INDEX. 361 



Grains, means of preserving them, 190. See Trenches. 



Gravel, its presence necessary in a good soil, 26. — Utility of mixing 



it with impoverished soils, 26, 27, 

 Gums, their nature, 135. — Their use in the arts, 135. — Employed as 



food, ibid, — Analysis of them, 136. 



H. 



Heat, its effect, xv. — Its influence upon bodies, 9. — Unequal propor- 

 tion of this fluid in bodies, ibid. — Phenomena produced by its emis' 

 sion and absorption, ibid. — Its effects, dilation, fluidity, motion, 11. 

 — Combustion of vegetables in large masses, 15. — Its action upon 

 the plant, 36. — Upon animals, ibid. — Different upon different soils, 

 ibid. — Developed more or less by manures, 37. — Its influence upon 

 germination, 77. — Upon vegetation, 58 et seq. 



Horns, their effects as a manure, 60. — The advantages of employing 

 them, 76. 



Hydrogen (gas), 15. 



Hydrometer, 269. 



I. 



Implements of HusBANDRY,comparison of tillage performed with the 

 hoe, spade, and plough, 107. — Use of the harrow and roller, 108, 109. 



Indigo. See Woad. 



Instkuction, special, in agriculture ; its necessity and utility, 233 ei^cy. 



Irrigation, its use according to the nature of soils, 116. — Times most 

 favorable to it, 117. 



L. 



Lamp-black, 149. 



Laws called for by agriculture, xviii et seq. 



Leases, inconveniences resulting from their sJaiar-t duration, xzxi v. 



Leather, 158. 



Leaves, principal organs of nutrition, 35 et seq. 



Ley-washing, cleansing of fabrics of hemp, &c., 289. — An economical 

 liquor for supplying the place of soap ; mode of using it, 290. — Ap- 

 paratus for whitening household linen, 290. — Processes for whiten- 

 ing cotton thread, 290. 



Life, agricultural, preferable to a msnu&LCtunag life, 223. 



Light, one of the fluids diffused through the atmosphere, 1. — Its influ- 

 ence upon vegetation,12, 13. — Upon germination, 79. — Upon nittri- 

 tion, 81. — Necessary to the giving out of oxygen gas by leaves, 101. 



Lime, enters into the composition of arable soils, 18. — Deprives thetd^ 

 of its carbonic acid, 21. — Process for obtaining it pure ; its properties, 

 31 



