16 NATURE TEACHING 



stones separated from the soil by means of the coarsest 

 sieve. Over the stones place a layer of about the same 

 depth, of coco-nut fibre or of the dry chopped grass, to 

 prevent the finer material choking up the spaces between 

 the stones. Over the fibre or grass put a layer of the 

 gravel, and fill up the box with sifted earth. Level this 

 last layer by means of the tool, at the same time com- 

 pressing the earth slightly. If the soil is very dry it is 

 advisable to water it now, as less damage is likely to be 

 done than by heavy watering after the seeds have been 

 sown. 



The seeds may now be sown, the method of proced- 

 ure depending on the size and kind of seed. If small 

 seeds, like lettuce, are being sown, all that is necessary 

 is to scatter them evenly and thinly over the surface, and 

 then to distribute a layer of the very fine soil over the 

 seeds, sifting the soil lightly on and adding only so 

 much as is required to cover the seeds without burying 

 them at all deeply. If larger seeds, such as peas or 

 beans, are being sown, place them in shallow furrows, 

 lightly marked out with a piece of stick or with the 

 finger, and cover with very fine earth as in the previous 

 case. Very large seeds, such as horse chestnuts or 

 acorns, may be placed in position, buried by pressure 

 about half their own depth in the soil, and then covered 

 with moderately fine earth. 



Everything being completed, press the soil gently 

 down with the tool. This pressing down has the effect 

 of producing a firm seed bed which is necessary, in certain 

 instances, to enable the young plants to free themselves 

 from their seed-coats. It also serves to keep the top 



