two successive crops of potatoes, yielding together 742 bushels; at the same time, the same quantity of yard dung, after 6 months rotting, yielded 708 bushels, leaving [to the fresh long dung] a superiority of 34 bushels. But had the fresh dung been kept as long as the other, it would have required at least twice, perhaps thrice as much, to have produced the quantity used." [That is, twice or three times 67 loads of fresh long dung, if kept and often turned and mixed to produce fermentation and rotting, would have shrunk, or been reduced, to 67 loads of short rotten dung.] "If the crops therefore had been only equal, still the advantage [of the fresh dung] would have been most decisive." [14] The Trench-Plough of Mr. Ducket's invention was so admirably contrived as completely to bury whatever was intended to be turned in. Mr. Young says he saw him turn down a crop of rye, six feet high, so that not an atom was left visible; and yet the depth did not exceed eight inches. Trench ploughing has sometimes been effected in this country by a second plough following in the same furrow after the first, and going a few inches deeper. "I shall not quit (says Mr. Young) the husbandry of two men who carried tillage, on soils so extremely different, to its utmost perfection, without remarking the circumstances in which they agreed. Both were equal friends to deep ploughing; both rejected the common repetition of tillage, and reduced the number of their operations to a degree that merits attention; both rejected fallows; and both ploughed deeply for depositing manure, without any apprehension of losing it. These are very important points in Practical Agriculture."