GLOSSARY. 



201 



which a body exerts vertically 

 downwards in consequence of the 

 action of gravity. 



Weld (Germ, wellen, to join). To 

 unite two or more pieces, generally 

 of iron, by hammering them to- 

 gether when heated. 



Whirlpool (Whirl and pool). A 

 body of water running round in a 

 circle. 



Whirlwind (Whirl and wind). A 



body of air moving in a circular or 

 spiral form, as if round an axis, 

 at the game time having a pro- 

 gressive motion. 



Woulfe's Apparatus. In chemistry, 

 a bottle with two or more openings, 

 used for generating gases. 



Wormian Bones. The small trian- 

 gular pieces of bone sometimes 

 found lying between the other bones 

 of the skull. 



Xan'thic (Gr. ai/0os, xan'thos, yel- 

 low). Of, or belonging to yellow : 

 yellowish ; having yellow as the 

 type. 



Xan'thogen (Gr. |cw0os, xan'thos, 

 yellow ; yevvaca, genna'o, I pro- 

 duce). Yellow colouring matter in 

 vegetables. 



Xan'thophylle (Gr. |ai/0os, xan'thos, 

 yellow ; </>uAAov, phullon, a leaf). 

 Yellow colouring matter in plants. 



Xan'thous (Gr. ^avQos, xan'thos, yel- 

 low). A term applied by Dr. 

 Prichard to the variety of mankind 

 including individuals with brown, 

 yellow, or red hair. 



Xiph'oid (Gr. tiQos, xiph'os, a sword; 



6t'8os, eidos, shape). Shaped like 

 a sword. 



Xiphosu'ra (Gr. j</>os, xiph'os, a 

 sword ; ovpa, ou'ra, a tail). A 

 family of crustaceous animals with 

 sword-shaped tails. 



Xylo- (Gr. }-v\ov, xulon, wood). A 

 prefix in compound words, denoting 

 relation to wood, or that wood 

 enters into the composition. 



Xylocar'pous (Gr. v\ov, xulon, 

 wood ; Kapiros, Jcarpos, fruit). 

 Bearing fruit which becomes hard 

 and woody. 



Xylography (Gr. v\ov, xulon, wood ; 

 ypa^xa, graph 'o, I write). Engrav- 

 ing on wood. 



Z. 



Zen'ith. The point in the arch of 

 the heavens which is vertically 

 above the head of the spectator. 



Zen'ith. Distance. The distance of a 

 heavenly body from the zenith, 

 measured on the vertical circle 

 passing through the zenith and the 

 body. 



Zen'ith Sector. An instrument for 

 measuring the zenith distances of 

 stars which pass near the zenith. 



Zenogxaph'ic (Gr. ZTJVOS, Zenos, a 

 genitive case of Zeus, Zeus, Jupi- 

 ter ; 7pa</>o>, graph! o, I write). Re- 

 lating to a description of the planet 

 Jupiter, or characteristic of the 

 appearance of this planet. 



Ze'olite (Gr. ew, I boil : \t6os, 

 lith'os, a stone). A term applied 

 in chemistry to certain compounds, 

 from their frothing when heated 

 before the blow-pipe. 



Zero (Italian, nothing). The point 

 of a thermometer from which it is 

 graduated : in the Centigrade and 

 Reaumur's, it is the freezing point 

 of water ; in Fahrenheit's, thirty- 

 two degrees below the freezing- 

 point. 



Zeug'ma (Gr. frvyvvfu, zeugnu'm-i, 

 I join). In grammar, a figure by 

 which an adjective or verb that 

 agrees with a nearer word, is also 

 referred to another more remote. 



