524 
Journal of Agricultural Research 
Vol. XXIV, No. 6 
considerable work was done with different soaps, i8 in number, the re¬ 
sults were not sufficiently consistent and conclusive to warrant a detailed 
statement concerning them. It seems probable that the product of 
some of the soap factories is not uniform, and the number of brands on 
the market is great and the assortment found in different parts of the 
country varies so much that it seemed inadvisable to attempt to study 
them fully. However, it may at least be said that some quite con¬ 
sistently give bad results with the arsenicals and others are relatively 
harmless, while still others are variable. The brand most used in this 
investigation^^ was rather consistent and intermediate in its effect 
upon the arsenicals. 
Soap appears to have some effect also upon the injurious properties 
of the soluble arsenical compounds, as shown in Table XII. This tend¬ 
ency is in general toward reduction when soap is added, but it is not so 
marked as to have great significance. Perhaps the more even spread 
on the leaf surface would account for it. 
Tabl^ XII.— Effects of soap on the burning properties of soluble arsenical compounds 
Soluble ai:seixical compounds to which 
^ soap was added. 
Number 
of appli¬ 
cations. 
Number 
of times 
injury 
increased. 
Number 
of tim^ 
injury 
decreased. 
Number 
of times 
injury was 
the same. 
Number 
of times 
there was 
no injury 
with or 
without 
soap. 
Arsenic acid. 
9 
O 
4 
3 
I 
Ammonium arsenate. 
7 
O 
2 
3 
2 
Cacodylic acid. 
3 
O 
O 
3 
O 
Potassium arsenate. 
7 
O 
4 
o 
3 
Potassium arsenite.. 
8 
I 
3 
4 
o 
Potassium cacodylate. 
5 
2 
I 
I 
I 
Sodium arsenate . 
lO 
O 
3 
3 
4 
Sodium arsenite . 
9 
I 
2 
4 
2 
Sodium cacodylate . 
. 
5 
o 
I 
2 
2 
UMK-SUnPHUR AND TOBACCO EXTRACT 
It may be at times desirable to add both lime sulphur and tobacco 
extract to lead arsenate or other arsenical spray mixtures, provided the 
efficiency of neither is destroyed and the resulting mixture is not danger¬ 
ous to foliage. 
Table XIII.— Effects of lime sulphur and tobacco extract on the burning properties of 
various arsenical compounds 
Arsenical compotmds to which lime 
sulphur and tobacco extract were 
added. 
Number 
of brands. 
Number 
of appli¬ 
cations. 
Number 
of times 
injury 
incieas^ 
Number 
of times 
injury 
decrease. 
Number 
of times 
injury 
was the 
same. 
Number 
of times 
there was 
no injury 
with or 
without 
soap. 
Arsenic trioxids. 
I 
2 
0 
0 
0 
2 
Calcium arsenites. 
I 
lO 
0 
7 
2 
I 
Copper aceto-arsenite. 
I 
i 6 
7 
I 
4 
4 
Ferrous arsenites. 
1 
2 
I 
0 
0 
I 
Lead arsenates, triplumbic.... 
4 
38 
^9 
0 
0 
19 
Lead arsenates, diplumbic. 
9 
S8 
25 
I 
0 
32 
Lead arsenates, mixture. 
6 
12 
12 
0 
0 
0 
Zinc arsenite.. 
2 
30 
10 
4 
0 
16 
“ Diamond C.” 
