words, they exhibit symptoms peculiar to plants grown in the dark. 

 Their leaves possess no texture nor healthy green color, their petioles 

 are small and elongated, their fruit is often stunted in its growth and 

 shows lack of color, and the plant's degree of maturity is not what 

 it would be if grown under better light conditions. We have seen 

 instances in cucumber houses where plants which had been shaded 

 for a few hours each day by some adjoining building showed a loss 

 of 50% in maturity. At the Station greenhouse we obtained differ- 

 ences ranging from \o'^lc to 80% in the maturity of cucumber plants 

 caused by exposures to single, double and triple layers of glass. A 

 diagrammatic .sketch of such a house is shown in fig. 5. It will be 



Fig. 5, showing: longitudinal and cross sectii)ns of greenhouse with partitions running 

 east and west, and illustrating the effect of poor light conditions. 1 he oblique lines repre- 

 sent the path of the sun's rays. 



noticed that at one end of the house where the plants are small the 

 sun for a part of the day in winter had to pass through three layers 

 of glass, namely, one roof and two glass partitions ; while at the 

 other end of the house the cucumber plants obtained their light 

 throughout the day with only one layer of glass intercepting. The 

 difference in the development of these plants is very striking, and, 

 although the sketch is diagrammatic, the variations are no greater 

 than occurred in the house under these conditions. The two scales 

 and figures upon the side show the relative differences in the matu- 

 rity of the plants, — the one to the left gives the loss due to 

 inferior light conditions. In some cases, however, this loss was 



