psycho zoic (sikozoik)

[ + μέτρον, a measure.] An instrument for de term in ing the tension of the aqueous vapor IMG:content-1235.jpg:[blocks in formation] in the air or the relative humidity. consists of two thermometers, commonly called the dry - bulb and the wet - bulb. The dry-bulb thermome ter gives the temperature of the air. The wet-bulb thermometer, whose bulb is covered with muslin wetted at the time of ob servation, cools below the קוו IMG:content-1236.jpg:[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small] cates is known as IMG:content-1237.jpg:[blocks in formation] air-temperature, and ind i the temperature of evaporation. From the com bined readings of the two thermometers, along with IMG:content-1238.jpg:[blocks in formation] that of the barometer at the time, the pre ure of the vapor in the air is obtained by means of an empirical formula, or more conveniently from specially constructed tables. psychrometric (sīkrō-met'rik), a. [ metrical. IMG:content-1239.jpg:[ocr errors] Psychrometer. psychrometrical (sī-kro-met'ri-kal), a. [ Psykter in red-figured pottery style of the artist Euthymides, 5th century, В. С. ptarmigan брак-), a white blister on the tip of the tongue, feigned to be caused by one's telling a lie, ported on a tripod. See cut in preceding column. Psylla (sil'ä), n. [NL. (Geoffroy, 1764), Pear-tree Flea-louse ( Psylla pyri). (Cro shows natural size.) scutum, and strongly developed scutellum, the body smooth, naked, or finely pilose, and the extreme tip of the wing falling between the radius and the fourth vein. It is a large group, represented in all parts of the world. P. pyri is a common pest of the pear in Europe and North America, producing two or more summer generations of naked young. From the damage it does to young blo oms in the spring, it is sometimes called the bud - blight insect, though more commonly known as the flea - louse of the pear. Psyllidæ (sil'i-dē), n.pl. [NL. (Latreille, 1807), pt. An abbreviation ( a ) of part; (b) of pint. Pt. The chemical symbol of platinum. Ptæroxylon (tē-rok'si-lon), n. [NL. (Ecklon and Zeyher, 1834), so called in allusion to the effect on those working with its wood;