s
the respired air from the lungs to be removed, but also the deleterious
exhalations from the skin which are produced by perspiration.

The allowance of 40 cubic feet per head per minute should not, if
properly distributed, cause an unpleasant draught in any part of the hot
rooms; for it must be remembered that even in a highly-heated atmosphere
a waft of air of the same temperature is felt to be cold. The main thing
to be studied in this provision of a large volume of air is that the
cold inlet be ample, and the passage from this intake to the point
where the air is debouched into the laconicum equally roomy and
unobstructed. The rapidity of flow will depend upon the means provided
for the extraction of the foul air. With large horizontal flues, and a
capacious and tall shaft, the so-called natural system of ventilation
will be as effective as could be desired. Greater extraction power is
gained if in the brick stack a smoke-pipe can be placed running up the
whole height. In many cases mechanical ventilation could be employed
with the greatest benefit. A powerful air-propeller fixed at the end of
a system of horizontal flues under the floors of the hot rooms, and
running so as to exhaust, would do away with all the objectionable
odours and nastiness of many baths.

The purity or foulness of the air in the hot rooms forms all the
difference between a good bath and a bad one, which latter is infinitely
worse than no bath at all. There exist, at the present time, scores of
baths where the odours of the sudatory chambers are nauseating. Such
foulness arises from stagnation of the air. There is no continuous flow,
and the respirations and exhalations of the bathers are not removed. A
system of ventilation may be pointed out, but it is on the wrong
principle, and does not act. There is no change of air. The atmosphere
of such places becomes pestilential.

Owing to the expansion by heat, a relatively greater volume of air
enters the laconicum than the cold intake. This fact, however, does not
practically affect the arrangements for ventilation, &c. Theoretically,
however, it would seem to demand that the shaft conducting from furnace
to hot rooms should be of greater sectional area than that to the
furnace from the intake--about one-third larger--and that the total area
of outlets for the escape of vitiated air should be about midway between
the two.

The whole principle of the ventilation of the hot rooms of a Turkish