682 UTILIZATION OF THE FRUITS OF FOREST TREES. 



they then always retain a few seeds and in order to secure 

 these, they are placed in a drum-sieve (Fig. 366, />), which is 

 made to rotate. 



This consists of a cylinder with wire sides, open at both ends, 

 and there are often projecting bars fastened here and there to 

 its axle inside the cylinder which assist in shaking the cones. 

 It is turned slowly by means of a pulley and belt. The cones 

 are poured into the drum- sieve through a hopper and are so 

 thoroughly shaken within it, as to part with all their seeds. 

 The seeds fall on to the floor and the empty cones pass out at 

 one end of the drum-sieve, which is slightly inclined in that 

 direction, through a second funnel, into the store-room for 

 empty cones. 



Removal of the wings of Scots pine and spruce seed may 

 be effected in various ways. On a small scale, and if it is con- 

 sidered sufficient to remove the greater part of the wing, 

 leaving a small fragment attached to the seed, the dry pro- 

 cess is employed. In this case linen sacks are half filled 

 with seed (the mouth of each sack being tied) and beaten with 

 light flails, being turned and shaken and rubbed until the 

 wings are removed. In wholesale establishments a different 

 method is usually employed, termed the wet process, which 

 gives quicker results. The seed is then piled 6 to 8 inches 

 high on a paved or planked floor, sprinkled lightly with water 

 from the rose of a watering-pot and then beaten energetically 

 with leather flails. In many seed-depots hardly any water 

 is used and yet the wings are removed completely. Newer 

 methods are ; to pass the seeds between two rotating stones, or 

 to place them in a drum with revolving brushes (detacheur). 



In order to obtain clean silver-fir seed, more trouble 

 must be taken. The moistened seed then generally must 

 be heated, so that very clean silver-fir seed is regarded with 

 suspicion. 



Frequently objection is made to the wet process, that it 

 prejudices the germinative power of the seed. This objection 

 is justified, if the damp seed is kept in heaps and allowed to 

 ferment, so that the wings may separate from the seed without 

 any further mechanical treatment. If, however, the method 

 already described is followed and no fermentation allowed, the 



