48 EXPERIMENT STATION RECORD. 



Radishes were grown between the rows of lettuce, as is commonly 

 practiced in commercial houses. The artificial light notal)ly increased 

 the development of the tops of the radishes and slightly increased the 

 size of the roots. The heliotropic eflfect of the incandescent light was 

 greater with radishes than with any of the other plants grown. The 

 stimulating influence of the incandescent light, on the other hand, was 

 greatest with spinach. It caused the production of seed shoots in the 

 row to a distance of nearly 8 ft. from the light. Spinach plants sub- 

 ject to the influence of the light grew faster and completed their 

 growth in less time than plants grown normally. 



The records of the yield and date of first bloom of tomatoes grown 

 from seed and also from cuttings show no increase in weight of the 

 fruit grown in the light, though the blossoming period was from 8 to 

 18 days earlier and the individual fruits were generally larger than 

 when grown imder normal conditions. 



With sugar beets the tops, sugar content of the roots, and percent- 

 age of purity were considerably increased by the use of the incandes- 

 cent gaslight. The largest and heaviest roots, however, were grown 

 under normal conditions. 



The range of stimulating influence of the incandescent light was 

 studied. 



"The range of light is somewhat varia])le for different crops. In general the max- 

 imum growth was attained at 12 to 16 ft. from the light, while a perceptible increase 

 was noted at 24 ft. 



"The stimulating influence of the light as indicated by the growth of plants used in 

 the various tests is shown by the order in which the the sorts are named, the first 

 being the most susceptible: Spinach, cabbage, radish, lettuce, tomato." 



In a study of the periodicity of plant growth as modified by the 

 influence of the artificial light it was found that the most active period 

 of growth of lettuce subject to the influence of the incandescent gas- 

 light began at 11 p. m. and continued until 9 a. m., while with the 

 plants grown under normal conditions the most active period of 

 growth began at la. m. and continued until 11 a. m. In the first 

 instance the period of growth was 10 hours and in the second 7. 



In these experiments no injurious effects resulted from the use of 

 incandescent gaslight. 



The use of chemical fertilizers in the forcing house, W. Stuart 

 {Ame/: Gard., 21 {1900), iVvA 268, 'p. 94)- — This article summarizes the 

 experience of the Indiana Station in the use of commercial fertilizers 

 for forcing lettuce under glass. The results are at variance with those 

 reported ))y A. T. Jordan (E. S. R., 11, p. 1030). the statement there 

 made that '* chemical fertilizers are of little use in the forcing house" 

 being criticised. 



In one test at the Indiana Station the soil used was composed of a 

 black loam sod composted with one-fourth of its ])ulk of manure. The 

 soil to which the commercial fertilizers were applied for comparison 



