l'KI-:SII)i:.\ ! iAt. ADI^KKSS SKtTlOX A. 



47 



April, loif)) results of lOO tests made on boilers of the Lanca- 

 >Iiire tyi)e, suj)plyinij jKjwer to factories and various industrial 

 concerns in I'.n^land, showed that tlie mean thermal efficiency 

 obtained was ()2.o^^ per cent., and. assuming the h'ii:,h averaj^e 

 indicated tiiermal efficiency of 15 per cent, for the eno^ine, this 

 would give a plant efficiency of 9.3 j)er cent., that is. less than 

 10 per cent, of the heat of the coal is converted into work. It 

 is. however, ])ossible at the present day, in an up-to-date boiler 

 of the water-tube type. sui)plied with auxiliaries such as 

 mechanical .stokers, economisers, superheaters, mechanical 

 draught, automatic dampers, and such scientific guides as auto- 

 matic COo recorders to transfer 80 per cent, of the heat of the 

 coal to the steam. And then the introduction of the comiioimd 

 engine, the steam turbine made in single units up to nearly ^^5,000 

 h.p., and more recently the I'niflow engine, has raised the indi- 



Kk;. 24. — Meat Jun.rjiy Strtain fur Cf impound Coiulcnsiiiy Engine. 



cated thermal etliciency to 2t, jter cent. The diagram. P'ig. 24, 

 taken from I'rofessor Dalby's book on " Steam [•ower," gives an 

 indication of the heat losses in a compotind steam-engine boiler 

 plant. 



From the figures of coal production quoted, it will i)e realised 

 that a saving of even 10 per cent, in boiler efficiency represents 

 an enormous quantity of coal; on the basis of 120,000,000 tons 

 of coal used for power jjroduction in (Ireat Britain a saving 

 greater than the total coal mined in South Africa. 



In giving evidence before the Royal Commissions on Coal 

 Supplies, Dr. Beilby (now Sir (ieorge Beilby), who was Presi- 

 dent of the Chemical Section during the visit of the British 

 Association to South Africa, calculated that, taking the total 

 home consumption of coal in (ireat Britain in that year (1903) 

 as 168 million tons, there w-as a possible saving of 60 per cent. 

 to be obtained by more scientific utilisation. Details are given 

 in Table IX. 



