522 



PHYSICAL SCIENCES. 



WATERSPOUTS. 



process of congelation, 276 ; boil- 

 ing points of, 277 ; decomposed by 

 electric agency, 307 ; as an electric 

 conductor, 309 ; rotating by elec- 

 tricity, 314. 



Waterspouts, origin and cause of, 128. 



Waterstone, Mr., magnetic property 

 of the ethereal medium maintained 

 by, 357. 



Waves neutralized by interference, 99. 



, atmospheric, over local districts, 



periods, dimensions of, 121, 122. 



of sound, 131 ; furnishing an 



illustration of reflections of sound 

 and light, 137 ; interference of, pro- 

 ducing calm, 139. 



Wedgwood, Dr., attempts of, to trace 

 objects by means of light, 203, 204. 



Week, the, of seven days, the most 

 ancient and universal division of 

 time, 85. 



Wells, increase of temperature in, 

 230,231. 



Welsh, Mr., observations made by, in 

 a balloon ascent, 119. 



West Indies, the, cause of hurricanes 

 in, 126. 



Wheels invented to test intensity of 

 sound, 132, 133. 



Wheat, range of its cultivation, 250. 



Wheatstone, Professor, experiments in 

 acoustics of, 132 ; musical instru- 

 ments invented by, 143 ; paper on 

 musical vibrations read by, 145 ; 

 experiments on sounding boards of, 

 150 ; experiments on sound rein- 

 forced by resonance, 151 ; instru- 

 ment measuring velocities of elec- 

 tricity and light invented by, 202 ; 

 spectrum of an electric spark ob- 

 served, 289; speed of electricity 

 measured, 289, 290 ; experiments 

 on the spectrum of Voltaic flame, 

 303. 



Willis, Mr., articulating machine in- 

 vented by, 151 ; investigations of, 

 into the mechanism of the larynx, 

 152. 



Winds, trade, 122, 123-j monsoons, 

 124 ; extra-tropical, in the North 

 Atlantic, ib. ; currents above the 

 trade winds, 124, 125 ; pheno- 



ZETA. 



mena of rotatory motion, 125 ; 

 hurricanes, 125, 128 ; agency of, in- 

 fluencing temperature, 244, 245. 



Wines, range of cultivation of the 

 best, 250. 



Winter, atmospheric electricity in, 

 291. 



, mean temperature of, varying in 



the same latitude, 246, 247. 



Wolf, Professor, periods of variation 

 in solar heat computed by, 225. 



Wollaston, Dr., experiments of, on 

 sensitiveness to sound, quotation 

 from, 132 ; experiment of, to show 

 the effect of variable media on re- 

 fraction, 156 ; discovery of rayless 

 lines in the solar spectrum, 162 ; 

 observations of, on the chemical 

 properties of the solar spectrum, 

 203, 209; magnetic rotation sug- 

 gested by, 313 ; light emitted by 

 the heavenly bodies calculated, 404. 



Xi Ursae Majoris, periodic time of, 

 398 ; velocity of the revolving star, 

 400. 



YEAR, a, in Jupiter and Saturn, 66 ; 

 tropical change in its length, 80 ; 

 length of the sidereal, t'6. ; period 

 of the mean, 83 ; estimation of the 

 Egyptian, 85 ; first of our era, 86 ; 

 length of the, affected by a comet's 

 passage, 359. 



Young, Dr., his calculation of the 

 possible compression of solids, 78 ; 

 date of a horoscope determined by, 

 89 ; density of a liquid column 

 estimated by, 114; exception ad- 

 duced by, to a general law in 

 acoustics, 137 ; his theory of the 

 pleasures of harmony, 142 ; undu- 

 latory theory established by, 169 ; 

 data used by, to test his theory of 

 light, 175; illustration of, proving 

 sound and heat kindred forces, 280, 

 281. 



ZETA Cancri, a triple star, 395 ; 

 periodic time of, 398 ; revolution, 

 400 ; colours, 401. 



