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154 
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THE TRIALS OF SUCTION GAS PLANTS 
AT DERBY, 1906. 1 
r 7 ( Capt. H. Riall Sankey, R.E. (ret.), M. Inst. C.E. 
judges^ prof< w E DalbY; m>a<j b.Sc., M. Inst. C.E. 
The combination known as a suction gas plant, in which 
a gas engine provides, by means of its suction stroke, the draft 
necessary to make the fuel burn in a producer, is of very recent 
origin. As regards the Royal Agricultural Society, the first 
exhibit was made in 1901 at Cardiff by Messrs. Crossley Bros., 
Ltd. Then at the 1903 Show at Park Royal a suction gas 
plant was exhibited by the Dowson Economic Gas and Power 
Company, Ltd., which was a combination of a Dowson producer 
with a National gas engine. Messrs. Crossley Bros., Ltd., also 
exhibited a suction gas plant at this Show. At the 1904 Show 
three such plants were entered, and at the 1905 Show the 
number had increased to four. 
This increase in exhibits of suction gas plants, together 
with the claims set forth by the makers in respect of the 
reliability and economy of such plants, was mainly responsible 
for the decision to hold the trials now being reported on. 
The response of the makers was beyond expectation. Fourteen 
plants were entered for trial and many others were exhibited. 
All the fourteen plants started on Monday morning, June 18, 
but three of them were withdrawn during the trials. The list 
of the competing plants is given in the Table on page 155. 
Object of the Trials. 
Regarded from the point of view of the Royal Agricultural 
Society, the object of these trials was to determine, so far as 
a series of trials extending over one week would permit, 
whether suction gas plants could be relied on to work for 
agricultural purposes, day in and day out, with the same 
degree of freedom from breakdowns as a steam engine, and 
with the same small amount of attendance as is required by 
an oil engine. Satisfactory answers to these questions would 
prove the suitability of such plants for agricultural purposes, 
because there is no doubt as to the great improvement in fuel 
economy, as compared with either a steam or an oil engine of 
the same power. 
One of the most important factors in judging the merits 
of the various plants was the fact that these combinations of 
1 Abridged from the Official Report on the Trials. 8vo., 56 pp., 25 illus- 
trations, price Is. John Murray, London, 1906. Copies of the complete 
Report are obtainable through any bookseller, or by Members direct from the 
Society. 
