ENG 
Enfranchisement, in law, the 
incorporating a person into any society or 
body politic ; such as the enfranchisement 
of one made a citizen of London or other 
city, or burgess of any town corporate, be- 
cause he is made partaker of its liberties, 
or franchises. 
ENGINE, in mechanics, is a compound 
machine, made of one or more mechanical 
powers, as levers, pullies, screws, &c. in 
order to raise, cast, or sustain any weight, 
or produce any effect which could not be 
easily effected otherwise. 
Engines are extremely numerous ; some 
used in war, as the battering-ram, ballista, 
waggons, chariots, &c. ; others ir^ trade 
and manufactures, as cranes, mills, presses, 
&c. ; others to measure time, as clocks, 
watches, &c. ; and others for the illustration 
of some branch of science, as the orrery, 
cometarium, and the like. 
In general we may observe, concerning 
engines, that they consist of one, two, or 
more of the simple powers variously com- 
bined together; that in most of them the 
axis in peritrochio, the lever, and the screw, 
are the constituted parts ; that in all a cer- 
tain power is applied to produce an effect 
of much greater moment ; and that the 
greatest effect or perfection is when it is 
set to work with four-ninths of that charge 
which is equivalent to the power, or will 
but just keep the machine in equilibrio. 
In all machines the power will just sus- 
tain the weight, when they are in the in- 
verse ratio of their distances from the cen- 
tre of motion. 
Engine, fire, by Rowntree. We have 
selected an engine by this maker to give a 
drawing and description, as it is greatly supe- 
rior to the common engine with two force 
pumps. As that kind of engine has so often 
been described by various authors, and its 
principle so easily comprehended from the 
description of a force-pump ; we judged it 
unnecessary to give any drawing of it. 
The fire engine, by Rowntree, is a dou- 
ble force-pump, of a peculiar construction, 
similar in its action to the . beer-engine 
(described under that article), but as it is 
on a much larger scale, its constructions are 
of course varied. Plate Rowntree’s Engine, 
fig. 1 and 2, are two elevations at right 
angles to each other, of the external part 
of the engine mounted on four wheels. Fig. 
3 and 4, are two sections perpendicular to 
each other, of the body of the engine or 
pump : fig. 5 and 6, are parts of the engine. 
The same letters are used as far as they 
ENG ' 
apply in all the figures, A, A, A, A ; fig. 3 
and 4, is a cast-iron cylinder truly bored, it is 
ten inches diameter and fifteen long; it has 
a flaneh at each end whereon to screw two 
covers, with stuffing boxes, a, a, in their 
centres, through which the spindle, B, B, 
of the engine passes, and being tight pack- 
ed with hemp round the collar, makes a 
tight joint ; the piston, D, is affixed to the 
spindle within the cylinder, and fits it tight 
all round by means of leathers, applied as 
described in the beer-engine ; at E, fig. 4, a 
partition called a saddle, is fixed in the 
cylinder, and fits against the back of the 
spindie tight by a leather. 
We have now a cylinder divided by the 
saddle, E, and piston, into two parts, whose 
capacity can be increased and diminished 
by moving the piston, with proper passages 
and valves to bring and convey away the 
■water : this will form a pump. These pas- 
sages are cast in one piece with the cylin- 
der : one, d, for bringing the water is square, 
and extends about |d round the cylinder ; it 
connects at bottom with a pipe, e ; at its 
two upper ends opens into two large cham- 
bers,/g, extending near the whole length 
of the cylinder, and closed by covers, h h, 
screwed on : i lc, are square openings (shewn 
by dotted squares in fig. 3.) in the cylinder, 
communicating with the chambers :fg, l m, 
are two valves, closing their ends of the curv- 
ed passage, d, and preventing any water re- 
turning down the passage, d : no, are two 
passages from the top of the cylinder to con- 
vey away the water ; they come out in the top 
of the cylinder, which, together with the top 
of the chambers, f,g, form a large flat surface, 
and are covered by two valves, p, q, to re- 
tain the water which has passed through 
them. A chamber, K, is screwed over 
these valves; and has the air-vessel, k, fig. 1 
and 2, screwed into its top; from each side 
of this chamber a pipe, w w, proceeds, to 
which a hose is screwed, as shewn in fig. l. 
Levers, xx, are fixed to the spindle at each 
end, as shewn in fig. l, and carry the han- 
dles, II H, by which men work the engine. 
When the piston moves, as shewn by the 
arrow in fig. 4, it produced a vacuum in 
chamber, /, and that part of the cylinder 
contiguous to it ; the water in the pipe, e, 
then opens the valve, m, and fills the cylin- 
der. The same motion forces the water 
contained in the other part of the cylinder 
through the valve, q, into chamber, K, and 
thence to the hose through the pipe, w; the 
piston being turned the other way, reverses 
the operation with respect to the valves, 
C 2 
