C, AIR. 



Aerostat'ics (Cr. aa; air, and sUilos, sustaining). — The sci- 

 cncf' wliifh treats of the equilibrium of elastic fluids^ or 

 (if liodics sustained in tliem. 



Astro-Meteorol'ogy HJr. axtron, a star, and meteorology). — 

 Tlif art <if foretelling the weather from the aspect of the 

 moon and stars. 



Atmol'ogy (Gr. ntmon, vapor, and loyos, discourse). — That 

 hraiK-h of science which treats of the laws and phenomena 

 of iKjucons vapor. 



Barom'eter ((ir. haros, weight, and metron, measure). — An 

 instrument for measuring the weight or pressure of the 

 atmosphere. 



Brontd'ogy (Gr. Ironte, thunder, and logos, discourse). — A 

 discourse or dissertation upon thunder, containing an ex- 

 ]ihiiiation of its causes and phenomena. 



Cyanom'eter (Gr. kuanos, blue, and metreo, I measure). — An 

 instrument to ascertain degrees of blueness, or the azure 

 color of the ocean or sky. 



Eudiom'eter (Gr. eudia, calm air, and metron, measure). — 

 An instrument for ascertaining the purity of the atmos- 

 phere, or rather the (piantity of oxygen contained in any 

 given bulk of elastic fluid. 



Hydrometeororogy (Gr. hudor, water, meteoros, a meteor, and 

 (o;/')s, discourse). — That branch of meteorology which re- 

 lates to water in the atmosphere, as rain, clouds, etc. 



Hyetog'raphy (Gr. huetos, rain, and graplio, I write). — The 

 sciciu'o of the geographical distribution of rain. 



Hygrometer, Hy'groscope (Gr. hugros, moist, and metron, 

 measure). — An instrument for measuring the degree of 

 ninisture in the atmo.sphere. 



Hygrom'etry (Gr. hugros, moist, and metron, measure). — That 

 part of physics which concerns the measurement of the 

 dryness or humidity of the atmosphere. 



Manometer (Gr. manos, rare, and metron, measure). — An in- 

 strument for mea.suring the density of the air, or other 

 elastic fluid, or rather its elastic force, to which the density 

 is supposed to be proportional. 



Manos'copy (Gr. manos, rare, and sJwpco, I view). — The 

 seienec of the determination of the density of vapors and 

 gases. 



Meteorol'ogy (Gr. meteoros, a heavenly body, and logos, dis- 

 course). — The science which treats of the atmosphere and 



