NEW ENGLAND FARMER. 



113 



BASE LINE 





Fiq-1^ 



Rugglcs, Nourse, Mason Sf Co,''s PlougJifor Lapped Furroivs — Furrows 7 by 10. 



ing it, and the two exposed faces of the slice are 

 of equal breadth, — namely, seven inches. 



Fi?. 14 represents the action of a plough una- 

 dapted to laying proper lapped furrows. The plough 

 is so wide upon the bottom as to require a width of 

 furrow-slice of at least twelve inches, and yet it 

 cannot go more than seven inches deep; indeed it can 

 hardly do that, without crowding over to the left or 

 land badly, and it cramps and breaks the slice very 

 much. But the slices are of unequal proportions. 

 The width is too much for the depth, and conse- 

 quently, so flat a surface is formed, that if the fur- 

 rows are to lie exposed for some lime to the weather, 

 and if the soil be a stiff adhesive clay, it will run 

 together and bake so much as to render the harrow 

 quite inoperative, and but a shallow seed-bed will 

 be raised. The spaces underneath the furrows are 

 wide and low, and they will be apt to fill with soil, 

 which will prevent a proper circulation of air, and 

 a free passage of superfluous moisture, and the sur- 

 face will be apt to be wet and heavy. 



The triangles, abc, efg, Fig. 13, are of equal 



sides, and the angles, b, f, are angles of 45°. The 

 triangles hik, klm,Fig. 14, are of unequal sides, and 

 the angles, i, k, are angles of only 30'^. If we sup- 

 pose a series o{ sections of these 7 by 10 and 7 by 12 

 furrow-slices, each extended to ten rods, for in- 

 stance, in width, and that they are one inch thick, 

 we shall find upon a calculation of the aggregate 

 exposed surface of each, that the furrow sections, 

 7 by 10, of equal faces, have exposed 2791 inches 

 of surface to the air, while the sections, 7 by 12, of 

 unequal faces, have exposed 2722 inches; and any 

 one who chooses to extend the calculation and 

 comparison to the acre of ground, will find the 

 balance to be very much in favor of the slices rep- 

 resented in Fig. 13. A like comparison of rectan- 

 gular furrow-slices, whose depth is to their width 

 as two is to three, and which are laid at an inclina- 

 tion of 4-5'^, with furrow-slices of any other form, 

 or proportions, that are practicable to be laid, will 

 be found to result in favor of those first named; — 

 indeed it can be shown that no furrow-slices but 

 rectangular ones, whose depth is equal to two-thirds 



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