62 PRESIDENTIAL ADDRESS SECTION A. 



plants has been made, and the sini])hcity of working, the com- 

 pactness of the plant, and the wonderful economy of this 

 system, as compared with the extreme waste of fuel entailed 

 in nearly all the small-type steam engines (which suction gas 

 engines are qualified more practically to replace), account lor 

 the rapid advance made in the use of such plants in recent 

 years." 



The suction-producer may have an efficiency of over 85 per 

 cent., and a h.p. for an hour may l)c obtained for ih.e expendi- 

 ture of .8 to I lb. of coal. Ever since the con.miercial introduc- 

 tion of the suction gas producer using anihracite. coke or 

 charcoal, in 1903. efforts continued to be made with a view to 

 the utilisation of bituminous fuels. Dowson succeeded in 1008. 

 The use of liituminous fuel now ])rcsents no difficulties to the 

 makers of suction-gas jilants. and several such are now at work 

 in South Africa. 



Fig. 36 shows a plant of nearly Grx) b.h.ii.. installed at ihe 

 Machavie (iold Mines, using bituminous ':'oal, ba\ing a calorific 

 value of 10.900 b.th.u \^<^v lb. and containing (\o.j i)er cent, fixed 

 carbon, the consumption on full load being 1.146 lb. per b.h.p. 

 hour. 



Diesel Jiiigiiie- — An event of great importance in internal 

 combustion engineering was the introduction of the Diesel 

 engine first experimented in 189-'. bui not ])ublicly exhibited 

 until 1S98. It is now made in single units up to 6.000 h.])., and 

 even that is by no means the limit to its jjower. 



The result of tests show that 2,000 h.]). can l)e developed 

 in one cylinder. This opens pros])ects of Diesel engines of 

 20.000 h.j). It is anticipated that 3,000 li.]*. i)er cylinder can 

 be realised. 



;..-- ^^S- 37 ^fio^vs a Diesel engine of 120 b.h.p. of the four 

 cycle type supplied to Aliwal North Mmiici])ality, while a 4,000 

 h.p. two-cycle Diesel engine at work in llarlaiid and W'oolf's 

 shipyards at Belfast is shewn in Fig. 38. 



Its application to the propulsion of ^hii)> antl the wonderful 

 progress made in tliis direction has l/cen one of the most impor- 

 tant develcjpmenls of modern engineering. The Diesel engine 

 now provides the propelling force for shi])S of (i\-er 9,000 lon> 

 diMplacemenl, and the nndliple-eylinder !iigli-s])eed vertical 

 t\'pe, built in units U]) to 3.000 h.p.. willi 400 h.]). developed in 

 each cylinder, has made the modern submarine ])i)ssible. L'nfor- 

 ■tunatelv. the ^ui)i)ly of suitable fuel ha^ not kei)t ])ace with the 

 wonderful (kAeloi)ment of the nil engine, and there exists at 

 the present da\' C')nsid(>rable anxiet\- on that accotnit. 



The world's \ield of crude ])etroleiun was, in loM- <'d)out 

 ^7,000,000 tons. P>ui since :liis oil, apart from that distilled 

 from shale in ."-Scotland, has to su])])ly the world with ])etrol, 

 illnmiiiating oils and lubricants, less than half is available for 

 fnel oil, or for tT^e in Diesel engines. TTea\-y i)etroleum oil has 



