General Instructions. 



along side of the pavement, though in ground moved only 

 a foot deep. The solid ground, though it has lain unmoved 

 for thousands of years, is not equal in hardness to a pave- 

 ment : it is still porous in a certain degree: even chalk 

 admits the rains and dews ; and, where the bottom is stone, 

 it has openings in it. But, the unmoved bottom, be it of 

 -what nature it may, is not so good as the moved bottom 

 which has had the air let into it. Then comes experience, 

 which universally proclaims the great benefit of deeply 

 moving the ground. Even the market-gardeners, near 

 London, when they are preparing for an extrordinarily 

 valuable crop, give their ground what they call a bastard- 

 trenching. This is done by taking off one spit from trench 

 a, for instance, and wheeling it away to the point where the 

 work is to end; then digging the bottom of trench a, as 

 mentioned at the close of paragraph 18; then turning in 

 upon that the top spit of trench b ; then digging the bottom 

 of trench b ; then turning in upon that the toj) spit of trench 

 c ; and thus throughout the piece^ This moves the ground 

 about 18 inches deep, and keeps the top soil still at the top. 

 It costs about twice as much as plain digging ; and, we may 

 be sure that it would not be done, if experience had not 

 convinced these skilful men, that there was gain attending 

 this additional expense. If, then, they do this for their cab- 

 bages and brocoli, ought a tree planter to hesitate upon 

 the subject ? 



30. The expense of trenching must necessarily differ with 

 the difference in the nature of the soil ; but, on an average 

 of soils, a man will trench three rod in a day ; and, 

 at the present price of provisions (bread 2d. a pound 

 and bacon 9d,) a man ought to earn 2s. Gd. a dav. 

 This is, then, 10 J. a rod, or 71* 13,9. 4d. an acre ; or, 

 reckoning to the utmost, suppose it to be 8/, Many a one 



