44-2 Hemarl'S and Observations suggested 



the same rules should be observed. The compost used should 

 be dry, and broken small with the spade. For large seeds, the 

 surface may be left more rough, to keep it open ; for small seeds, 

 it should be sifted very fine for the surface; and the smallest 

 seeds, as rhododendrons, should have hardly any covering at all. 

 The glass should be covered with a mat, to screen the light 

 when the sun is strong, as it tends to stop germination by 

 keeping the carbon fixed, evaporates the moisture, and skins the 

 surface of the soil ; but, as mats prevent the heat from entering, 

 which is much wanted, they should be thrown off whenever the 

 weather is dull and cloudy, and should be taken off soon in 

 the evening, and delayed putting on as long as possible in the 

 morning. A better screen for the light would be strong paper 

 oiled : this substance excludes and refracts the rays of light more 

 than glass; and, as the refraction of the rays by our atmosphere 

 is the cause of heat, it will be found, that in frames covered with 

 oil-paper, the heat is much greater than in those covered with 

 glass; and, if made sufficiently strong to keep out rain and 

 wind and wear well, a frame with the sashes constructed of oil- 

 paper in place of glass would be the best for germinating seeds, 

 though, from the want of light afterwards, and from that light 

 being of a rather too yellow colour, they would not grow so well 

 if continued under it. Covering the pots with saucers and pieces 

 of glass increases the heat by confining the air, and retains the 

 moisture by preventing evaporation ; a cover of oil-paper would 

 be better than either of these, and there would be less need for 

 shading if all the pots had these covers, and the heat would 

 thus be greatly increased ; the covers must be taken off as soon 

 as the young plant appears, or rather just before it appears, or 

 it will come etiolated and weak from too much stimulus. The 

 quantity of water given to seeds must be regulated by the nature 

 of the seeds. Oily seeds, as the genus Pinus, &c., require least 

 water, and are the most easily hurt by excess ; resinous and 

 waxy seeds, as the genera Picea, Magnolm, &c., do not require 

 much ; farinaceous seeds, as the genera ^^bies, iarix, y^cacia, 

 &c., require most. Much depends on the heat of the bed, the 

 shading, the open or close texture of the compost, the drainage 

 of the pots, and the natui'e of the pots themselves. Hard vitrified 

 pots are not at all suitable for tender seeds. The surface should 

 be allowed to dry now and then to prevent skinning. When the 

 heat of the bed is such as to require a good deal of water there 

 is more chance of success, by the stimulus given to vitality, and 

 the expansion and decomposition of the water. 



In the sections Seed-savini; and Packing of Seeds, there is 



.... 



much concerning the sterility, fertility, and parentage of seeds 

 that should be carefully studied. Moisture is there said to be 

 prejudicial at the time the plant is in flower ; heavy rains wash off 



