Various forms of Pumps.

205

Chap. 5.]

provide his öwn, no one would ever think of borrowing his neigkbor’s,any more than be would ask for the loan of his tooth-pick. a

We are not sure that this plan of attenuating agreeable liquids, did notgive rise to that mode of drinking adopted by the luxurious Greeks andRomans, to which we have before alluded. Their drinking vessels werec'enerally horns, or were formed in imitation of them. At the small endof each a very minute opening was made, through which a stream ofdrops, as it were, descended into the mouth. Paintings found in Pom-peii, and other ancient monuments, represent individuals in the act of thususing them—while others, whose appetite for the beverage, or whosethirst was too keen to relish so slow a mode of allaying it, are seendrinking, not out of “the little end,” but out of the large end “of thehorn.” We have mentioned this circumstance because it appears to af-ford a solution of an old, but somewhat ambiguous saying.

CHAPTER V.

On bellows pumps: Great variety in the forms and materials of machines to raise water—Simple beilows pump—Ancient German pump—French pump—Gosset’s frictionless pump: Subsequently re-in-vented—Martin’s pump—Robison’s bag pump—Disadvantages of bellows pumps—Natural pumps inmen, quadrupeds, insects, birds, &c.—Reflections on them. Ancient vases figured in this chapter.

In the course of time a new feature was given to sucking tubes, bywhich they were converted into pumps: this was an apparatus for with-drawing the air in place of the mouth and lungs. In what age it was firstdevised, and by what people, are alike unknown. The circumstance thatoriginally led to it, was probably the extension of the length of suckingtubes, until the strength of the lungs was no longer sufficient to drawwater through them. In this way the bellows pump, the oldest of allpumps, we presume took its rise.

It should be borne in mind that an atmospheric pump is merely a con-trivance placed at the upper end of a pipe to remove the pressure of theatmosphere there, while it is left free to act on the liquid in which thelower end is immersed ; and farther, that it is immaterial what the sub-stance of the machine is, or what figure it is made to assume. Some per-sons perhaps may suppose that pumps seldom vary, and then but slightly,from the ordinary one in our streets, (the ancient wooderi one) but no ideacould be more erroneous; for few, if any, machines have undergone agreater number of metamorphoses. The body or working part, which isnamed the ‘ barrel’ and sometimes the ‘ chamber,’ so far from being alwayscylindrical, has been made square, triangulär, and elliptical;—itis notevenalways straight, for it has been bent into a portion of a circle, the centreof which formed the fulcrum of the lever and rod, both of which in thiscase being made of one piece : its materials have not been confined toWood and the metals, for pumps have been made of glass, stonewafe,stone, leather, canvas, and caoutchouc. Some have been construeted like

a In Shakespeare ’s time, “every guest carried his own knife, which he occasionallywhetted on a stone that hung behind the döor. One of these whetstones may be seenin Parkinson’s Museum. They were strangers at that period to the use of forks.”[Ritsons’s Notes on Shakespeare ’s Timon of Athens . Act i, Scene 2.]