Experiments on the Growth of Potatoes. 161 
The Wimborne kidneys are very good, but the ash-leaf kidneys 
have failed in a manner similar to what is described in Lot 4. 
Lot 8. Potatoes from Mexico, cut in two parts ; growing vigorously 
and well. 
Lot 9. Potatoes from New Grenada; also growing well, but not so 
strong as Lot 8. 
You shall be informed of the produce of each lot when they 
have been harvested. 
Yours truly, 
Bryanston, June 18, 1846. Portman. 
XL — On the Advantages or Disadvantages of Breaking up Grass 
Lands. By John Bravender, F.G.S., Surveyor, Cirencester. 
Prize Essay. 
Down Land. 
It might be assumed that, because one person may have obtained, 
with artificial manures, an excellent crop of wheat from a thin 
down soil, all such land ought therefore immediately to be broken 
up and cropped with wheat ; but this would not be a fair mode 
of testing such a step. The wheat crop is only one of a course, 
and before the farmer can place the least faith in anv calcula- 
tions, the expenses and produce of the entire course must be laid 
before him. Some of the crops of such course are not paying 
crops, and these should be balanced against those that pay. Or 
if we take the first crop of wheat only, and assume that we shall 
always obtain the same quantity, we may discover too late that 
we have difficulty in obtaining the same amount of produce 
again. Hence we must ascertain what would be the probable 
produce continuously, under proper cultivation, when the first 
flush of the soil has vanished. To settle our notions on this 
subject, if they are wavering, let us make the inquiry. Would 
it be advisable to break up all the chalk downs in England ? — 
My reply would be, " I think not."' Those which are much 
elevated, or very thin, would not bear corn crops, except at 
long intervals. Those not too much elevated, would produce 
sainfoin, and perhaps vetches and turnips, and a corn crop now 
and then, but would possibly pay better in down, depastured, 
as now, by sheep folded on the arable land at night. If such 
lands, after being broken up, could not be maintained as arable, 
it would be a great mischief to have broken them up at all, be- 
cause years would be required to restore even such scanty sward 
as our downs now produce. I should therefore hesitate to re- 
commend the breaking up of land very much elevated, or of very 
VOL. VII. M 
