BOOK IV. GARDEN-LABORS ON THE SOIL. 365 



much as possible where aeration is the object ; to mix in manures regularly where they 

 are added ; to bury weeds not injurious ; and to remove others, and all extraneous 

 matters, as stones, &c. in every case. For all these purposes a deep open trench is 

 requisite, and that this may not be diminished in the course of the operation, it must 

 never be increased in length. If allowed to become crooked by irregular advances in 

 the digging, it is thus increased in length, and necessarily diminished in capacity, unless, 

 indeed, the dug ground is allowed to assume an uneven surface, which is an equally 

 great fault. 



1865. Weather for the operation. Digging, for pulverisation and mixing in manures, 

 is best performed in dry weather ; but for the purposes of variation, a degree of moisture 

 and tenacity in the soil is more favorable for laying it up in lumps or entire pieces. The 

 usual length of the blade of a spade is from ten inches to a foot, but as it is always in- 

 serted somewhat obliquely, the depth of pulverisation in gardens attained by simple 

 digging seldom exceeds nine inches, and in breaking up firm grounds it is seldom so 

 much. 



1866. Shovelling is merely the lifting part of digging, and the shovel being broader 

 than the spade, is used to lift up fragments separated by that implement or the pick. 



1867. Excavating is the operation of working out pits, furrows, or other hollows in 

 grounds, either for the commencement of other operations, as digging or trenching, or 

 for planting, burying manures, inserting roots ; or on a large scale, for forming pieces of 

 artificial water, &c. 



1868. levelling, in the ordinary sense of the term, as used in gardening, consists in 

 spreading abroad the soil in such a way that its surface may be nearly in one uniform 

 plane, either level or nearly so ; to be correct, this plane ought to be parallel with that 

 of tlie horizon ; but very generally an even surface, if not very far from level, answers 

 all its purposes. The terms level and even, in ground-work, however, ought to be 

 considered as quite distinct : the former should be like the surface of still water, and the 

 latter merely free from inequalities. 



1869. Marking, ivith tlte line is an operation preparatory to some others, and consists 

 in stretching and fixing the line or cord along the surface by means or its attached pins 

 or stakes, in the direction or position desired, and cutting a slight continuous notch, 

 mark, or slit in the ground, along its edge with the spade. 



1870. Trenching is a mode of pulverising and mixing the soil, or of pulverising and 

 changing its surface, to any greater depth than can be done by the spade alone. For 

 trenching, with a view to pulverising and changing the surface, a trench is formed like 

 the furrow in digging, but two or more times wider and deeper ; the plot or piece to be 

 trenched is next marked off' with the line into parallel strips of this width ; and beginning 

 at one of these, the operator digs or picks the surface stratum, and throws it in the 

 bottom of the trench. Having completed with the shovel the removal of the surface 

 stratum, a second, and a third, or fourth, according to the depth of the soil and other 

 circumstances, is removed in the same way ; and thus, when the operation is completed, 

 the position of the different strata is exactly the reverse of what they were before. 



346 



In trenching, with a view to mixture and pulverisation (Jig. 346.), all that is necessary 

 is to open, at one corner of the plot, a trench or excavation of the desired depth, three 

 or four feet broad, and six or eight feet long. Then proceed to fill this excavation 

 from one end by working out a similar one. In this way proceed across the piece to 

 be trenched, and then return, and so on in parallel courses to the end of the plot, 

 observing that the face or position of the moved soil in the trench must always be that of 

 a slope, in order that whatever is thrown there may be mixed, and not deposited in 

 regular layers, as in the other case. To effect this most completely, the operator should 

 always stand in the bottom of the trench, and first picking down and mixing the 

 materials, from the solid side (n), should next take them up with the shovel, and throw 

 them on the slope or face of the moved soil (6), keeping a distinct space of two or three 

 feet between them. For want of attention to this, in trenching new soils for gardens 

 and plantations, it may be truly said that half the benefit derivable from the operation 

 is lost. In general, in trenching, those points which were mentioned under digging, 

 such as turning, breaking, dunging, &c. require to be attended to, and sometimes an 



