PUMP. 
fise 1 1 feet ; or if you will, let water be 
poured on the clack, to' the height of 1 1 feet, 
and refit the piston ; there will remain still 
nine feet of air between it and the water, 
which cannot be sufficiently rarefied by a 
foot stroke to open the clack, or fetch up 
more water : for in this case the air can only 
be rarefied in the proportion of 9 to 10 ; 
whereas, to make a bare equilibrium with the 
atmosphere, it ought to be as 9 to 1 3§ ; since, 
as 22 (or the complement of 11 to 33 feet of 
water, the weight of the whole atmosphere), is 
to 33 feet or the atmosphere, so is the inter- 
val spoken of, 9 to 13^; to complete which, 
the stroke ought to be at least 4§ feet long. 
However, by filling the whole void be- 
tween the piston and clack at first with water, 
this last objection might be removed. 
In some cases, the pump cannot be placed 
conveniently perpendicular to the well. For 
example: Being to raise water out of the well 
at A, by means of a pump at B (fig. 1 1), the 
best way will be to carry the barrel as low as 
the spring is, communicating therewith by 
means of the pipe at C. The bucket then 
playing in the barrel BC, will have the same 
effect as if the well was made perpendicular 
to the pump ; because the water, by its pro- 
per weight, will always replenish BC. 
And if it should happen, from some con- 
siderable impediment, that the barrel cannot 
get down to the well directly, it may he 
led about any other wav for convenience. 
And then making the pipe of conveyance, E, 
less in diameter than the barrel, it will sooner 
be exhausted of air, by moving the piston; 
and the water will follow very briskly, as by 
the leaden pump at B. 
It will, however, always be more easy to 
draw water with pipes that are large, and of 
an equal bore throughout, because the water 
will have a less velocity in them, and the f ic- 
tion will be in proportion less. Upon this 
i account, tne common pumps made by plumb- 
j ors, do not work so easy as those bored out 
of trees; because, by making the pipe that 
brings up water from the spring much less 
than the bucket, they, as it were, wiredraw 
the water raised. It the barrel, for instance, 
( is four inches in diameter, and the pipe of 
conduct one, it will in rising move sixteen 
| times as fast through the latter as it will 
through the former ; and at the expence of 
needless labour, as well as the great wear and 
friction of the machine. 
In practice, however, it is generally ob- 
served, that such leaden pumps as work 
pleasantly, and are light on the hand, have 
the water-way in the sucking- pipe nearly 
equal to one-fourth of the area 'ot the barrel ; 
and accordingly, an inch-and-a-half pipe will 
pretty well supply a three-inch barrel ; and 
a four-inch barrel should have a leading-pipe 
nearly two inches in diameter. 
In forcing-pumps, it is of the utmost con- 
sequence to avoid all contractions in the 
| pipes. The main which leads from the 
‘ forcing-pumps, should be equal to the work- 
| ing-barrel. If it is only half the diameter, 
; it has but one-fourth of* the area; the velo- 
I city in the main is four times greater than 
! that ot the piston ; and the force necessary 
for discharging the same quantity of water i's 
sixteen times greater. 
We shall, before we close the article on 
pumps, give an account of Mr. Boulton’s 
apparatus raising water. The principle for 
action of this machinery may be illustrated 
in the following manner: 
A horizontal pipe is formed of iron or any 
other substance sufficiently strong, expand- 
ing at one end like the mouth of a trumpet, 
and at the other furnished with a valve that 
may be opened or shut at pleasure ; near ibis 
smaller extremity is let. in a vertical pipe, at 
right angles to the horizontal one, furnished 
at thejuncture with a valve opening upwards, 
.and open at the other end. This machine 
is let down into a stream of water, so deep as 
to cover the horizontal pipe, the trumpet- 
like mouth of which is placed so as to meet 
the current: in this situation the valve being 
open, a current passes through the pipe, of 
equal velocity with the current of the 
stream ; if the valve is then suddenly closed, 
the recoil of the current will force open tiie 
valve ot the vertical pipe, through which will 
rush a column of water: the force. of the re- 
coil soon subsiding, ihe vertical column will 
press on the valve at its bottom, anti cause 
it to close the end of the vertical pipe, in 
which the ascending column of water will 
be detained. The horizontal valve being 
then opened, the current will recommence 
through the horizontal pipe, and upon closing 
the valve a recoil will happen as before, and 
an additional quantity of water will rise in the 
vertical pipe: by a repetition of the- above 
process, the water rising through the pipe 
will overflow into any vessel placed to receive 
tire water, forming a perpetual pump. The 
contrivances by which this instrument is 
made to draw water, from a depth below that 
of the impelling current, and to raise it to 
any height, will he mentioned hereafter. 
