FRUITS AND SEEDS 247 



a layer of potsherds or cinders. Then the seeds are spread 

 out singly over the sand and covered with another layer of 

 sand. The number of layers of seeds which may be placed 

 one above the other, and the thickness of the intervening layer 

 of sand, depends upon the porosity, and therefore upon tlie 

 coarseness of the sand. The more porous the latter is and the 

 larger the seeds, the greater the number of layers which may 

 be arranged one above the other. The layer of sand should 

 never exceed three inches, and more than six layers of seeds 

 should not be piled up, as one of the chief requisites, namely, 

 thorough ventilation of the soil, can then not be effectively 

 secured. The moisture must not be too great, but constant. 

 The time at which to begin this stratification depends upon 

 the time the seed requires for germinating. The more rapidly 

 the latter takes place, the later must this process be under- 

 taken, as the radicles must not have grown out much when the 

 seeds are transferred to the open. The effect of this process is 

 heightened by immersing the seeds in water before they are 

 laid in layers, or by keeping the temperature up. The cellar 

 is usually the best place for this process. If a very large 

 quantity of hard seeds whicli require to be moistened for a 

 considerable time (Ash and Sycamore) are to be dealt with, 

 they may be placed in the open in pits or mounds in a similar 

 manner. 



It is, however, still an open question whether fresh seeds 

 are always the best for sowing. In most cases this will be 

 the case ; indeed, in some which soon lose their vitality 

 (Willows, Poplars, Elms) it will be absolutely necessary ; but 

 we find exceptions to this rule. Many practical gardeners, 

 indeed, affirm that old seeds of melons and cucumbers do not 

 run to leaf so much as fresh ones. This might be readily 

 explained ; for we know that plants which have always been 

 copiously supplied with water transpire more from their leaf 

 surface and have a more vigorous development of leaf surface. 

 It is also known that an artificial drying of seed-potatoes or 

 onions causes the production of short-shooted plants, which 

 more readily form tubers and bulbs, and this might also be 

 the case with the seeds of the melon. If seeds are kept for 

 a long time in a dry atmosphere and with little oxygen, they 



