LARCH SEED. 765 



damping being merely auxiliary to the threshing, clean seed with 

 good germinative power is obtained. 



An excellent method for nearly all winged seeds is to put 

 them between the stones of a flour-mill, placed the right distance 

 apart. As then the process is merely a dry one, there is no 

 danger of the germinative power of the seed ; it is, however, 

 difficult in this way to produce thoroughly clean seed. 



Once the wings have been severed from the seed, they must 

 be removed in order to obtain clean seed. This is effected either 

 by swinging the seed on a wooden tray, or tossing it with a 

 wooden winnowing-shovel, which removes both the wings and 

 light worthless seeds. As a rule, however, the seeds are placed 

 in a modern corn-sifter, provided with several graduated fine 

 wire-sieves. This completely separates all impurities and the 

 worthless seeds from the good seed, the workman being careful 

 to turn the machine slowly. 



Section It. — Separation of Seed from Larch Cones. 



The method described in Section I. refers only to Scotch pine 

 and spruce ; it is not applicable to larch cones, which cannot be 

 completely freed of seed by artificial heat without damaging its 

 germinative power. Only the upper part of larch cones opens 

 when subjected to heat, the base of the cones, which contains 

 most of the seeds, remaining closed. Larch cones must there- 

 fore be torn open in machines, clean seed being obtained only 

 after much troublesome manipulation. 



Formerly, larch cones were placed in stamping-mills, where 

 they were completely crushed, or apparatus used somewhat 

 resembling turnip-cutting machines. In these, two rollers of 

 diflereut diameters, provided with fairly contiguous., sharp knives, 

 an inch long, are turned in the same direction on their axles, 

 leaving only space enough between them and their correspond- 

 ing knives for the wooden axes of the cones to pass. The scales 

 and seeds of the cones, which enter the machine from above the 

 rollers, are thus separated from their axes. This process, how- 

 ever, destroys much seed. 



More recently use has been made of hand-machines of similar 

 structure to the above, but in which the knives are replaced by 



