Miscellaneous Implements Exhibited at Bristol , 1913. 265 
Messrs. Blackstone have fitted to an oil engine a modification 
of the Humphrey’s gas pump for circulating the water, which 
is very simple. The circulating water is cooled by passing 
over a cone of perforated metal, and then falls into a small 
tank some 15 in. deep, of somewhat larger diameter than the 
base of the cone. Along side of this is fixed the barrel of the 
pump, a plain vertical piece of pipe about 2 in. diameter, the top 
communicating by a tube with the exhaust pipe, the bottom on 
one side opening with a non-return valve into the tank, and on 
the other with a delivery valve to the rising main to the top of 
the cooling cone. It will be seen that the water from the tank 
will find its own level in the vertical pipe say to 12 in. for 
example ; when the exhaust valve opens there is a temporary 
rise of pressure in the vertical pipe and part of the water is 
forced up the rising main past the delivery valve ; on the suction 
stroke of the engine there being no pressure in the vertical 
pipe water again rises to the level of that in the tank. It will 
be noticed that the greater the number of explosions or the 
greater their force, the more water is delivered, which is as it 
should be. 
There were of course many exhibits which cannot be said 
to bear directly on agriculture but still are of interest to the 
engineer. Such a one is the Suction Gas Plant shown by 
Messrs. Crossley. The engines of this firm may be said to 
embody all the latest improvements, such as ring oiling for the 
bearings, and in the larger sizes very efficient governing by 
variable admission of gas and air. As regards the gas producer 
the grate is open to the atmosphere and in full view of the 
attendant, being formed of three discs of plate one under the 
other, the hole in the lower one being smaller than that in 
the one above. The column of fuel thus rests on a bed of ash 
and can easily be clinkered. There is no water jacket to the 
producer proper, the gases from which come off hot and 
surround the boiler which is made of tubes with gills cast on, 
the steam being taken by a pipe and delivered close to the 
ashes lying on the grate plates, so that it is drawn into the fire 
on the suction stroke of the engine. The boiler thus helps to 
cool the gas as well as to raise steam. After leaving the boiler 
flue, so to speak, the gas meets two cascades of water coming 
from the scrubber, before ever it comes in contact with the 
wet coke. The fan for blowing up the fire is of course on the 
engine side of the producer, and is a suction instead of a 
pressure fan. 
There has hitherto been a difficulty in using bituminous 
coal in suction gas plants, due to the formation of tar. 
Messrs. Kynoch, Stand 328, show a Bituminous Suction 
Gas Plant of a somewhat novel construction. Broadly speaking 
