Thomas Ewbank.

A descriptive and historical account of hydraulic and other machines for ... online

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cations that have the advantage of a small fall. The distance between
the vessels not exceeding the perpendicular descent of the motive column,
which last is made to transmit its force to each vessel in succession — forc-
ing the contents of one into the next above, and so on. Such a machine
is interesting as showing the extent to which the principle of Heron's
fountain may be applied, but for practical purposes it is of little value. It
is too complex (if made self-acting) and too expensive for common use ;
and it is far inferior to the water ram. It was described by Dr. Darwin,
in his Phytologia, to which modern writers generally refer, but it is an
old affair. It is figured by Moxon in his "Mechanick Powers," Lon. 1696,
and is mentioned by older authors. It is substantially the same as the
double fountain of Heron, as found in the Spiritalia and the works of most
writers on hydraulics.

By far the most novel and interesting modification of Heron's fountain
was devised in the year 1746 by H, A, Wtrlz, a Swiss pewterer or tin-
plate worker of Zurich. It is sometimes named a spiral pump, and waa
made to raise water for a dye house in the vicinity oi that city. What the
circumstances were that led Wirtz to its invention we are not informed—
whether it was suggested by some incident, or was the result of reasoning
alone. It is represented in the illustrations Nos. 165 and 166, the first
jeing a section and the latter an external view.

No.169l Section of Wirto'i PUMP. NalM. Vtewof WirU'< Pump.

Wirtz's machine consiifts either of a helical or a spiral pipe. As the
former it is coiled round in one plane asABCDEFin No. 165. As
a spiral it is arranged round the circumference of a cone or cylinder, and
tr en resembles the worm of a still. The interior end at G is united by a
water tight joint to the ascending pipe H. See No. 166. The open end


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364 Wiriz's Pump. [Book IJI.

of the coil is enlarged so as to form a scoop. When the machine, im-
mersed in water as represented, is turned in the direction of the arrow,
the water in the scoop, as the latter emerges, passes along the pipe driv-
ing the air before it into G H, where it escapes. At the next revolutioi:
both air and water enter the scoop ; the water is driven along the tube as
before, but is separated from the first portion by a column of air of nearly
equal length. By continuing the motion of the machine another portion
of water and another of air will be introduced. The body of water m each
coil will have both its ends horizontal, and the included air will be of
al>out its natural density ; but as the diameters of the coils diminish to-
wards the centre, the column of water which occupied a semicircle in the
oater coil, will occupy more ahd more of the inner ones as they approach
the centre G, till there will be a certain coil, of which it will occupy a
cosLolete turn. Hence it will occupy more than the entire space w^ithin
this coil, and consequently the water will run back over the top of the
succeeding coil, into the right hand side of the next one and push the
water within it backwards and raise the other end. As soon as the water
"ises in the pipe G H, the escape of air is prevented when the scoop
takes in its next quantity of water. Here, then, are two columns of water
acting against each other by hydrostatic pressure, and the intervening co-
jumn of air. ^hey must compress the air between them, and the water
and air columns will now be unequal. This will have a general tendency
io keep the whole Water back and cause it to be higher on the left or ris-
jig sid!e of each coil, than on the other. The excess of height will be just
uch as produces the compression of the air between that and the preced-
ng column of water. This will go on increasing as the water mounts in
H. Now at whatever height the water in H may be, it is evident that
the air in the small column next to it will always be compressed with the
weight of the water in H — an equal force must therefore be exerted by
the water in the coils to support tiie column in H. This force is the sum
of all the differences between the elevation of the inner ends of the water
in each coil above the outer ends ; and the height to which"" the water will
rise in H will be just equal to this sum. Dr. Gregory observes that the
principles on which the theory of this machine depends are confessedly
mtricate ; but when judiciously constructed, it is very powerful and effec-
tive in its operation. It has not been ascertained whether the helical or
spiral form is best. Some of these machines were erected in Florence in
1778. In 1784, one was made at Archangelsky, that raised a hogshead oi
water in a minute to an elevation of seventy-four feet, and through a pipe
seven hundred and sixty feet long. See Gregory's Mechanics, vol. ii.

