83 
in Bramah's Hydro-mechanical Press. 
it successively at 1,2, 8, &c. The shaded space ABD will be 
proportional to the effect of the pump worked by the crank D\ 
and the parallelograms 1, 2, 8, &c. shew the effect at the 1st, 2d, 
&c. strokes. The shaded space ACD is proportional to the effect 
of the pump w orked by the crank D ; and the effect of the 1st, 
2d, &c. strokes are shewn by the parallelograms J , 2, 8, &c. 
The mode of describing the figure is obvious, as the length of 
each stroke is equal to the vertical distance between its com- 
mencement and termination. The sum of the figures represent- 
ing water injected by each pump is very nearly equal to the pa- 
rallelogram AB CD ; the small spaces which are not shaded 
shew the parts wanting. 
If the shaded space ABD were turned so that the point B co- 
incided with the point C, and the line AB with the line DC, the 
figure would then shew the decrease of the quantity of water in- 
jected at each revolution ; or, in other words, the variation pro- 
duced in the power of the press by the use of the principle de- 
scribed in the patent. 
The case to which this improvement is at present applied, is 
one in which the advantages of the hydro-mechanical press are 
very considerable. It enables those who use it to conduct the 
same quantity of business with a less number of workmen ; there 
is less wear and tear of bags and wrappers ; the machinery oc- 
cupies less space ; and the destructive effect of the concussions 
of heavy stampers on buildings and machinery is avoided en- 
tirely : indeed so smooth and noiseless is the operation of one of 
these presses, that the business of expressing oil may be con- 
ducted anywhere, without disturbance to the neighbourhood. 
The application of the principle of the patent is not, however, 
confined to presses ; for the effect of any power which has pe- 
riodical variations of intensity may be made to produce a conti- 
nuous effect, proportional to the power by the application of this 
principle. One of the most obvious cases is that of tide-pumps ; 
and, if we recollect right, a considerable premium was offered 
for such a mode of working tide-pumps, by some of the societies 
for encouraging the arts, and in the Low Countries. 
VOL, XIV. NO. 27. JANUARY 1826. 
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