PERPETUAL MOTION OR THE HYDROSTATIC PARADOX. 
6a 
PENDULUM STEAM-ENGINE. 
Sir,— Encoura^-ed by the readiness which 
you show to give publicity to all designs and 
suggestions that have any claim to originality, 
or are at alt likely to be productive of practi- 
cal good, I take the liberty of sending you a 
sketch of a new form of a steam-engine, which 
may be termed a pendulum'-engine. 
1 made a model of an engine on this plan 
some years ago, and it answered very well ; 
however, I did not then give it publicity, be- 
cause 1 had hopes of being able to try its ac- 
tion on a larger scale; but, as an opportunity 
has not offered itself, I can only speak of it as 
a model. There are, no doubt, many defects 
in the plan ; and to any of your scientific cor- 
respondents, v?ho will do me the favour to 
point out such defects, and suggest any re- 
quired improvement, I shall feel much 
obliged. 
DESCRIPTION. 
A is the foundation ; B B the frame ; C C 
are two short cylinders, opposite to each 
other, into which swing the pistons at the end 
of the pendulum rod E, and to which is also 
affixed two catches, F F for opening and 
shutting the steam-cocks G G, by means of 
the -levers H H ; III are the steam-pipes; 
K is a guide-plate for the pendulum-rod. 
The action of the engine is represented by 
the dotted lines. As the piston vibrates into 
the cylinder, the short end of the catch passes 
over the lever, which is carried forward by 
the long end until the cock is opened ; when 
the action of the steam causing the piston to 
return, the short end acts upon the lever un- 
til the cock is closed : and so on alternately. 
The engine might be used for various pur- 
poses. Pumps could be connected by means 
of the cross-beam X, or a rotary motion com- 
municated to machinery by the crank Y and 
a fly-wheel. 
Should the engine be placed at a distance 
from the pumps, the cross-beam could be 
dispensed with, and a rod, Z, connected to 
the pendulum-rod, by which any length of 
stroke might be acquired by altering the point 
of connexion. 
Should high-pressure steam be an objec- 
tion, low-pressure could be employed by hav- 
ing two longer cylinders, the pistons being 
connected by one piston-rod, and the pendu- 
lum acting in the middle of it by means of a 
roller. 
I am, Sir, your obedient servant, 
Charles Slocke. 
Mechanic's Magazine, 
Old-Street, Mill-wall, Pplar, Feb, 12, 1835. 
USEFUL RESULT EXTRAORDINA» 
RY, OF THE USEFUL KNOWLEDGE 
SOCIETY’S LABOURS. 
Sir,— I perceive from a recent Number of 
the Mech. I\Iag., that an ingenious French- 
man is about to take out a patent for that 
long-sought desideratum, the perpetual mo- 
tion. Now, sir, as it happens that I have 
myself lately had the good fortune to achieve 
the discovery, you will, I hope, admit the 
propriety of allowing me to enter a caveat in 
your pages against any foreign rival’s preten- 
sions to priority — in case it should turn out, 
when he enrols his specification, that his me- 
thod is the same as my own. Thus much, 
Mr. Editor, is due, even out of bare justice 
towards the claims of native talent ! 
My invention (the details of which I will 
not trouble you with at present) is founded on 
the principle of the hydrostatic paradox, as 
that principle is laid down in the first number 
of the Library of Useful Knowledge, aii 
follows : — 
“We have seen how the displacing any 
portion of a fluid by a solid, whatever by the 
weight of the solid, produces no difference in 
the weight of the fluid, provided it stands at 
the same height as before ; and how raising 
the height of the fluid by plunging a solid into 
it, increases its weight. If the fluid is raised 
by pressing or forcing it upwards, in however 
thin a column, provided the vessel is kept 
full, and closed in all directions, the pressure 
of the fluid will be increased, and the weight 
of the vessel will he increased, although no- 
thing whatever, either solid or fluid, is added 
to it, or made to touch it. The cylindrical 
box e f (see fig. ) has a cube g fitted into its 
top, and there is a wire D fitted to a plate 
D, the size of the inside of the box, and 
moving up and down in it, water tight. The 
plate being at the bottom h i, water is poured 
into the box, so that it rises to e/, but does 
not rise in the tube. It is then balanced by 
a weight in the scale A. If the wire C is 
drawn up so as to raise the plate, and force 