I he uses to which this engine may be ap- 
plied, are serious; besides the raising of 
water for the use of brewers, &c. it may be 
employed in raising water from the sea for 
salt-work, in draining marshes and pumping 
ships, and supplying with water those canals 
that are carried over or by the side of rivers. 
Bor the more clear description of this in- 
vention, it is proper to state its physical prin- 
ciple of action, as follows: 
First, when water moves or runs through a 
pipe, or close channel, or tube, if the end at 
which the water issues is suddenly stopped, 
the water will (by its acquired motion, mo- 
mentum, or impetus) act upon the sides or 
circn inference of the pipe; which being sup- 
posed strong enough to resist that impetus, 
the water will issue, with violence or ve- 
locity, at any aperture which may exist in 
or near the shut end of the pipe; and if to 
that aperture an ascending pipe is joined, a 
portion of water will rise in it. 
Secondly, if a pipe, open at both ends, 
with an ascending pipe, such as has been de- 
scribed, is moved along, through standing 
water, in the direction of its length ; upon 
shutting the hinder part of the pipe, a por- 
tion ot the water will rise in the ascending- 
pipe, in the manner which has been stated 
in the former case, because the water is rela- 
tively in motion in respect to the pipe. 
Thirdly, if in either of the < ases recited, a 
pipe communicating with water at any lower 
ievel is joined to the main pipe, at or near 
the end at which water enters into it; and if, 
when such water has acquired motion rela- 
tively to that pipe (bv the pipe being put in 
3 U 2 
528 
motion), the mouth or end at which the water 
enters is suddenly shut; the water, continuing 
its motion relatively to the pipe, will draw or 
suck up water from the lower level, through 
the ascending pipe, in order to 'fill up the 
vacuity occasioned by the water in the main 
pipes, persevering in its. previous motion, 
u hat has been said respecting water, is also 
true hi respect to other fluids. 
I he several cases above stated are resolv- 
able into the general principle of the resist- 
ance which water and other fluids (and in 
general all bodies) make to a. change of their 
state of rest, or motion, whether absolute or 
lelative ; and this principle has heretofore 
been applied to the raising of water only 
in a comparatively small and weak degree, 
and in a defective manner. But the improved 
apparatus continues its own action when 
once set going, unless some accident should 
stop or derange it ; and is capable of 
raising water in great quantities, and to great 
heights, and they also differ, in other respects, 
iro.n any thing which has been executed hi- 
therto. 
i he nature of the said improved invention 
consists m using valves, of various construc- 
tions, instead ot cocks, to open or shut the 
end, or ends, of a main pipe : and in the ap- 
plication of mechanism, or contrivances to 
assist in opening and shutting the valves at 
proper times ; whereby water is raised in- 
dependantly of any other power than a cur- 
rent of water through the main pipe. 
1 he manner in which 'the said invention 
is to be performed, and the said improved 
apparatus and methods carried into effect, 
is as follows, viz. : 
I lie first and most simple method is shewn 
in fig. 12, in which CC is the main pipe ; 
DD the ascending pipe ; A the valve of exit 
for the water to be raised ; B the stop-valve ; 
and E a weight which, by the lever F, at- 
tached to the axis G of the stop-valve B, opens 
it at the proper time. The said apparatus 
acts in the following manner: The main pipe 
being situated or fixed in a current or stream 
oi water, either produced by the natural cur- 
rent or declivity of the river or other stream; 
or (which is preferable) by penning up water 
by a dam, weir, or bank, and by inserting 
the end of the main pipe through the said 
clam, weir, or bank, so as to obtain the 
greatest head or current of w'ater the natural 
circumstances admit of ; the stop-valve b< iua- 
opened to the position shewn in the figures, 
the water will run through the main pipe, 
until, by its action upon the stop-valve in 
its reclined position, it raises the weight, 
shuts the stop-valve, and the water, Ln v ° its 
impetus or momentum, opens the exit-valve 
and a portion of it rises in the ascending 
pipe ; after which, the last-mentioned valve 
shuts, the water in the main pipe recoils, the 
weight descends and opens the stop-valves, 
and the water in the main-pipe regains 
its velocity. The like operations are re- 
peated, and the water gradually rises in the 
ascending pipe, until it reaches its summit, 
and a quantity issues thence every stroke- 
which quantity is. more or less, according as 
the height to which it is raised is less or 
greater. 
J is an air-vessel, or reservoir of air, where- 
by the bursting of the pipes is prevented, or 
the danger thereof much diminished. Lit® 
