New York xIgricultural Experiment Station. 309 
tuiirrigated. The seed used was the White Star variety, except the 
first row, which was a red-skinned seedling free from scab. A dry 
season made the conditions very favorable for this experiment. Irri- 
gation was begun July 19, when the tubers had just commenced to 
form, by allowing a small stream of water to run during the hours 
from 6 p. m. to 7 a. m. between two of the four hills extending across 
the whole number of rows. This was continued until October 15, at 
which time each hill of potatoes was dug separately, each tuber 
examined for scab, and a record made of the whole number of tubers 
and the number of scabby tubers. 
Twenty-two rows were planted with scabby tubers, and twenty- 
three with tubers entirely free from scab, in the following manner: 
First row, a red-skinned seedling free from scab, then two rows of 
scabby tubers of the White Star variety, next two rows with tubers of 
same variety free from scab, and so on alternately two rows scabby and 
two without scab. The tubers of each four rows thus planted were 
treated with a different substance intended as a preventive of the scab, 
which will be shown in the table that follows. The twenty-two rows 
on the south end of the planting were manured with stable manure 
before plowing the land. 
TABLE A. 
Scabby Seed. 
Smooth Seed. 
IRRIGATED. 
UNIRRIGATED. 
IRRIGATED. 
UNIRRIGATED. 
to 
U 
TREATMENT. 
CD 
ft 
© . 
CO 
X2 
CD . 
X2 p 
>» 
,0 
fit 
eg 
B © 
B CD 
X2 
rO 
<S 

§•2 

ole n 
of tu 
SD 
f 
ole n 
of tr 
CO 
1 
ole n 
of tu 
Ct. Si 
nf fn 
OQ 
+-i 
O 
xi 
3 
U 
Xi 
f-i 
© 
Ph 
Ph 
w 
Unmanured. 

Untreated 
19 
84 
21 
47 
33 
Hyposulphite of soda 
"'9 
' 56 
55 
-16 
66 
27 
42 
Sulphate of iron 
80 
22 
116 
22 
77 
12 
81 
18 
Sulphate of copper 
Mercury chloride 
28 
7 
41 

4 

21 

92 
23 
111 
15 
92 
5 
85 
10 
Salicylic acid 
112 
40 
111 
54 
101 
25 
77 
23 
Carbolic acid 
55 
.29 
34 
9 
59 
8 
97 
18 
Manured. 
100 
49 
123 
41 
125 
56 
139 
19 
Muriate of potash 
83 
83 
104 
33 
65 
80 
84 
20 
25 
Sulphate of potash 
82 
58 
84 
26 
98 
63 
79 
Air-slaked lime 
104 
89 
105 
22 
89 
80 
76 
50 
78 
87 
77 
90 
59 
85 
105 
86 
Untreated.— Ordinary culture, smooth seed, 279 potatoes ; 163 scabby, or 58.4 per cent. 
Comparing the irrigated with the unirrigated portion, the following 
result is obtained: 