It perhaps may facilitate an understanding of this curious machine, by
remarking that the pressure exerted by tiie column of water in one side of
each coil is proportioned to its length, and that this pressure is transmit-
ted, through the column of air between them, to that of the next: the com-
bined force of both is then made to act, by the revolution of the tubes
upon the third column, and so on, till tiie accumulated force of Uiem al.
is communicated to the water in H ; and hence the elevation to whicl
water can be thus raised, can never exceed the sum of the altitudes of the
liquid columns in the coils.



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DsTicci of tke lower uhmb - 8omo aaiiMli aware that Ibroe fe iaereaaeil by tke epMe thteufb
whiek a body noree— Birdi drap ehell (Uh. Aran great eleratioaa to break tbt thtHe Death of JBiehjlw
— Coeibata between tbe malet of eheep and gnete MiHtwy ram of the aaciente— Water nnie*-Wai*ee
— -Mameatttin acquired by mnninf watei^— Bxamplee— Whltehuret'a nuchine— Hydnullc ram of llonC-
foUei^-** Canne hydranUque'* and ita Modificatione.

Of the machines appropriated to the fourth division of this work, (see
page 8,) centrifugal pumps and a few others have already been descrfoea.
There remain to be noticed, the water ram, canne hydraulique, and ae-
vices for raising water by means of steam and other elastic fluids.

If the various operations of the lower animals were investigated, a thon-
sand devices that are practised by man would be met with, and probably
a thousand more of which we yet know nothing. Even the means by which
they defend themselves and secure their food or their prey, are calculated
to impart useful information. Some live by stratagem, laying concealed
till their unsuspecting victims approach widiin reach - H>thers dig pitfalls
to entrap them ; and others again fabricate nets to entangle them» and
coat the threads with a glutinous substance resembling the birdlime of the
fowler. Some species distill poison and slay their victims by infusing it
into their blood ; while others, relying on their muscular ener^, suffocate
their prey in their embraces and crush both body and bones into a pulpy
mass. The tortoise draws himself into his shell as into a fortress and bicfs
defiance to his foes; and the porcupine erects around his body an array of
bayonets from which his enemies retire ^vith dread. The streng^th of the
ox, the buffalo and rhinoceros is in their necks« and which Uiey appjv
with resistless force to gore and toss their enemies. The elephant by nis
weight treads his foes to death ; and the horse by a kick inflicls a wound
that is often as fatal as the bullet of a riAe ; the space through which his
foot passes, adding force to the blow. •

There are numerous proofs of some of the lower animals being aware
'Jiat the momentum of a moving body is increased by the space through
which it falls. Of several species of birds which feed on shell fish, some,
when unable to crush the shells with their bills, carry them up in the
air, and let them drop that they may be broken by the fall. (The Athe-
nian poet £schylus, it is said, was killed by a tortoise that an eagle drop-
ped upon his bald head^ which the bird» it is supposed, mistook for a stone.)


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S66 Momentum of Running Water. [Book IV

When the males of sheep or goats prepare to hutt, they always recede
backwards to some distance ; and then rushing impetuously forward, (ac-
cumulating force as they go,) bring their foreheads in contact with a shock
that sometimes proves fatal to both. The ancients, perhaps, from witness
ing the battles of these animals, constructed military engines to act on the
same principle. A ponderous beam was suspended at the middle by chains,
and one end impelled, by the united efforts of a number of men at the op-
posite end, against walls which it demolished with slow but sure effect.
The battering end was g;enerally, and with the Greeks and Romans uni-
formly, protected by an iron or bronze cap in the form of a ram*s head ;
and the entire instrument was named after that animal. It was the most
destructive of all their war machinery — no building, however solid, could
long withstand its attacks. Plutarch, in his life of Anthony, mentions one
eighlyfeet in length.

The action of the ram is familiar to most people, but it may not be
known to all that similar results mi^ht be produced by a liquid as by a solid
— that a long column of water moving with great velocity might be made
equally destructive as a beam of wood or iron — yet so it is. W aves of the
sea act as water-rams against rocks or other barriers that impede their
progress, and when their force is increased by storms of wind, the most
solid structures give way before them. The old lighthouse on the Eddy-
stone rocks was thus battered down during a storm in 1703, when the
engineer, Mr. Winstanley, and all his people, perished.

