April, ’24] 
headlee: dusts for stored seed insects 
303 
Table 7. 
No. 
Name of Carrier Si0 2 
Fe 2 OA:Al.A 
CaO 
MgO 
pH 
Loss on 
07 
/o 
% 
% 
C7 
70 
ignition 
1 
Highland Clay 52.59 
33.25 
0.95 
0.22 
7.5 
10.50 
2 
3 
Bond D Clay" 68.00 
Mill town Ball Clay 
21.90 
0.30 
0.20 
7.0 
8.00 
No. 
9 63.30 
13.80 
0.22 
0.16 
4.7 
10.88 
3A 
Milltown Ball Clay 63.30 
13.80 
0.22 
0.16 
4.7 
10.88 
4 
Calcium sulfate 0.02 
0.00 
41.14 
0.00 
7.5 
5 
Sea vSand 98.04 
1.02 
0.03 
0.40 
7.0 
0.70 
These same materials were mixed with common white beans and seeded 
with ten 
adult beetles each. 
The results ; 
are set forth 
in the following 
table:— 
Table 8. 
No. 
Acid 
Alka- Neu- 
Material used 
No. of 
No. of 
reac¬ 
line tral 
Dust 
Amt. 
Amt. 
beans 
Adults 
tion 
reac- reac¬ 
beans 
Dust 
pene¬ 
tion tion 
grms. 
grms. 
trated 
1 
Highland Clay 
10 
1 
none 
10 
2 
+ Bond D Clay 
10 
1 
none 
10 
3 
+ 
Milltown ’ 
Ball Clay No. 9 
10 
1 
none 
10 
3A 
+ 
Milltown Ball Clay No. 9 
10 
1 
none 
10 
4 
+ 
Calcium sulfate 
10 
1 
24 
68 
7 
Check 
10 
18 
(< 
8 
Check 
10 
22 
80 
Thus it seems obvious that chemical composition, acidity and alkalin¬ 
ity have little, if anything, to do with the effectiveness of the dusts 
when used in comparatively low dilutions (one part of dust to ten 
parts of beans). 
Physical Characters 
The physical characteristics of the dusts were next examined. The 
clays were, of course, more colloidal than either the calcium sulfate or 
the sea sand. A study of the comparative colloidal character of the 
three clays used is set forth in the following table, which serves to show 
that Milltown Ball Clay No. 9 is the most colloidal of them all: 
No. Carrier 
Table 9. 
Flocculation 
Turbidity meas¬ 
measured by 
measured by 
ured by residue 
transparent 
sedimentation 
in soil susre"s : on 
1 Highland Clay 
liquid 
2 
16 
(salts included) 
124 
2 Bond D Clay 
2 
65 
242 
3 Milltown Ball Clav No. 9 
j 
2 
75 
246 
mesh 
