46 EXPEKIMENTS \VITEI EEFEEENCE TO THE TOTATO DISEASE. 



XII. — Account of Experiments made in the Garden of the 

 Horticidtural Society, in 1847, laith reference to the Potato 

 Disease. By Robert Thompson. 



(Nov. 15, 1847.) 



Various remedies having been suggested for the mysterious 

 disease which has so extensively affected the potato crop, it was 

 resolved that a number of experiments should be made, in order 

 to try the efficacy of these proposed remedies, in tlie Garden of 

 the Society. 



A piece of ground was accordingly appropriated of as uniform 

 quality as possible. It formed a parallelogram, 32 feet wide, 

 open to sun and air, and was not manured. 



In the experiments of which the results are given in Table I., 

 the sets, cut tubers, were uniformly planted in rows across the 

 above-mentioned compartment, the rows being 2 feet 4 inches 

 apart, and running in the direction of north and south. The sets 

 were planted 7 inches deep, and 8 inches from plant to plant in 

 the rows. The variety of potato employed was the Jersey Blue, 

 excepting for rows 11 and 12, in which young tubers of the 

 Ash-leaved Kidney were planted ; and the two half rows Nos. 

 37 and 38 were planted with the Cornish Kidney, the sets of the 

 Jersey Blues having been exhausted. The following are the 

 particulars of the respective experiments : — 



1. Lime and Charcoal. — The results are given in Table I., 

 Nos. 1, 2, 3. The quantities for the 3 rows were 1 bushel of 

 lime, and J^ bushel of powdered charcoal, mixed and scattered 

 along the drills previously to planting the sets. This mixture 

 was at the rate of 194 bushels of lime and between 9 and 10 

 bushels of charcoal per acre. The average sound produce of 

 these three rows exceeded that of the adjoining three, to which 

 nothing was applied, by 3 tons 13 cwt. 55 lbs, per acre. This 

 surplus, it will be observed by referring to the table of results, 

 is entirely owing to the enormous produce of the first of the 

 three rows to which the mixture of lime and charcoal w^as 

 applied, for the produce of the other two is below the average. 

 In these the produce of sound tubers is respectively at the rate 

 of 12 tons 18 cwt. 91 lbs. and 11 tons 7 cwt. 63 lbs. per acre; 

 whilst that of row No. 1 is 20 tons 4 cwt. 110 lbs. This dif- 

 ference of produce cannot be ascribed to the mixture applied, for 

 of this each row had an equal share. It can only be accounted 

 for by the circumstance of the row No. 1 being at the outside, 

 running parallel with a gravel walk, in consequence of which 

 the foliage had more light and air, with full exposure to the 

 afternoon sun. It is further worthy of remark, that whilst this 



