64 PRKSIDKNTIAI, ADDRKSS SECTION A. 



Il must not, lujwcver, l)e imagined that the Diesel engine 

 is entirely dependent upon petroleum and tar oils. Animal and 

 vegetable oils may he used directl}' in Diesel motors. Experi- 

 ments have been carried out on a great variety of fuels, includ- 

 ing petrol. ])aratYin, ordinary crude petroleitm. the residuum 

 from crude ]jetroleum distillation. ])alm and nut oils, castor oil. 

 fish oil, alcohol, coal gas and ])roducer gas. Special attention 

 has frequently been directed to African Cjround Nuts as a 

 source of Diesel motor fuel. I am also assured on reliable 

 authority that there are inmiense deposits of suitable oil shale in 

 the Wakkerstroom district. The (}uestion is a most important 

 one. No work having more far-reaching elTects could be 

 imdertaken by the newly- formed Scientific and Industrial 

 Research Committee than an investigation into the possil)ilities 

 of motor fuels from South African resources. 



The figures for indicated thermal efficiency given by Dugald 

 Clerk, who is recognised as the greatest authority on internal 

 combustion engines at the present day, ^h^wn in Table XI \'. 

 are of considerable interest. 



T.Al'.LE XTV. 



ludiislrial Thcniial lifficicucy of Steam and Infernal 

 Comhustwn Ruaiiics. 



Indicated efficicncv. 

 Steam. Percent. 

 Boulton and Watt, condensing low pres- 

 sure (about 1820 ) 3.8 



Cornish engine (about 1850) 9.0 



Triple expansion (about 1910) 17.0 



Parson's turbine ( aboiK T014) 23.0 



I Internal C<>iiihiistiou, 



Lenoir (about i860) 4.0 



Compression — Constant voIuuk^ (1X76').. l^^.o 

 (Two or four stroke) 



(1906) 35.0 



Com])ression — Constant Pressure (Die- 

 sel) (19T0) 40.0 



Fig. 40 gives a graphic representation of the heat con- 

 sumption per B.IT.P. hour of various prime movers. 



Efforts have been made to utilise the waste heat from 

 steam and interna! combustion emrjiie^. and a great deal nu)re 

 will probablv be done in the future, esoeciallv in connection 

 with the internal combustion (.'nijinc. rxhaust steam mifiht be 

 applied to a greater extent for heating nurposes ; its apv)lieation 

 in the exhaust steam turbine, introduced about m vears ayo. is 

 extending in cases where il is annlicable. Wrv little has been 

 done to utilise the hi'.di lemjierature exhaust gases from inter)ia1 



