Index. 



Venus, particulars concerning this planet, i. 306. (See also 

 29010295. 304,305.) important points ascertained by 

 two of her transits, 298 to 303. 



Vessels used in chemistry, advantages and disadvantages of 

 those made of different materials, ii. 103 to 105 forms 

 of vessels for different purposes, 107 to 111. 



Vesta, some particulars concerning this newly-discovered 

 planet, i.305, 306. 



Vis inertiae of matter, this principle explained, i. 217- 220. 



Vision, how performed, i. 146 lecture on, 178 structure 

 of the eye, 179 manner in which vision is performed, 

 180 effects of the angle of vision, 184 causes of dis- 

 tinct and indistinct vision, 186 illustration of weak 

 and of short sight, ib. remedy for each of these affec- 

 tions, 187. 



Vitrification, what so called, ii. 68. 



Volatile oils, nature of, ii. 219. 



Volatility, meaning of the term, ii. 76, 



W. 



Water not altogether incompressible, i. 35 why rises to 

 its level, 37. 48 why raised only 33 feet by the com- 

 mon pump, 57 reason why it suddenly swells in freez- 

 ing, ii. 58 cause of the danger of throwing water into 

 boiling oils, or melted metals, 75 method of giving it 

 a degree of heat equal to that of red-hot metals, 76, 77 

 ---degree at which it boils in vacuo, 77 effect of throw- 

 ing it into a red-hot iron vessel, ib. cause why it docs 

 not become hotter by being boiled long, 78 chemical 

 lecture on water, 254. See also Hydrostatics, Hydrau- 

 lics, and Mineral Waters. 



Water-spouts, cause of, i. 91, 92 artificial, how made, 

 92. 



Wax, chemical, remarks on, ii. 282. 



Wedge, principles of this mechanic power, and its mode 

 of acting, i. 243. 



Wheel and axle, principles of this mechanic power, and 

 its mode of acting, i. 238. 



Whirlwinds, dreadful effects of in'tropical countries, i. gl. 



White, experiments to show that "this is only a compound 

 of all the colours, i. 203. 



