414 Field Experiments on Potatoes. 
7. Very small weak tops, and of a pale yellow colour ; appa- 
rently the poorest plot of all. 
8. Good strong heal thy plants, and very regular in the rows. 
9. Plants very regular, and appearance about the same as 
Plot 4. 
A casual observer could readily distinguish the plots upon 
which nitrogenous manures had been used from the others, by the 
dark green colour which the potato-tops on these plots presented. 
On the other hand, he would at once recognise the parts of the 
field to which potash-salts, and especially common salt, had 
been applied, by the pale green colour of the tops. 
The plots manured with potash-salts did not look very promising 
at first, but they subsequently recovered and yielded a good 
increase, although the tops throughout the whole period of 
growth were paler in colour than on the unmanured portions of 
the field. On the plot which had received 4 cwts. of salt, in 
addition to 4 cwts. of superphosphate, the potatoes made no way, 
looked pale and sickly, and yielded only an inconsiderable 
increase over the unmanured plots. 
For the sake of better comparison the increase of each plot 
over the average yield of the unmanured portions of the field has 
been calculated in the following tabular statement : — 
Table XIV. — Showing the Increase of each Manured Plot per Acre over the 
average yield of the Unmanured portions of the Potato-field at Escrick 
Parlj Home-farm, 1869. 
Plots. 
Name or Mahube. 
i 'Mineral Superpliosphate 
Crude Potash-salts 
and 
Sulphate of Ammonia . . 
Kotten Dung 
{Mineral Superphosphate 
and 
Potash-salts 
i Mineral Superphosphate 
Potash-salts 
and 
Nitrate of Soda .. .. 
Peruvian Guano .. 
j Mineral Superphosphate 
< and 
(Common Salt 
Rotten Dung 
Increase of ftoduce 
per Acre. 
Tons cwts. lbs. 
13 84 
13 
17 
18 
15 
10 
84 
54 
44 
4 
20 
100 
Average produce of unmanured plots, G tons 1 1 cwts. 68 lbs. 
A glance at the preceding table shows: — 
1, That the greatest increase was obtained by applying to the 
