248 
INDEX. 
Heat necessary to turn water into 
vapour, 96. 
of the sun, 32. 
work done by, 46. 
imprisoned in coal, 47. 
of our bodies, 46. 
Helpfulness, mutual, of insects 
and flowers, 242. 
Herschel, Sir J., on the sun, 32. 
Hive-bee, forming cells, 207. 
Hives, ventilation of, 216. 
bees cementing cracks in, 
204. 
Hoar-frost, 94. 
Honey, carried by bee, 208. 
secreted by flowers for bees, 
222. 
use of, to the primrose, 171 
Honeysuckle, scent at night, 225. 
Hooker, Sir J., on rainfall, 83. 
Horse-tails and calamites, 185. 
Huber on bees, 202. 
Huxley, Mr., on coral, 21. 
cited, in. 
Huyghens on light, 34. 
ICE, formed of pressed snow, 97. 
purity of, 98. 
sculpturing power of, 124. 
water-flowers in, 95. 
Icebergs, 98. 
Imagination in science, 7. 
Indian Ocean, vapour carried up 
from, 80. 
Insects attracted by scent and 
colour, 224. 
buzzing of, 152. 
visiting the primrose, 171. 
Iron, use of, in leaves, 161. 
Iron worked in Sussex, 197. 
Ives, Lieut., on Canons, 117. 
JAR, resonance in a, 149. 
Judd, Professor, cited, 178. 
KENTUCKY, Mammoth Cave of, 
121. 
Kettle, crust in a, 112. 
vapour rising from a, 78. 
Khasia Hills, rain in, 83. 
LACE, photographed during lec- 
ture, 48. 
Lake-district, rain in the, 84. 
Land-breeze and sea-breeze, 73. 
Landslips, 109. 
Lamium album, 230. 
Larva of bees, 210. 
Laws of nature, 24. 
Leather wetted, lifting a weight, 
65- 
Leaves, oxygen-bubbles rising 
from, 162. 
stomates in, 165. 
the stomach of a plant, 165. 
Lepidodendrons, trees of coal, 
181, 183, 185. 
Life of a plant, 173. 
Light, coloured spectrum of, 39. 
dark and light bands of, 37. 
of the sun, 31. 
effect of, on plants, 45. 
reflection of, 43. 
scattered by particles in air, 
74- 
Light-waves entering the eye, 39. 
size of, 38. 
Lightning, 55, 75. 
