594 



Journal of Agriculture, Victoria. [15 Oct., 1919. 



after the first furrow has been made. Plate No. 24 shows two of these 

 ploughs at work at Panton Hill stirring the subsoil to the depth 

 mentioned. 



By doing the preparatory work in this way, the subsequent spade 

 work is facilitated. For lateral drains, the width of ditch at the surface 

 should be about 15 inches, as no more soil than is necessary should be 

 removed, and it should taper off to about 6 inches at the bottom. For 

 larger drains, it may be necessary to increase the width a few inches 

 as required. It will be found more satisfactory to commence the work 

 of ditching at the outlet, as it will then be easier to determine the 

 proper grade. 



As much of the excavation as possible should be done with the spade, 

 and for finishing off the work neatly, as the ditch narrows down, a 

 properly tapered drainage spade and scoop will assist greatly in the 

 perfection of the task, care being taken to make the hollowed-out bed 

 for the tiles as accurate as possible. 



■s---:^^': 



^«*^?^M§^ 



Plate 24.— Sub-soiling -with Syracuse ploughs at Panton Hill. 



When the surface of land is comparatively level it will, in order to 

 obtain an even grade, be necessary to use some means of accurately 

 gauging same, for it is a difficult matter to determine it by sighting 

 alone. 



A simple instrument for the purpose, and one easily made, is illus- 

 trated in plate No. 25. As will be seen, this grading-board is set to 

 give a fall of ^- inch in 10 feet, or 3j inches in 100 feet, which is about 

 the grade required to give satisfactory results. 



The grading-board should be used as follows: — Place two tiles 10 feet 

 apart over all in the bottom of the excavation, and the grading-board 

 upon them. If the plumb-line shows a dead centre, the grade is correct. 



Should it be required to use the grading-board as a level, it may be 

 so used by tacking a piece of wood §-in. thick on the tapered end of 

 board adjusting the line, and then using it in the ordinary way. After 



