88 
PROF. T. CARNELLEY, MR. J. S. HALDANE, AND DR. A. M. ANDERSON 
4. Effect of Dust and of the Stagnation of the Air. —An atmosphere which has been 
entirely at rest for some time contains less organic matter than it did previously. This, 
however, is not necessarily due altogether to the settling down of solid organic dust 
(though dust materially affects the determinations), but is probably ow T ing in part to 
oxidation. The effect of stagnation, and thence of settling, and possibly of partial 
oxidation, was shown by the following results :— 
Organic matter. 
Second experiment. 
Air of dark cellar which had been kept closed 
for some time. 
9-4 
Outside air at same time. 
132 
Air-tiglit room after being well ventilated witb 
outside air and then closed for three days . 
4-9 
Outside air on third day. 
9 - 5 
Same room after ventilation with outside air . 
3-2 
17 
Ditto, after being closed for two days . . j 
Too small to 
estimate 
Too small to 
estimate. 
Ditto, after ventilation with outside air . . 
17 
Ditto 
Same room after five persons had been in the 
room for f-h° ar with the door closed 
Ditto, after the room had been closed for two 
32 
days. 
17 
Organic matter in outside air at end of period 
17 
A similar effect is also shown in the case of the large sewer under the Houses of 
Parliament. This sewer forms a cul-de-sac at the end by the Victoria Tower, whence 
it runs the whole length of the building to the Clock Tower, where it joins the 
Metropolitan sewer. Before the recent alterations, this sewer was ventilated by 
suction, caused by a furnace at the bottom of the Clock Tower. Practically, therefore, 
this suction was pulling against what tended to become a vacuum ; the effect being 
that, though there was a good draught by the Clock Tower, the strength of the air- 
current gradually diminished as the blind end of the sewer was approached, so that 
near the Victoria Tower end no draught was perceptible. Here the air remained 
stagnant. Suspended organic matter would thus settle down, and in consequence of 
this and of oxidation there would be an increase in carbonic acid, accompanied by a 
diminution in the organic matter, as we pass from the Clock Tower end to the Victoria 
Tower end of the sewer. This is shown as follows :— 
