AIR AND VENTILATION.

Globe, Volume III, Issue 295, 22 May 1875, Page 3

AIR AND VENTILATION.

At a recent meeting of the Chemical Section of the Society of Arts, under the presidency of Dr Odling, F.R.S., Mr W. N. Hartley, of King's College, gave a lecture on "Air and Ventilation." The lecturer, in the course of his remarks, pointed out that too much carbonic acid in the atmosphere vitiated it, and this acid was produced largely by the personal heat and breath of living creatures. Air once used in respiration was unfit for combustion or further, respiration until it was again renewed by a copious mixture with fresh air. _ This fact showed the necessity of ventilation either natural or mechanical ventilation not simply a supply of fresh air, but fresh air free from draught. Air came through the walls of a house or room, and, entering in that way, was free from draught, and this source of ventilation was especially useful in winter, when the cold necessitated the doors and windows being shut. The nose was a very good test for indicating the presence of a polluted atmosphere, for when the nose was offended by a disagreeable closeness the air was more or less vitiated by carbonic acid and organic matter. The proper proportion of carbonic acid was six volumes in 10,000 cubic feet. All crowded buildings were naturally subject to vitiated air from carbonic acid. The law courts were always famous for being filled with foul air because sufficient air was not given for each person present. The air at some of the theatres had been analysed, and the atmosphere of the boxes was often as bad as that of the gallery. Between the acts the air was usually very bad, because when the curtain was down the supply of fresh air was cut off, for it mostly came from behind the scenes. In buildings in which large audiences assembled natural ventilation required to be supplemented by mechanical means, and at present the best means for ventilating buildings was that used in an American hospital. It was a rotating fan, which drove the air through pipes, to be distributed throughout the hospital. In summer the air was passed over ice to cool it. and in winter over hot water pipes to warm it, and when used was allowed to find its way out as it could. In England it was not advisable to change the air of a room more than four or five times an hour, and when moving at the rate of 19 inches per second it did not produce any draft—in fact, it was unfelt. There was one other point to be noticed. There was much carbonic acid in soil, and it should not be allowed to pass from the soil into houses. If the air in the soil was polluted by air escaping from a drain it might, and probably would, pass into adjacent houses with very disastrous results. It was therefore highly important that attention should be drawn to this fact, and he trusted his lecture would result in calling attention to this matter, which was of the highest importance.