BOOK II.

MACHINES FOR RAISING WATER BY THE PRESSURE OF THEATMOSPHERE.

CHAPTEE I.

On machines that raise water by atmospheric pressure—Principle of their action formerly unknown—Suction a chimera—Ascent of water in pumps incomprehensible without a knowledge of atmosphericpressure—Phenomena in the Organization, habits, and motions of aniraals—Rotation of the atmospherewith the earth—Air tangible—Compressible—Expansible—Elastic—Air beds—Ancient beds and bed-steads—Weight of air—Its pressure—Examples—American Indians and the air pump—Boa Constrictor—Swallowing oysters—Shooting bullets by the rarefaction of air—Boy’s sucker—Suspension of fliesagainst gravity—Lizards—Frogs—Walrus—Connection between all departments of knowledge—Suck-ingfish—Remora—Lampreys—Dampier—Christopher Columbus at St. Domingo—Ferdinand Columbus—Ancient fable—Sudden expansion of'air bursting the bladders of fish—Pressure of the atmosphere onliquids.

With the last chapter we concluded our remarks on machines em-braced in the first general division of the subject, (see page 8) and now /proceed to those of the second ; viz. such as raise water by means of theweight or pressure of the atmosphere. These form a very interestingdass—they are genuine philosophical instruments, and as such may serveto exhibit and illustrate some of the most important truths of natural phi-losophy. The principle upon which their action depends was formerly un-known, and even now, a person, however ingenious, while ignorant of thenature and properties of the atmosphere, would be utterly unable to ac-count for the ascent of water in them. Having no idea of the cause ofthis ascent, except the vague one of suction, he would feel greatly embar-rassed if vequired to explain it. And when informed tbat there really isno such thing in nature as suction, but that it is a mere chimera, having noexistence except in the imagination, the task would be attended with in-snperable difficulties. Perhaps he would have recourse to a commonpump, to trace, if possible, the Operation in detail; if so, he would natural-ly begin with the first mover, or the pump handle, and would look forsome medium, by which motion is transmitted from it, to the water in thewell; but, however close the scrutiny might be made, he would be una-ble to detect any; and as a matter of course, while a Connection betweenthem, i. e. between the mover and the object moved, could not be discov-ered, it would be impossible for him satisfactorily to account for the phe-nomenon. If “ a body cannot act where it is not present,” as the sucker°f a pump, on water at a distarice from it, how could such a person ac-count for the ascent of that water in obedience to the movements of thesucker 1 And how could he explain the process by which it was elfected,