476 SCIENCE PROGRESS 



being 24 per cent, for the former, and 19-20 per cent, for the latter. Further, 

 the radiant efficiency is not affected by the draught, though of course more 

 coal is burnt and more heat radiated when the dampers and fender-holes are 

 wide open. The radiant efficiency when anthracite was used instead of coal 

 rose from 24 per cent, to 27 per cent., and with dry coke the figures were 

 slightly higher. Weight for weight dry coke (calorific value 12,800 B.Th.U. 

 per lb.) gave 5 per cent, more radiation than coal (calorific value 14,500). 

 With coke produced by low temperature carbonisation the efficiency increased 

 to 33 per cent., with briquettes it was only 19 per cent., while a good gas fire 

 gives 60 per cent. The patent powders advertised as " doubling the heating 

 value of the coal," etc., had, as might be expected, no effect whatever. They 

 consist mainly of common salt, with small quantities of other sodium and 

 magnesium salts and ferric oxide. 



The design of the grate has an important bearing on the distribution of 

 the heat. The greatest intensity of radiation with all the grates tested was 

 found along an upward line, through the approximate centre of the fire, and 

 inclined at an angle of 60° to the horizontal, but with the old-fashioned 

 barred grate, the variation between 20° and 80° with the horizontal is very 

 small. Thus for the general heating of persons and objects situated some 

 distance from the fire the old type vertical surfaced fire is distinctly the 

 best. The report brings out two other points of great importance in the 

 design of fire-places. First that they should always be set on an inside wall, 

 so that the heat conducted through the fire-back helps to warm adjacent 

 rooms. Secondly, that the grate should be as little recessed as possible. 

 The comparative cost of continuous heating with coal, gas and electricity is 

 worked out in the paper. Taking coal at 45s. per ton, gas at 45. 6d. per 

 1,000 c. ft., and electricity at id. per unit, electricity is five times, and gas three 

 times as expensive as coal, for the same heating capacity in each case. 



The Report of the Metric Committee of the Conjoint Board of Scientific 

 Societies shows, as might be expected, that when the compulsory adoption of 

 the metric system of weights and measures is considered as a possible reality 

 the difficulties become very much more serious, and the advantages much 

 less obvious than they appear when depicted by enthusiastic supporters of the 

 Decimal Association. The Committee is agreed that, if an international 

 system is ultimately adopted, it must unquestionably be a metric system ; 

 but has to point out that in 1913 no less than 54 per cent, of our foreign trade 

 was with non-metric countries of which the most important are China, the 

 U.S.A. and the British Empire. If a change is ever made it will need to be 

 as the result of an agreement with the latter countries. The British system 

 has grown naturally, if haphazardly, with the needs of its users, and is prob- 

 ably better established in their habits than any modern system can be. Its 

 units are of convenient size and, being based on the duodecimal system with 

 its many factors, are infinitely more convenient in use than those of the 

 metric system. Illustrations of this fact are provided by the binary sub- 

 division of weights in metric countries {e.g. the half and quarter kilogram), 

 and by the fractional quotation of prices on the American Stock Exchange 

 in spite of the decimal coinage in that country. The manner in which the 

 British system is commonly used is undoubtedly very clumsy, and there may 

 be confusion in the units employed by different trades, but these defects can 

 be remedied very easily, without introducing the metric system. To these 

 ends the Committee recommends : The abolition of the many unnecessary 

 intermediate units, namely, the league, furlong, and pole ; the grain, dram, 

 stone, quarter, and hundredweight of 112 lb. ; the peck, bushel, quarter, 

 chaldron, and barrel. (2) The abolition of the whole of Apothecaries' Weight. 

 (3) That all areas should be expressed in acres and decimals thereof or in 

 square feet. (4) That the system should be decimalised as far as possible, 

 e.g. that lengths be expressed in miles and decimals of a mile or similarly in 



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