selenium, and, further, that it had a very injurious action 

 upon oils. 



This property of selenic acid, the state in which there can 

 be no doubt the selenium exists in the vitriol, of acting upon 

 mineral hydro-carbon oils, has, as far as I am aware, never 

 before been noticed, — the usual bugbear being nitric acid, 

 which, in the case of this vitriol, was shown to be entirely 

 absent. What its exact action is, is rather difficult to say. 

 But the most likely explanation of its action is, that during 

 the process of treating the oils with vitriol, it forms a selenated 

 olefine, which, during the washing with soda, is converted 

 into a sodium-seleno-olefine, and this body on exposure to 

 air, either reddens in colour itself, or acts on the oil in such 

 a manner as to give it a red colour. This is, we know, what 

 happens with sulphuric acid when the oil is overtreated. But, 

 in the case of overtreatment with sulphuric acid, the evil 

 is almost completely removed in the next distillation, while, 

 with selenium, it is not, as the selenium compound distils 

 over along with the oil, and dissolves in it. This was par- 

 ticularly noticed at the worm ends of the burning oil stills, 

 where, when the oil should have been white, it was yellowed 

 to a considerable extent. 



This occurrence of selenium in sulphuric acid, and its 

 action upon oils is as important as it has hitherto been 

 obscure. Important, in so far as by its presence thousands of 

 gallons of oil have been practically rendered unmarketable, 

 and so obscure as to have misled the foremost of our oil works' 

 managers, and the leading chemists in the oil industry. In 

 the benefit accruing to the oil trade from this investigation, 

 Ijersonally I claim but little, but, at the same time, there can 

 be no doubt that the results are of the greatest importance, 

 not only from an intrinsic, but also from a scientific, point of 

 view ; and if, in the credit that is going, I am only bracketed 

 with Mr King and Mr Hunter, I sliall be more than repaid 

 for the part I have taken in the inquiry. 



