269 



?. OTHER OILS 



111 addition to the kerosene the effects of a number of other 

 petroleum oils have been studied. At the present time only the in- 

 itial results have been obtained. These results indicate that the in- 

 juries due to the penetration of the dormant grains by the oils are 

 'essentially the same as in the case of kerosene. The effects on the 

 germinating grains, however, differ very widely. The more volatile 

 oil (gasoline, Table i6) produces no more injury than does the kero- 

 sene. From present indications it seems probable that a high moisture 

 content of the soil affects the grains immersed in the more volatile oils 

 less than those immersed in kerosene. On the other hand, the injuri- 

 ous effects of the heavier oils on germinating grains in soils of either 

 low or high moisture content are much more pronounced. The same 

 means were employed for eliminating these oils from the grains after 

 immersion as were used with the kerosene; viz., wiping the grains 

 carefully with a towel and then exposing them to the air. The heavier 

 oils do not volatilize as completely as the kerosene and gasoline do. 

 The residues dry on the grains, producing a hard coating which pre- 

 vents normal germination. 



At present the trend of evidence tends to show that the grains 

 bear immersion in the lighter oils without injury for much longer peri- 

 ods than in the heavier oils, and that the injurious after-effects of the 

 latter are more pronounced than those of the former. 



Series D 



Tables ij to 20 inclusive. Comparisons between kerosene and 

 other petroleum oils. Champion White Pearl Corn germinated in a 

 23% saturated soil. 



Table 15. Kerosene (Control) 



Table 16. Gasoline 



