33 
EXPERIMENT NO. 10. 
Dilute formalin-permanganate method. 
Formalin, 600 c. c. 
W ater, 600 c. c. 
Permanganate, 450 grams. 
Capacity of room, 2,000 cubic feet. 
Quantity of formaldehyde used per cubic foot, 0.107 gram. 
Quantity of formaldehyde found per cubic foot, 0.0279 gram. 
(Determination made by drawing air from the room, beginning 16 minutes after mixing the 
formalin and permanganate, and consuming 1 hour 12 minutes in the drawing.) 
Yield of formaldehyde, 26.1 per cent. 
Weather: Light east wind, cloudy. 
Tempera- 
ture. 
Relative 
humidity. 
Absolute 
humidity 
(grams per 
cubic foot). 
Before mixing HCHO and KMnCL 
° F. 
80 
81 
81 
Per cent. 
74 
91 
91 
8.09 
10.82 
10.26 
After 10 minutes 
After 2 hours 
See note, Experiment No. 9. 
[+ means growth; — no growth.] 
Organism. 
B. coli communis . 
B. subtilis 
B. pyocyaneus . . . 
B. dysenteric 
B. coli communis. 
B. subtilis 
B. coli communis. 
How exposed 
5 
10 
20 
30 
60 
120 
Glass 
do 
Filter paper 
do 
+ 





do 
+ 
do 
Wilson method 
+ 
+ 
- 
- 
- 
- 
Time of exposure in min- 
utes, and results. 
EXPERIMENT NO. 11. 
Dilute formalin-permanganate method. 
Formalin, 600 c. e. 
Water, 300 c. c. 
Permanganate, 375 grams. 
Capacity of room, 2,000 cubic feet. 
Quantity of formaldehyde used per cubic foot, 0.107 gram. 
Quantity of formaldehyde found per cubic foot, 0.03517 gram. 
(Determination made by drawing air from the room, beginning 21 minutes after mixing the 
formalin and permanganate, and consuming 47 minutes in the drawing.) 
Yield of formaldehyde, 32.87 per cent. 
Weather: Light breeze, cloudy. 
Tempera- 
ture. 
Relative 
humidity. 
Absolute 
humidity 
(grams per 
cubic foot). 
Before mixing HCHO and KMnO^ 
0 F. 
79 
79.5 
80 
Per cent. 
79 
94 
89 
8.38 
10.10 
9.57 
After 10 minutes 
After 2 hours 
See note, Experiment No. 9. 
