No. /X] REMARKS UPON PRECEDING EXPER'iMENTS. 83 



cwt. of dry nourishment. It may be, therefore, that as by growing in unlike 

 soils or with unequal degrees of rapidity our potatoes may contain different pro- 

 ponious of water, so by different kinds of dressings which act in the same way 

 as natural differences of soil, and cause the plants to develope themselves with 

 greater or less rapidity, the same effects may be produced. One kind offline 

 substance, such as nitrate of soda, by hastening the growth, may give us a crop 

 of potatoes containing much water, while another, such as sulphate of soda, by 

 retarding the growth, may give a crop containing less water — and thus, though 

 tnere may be no difference in the weight of the two crops, they may be very 

 unlike in the relative proportions of food they contain. 



If such be the case it is of great practical importance to determine the quantity 

 of water which our several experimental potato crops contain, since without 

 this we may draw very incorrect conclusions as to the value of our experimental 

 manures — placing the highest value upon that which gives the greatest weight 

 of raw material, and esteeming least, perhaps, that which produces the greatest 

 weight of dry food 



1 would again, therefore, draw the attention of my readers to the subject of 

 Suggestions IV. and VI., [Appendix, pp. 63 and 65,] in reference to the deter- 

 mination of the quantity of water in their experimental root crops. The 

 method of doing this is very simple, and has already been described, [Appendix, 

 P- 64.] , 



Each new series of experimental results we are called upon to examine and 

 analyse, will, I hope, more and more satisfy my readers, as they do myself, 

 that this is the true line of procedure, and that though there may be much in 

 our results at first which may appear contradictory and discouraging, yet that 

 out of these crude results, when combined, compared, and frequently repeated, 

 the real substance of a rational agriculture will, slowly it may be and with dif- 

 ficulty, yet surely at last, be extracted. 



No. X. 



RESULTS OP EXPERIMENTS IN PRACTICAL AGRICULTURE, MADE 

 AT B.\ROCHAN IN 1843. 



Experiment I. — Upon Potatoes. 



Comparative effects of guano, farm-yard manure, gypsum, &c., by them- 

 selves and in- mixture, upon Potatoes of different varieties, planted 25th, 26th, 

 and 27th April; lifted, measured, and weighed from 12th to 14th October, 

 1843. On one-eigJdh of an imperial acre. 



The portion of the field upon which these potatoes were grown contains 

 about five acres ; soil — loam of medium texture, super-incumbent upon trap 

 rock. It was trenched with the spade out of seven years old lea in the winter 

 of 1812 and 1843 to the depth of 16 inches, the sward bein^ turn-spaded into 

 the bottom of the trench, and the subsoil a stiff yellow tril brought up to the 

 top, which mouldered down to a fine mould during the winter. The drills were 

 formed for the potato cuts with the double-moulded plough, and by the 7th 

 June the plants were all brairded in the rows, and were worked in the usual 

 manner with the plough, drill, grubber, and hand-hoes. After the drills were 

 formed, where the guano was used, it was sown in the drills by the hand, on 

 the bottom and sides of the drills, the farm-yard manure being then put in and 

 30* 



