Index. 



315 



Winds, their causes and different kinds explained, i. 84. 



()2 various causes of, 87 velocity of the wind, 88. 

 Winter. See Summer. 

 Wood of plants, observations on, ii. 283. 



Y. 



Year, difference between a solar and a sideral, i. 



280 its correct period, ii. 14, 15. 

 Yttria, account of this kind of earths, ii. 196, 197. 



Z. 



Zinc, chemical properties of. ii. 253. 



Zirconia, account of this kind of earths, ii. 197. 



Zodiac, the twelve signs of the, i. 25Q present difference 



between their nominal and real places, 274. 

 Zodiacal light, phenomenon of, explained, i. 282 to 285. 



THE END. 



