208

Gosset and Deuille's Pump.

[Book II.

A neat and perhaps the best modification of these machines was devised about the year 1732, in Paris, by Messrs. Gosset and Deuille. It was described by Belidor in 1739, and by Desaguliers in 1744, as "a piston without friction." It consists of a circular piece of leather pressed into

the form of a deep dish, or of a low crowned hat with a wide rim. This rim is secured by bolts and screws between two flanches of a pump cylinder, forming an air tight joint-the part corresponding to the body of the hat fits loosely into the cylinder; and the crown is strengthed by a circular plate of metal of the same size and riveted to it. In the centre of this plate an opening is made and also through the leather for the passage of the water, and covered by a valve opening upwards like the ordinary sucker of a pump. The forked end of the pump-rod is secured to this plate. (See figure.) When the rod is raised, the bottom of the dish or hat is above the flanch, and when down it is pushed inside out as shown in the cut. Thus, by alternately elevating and depressing it, the water is raised as in the common pump. This piston is described in Vol. VI, of Machines approved by the French Academy for 1732, p. 85, as the invention of M. Boulogne.

No. 83. Gosset and Deuille's Pump.

The great advantage of this pump is in the sucker or piston not rubbing against or even touching the sides of the cylinder, hence there is no friction to overcome from that source, and the leather is consequently more durable; but the length of stroke is much less than in common pumps, it seldom exceeding six or eight inches, lest the leather should be overstrained in pressing it deeper. Large pumps of this description were worked in the mines of Brittany incessantly during three or four months without requiring any repair. India-rubber, and canvas saturated or coated with it, have been successfully used in place of leather. Some modifications of the sucker have also been introduced.

This pump was re-invented in England some years ago, and made considerable noise under a new name. See London Mechan, Magazine, and Register of Arts, 1826-29; also the Journal of the Franklin Institute for 1831, vol. vii, 193. In 1766, Mr. Benjamin Martin, the well known author of Philosophia Britannica' and other scientific works, proposed a good double pump of this kind for the British navy-a figure and description of it may be seen in Vol. XX. of Tilloch's Philosophical Magazine.

Dr. Robison, in the second volume of his Mechanical Philosophy, proposed what has been named an improvement on the last pump. His device is however little else than the old bellows pump. A figure of it and his description are annexed.

A, B, (No. 84) represents a wooden trunk or cylinder of metal, having a a spout at the upper part, and the lower end closed by a plate, the opening in which is covered by a clack valve E, as in No. 83. To this plate is secured the open bottom of a long cylindrical bag, the upper end being fixed to the round board F. "This bag may be made of leather or of double canvas, a fold of thin leather or of sheepskin being placed between the two

Chap. 5.]

F

folds. The upper end of the bag should be firmly tied with a cord in a groove turned out of the rim of the board at F. Into this board is fixed the fork of the piston rod, and the bag is kept distended by a number of wooden hoops or rings of wire, fixed to it at a few inches distance from one another, and kept at the same distance by three or four cords binding them together, and stretching from the top to the bottom of the bag. Now let this trunk be immersed in the water: it is evident that if the bag be stretched from the compressed form which its own weight will give it by drawing up the piston rod, its capacity will be enlarged, the valve F will be shut by its own weight, the air in the bag will be rarefied, and the atmosphere will press the water into the bag. When the rod is thrust down again, the water will come out at the valve F, and fill part of the trunk. A repetition of the operation will have a similar effect; the trunk will be filled, and the water will at last be discharged at the spout." The operation is precisely the same as in No. 81.

No. 84. Bag Pump.

"Here is a pump without friction and perfectly tight; for the leather between the folds of canvas renders the bag impervious both to air and water. We know from experiment that a bag of six inches diameter made of sail cloth No. 3, with a sheepskin between, will bear a column of fifteen feet of water, and stand six hours work per day for a month, without failure; and that the pump is considerably superior in effect to a common pump of the same dimensions. We must only observe that the length of the bag must be three times the intended length of the stroke, so that when the piston rod is in its highest position, the angles or ridges of the bag may be pretty acute. If the bag be more stretched than this, the force which must be exerted by the laborer becomes much greater than the weight of the column of water which he is raising."

But after all that can be said in favor of bellows pumps, they have their disadvantages. A prominent one is this: when the leather or other material of which they are formed is worn out, a practical workman, who is not to be obtained in every place, is required to renew it. Unlike replacing the leather on an ordinary 'sucker', which a farmer or a sailor on ship-board can easily accomplish, the operation requires practice to perform it efficiently, and the expense both of time and materials is much greater than that of similar repairs to the common pump. For these and other reasons, bellows pumps have never secured a permanent place among staple machines for raising water, and the old cylindrical pump still retains the preeminence, notwithstanding the almost innumerable projects that have been brought forward to supersede it.

