196 REPORTS ON THE STATE OF SCIENCE. — 1916. 



for example that due to the occurrence of faults in the coalfields, is 

 unavoidable, but when all such allowance has been made, there un- 

 doubtedly remains a large wastage in working which might be and 

 ought to be avoided. A memorandum is being prepared on the reduc- 

 tion of such wastage by the adoption of hydraulic stowing, a practice 

 which, although in vogue on the Continent, has not yet been established 

 in Great Britain. 



B. 



Carbonisation Sub-Committee. — Mr. T. Y. Greener (Chairman), 

 Professor P. P. Bedson, Sir G. T. Beilby, Mr. E. Bury, Dr. Charles 

 Carpekter, Dr. J. T. Dunn. Professor Thos. Gray, Mr. D. H. 

 Helps, Mr. C. H. Merz, Professor L. T. O'Shea, Dr. J. E. Stead, 

 Mr. G. Blake Walker, and Dr. E. V. Wheeler. 



The total amount of coal carbonised in this Kingdom for the manu- 

 facture of metallurgical coke or for towns' gas in the year 1913 was 

 probably about thirty-five to forty million tons, or approximately one- 

 fifth of the total home consumption of coal for all purposes. 



According to a recent Parliamentary Return relating to all Autho- 

 rised Gas Undertakings in the United Kingdom, the total quantity of 

 coal carbonised for towns' gas by 831 such undertakings in the year 

 1913 amounted to 16,971,724 tons, from which 195,826 milhon cubic 

 feet of coal gas were produced, or say, on the average, about 11,500 

 cubic feet per ton of coal carbonised. There are a number of gasworks 

 not included in this Parliamentary Eeturn, and it is computed that 

 they carbonise about one and a quarter million tons of coal per annum. 

 Thus the total coal carbonised in gasworks throughout the Kingdom 

 in the year 1913 would be about 18,200,000 tons. 



The amount of ammonium sulphate produced by gasworks in that 

 time in the United Kingdom was officially given as 182,180 tons, which 

 on the above basis would represent an average yield of about 22.4 pounds 

 per ton of coal carbonised. 



No such complete returns are available in relation to the manufac- 

 ture of metallurgical coke, but the amount of coal carbonised for this 

 purpose in 1913 probably did not fall much short of twenty million tons. 

 Of this coal, the larger proportion was carbonised in by-product ovens, 

 producing, besides coke, tar, benzol, &c., some 133,816 tons of 

 ammonium sulphate. Assuming an average yield of 22.5 pounds of 

 ammonium sulphate per ton of coal, it would appear that approximately 

 13.3 million tons were carbonised in by-product ovens, and probably 

 about half that amount in bee-hive ovens. 



With regard to the coking industry, the Sub-Committee has already 

 undertaken steps to secure a complete return of the number of by- 

 product recovery ovens installed and w^orking throughout the country, 

 the character of each installation (whether waste heat or regenerative), 

 its coking capacity, the description of the recovery plant connected 

 with it (whether direct or indirect), the number of benzol recovery 

 plants in operation, the quantities and yields of the by-products obtain- 

 able, and the purposes for which waste heat and surplus gas are being 



