252 REPORTS ON THE STATE OF SCIENCE. — 1920. 



special order may have effect either generally or as regards particular 

 classes of undertakings, and the provisions of the special order shall 

 have effect as if they were enacted in this section. 



When such official inquiries are instituted by the Board of Trade this Com- 

 mittee wiU hope to be given an opportunity of presenting again its views (as 

 already reported) upon the matters concerned. 



Alcohol from Coke-oven Gas. 



During the past year a notable development has been made in connection 

 with the technology of by-product recovery from coal as the result of Mr. E. 

 Bury's successful experimental trials, in conjunction with Mr. 0. Ollander, at 

 the Skinningrove Iron Works, upon the absorption of ethylene from debenzolised 

 coke-oven ga^ and its conversion into ethyl alcohol. These trials have demon- 

 strated the possibility of obtaining on a large scale 1'6 gallons of absolute alcohol 

 per ton of the particular Durham coal carbonised. Assuming' a similar yield 

 from the 15,000,000 tons (or thereabouts) of coal now annually carbonised in 

 British by-product coke ovens, it is claimed to be possible to obtain from coke 

 works alone a 95 per cent, industrial alcohol in quantities equivalent to about 

 24 million gallons per annum of the absolute spirit. 



Although a f uU account of the investigation has already been given by Messrs. 

 Bury and OUander in a paper before the Cleveland Institution of Engineers in 

 December last (vide also Iron and Coal Trades Review, December 1919), the 

 Committee, whilst not expressing any opinion as to the commercial prospects 

 of the process, considers that the technical importance of it is such as to 

 warrant attention being drawn in this Report to some of its salient features 

 (see Appendix III.). 



The Committee recommends that it be reappointed to continue its investi- 

 gations, with a grant of 35L 



Appendix I. 



Memorandtum upon Coal-inining Statistics. 



The most important statistics concerning coal are the figures giving the 

 annual production of coal, the number of workers employed in the mines, the 

 number of fatal and of non-fatal accidents respectively. These statistics are 

 collected and published by the Government Departments in most coal-producing 

 countries, and upon these are based a number of comparative statements by 

 which the progress of the industry in different countries is usually estimated, 

 such as the production per worker employed, the accident death-rate per thousand 

 workers, etc. For most economic and social studies, the number of workers 

 employed is in several respects the most important of these figures, and un- 

 fortunately it would appear to be the one upon which the least dependence can 

 be placed. Elaborate reports have been drawn up, and legislation has even been 

 enacted, based upon the comparative results of these data ; and it has been quite 

 freely assumed that the figures given for different countries or different districts 

 of a coimtry are properly comparable, whilst as a matter of fact the methods of 

 arriving at these figures vary so widely that they come to bear quite different 

 meanings, and the assumption that similar headings always connote similar 

 interpretations is utterly without foundation. 



Production. — In this country the returns of the output of coal until recently 

 included the stones and dirt sent up to hank with the coal and picked out 

 on the belts or screens ; since that time the weight of coal alone is supposed 

 to be returned. The instructions at present issued by the Home Office read as 

 follows : — 



The weight given should be the net weight after screening or sorting. . . . 

 Where the net weight of the coal is not determined during the year 

 in respect of which the return is being made, it will be sufficient if a 

 deduction is made according to the average percentage of dirt ex- 

 tracted from the coal at the mine. In cases where the coal is sold as 

 it leaves the pit without screening or sorting it will be proper to give 

 the gross weight sent out of the pit as the amount of output. 



