402 
Field Experiments on Potatoes. 
The average produce of the crops of 1867 were considerably 
less than those of the two preceding years, partly resulting from 
a late frost in the end of May having somewhat injured the tops 
just appearing above ground, and it is probable that the experi- 
ments may not be as reliable as under more favourable circum- 
stances. 
It will be observed that the produce of the individual experi- 
ments in the several twelve sets of trials vary considerably. 
With a view to ascertain their general bearing, the following 
comparisons are made, and the average result of the 12 trial 
plots of eacli of the seven experiments placed in their relative 
order of productiveness. 
Two of the 12 trial plots were carried out with 8 oz. sets. 
Three „ „ 6 „ 
Four „ „ 4 „ 
Three „ „ 2 „ 
Averaqe Produce per Acre. „ 
•' ^ Tons cwts. qrs. lbs. 
12 Plots of No. 4.-4 cwts. mineral superphosphate audj 14 7 ^ 24' 
4 cwts. crude potash-salts .. .. / ^ 
„ No. 1.— No manure 12 12 0 7i 
„ No. 6.— 4 cwts. crude potash-salts .. .. 12 10 1 
„ No. 7. — 4 cwts. common salt 12 8 2 5j 
„ No. 2. — 4 cwts. mineral superphosphate ..12 2 1 8 
„ No. 3.— 20 tons rotten dung 11 14 3 15^ 
„ No. 8. — 4 cwts. mineral superphosphate and| 9 9 q 
4 cwts. of common salt .. .. / 
It will be noticed that the' unmanured plots produced a teavy 
crop of potatoes, which was only exceeded by the produce of the 
plots manured with mineral superphosphate and potash-salts. 
It is worthy of remark that the produce of the ground enriched 
with 20 tons per acre of rotten dung falls somewhat short of that 
in which no manure was used. Furthermore, attention deserves 
to be directed to the slight variations in the average produce of 
all the plots except those manured Avith mixed mineral super- 
phosphate and crude potash-salts. 
The whole tenor of these experiments appears clearly to indi- 
cate that the trials were made in too rich a soil, and the details 
of these experiments, which are not altogether void of interest, are 
reported as a striking example, showing how mucb careful 
labour is thrown away in a great measure when manuring expe- 
riments are carried out on land in too high a condition of agri- 
cultural productiveness. 
Potato Experiments made in 1868 bij Messrs. Coleman and Hull, 
Escricli Park, York. 
Early in 1868 I issued a circular, in which amongst other 
experiments I recommended the following : — 
