McLeod. — Effect of Electricity on Plant-groivth. 479 



Akt. LXV. — The Effect of Current Electricity upon 



Plant-growth. 



By H. N. McLeod. 



[Read before the Hatvke's Bay Pliilosophical Institute, 28th November, 



1892.] 



In experiments which have been conducted on this subject 

 great success seems to have been attained with electricity of a 

 high intensity, such as is produced by the common frictional 

 machine. Plants are very good conductors of electricity in 

 this state, as is shown by several experiments. A vegetable 

 joint, when tied to the knob of a Leyden jar, was found to 

 discharge it in less than half the time taken by a metallic 

 point ; and when a sprig of a certain shrub was tied to the 

 knob of an electroscope, the leaves were affected at three and 

 a half times the distance that they were when wire points 

 were substituted. A blade of grass will show a luminous 

 point while being withdrawn from the prime conductor of a 

 frictional machine, long after a needle has ceased to glow. 



Mr. Pine, of Maidstone, using Leyden jars filled with 

 earth, and keeping one charged with negative and another 

 with positive electricity, found that seeds which were planted 

 in the negatively-electrified jar germinated more rapidly and 

 grew faster than some which were planted in the positively- 

 electrified jar ; while seeds which he planted at the same time 

 in an unelectrified jar were two days later in appearing, and 

 did not grow as rapidly. 



Monsieur Grandeau, at Nancy, and Monsieur Le Clerc, at 

 Mettray, in France, found atmospheric electricity to have a 

 marked effect on the seed- and flower-producing powers of 

 grain- and tobacco-plants; but opposite results were obtained 

 in the experiments of Monsieur C. Naudin. 



A Mr. Weeks applied electrified water to seeds, which 

 appeared above the ground sooner, and grew with much greater 

 vigour, than seeds watered with an equal amount of unelectri- 

 fied water. 



In one of the supplements to the Scientific American of 

 some months back this experiment on a large scale was de- 

 scribed, and the trial was a decided success. 



Vegetables grown under the electric light were found to 

 mature in one-third less time than it took vegetables which 

 were not exposed to the electric light. This was proved at 

 Home, in England, just recently. 



The method of applying the electric current in most of the 

 following experiments was by connecting the poles of an 



