66 



The question of the origin of sulphur !n oils and shales is 

 closely connected with the theories of the origin of oils. In the pro- 

 cess of the decay of marine animal matters the sulphur compounds 

 formed by tu.e decomposition of the protein constituents are con- 

 verted into gaseous and soluble products and some of these, during 

 the formation of liquid oils, may have interacted with the hydro- 

 carbons, more easily the unsaturated, and so introduced sulphur 

 into the oils. Where the oil or shale contains considerable quan- 

 tities of sulphur a further mode of introduction from an outside 

 inorganic source is probable during a secondary process. That 

 gypsum, calcium sulphate, may be the source of the abnormal 

 quantities of sulphur in the Kimmeridge shale oil occurred to the 

 present writer, and it appears that the idea has also suggested 

 itself to others in similar cases. An analysis of samples of 

 Kimmeridge shale gave a value for Ca O (lime) at 12 per cent, and 

 for S. at 6.5 per cent. : the ratio of Ca O to S. in gypsum is as 12 

 to 7 ; a very close agreement. Perhaps further work will snow 

 whether there is any firm basis for this suggestion. 



In connection with this it is interesting to point cut that 

 Scotch shales contain very little Ca O (lime) and the oil but slight 

 traces of sulphur. Partly as a further illustration, but more as a 

 chemical curiosity connected with the subier.t. will be now quoted 

 an old analysis as given in Burton Green's monograph of Kim- 

 meridge shale. 



Analysis of the Residue Shale or " Carbon " 

 Soluble bone phosphate 0.39 Organic sulohate of lime 5.08 



Burned animal matter 4.85 Sulphide of lime 4.22 



Organic nitrogen 2.95 Silica 4.59 



Phosphate of lime 1.37 Hydrogen 7 



Carbon 48.12 Alkaline oxides 5.15 



Vegetable matter 12.50 Naphtha 3.5* 



— .04 



Notwithstanding the inexplicable and curious items of the 

 anaysis, one fact is evident, namely, the high proportions of the 

 "sulphate" and " sulphides of lime." Dr. F. M. Perkm, in his 

 valuable paper " Sulphur in Petroleum Oils " read at the Institute 

 of Petroleum Technologists in March, 1917, called attention to a 

 fact which illustrates the point now urged. He believed that it is 

 generally found that larger amounts of sulohur are found in oils 

 obtained from limestone regions than from those where the 

 geological formation is siliceous. 



Types of Sulphur Compounds in Oils. 



Several classes of sulphur compounds have been recognised 

 and isolated from various mineral oils. Indeed practically all 

 existing types of organic sulphur bodies are represented and one 

 particular class, the thiophanes, were actually "first isolated from 

 some North Americal oil five years before some of them were 

 synthetically prepared, and now practically the whole class has 

 been synthesised and its generic properties fully investigated. 



