636 TRANSACTIONS OF 3ECTION I. 
In a destroyer visited by me twelve men occupied quarters containing about 
1,700 cubic feet of air. There was a stove with iron pipe for chimney, from 
which fumes of combustion must leak when in use, and a fan which would not 
work. When the men are shut down the moisture is such that boots, &c., go 
mouldy, and the water drips off the structure. The cooling effect of the sea-water 
washing over the steel shell of the boat is beneficial in keeping down the 
temperature in these confined and_ ill-ventilated quarters. On the 
maneuvring platform in the engine-room the wet-bulb temperature reaches 
a very high degree owing to the slight escape of steam round the turbines. 
Commander Domvile was kind enough to send me the wet and dry bulb tempera- 
tures taken there on a number of days. The wet bulb was found to be never 
below 80° F., sometimes reached 95° and even 98° F. It is impossible for officers 
to work at these temperatures without straining the heat-regulating mechanism 
of the body and diminishing their health and working capacity. 1f such wet-bulb 
temperatures are unavoidable, means should be provided, such as fans, which 
would alleviate the discomfort and fatigue caused thereby. A supply of com- 
pressed air fitted with a nozzle might be arranged and used occasionally to douche 
the body with cool air. I have tried this plan and found it very effectual, and 
can recommend the compressed-air bath as the substitute for a bracing cold wind. 
The suitability of the clothing is of the greatest importance, not only to the 
comfort but to the efficiency of man as a working machine, e.g., power of soldiers 
to march. On a still day the body is confined by the clothes as if by a chamber 
of stagnant air, for the air is enclosed in the meshes of the clothes and the layer 
in contact with the skin becomes heated to body temperature and saturated with 
moisture. 
The observations of Pembrey show that himself and four soldiers, marching 
in drill order on a moderately warm day, lost more water and retained more 
water in their clothes than on another similar day when they worked with no 
jacket on. The average figures were loss of moisture 1,600, against 1,200 grms., 
and water retained in clothes 254, against 109 grms. With no jacket the pulse 
was, on the average, increased 28 against 41 in drill order, and rectal tempera- 
ture 1° against 1°°5 F. The taking off of the jacket or throwing open of the 
jacket and vest very greatly increase the physiological economy of a march. It 
is absurd that on a hot summer day Boy Scouts should march with a coloured scarf 
knotted round their necks. Nothing should be worn for ornament or smartness 
which increases the difficulty of keeping down the body temperature. The power 
to march and the efficiency of an army depend on prevention of heart stagnation 
and avoidance of fatigue of the heart. 
I conclude, then, that all the efforts of the heating and ventilating engineer 
should be directed towards cooling the air in crowded places and cooling the bodies 
of the people by setting the air in motion by means of fans. In a crowded room 
the air confined between the bodies and clothes of the people is almost warmed up 
to body temperature and saturated with moisture, so that cooling of the body by 
radiation, convection and evaporation becomes reduced toa minimum. ‘The strain 
on the heat-regulating mechanism tells on the heart. The pulse is accelerated, the 
blood is sent in increased volume to the skin, and circulates there in far greater 
volume, while less goes through the viscera and brain. As the surface tempera- 
ture rises, the cutaneous vessels dilate, the veins become filled, the arteries may 
become small in volume and the blood-pressure low, the heart is fatigued by the 
extra work thrown upon it. The influence of the heat stagnation is shown by 
the great acceleration of the pulse when work is done and the slower rate at which 
the pulse returns to its former rate on resting. 
The increased percentage of carbonic acid and diminution of oxygen which has 
been found to exist in badly ventilated churches, schools, theatres, barracks, is 
such that it can have no effect upon the incidence of respiratory disease and higher 
death-rate, which statistical evidence has shown to exist among persons living in 
crowded and unyentilated rooms. The conditions of temperature, moisture, and 
windless atmosphere in such places primarily diminishes the heat loss, and 
secondarily the heat production, i.e., the activity of the occupants, together with 
total volume of air breathed, oxygen taken in and food eaten. The whole 
metabolism of the body is thus run at a lower plane, and the nervous system and 
tone of the body is unstimulated by the monotonous, warm, and motionless air. 
