218

Pumps in the 16th Century.

[Book II.

of that instrument. It has no valve or clack, but appears to be a modification of the one used in the old bilge pump, which was sometimes compared to a 'gunner's sponge.'

There are numerous proofs in old authors, that pumps were common in wells in the 15th century, since they are mentioned in the early part of the following one, as things in ordinary. In 1546, they were used to some extent in those of London. In the 'Practice of the New and old Phisicke,' by Conrad Gesner, (who died in 1565) translated by George Baker, 'one of the Queene's maiesties chiefe chirurgians in ordinary,' and dedicated to Elizabeth, (Lon. black letter, 1599,) is a description of a Florentine distilling apparatus, to which a portable pump was attached; the latter is described as "an instrument which is so formed that the water by sucking is forced to rise up and run forth, as the like practice is often used in pits of water or welles." Folio 215. The celebrated mathematician, necromancer, and alchymist, Dr. John Dee, who was frequently consulted by queen Elizabeth, had a pump in the well belonging to his house. In Beroald's commentary on the 44th proposition of Besson, (the chain of pots) he observes that it "operè sans intermission en tirant l'eau de tout puits facilement sans pompes." "a Sarpi, who first discovered the valves of the veins, compared them to those of a pump, 'opening to let the blood pass, but shutting to prevent its return.'

No. 87. A. D. 1511.

But pumps had not wholly, in the 16th century, superseded the old mode of raising water with buckets in European cities. At that time a great portion of the wells were open-of this, numberless intimations might be found. Thus in Italy, the poet Aurelli, who was made governor of a city by Leo X. was murdered by the inhabitants on account of his tyranny, and his body with that of his mule thrown into a well. In London, it was not till the latter part of the following century that the chain and pulley disappeared. This is evident from the following enactment of the common council of that city the year after the great fire. (1667) "And for the effectual supplying the engines and squirts with water, pumps are to be placed in all wells:"b-a proof that many were open and the water raised in buckets.

Pumps are also described in old works on husbandry, gardening, &c. from which it appears that they were often used to raise water for irrigation. In the Systema Agriculturæ, being the mystery of Husbandry discovered and laid open,' Lon. 1675, directions are given respecting various modes of making and working them; and it is particularly directed that the rods be made of such a length as to permit the suckers or 'upper boxes' to descend at every stroke below the surface of the water in the well; this it is observed, 'saves much trouble.' The same remark accompanies an account of windmills for watering land [pumps driven by them] in the old 'Dictionarum Rusticum.'

In the mines of Hungary pumps were early introduced, but at what period is uncertain. It is not improbable that those described by Agri

a Theatre des Instrumens, 1579. b Maitland's History of London, p. 297.

Chap. 6.]

Pumps in German Mines.

219

cola, were similar to such as were used in some of the same mines by the ancients, and have always formed part of the machinery for discharging water from them since the fall of the Roman empire. All that are figured in the De Re Metallica, are extremely simple, and with one exception are atmospheric or sucking pumps. They are all of bored logs. Some are single pumps, and are worked by men with levers, cranks, and also by a kind of pendulum. Others are double, triple, &c., and worked by water wheels. Of the last some are arranged in rows, and the piston rods raised by cams as in a stamping mill; the weight of the rods carrying them down. Others are placed in tiers one above another; the lowest one raises the water from the bottom of the shaft or well, and discharges it into a reservoir at its end: upper into this reservoir the next pump is placed, which raises it into a higher one, and so on to the top. A pump of this kind from Agricola, has been often republished. It was copied by Bockler and others. A figure of it is inserted in Gregory's Mechanics, Jamieson's Dictionary, &c.

We have selected No. 88, as a specimen of a single pump, and of upper and lower boxes. A, A, represent two of the latter; the upper part of one is tapered to fit it into the lower end of the pump log as is yet sometimes done. D, B, an upper box, of a kind occasionally used at the present time. The valve or

clack is a disk laid loosely over the apertures, and is kept in its place by the rod, which passes through its centre and admits it to rise and fall. C, the conical sucker referred to, p. 214. The annexed figure of a double pump is from Fludd's works. It appears to have been sketched by him while in Germany, from one in actual use. It is represented as worked by a water wheel, that, by means of cog wheels transmitted motion to the horizontal shaft; the cams on which alternately depressed one end of the levers to which the pump rods were attached, and thus raised the latter. They descended by their own weight, as will appear from an inspection of the figure. The separate view of a rod is intended to show the application of cranks on the horizontal shaft, in place of cams and le

No. 89. Double Pump in German mines. A. D. 1618.

