106 MR. SOLLY ON THE 



the growth of these beds of potatoes no difference whatever was 

 perceptible at any period on the most careful and rigid compari- 

 son. Towards the ripening of the tubers, those in all the beds 

 were attacked by the prevailing rot ; it took them comparatively 

 late, and but slightly ; this effect, however, was not peculiar to 

 those which were the subject of electric experiments, as there 

 was no difference between them and the standard bed. The 

 tubers were taken up in the middle of October, when the fol- 

 lowing was the produce of the respective rows. Each row was 

 fifty feet long. 



standard. Long pendent Buried and short 



Mean ... 82 89 81 



The difference between the three beds was very small therefore, and 

 quite within the ordinary limits of accidental difference, because, 

 though it is true that the mean of the second bed is rather higher 

 than either of the others, yet we see that even in that bed tlie 

 produce of the four rows varies as much as 31 lbs., whilst in the 

 third bed it varies 31 lbs., and in the standard 39 lbs. The re- 

 sult of this experiment therefore, like that with the barley, appears 

 decidedly opposed to the idea of atmospheric electricity exerting 

 any strong influence on the growth of plants under ordinary cir- 

 cumstances. 



In order to ascertain the effects of feeble galvanic currents on 

 the germination of seeds and subsequent growth of young plants, 

 the following experiments were made : a slip of zinc plate, 2 

 inches by 6, was connected by a wire with a plate of copper of 

 tlie same size, and placed in the earth, the edges just appearing 

 above its surface, at a distance of eight inches ; eighteen grains 

 of barley and the same number of wheat were then sown in two 

 straiglit lines between the plates, and a similar series were also 

 sown close by, without any plates ; all other conditions were as 

 like as possible : the result of this experiment was — 



5tli Day. 6th Day. Tth Day. 8th Day. 



Plates. Without. Plates. Without. Plates. Without. Plates. Without. 



Wheat .2 8 1 12 7 18 18 



Barley .5 3 18 15 18 18 18 18 



In another similar experiment with twelve seeds of wheat alone, 

 in which the plates were buried below the surface, and placed 

 horizontally edge to edge, with little more than a quarter of an 

 inch between their edges ; on the sixth day ten had come up 

 between the plates, and but six without thera. These experi- 

 ments, however, though they certainly seemed to confirm the 



