COSTS OP ACTUAL M ABLINGS. 229 



might not exceed 10 per cent, per annum, on the cost (though I 

 have never known so little, from any proper application). In the 

 latter case, of minimum expense and maximum effect of marling, 

 the net profit might be 200 per cent, per annum on the cost. Most 

 operations would be much within these extreme results. In much 

 the greater number of cases of my own labours, and of all others 

 which ' have come under my personal observation, and were con- 

 ducted and applied with ordinary judgment, the net profits have 

 not fallen short of 50 per cent, per annum on the expense, for the 

 whole time which has elapsed since the application. How long 

 such operation may continue, and whether increasing or decreasing, 

 I leave to be inferred from the preceding facts and reasoning, in 

 regard to the duration of the effects of calcareous manures. The 

 grounds of this belief have been already in part submitted, in 

 sundry statements of particular products, the results of particular 

 applications. The expenses of particular and large marling opera- 

 tions have been as carefully noted, and will hereafter be reported 

 in detail. But for the better understanding of these details, and 

 more methodical arrangement, they must be postponed until other 

 explanatory matters shall have been presented. I will therefore 

 here merely state the general results. In four extensive marling 

 operations, on three different farms, under different circumstances, 

 and nearly all of which were unusually difficult and laborious, the 

 total expenses were severally 142, 97 i, 86, and 94 cents for the 

 100 heaped bushels of marl, spread upon the fields. 



Most of marling labours, under ordinary circumstances of facility 

 and difficulty, ought not to exceed in cost $1 for the 100 bushels 

 of marl applied ; while the ordinary profits thereon will well repay 

 an expenditure of $6, under existing circumstances ; or of twice or 

 thrice as much, if lands and their permanent improvements in 

 Virginia were priced according to their producing and intrinsic 

 value, and not according to the excess of supply over demand in 

 the land market. 



The argument in support of the several propositions which were 

 advanced, and have been discussed through so many chapters, is 

 now concluded. However unskilfully, I flatter myself that it has 

 been effectually urged ; and that the general deficiency in our soils 

 of calcareous earth, the necessity of supplying it, the profit by that 

 means to be derived, and the high importance of all these consider- 

 ations, have been established too firmly to be shaken by either 

 arguments or facts. 



There remain, however, and will be presented in order, other 

 important matters ; which though not necessary for the mainten- 

 ance of the series of propositions which have been argued, and 

 which were too long to have been properly included in that discus- 

 sion, are not the less deserving of consideration. 

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