7 



during the growing season, at eaohi of the stati ons emplopied, 

 and growth measurements were made after about two vreeks and 

 again after about a month. The plants were hari'ested at the 

 end of the longer period. 



While several different plant species ?,-ere employed 

 throughout the experimental work, the present paper deals 

 only with the data obtained from soy-bean. A variety of this 

 olant called "Peking", v/as used. The seed was oT' pure str-.in 

 obtained from the 1913 crop of the Maryland Agricultural 

 Exoerimert Station. All the seeds were first treated with 

 carbon bisulphide vapor for one week, to destrogr insects, 

 after which they were placed in paraffined paper cylinders 

 with tight- fitting covers and stored until ready for use. 



The same kind of soil was used in all of the plant cul- 

 tures, at al 1 stations. It w'lS a rather light soil obtained 

 from an untilled field near College Pari?, Maryland, and was 

 of the type classified as ITorfolk Sand by Bonsteel. ""he top- 



Bonsteel, J. A., "^he sojls o.^' "^rince C^eorfrels '^oimty. Pub. 

 Maryland ^eo?.ogioal Survey. Baltimore, 1911. 



soil was removed from a small area of the field to a depth 

 of 15 cm. , and thoroughly mixed and sifted. It was then -nlaced 

 in cloth sacks and shipped to the various stations where it 

 was stored in air-dry condition. in covered, water-tight, gal- 

 vanized iron cylinders, until needed for use in the cultures. 

 The soil cnntainers for the cultures were ordinary "6 inch", 

 porous clay flower-pots , in form like the frusticxiin of a cone, 

 being smaller at the bottmm, and of a cubiri capacity of approx- 

 imately 1980 cc. 