The increased force that water acquires when its motion is accelerated,
might be shown by a thousand examples : a bank or trough that easily
retains it when at rest, or when slightly moved, is often insufficient when
its velocity is greatly increased. When the deep lock of a canal is opened
to transfer a bdat or a ship to a lower level, the water is permitted to de-
scend by slow degprees : were the gates opened at once, die rushing mass
would sweep the gates below before it, or the greater portion would be
carried in the surge quite over them — and perhaps the vessel also. A
sluggish stream drops almost perpendicularly over a precipice, but the mo-
mentum of a rapid one shoots it over, and leaves, as at Niagara, a wide
space between. It is the same with a stream issuing from a horizontal
tube — if the liquid pass slowly through, it falls inertly at the orifice, but
if its velocity be considerable, the jet is carried to a distance ere it touches
the ground. The level of a great part of Holland is below the surface of
the sea, and the dykes are in some parts thirty feet high : whenever a
leak occurs, the greatest efforts are made to repair it immediately, and for
the obvious reason that the aperture keeps enlarging and the liquid mass
behind is put in motion towards it; thus the pressure is increased and.
if the leak be not stopped, keeps increasing till it bears with irresistabl*;
force all obstructions away. A fatal example is recorded in the ancient
history of Holland : — an ignorant burgher, near Dort, to be revenged on
a neighbour, dug a hole through the dyke opposite the house of the latter,
intendin* to close it after his neighbor's property had been destroyed ;
but the water rushed through with an accelerating force, till all resistance
was vain, and the whole country became deluged. The ancients were
well aware of this accumulation of force in running waters. Allusions
to it are very common among the oldest \vriterB, and various maxims of
life were drawn from it. The be^nning of strife, says Solomon, ** is as
when one letteth out water" — the " breach of waters" — " breaking forth
of waters'* — ** rushing of mighty waters," &c. are frequently mentioned, to
indicate the irresistable influence of desolating evils when once admitted.

Thit the force which a running stream thus acquires may be made to


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Chap. 1.] Hydratdie Ram. 367

diive a portion of the liquid far above the source whence it flows, is obvi-
ous from several operations in nature. During a storm of wind, long
swelling waves in the open sea alternately rise and fall, without the crests
or tops of any being elevated much above those of the rest ; but when
they meet from opposite directions, or when their progress is suddenly
arrested by the bow of a ship, by rocks, or other obstacles, part of the
water is driven to great elevations. There is a fine example of this at the
Eddystone rocks — the heavy swells from the Bay of Biscay and from the
Atlantic, roll in and break with inconceivable fury upon them, so that vo-
lumes of water are thrown up with terrific violence, and the celebrated
light-house sometimes appears from this cause like the pipe of a fountain
enclosed in a stupendous ^'f^ d^eau. The light room in the old light-house
was sixty feet above the sea, and it was often buried in the waves, so im-
mense were the volumes of water thrown over it.

The hydraulic ram raises water on precisely the same principle : a
«)uantity of the liquid is set in motion through an inclined tube, and its es-
cape from the lower orifice is made suddenly to cease, when the momen-
tum of the moving mass drives up, like the waves, a portion of its own
volume to an elevation much higher than that from which it descended.
This may be illustrated by an experiment familiar to most people. Sup-
pose the lower orifice of a tube (whose upper one is connected to a reser-
voir of water) be closed with the finger, and a very minute stream be al-
lowed to escape from it in an upward direction — the tiny jet would rise
nearly to the surface of the reservoir^ it could not, of course, ascend
higher — ^but if the finger were then moved to one side so as to allow a
free escape till the whole contents of the tube were rapidly moving to the
exit, and the orifice then at once contracted or closea as before, the jet
would dart far above the reservoir; for in addition to the hydrostatic pres-
sure which drove it up in the first instance, there would be a new force
ocUng upon it, derived from the motion of the water. As in the case of
a hammer of a few pounds weight, when it rests on the anvil it exerts a
pressure on the latter with a force due to its weight only, but when put
in motion by the hand of the smith, it descends with a force that is equiva-
lent to the pressure of perhaps a ton.

