EYEPIECE n.
imating eyepiece. See under Collimate. -- Negative, or Huyghenian, eyepiece, an eyepiece consisting of two plano-convex lenses with their curved surfaces turned toward the object glass, and separated from each other by about half the sum of their focal distances, the image viewed by the eye being formed between the tw…
FAUCET n.
, or other vessel, in such quantities as may be desired; -- called also tap, and cock. It consists of a tubular spout, stopped with a movable plug, spigot, valve, or slide.
FERRICYANIDE n.
erricyanide (Chem.), red prussiate of potash; a dark, red, crystalline salt, K6(CN)12Fe2, consisting of the double cyanide of potassium and ferric iron. From it is derived the ferrous ferricyanate, Turnbull's blue.