532 Experiment on the Elementary Principles of Manure. 
heavy crop of Swedes, all drawn oft'; and the whole field was top-dressed in 
April with 1 cwt. of nitrate of soda and 1 cwt. of salt per acre, given in two 
applications, at a fortnigrht's interval, 1 acre near the centre of the field having 
been left undressed. This and the adjoining acre have been thrashed, and 
yielded as follows : — 
£. s. d. 
1 acre, with nitrate and salt, 42 bushels, worth 6s. 6<f. .. 13 13 0 
1 acre, without manure, 30 bushels, worth Gs. 6cf 9 15 0 
3 18 0 
Cost of manure — 1 cwt. nitrate, 18s. ; 1 cw t. salt, 2s. .. 10 0 
Profit per acre 218 0 
In my own experiment the produce, it will be seen, is very 
low. Besides the gradual impoverishment of a naturally poor 
soil, the cutting winds of a harsh sjiring had almost blown the 
plants out of the soil, and had rendered the wheat in May almost 
invisible. But in a more sheltered part of the same field the 
result, as proved by a separate threshing, was greatly better. 
Nitrate. Salt. Yield in Wheat. 
2^ acres ... 3 cvvt. 4 cwt. 65 bushels. 
Being at the following rate, — 
Nitrate. Salt. Cost of Manure. Yield. ' 
1 acre . . .135 lbs. 180 lbs. 23s. 26 bush. 
For the sixth white crop in six years from the same field this 
result is certainly very respectable, being not far from the average 
produce of wheat land in England, 
In conclusion, I am well aware that the only novelty in this 
experiment consists in its negative results, that is, in the in- 
efhcacy of certain chemical elements on the growth of the wheat 
plant. Still negative results are not altogether useless in map- 
ping out for future investigators the unexplored fields of science, 
and may therefore, when carefully made, be placed on record for 
their service. 
Even the positive result may serve also as one proof among 
many of the benefits of top-dressing. In some neighbourhoods 
this already ranks as an established practice. Thus in a Norfolk 
corn-dealer's circular, certainly a very practical testimony, I find 
it stated, "The yield of wheat has so gradually increased during 
the last few years, mainly through the use of artificial manures 
used as top-dressings^ that it is difficult to define what is an 
average crop." Yet over the greater part of England probably no 
one would say that this practice^ even if known, has become an 
ordinary act of husbandry. If it be permitted to advert to the 
cultivation of our French neighbours and friends, no one who 
has seen the farming of their northern departments will doubt 
that the practice would be preeminently useful there. They 
