25 
EXPERIMENT NO. 3. 
Formalin-permanganate method. 
Formalin, 600 c. c. 
Permanganate, 300 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, 0.0353 gram. 
(Determination made by drawing air from the room, beginning 15 minutes after mixing the 
formalin and permanganate and consuming 1 hour 15 minutes in the drawing.) 
Yield of formaldehyde, 33 per cent. 
Weather: Strong wind from the southwest; clear. 
Tempera- 
ture. 
Relative 
humidity. 
Absolute 
humidity 
(grams per 
cubic foot). 
Before mixing HCHO and KMnOi _ 
° F. 
77.5 
78.0 
78.0 
Per cent. 
72 
87 
81 
7.28 
8.94 
8.30 
After 10 minutes 
After 1 hour 
See Note, Experiment No. 1. 
[4- means growth; — no growth.] 
EXPERIMENT NO. 4. 
Formalin permanganate method. 
Formalin, 600 c. c. 
Permanganate, 300 grams. 
Capacity of room, 2,000 cubic feet. 
Quantity of formaldehyde used per cubic foot, 0.107 gram. 
Quantity of formaldehyde liberated, undetermined. 
Weather: Cloudy; light westerly winds. 
Tempera- 
ture. 
Relative 
humidity. 
Absolute 
humidity 
(grams per 
cubic foot). 
° F. 
Per cent. 
Before mixing HCHO and KMnO^ 
78 
75 
7.70 
After 10 minutes 
78 
91 
9.34 
After 2 hours 
78 
91 
9.34 
See Note, Experiment No. 1. 
