Known to old Pump Makers.

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Chap. 3.]

to fourteen inches seven lines,) while on the highest ridge of the Hima-lajas, it would scarcely raise it eight or ten feet. Without a knowledgeof aerial pressure, it is obvious, that engineers who visit Mexico , and theupper regions of South America , &c. might get into a quandary greatlymore perplexing than that in which the Florentine was, when he appliedto Galileo : but we believe the period has nearly gone by, for mechanicsto rernain ignorant of those principles of Science , upon which their profes-sions are based.

It perhaps may be asked, Were the limits to which water canbe raisedby the atmosphere not known before Galileo ’s time 1 Undoubtedly theywere. Pump makers must always have beeil acquainted with them; al-though philosophers might not have noticed the fact or paid any attentionto the subject. Why then did the Italian artists make such a one as thatto which we have referred % Simply because they were ordered to doso, as any mechanic would now do under similar circumstances : at thesame time they declared that it would not raise the water, although theycould not assign any reason for the assertion. It was indeed impossiblefor ancient pump makers to have remained ignorant of the extent to whichtheir machines were applicable. A manufacturer of them would naturallyextend their application, as occasions occurred, to wells of every depth,until he became familiär with the fact that the power which caused the■water to ascend, was limited—and until he detected the limits. Afterusing a pump with success, to raise water twenty-five or thirty feet,when he came to apply it to wells of forty or fifty feet in depth withoutlengthening the cylinder, he would necessarily learn the important, andto him mysterious fact, that the limits were then exceeded: and afterprobably going through similar examinations and consultations, as thosewhich took place at Florence in the 17th Century, the unvarying resultwould become so firmly established, that every workman would learn ittraditionally, as an essential part of his profession : and if in succeedingages, the knowledge of it became lost, the experience of every individualpump maker must have soon taught him the same truth. Attempts thensimilar to those of the Florentine engineer occurred frequently before, butleading to no important result, the particulars of them have not been pre-served; nor is it probable that those relating to the Italian experimentwould have been, had not the father of modern philosophy been consulted,and had not his pupil Torricelli taken up the subject.

CHAPTER III.

Ancient Experiments on air—Various applications of it—Siphons used in ancient Egypt—Primitiveexperiraents with vessels inverted in water—Suspension of liquide in them—Ancient atmospheric sprink-iing pot—Watering Gardens with it—Probably referred to by St. Paul and also by Shakespeare—Glass«prinkling vessel, and a wine taster from Pompeii—Religious uses of sprinkling pots among the ancientheathen—Figure of one from Montfaucon—Vestals—Miracle of Tutia carrying water in a sieve, describ-ed and explained—Modern liquor taster and dropping tubes—Trick performed with various liquidsby a Chinese juggler—Various frauds of the ancients with liquids—Divining cups.

Notwithstanding the alledged ignorance of the ancients respecting thephysical properties of the atmosphere, there are circumstances related inhistory which seem to indicate the reverse ; or which, at any rate, show