X AN 



X AN 



on a pivot at each extremity of its axis, 

 or upon a pivot at one extremity only. 

 The winch or crank, by which the barrel 

 is turned, is moved round by the hand, 

 and there is no diiference in the principle 

 whether a whole wheel is turned, or a 

 single spoke. The winch, therefore, an- 

 swers to the wheel, while the rope is 

 taken up, and the weight raised by the 

 axle. 



WINE. The name given by chemists 

 to all liquors which have become spiritu- 

 ous by fermentation. 



WINE TEST. A reagent for detect- 

 ing the presence of lead in wine, by con- 

 verting the acid into a salt of lead. That 

 which is usually sold is made by dis- 

 solving half an ounce of sulphuret of 

 arsenic, and one ounce of lime, in half a 

 pint of distilled water, and filtering the 

 solution. 



WINTERACEiE. The Winter's Bark 

 tribe of Dicotyledonous plants. Trees or 

 shrubs, with leaves alternate; flowers 

 hermaphrodite or unisexual ; stamens 

 hypogynous ; fruit consisting of a single 

 row of carpella. 



WI'THAMITE. A mineral found at 

 Glencoe in Scotland, and regarded as a 

 variety of epidote. 



WI'THERITE. Carbonate of baryta, 

 or rhomboidal baryta, found in Cumber- 

 land and Durham in lead veins traversing 

 a secondary limestone, which rests on 

 red sandstone. 



WOLFRAM. Tungstate of iron and 

 manganese, occurring, massive and crys- 

 tallized, in Bohemia and other countries ; 

 also in the form of octohedral supposi- 

 titious crystals, derived from tungstate of 

 lime. 



WO'LKONSKOIT. An emerald-green 

 mineral, containing oxide of chromium, 

 iron, silica, and magnesia, and found at 

 Perm in Russia. 



WO'LLASTONITE. Table spar; a 

 silicate of lime, found at Mount Vesu- 

 vius, at Nagyag, &c. 



WO'LNYNE. A variety of sulphate 

 of baryta found at Muzsay in Hungary. [ 



WOOD, ROCK. Mountain wood. A 

 variety of asbestus, usually massive, of a 

 brown colour, and having the aspect of 

 wood. 



WOOD-OPAL. Opalized wood; one 

 of the varieties of opal, occurring in vari- 

 ous vegetable forms. 



WOOD-STONE. The name given by 

 Werner to specimens of wood which have 

 been converted into hornstone, a silice- 

 ous substance sometimes approaching to 

 flint or common quartz. 



WOOD-TIN. The name given by 

 Werner to one of his divisions of oxide of 

 tin or tin-stone; a variety of which, com- 

 posed of radiated-fibrous small globules, 

 and marked with concentrically-disposed 

 brown and yellow colours, is called toad's 

 eye wood-tin. 



WOODY TISSUE. Pleurenchyma. 

 Elongated cells, tapering to each end, 

 and constituting the elementary struc- 

 ture of wood. 



WOORALY. A celebrated poison, 

 also called woorari, ourari, or urari, pro- 

 duced by the Strychnos toxifera of 

 Guayana. 



WOOTZ. Indian steel; supposed to 

 be an alloy of steel with small quantities 

 of silicium and aluminum. 



WOULFE'S APPARATUS. A series 

 of two or three-necked bottles, connected 

 together by intermediate tubes, used for 

 impregnating water with carbonic and 

 other gases. 



WREDE'S EXPERIMENT. An ex- 

 periment instituted by Von Wrede for 

 measuring the velocity with which heat 

 is propagated. By means of a thermo- 

 electric calorimeter, placed in a telescope, 

 it was found that the temperature of the 

 eastern edge of the sun's image exceeded 

 that of the western edge, and conse- 

 quently the velocity of the rays of heat 

 was less than that of the luminous rays. 

 The rate of the velocity of heat radiated 

 from the sun is only |ths the velocity 

 of light, or about 163,600 miles in a 

 second. 



'^m^oh i^^^Mi^ 



XANTHIC AND CYANIC SERIES. 

 Botanists have divided flowers into two 

 great series, with reference to their co- 

 lours, viz. those having yellow for their 

 type, and which are capable of passing 

 379 



into red or white, but never into blue; 

 and those of which blue is the type, 

 which can pass into red or white, but 

 never into yellow. The former series is 

 termed, by some writers, oxidised, and 



