TIDE n.
r), acting unequally on the waters in different parts of the earth, thus disturbing their equilibrium. A high tide upon one side of the earth is accompanied by a high tide upon the opposite side. Hence, when the sun and moon are in conjunction or opposition, as at new moon and full moon, their action is such as to prod…
VALVE n.
one above another, which rest upon two corresponding seats when the valve is closed. -- Equilibrium valve. (a) A balance valve. See under Balance. (b) A valve for permitting air, steam, water, etc., to pass into or out of a chamber so as to establish or maintain equal pressure within and without. -- Valve chest (Mac…
VIRTUAL a.
Quincey. Principle of virtual velocities (Mech.), the law that when several forces are in equilibrium, the algebraic sum of their virtual moments is equal to zero. -- Virtual focus (Opt.), the point from which rays, having been rendered divergent by reflection of refraction, appear to issue; the point at which converg…
WHEEL n.
at of the axle. Called also axis in peritrochio, and perpetual lever, -- the principle of equilibrium involved being the same as in the lever, while its action is continuous. See Mechanical powers, under Mechanical. -- Wheel animal, or Wheel animalcule (Zoöl.), any one of numerous species of rotifers having a ciliated…