THE MICRO-ORGANISMS PRESENT IN THE ATMOSPHERE. 
139 
VII. Roof of Science Schools. October 13, 1886. Wind W. by S.W., strong, but 
constant. Much rain during day and night previous. 10°*6 0. 4.47 r.M. to 
5.30 p.m. Comparison between glass and sugar plugs. Tubes alternated in 
aspiration. 
No. 1. Volume of air =24 litres. 
Construction of 'plugs. — (a) Sugared glass-wool. 
( h ) Sugared glass-wool and sugar-powder. 
Rate. —5 strokes per minute. (Tube exposed 17 minutes.) 
„ 7 . . „ 7 . , „f'22 moulds. 
Cotomes m flasks. — (a) 381 
(h) 0. 
0 liq. 
No. 2. Volume of air =27 litres. 
Construction of plugs. — (a) Glass-wool only. 
(b) Sugared glass-wool and sugar-powder. 
Rate. —7‘2 strokes per minute. (Tube exposed 14 minutes.) 
„ 7 . . f 39 moulds. 
Colonies m flasks. — (a) 61 j 
(b) o. 1 '■ 
Control-tube, containing sugared glass-wool plug, exposed 46 minutes: — 
Colonies in flask, 0. 
No. 1 (sugar-wool), 16 colonies. 
10 litres of air yielded, therefore, in 
No. 2 (glass-wool), 23 
VIII. Roof of Science Schools. October 14, 1886. Wind W. by S.W. Moderate. 
Constant in direction. Roads wet, pavement dry. 4.8 p.m. to 4.56 p.m. 
12 0, 2 C. Comparison between glass and sugar plugs, 
aspiration. 
Tubes alternated in 
No. 1. Volume of air = 24 litres. 
Construction of plugs. — (a) Glass-wool only. 
( b) Sugared glass-wool and sugar-powder. 
Rate. —6 - 6 strokes per minute. (Tube exposed 13 minutes.) 
Colonies in flasks.—(a) 44 j 23 mou],ls - 
1 0 liq. 
1 mould. 
0 liq. 
No. 2. Volume of air = 24 litres. 
Construction of plugs.—(a ) Sugared glass-wool. 
(b) Sugared glass-wool and sugar-powder. 
Rate. —5 strokes per minute. (Tube exposed 16 minutes.) 
T 2 
