16 



THE GARDENER'S ASSISTANT. 



Measure up 4 feet from I to p, and down 

 from h to i; the line ip will correspond with 

 a slope requiring a less amount of labour than 

 any other to reduce the undulating surface, 

 represented by the dotted line, to a uniform 

 inclined plane. It will be observed that the 

 rising ground opposite a has only to be turned 

 into the hollow at b, and the projection at c 

 will suffice to make up the adjoining defi- 

 ciencies near d; and with these two simple 

 operations the work is completed. If a steeper 

 slope were to be adopted, it is evident that a 

 quantity of soil would have to be moved up- 

 hill from near i towards p. If, on the con- 

 trary, the slope were to be made less than that 

 represented in the figure, more than the mini- 

 mum quantity of soil must be moved, although 

 easier, of course, than in the other case, be- 

 cause downhill. 



Hitherto the directions have been given for 

 levelling a line, such as the edging of a walk, 

 or a strip like a border, which, although slop- 

 ing irregularly in the direction of its length, 

 was supposed to be all along horizontal across. 

 If those directions are well understood, there 

 will be less difficulty in comprehending a more 

 complicated part of the subject, which must 

 now be entered into. 



If the ground undulates with a general slope 

 in one direction, say from north to south, and 

 if it does so regularly across the whole area, 

 the instructions already given will be sufficient; 

 but it may also slope irregularis in other direc- 

 tions, so that neither the perfect level nor the 

 general uniform slope of the least expensive 

 formation can be so easily determined. 



The substratum should be so regulated as to 

 be a certain distance below the surface, namely, 

 the estimated average thickness of the top-soil. 

 The soil and subsoil may be worked accord- 

 ingly, but both too high. By reducing the 

 surface to the proper level, the depth of good 

 soil, so far as the reduction goes, will be less 

 than it ought to be, unless the substratum be 

 also lowered. In order that such unsatisfactory 

 and expensive labour may be saved, due care 

 should be taken to ascertain the proper average 

 level of the whole ground. In order to do 

 this it is necessary to find at some convenient 

 height a number of points in the same hori- 

 zontal plane, so that from these the average 

 depth of the space between that plane and the 

 surface of the ground can be ascertained. Place 

 a rod at each corner, as a, b, c, d (fig. 799), and, 

 taking care to place the instrument half-way 

 between the rods, in case of error from the line 



of sight not being exactly parallel with the axis 

 of the spirit-tube, mark level points on the rods, 

 say a and b, move the instrument to one of the 

 adjacent sides, as between b and d, and mark 

 similar points on each of theim Now, it will 

 rarely happen that the marks on the rods taken 

 from station / will correspond with those taken 

 at station g. The difference, however, whether 

 higher or lower, will be seen on the rod b. If 

 it be, say, 10 inches lower, then 

 mark 10 inches above the level 

 point on the rod d, and this mark 

 will correspond with the levels 

 first taken between a and b. Pro- 

 ceed in the same manner with the 

 levels between dc and ca, and thus 

 four points, one at each corner of the ground, 

 will be obtained in the same horizontal plane. 

 If the ground is not very irregular, place rods 

 at equal distances in line from end to end and 

 across, so as to form the whole into squares, 

 and by viewing from the level points at the 

 corners, as from a to b, mark others on the 

 rods placed intermediately along that line, and 

 likewise on the rods on the opposite side, be- 

 tween c and d; and by viewing between each 

 pair of opposite rods on these sides, the whole 

 of the rods can be marked to the same level. 

 Then, by the preceding rules, find the mean 

 perpendicular of the space between the ground 

 and the horizontal line on the side a b. Mark 

 this down; and in a similar manner the mean 

 of the next parallel line of stakes, and of all 

 the other lines running in the same direction. 

 Add the mean height of the line ab to that 

 of c d, and to half the sum add the means of 

 the heights of all the intermediate ones ; divide 

 the sum by the total number of rows of stakes, 

 less 1, and the quotient will be the distance to 

 be measured down from the level mark on each 

 rod for the mean level of the ground. 



After due consideration of the foregoing 

 directions and examples, with a little practice, 

 anyone may understand how to level suffi- 

 ! ciently well for garden purposes. The best 

 instrument for speed and accuracy in taking 

 levels is a well-made Dumpy's Level, and 

 everyone who has a garden, or any other im- 

 portant piece of ground to level and lay out, 

 ought to possess that handy and accurate in- 

 strument. Some may raise objection to its 

 cost, but it soon repays itself in saving time 

 and extra work; and if the first cost is con- 

 sidered too much for the job to bear, it can at 

 least be hired for a trifling sum, which is gener- 

 ally saved in a single day's work. 



