THE MICRO-ORGANISMS PRESENT IN THE ATMOSPHERE. 
131 
Fig. 3. 
Experimental Results obtained by Flask Method. 
In the first instance a number of experiments were made with tubes containing 
only a single plug, the construction of which was varied for purposes of comparison. 
Single Plug Experiments. 
I. Laboratory window (same as above). September 18, 1886. Wind S.E., strong, 
variable in strength and direction. No recent rain. Roads watered in street 
below. ] 5 0, 1 C. 
No. 1 . Time. —11.40 a.m. to 12.10 p.m. 
Volume of air =30 litres. 
Construction of plug. —Sugared glass-wool and sugar-powder. 
Rate. —3'6 strokes per minute. 
^ . n i f89 moulds. 
Co tomes in flask, 1311 .. 
J l 0 lap* 
Control-tube containing plug of sugared glass-wool.—Colonies in flask, 0. 
No. 2. Time. —12.26 p.m. to 1.3 p.m. 
Volume of air =30 litres. 
Construction of plug. —Sugared glass-wool and sugar-powder. 
* liq. = Colonies causing liqiiefaction of tlie gelatine. 
s 2 
