THE TECHNOLOGIST. 



THE TECHNOLOGY OF SOME OF THE PRODUCTS OF THE 

 DISTILLATION OF COAL. 



BY WILLIAM PROCTER, M.D., F.C.S. 



Some years ago Dr. Ure wrote thus : — " There is not, perhaps, any- 

 waste article of our manufacturing industry which has been so singularly 

 neglected as coal-tar, and yet there can be but very few which offer any- 

 thing like so fair a field for the exercise of skill and ingenuity." At 

 the present time what a different state of things exists ; for there is 

 perhaps no substance which has been, and is being, so fully investigated 

 as Coal-tar, or which has produced results so serviceable to the arts, 

 manufactures, and domestic comfort, or which has shown more fully the 

 value of science in suggesting plans for the utilization of waste sub- 

 stances. We have now large manufactories established solely for the 

 production of Coal-tar, and substances capable of affording it are brought 

 from most distant lands. It is a singular fact that every substance pro- 

 duced by the distillation of these coals, shales, bitumens, &c, has some 

 valuable economic application. Although the illuminating oil is fre- 

 quently the primary object of the manufacturer, the advance of Science 

 has enabled him to utilize a large number of secondary products which 

 would otherwise have been waste. It is to the consideration of these 

 secondary products that this paper is to be devoted. 



When coal-tar is submitted to distillation, a light oil or naphtha in 

 the first instance passes over, then a heavy or dead oil, and, lastly, pitch 

 remains behind in the retort. By distilling in this way there is obtained 

 from 100 parts of coal-tar, about 9 parts of naphtha, 60 parts of dead 

 oil, and 31 parts of pitch. 



In a large number of places in various parts of the world, an inflam- 

 mable liquid exudes, to which the term naphtha is applied, such as 



VOL. IV. A A 



