DICTIONARY OF AVIATION 131
2. redily absorbing and retaining moisture : as, a *hygro- metr,ic substance, a *hygrometic plant.
liygrometrical ,hEii-gz9'met|;i-k9l adj. same meaning as hy- gromeiric.
hygrometrically ,hai-gz9'metr,ik9-li adv. in a hygrometjic manner; with respect to hygremetjy.
hygrometricity ,hai-gz3-mi'tisi-ti n. the property of being hygrometjic or of becoming moist by absorbing water from the air.
liygrometry ,hai'gzmi-tr,i n. the art of mesuring humid- ity, especially that of the atmosfere.
hygroscope 'hai-gz9,skop n. an instrument for showing the humidity of the air, as that of Saussure ; a hair hygrometer.
hygroscopy ,hai'gzosk9-pi n. the art of using or of making hygroscopes; also, the art of observing humidity^condi- tions, or of making them apparent.
hygrothermal ,hai-gz9'6B:z-m9l adj. of the humidity and temperature of the atmosfere considerd together.
hygrothermal area, an area of the earth's surface over irhich the atmosferic conditions are included within cer- tain limits as to humidity or temperature.
hyinenopter ,hai-mi'nopt9z n. any insect of the order Hy- menoptera.
hyiiienoptera ,hai-mi'nopt9-z9 n. pi. a large order of insects including the ants, wasps, and bees, having (normally) four hymeneid or membranous wings.
hyperbola ,Iiai'pB:z-b9-l9 n. [ploral hyperbolas'] a plane curv consisting of two separate equal infinit branches fermd by the intersection of a plane with both branches of a double cone.
hypopteron ,hai'pept9-z9n n. the linear fether^tjact which extends from the axilla or arm^pit outward, en the under side of a bird's wing.
hypoptilum ^lai'pepti-tem n. same meaning as hyporachis.
hyporachis ,hai-p9^ee-kis n. [also spelt hyporhachis, hypor- rhachis'} the accessory or subsidiary rachis, shaft, or plume of a bird's fether which springs from the main stem at the junction of quill and rachis; the hypeptilum; the after- shaft.
��iceberg 'ais^Bizg n. a large mass or mountain of ice detacht
from a Polar glacier and carried out to sea. ice-blink 'ais,bhr)k n. a peculiar tuhitening of the sky, low
down near the horizon, seen in the Arctic regions on ap-
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