SO Mr TredgolcTs Description of an Improvement 
greatest pressure. Hence, in such a case as expressing oil from 
seeds, where the resistance in the first part of the operation is 
small, and increases till the compression is considered to be suf- 
ficient, the machinery must be adapted for working the pumps 
when at the maximum pressure, and, consequently, there must 
be a great excess of power in every other part of the operation. 
In any hydro-mechanical press the power is proportional to 
the quantity of water injected, at a stroke of the pump, mul- 
tiplied into the resistance; therefore, when the resistance is small, 
the quantity of water injected at a stroke should be increased, 
in order that the power necessary to work the press may be as 
uniform as possible, and this is the object of the patent we are 
about to describe *. 
The machinery is applied to an oil-press (See Plate II. fig. 1.), 
of which M is the press-cylinder, and NN' the bags containing 
the seeds ; one part of the drawing shewing the exterior, and the 
other a section of the press boxes which contain the seed bags. 
LL' are the tubes which convey the water injected by the 
pumps to the press-cylinder M. 
I is the cistern for supplying the pumps with water, and it 
supports the pumps and the machinery for working them by 
means of the pillars HH'. 
The power which works the pumps is applied to the shaft E', 
and is regulated by a fly-wheel ; and the motion is communi- 
cated to the other shaft E by the toothed wheels F'F. The 
two pump-pistons CC' are worked by the cranks DD', on the 
ends of the shafts EE 7 ; and the cranks are made to adjust by 
set screws, so as to limit the length of the stroke to any requir- 
ed quantity within the limits of their action. The cranks act 
on the pump-pistons by connecting rods and slings in the usual 
manner. 
The pump-cylinders AA' are connected by the copper tube 
BIT, which is again connected to the junction-piece K by a sin- 
gle tube. The junction-piece K contains the stop, forcing, and 
discharge valves, and is connected to the tubes LL', which con- 
vey the water injected by the pumps to the press-cylinder. 
* The discovery of this improved method of working the press, was made by 
Mr Spiller, and for which a patent was lately obtained by him in conjunction with 
Messrs Bramah. 
