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ey may be brought quite or nearly into a straight line, and made to produce great endwise pressure, when any force is applied to bring them into this position.

iscovered that the rise of a liquid in a tube, as in the barometer, is due to atmospheric pressure. See Barometer. Torricellian tube, a glass tube thirty or more inches in length, open at the lower end and hermetically sealed at the upper, such as is used in the barometer. -- Torricellian vacuum (Physics), a vacuum pr…

The sense by which pressure or traction exerted on the skin is recognized; the sense by which the properties of bodies are determined by contact; the tactile sense. See Tactile sense, under Tactile. The spider's touch, how exquisitely fine. Pope.

trument for arresting hemorrhage. It consists essentially of a pad or compress upon which pressure is made by a band which is tightened by a screw or other means.

A step or stepping; pressure with the foot; a footstep; as, a nimble tread; a cautious tread. She is coming, my own, my sweet; Were it ever so airy a tread, My heart would hear her and beat. Tennyson.

ll) with a trepan, so as to remove a portion of the bone, and thus relieve the brain from pressure or irritation; to perform an operation with the trepan.

is lined with tubbing and provided with an air lock, work being proceeded with under air pressure.

cars, the valve under each car, by means of which the brake is controlled by a change of pressure in the air pipe leading from the locomotive.

assemblage of members of wood or metal, supported at two points, and arranged to transmit pressure vertically to those points, with the least possible strain across the length of any member. Architectural trusses when left visible, as in open timber roofs, often contain members not needed for construction, or are built…

with some definite law; also, rarely, in artificial twinning (accomplished for example by pressure), the process by which this reversal is brought about. Polysynthetic twinning, repeated twinning of crystal lamellæ, as that of the triclinic feldspars. -- Repeated twinning, twinning of more than two crystals, or parts…

Having the properties exhibited by gases under very low pressures (one millionth of an atmosphere or less). Matter under this condition, which has been termed the fourth state of matter, is sometimes called radiant matter.

Not bending; not suffering flexure; not yielding to pressure; stiff; -- applied to material things. Flies o'er unbending corn, and skims along the main. Pope.

The tremulous tone produced by a peculiar pressure of the finger on a string, as of a violin.

The quality or condition of being urgent; insistence; pressure; as, the urgency of a demand or an occasion.

An apparatus for the measurement of low pressures.

The condition of rarefaction, or reduction of pressure below that of the atmosphere, in a vessel, as the condenser of a steam engine, which is nearly exhausted of air or steam, etc.; as, a vacuum of 26 inches of mercury, or 13 pounds per square inch. Vacuum brake, a kind of continuous brake operated by exhausting the a…

steam, water, etc., to pass into or out of a chamber so as to establish or maintain equal pressure within and without. -- Valve chest (Mach.), a chamber in which a valve works; especially (Steam Engine), the steam chest; -- called in England valve box, and valve casing. See Steam chest, under Steam. -- Valve face (Ma…

es constriction of the blood vessels. Such substances are used in medicine to raise blood pressure.

An automatic machine gun in which the mechanism is worked by the recoil, assisted by the pressure of gases from the muzzle, which expand in a gas chamber against a disk attached to the end of the barrel, thus moving the latter to the rear with increased recoil, and against the front wall of the gas chamber, checking th…

Vis mortua Etym: [L.] (Mech.), dead force; force doing no active work, but only producing pressure. -- Vis vitæ, or Vis vitalis Etym: [L.] (Physiol.), vital force. -- Vis viva Etym: [L.] (Mech.), living force; the force of a body moving against resistance, or doing work, in distinction from vis mortua, or dead force;…