184 The Trials of Suction Gas Plants at Derby , 1906. 
attendance, it is less than would be necessary for a steam 
engine and boiler, and not sensibly greater than what is needed 
by an oil engine of the same power under like circumstances. 
It may be said that, as regards reliability, the duration of 
the trials was insufficient to warrant a definite opinion ; and 
undoubtedly only actual experience can show to what extent 
“ clinkering ” and “ staging ” of the fuel may be sources 
of trouble in the conditions under which suction gas plants 
may have to run for agricultural purposes. It is interest- 
ing to note in this connection that the Dowson producer, 
working in conjunction with the Railway and General 
Engineering Company’s engine, had been in use continuously 
for three months prior to the trials, and it was found, on close 
examination, that the condition of the furnace was quite satis- 
factory, and the amount of clinker firmly adhering to the 
firebrick lining was very little. It is generally supposed that 
the firebrick lining in a well-designed producer, that is, one 
in which the steam supply is properly regulated, ought to last 
about two years. The expense of replacing the firebrick at such 
intervals cannot be regarded as a serious item of expense. 
It is probable that suction gas plants will be able to replace 
portable steam engines for many purposes with distinct advan- 
tages both as regards handiness and economy. 
A further step in advance will be made when a traction 
suction gas plant has been placed on the market. Another 
desideratum is a suction producer which will deal satisfactorily 
with bituminous coal. It is understood that several firms are 
experimenting with such plants, that successful results have 
been obtained already, and that at no distant date it may be 
possible to hold competitive trials. 
In conclusion, the Judges desire to express their approval of 
the arrangements made by the Consulting Engineer of the 
Society and his Staff for carrying out the trials. They also 
fully appreciate the readiness with which the exhibitors gave 
them information. 
H. Riall Sankey. 
25 Victoria Street, 
Westminster, S.W. 