220

The Pump confined chiefly to civilized States.

[Book II. vers. The lower ends of the pumps are inserted in baskets which act as strainers. A double series of pumps, (one over the other) as employed in a mine at Markirch in Germany, is also figured by Fludd. It is interesting on account of the mode of communicating motion to the rods. A crank on the axle of a water wheel imparts motion to a walking beam, as in a steam engine; (in the latter the operation is reversed) and the pump rods are attached to both ends of the beam.a

The idea may probably occur to the general reader, that the mechanical talent and enterprise of the preceding and present century, which have produced so many original machines and scarcely left an ancient device unimproved, must have imparted to the old atmospheric pump new features, and made it capable of increased results. It is true that few devices have occupied a greater share of attention, and on none have more efforts to improve them been bestowed; but how far these have been successful may be inferred from the fact that notwithstanding the endless variety of forms into which its working parts have been changed, and the great number of alledged improvements in suckers, pistons, valves, &c. the machine as made by the ancients, still generally prevails; so that were some of their pump makers to reäppear, and visit their fellow craftsmen throughout the world, they would find little difficulty in resuming their occupation.

The pump, although a simple instrument, is confined chiefly to civilized states, while the extent to which it is employed, indicates pretty correctly the degree of refinement attained by the people who possess it. Whether it was known to the Egyptians under the Pharaohs or not, may be a question; but when Egypt under the Greeks realized a partial revival of her former glory, the forcing pump we know made its appearance there; and under the second Ptolemy, when that country was a school for the rest of the world, its most valuable modifications were known. In succeeding ages, the atmospheric pump has been a regular attendant on the revival of learning and of the arts. Wherever these have made the most progress, there the pump is mostly used. In Germany, France, Holland, Great Britain, and the United States, it is most extensively employed. In Spain, Portugal, Mexico and South America, but partially so. In Turkey, Egypt, Greece, &c. still less; while in Asia and Africa, generally, it is unknown. Egypt, even under the auspices of Mohammed Ali, is not yet prepare to receive it again. Its history in any country is that of the people. Take Russia for an example: of the devices for raising water there, we are informed the inhabitants use the swape, a rope passing over a pulley, (Nos. 13 and 14) a drum on which a rope is wound, (No. 23) horizontal and vertical wheels, and lastly pumps; these last it is said, were formerly very rare, but are now become common. Just so of the people, they were formerly very rude and ignorant, but are now becoming enlightened.

a De Naturæ Simia seu Technica macrocosmi historia, pp. 453, 455.

b As regards a knowledge of the pump in China, see remarks on Chinese bellows, in the next Book.

Lyell's Character of the Russians, and a detailed history of Moscow. Lon. 1823, p. 63.

Chap. 7.]

Metallic Pumps.

221

CHAPTER

VII.

Metallic pumps-Of more extended application than those of wood- Description of one-Devices to prevent water in them from freezing-Wells being closed, no obstacle in raising water from them-Application of the atmospheric pump to draw water from great distances as well as depth-Singular circumstance attending the trial of a Spanish pump in Seville-Excitement produced by it-Water raised to great elevations by atmospheric pressure when mixed with air-Deceptions practised on this principle-Device to raise water fifty feet by atmospheric pressure-Modifications of the pump innumerable -Pumps with two pistons-French marine pump-Curved pump-Muschenbroeck's pump-Centrifugal pump-West's pump-Jorge's improvement-Original centrifugal pump-Ancient buckets figured in this chapter.

