The Stourbridge Observer, Cradley Heath, Halesowen & District Chronicle.
Stourbridge, West Midlands, England, 1875-02-27 00:00:00

LECTURE ON "VENTILATION."

At a meeting of the chemical section held in London
on Friday evening in last week, at the Society of Arts,
under the presidency of Dr. Odling, F.R.S., a lecture
was delivered by Mr. W. N. Hartley, F.C.S., on the
subject of ventilation. He set out by briefly describ-
ing the chemical composition and properties of the
atmosphere, and then went on to enumerate the
various gaseous matters which occur in it as impurities,
confining his remarks chiefly to that which, owing to
its incessant production by combustion and respiration
—viz., carbonic acid—is found in a more or less dif-
fused state throughout its volume. The presence of
this gas in the expired breath—of which it was stated
to form five per cent.—as well as its production by the
combustion of carbonaceous matters in the air, were.
practically demonstrated by simple and striking expe-
riments, and its physiole /ical effects when inhaled,
and its inability to suppol• t the respiratory process in
the lungs, were prominently alluded to. The neces-
sity of getting rid of its presence in our rooms was
thence deduced, and the comparative inefficiency of
the ventilation provided by the ordinary fireplace and
chimney without any outlet for the exhausted air in
the upper part of the chamber made clearly apparent.
The theory of the construction of up and downcast
shafts in coal mines was also explained by means of
suitable models. The lecturer then went on to define
ventilation, not simply as the supply of fresh air, but
the supply of fresh air without draught, a process
which was constantly taking place even in closed
rooms by means of diffusion through the porous sub-
stance of the walls and ceiling. The average percen-
tage by volume of carbonic acid was given as about
0.4, while in crowded workshops it had been found to
reach 18, and in mines the average amount was some-
thing like 18 per cent., the highest quantity allow-
able in pure and wholesome air being 'O6. The result
of analyses of the air of crowded theatres showed the
presence of large quantities of this oppressive gas,
sometimes to the extent of .22 per cent. The average
quantity of carbonic acid respired per hour by one
man was 6 10ths of a cubic foot, and consequently one
person sleeping in a room would require a supply of
3,000 cubic feet of fresh air per hour in order to dilute
his breath sufficiently to render it innocuous to his
own system, for in the human breath was given off, in
addition to the carbonic acid, a quantity of poisonous
organic matter. For ventilating large buildings, the
lecture • was inclined to advocate the use of rotating
fans. In the course of his final remarks, he spoke of
the importance of the proper construction of drain
pipes laid below the foundations of houses, since as
much of the " fresh " air supplied to our rooms passed
through the soil, any leakage might seriously contami-
nate the air for breathing purposes, and so produce
disease.

A short discussion followed the lecture, and a vote
of thanks to Mr. Hartley and to the Chairman brought
the meeting to a close.