BOOK IV.

MACHINES FOR RAISING WATER, (CHIEFLY OF MODERN ORIGIN)INCLÜDING EARLY APPLICATIONS OF STEAM FORTHAT PURPOSE.

CHAPTER I.

Devices of the lower animals—Some animals aware that force is increased by the space throughwhich a body moves—Birds drop shell fish from great elevations to break the Shells—Death of iEschylus—Combats between the males of sheep and goats—Military ram of the ancients—Water rams—Wavea—Momentum acquired by running water—Examples—Whitehurst’s machine—Hydraulic ram of Mont-golfier—“ Canne hydraulique” and its modifications.

Op the machines appropriated to the fourth division of this work, (seepage 8,) centrifugal pumps and a few others have already been described.There remain to he noticed, the water ram, canne hydraulique, and de-vices for raising water by means of steam and other elastic fluids.

If the various operations of the lower animals were investigated, a thou-sand devices that are practised by man would be met with, and probablya thousand more of which we yet know nothing. Even the means by whichthey defend themselves and secure their food or their prey, are calculatedto impart useful information. Some live by stratagem, laying concealedtili their unsuspecting victims approach within reach—others dig pitfallsto entrap them; and others again fabricate nets to entangle them, andcoat the threads with a glutinous substance resembling the birdlime of thefowler. Some species distill poison and slay their victims by infusing itinto their blood; while others, relying on their muscular energy, suffocatetheir prey in their embraces and crush both body and bones into a pulpymass. The tortoise draws himself into his shell as into a förtress and bidsaefiance to his foes; and the porcupine erects around his body an array ofbayonets from which his enemies retire with dread. The strength of theox, the buffalo and rhinoceros is in their necks, and which they applywith resistless force to göre and toss their enemies. The elephant by hisweight treads his foes to death; and the horse by a kick inflicts a woundthat is often as fatal as the bullet of a rifle ; the space through which hisfoot passes, adding force to the blow.

There are numerous proofs of some of the lower animals being awarethat the momentum of a moving body is increased by the space throughwhich it falls. Of several species of birds which feed on shell fish, some,when unable to crush the Shells with their bills, carry them up in theair, and let them drop that they may be broken by the fall. (The Athe-nian poet iEschylus, it is said, was killed by a tortoise that an eagle drop-ped upon his bald' head, which the bird, it is supposed, mistook for a stone.)