22 



JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



acceleration as a result of electrification. Such acceleration may be 

 largely responsible for the increased crop, because by gaining a week 

 upon the weather the plant may mature its grain or fruit under more 

 seasonable conditions. But there is no doubt that such acceleration 

 would mean an earlier arrival of produce on the market for the grower, 

 so that further experiments with this method are of the greatest import- 

 ance for the horticulturist. 



, ^ ^ 5{« ^ ^< ^ ^ ^ ^ 



Forcing by Electric Light. 



This is no new subject; in 1871 Dr. Siemens was reading papers 

 before tht* Eoyal Society upon the use of the electric arc for this 

 'purpose, and in later years the late Mr, Thwaites carried out experi- 

 ments in which travelling lamps were used.* 



These earlier experiments also seem to have shown that the arc 

 light, when not screened by glass, was too powerful for the plant, 

 '-probably too rich in actinic rays, i.e. the rays at the violet end of the 

 spectrum. 



With this in view, when Miss E. G. Dudgeon, of Dumfries, asked 

 my opinion about the use of the Cooper Hewitt mercury vapour lamp 

 for this purpose, I suggested that the lamp would be rather harmful 

 than otherwise because of the preponderance of actinic rays in its radia- 

 tion. Fortunately Miss Dudgeon was not deterred from carrying out 

 the experiment : the Cooper Hewitt lamp was tried, and the results are 

 simply remarkable. Eapid germination and continued rapid growth 

 resulted from the use of the lamp for a period of some two hours every 

 evening after daylight had failed. Miss Dudgeon's experiment is on 

 too small a scale to enable crop yields to be given, but I give her table 

 of germination results more fully than I have done elsewhere. 



Kesults kecoeded by Miss Dudgeon by December 26, 1910. 





Experimental 

 House t 



Control t 



Variety- 













Days taken to 

 germinate 



Days taken to germinate 



French Beans . . 



13 



21 days 



Syrian Beans 



11 



Not germinated yet, planted October 11 



China Beans ... 



9 



>> )j )> 



Soya Beans .... 



11 



" )> >j 





11 



26 days 



Second sowing same week . 



6 





Cauliflower .... 



6 



26 days 



Indian Corn 



8 



57 „ 



Lettuce .... 



6 



12 „ 



Maize . . . • • 



11 



58 „ 



Peas, Laxton's 



7 



16 „ 



Maple Pea .... 



6 



16 „ 



Petersburg Peas . 



" 6 



16 „ 





7 



12 





7 



12 „ 





8 



16 „ 



* Journ. R.H.S. vol. xxxiii. (1908), pp. 401-416. 

 I t Temperature of experimental and control houses about 65° by day and 

 40° to 43° at night, except when sunshine raises temperature. 



