Jan. 3, 1921 



Amount of Unfree Water Caused by Seeds 



589 



seeds in the dilatometer were thawed and refrozen either at the temperature 

 of — 3 or of — 20 C. In the latter case, the contents of the dilatometer 

 were allowed first to supercool at — 3 and to assume equilibrium at this 

 temperature; then they were put in the temperature of — 20 , allowed to 

 remain there for about one hour, and were then placed back into the 

 temperature of — 3 and allowed to attain equilibrium. 



In all, 14 different kinds of seeds were used. These were spring 

 wheat, winter wheat, barley, rye, white corn, yellow corn, broom corn, 

 alfalfa, alsike clover, mammoth clover, cowpeas, field peas, field white 

 beans, and black soybeans. 



In Table I are presented part of the data obtained. They show the 

 amount of water the different kinds of seeds absorbed and the quantity 

 they caused to become unfree, as indicated by its refusal to freeze for the 

 first time at the temperature of — 3 C. The quantity of unfree water is 

 expressed both in cubic centimeters and in percentage based on the 

 weight of the air-dry seeds. The factor used for converting the volume 

 of expansion due to the ice formation into the corresponding weight of 

 water was that obtained experimentally and used in the study of the 

 soil — namely, 1 cc. of water expands approximately 0.1 cc. upon freezing. 



Table I. — Amount of water that failed to freeze in seeds when they were supercooled and 

 frozen for the first time in a temperature of — j° C. 



Kind of seeds. 



Spring wheat. .. . 

 Winter wheat . . . 



Barley 



Rye 



White corn 



Yellow corn 



Brown corn 



Alfalfa 



Alsike clover. . . . 

 Mammoth clover 



Cowpeas 



Field peas 



Field white peas 

 Black soybeans. . 



Weight of 

 air-dry 

 seeds. 



Gm. 



11. 2IO 

 xi. 250 



10. 770 



10. 230 



12.07s 



12. 215 



10. 020 



11. 3OO 

 II. 200 

 II. 200 



9. 2IO 



10. 070 



10. 275 



7. no 



Weight of 

 water- 

 soaked 

 seeds. 



Gm. 

 18. 290 

 18. 510 

 18. 080 

 18. 150 

 17. 640 

 17. 265 

 16. 230 



25- 73° 

 24. 200 

 25.700 

 20. 790 

 20. 800 

 20. 320 

 16. 920 



Absorbed water which 

 failed to freeze. 



Cc. 



2.880 



3-36o 



4-3 xo 



3.920 



3-765 

 4.650 

 2. 510 



8.430 

 7. 400 

 7. 100 

 6.680 

 7-73° 

 5-445 

 5-3io 



Per cent. 

 25.70 

 30. IO 

 40. 02 

 40. 20 

 3I-I8 

 38.09 

 25-05 

 74. 60 

 66.08 

 63.40 



72-54 

 76. 76 

 52.96 

 74.68 



From the foregoing experimental data it is at once seen that the 

 amount of water which the seeds cause to become unfree is really very 

 great in nearly all the different kinds of seeds. It varies from about 

 25.05 per cent with broom corn to 76.76 per cent with black soybeans. 

 It appears that the alfalfa, clover, cowpeas, and bean seeds cause a 

 considerably larger amount of water to become unfree than the wheat, 

 rye, barley, and corn seeds. As has already been mentioned, this 

 17777°— 21 6 



