1916] SHULL—SOILS 29 
_ My thanks are due to Professor L. E. CALL, of the Kansas State 
Agricultural College, Manhattan, for sending me the subsoil of the 
Oswego silt loam used in these experiments, and to Dr. Lyman J. 
Briccs and his assistants in the biophysical laboratory of the 
Bureau of Plant Industry for making determinations of the moisture 
equivalent of the local soils, hygroscopic determinations of the seeds 
in the vacuum driers, and for the various soil types which were so 
kindly sent to me. I desire also to express my appreciation of the 
generous way in which the Hull Botanical Laboratory has provided 
all needed facilities for the work, and especially my indebtedness 
and gratitude to Dr. WILLIAM CrRrocKER for much helpful advice 
and encouragement received during the progress of the work. 
UNIVERSITY OF KANSAS 
LAWRENCE, KAN. 
LITERATURE CITED 
1. ALway, F. J., Studies on the relation of the nonavailable water of the soil 
to the hygroscopic coefficient. Neb. Agric. Exp. Sta. Research Bull. no. 3. 
5-122. 1913. 
2. BANCROFT, WILDER D., The action of water vapor on gelatine. Jour. Phys. 
Chem. 16:395-406. 1912 
3. Bocpanorr, S., Uber das Verhalten der keimenden Samen zum Wasser im 
allgemeinen, und speziell zur Bodenfeuchtigkeit. Landw. Versuchs-Stat. 
42:311-366. 1893. 
4. Brown, A. J., On the existence of a semipermeable membrane enclosing 
the seeds of some of the Gramineae. Ann. Botany 21:79-87. 1907. 
5. Brown, P. E., and Surru, R. E., Bacterial activities of frozen soils. Iowa 
Agric. Exp. Sta. Research Bull. no. 4. 1912. 
6. Briccs, L. J., and ac haae 2 W., The moisture equivalents of soils. 
7. Bricecs, L. J., and SHANTz, ay 1. The a coefficient and its indirect 
determination. Bor. Gaz. 5320-37. 19 
, The wilting coefficient for different plants and its indirect deter- 
mination. Bur. Plant Industry Bull. no. 230. 1912. 
9- CALDWELL, J. S., The relation of environmental conditions to the phe- 
nomenon of permanent wilting in plants. Physiol. Res. 1:1-56. 1913. 
10. CAMERON, FRANK K., The soil solution. torr. 
tz. CARTER, WILLIAM T., Jr., and SmirH, Howarp C., Soil survey of Riley 
County, Kansas. sth senoits Field Operations of the Bureau of Soils, 
PP. Q9II-941. 1906. 
8. 
