776 REPOBT— 1881. 



monoxide 30%, carbon dioxide 3%, and nitrogen, &c., 47% by volume. This 

 gives about 50% by volume of combustible gases, and the calorific power of 100 

 litres is 155,836 gramme-unita of heat. Its calorific intensity is 2,268° C. Ordinary 

 London coal-gas of average composition has a calorific power of 559,038 gramme- 

 units for 100 litres, so that its calorific power is about 3'5 times greater than that 

 of the Dowson gas. Its calorific intensity is 2,564° C. The comparative explosive 

 force of the two gases is as 3-4 : 1, i.e. coal-gas has 3'4 times more energy than 

 the writer's gas ; but because the combustion of the carlx)n monoxide proceeds at a 

 comparatively slow rate, and because of the diluents present in the cylinder, which 

 afiect the weaker gas more than coal-gas, experience has shown that with an Otto 

 engine it is best to allow five volumes of the Dowson gas for one volume of coal-gas. 

 The economical result is that there is a saving of about 50% in the total working 

 cost ; and another practical consideration is that coal-gas requires 220 to 250 tb of 

 coal per 1,000 c. ft. of gas, but the author's requires only 12 It. per 1,000 c. ft., and 

 multiplying this by 5 to give the equivalent power of 1,000 c. ft. of coal-gas, for 

 engine work, there is only 24 to 27% of the weight of coal required for coal-gas, and 

 in many outlying districts this will eftect an appreciable saving in the cost of transport. 

 The results obtained by trials of this gas with a 3J h, p. Otto engine have proved 

 that one h.p. {indicated) per hour is obtained with a consumption of gas derived from 

 1'46 tt). coal, after allomng 10% for impurities and waste of the latter. With 

 engines of larger power the loss due to friction is proportionally less, and the con- 

 sumption of gas per ind. h.p. is less : thus with a 16 h.p. (nominal) engine, which 

 can indicate up to about 40 h.p., the consumption of coal would be only 1-2 lb. per 

 ind. lip. per hour. A practical illustration of the relative working cost of an 

 ordinary steam-engine of the portable type, a gas-engine driven with coal gas, 

 and a gas-engine driven with Dowson gas (in each case indicating 30 h.p.) was 

 given, and this showed that the gas-engine driven with Dowson gas would cost 

 about 45|% less than with coal-gas at .3s. per 1,000 c. ft., and about 47j% less 

 than the steam-engine, consuming 6 lb. of coal per ind. h.p. per hour. Tlie most 

 striking feature, however, was that with the steam-engine 217 tons of coal would 

 be required to give tlie same power as 39 tons of coal converted into gas by the 

 author's process and afterwards used in a gas-engine. This represents a .saving in 

 weiglit of fuel of 88%. For the special reasons given it is best to allow 5 volumes 

 of the author's gas for 1 vol. of ordinary coal-gas when worked with an Otto engine, 

 but in all applications of the gas to heating purposes experience has shown that 

 about 3'5 vols, of this are equal to 1 vol. of coal-gas. If, therefore, the cost of 

 production above stated, for gas made on a small scale, be multiplied by 3'5 there 

 will be a mean of Is. as the total cost of the proved equivalent of 1,000 c. ft. of 

 coal gas for heating purposes. 



4. On Continuous Door-locJis and Footboards for Bailivay Carriages. 



By R. PiCKWELL. 



6. On a new Integrating Anemometer. By the Rev. J. M. Wilson, M.A., 

 and H. S. Hele Shaw. — See Section A, p. 543. 



6. The Advantages of Ex-focal Light in first-order Dioptric Lighthouses. 



By J. R. WiGHAM. 



SATURDAY, SEPTEMBER 3. 



The Section did not meet. 