Every person accustomed to draw water from pipes that are supplied
from very elevated sources, must have observed, when the cocks or dis-
charging orifices are suddenly closed, a jar or tremor communicated to the
pipes, and a sllappin^ sound like that from smart blows of a hammer. These
effects are produced by blows which the ends of the pipes receive from
the water; the liquid particles in contact with the plug of a cock, when it
is turned to stop the discharge, being forcibly driven up against it by those
constituting the moving mass behind. The philosophical instrument named
a toater hammer illustrates this fact. The effect is much the same as if a
solid rod moved with the same velocity as the water through the tube
until its progress was stopped in the same manner, except that its mo-
mentum would be concentrated on that point of the pipe against which it
struck, whereas with the liquid rod the momentum would be communi-
cated equally to, and might be transmitted from any part of, the lower end
of the tube ; hence it often occurs that the ends of such pipes, when made
of lead, are swelled greatly beyond their original dimensions. We have
seen some f of an inch bore, become enlarged to 1 J inches before they were
rupmred. At a hospital in Bristol, England, a plumber was employed
to convey water through a leaden pipe trom a cistern in one of the upper
stories to the kitchen below, and it happened that the lower end ot the
tube was Varst nearly every time the cock was used. After several at-


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368 WliUehursVs Water-Ram. [Book IV.

tempts to remedy the evil, it was determined to solder one end of a smailei
pipe immediately behind the cock, and to carry the other end to as high
a level as the water in the cistern; and now it was found that on shutting
the cock the pipe did not burst as before, but a jet of considerable height
was forced from the upper end of this new pipe : it therefore became ne-
cessary to increase its height to prevent water escaping from it — upon
which it was continued to die top of the hospital, being twice the height
of the supplying cistern, but where to the great surprise of those whc
constructed the work, some water still issued : a cistern was therefore
placed to receive this water, which was found veiy convenient, since it
was thus raised to the highest floors of the building without any extra
labor. Here circumstances led the workmen to the construction of a water-
ram without knowing that such a machine had been previously devised.

The first person who is known to have raised water by a ram, designed
for the purpose was, Mr. Whitehurst, a watchmaker of Derby, in England.
He erected a machine similar to the one represented by the next figure,
in 1772. A description of it was forwarded oy him to the Royal Society,
and published in vol. Iv, of their Transactions.

No. 167. Whiteharat^ Wat«r-EMb

A, represents the spring or reservoir, the surface of the water in w*iic<:
was of about the same level as the bottom of the cistern B. The nriain
pipe from A to the cock at the end of C, was nearly six hundred foot m
length, and one and a half inches bore. The cock was sixteen feet below
A, and furnished water for the kitchen offices, &c. When it was opened
the liquid column in A C was put in motion, and acquired a velocity due
to a fadl of sixteen feet ; and as soon as the cock was shut, the; momentum
of this long column opened the valve, upon which part of the water rushed
into the air-vessel and up the vertical pipe into B. This effect took place
every time the cock was used, and as water was drawn from it at short
intervals for household purposes, " from morning till night — all the days
in the year," an abundance was raised into B, without any exertion or

Such was the first water-ram. As an ori^nal device, it is highly honor-
able to the sagacity and ingenuity of its author; and the introduction of an
air vessel , without which all apparatus of the kind could never be made
durable, strengthens his claims upon our regard. In this machine he has
shown that the mere act of drawing water from long tubes for c rdinary
purposes, may serve to raise a portion of their contents to a higher level j
an object that does not' appear to have been previously attempted, or
even thought of. The device also exhibits another mode, besides tbat
by pressure engines, of deriving motive force from liquids thus drawii|
and consequently opens another way by which the immense power ex-
pended in raising water for the supply of cities, may again be gifen


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Chap. 1.] MofUgoyier*9 Bam. 369

out with the liouid from the lateral pipes. Notwithstanding the advan-
tages derived trom such 8Ui apparatus, under circumstances similar to
those indicated by the figure, it does not appear to have elicited the at-
tention of engineers, nor does Whitehurst himself seem to have been aware
of its adaptation as a substitute for forcing pumps, in locations where the
water draWn from the cock was not required, or could not be used. Had
he pursued the subject, it is probable the idea of opening and closing the
cock (by means of the water that escaped) with some such apparatus a«
figured in No. 160, would have occurred to him, and then his machine
being made self-acting, would hiive been applicable in a thousand loca-
tions. But these additions were not made, and the consequence was, that
the invention was neglected, and but for the one next to be described, it
would most likely have passed into oblivion, like the steam machines of
Branca, Kircher, and Decaus, till called forth by the application of the
same principle in more recent devices.

