110 EXPERIMENTS IN MARLING*. 



these experiments were measured when the land was ploughed for 

 wheat in October. The subsequent loss from shrinking would of 

 course be greatest on the corn from the poorest and most backward 

 land, as the most defective and unripe ears would always be there 

 found. Besides, every ear, however imperfect or rotten, was in- 

 cluded in the measurement. For these several reasons, the actual 

 increase of product on the marled land was always greater than 

 will appear from the comparison of quantities measured ; and from 

 the statements of all such early measurements, there ought to be 

 allowed a deduction, varying from 10 or 15 per cent, on the best 

 and most forward corn, to 30 or 35 per cent, on the latest and 

 most defective. Having stated the grounds of this estimate, 

 practical men can draw such conclusions as their experience may 

 direct, from the dates and amounts of the actual measurements 

 that will be reported. Some careful trials of the amount of shrink- 

 age in particular experiments will be hereafter stated. 



No grazing had been permitted on any land from which experi- 

 ments will be reported, since 1814 (or since being cleared, if in 

 forest at that time), unless the contrary shall be specially stated. 

 The cropping had also been mild, during that time, though previ- 

 ously it was the usual exhausting three-shift and grazing course. 



CHAPTER XI. 



EXPERIMENTS WITH AND EFFECTS OF CALCAREOUS MANURES ON 

 ACID SANDY SOILS, NEWLY CLEARED. 



PROPOSITION 5 continued. 



As most of the experiments on new land were made on a single 

 piece of twenty-six acres, a general description or plan of the 

 whole will enable me to be better understood, as well as to be more 

 concise, by references being made to the annexed figure. It forms 

 part of the ridge or high table land lying between James River 

 and the nearest stream running into Powell's creek. The surface 

 is nearly level, but slightly undulating. The soil in its natural 

 state very similar throughout, but the part next to the line B C 

 somewhat more sandy, and more productive in corn, than the part 

 next to A D ; and, in like manner, it is lighter along A e, than 

 nearer to D /. The whole soil, a gray sandy acid loam, not more 

 than two inches deep at first, resting on a yellowish sandy subsoil, 

 from one to two feet deep, when it changes to clay. Natural 



