PROPAGATION. 53 



and then cover with an eighth of an inch of finety sifted 

 mould. Lightly press the surface again, and cover the box 

 or pan with a pane of glass. The pans or boxes may be 

 placed in a sunny, cold .frame, or in a cool greenhouse. 

 Shade from sun with a sheet of paper. Watch the sur- 

 face of the mould daily, and directly it shows signs of 

 getting in the least degree dry, give it a gentle watering. 

 The soil must not be allowed to get too dry or too wet, and 

 this is why it is better not to give water at the time of 

 sowing. Too much moisture, moreover, will cause the 

 seeds to rot. In ten days to a fortnight the seedlings will 

 begin to appear, and then the glass must be tilted a little 

 to admit air. As soon as the seedlings show themselves 

 freely, remove the glass. When the third leaf forms, care- 

 fully transplant each one into a thumb pot. The compost 

 for this purpose should consist of equal parts of good soil 

 and leaf-mould, with a fair amount of sand. Do riot press 

 the soil too closely in the pot. Stand the seedlings not far 

 from the glass, and attend carefully to watering and air- 

 ing during the day. As soon as the seedlings are nicely 

 rooted, shift them into three-inch pots, and keep in the 

 frame till all danger of frost is past ; then plant out in P 

 good and properly prepared plot of ground to produce their 

 first crop of tubers. When the crop has reached maturity, 

 lift the roots, and keep each one separate. Examine them 

 carefully, selecting only those of great promise to grow 

 again, and discarding the remainder. Probably two-thirds 

 of the roots will be useless. Store the selected tubers, 

 and plant these out in the ordinary way the following 

 spring. In due course, lift and examine the produce, 

 selecting the best as before and rejecting the remainder. 

 Proceed thus year after year, for four or five years, until 

 you may perhaps get one, or, at the most, two, varieties 

 that promise to be distinct improvements on existing 

 kinds. The best time to sow is in March or April. It is a 

 good plan also to bake the soil used for covering the seeds, 

 in order to prevent the " damping off " fungus from de- 

 veloping and destroying the young seedlings. 