Whenever we peruse accounts of the labors of ingenious men, in search
of new discoveries in science or the arts, sympathy leads us to rejoice at
their success and to grieve at their failure 2 Hl^e the readers of a well
written novel who enter into the views, feelings and hopes of the hero ;
realize his disappointments, partake of his pleasures, and become interested
in his fate ; hence somethine like regret comes over us, when an indus-
trious experimenter, led by his researches to the verge of an important
discovery, is, by some circumstance diverted (perhaps temporarily) from
it ; and a more Ibrtunate or more sagacious rival steps in and bears off the

grize from his grasp— a prize, which a few steps more would have put
im in possession of. Thus Whitehurst with the water-ram, like Papin
with the steam-engine, discontinued his researches at the most interestmg
point — at the very turning of the tide that would have carried him to the
goal ; and hence the fruit of both their labors has contributed but to en-
hance the glory of their successors.

The Belter hydratdique of Montgolfier was invented in 1796. (Its au-
thor was a French paper maker, and the same gentleman who, in conjunc-
tion with his brother, invented balloons in 1782.) Although it is on the
principle of Whitehurst's machine, its invention is believed to have been
entirely independent of the latter. But if it were even admitted that
Montgolfier was acquainted with what Whitehurst had done, still he has,
by his improvements, made the ram entirely his own. He found it a
comparatively useless device, and he rendered it one of the most efficient
—it was neglected or forgotten, and he not only revived it, but gave it a
permanent place among hydraulic machines, and actually made it the
most interesting of them all. It was, previous to his time, but an embryo;
when, like another Prometheus, he not only wrought it into shape and
beauty, but imparted to it, as it were, a principle of life, that rendered its
movements self-acting ; for it requires neither the attendance of man, nor
any thing else, to keep it in play, but the momentum of the water it is
employed to elevate. Like the organization of animal life, and the me-
chanism by which the blood circulates, the pulsations of this admirable
machine incessantly continue day and night, lor months and years; while
nothing but a deficiency of the liquid, or defects in the apparatus can in-
duce it to stop. It is, compared to Whitehurst's, what the steam-engine
of Watt is to that of Savary or Newcomen.

Montgolfier positively denied having borrowed the idea from any one-
he claimed the invention as wholly his own, and there is no reason what-
ever to question his veratity. The same discoveries have often been, and
stiU are, made in the same and in distant countries, independently of each



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370 Mantgoifier's [Book IV

other. It is a common occurrence, and from the constitution of the hu-
man mind will always be one. A patent was taken out in England for
self-acting rams in 1797 by Mr. Boulton, the partner of Watt, and as no
reference was made in the specification to Montgolfier, many persons ima-
gined them to be of English origin, a circumstance that elicited some re-
marks from their author. " Cette invention (says Montgolfier) n'est point
d'origine Anglaise, elle appartient toute entidre k la France ; je declare
que j'en suis le seul inventeur, et que I'id^e ne m'cn a 6t4 foumie par
personne ; il est vrai qu'un de mes anus a fait passer, avec mon agrement,
a MM. Watt et Boulton, copie de plusieurs aessins que j'avais faits^de
cette machine, avec im m^moire detaill^ sur ses applications. Ce sont ces
mimes dessins qui ont 6t6 fiddlement copies dans la patente prise par M.
Boulton d Londres, en date du 13 D^cembre 1797 ; ce qui est une v^rite
dont il est bien ^loign^ de disconvenir, ainsi que le respectable M^Watt"
We have inserted this extract from Hachette, because we really supposed
on reading the specification of Boulton's patent in the Repertory of Arts,
(for 1798, vol. ix,) that ^e various modifications of the ram there des-

Online LibraryThomas EwbankA descriptive and historical account of hydraulic and other machines for ... → online text (page 55 of 90)