ELECTRICITY ON VEGETATION. 



45 



fiours a day, from ten till twelve in the morning, and from four 

 till six in the afternoon ; the experiment was commenced early 

 in July and continued till nearly the middle of August, and the 

 weather being remarkably fine and warm, the machine worked 

 well and gave abundance of electricity. In the middle of 

 August the working of the machine was discontinued, the plants 

 were all then perfectly similar, and during the whole time of 

 carrying on the experiment no perceptible difference could be 

 observed in any of the pots. 



The general result to be drawn from these four experiments 

 made on different kinds of plants is certainly opposed to the idea 

 of much influence being exerted by free electricity on the growth 

 of plants under ordinary circumstances. It is very possible that 

 the arrangements devised for the purpose of these experiments 

 were by no means the best, or those most fitted to exalt the 

 effects sought for, but nevertheless a number of seeds and young 

 plants were placed four hours a day under the influence of an 

 unusual quantity of negative and positive electricity, and it is 

 hardly possible to doubt that some effect would have been 

 apparent were the free electricity of the earth and air of so 

 much importance in connection with vegetation as has been 

 supposed. 



VIII. — A Return of the Proportion per Acre of Diseased and 

 Sound Tubers in the Society's Collection of Potatoes culti- 

 vated in 1846. By Mr. R. Thompson, Superintendent of the 

 Orchard and Kitchen-Garden Department. 



A considerable number of varieties of potato in the Society's 

 collection had been cultivated in the garden for many years. 

 A change of soil became necessary ; this, as well as want of 

 space in the garden, rendered it expedient to plant out most of 

 the varieties on a farm in the neighbourhood belonging to Mr. 

 Jessop. This season the following varieties were thus treated, 

 near the Thames, in a warm, black, sandy soil, loose for the 

 roots of plants both in wet and in dry weather. It had no 

 manure, as the latter appears to increase disease in the present 

 over-excitable state of the potato plant. 



The potatoes were planted in drills, about 21 inches apart. 

 The length of drill which each variety occupied was accurately 

 measured, and the produce carefully weighed, even to ounces. 

 From the data thus obtained the following table has been com- 

 puted : — 



