THE MICRO-ORGANISMS PRESENT IN THE ATMOSPHERE. 
145 
No. 1. Flash method. 
Volume of air = 24 litres. 
Construction of plugs .— (a) Glass-wool only. 
(h) Sugared glass-wool and sugar-powder. 
Rate. —8 strokes per minute. (Tube exposed 11 minutes.) 
Colonies in flasks, — (a) 45 j ™ ou ^ s ‘ 
(b) o. iq ‘ 
No. 2. Flash method. 
Volume of air =18 litres. 
Construction of plugs. —( a ) Sugared glass-wool. 
( h ) Sugared glass-wool and sugar-powder. 
Rate .— 6’6 strokes per minute. (Tube exposed 11 minutes.) 
™ 7 . • n i , \ f 19 moulds. 
Colonies in flasks. — (a) 26 j ^ j. 
(b) 0. 
Control-tube, containing plug of sugared glass-wool, exposed 43 minutes :— 
Colonies in flask, 1 mould. 
,. . . . 7 7 7 7 , . fNo. 1 (glass-wool), 19 colonies. 
10 litres of air yielded, therefore, m \. T ^ , 
J J 5 J ’ [No. 2 (sugar-wool), 14 
No. 3. Hesse’s method. 
Volume of air =10 litres. 
„ 7 . . 7 _ ^ f 20 moulds. 
Colonies m tube, 261 
1 1 liq. 
,, control-tube. Lost through spread of liquefying colony, but 
several other colonies were visible. 
VII. Roof of Science Schools. October 22, 1886. Wind S.W., changing to W.; very 
gentle, but variable. Roads wet, roof still wet in places from heavy dew. 
Foggy morning, which had cleared to sunshine. 9°'4 C. 10.44 a.m. to 
11.25 A.M. 
Nos. 1 and 2. Flash method. —(Double plugs.) 
No. 3. Hesse’s method. 
Nos. 1 and 2 were alternated in aspiration. No. 3 was aspirated simul¬ 
taneously in close proximity, the tubes being inclined at the same angle. 
No. 1 . Flash method. 
Volume of air =18 litres. 
Construction of plugs. — (a) Glass-wool only. 
(b) Sugared glass-wool and sugar-powder, 
u 
MDCCCLXXXVII. —E. 
