BOOK III. 



IMPLEMENTS OF GARDENING. 



279 



preparation of the soil, the curvilinear parts of such parterres can be described by them 

 with perfect accuracy. The stationary foot is placed on a slip of board a few inches 

 square, with a pin beneath to retain it in its place, and a lead cap above for the point of 

 the foot. 



1367. The borning-piece (Jig. 156.) is composed of the body (a), commonly a thin slip 

 of board, four inches wide, half an inch thick, and four feet two inches long ; the head 

 (6) of a similar slip of board placed across, but only eighteen inches long ; and the foot 

 is either of the same form as the head, or merely the squared end of the body (as in the 

 figure). The upper and under edge of the head and foot must be perfectly straight, and 

 form right angles with thp edges of the body. Borning-pieces are used to prove, com- 

 plete, and continue level lines, or lines on certain given slopes. One is placed at each 

 end of a convenient length of the level or slope, and there held perpendicular to its sur- 

 face, and others, being placed in the interval, and in the same line or vertical plane, 

 the ground under the feet of the intermediate borning-pieces is raised or lowered till it 

 is brought to the proper level or slope, when the upper edges of all the heads will range. 

 Where box-edgings are to be planted with accuracy and beauty, the use of these imple- 

 ments cannot be dispensed with. 



1368. Of levels (figs. 157 & 158.) there are a variety of sorts ; but the most con- 

 venient is half a square, with an iron index in the angle marked with ninety divisions or 

 degrees. The use of these degrees is to facilitate the laying out of slopes ; at a perfect 

 level the plummet will hang at 45, and for a slope it may be any lesser number in ascend- 

 ing, or any greater number in descending from a fixed point. This level may also be 

 used as a square to set off right angles, or indeed angles of any description. 



1369. The adjusting horizontal level (,fig. 157.) is peculiarly useful in laying out roads, 

 or regulating the slope of lawns or borders, as is also the following instrument. 



1370. Dalsde'l's level, (fig. 159.) This is an instrument of a very simple description, 



159 



I 



lately invented, for ascertaining the relative elevation of unequal surfaces. It consists of a 

 wooden bar (a) with a foot at one end (6), and at the other another larger foot with a groove 

 and scale (c), to which the bar is connected by a screw and nut. ' In using this instru- 

 ment, two points of different altitude being chosen, the support of the bar (6) is to be 

 placed on the higher, and (c) the foot of the scale on the lower, while the position of both is 

 secured by a slight turn of the thumb-screw. The bar being brought parallel to the horizon 

 with the plummet (rf), will indicate, that the upper part of the scale is to be advanced, or 

 the reverse, keeping its foot on the point of support, until some one of the graduations 

 coincides with, or is visibly parallel to the upper edge of the bar. The difference of alti- 

 tude sought is seen in figures, without calculation. Any person that understands the use 

 of a level will see a variety of levelling operations on a small scale that this implement is 

 calculated to simplify : for example, if it be required to construct an inclined plane, rising 

 an inch in a foot, the inner edge of the scale is to be brought six feet from the foot end 

 of the horizontal piece, and rendered perpendicular to it, by making the graduated line at 

 six inches coincide with the horizontal edge of the bar. Being fixed immoveably by the 

 screw in that position, the surface of the ground is then to be worked until the plummet 

 hangs perpendicularly. The first six feet of the inclined plane having been thus con- 

 structed, other portions are to be taken successively throughout the remainder. If a plane 

 of a different inclination is required, as of half an inch in a foot, the scale is to be shifted 

 to three inches, and so on. (High. Soc. Trans, vol. v. p. 575.) 



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