WASTED COAL PRODUCTS. 655 



on which industry must concentrate. As a preHminary, a survey 

 and classification of our coals ought to be made. The term 

 " bituminous " is recommended to be subdivided into " Jong- 

 flame," " normal," and " short-flame," according as the percent- 

 age of volatile matter (i) exceeds 32 per cent., (2) Hes between 

 26 and 32 per cent., and (3) lies between 16 and 26 per cent., 

 respectively. The author also recommends the co-operation of 

 competent chemist and engineer in laying down standard types 

 of plant for treating these three classes, and also for the semi- 

 anthracitic type of African coal. Some of the data of European 

 retorting practice are repeated in the paper. The temperature 

 is about 800 to 1,000 degrees C, and the tar yield is about 4}^ 

 per cent., and in addition about ii/4 per cent, of " benzol " is reco- 

 verable from the gas by efficient extraction. The yield of ammo- 

 nium sulphate is very low in this process, say i per cent., as 

 against 5 or 6 per cent, by the Mond process, a variety of which 

 is in use by the Natal Ammonium, Ltd. Even at pre-war prices 

 for the products there appears to be ample profit in coal-distilla- 

 tion, despite the capital cost. The beehive coking-oven is con- 

 demned, among other reasons, be^cause proper recovery of 

 " benzol " and other volatile bye-products is impossible. For tar- 

 production the Otto-Hilgenstock furnace (heated by waste gas in 

 bunsen-burners ) and the Elliott-Jones retort (which is vertical 

 dnd four inches wider below than above) are specially men- 

 tioned as efficient and economical. 



A fairly low temperature of distillation (500-600 degrees C) 

 tends to increase the yield of tar, and it further appears from 

 small-scale experiments that it is even possible to obtain liquids 

 of the petroleum and " petrol " type from coal by distillation at 

 an even lower temperature inider reduced pressure. In addition, 

 oils suitable for lubrication, and better yields of phenolic sub- 

 stances (for disinfectants) and of pyridine (for denaturing 

 alcohol) result. The yields of these special substances are, of 

 course, small, since tar contains 50 to 70 per cent, of pitch and 

 carbon, and success would depend to some extent on a satisfac- 

 tory disposal of the creosote and anthracene oils which result in 

 much larger, quantity. Similarly, the potential manufacture of 

 aniline for drugs and dyes from benzene is an economic rather 

 than a scientific question. Probably the local market is insuffi- 

 cient, and the aniline would have to go overseas. 



THE EVOLUTION OF A NATIVE ADMINISTRATION. 



By Rev. John Robert Lewis Kingon, M.A., F.R.S.E., F.L.S. 



(Not printed.) 



