TROY n.
s, and the like, are weighed. It was so named from Troyes, in France, where it was first adopted in Europe. The troy ounce is supposed to have been brought from Cairo during the crusades. In this weight the pound is divided into 12 ounces, the ounce into 20 pennyweights, and the pennyweight into 24 grains; hence, the t…
VASCULAR a.
e, as all flowering plants and the higher cryptogamous plants, or those of the class Pteridophyta. Cf. Cellular plants, Cellular. -- Vascular system (Bot.), the body of associated ducts and woody fiber; the fibrovascular part of plants. -- Vascular tissue (Bot.), vegetable tissue composed partly of ducts, or sap tube…
VEGETABLE a.
l and sporophoric, the other sexual and oöphoric. Divided into Vascular Acrogens, or Pteridophyta, having the sporophoric plant conspicuous and consisting partly of vascular tissue, as in Ferns, Lycopods, and Equiseta, and Cellular Acrogens, or Bryophyta, having the sexual plant most conspicuous, but destitute of vascu…
VISUAL a.
assing through the colors, red, orange, and yellow, and then disappearing. Also called rhodopsin, and vision purple. See Optography. -- Visual ray, a line from the eye, or point of sight. -- Visual white (Physiol.), the final product in the action of light on visual purple. It is reconverted into visual purple by the…
WOOD n.
er Apple, and Pine weevil, under Pine. (b) The larva of any one of various species of lepidopterous insects, especially of the clearwing moths, as the peach-tree borer (see under Peach), and of the goat moths. (c) The larva of various species of hymenopterous of the tribe Urocerata. See Tremex. (d) Any one of several b…