This engine was placed upon a barge on 
the water, and so was easily conveyed to any 
place desired. The nun was a ton weight; 
and the guides bb, by which it was let fall, 
were 30 feet high. 
Description of Ranee's pile- engine.. — Figs. 
5 and 6 represent a side and front section of 
the machine. The chief parts are, A B fig. 5. 
which are two endless ropes or chains, con- 
nected by cross pieces of iron, B (lig. 0.), 
j corresponding with two cross grooves cut 
diametrically opposite in the wheel C (iig. 5 ), 
into which they are received, and by which 
means the rope or chain A is carried round. 
D is a wheel, over which the chain passes 
and turns within at the top of the frame. 
It moves occasionally from F to G upon 
the centre II, and is kept in the position F 
■ by the weight I fixed to the end K. In 
I fig. 7, L is the iron ram, which is connected 
[ with the cross pieces by the hook M. N 
> is a cylindrical piece of wood suspended 
i at the hook at O, which, by sliding freely 
| up the bar that connects the hook to the 
j ram, always brings the hook upright upon the 
I chain when at the bottom of the machine. 
When the man at S turns the usual crane- 
work, the ram, being connected to the chain 
? and passing between the guid s, is drawn up 
in a perpendicular direction ; and when it is 
near the top of the machine, the projecting 
[ bar Q of the hook strikes against a cross 
\ piece ot wood at R (fig. 5.), and consequent- 
[ ly discharges the ram; while the weight T of 
, the moveable frame instantly draws the up- 
per wheel into the position shewn at F, and 
| keeps the chain free of the rani in its descent. 
I The hook, while de cending, is prevented 
| from catching the chain by the wooden piece 
\ N : for that piece being specifically lighter 
: than the iron weight below, and moving with 
1 a less degree of Velocity, cannot come into 
| contact with the iron till it is at the bottom 
I and the ram stops. It then falls, and again 
I connects the hook with the chain, which 
( draws up the ram as before. 
In this machine, as well as Vauloue’s, the 
motion of the first wheel is uninterrupted, so 
that very little time is lost in the operation : 
with a slight alteration it might be made to 
work with horses. It has the advantage over 
Vauloue’s engine in point of simplicity: it 
may be originally constructed at less expence, 
and is not so liable to be deranged. Both, 
however, are ingenious performances, and 
| part of their construction might be advan- 
| tageously introduced into other machines. 
Engines for raising water by the pressure 
and descent of a column inclosed in a pipe, 
have been lately erected in different parts of 
this country. The principle now adverted to 
was adopted in some machinery executed in 
France about 1731, and was likewise adopted 
in Cornwall more than forty years ago. But 
the pressure-engine of which we are about to 
give a particular description, is the invention 
of Mr. R. Trevithick, who probably was not 
aware that any thing at all similar had been 
attempted before. "This engine, a section of 
which, on a scale of a quarter of an inch to 
afoot, is shewn in Plate Engines, fig. 8, was 
erected about eight years ago at the Druid 
copper-mine, in the parish of Illogan, near 
Truro. AB represents a pipe six inches in 
diameter, through which water descends 
from the head to the place of its delivery to 
ENGINES, 
run off by an adit at S, through a fall of 34 
fathom in the whole ; that is to say, in a close 
E down the slope of a hill 200 fathoms 
with 2G fathoms fall ; then perpendicu- 
larly six fathoms, till it arrives at B ; and 
thence through the engine from B to S two 
fathoms. At the turn i> the water enters 
info a chamber C, the lower part of which 
terminates in two brass cylinders four inches 
in diameter ; in which two plugs or pistons of 
lead, D and E, are capable ot moving up and 
down by their piston rods, which pass through 
a close packing above, and are attached to 
the extremities of a chain leading over and 
properly attached to the wheel Q, so that it 
cannot slip. 
The leaden pieces D and E are cast in 
their places, and have no packing whatever. 
They move very easily ; and if at any time 
they should become" loose, they may be 
spread out by a few blows with a proper in- 
strument, without Inking them out of their 
place. On the sides of the two brass cylin- 
ders, in which D and E move, there are 
square holes communicating towards G, 
which is an horizontal trunk or square pipe, 
four inches wide, and three inches deep. 
All the other pipes G, G, and R, are six in- 
ches in diameter, except the principal cylin- 
der wherein the piston H moves; and this 
cylinder is ten inches in diameter, and admits 
a nine-foot stroke, though it is here delineated 
as if the stroke were only three-foot. 
