IOWA ACADEMY OF SCIENCES. 
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proper. The oil in the seed was more carefully studied. 
Five determinations gave the following: 
1. 100 grams of seed gave 9.8 grams of oil. 
2. 100 grams of seed gave 8.5 grams of oil. 
3. 100 grams of seed gave 9.0 grams of oil. 
4. 100 grams of seed gave 9.1 grams of oil. 
5. 100 grams of seed gave 9.1 grams of oil. 
The average of these determinations is 9.1 per cent of oil. 
PROPERTIES OF THE OIL. 
The oil is a light colored liquid at the ordinary tempera- 
ture. At 18 degrees below zero, it changes to a semi-solid. 
Its specific gravity at 8° C is 0.931 
Its specific gravity at 15° C is 0.9532 
Its specific gravity at 18° C is 0.9227 
Its specific gravity at 20° C is 0.92 
It is readily soluble in ether, chloroform, benzole, car- 
bon-disulphide, and readily so in acetone. It is not a dry- 
ing oil, as is shown by the following comparison with 
wheat and linseed oils: 
Increase in weight, parts per hundred after— 
5 days 10 15 20 25 30 
Linseed Oil..... 037 .130 .28 1.74 4.82 7 55 
Wheat Oil 037 .077 .15 .24 .30 .37 
Rhus Oil 005 .027 .054 .071 .104 .QRW 
The index of refraction was taken with a Pulfrich 
refractometer at different temperatures with the follow- 
ing readings: 
Index of refraction at 0° C 1.48821 
Index of refraction at 15° C 1.48228 
Index of refraction at 27° C 1.47779 
The absorption spectrum of the oil was peculiar. With 
a film of oil 4 m.m. thick, the whole violet end of the 
spectrum was cut off and a sharp black band appeared 
directly over the lithium band. With thicker films, the 
light was completely cut off. 
