Page:Dictionary of aviation.djvu/154

 130 DICTIONARY OF AVIATION

sisting of a wetebulb and a dry^bulb thermometer with a scale and pointer between them.

hygrometer ^lai'gzemi-taz n. an instrument for mesuring the humidity of air and other gases; a device for determin- ing the degree of saturation of the atmosfere with water? vapor.

chemical hygrometer, a hygrometer in which a known volume of air is past over a hygroscopic substance, as cal- cium chloride, containd in a drymg^tube.

condensing hygrometer, a hygrometer which operates by means of the condensation of the atmosferic water^vapor ; a dew-point hygrometer.

Daniell hygrometer, a condensing or dew-point hygrome- ter consisting of a bent glass tube ending in two bulbs and working by means of the evaporation of ether.

dew-point hygrometer, a hygrometer, as that of Daniell, by means of which the dew-point is first obtaind, and thence the humidity of the air is calculated; a condensing hygrometer.

Dufour's hygrometer, a hygrometer which operates by diffusion of air thru a porous diafram on one side of which the air is kept saturated with aqueous vapor.

Edelmann's hygrometer, a hygrometer especially adapted for mesuring the tension or volume of the gaseous water* vapor in the air, without taking account of fog^particles.

Mason's hygrometer, the psychrometer or weteand^dry bulb as arranged by Mason.

Regnault's hygrometer, a condensing or dew-point hy- grometer invented by Regnault

RenouxtMatern hygrometer, a hygrometer by which the quantity of water^vapor required in order to saturate a a given volume of air is first determind and the humidity thence calculated.

Trouton's electrical dew-point hygrometer, a hygrometer operating by the deposition of a film of dew en a polisht metallic surface and the consequent closing of an electric circuit thru this moisture.

Trouton's gravimetric recording hygrometer, a hygrome- ter which operates by recording the weight of a hygro- metic or meisture^abserbing body by means of a stylus n a revolving drum. hygrometric ,hai-gz3 / metik adj.

1. of hygrometry ; hygrometical ; also, hygroscopic.

hygrometric balance, a form of hygroscope.

hygrometric state, the state of the atmosfere as to hu- midity or water^vapor.

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