172 DICTIONARY OF AVIATION
3. [also spelt 'plane] a flying-machine whose sustaining*
structures are planes or aeroplanes; an aeroplane flyer; an
aeroplane. plane pi,een adj. such that every straight line joining any
two points in it lies wholly in it; flat; level. plane pteen intr. drive an aeroplane flying-machine ; move
in a flyer : as, he *planed gently downward to earth. plane-dropper 'pi,een,drop3 n. a device invented by S. P.
Langley of Washington, D. C, for studying the aeroplane
when allowd to drop or fall under the influence of gravity
against the aerodynamic resistance cncounterd in its, flight. plane-spar 'pteei^spazz . one of the spars, sticks, or
poles forming the framework of an aeroplane supporting?
surface; the front or rear longitudinal beam of a main
plane of an aeroplane flyer.
planetary 'ptseni,tezi adj. of the planet or earth planetary circulation, see under circulation, planetary wind, see under wind. plan-form 'ptsei^f :zm n. a form of plan ; the plan or shape
(of a wing or other aerofoil) as projected on a horizontal
or vertical plane. planophore 'ptsena/foz n. [also spelt planofore'] a flying-
model produced by A. Penaud in 1871. plan- view 'pz.aen,viou n. the view or aspect of the plan of
an aerofoil. pluma 'p^cm-ma n. [plural pluinac, plnmas} a contour-f ether
of a bird; a penna. plumage 'ptuu-mids n. the f ethers of a bird, collectivly; the
natural covering of a bird; the ptilosis. plunge pz.And5 intr. throw or hurl itself downward thru the
air; dive hedforemost; fall or sink hedfirst in a rapid or
erratic manner : as, to soar and *plunge. pluviograph 'p;Luu-vi,gza:f n. [also spelt pluviograf] an in-
stument for recording rainfall. pneumatics njo'msetiks n. the science of .air and other
gases. pneumotide 'njum^taid n. (fanciful} the tide or swelling
current of the air; the flood of the airy ocean. pocky 'poki adj. having pocks or pock-marks, as mammato-
cumulus cloud. pogonip 'poga-nip n. a frozen fog which forms in cold air
of the high mountain-valleys of Colorado, Idaho, and Ne- vada, and which, if inhaled, is apt to cause pulmonary
trouble. pogonium p3'goo-m~9m n. the vane or web of a bird's fethcr
on either side of the shaft; the vexillum.
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