EXPERIMENTAL FARMING. 349 



when it is most sensibly felt. It would probably be found to 

 be the greatest during the four warmest months of the year, 

 and most perceptible in the night, especially when there is a 

 liability to frost. 



11. The potato disease deserves to be made the subject of 

 experiment by every association connected with agriculture. 

 It is time that every farmer tries more or less experiment, either 

 incidentally or for the purpose of obtaining information on the 

 subject. But their experiments are not the result of concerted 

 action, and are seldom based on a sound, inductive method. A 

 farmer in the town of A. may be engaged this year in expensive 

 trials, which have been repeatedly made without success by 

 farmers in the town of B. On a public farm such experiments 

 might be conducted on the most philosophical principles, — the 

 experimenters having the advantage of suggestions from scien- 

 tific and practical men throughout the world. 



Though it is not probable that an absolute cure or prevention 

 of the potato rot will be discovered, we may, perhaps, by a 

 series of experiments conducted on true inductive priuciples, 

 learn the means of keeping the potato comparatively free from 

 disease. We should inquire : What kinds of soil are the most 

 favorable, and what kinds are most unfavorable to the sound 

 conditi-on of the potato ? What is the influence of a greater 

 and .a less amount, than an average of dryness or humidity ? 

 Is there any chemical application that would lessen the evil 

 effects of moisture, if excessive moisture be one of the secon- 

 dary causes of the disease ? Does the potato remain more 

 exempt from the rot, in a sandy, or in a calcareous soil, of 

 equal humidity ? Is there any kind of soil that is uniformly 

 favorable or unfavorable to its soundness ? Does a virgin soil 

 produce a sounder crop than one that has been freely composted ? 

 What are the effects of different kinds of compost, of the dif- 

 ferent modes of distributing it, and of small or profuse quanti- 

 ties ? 



Above all, is the potato disease contagious ? If contagious, 

 may it not be communicated by growing the potatoes in a soil 

 in which diseased potatoes were raised on the preceding year ? 

 Might it not also be communicated by using compost, in which 

 some of the diseased tubers had been mixed ? This appears to 

 be a very probable conjecture. If the disease be contagious, it 

 45 



