GEOUXD OPERATIOXS. 



13 



porated with the soil : whereas a full half of maiden 

 surface soil added to that on the spot, will gene- 

 rally he found of the greatest ser\ice, and render 

 it far more valuable for all horticultural purposes. 



But the subject of deepening will recur under the 

 head of " Trenching," and the chief point here is to 

 insist on the necessity of so levelling the subsoil, 

 either by bodily removal or incorporation with that 

 on the spot, that the surface soil should cover it 

 everj^where to the same depth. Those most conversant 

 with the economical performance of ground opera- 

 tions will see that this levelling process should com- 

 bine the merits and advantages of trenching, digging, 

 and manuring as well. After levelling the subsoil 

 it should be loosened to a further depth of six inches 

 or a foot with a pick or spade, a layer of manm-e 

 spread over it before the layer of surface soil, and 

 more added during the process of filling up with the 

 mixture of the different earths. But not a few level 

 first, and it is for these chiefiy that the advice is 

 so often repeated to level soil and subsoil abreast at 

 one operation and the same time. 



Simple Modes of Levelling. — Levelling on a 

 large scale is an important bi^anch of ci^•il engineer- 

 ing, and requires a theodohte. and other expensive in- 

 struments and appliances. It is not such ascertaining 

 or alteration of levels, on a large scale, that is re- 

 ferred to here, but rather of inequalities of surface or 

 of fall over a few acres at the most. The majority of 

 gardens are either on a dead flat or an e^-en fall, and 

 so far as the kitchen garden is concerned it is desir- 

 able that they should be so. 



Most fields, on the other hand, before being taken in 

 for gardens, are more or less uneven, and as a rule it 

 is not desii'able to perpetuate these inequalities, and 

 hence the importance of having some simj)le means 

 of removing them. So many words, figui^es, and 

 diagrams have been expended on tliis subject, with 

 the result of frightening people away from it rather 

 thar teaching the art of levelling their own garden, 

 that one almost fears to approach it. 



In most gardens the starting or standard points 

 are already predetermined for the operator, the house 



L 



Pig. 2.— Straight-edge with Level. 



or mansion on the one hand, and the park, fields or 

 STirrounding country, public or private roads, and so 

 forth, on the other. The problem is thus much sim- 

 plified, for few operations can be more simple than 

 the making of ground between two points perfectly 

 level, or on an even regular fall all the way. The 

 only implements needed are a measm-ing-rod ten feet 



long, marked into feet and inches all the way, a 

 straight-edge (Fig. 2) or triangular foot level (Fig. 4), 

 a quadrant (Fig. 3), three borning-rods, a buncUe of 

 straight stakes, either with or without cross-bars, 

 movable or otherwise, at the top, some smaller stakes, 

 and a mallet. 



In levelling such an irregularly- shaped piece of 

 ground as Fig. 5, place a row of stakes at equal dis- 



Quadrant. 



Triangle-level. 



tances of ten or twelve feet along its surface, and 

 of an}' convenient height. Having placed the first 

 two in position, take the straight-edged spirit-level 

 (Fig. 2), place it on the tojD, and see that they are 

 made exactly level. Then drive a third in, and 

 level it to a dead level with the second, and so with 



Fig. 5.— Levelling with Stakes and Rods. 



the fourth, and aU through to the end. This will 

 form a level line at any handy distance from the 

 earth, the exact height being in no way material. 

 As the slightest mistake becomes of material impor- 

 tance in a long line, it is desirable to test the level- 

 by sighting it over a quadrant, or by sighting on 

 a second level, reversing the end of the level be- 

 tween every pair of stakes. Two points must be 

 specially noted at this stage. The gauge for forming 

 a level surface is already pro\'ided by the level line 

 on the top of the stakes, and it is quite clear that 

 by measuring the same distance down from the top 

 of each stake, the earth-line would be as level as 

 this line in the air. But the second point is, where 

 is the surface line of the garden to be P This can 

 be settled thus : — ^Measure the distance fi'om each 

 stake to the original surface, and set the distance 

 down, and so on with all the other stakes throughout. 

 As the ground varies in height less or more at either 

 end, it is better, for the sake of greater accuracy, to 

 measure the two ends separately, add the product, 

 di%-ide by two, and set down the half under the other 



