Action of Dumj and artificial Manures upon Beet-root. 529 
to mc that the answers, if I could obtain them, would be interest- 
ing, and might be useful. To what degree, for instance} one may 
increase the dressing of dung, with corresponding benefit to the 
crop, and what is the limit beyond which an increased quantity of 
dung ceases to act, or again, whether it be better to dress with 
dung only, or with a combination of dung and of artificial manure. 
The latter question is the more practical, because some writers 
maintain that a farm ought to supply its own manure, and that 
the purchase of artificial aids is a proof of imperfect management. 
In order to investigate these and other points, I applied to 5 
acres of yellow globe beet-root, in the first week of April, dif- 
ferent dressings at the following amounts per acre : — 
Duiig. 
Artificial Manure. 
Lot 1. 
26 loads of good dun 
o' 
2. 
13 ditto ditto. 
3. 
13 ditto and . . 
7 cwt. rape-dust. 
4. 
13 ditto and ■ 
14 bush, bones. 
5. 
13 ditto and . 
7J cwt. rags. 
6. 
13 ditto and , 
3 cwt. guano. 
7. 
7 cwt. rape-dust. 
8. 
14 bush, bone-dust. 
9. 
3 cwt. guano. 
10. 
No manure. 
Having found that when manures are tried by being spread 
upon distinct portions of the same field, some uncertainty is cast 
upon the result by differences in the crop, which evidently do not 
arise from the action of the respective manures, but from vari- 
ation in the depth or quality of the soil, from previous manurings, 
from the depredation of insects, or some cause that cannot be 
detected, I apportioned the manures to be tried in a new method, 
which increased the trouble indeed, but which I thought would 
make the result trustworthy. The rows were opened 3 feet apart 
upon the whole piece. In three rows I put the heavy dressing of 
dung ; in the nest two rows, the lighter dressing ; in the two 
following roW'S we added rape-dust to the dung ; and so on until^ 
in 19 ridges, all the trials had been prepared. We then began 
again as before with the heavy dressing of dung, and completed 
another set of 19 ridges like the first. The extent of 5 acres 
allowed 6 sets thus to be made ; which might be regarded as six 
repetitions of the same experiment, and as therefore deserving 
greater confidence. Thus the rows which received artificial 
manure only, of whatever kind, were of a darker green than the 
rest until some hot weather came in August. Their leaves then 
blistered, and many of the leaves withered suddenly off. If 
this had occurred on one patch of ground only, it might have 
