198 RE-LIMING IN BRITAIN. 



lirne again, as if it Lad never been applied before. Elsewhere this 

 author speaks of twenty years as the ordinary duration of heavy 

 limings ; and that in some cases, on grass land, the effect lasted 

 thirty years, (p. 896.) " A heavy marling or chalking in the south- 

 ern and midland counties of England is said to last for thirty years, 

 and the same period is assigned for the sensible effects of the ordi- 

 nary doses of lime-sand in Ireland, and 9f shell-sands and marls in 

 several parts of France." (p. 396, 397.) 



There is no subject of practical agriculture on which it is more 

 difficult to gather truth from the evidence of alleged facts than in 

 regard to applications of calcareous manures, made by persons hav- 

 ing no knowledge or conception of their true action. The " facts'," 

 as understood and reported by the most truthful men, may be de- 

 ceptions, and lead to false conclusions. There is a general accord- 

 ance in the practices of the re-limings, as above described, and the 

 repetitions of my own early marlings yet how different in the 

 causes supposed in the two cases ! The British re-limings are re- 

 'quired because the first dose was supposed to be either nearly or 

 entirely gone, " and the land had reverted to its original condition, 

 destitute of lime." In the other case, the lime certainly still re- 

 mained in quantity, and was believed to be not appreciably lessened ; 

 but more was required to balance and combine with the increased 

 organic matter. Besides these two causes, supposed and real, for 

 land needing re-liming, it may be wanting, and more than one re- 

 petition, because the previous dose was much too small for the 

 then wants of the soil. And in numerous cases, when no need 

 truly exists for more lime, and when indeed the land has been 

 already limed too heavily for its condition, but is exhausted of ifei 

 organic matter, and thereby impoverished by severe tillage, still 

 more lime is sometimes ignorantly added, and uselessly for its 

 resuscitation, if not injuriously. Yet all these different cases of 

 proper and improper applications, would be confounded by ordi- 

 nary report. And all that we can be sure of from such facts 

 reported to and published by Prof. Johnston, is that re-limings, at 

 intervals of twenty or more years, are common in Britain ; and 

 that sometimes, or generally, they have done good, and sometimes 

 harm. The statements of experience rarely extend so far as to 

 include the third or fourth application. When these shall be 

 known, I predict that there will be found many cases in which the 

 last application is in excess, and will do more harm than good. 

 Yet, strictly in accordance with the views of Prof. Johnston, the 

 fourth or the hundredth application, after proper intervals, would 

 be as much needed, and therefore should be as beneficial as the 

 first. 



So much for the facts, and the very imperfect knowledge we can 