1 lie piston-rod works through a stuffing- 
box above, and is attached to MN, which is 
the pit-rod, or a perpendicular piece divided 
into two, so as to allow its alternate motion 
up and down, and leave a space between, 
without touching the fixed apparatus or great 
cylinder. The pit-rod is prolonged down 
into the mine, where it is employed to work 
the pumps ; or if the engine was applied to 
mill-workj or any other use, this rod would 
be the communication of the first mover. 
KL is a tumbler or tumbling-bob, capable 
N Qf being moved on the gudgeons V, from its 
present position to another, in which the 
weight L shall hang over with the same in- 
clination on tiie opposite side of the perpen- 
dicular, and consequently the end K will then 
be as much elevated as it is now depressed. 
r l iie pipe RS has its lower end immersed 
in a cistern, by which means it delivers its 
water without the possibility of the external 
air introducing itself ; so that it constitutes a 
Torricellian column or water-barometer, and 
renders the whole column from A to S effec- 
tual, as we shall see in our view of the ope- 
ration. 
The operation . — Let us suppose the lower 
liar KV of the tumbler to be horizontal, and 
the rod PO so situated as that the plugs or 
leaden pistons D and E shall lie opposite to 
each otiier, and stop the water-ways G and 
F. In this state of the engine, though each 
of these pistons is pressed by a force equiva- 
lent to more than a thousand pounds, they 
will remain motionless, because these actions 
being contrary to each other, they are con- 
stantly in equilibrio. The great piston H 
being here shewn as at the bottom of its cy- 
linder, the tumbler is to be thrown t>y hand 
into the position here delineated. Its* action 
upon OP, and consequently upon the wheel 
Q, draws up the plug D, and depresses E, so 
that tlfo water-way G becomes open from 
623 
AB, and that of F (o the pipe R : the water 
consequently descends from A to C, thence 
to GGG, until it acts beneath the piston PI. 
I his pressure raises the piston ; and if there 
be any water above the piston, it causes it 
to rise and pass through F into R". During 
the rise of the piston (which carries the pit- 
rod MN along with it), a sliding block of 
wood I, fixed to this rod, is brought into 
contact with the tail Iv of the tumbler, and 
raises it to the horizontal position, beyond 
which it oversets by the acquired motion of 
the weight L. 
The mere rise of the piston, if there was 
■ no additional motion in the tumbler, would 
only bring the two plugs I) and E to the po- 
sition of rest, namely to close G and F, and 
then the engine would stop ; but the fall of 
the tumbler carries the plug I) downwards 
quite clear of the hole F, and the other plug 
E upwards quite clear ol the hole G. These 
motions require no consumption of power, 
because the plugs are in equilibrio, as was 
■just observed. 
In this new situation the column AB no 
longer communicates with G, but acts through 
F upon the upper part of the piston PI, and 
depresses it; while the contents of the great 
cylinder beneath that piston are driven out 
through GGG, and pass through the opening 
at E into R. It may be observed, that the 
column which acts against the piston is as- 
sisted by the pressure of the atmosphere, 
rendered active by the column of water 
hanging in R, to which that assisting pres- 
sure is equivalent, as has already been no- 
ticed. 
When the piston has descended through a 
certain length, the slide or block at T, upon 
the pit-rod, applies against the tail K of the 
tumbler, which it depresses, and again over- 
sets ; producing once more the position of 
the plugs DE, here delineated, and the con- 
sequent ascent of the great piston H, as be- 
fore described. The ascent produces its for- 
mer effect on the tumbler and plugs ; and in 
this maimer it is evident that the alternations, • 
will go on without limit, or until the manager 
shall think fit to place the tumbler and plugs 
DE in the positions of rest, namely, so as to . 
stop the passages FandG. 
The length of the stroke may be varied by- 
altering the positions of the pieces T and I,, 
which will shorten the stroke the nearer they 
are together; as in that ease they will sooner 
alternate upon the tail K. 
As the sudden stoppage of the descent of 
the column AB, at the instant when the two 
plugs were both in the water-way, might jar 
and shake the apparatus, those plugs are made 
half an inch shorter than the depth of the side 
holes, so that in that case the water can 
escape directly through both the small cylin- 
ders to R. This gives a moment of time for 
the generation of the contrary motion in the 
piston and the water in GG'G, and greatly 
deadens the concussion which might else be 
produced. 
Some former attempts to make pressure- 
engines upon the principle of the steam-en- 
gine have failed; because water,. not being 
elastic, could not be made to carry the pis- 
ton onwards a little, so as completely to shut 
one set of valves and open another. In the 
present judicious construction, the tumbler 
performs the office of the expansive force of 
steam at the end of the stroke. 
