92 Home Produce , Imports, Consumption, and 
wheat, which corresponds to 80 parts by weight of “ wheat-meal 
and flour ” to 100 of wheat. 
The general result of the adoption of the above data, and of 
the slightly altered modes of calculation, has been to make 
changes which are practically immaterial ; but it was thought 
better, on republication, to have the results calculated uniformly 
throughout. 
The population is taken as before ; but, as will be seen 
farther on, the figures will be subject to some alteration for the 
intercensal years, according to corrections subsequently published 
by the Registrar-General. 
It is obvious that the alterations in the calculation of the 
imports, as above described, will slightly, though quite immateri- 
ally, affect the calculations of the amount of wheat available for 
consumption per head from home and from foreign sources re- 
spectively, within each year, and also the sum of the two. 
Appendix-Table I. (p. 132) therefore gives, with what have 
turned out to be immaterial corrections, a complete record of 
the home produce, imports, and consumption, of wheat over 
the forty years of our estimates, so far as already published, 
either in our former papers or in the annual estimates ; and 
before applying to the estimates of the past, the alterations 
or corrections which we have stated will be necessary in the 
future — in accordance with the altered standards recently 
adopted by the Departments in the calculation of cwts. of 
wheat into quarters, and of cwts. of “ wheat-meal and flour ” 
into quarters of wheat, and with the corrections of the popu- 
lation since recorded by the Registrar-General — it will be 
instructive to consider the bearing of the results obtained 
without these alterations, for the period of forty years, as for- 
merly for shorter ones. 
We will first compare in this way the directly calculated 
average produce of the selected experimental plots at Rotham- 
sted, with the annually adopted estimate of the average produce 
of the United Kingdom founded upon them ; and next show 
how far the adopted estimates have been borne out by other 
evidence bearing upon the subject. 
The following Table (I.) shows, for each of the first four eight- 
yearly periods, for the next five years, and for the total thirty- 
seven years, 1852-88 inclusive, — also separately for the last 
three years, 1889-91, and for the total period of forty harvest- 
years, 1852-91, — the produce of wheat per acre, in bushels of 
til lb., as hitherto always reckoned, as under : — 
1. The directly calculated mean produce per acre on the 
selected plots in the experimental wheat field at Rothamsted. 
