70 EXPERIMENTS UPON WHEAT. [Appendix^ 



The unaided produce of the soil was 25 bushels an acre, and the effect of tlie 

 dressings as follows : — 



Increase. Decrease. 



Guano, 3 cwt 6 bush. — 



Rupe-dust, 5 cwt., sulphate of magnesia, I cwt. . 3^ bush, — 



Sulphate of soda, 1^ cwt., nitrate of soda, | cwt. 1^ bush. 



Common salt, 3 cwt — 3j bush. 



Common salt, 3 cwt., dissolved bones, 1 cwt. . — 2 bush. 



Turnbull's artificial guano produced no sensible effect. 



Under the circumstances, besides being favourable to guano, tlie above re- 

 sult is also in favour of the mixed sulphate and nitrate of soda, which we have 

 seen to operate beneficially upon so many otho: cultivated plants. The entire 

 crop appears to have been injured, not only by ihe summer's drought, but by 

 the severity of the preceding winter. 



In regard to common salt, it is worthy of remark, that the grain dressed by 

 it, whether oats, barley, or wheat, in Mr. Fleming's experiments of this year, 

 has been always heavier per bushel than any of the other samples tried. This 

 accords with the previous results of some other experimenters; but it does not 

 agree with Mr. Fleming's observations upon the wheat of 1841, nor with those 

 of Mr. Burnet for 184"2, and therefore cannot yet be considered as a universal 

 consequence of the application of this substance" as a top-dressing. 



III. The experiments of Mr. Burnet, of Gadgirth, have already been pajtially 

 detailed in tlie text (Lecture XVI., p. 362), and their value explained, Thej 

 are important, chiefly, as showing —  



1°, Economical mixtures. — That mixtures can be prepared which, upon soma 

 soils, surpass guano in efficacy and in economical value, at its former price. 

 The price being now reduced, other experiments are required, yet still the less 

 effect of guano upon the wheat crop is in accordance with the results of Lord 

 Blantyrc. A wet season, however, may alter the numerical relation which 

 daese results exhibit. It will be observed that here also Turnbull's guano pro- 

 duced no sensible effect. 



2°. Effect of soda. — The efficacy of the salts of soda, whether the sulphate, 

 the nitrate, or common salt, upon Mr. Burnet's land, ar^ also vejy striking — 

 half a hundred weight per acre of either producing an additional increase of 

 about 10 bushels of grain. 



3°. YieM of jiour. — Into his tabulated results, Mr. Burnet has introduced a 

 new element, and, as it seems to me, an important one in an economical point 

 of view, namely, the quantity of fine flour yielded by equal loeights of the several 

 samples of grain. The differences presented in this column are veiy striking. 

 Thus 100 lbs. of the greiin reaped from the plot which was — 



Undressed, gave 76^ lbs. of fine flour. 



Dressed with guano 68f lbs. " 



With sulphate of ammonia 66^ lbs. " 



With sulphate of ammonia and nitrate of soda . . . 54f lbs, " 



It would be interesting to learn from an experienced miller to what extent 

 such differences affect the money value of the grain to the manufacturer of 

 flour. 



4°. Amount of gluten. — Through the anxiety of Mr. Burnet to "draw as much 

 information as possible from his excellent experiments, I am able to present 

 another feature in regard to the action of these saline and other substances upon 

 the quality of the produce. 



It is known that the quantity of gluten contained in different samples of 

 flour is very unlike, and that the nutritive property of the flour depends, to a cer- 

 tain extent, upon this quantity of gluten. It has also been stated, as the result 

 of experiment, that the grain which is raised by means of manure containing 

 the largest quantity of nitrogen, is also the richest in gluten. With a view to 

 these questions, Mr. Burnet transmitted to me a pound of each of the sampki 



