ELECTRICAL EXPERIMENTS 395 



"After a few weeks' growth a casual look down the green- 

 house showed the effect of radiation on the growth of the 

 plants, those within the six-foot area being considerably 

 in advance of those outside it. 



" I saved nine different varieties of seeds, and the 

 quicker germination of those seeds under the mercury- 

 vapour lamp in comparison with the control ones was 

 remarkable, as the following table shows : 



Kind. Days in Expert- Days in Control 



mental Set. Set. 



French Beans . 13 21 



Carrots .... n 26 



Cauliflowers ... 6 26 



Maize .... 8 57 



Lettuce .... 6 12 



Peas 6 16 



Oats 7 12 



Barley .... 7 12 



Wheat .... 8 16 



" I kept a careful register of the temperature in both 

 houses daily, and from time to time took the soil tem- 

 perature. There was never a full degree difference in 

 the latter. On days when we had bright sunshine the 

 control-house temperature rose slightly higher than that 

 of the experimental, owing to its being more exposed to 

 the sun during a short time in the day. The following 

 is the average temperature of both houses for three 

 months : 



Experimental. Control. 



Max. Min. Max. Min. 



January ... 50 deg. 46 deg. 59 deg. 48 deg. 

 February . . 60 ,, 44 ,, 67 ,, 50 ,, 

 March 73 ,, 47 ,, 78 ,, 50 



" Except on sunny days the average day temperature 

 was from 50 to 63 degrees in both houses. In January 



