October, ’24] 
de ong: colloidal sulfur for red spider 
535 
Table i—Properties of Colloidal Sulfur Solutions 
Method of 
Dates of Observation 
Preparation 
May 16 May 17 May 19 May 28 
(first day) 
Grains Microns Grains Microns Grains Microns 
Saturated solution 
of sulfur dioxid 
plus hydrogen sul¬ 
fide, 7.3 gm. sulfur 
per liter 
Solution yel¬ 
low, very few 
crystals, 
homogene¬ 
ous, no visi¬ 
ble particles 
18 
25 
25 
A few 
gates 
17 
2-7 
1-2 
aggre- 
4 
8 
9 
A few 
gates 
17 
8-17 
2-7 
aggre- 
13 8-17 
50 2-7 
No aggregates 
Unsaturated solu- 
Homogene- 
1 
8 
3 
8 
1 
8 
tion of sulfur diox- 
ous, no visi- 
33 
1.5-8 
50 
1-8 
50 
1-9 
id plus hydrogen 
ble particles 
50 
1-2 
150 
1-2 
100 
1-2 
sulfide, 5.2 gm. sul- 
A few large 
(barely 
A few large 
fur per liter 
aggregates 
visible) 
crystals 
Lime sulfur solu- 
White, ho- 
1 
8 
9 
8 
Yellow precipi- 
tion,5 gm. per liter 
mogeneous, 
5 
1-8 
30 
1-8 
tate 
plus 5 gm. glue 
very fine 
75 
1 
6 
1 
1 
8 
Ppt. with hydro- 
particles 
A few 
aggre- 
3 
2-6 
chloric acid 
gates 
25 
i 
Lime sulfur solu- 
Heavy pre- 
50 
8 
tion,5 gm. per liter 
cipitate 
100 
1-8 
plus 1 gm. gelatine 
25 
1 
Ppt. with hydro- 
Numerous 
chloric acid 
aggregates 
Sulfur flour 92 per 
6 
26 
cent passing a 200- 
14 
17-26 
mesh screen 
39 
8-17 
64 
7-8 
than large grains both as fungicides and as acaricides then such prepara¬ 
tions must be more active than the finest of ground or flowers of sulfur 
now in use. These fine particles soon aggregate, however, and in a few 
days may contain many particles similar in size to the better grades of 
sulfur now on the market. It should be noted, however, that these 
larger particles formed after a few days do not represent all the sulfur 
present so that there may still be a large proportion of finely divided 
sulfur too small to be seen at the magnification at which these measure¬ 
ments were made. Various materials were tried as stabilizers but glue 
and gelatine gave the best results. The best results being obtained by 
