.S7A> WILLIAM SIEMENS, I'.R.S. 227 



ited is in a condition to supersede other furnaces for ordinary 

 )ses, the advantages above indicated will make it a useful 

 agent, I believe, for carrying on chemical reactions of various 

 kimls at temperatures and under conditions which it has hitherto 

 IK-CM impossible to secure. (A second charge of steel was now put 

 iuti) the crucible, and was poured out in a molten state at the end 

 of eight minutes.) 



Tin-: EFFECT OF DYNAMO-ELECTRIC ENERQY UPON HORTICUL- 

 TURE, AS A* PROMOTER OF THE CHEMICAL CHANGES BY 

 WHICH THE PLANT TAKES ITS CHIEF INGREDIENTS OF 

 FOOD FROM THE ATMOSPHERE. 



A consideration of the extremely elevated temperature of, and 

 of the effects produced in experimenting with, powerful electric 

 arcs, such as causing blistering of the skin and a feeling akin to 

 sunstroke in the incautious observer, has led me to reflect whether 

 tlu- action of the arc was not analogous to that of the sun in its 

 effect also upon vegetable life. The solar ray, in falling upon 

 the leaf of a plant, not only produces the colouring matter called 

 chlorophyll, but effects within the vegetable cell decomposition of 

 the carbonic acid and aqueous vapour absorbed from the atmosphere 

 for the formation of starch and woody fibre. 



I mentioned my views on this subject to several botanists, from 

 whom I received some encouragement to put the question to 

 practical test, which I accordingly did, commencing in the early 

 portion of the present year, at my country residence of Sherwood, 

 near Tunbridge Wells. 



The apparatus I use consists : 1st, of a vertical Siemens 

 dynamo-machine, weighing 50 kilograms, with a resistance of 

 n-717 unit on the electro-magnets. This machine makes 1,000 

 revolutions a minute ; it takes two horse-power to drive it, and 

 develops a current of from 25 to 27 webers of an intensity of 7(> 

 volts. 2. A regulator or lamp, constructed for continuance 

 currents, with two carbon electrodes of 12 mm. and 10 mm. 

 diameter respectively. The light produced is equal to 1,400 

 candles. :->. A three-horse-power Otto gas engine as motor. 



My object was to ascertain by experiment whether electric light 

 affected the growth of plants. For this purpose I placed in the 



Q 2 



