INDEX. 



Balusters, what are, 45 

 Balloon, why rises in the air, 13 

 Bark, how especially adapted as a cover- 

 ing for trees, 157 

 Barometer, construction of, 102, 103 



heat and cold no effect on, 113 

 how differs from a thermo- 

 meter, 104 



how invented, 101, 102 

 tube, why left open, 104 



iBuilding, properties of a good, 41 

 Buildings, principle of warming and von- 



t ; latins, 204 



Burning'point, what is, 222 

 Burns on the skin affect respiration, 235 



Calomel, what Is, 310 



use of, for determining the Caloric, meaning of term, 181 



state of the weather, 

 Base of a column, 46 

 Battery, galvanic, 291 



/oles of, 292 

 in "~ 



Beams, strength 



different positions. 



Bed coverings, the warmest, 213 



india-rubber, why not used Capital of a column, 46 



for, 218 



feather, safe place in a thunder storm, 

 2S3 



Candle, why burns when lighted, 281 

 Cannon, distances to which they can send 



a ball, 35 



varieties of, 35 



Capillary attraction defined, 65 



vessels, action of, 237 



what are they, 236 



Carbon, more thrown off from the system 



in winter than in summer, 240 

 what is, 224 



Carbonic acid, sources of, 212 

 gas, 206 



a poison, 207 



Beer, why turns sour, 805 



Bell, cracked, why discordant, 119 



metal, composition of, 116 



sound of, stopped by touching it, 118 where" found, 206 



Bellows, use of in kindling a fire, 229 |Cat, fur of, why sparkles in cold weather, 

 Birds, how enabled to fly, 26 278 



why stretch out their necks in fly- Cats, why see in the dark, 267 



ing, 27 

 Black, the absence of color, not a color, 



270 



why some bodies are, 270 

 Blankets, why warm, 14S 

 Blood, arterial and venous, 237 



color of, 237 



how affected by oxygen, 205 

 Blowers, of grates, &c., use of, 217 

 Boats, life, how prevented from sinking, 



Body, a, how far it can fall in one second, 



Cellars, why cool in the summer, 151 

 warm in the winter, 151 

 Cement, definition of, 38 

 Cements, hydraulic, 39 

 Centrifugal force, 23 



illustrations of, 23, 24 

 Chalybeate waters, 54 

 Champagne, why sparkles, 73 

 Charcoal, how made, 224, 225 



what is, 224 



why black, 261 

 Chemistry, familiar, 302 



28 Children, why difficult to learn to walk, 



what is a, 4 18 



Boiling point, influence of atmospheric Chimney, fire in, how extinguished, 230 



Chimneys, how quicken the ascent of hot 



air, 215 

 of manufactories, why usually 



very long, 215 

 principles of construction of, 



pressure on, 157, 1S8 

 of a 



liquid, 155 

 Bones, hollow cylinders, 37 

 Boots, why cannot a man raise himself by 

 pulling on the straps of, 23 



Bottle, why gurgles, 73 

 Bottles of ale and cider, why frequently 

 burst, 74 



216 



smoke under what circumstan- 

 ces, 216 



Bouquets, arrangement of flowers in, 273 Choke-damp, what is, 211 



Breakers, what are, 61 j Church, crowded, persons in feel drowsy, 



Breath, why visible in winter, and not in' 210 



summer, 89 Circuit, galvanic, 292 



Breathing on glass, why dulls it, 88 ! Cities, air >f, less pure than the country, 



why difficult at a very high 210 



elevation, 72 Cleanliness, necessity of, 233 



Bricks, burned, why red, 39 jClimate, meaning of the term, 104 



why used for lining stoves and fur- Climates, peculiarities of, 104 



naces, 151 temperature of, coloration pecu- 



Broth, cooled by convection, 159 liar to, 271 



Bubbles, air, in ice, origin of, 178 ' Clock, common, what is a, 29 



in a tea-cup, how attracted, 14 Clocks, why go faster in winter than ia 

 on leaves of water plants, what the summer, 30 



are they, 236 Clothing, contains no warmth in itself; 



eoap, why ascend, 56 | 152 



