SELf:CTION AND SAMPLING OF 'SEED. 165 



I 



moisture percentage is undergoing constant variations 

 with the hygrometric conditions of the ambient atmos- 

 phere.* The moisture of a sample of seed is deter- 

 mined by weighing a given quantity before and after 

 drying at a temperature of 105 degrees C. (221 degrees 

 F.) during a period of 465 hours. If five grams are 

 heated in a platinum capsule, the loss of weight multi- 

 plied by twenty gives the weight of water contained in 

 a hundred grams of seed. This amount it is impor- 

 tant to know, as if in excess of 15 or 18 per cent, it 

 indicates a bad conservation, which is a very objection- 

 able feature. 



An interesting fact which has recently been brought 

 to light is, that there seems to be some practical relation 

 between the moisture of the seed and its power of ger- 

 mination. These experiments were mainly undertaken 

 by Dr. Bretfeld. It is concluded by him that the ger- 

 minating power increases with a decrease in percent- 

 age of moisture. However, the following data show 

 that the variations are very slight and no great impor- 

 tance need be attached to them. The experiments 

 extended over a period of four years; with 13 per cent 

 moisture there were 159 per cent, of germs (each seed 

 containing several); with 12.5 per cent., 194 per cent, 

 of germs; 13.6 per cent., 133 per cent, of germs; 13 per 

 cent., 153 per cent, of germs. The great variations in 

 moisture of seed depend upon their origin; the age, 

 etc., is made evident by the following series: 



Per Cent. Moisture. ~ " 



A,verage 13i 



From which we conclude, with some degree of cer- 



* See on r rem a Ties on moiQtnre under heading "General Considera- 

 tions Respecting Germination." 



