876 Agricultu7H(l Gazette of N.S. W. \Nov. 2,'1908. 



Carrots: The two larger were grown with electric stimulus at.the roots ; the other two under 

 ordinary conditions. — From T/if WoM'n WVufc. 



5. Radio culture. 



\ [Anotlier probletn which the Thwaite's and similar experiments throw 

 considei-able light upon is the effect of [colour rays. While red rays 

 stimulate growth very powei'fully, blue rays have a marked retarding 



effect. For the horticul- 

 turist whose greatest 

 trouble is the fluctuation of 

 the market this discovery 

 may prove of great advan- 

 tage. Valuable plantsabout 

 to blossom at an unprofit- 

 able time can be transferred 

 to the blue-ray house, and 

 ictarded for perhaps several 

 weeks until a more favour- 

 able opportunity for dis- 

 posal arises. In order to 

 l)ring about either the re- 

 tarding or forcing result, 

 all that is necessary is to furnish the arc lamp with a screen of the 

 recjuired colour. Probably the retarding colour would be more frecjuently 

 used by floriculturists than the forcing agent. 



Effect of colour rays on young Oak-trees. Both plants are the 

 same age ; that on the left showing fuller foliage and more 

 vigorous growth, especially in the lower part, was grown under 

 red light ; the other under blue light.— From T/ic Wodd's IJ'y/A-. 



