MARL ON RAIL-ROADS. 317 



after making the crop, there is as much loss of crop suffered by 

 the delay, as would have paid for making the improvement. 



The objections to carrying marl unusual distances, admitted 

 above, apply merely to improvements proposed for field culture. 

 But it would be profitable, even under existing circumstances, 

 for rich marl to be carried 10 miles by land, or 200 miles by 

 water, for the purpose of being applied to gardens, or other laud 

 kept under perpetual tillage, and receiving frequent and heavy 

 coverings of putrescent manure. In such cases, independent of 

 the direct benefit which the calcareous earth might afford to the 

 crops, its power of combining with putrescent matters, and pre- 

 venting their waste, would be of the utmost importance. If the 

 soil is acid, the making it calcareous will enable half the usual 

 supplies of manure to be more effective and durable than the whole 

 had been. There are other uses for marl, about dwelling-houses 

 and in towns, which should induce its being carried much farther 

 than mere agricultural purposes would warrant. I allude to the 

 use of calcareous earth in preserving putrescent matters, and 

 thereby promoting cleanliness and health ; which subject has been 

 already discussed. 



Either lime or good marl may hereafter be profitably distributed 

 over a remote strip of poor land, by means of the railroad now 

 constructing from Petersburg to the Roanoke [1831]; provided 

 the proprietors do not imitate the over greedy policy of the legis- 

 lature of Virginia in imposing tolls on manures passing through 

 the James River canal. If there were no object whatever in view 

 but to draw the greatest possible income from tolls on canals and 

 roads, true policy would direct that all manures should pass from 

 town to country toll free. Every bushel of lime, marl, or gypsum 

 thus conveyed, would be the means of bringing back, in future 

 time, more than as much wheat or corn ; and there would be an 

 actual gain in tolls, besides the twenty-fold greater increase to the 

 wealth of individuals and the state. 

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