xii CONTENTS. 



99, and of lessoning evils of too much dryness and moisture, 99. Lime a necessary food 

 for plants, but only within narrow limitation, 100, 101. Proportions of lime in ashes of 

 various plants, 102. 



CHAP. IX. Action of caustic lime as manure. 



Davy's theory of liming stated, 103. Applied to practice, 104. Action of caustic lime gene- 

 rally to te avoided, 104. Lime acts generally as carbonate, 105. form of classification of 

 manures, 106. 



CHAP. X. Introductory and general observations on marl and lime. 



Fossil shells, improperly called marl, 107. Incorrect use of terms in England, 108-9. Dif- 

 ferent and general misapplications of the name of " marl" (note), 109, and of " marling 3 ' 

 (note), 110. "Liming," in practice, equivalent to marling, 110 to 113. Preliminary 

 remarks on experiments, 114. Oldest applications of marl in Virginia, 114. 



CHAP. XI. Experiments ivith, and effects of, calcareous manures on acid 

 sandy soils, newly cleared. 



Experiments stated, and earliest and later results on light and acid loam, recently brought 

 mnder cultivation, 116 to 122. Errors in the mode of experimenting stated, 122-4. 



CHAP. XII. Effects of calcareous mamires on acid clay (or stiff) soils 

 recently cleared. 



Description of the peculiar soil operated on, 124. Experiments and results stated, 125 to 

 129. Remarkable effects on clover and grain crops, 127 to 129. 



CHAP. XIII. The effects of calcareous manures on acid soils reduced by 



cultivation. 



Marling always effective on such soils, 130. Experiments stated, and early good results, 130 

 to 136. Diseased crops of grain caused by excessive marling, 133. Effects of marl with 

 putrcscent manure, 137, 138. 



CHAP. XIV. Effects of calcareous manures on " free light land." 



Character of such soil, 139. Experiments, 139, 140. 



CHAP. XV. Effects of calcareous manures on exhausted acid soils, under 



their second growth of trees. 

 Experiments of this kind, 141, 142. 



CHAP. XVI. Effects of calcareous manures alone, or icith gypsum, on 

 calcareous and neutral soils. 



Inefficiency of marl on such soils, 143. Gypseous marl, 144. Experiments, 145 to 147. 



CHAP. XVII. Digression to the theory of the action of gypsum as ma- 

 nure. Supposed cause of its want of power and value on acid soils. 



General inefficiency of gypsum on Atlantic coast, and mistaken views as to the cause. 147. 

 Exceptions on neutral soils, 148. And the true cause of usual inefficiency, 149. Theory 

 of this inefficiency, and its removal, 151 to 154. 



CHAP. XVIII. The damage caused by too heavy dressings of calcareous 

 manure, and the remedy. 



Earliest effects observed, and symptoms described, 155. Means for preventing or of curing 

 the injury, 156-7. The disease found only on soils naturally acid, 157 ; and not caused 

 merely by excess of calcareous earth, 158, and probably by humate of lime, 159. 



CHAP. XIX. Recapitulation and more full statements of the effects of 

 calcareous manures. 



The results of marling have conformed to previous theoretical views, 159. Exceptions above 

 the granite range, and causes, 161. Hazel loam, 161. Effects of calcareous manure pro- 

 portioned to the organic matter in soil, 162. Marl on "galls," 163. Prevents the washing 

 effects by rains, and the moving of sandy soils by winds, 164. Quantities of marl to le 

 applied, 166. Effects in preserving vegetable matter from waste, 167. " Free light land," 

 and its speedy exhaustion, 168. Marling deepens soils, 169. Gives peculiar value to sandy 

 sub-soils, 170. Hastens maturing of crops cotton wheat, 170. Strengthens straw of 

 wheat, 171. Peculiar benefits to leguminous plants, and especially to clover, 172, and to 

 some bad weeds, 173. Failures of clover on marled lands, 173. Effect of calxiug in eradicat- 

 ing acid plants, 174-5. 



