No. VIII.] EXPERIMENTS UPON POTATOES, 65 



a better price in the market — but by the ordinary modes of cull'uie is the least 

 productive of those generally cultivated. It would then be not only an interest- 

 ing, but an important economical question to ask — could this variety be render- 

 ed more productive by a different mode of treatment — one especially adapted to 

 its own nature 7 Would the practical man not rejoice to think that such a result 

 could be brought about by the aid and suggestions of science 1 Yet this is the 

 result to which the refined series of experiments suggested by the question 

 abov^e proposed may possibly lead. 



May I venture to hope that some of my more zealous readers will be induced, 

 during the present or succeeding summer, to make trials of the relative effects 

 of the same saline or other known substances and mixtures, upon different varie- 

 ties of the same crop — of potatoes, turnips, wheat, &cc., in circumstances other- 

 wise equal, in some such form as the following : 



Variety A. Variety B. Variety C. Variety D. Variety E. 



Substances. Substances. Substances. Substances. Substances. 



A. I B. I C. A. I B. I C. A. I B. I C. J^- | ». | C. A. | B. | C. 



The results if carefully ascertsiined are sure to lead to good, if they should 

 not be successful at once in solving the problem above proposed. 



3°. Solidity and size of the potatoes. — Nothing is said in the observation of 

 Mr. Fleming, or his overseer, in regard to the size or solidity of the different 

 varieties of potato, or of the different samples of the same variety on which the 

 experiments were made. Yet in connection with the remarks 1 have already 

 offered upon these qualities of the turnip, it is proper to add that the potato is 

 subject to similar variations in the proportion of water it contains — and, there- 

 fore, in the relative amount of nourishment capable of being afforded by equal 

 weights of its different varieties. 



Some potatoes contain less than 70, others upwards of 80 per cent, of water, 

 so that while 100 tons of one sample will give only 20 tons of nourishment, the 

 same weight of another will give 30 tons, or one half more. In general, such 

 as grow on heavy or clay soils, or such as are less ripe, contain the most, while 

 those which have been planted upon sandy spots, or are fully ripe, contain the 

 least water. But the effect produced by different soils we tsegin now to 

 see may be produced by different methods of dressing or medicating our crops 

 also. 



Suggestion VI. —It would be interesting to determine, therefore, by actual 

 experiment, the relative proportions of water contained in the produce of the 

 several experimental patches of potato ground upon the same field, when 

 equally ripe, or when dug up on the same day. This would afford us the 

 means of approximating-^still more closely to the true econojnical action of our 

 different manures upon the potato crop. It may turn out that in certain cases 

 the increase of produce, as indicated by a greater weight, is only apparent, 

 while the increased amount of food raised may in other cases be considerable, 

 though the balance indicates no increase of weight. 



Did we know the relative proportions of water in the several samples of the 

 three varieties of potato raised by Mr. Fleming by the aid of guano, and of 

 rape-dust, already compared together, our conclusion in regard to their relative 

 productiveness, when treated by either substance, might be materially altered. 

 I hope, therefore, that this point also will hereafter arrest the attention of some 

 of our experimentalists. 



4°. Permanent effects of saline manures on tlve future productiveness of the 

 seed. — Recommending to my practical readers a careful consideration of the 

 effects of an admixture of wood-ashes with the several dressings applied to the 

 turnip and potato crop, I pass on to the two following series of experiments 

 with saline manures upon the potato crop, as given on p. 49. These two series 

 are well conceived, and the results veiy instructive. Of these results the one 

 which seems to me most deserving if the attention of the practical man is con- 



