ON FUEL ECONOMY, 109 



the gas might be sold (as proposed by the Board) on a thermal basis, 

 subject to the following provisos: — 



(a) that its methane content shall not be less than 20 per cent., 



its carbonic oxide content not more than 20 per cent., and 

 its content of ' inerts ' not more than 12 per cent. ; 



(b) that its gross calorific value per cubic foot at 60° Fahr. and 



30 in. barometer shall not fall below 450 B.Th.Us- 



Within such limits a gas undertaking would be at liberty to supply for 

 domestic use either (a) ' straight ' coal gas, (b) ' debenzolised ' coke- 

 oven gas, or (c) a mixture of 100 parts of coal gas with (up to) 50 parts 

 of blue water gas. Where, however, gas is supplied in bulk for 

 industrial uses only, a relaxation in the above conditions might be 

 permitted subject to agi'eement as regards cost between gas under- 

 takings and the consumers. 



(12) In conclusion, the Committee hopes that scientific men 

 generally will strongly support the important recommendation made in 

 paragraph 53 of the Board's Eeport in regard to sulphur purification. 

 The Board rightly urges ' the more complete removal not only of the 

 sulphur compounds but also of the cyanogen compounds.' The 

 important investigations carried out, from 1906 onwards, at the South 

 Metropolitan Gas Works by Dr. Charles Carpenter, in conjunction with 

 Messrs. E. V. Evans and Doig Gibb, resulting as they did in a process 

 whereby the sulphur content of the gas sent out from these works 

 has been reduced from 40 to about 8 grains per 100 cubio feet, con- 

 stitute so notable an advance in the technology of gas purification that 

 the time haiS surely come for legislative action in the direction of making 

 such sulphur removal generally compulsory for all large gas under- 

 takings. 



Mr. D. H. Helps, representing the Institution of Gas Engineers on 

 the Committee, dissented from certain of the foregoing conclusions on 

 the grounds that if in future the consumer is charged for gas accord- 

 ing to the number of heat imits supplied to him in it, it will not be 

 necessary to impose upon gas undertakings the restrictions in regard 

 to inert constituents which the Committee has recommended. He was 

 also opposed to the suggested limitation in regard to the carbonic oxide 

 content, as well as to any re-imposition of the obligation upon gas 

 undertakings to remove sulphur impurities other than sulphuretted 

 hydrogen from the gas ; and in regard to the question of pressure he 

 was of opinion that a minimum of li-inch water gauge would be 

 found sufficient. 



During the discussions which took place upon the question of gas 

 standards, the attention of the Committee was called to what is known 

 as the ' stripping of coal gas,' by which is meant the extraction of 

 benzenoid hydrocarbons from it. This process has been instituted as 

 a war measure in view of the necessity for providing sufficient raw 

 material for the manufacture of high explosives. 



It was pointed out to the Committee, however, that with gas selling 

 at its present average price: it would probably be of greater financial 

 advantage to the gas undertaking to allow the benzenoid hydrocarbons 



