444 



INDEX, 



Barometer, water, 172 



wheA-l, ITl 



how indicates weather changes, 



1T3 



how used for measuring heights, 



1T3 



Batteries, thermo-electric, 417 



Battery, Daniull's, 4UT 



galvanic, 401 



trrove's galvanic, construction of, 

 4U(> 

 imperfections of, 407 

 luminous effects of, 410 

 Smee's galvanic, 401) 

 sulphate of copper, 406 

 trough, described, 4o5 

 Beam, rectangular, strength of, 116 



bent in the middle, why liable to 



break, 119 

 or bar, when the strongest, 115 

 Bellows, hydrostatic, 1J9 

 Bells, electrical, 3S5 

 Belts, motion communicated by, 101 

 Billiards, principles of the game of, 72 

 Blanket, utility of the nap of, 219 

 Blower, use of, '262 



Boats, life, how preventeil from sinking, 147 

 Bodies, form of, how dependent on heat, 228 

 form of, how changed by centrifu- 

 gal force, 83 

 falling, laws of, 5.5 



force and velocity depend on 

 what, 54 

 lighter than water, specific gravity, 



how determined, 39 

 non-lumiuous, when rendered viii- 



ble, 301 

 when heavy and light, 33 

 when transparent, 294 

 when luminous, 294 

 when appear white, 301 

 when solid, liquid, or gaseous, 24 

 when float in air, 185 

 Body, what is a, 11 



when called hot, 206 



size of, how affects its strength, 115 



when stands most firmly, 50 



when rolls, and when slides down a 



slope, 51 

 where will have no weight, 33 

 Boiling-point, depends on what, 241 



infl uence of atmospheric pres- 

 sure on, 342 

 Boiler-flue, 253 



Boilers, steam, how constructed, 256 

 essentials of, 257 

 locomotive, how constructed, 259 

 Bones of men and animals, why cylindri- 

 cal, lis 

 Boxes of a pump, 181 

 Breath, why visible in winter, 274 

 Breathing, mechanical operation of, 181 

 Breezes, land and sea, 284 

 Bridge, Britannia tubular, 118, 119 

 Brittleness, what is, 27 

 Bubble, soap, why rises in the air, 43 

 Buckets of wheels, 156 



Building, strengthof a, on what depends, 119 

 Buildings, how warmed and ventilated, 2U0 

 Buoyancy, what is, 138 

 Buruiug-glassee, 209 



Caloric, what is, 206 

 Camera obscura, o47 



portable, 360 

 Canals, how constructed, 137 



locks in, lo7 

 Cannon bursting by firing, 28 



varieties of, 77 

 Capillary Attraction, 25, 142 



illustrated, 143 

 Capstan, construction of, 100 

 Car axles, why liable to break, 28 

 Carriage, high, liable to be overturned, 50 

 Cask, tight, liquids will not flow from, 179 

 Catoptrics, 312 

 Cellars, cool in summer, warm in winter, 



why, 2'JO 

 Center of gravity in irregular bodies how 

 found, 4S 

 when at rest, 46 

 in what three ways sup- 

 ported, 47 

 Centripetal Farce, 79 

 Champagne, why sparkles, 181 

 Charcoal marks, why stick to a wall, 25 



why black, 301 

 Chemistry, definition of, 9 

 Children, why difficult to learn to walk, 52 

 Chimney, draught of, 202 



how constructed, 262 

 how quickens ascent of hot air, 

 202 

 Chimneys, when smoke, 262 

 Chord in music, 196 

 Chain-pump, construction of, 160 

 Climate, what is, 207 

 Circuit, galvanic, 401 

 Clock, common, described, 58 

 water, principle of, 151 

 Clocks, why go faster iu winter than in sum, 



m.T, 60 

 Clothing, when warm and when cool, 220 

 Clouds, average height of, 274 

 cirrus, 275 

 cumulus, 275 

 how differ from fog, 273 

 how formed, 274 

 nimbus, 277 

 stratus, 277 

 variety of, 275 

 what are, 273 



why appear red at sunset, 337 

 why float in the atmosphere, 274 

 Coals, meclianical force of, 251 

 Coal, equivalent to active power of man, 251 

 Co.^s on wheels, 101 

 Cohesion defined, 25 

 Cold, greatest artificial, 211 

 natural, 211 

 what is, 206 

 Color and music, analogy between, 338 

 Color, no effect on radiation of heat, 223 



origin of, 320 

 Colors, complementary, 331 



dark, absorb any heat, 225 



how affect their relative appearance, 



332 

 of natural objects on what depend, 



3:;o 

 Bimple, what are, 323 



