168 The Trials of Suction Gas Plants at Derby , 1906. 
is of the marine type at both ends and is a very substantial 
piece of work. The lubrication of the main bearings is effected 
by means of rings and that of the big end by means of the 
usual centrifugal pipe. The piston is lubricated by a drip sight 
feed and there are special grooves on the piston to prevent the 
oil being blown away in the event of the piston rings leaking. 
The governing is of the usual hit-and-miss type. 
The Grossley engine . — This engine is shown in Fig. 5, page 
166, and is very similar in design to the National engine. The 
arrangement of the magneto is somewhat different, but is 
equally simple. The spark can be retarded by a definite amount 
for starting. The connecting rod is of the marine type at the 
big end and of the locomotive type at the small end. 
Description of the Trials. 
* 
The trials were started at 9 a.m., on Monday, June 18, and 
began with the full load trials using anthracite as a fuel. The 
producers were empty and the time of starting each engine 
and of getting on the full load, from the moment of laying the 
fire, was noted. The various plants were started at intervals, 
and each was run for nine hours on full load and then stopped. 
The hopper and the fire doors of every producer were then 
sealed up. The last engine was stopped at about 7 p.m. During 
the night the fires were banked, and on : 
Tuesday , June 19, at 9 a.m., the first plant started on 
Monday was got under way and the time required before the 
engine could be started and the full load put on was noted. 
The other plants were successively started in the same manner, 
so that in each case the fires were banked for approximately 
fourteen hours. The full load was maintained for five hours, 
after which the engines were stopped, the fires drawn, and 
the partially consumed fuel placed in iron vessels for weighing 
and examination. 
This completed the full load anthracite trials which con- 
sisted of nine hours full load, fourteen hours banked fires, and 
five hours full load. 
Wednesday , June 20. — The half load anthracite trial was 
carried out this day ; the starting of the plants from laying 
the fire was a repetition of the trials carried out on Monday. 
Each engine ran for nine hours on half load when the engine 
was stopped, the fire draAvn, and the fuel placed in iron vessels 
for weighing and examination as before. 
Thursday , June 21. — The variable load trial was made 
on this day ; the first plant was started at 9 a.m., and the others 
were started in succession at short intervals. Each engine was 
run for two hours with no load from the time of starting. 
Then full load was quickly put on and maintained for one 
