Discussion of the Regulations. 
157 
Before proceeding to a description of the plants and of the 
trials carried out it is desirable to make a few remarks on these 
regulations, in order to indicate the general considerations 
which guided the Judges in the inquiries and observations 
they made during the trials, and in making the award. 
In the first place it is to be borne in mind that it was the 
combination of producer and gas engine that was being judged, 
the former, however, owing to its comparative novelty, requir- 
ing most attention and criticism. It may also be pointed out 
that with two exceptions the engines themselves were of the 
usual horizontal type, and embodied the results of the long 
experience of the various makers. 
1. Attendance necessary. — An important distinction must 
be drawn between the attendance required for starting the 
plant and that needed for looking after it when running, 
that is, for attending to the lubrication and for filling the hopper 
with coal. Should additional help be needed at starting for 
turning the flywheel, little or no additional expense is incurred. 
During running only one attendant is needed at most, and, 
if the plant is quite reliable, it can in many cases be left to 
itself for comparatively long periods, and the attendant can 
perform other duties during such periods. The attendance 
required during running is thus in a measure dependent on the 
regularity of the working or reliability of the plant. Some 
of the engines were fitted with self-starters (see Table on 
page 155), and it is clear that, with engines of the size under 
trial, the only gain is to save the small expense above referred 
to for starting, whereas extra complication and chances of 
failure are introduced by the starting apparatus itself. 
2. General design , including facility of cleaning , and space 
occupied. — A simple straightforward design is the desideratum. 
Since the main lines of the design of the gas engines were, 
except in two instances, common to all, the details were the 
points which had to be most carefully considered. As regards 
the producers they followed closely the lines of the “ Dowson ” 
producer, and therefore differences were investigated ; they 
were principally confined to arrangements which aimed at re- 
ducing the difficulties caused by clinker, to means of regulating 
the air and water supply and for increasing the regenerative 
effect of the suction producer. Hard water may cause trouble 
by “ scaling,” and this is a matter of great importance ; but 
the relative immunity of the various producers in this respect 
could not be tested in the short time available, and there- 
fore could only be gauged by general considerations. The 
design of the plant in respect of provision against possible 
escape of poisonous gas or risk of explosion required careful 
consideration. 