The preceding machines resemble in some degree the apparatus for drinking which the Creator has furnished to us and to such quadrupeds as do not lap. When an ox or a horse plunges his mouth into a stream, he dilates his chest and the atmosphere forces the liquid up into his stomach precisely as up the pipe of a pump. It is indeed in imitation of these natural pumps that water is raised in artificial ones. The thorax is the pump; the muscular energy of the animal, the power that works it; the throat is the pipe, the lower orifice of which is the mouth, and which he must necessarily insert into the liquid he thus pumps into his stomach;

210

Natural Pumps.

[Book II. and whenever the depth of water is insufficient to cover the opening between his lips, the animal instinctively draws closer those portions of them above it, and contracts the orifice below, just as we do under similar circumstances, and which we constantly practice in sipping tea or coffee from a cup, or any other beverage of which we wish to partake in small quantities. The capacious chest of the tall camel, or of the still taller cameleopard or giraffe, whose head sometimes moves twenty feet from the ground, is a large bellows pump which raises water through the long channel or pipe in his neck. The elephant by a similar pneumatic apparatus, elevates the liquid through that flexible suction pipe,' his proboscis ; and those nimble engineers, the common house-flies, raise it through their minikin trunks in like manner.

We may here remark, that among the gigantic animals which in remote ages roamed over this planet, and which quenched their thirst as the ox does, there could have been none which stood so high as to have their stomachs thirty feet above the water they thus raised into them. And on the table lands of Mexico, and the still higher regions of Asia, Africa, and South America, animals of this kind, if such there were, must have had their stomachs placed still lower.

The mandibles of some insects are hollow, and are used as sucking pumps. They serve also sometimes as sheaths to poniards, with which nature has furnished them, as weapons of offence and defence. Those of the lion-ant are pierced, and "no doubt act as suckers." This little animal constructs a minute funnel-shaped excavation in dry sand, and covering its body at the bottom lays in wait, like an assassin, for its prey: "no sooner does an industrious ant, laden perhaps with its provision, approach the edge of the slope, than the finely poised sand gives way, and the entrapped victim rolling to the bottom, is instantly seized and sucked to a shadow by the lurking tyrant, who, soon after by a jerk of his head tosses out the dead body." Weasels and other animals suck the blood of their prey. The tortoise drinks by suction, for which purpose he plunges his head deep into the fluid, so as even to cover his eyes. There are several species of birds denominated 'suctorial' on account of their obtaining food by means of atmospheric pressure, which they bring into action by apparatus analogous to the pump. The grallatores or waders, "suck up their food" out of water.

It is impossible to contemplate the structure and habits of animals, without being surprised at the extent to which this principle of raising liquids has been adopted by the Almighty in the formation of insects, reptiles, fishes, birds, amphibia and land animals; and also at its adaptation to their various forms, natures, and pursuits. Had we the necessary knowledge of their physiology, we would desire no greater pleasure, no other employment than to examine and describe these natural pneumatic machines, and the diversified modes of their operation.

For other natural pumps, see remarks at the end of Chapter 2, on bellows forcing pumps, in the next Book.

The vessels or vases figured in this chapter are ancient. Those in which the tubes are inserted in illustrations Nos. 80 and 81, are of glass; the one under the pump spout in No. 83, is a bronze bucket; all from Pompeii. The latter is referred to at page 67. The globular vessel in No. 84, is a figure of a brazen cauldron, also Roman, from Misson. See page 19 of this volume.

Chap. 6.]

The Common Atmospheric Pump.

211

CHAPTER VI.

The atmospheric pump supposed by some persons to be of modern origin-Injustice towards the ancients Their knowledge of hydrodynamics-Absurdity of an alledged proof of their ignorance of a simple principle of hydrostatics-Common cylindrical pump-Its antiquity-Anciently known under the name of a siphon-The antlia of the Greeks-Used as a ship pump by the Romans-Bilge pump-Portable pumps-Wooden pumps always used in ships-Description of some in the U. S. Navy -Ingenuity of sailors-Singular mode of making wooden pumps, from Dampier-Old draining pumpPumps in public and private wells-Ir mines-Pump from Agricola, with figures of various boxesDouble pump formerly used in the mines of Germany, from Fludd's works-The wooden pump not improved by the moderns-Its use confined chiefly to civilized states.

SOME persons are unwilling to admit that the atmospheric pump was known to the ancients, and yet they are unable to prove its origin in later times or by more recent people. The passages in ancient authors in which it is supposed to be mentioned or alluded to, are deemed inconclusive, because the terms by which it is designated were also applied to other devices.

