252 THE SCIENTIFIC PAPERS OF 



the engines by compressed air, and he had nothing to say against 

 it, but it did not do away with the necessity of having an engine 

 nearly as heavy as the present locomotive. He believed if electric 

 transmissions were tried on that railway in such a way as to make 

 the rails act as the return conductor, making them all " earth," 

 and fixing guide rails under the roof for the conveyance of the 

 current, to be taken into each carriage by means of a metallic 

 rope, great certainty of action would be obtained, and the trains 

 would be propelled through the tunnel at a very economical rate, 

 and without fear of their being stopped midway. These were the 

 features of this innovation ; that it lent itself to the conveyance 

 of power to any reasonable distance, and that it could be applied 

 without any of those inconveniences which now beset our loco- 

 motive traffic. He hoped that before long a trial would be made 

 of the system, not, perhaps, on a very large scale at first, but 

 sufficient to show its merits. 



ON SOME APPLICATIONS OF ELECTRIC ENERGY TO 

 HORTICULTURE AND AGRICULTURE. 



By C. WM. SIEMENS,* D.C.L., LL.D., F.R.S., Mem. Inst. C.E. 



ON the 1st of March, 1880, I communicated to the Royal 

 Society a paper, " On the Influence of Electric Light upon 

 Vegetation, &c.," in which I arrived at the conclusion that 

 electric light was capable of producing upon plants effects 

 comparable to those of solar radiation ; that chlorophyll was pro- 

 duced by it, and that bloom and fruit rich in aroma and colour 

 could be developed by its aid. My experiments also went to 

 prove that plants do not as a rule require a period of rest during 

 the twenty-four hours of the day, but make increased and vigorous 



* Paper read before Section A of the British Association, 1st September, 1881, 

 and ordered to be printed in cxtenso among the reports. Journal of the British 

 Association for the Advancement of Science, 1881, pp. 474-480. 



