PiLHT II. 



ON THE INORGANIC ELEMENTS OF PLANTS. 



LECTURE IX. 



INORGANIC CONSTITUENTS OP VEGBTABLE SUBSTANCES. 



Of the relative proportions of inorganic 



matter ill vegetable substances p. 178 



Kind of inorganic matter found in plants. . 180 

 Of the several elementary bodies usually 

 met with in the ash ofi)lanls 182 



Of those compounds of the inorganic ele- 

 ments which enter directly into the 

 circulation, or exist in the substance 

 and ash of plants 183 



LECTURE X. 



INORGANIC CONS'I'ITUKNTS OIV PLANTS CONTINUED, 

 Inorganic constituents of plants continued. 200 I To what extent do the crops most usual- 

 Tabular view of the constitution of tlie | ly cultivated exhaust the soii of inor- 



compounds of the inorganic elements j ganic vegetable food 7 220 



above described 214 j Of the alleged constancy of the inorganic 



On the relative proportions of the differ- constituents of plants, in kind and 



ent inorganic compounds present in quantity 225 



the ash of plants 216 | 



LECTURE XL 



NATURE AND ORIGIN OF SOILS. 



Of the organic matter in the soil 229 I On the general structure of the earth's 



General constitution of the earthy part of | crust 237 



the soil , 230 I Relative positions and peculiar charac- 



Of the classification of soils from their | ters of the several strata 239 



chemical constituents 232 j Classification of the stratified rocks, their 



Of the distinguishing characters of soils 1 extent, and the agricultural relations of 



and subsoils 235 the soils derived from them 241 



Of the general origin of soils 23tj | 



LECTURE XIL 



COMPOSITION OP THE GRANITIC ROCKS, AND OP THEIR CONSTITUENT MINERALS. 



Composition of the granitic rocks 257 I Of the occurrence of such accumulations 



Of ihe degradation of the granitic rocks, | in Great Britain, and of their influence 



and of the soils formed from them ...260 

 Of the trap rocks, and the soils formed 



from them 263 



Of supeificial accumulations of foreign 



materials, and of the means by which 



they have been transported 266 



n modifying the character of the soil.. 270 

 llow far these accumulations of drift in- 

 terfere with the general deductions of 



Agricultural Geology 272 



Of superficial accumulations of peat 275 



LECTURE XIII. 



EXACT CHEMICAL CONSTITUTION OP SOILS. 



Of the exact nature of the organic con- I Of the exact chemical constitution of 

 stituents of soils, and of the mode of | certain soils, and of the results to be 

 separating them 277 | deduced from thom 282 



Of Ihe exact chemical constitution of Of the physical properties of soils 290 



the earthy part of the soil 281 | Conclusion 297 