To confine the knowledge of the ancients to such departments of the arts as are either expressly mentioned or referred to in Greek and Roman authors, and to those, specimens of which have been preserved to our times, is neither liberal nor just. Let us suppose Europe and the United States, in the course of future time, thrown back into barbarism, and all records perished, save a few fragments of the works of our dramatists, poets and historians;-and that after the lapse of some 1500 or 2500 years these should be discovered-and also some relics of our architecture, pottery, and works in the metals: Now we should think the writers of those days illiberal in the extreme, who should conclude that we were ignorant of nearly all branches of science and of the arts; and of every machine which was not particularly mentioned or illustrated in the former or of which specimens were not found among the latter. And yet something like this, has been the treatment which the ancients have received at our hands.

It cannot however be denied, that remains of their works still extant, exhibit a degree of skill in architecture, sculpture, metallurgy, pottery, engraving, &c. which excels that of modern artists. And as regards their knowledge of hydrodynamics-let it be remembered, that we are indebted to them for canals, aqueducts, fountains, jets d'eau, syringes, forcing pumps, siphons, valves, air vessels, cocks, pipes of stone, earthenware, wood, of lead and copper: yet notwithstanding all these, and their numerous machines for raising and transferring water, and the immense quantities of tubes for conveying it, which are found scattered over all Asia as well as Italy and Greece, it has been gravely asserted, that they were ignorant of one of the elementary and most obvious principles of

a It was remarked by the late Mr. Wedgewood, who was doubtless the most skilful manufacturer of porcelain in our own times, that the famous Barbarini Vase afforded evidence of an art of pottery among the ancients of which we are as yet ignorant, even of the rudiments. Edin. Encyc. vol. ii, 203.

The vast quantities of leaden pipes found at Pompeii induced the Neapolitan goverument to sell them as old metal. Pompeii, vol. i, 104.

212

The Antlia,

[Book II. hydrostatics: viz. that by which water in open tubes finds its own level: a fact, of which it may safely be asserted, it was impossible for them not to have known-a fact with which the Indians of Peru and Mexico were familiar; and one expressly mentioned by Pliny: "water, (he observes) always ascends of itself at the delivery to the height of the head from whence it gave receipt-if it be fetched a long way, the work [pipe] will rise and fall many times, but the level [of the water] is still maintained." Besides the testimony of Pliny, fountains and jets d'eau are incontrovertible proofs that a knowledge of the fact is of stupendous antiquity; they having been used in the east from immemorial ages.

But the proof adduced to establish their ignorance in this particular, is as singular as the position it is brought forward to sustain, since it equally establishes our own ignorance of the same principle! It has been said, had the ancients known that water finds its level at both extremities of a crooked tube, they would have conveyed it through pipes to supply their cities, instead of erecting those expensive aqueducts which were among the wonders of the world, and remains of which still strike the beholder with admiration:-in reply to this it need only be observed, that should any remains of the Croton aqueduct, now constructing to supply this city (New-York) with water, be found two thousand years hence, they may, by the same argument, be adduced as proofs that the present engineers of the United States were ignorant that water poured into an inverted siphon would stand at the same level in both its branches.

The fact is, the ancients did sometimes convey water over eminences in siphons of an easy curvature. And aqueducts were in some few instances carried through valleys by inverted siphons. In the reign of Claudius, an aqueduct was formed to convey water from Fourvières to the highest part of the city of Lyons. As valleys of great depth were in the line of its course, works of an enormous expense would have been required, which might have prevented the execution of the project; consequently, instead of an elevated canal, leaden pipes were substituted; forming an inverted siphon.b

It is uncertain when or by whom the common atmospheric pump was invented. It is supposed to have been known to the old Egyptians, and to have been used in the ship in which Danaus and his companions sailed to Greece. As the antlia of the Greeks, it could not have originated with Ctesibius, to whom it has sometimes been attributed, since it or some other machine or device is mentioned under that name, by Aristophanes and other writers who flourished ages before him.d There are other indications that it was previously known, for either it or something very like it is mentioned under the name of a siphon. This term it is known was a generic one, being applied to hollow vessels, as funnels, cullenders, pipes; and generally to instruments that either raised or dispersed water, as syringes, catheters, fire-engines, sprinkling-pots, &c. That the machine to which we refer raised water by 'suction,' is apparent from ancient allusions to it. According to Bockler, "the Platonic philosophers asserted that the soul should partake of the joys of heaven as through a siphon;" and by it Theophrastus explained the ascent of marrow in bones; and Columella the rise of sap in trees. In these instances, it is obvious that neither the ordinary siphon nor the syringe could be intended, but the atmospheric pump; a machine that Agricola described as a

a Fosbroke's Encyc. Antiq. i, 41. Hydraulia, Lon. 1835, p. 254. See Edin. Encyc. Art. Chronology, vol. vi, 263. d Robinson's Antiquities of Greece, cap. 4. On Military Affairs. e See Ainsworth's Dict.