338 Home Produce, Imports, Consumption, 
The Area under Wheat. — For the period from 1852 to 1865 
inclusive, we had to rely on estimates alone in fixing the area 
under the crop in England and Wales. For Scotland, we had 
Returns collected by the Highland Society for the years 1854, 
1855, 1856, and 1857 ; but for the two years prior to 1854, and 
for the years subsequent to 1857, down to 1865 inclusive, Ave had 
to rely on estimates merely. For Ireland, Returns were available 
for each of the sixteen years included in the inquiry. Thanks 
to the exertions of Mr. Caird, we have for 1866, and for each 
year since, an official record of the area under the crop, in each 
division of the United Kingdom, and in the whole collectively, 
in the ' Agricultural Returns ' now annually published about the 
time of harvest. One element of uncertainty in any estimates of 
the home produce of wheat is, therefore, fortunately removed. 
The Average Yield of Wheat jier Acre. — The only Returns or 
official estimates at command relating to this subject, were for 
Scotland for four years, and for Ireland for each year within the 
period of our inquiry ; whilst, for England and Wales, com- 
prising from 85 to 90 per cent, of the total area under the crop, 
there was, and there is, no official information whatever. For 
this large proportion of the United Kingdom it was therefore, 
after very full consideration of the data, and of the results to 
which they led, decided to adopt the average produce per acre 
each year, on certain selected, and very differently manured 
plots, in the permanent experimental wheat-field at Rothamsted, 
as the basis of estimates of the average produce per acre from 
year to year ; and, each year since, the same data have been 
relied upon in forming an estimate of the average produce over 
the United Kingdom as a whole. But, having regard to the 
character of the soil at Rothamsted, to the characters of the indi- 
vidual seasons, and to the consideration whether the season was 
more favourable for heavy or for light land, and so on, the 
estimate actually adopted for the country at large has, in some 
seasons, and more especially in bad seasons, differed somewhat 
from the actual average indicated on the selected plots in the 
experimental field. Lastly, in all cases, the actual number of 
bushels is reduced by calculation, so as to represent bushels of 
the standard weight of 61 lbs. per bushel. 
It is proposed, on the present occasion, briefly to examine into 
the validity of the data thus taken as a basis for estimating the 
average yield per acre of the country each year, and also into the 
trustworthiness of the results arrived at, as tested by subsequent 
knowledge, and by their accordance, or otherwise, with the con- 
clusions arrived at in regard to other elements of the question. 
The Aggregate Home Produce, and the Amount of it available 
for Consumption. — It will be obvious that, if we know the area 
