128 PROCEEDINGS OF SECTION B. 



Scotland.) "The large proportion of mineral matter (21-22 per 

 cent.) will not escape notice ; and it will be perceived that 

 Boghead consists of mineral matter saturated with a hydrocarbon 

 containing a larger proportioxa of hydrogen than there is in benzine 

 Cg Hg." At Joadja Creek the mineral matter falls as low as six 

 per cent., and it is difficult, I should say impossible, to think of 

 six parts of mineral matter " saturated " with ninety-four parts 

 of hydrocarbon, whilst the overlying coal and sandstone, and the 

 underlying coal and sandstone are absolutely free from it. 



The old alchemists used to subject everything organic to 

 distinctive distillation and divide it into water, phlegm, and caput 

 mortuum, and perhaps some information may be gleaned from 

 this industry as now carried out on a large scale. This informa- 

 tion is, however, not very direct owing to the eiiect of varying- 

 temperatures in process, so that the subject is divided into two, 

 namely, high temperature distillation, i.e. gas making, and low 

 temperature, i.e. oil making. In the first the liquid and solid 

 hydrocarbons obtained are mostly composed of the aromatic 

 series, whilst those of the latter belong to the fatty series. The 

 gaseous products may be disregarded in both cases, as they are 

 similar, being hydrogen, methane, and some of the lower olefiines, 

 and mixed, in the case of high temperature work, with the vapours 

 of aromatic hydrocarbons held in gaseous solution. 



In all high temperature work, more gas is produced, than in 

 low, and carbon is deposited whilst aromatic hydrocarbons are 

 formed, as benzol from polymerisation of acetelene below a red 

 heat and its conversion by elimination of hydrogen into naptha- 

 lene at a red heat, whatever the source of the original hydrocarbon. 

 If, however, we look at what is done commercially with various 

 coals and shales we shall find they are not used indiscriminately, 

 but some for one purpose, some for another, according to the value 

 of the products. The statements sometimes found in books are 

 often rather confusing, thus Knapp says — " When submitted to 

 destructive distillation all varieties of coal yield the same solid, 

 liquid, and gaseous products, consisting of coke, tar, ammoniacal 

 liquor, benzole, naphtha, naphthaline, paraffin, paraffin oil, and 

 illuminating gas, the proportions of which vary with the quality of 

 the coal and the temperature employed" (Ronaldsand Richardson's 

 "Knapp's Technology," Vol. I., p. 273.) Laterwriters recognise some 

 difference, thus Mills says — " Cannel tars are poorer in aromatic 

 compounds than are bituminous tars" ("Manualette of Destructive 

 Distillation") and Lunge, — " We may say generally that the tars 

 from peat, brown coal, and bituminous shale consist principally 

 of hydrocarbons of the ' fatty series,' wood tar of phenols and 

 their derivatives, coal tar of aromatic hydrocarbons (" Distillation 

 of Coal Tar," p. 3.) Again — "Brown coal tar as well as that 

 obtained from peat and bituminous shale (and formerly from the 

 Torbane Hill mineral) is manufactured for its own sake as a 



