57 
One thousand c. c. of commercial methyl alcohol were placed in the 
reservoir of the lamp and 1,500 c. c. of water in the basin around the 
reservoir. 
In a preliminary experiment it was found necessary to have two 
silver nitrate tubes to absorb the hydrocyanic acid which was carried 
over from the cyanide absorption tubes by the air bubbling through 
them. This was no doubt due to the presence of a relatively large 
amount of carbonic acid and perhaps a small quantity of formic acid. 
While formaldehyde is formed by the action of the platinized asbes- 
tos in the lamp, it is more than likely that it is not the only product of 
oxidation, but that the oxidation extends as far as the formation of 
carbonic acid. It is known that formic acid is oxidized to carbonic 
acid by platinized asbestos. The presence of either carbonic or 
formic acid in the air bubbling through the cyanide absorption tubes 
would cause the liberation of some hydrocyanic acid, which would be 
carried over. The precipitate in the first silver nitrate tube was some- 
what greater than in the case of the other methods. The precipitate 
in the second silver nitrate tube did not appear until toward the end 
of the experiment. 
The chemical determinations were made as follows : 
I. Began to draw air 2 hours after lamp was started; volume of air drawn, 10 liters; 
time required, 1 hour 13 minutes; condition of wind, gentle breeze. 
Temperature of room before experiment, 79° F.; relative humidity, 87 per cent. 
Temperature of room 2 hours after starting lamp, 85° F.; relative humidity, 98 per cent. 
Formaldehyde found per cubic foot, 0.01096 gram. 
II. Began to draw air 2 hours after starting lamp; volume of air drawn, 10 liters; time 
required, 1 hour 6 minutes; condition of wind, moderate breeze. 
Temperature of room before experiment, 75° F.; relative humidity, 82 per cent. 
Temperature of room 2 hours after starting lamp, 92° F.; relative humidity, 96 per cent. 
Formaldehyde found per cubic foot, 0.00986 gram. 
In another experiment, which was done during colder weather than 
the above, the following are the results : 
III. Began to draw air 2 hours after starting lamp; volume of air drawn, 10 liters; time 
required, 1 hour 15 minutes; condition of wind; light breeze. 
Temperature of room before experiment, 42° F.; relative humidity, 69 per cent. 
Temperature of room 2 hours after starting lamp, 49° F.; relative humidity, 86 per cent. 
Formaldehyde found per cubic foot, 0.00424 gram. 
As the formaldehyde is derived from methyl alcohol it is impossible 
to make a comparison of the percentages of formaldehyde obtained 
by this method with those obtained by the other methods in which 
formalin is used instead of alcohol. 
Germicidal properties . — In all but two of the experiments the organ- 
isms were placed in the wire trays in the room before the lamp was 
started and the time of exposure estimated from the moment of start- 
ing the lamp and closing the room. This appeared to be the most 
rational way of estimating the time of exposure, as the lamp was in 
