i 238 
INDEX. 
ADELSBERO STALACTITE GROTTO, 
116 
Aerial ocean, 51, 70 
AgassLz on "erratic blocks," 122 
Air, bad, in close rooms, 54 
carrying water-vapour, 74, 78, 
93 
elasticity of, 57 
its pressure on the earth, 60 
made of two gases, 52 
rising of hot, 68 
weight of, 58 
Air-atoms forming waves of sound, 
130 
Air-bubbles bursting in waves, 143 
Air-currents, cause of, 67 
Albuminoids, 154, 160 
Almond-seed, 153 
Alum Bay Chine, 109 
Ammonia in air, 55 
Anaxagoras on size of the ran, 29 
Antarctic Continent, snowfields of, 
93 
Anthers of stamens, 164 
bursting of, 166 
Aqueous vapour, whence it comes, 
77 
Arbroath, waste of cliffs at, 117 
Ariel's song, 5 
Atmosphere causing the spread of 
light, 71 
Atmosphere, height of, 59 
weight of, 60-66 
Aurora borcalis, 52, 71 
Avalanche, noise of, 147 
BALLOON ASCENTS, 58 
Balls illustrating sound-waves, 1 29 
Barometer and its action, 64-66 
Bee-bread, 202 
Bee, pollen-masses on head of, 233 
Bees xnd flowers useful to each 
other, 235 
and orchids, 231 
cementing dead bodies, 210 
feeding of, 203, 205 
Huber on, 195 
length of life of, 210 
nursing, 199 
sentinel, 209 
swarming, 196, 206, 207 
ventilating, 209 
visit one set of flowers at a 
time, 214, 224 
worker, queen, and drone, 197 
young princess, 205 
Beetles, timber-boring, 148 
Biot, Professor, on sound in tubes, 
13* 
Bird's-foot trefoil, structure of, 229 
Birds, trill of, 148 
Bischof, on lime in River Rhine, 106 
