64 EXPERIMENTS UPON POTATOES, [Appendix^ 



sizes from each sample — cutting a slice from either side, and one from the mid- 

 dle of each turnip — weighing the whole — drying them then, first in the air, 

 afterwards before a gentle fire, and lastly in an oven so hot as not to brown white 

 paper or dry flour, and then weighing. The loss being the weight of the water 

 m the turnips, will enable the experimenter to determine the relative quantities 

 of food raised upon his different plots, and therefore the relative value of his 

 different applications or methods of culture. 



In this suggestion the re*ler will perceive another of those precautions which 

 the prosecution of our experimental inquiries renders necessary — future years 

 will suggest others — but the increase of trouble will not deter the zealous la- 

 bourer in this important field — for the more precautions and difficulties multiply, 

 the greater the honour will be to those who by perseverance shall successfully 

 overcome them. 



B. — The Experime7ds upon Potatoes. 



Nearly all the experiments in the first table of results (p. 48) were made with 

 mixed manures. 



1°* Chiano and rape-dust. — Among these the effect of guano is again striking, 

 and upon two of the varieties gi-eatly exceeds that of rape-dust. Thus, the pro- 

 duce of the three varieties tried was — 



Unaided soil . 

 "With 3 cwt. guano . 

 With 4 cwt, guano . 

 With 1 ton of rape-dust . 12 



We are not enabled, by the experiments before us, to compare its effect with 

 that of farm-yard manure. 



A curious question suggests itself upon the inspection of the above numbers 

 — one which could scarcely have arisen in our minds, had not differences such 

 as the above presented themselves among the results of our experiments. 

 Nothing is more common than to ask which of several varieties of potato is the 

 more prolific — and a practical man who has made the trial has no difficulty in 

 giving an immediate answer to the question. But the experiments of Mr. Flem- 

 ing seem to say that the relative iceight of crop yielded by each of tico or more va- 

 rieties of potato, depends upon the icay in which you treat or manure them. With 

 one treatment a variety (A), with another a variety (B), will give the heaviest 

 crop. Thus, our three varieties gave with — 



White Don. Red Don. Connauglil Cups. 



Natural guano . 18 tons 9 cwt. 14 tons 6 cwt, 13 tons 14 cwt, 

 Rap^dust . . 12 " 6 " 10 " " 13 " " 



Both substan«es agree in saying that the whit^. is considerably more prolific 

 than the red Don. But while the guano adds that both Dons are more prolific 

 than the Cups, tlie rape-dust pronounces the latter variety to be superior to either 

 of the former. Now it may have happened tliat in the last case of the three, the 

 rape-dust, from some circumstance not noticed, may have acted better than in 

 the other two cases, and that in this way the discordance may have arisen. Un- 

 fortunately, however, there are upon record no other experiments made upon 

 any two of the varieties of potato with otlier substances used in Uke proportion 

 — By which t||^ question might have been in some measure solved. But the 

 interesting, and as it may hei-eafter prove, important inquiry suggests itself—- 

 what is the order of relative productiveness of the several varieties of the same culti- 

 vated plant, when they are severally dressed or manured vdth this or with that sub- 

 stance? This question will, no doubt, hereafler lead to extended series of very 

 refined experimental inquiries, from which not only much knowledge but much 

 practical benefit may be derived. 



Suggestion V. — It may be, for instance, that a given variety of potato, turnip, 

 oat, barley, &c,, is more valuable as food, more agreeaole tc the taste, or bring* 



