BRITISH OPINIONS OF LIMING. 197 



showed visible effects at the end of sixty years. Lord Kames men- 

 tions a particular case of the continued beneficial effects of an ap- 

 plication of calcareous manure for one hundred and twenty years 

 (Gentleman Farmer, p. 266, Edin. Ed.), and even Professor John- 

 ston, whose reasoning I shall have mainly to oppose, quotes, with 

 apparent assent, the opinion of "an intelligent and experienced 

 farmer," that certain lands in Scotland " would never forget an 

 application of forty to sixty bushels of lime to the acre." 



I shall take from the Lectures of Professor Johnston, the argu- 

 ment in support of the temporary continuance and operation of 

 lime in soils, and its final entire loss and disappearance. No more 

 able advocate of the opinions I shall oppose, nor one of higher au- 

 thority, could be presented. His observations on lime as manure 

 are the most recent, and fullest of any known - } and in most of the 

 points, his opinions command my approval. In regard to this 

 branch of the subject, his views are as follows : 



"A certain proportion of lime/ 7 says this author, "is indispensable 

 in our climate to the production of the greatest possible fertility. 

 Let us suppose a soil to be wholly destitute of lime the first step 

 of the improver would be to add this indispensable proportion. 

 This would necessarily be a large quantity ; and therefore, to land 

 limed for the first time, theory indicates the propriety of giving a 

 large dose. Every year, however, a certain variable proportion of 

 the lime is removed from the soil by natural causes. The effect of 

 the removal in a few years becomes sensibly apparent in the di- 

 minished productiveness of the land. After a lapse of five or six 

 years, during which it has been gradually mixing with the soil, 

 the beneficial effects of the lime are generally the most striking j 

 after this, they gradually lessen, till, at the end of a longer or short- 

 er period, the land reverts to its original condition" '(p. 383, 384.) 

 He states the usage in Roxburgh (Scotland), where most lands 

 are leased for nineteen or twenty-one years. On entering upon a 

 farm, the new tenant begins with applying 240 to 300 bushels of 

 [unslaked] quick-lime to the acre, and continues equal progress 

 with his rotation of tillage, until all the farm is limed, within the 

 time of four or five years. He then continues to crop without more 

 liming for fourteen or sixteen years ; when, if he is sure of remain- 

 ing on his farm for another lease, he begins to lime again, at the 

 same rate as before. * The author speaks of no limit to these re- 



rted heavy limings ; and therefore it may be fairly inferred, that 

 considers the repetitions, and the alternations of full supply and 

 disappearance of the lime, to be indefinite, or that at no future time 

 will such repetitions of liming cease to be required. Indeed, such 

 inference is unavoidable, if his previous statement be correct, that 

 land " reverts to its original condition," of being " wholly destitute 

 of lime." In such case, the land certainly would as much need 

 17* 