THAT the public hydraulic machinery of the Romans was of the most durable materials sufficiently appears from Vitruvius. The chain of pots described by him was, contrary to the practice in Asia and Egypt, wholly of metal-the chain was of iron and the buckets of brass. The pumps

of Ctesibius that were employed in raising water to supply some of the public fountains, he informs us, were also of brass and the pipes of copper or lead. Some of the oldest pumps extant in Europe are formed altogether of the latter. Leaden pumps were very common in the 16th century. They are mentioned by old physicians among the causes of certain diseases in families that drank water out of them. The pump of the celebrated alchymist, Dee, alluded to in the last chapter, was a leaden one; and which he expected to be able to transmute into gold, by means of the elixir or the philosopher's stone, which he spent his life and fortune in seeking. In the vicinity of some English lead mines such pumps have for many centuries been in use. The Italian pump that led to the discovery of atmospheric pressure was also a metallic one.

The introduction of metals in the construction of pumps greatly extended their application and usefulness, for they were then no longer required to be placed directly over the liquids they raised. Those of wood were necessarily placed within the wells out of which they pumped water; but when the working cylinder and pipes were of copper or lead, the former might be in the interior of a building, while the reservoir or well from whence it drew water, was at a distance outside; the pipes forming an air-tight communication between them under the surface of the ground.

The following figure, (No. 90) represents a common metallic sucking pump; the cylinder of cast-iron or copper, and the pipes of lead. It will serve to explain the operation of such machines in detail, and to show the extent of their application. When this pump is first used, water is poured into the cylinder to moisten the leather round the sucker, and the pieces which form the clacks or valves; it also prevents air from passing down between the sucker and the sides of the cylinder when the former is raised. Now the atmosphere rests equally on both orifices of the pipe, the open one in the well, and the other covered by a valve at the bottom of the cylinder: in other words, it presses equally on the water in the cylinder and in the well which covers both;a but when by

Not absolutely so, or in a strict philosophical sense, but the difference is so slight in an altitude of 25 or 28 feet, (the ordinary limits) as to be inappreciable in a practical point of view.

222

Common Pumps.

[Book II. the depression of the handle or lever, the sucker is raised, this equality is destroyed, for the atmospheric column over the cylinder, and consequently

ન

over the valve O is lifted up, and sustained by the sucker alone; it therefore no longer presses on the upper orifice, while its action on the lower one remains undiminished. Then as the external air cannot enter the pipe to restore the equili brium except through its orifice immersed in the well; in its efforts to

do so, (if the expression is allowable) it necessarily drives the water before it on every ascent of the sucker, until the air previously contained in the pipe is expelled, and both pipe and cylinder become filled with water.

vious.

The subsequent operation is obWhen the sucker descends, the clack on its upper surface is raised by the resistance of the water through which it passes; and when at the bottom of the cylinder, this clack closes by its own weight: so that when the sucker is again elevated, besides overcoming the resistance of the atmosphere, it carries up all the water above it, and which it discharges at the spout-at the same time the atmosphere resting undisturbed on the water in the well, pushes up a fresh portion into the vacuity formed in the cylinder, and the valve O prevents its return.

No. 90. Common Metallic Pump.

The horizontal distance between the cylinder or working part of the pump and the well is, in theory unlimited, but in practice it seldom exceeds one or two hundred feet. In all cases where long pipes are used, their bore should be enlarged in proportion to their length, or the velocity with which the sucker is raised, should be diminished; and for this reason-time is required to overcome the inertia and friction of long columns of water in pipes; hence a sucker should never be raised faster than the pipe can furnish water to fill the vacuity formed by its ascent. In pumps whose pipes have too small a bore, it frequently happens that the sucker is forcibly driven back when quickly raised, because the water had not time to rush through the pipe and fill the vacuity in the cylinder as rapidly as it was formed. The bore of wooden pumps being equal throughout, the water is not pinched or wire-drawn while passing through them, as in most of those of metal. This is one reason why they generally work easier than the latter. It is immaterial in what part of the pipe the valve O is: it is usually placed at the upper end for the convenience of getting to it when requiring repairs. When it fits close to its seat, the water always remains suspended in the pipe, (unless the latter should be defective) as mercury is sustained in a barometer tube.

In cold climates it is a matter of some importance to prevent water in pumps from freezing. Metallic pumps are, from the superior conducting property of their material, more subject to this evil than those of wood. Of various devices a few may be mentioned. The old mode of enclosing