New Yoke: Agricultural Experiment Station. 463 



each other and from the sides of the house by walks. With this 

 arrangement there were no pipes beneath or above any of the 

 benches and the circulation of air and the exposure of all portions 

 of the benches, to the light were more nearly uniform than they 

 were with the former arrangement. Plate XLIII shows the in- 

 terior arrangement for Crops II and III, and Plate XLIV shows 

 the north bench as arranged for Crop IV. 



The benches were divided into plats large enough to hold from 

 20 to 32 plants each, the plants being set 8 inches by 8 inches or 

 eight inches by 9 inches apart. In each test three plats were com- 

 monly assigned to each soil mixture. These were separated as 

 widely as possible so that the different soils might be alike subject 

 to any inequalities arising from varying conditions of light, heat 

 and moisture in the different portions, of the house. 



GENERAL TREATMENT. 



All plats under experiment were treated alike in all respects. 

 The day temperature during the winter was commonly kept at 

 from 55° to 60° F. and the night temperature from 45° to 50° F. 



None but head lettuce was used. Salamander was selected for 

 Crop I, the seed being purchased from a seed firm; for all sub- 

 sequent tests Rawson's New Hothouse was used, the seeds being 

 purchased from the introducer of that variety. An account will 

 be given hereafter of the various precautions which were taken to 

 securing seedlings uniform in size and vigor. For some crops the 

 seedlings were transplanted, but for others the seed was planted 

 where the plant was to stand till it reached marketable condition. 

 In every instance the seed was planted in the same soil and 

 usually in the same plat in which the plant was to be matured. 

 Eepeated measurements of the plants were taken at different 

 periods of growth so that the rate of growth on the different soils 

 might be compared. When the plants reached prime marketable 

 condition each one was weighed and with the later crop each plant 

 was also rated according to its form, solidity, texture and general 



