60 EXPERIMENTS WITH KEFERENCE TO THE POTATO DISEASE. 



Sulphuric acid 1 part to 25 parts of water. — Table Y. 2. 

 The quantity of sulphuric acid to a row of 22 feet in length 

 was 1 pint in 25 pints of water, being at the rate of 106 gallons 

 of sulphuric acid, and 2650 gallons of water per acre. In this 

 experiment the general appearances were similar to those exhi- 

 bited in the preceding; but the stems and foliage were not de- 

 stroyed to so great an extent. The produce, however, was 

 nearly -g-V less than where double the quantity of acid was em- 

 ployed. In this, as in the other case, there were no diseased 

 tubers. 



Sulphuric acid 1 jjart to 50 parts of water. — Table V. 3. 

 Quantity to a row \ pint in 25 pints of water, estimated per 

 acre, 53 gallons sulphuric acid, and 2650 gallons of water. The 

 stems and foliage were less injured by tlie acid than in the pre- 

 ceding case. In tlie course of a week after the application, not- 

 withstanding the partial destruction of the foliage, the roots 

 emitted healthier fibres and runners than those of plants to 

 which nothing was applied. At the end of June, roots of 

 healthy appearance were even proceeding from the part of the 

 stem between where the acid had decomposed the bark at and 

 a little under the surface of the ground, and where the bark 

 was quite dead from disease next the old set. The quantity of 

 sound produce was at the rate of 6 tons 10 cwt. 29 lbs. per acre. 

 The diseased portion was scarcely 4 per cent, of the whole 

 produce. 



Sulphuric acid 1 j^ait to 100 parts of tvater. — ^Table V. 4. 

 Quantity to a row \ pint in 25 parts of water. Estimated quan- 

 tity per acre 26 l gallons of sulphuric acid, and 2650 gallons of 

 water. Tiie foliage, compared with that in the preceding rows, 

 was injured in a less degree than tliat corresponding with the 

 ratio in which the acid was ajiplied. Yet many of the leaves 

 were partially burned. The effects of the acid were more espe- 

 cially manifested round the margins of the leaflets. But the 

 peduncles and calyces appeared in all cases most readily affected 

 by the application. Even at this degree of the •dilution, the pe- 

 duncles drooped, and the calyces turned red in a few hours after 

 the application, and next day became brown. The amount of 

 sound produce was upwards of a ton per acre above that of the 

 preceding experiment ; but the per-centage diseased was also 

 greater, being fully equal to that of the row which had nothing. 



Sulphuric acid 1 part to \oO parts of icater. — Table Y. 5. 

 Quantity to a row \ pint, in 25 pints of water. Estimated 

 quantity per acre, 17 gallons 5 pints of sulphuric acid, and 2650 

 gallons of water. Compared with the preceding, the foliage was 

 still less injured. Sound produce increased nearly to the esti- 

 mated amount of a ton per acre ; but fully as much as 11 p*er 

 cent, of the total produce was diseased. 



