CONTENTS. Vll 



SECT. II. Atmospheric Moisture, considered with reference to Horti- 

 culture continued. PAOE 



258. Absorbent function. 259. A strict attention to the atmosphere. 

 260. Tropical plants. 261. The heat of the glass of a hothouse at 

 night. 262. The skilful balancing of the temperature and moisture. 



SECT. III. The Agitation of the Atmosphere considered with refer- 

 ence to Horticulture ....... 83 



263. Motion. 264. Perspiration. 265. Shelter. 266. Agitation 

 of the air in plant structures. 267. To heat the air before it is admitted 

 among the plants. 268. Effect on the human feelings. 269. The im- 

 pression of an atmosphere saturated with moisture. 270. Mr. Penn's 

 method of warming and ventilating. 271. Heating by pipes in the 

 ordinary manner. 272. Greenhouses. 273. Pits and cucumber-frames. 

 274. Change of air and ventilation. 275. The climate, during the 

 growing season. 276. Ventilators. 277. General principle. 



SECT. IV. Light, considered with reference to Horticulture . . 89 



279. Light follows the same laws as heat. 280. Radiation of light. 

 281. Transmitted. 282. Refracted. 283. Disperses. 284. Perpen- 

 dicular light. 285. The efficiency of light. 286. A due proportion 

 between light and heat. 287. Absence of light. 



CHAPTER V. 



WORMS, SNAILS, SLUGS, REPTILES, BIRDS, &c., CONSIDERED WITH 



REFERENCE TO HORTICULTURE . . . . .93 



SECT. I. The Earth-worm, considered with reference to Horticulture 94 



290. Lumbricus terrestris. 293. Natural uses. 294. Injury. 

 SECT. II. Snails and . Slugs, considered with reference to Horticulture 96 



297. Helix asp^rsa, and H. nemoralis. 298. Slugs. 299. Snails 

 and slugs. 300. Snails and slugs are hermaphrodite and oviparous. 

 301. Natural uses of the snail. 302. Retires. 303. To destroy snails. 

 304. To destroy slugs. 



SECT. III. Insects, considered with reference to Horticulture . . 99 

 SUBSECT. I Of the Nature of Insects, and their Classification . .99 



306. Insects. 307. Winged insects. 308. Insects without wings. 

 309. Crabs and spiders. 310. Arrangement here given. 



SUBSECT. II. Transformation of Insects 101 



311. Eggs. 312. Larvae. 313. Nymphae or pupse. 314. Perfect 

 insect. 



SUBSECT. III. Food of Insects 102 



315. Nourishment. 316. Roots, stem, and branches. 317. Fo- 

 liage. 318. Flowers. 319. Number. 320. Food. 322. Transforma- 

 tion. 323. Gluttonous. 324. No nourishment. 325. Eat . . 



SUBSECT. IV. Distribution and Habits of Insects . . . .104 



326. Distribution. 327. Water. 328. Land insects. 329. Other 

 animals. 



SUBSECT. V. Uses of Insects 105 



332. Uses. 333. Medicine. 334. Insects destroyed by other in- 

 sects. 335. Consume dead animal substances. 

 SUBSECT. VI. Means contrived by Nature to limit the Multiplication 



of insects 105 



336. Continued rain. 337. Late frosts. 338. Inundations. 339. 

 Enemies. 340. Insectivorous Mammalia. 341. Birds. 342. Wood- 



