INDEX. 363 



tion, 77, 78. — Plants which absorb the largest proportion of it, 83, 

 84. — Its action upon fruits, 85, 



Plaster, employment of it as a manure, 72, 73. — Its composition, 73. 



— Use of crude and baked plaster compared, 74. — Its effects, ibid. 



— To what its action is to be attributed, ibid, et seq. — Its solubility 

 in water, 75. — Its influence upon the quality of salts, 69. 



Potash, how extracted; its use, 168, 171, 172. — Table of the re- 

 sults obtained by its extraction from different vegetables, 171. — Its 

 analysis, 173 et seq. 



PouDRETTE, its good effccts as a manure, 63. 



Preservation, causes which afiect the deterioration of animal and 

 vegetable substances, 182. — Means of preserving them, 183. 



Prizes, should be offered for the encouragement and furtherance of 

 agricultural science, 234 et seq. 



QwASS, a drink, 280- 



Resins, 147. — Sap of trees, ibid. — Means of obtaining them, 148. — 

 Their uses, 148, 149. 



Roads, district, necessity of a law relating to them, xxiv. 



Roots, one of the organs of nutrition of plants, 80. — Juices and salts 

 which they draw from the earth, ibid. — Portion of oxygen which 

 they absorb, 84, — Absorb the oxygen which exists in water, 84, 85- 



S. 



Salting, a means of preserving meats, 202. — Different methods, 203, 

 204. — Salting of butter, 206. 



Salts, their influence upon vegetation, 41. — Their chymical action, 

 ibid. — Means of knowing the quantity of them in soils, 48. — Prop- 

 erties and characteristics of nitre, of marine salt, of sulphate of soda, 

 48, 49. — Absorption of them by plants, 66, 68. — Abundant in herba- 

 ceous plants, 98, 99. — Suitable to argillaceous soils, 110. — Those 

 most common in vegetables, 175. — Those most proper for salting, 

 202. ^- Disastrous tax on salt, xxviii. 



Sap, influence of temperature upon it, 104, 105. — Its elaboration in 

 vegetables, 134. — Use made of it in various countries for making 

 drinks, 279. 



Shsspfolds, 286. 



