WAT 



L 459 ] 



W E A 



cations of the whole system ; from 

 these arteries it passes on through 

 the veins into the vense cavse, and 

 by them is carried into the right 

 auricle; from the right auricle it 

 passes into the right venticle, and 

 by the right ventricle is propelled 

 into the piilmonary arteries, to be 

 conveyed through the lungs, in its 

 passage through which it becomes 

 aerated, loses its dark and assumes 

 a florid colour, and is once more 

 arterial blood ; it then passes into 

 the pulmonary veins, and is con- 

 veyed into the left auricle, whence 

 it is forced into the left ventricle, 

 and once more into the aorta. 



WA'TER. (wasser, Germ.) When 

 pure, water is transparent, and 

 destitute of colour, taste and smell. 

 The specific gravity of water is 

 always supposed = 1*000, and it 

 is made the measure of the specific 

 gravity of all other bodies. When 

 water is cooled down to 32 Fah. 

 it assumes the form of ice. When 

 heated to the temperature of 212 

 Fah. it boils, and is converted into 

 steam. Pure water consists of 

 two parts of hydrogen and one of 

 oxygen. 



WA'VED. Variegated; undated. 



1. In botany, applied to the mar- 

 gins of leaves, when bordered alter- 

 nately with numerous minute seg- 

 ments of circles and angles. 



2. In entomology, applied to insects 

 when the margin of the body is 

 marked with a succession of arched 

 incisions. 



WA'VELLITE. A rare mineral, first 

 discovered in Devonshire by Dr. 

 Wavell, and named after him. Its 

 colours are either pure white or 

 white tinged with grey, green, or 

 yellow ; lustre silky. Specific gra- 

 vity from 2-25 to 2'70. It consists 

 essentially of alumine, being com- 

 posed of alumine 71 '5, water 28*0, 

 oxide of iron 0'5. Sometimes a 

 trace of silex and lime is present, 

 and Sir H. Davy discovered in 



Wavellite the presence of fluoric 

 acid. 



WEALD, (from wold, Germ, a wood.) 

 The name given to a valley, or 

 tract of country, lying between the 

 North and South Downs of Kent 

 and Sussex. In some of the older 

 publications the Weald is called 

 the Wild. At the close of his 

 account of the organic remains of 

 Tilgate Forest, Dr. Mantell says, 

 "it may be remarked that the 

 vast preponderance of the land and 

 freshwater exuvia3 over those of 

 marine origin, observable in these 

 strata, warrants the conclusion that 

 the Hastings or Wealden beds were 

 formed by a very different agent 

 from that which effected the depo- 

 sition of the Portland limestone 

 below, and the sands and chalk 

 above them. Whether the land of 

 that time were an island or a con- 

 tinent, may not be determined ; 

 but that it was diversified by hill 

 and valley, and enjoyed a climate 

 of a higher temperature than any 

 part of modern Europe, is more 

 than probable. Several kinds of 

 ferns appear to have constituted 

 the immediate vegetable clothing 

 of the soil. But the loftier vege- 

 tables were so entirely distinct from 

 any that are now known to exist 

 in European countries, that we 

 seek in vain for anything at all 

 analogous, without the tropics. The 

 forests of Clathraria and Endogenitae 

 (the stems of which, like some of 

 the recent arborescent ferns, pro- 

 bably attained a height of thirty or 

 forty feet,) must have borne a much 

 greater resemblance to those of tro- 

 pical regions, than to any that now 

 occur in temperate climates. Turtles 

 of various kinds must have been 

 seen on the banks of its rivers and 

 lakes, and groups of enormous cro- 

 codiles, basking in the fens and 

 shallows. The gigantic Megalo- 

 saurus, and yet more gigantic Igu- 

 anodon, must have been of such 



