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NATURE 
yD) 
=<; 
[APRIL 1915 
nursery often checks the physical development of | sinuses, resulting in obstruction of the nasal air- 
the young, and leads to a lessening of national 
vigour and health. The open-air school works 
wonders on the badly nourished, defective chil- 
dren, and should become the school of every child 
in the community. The camps of to-day placed 
in the wind-swept open spaces of the land are 
founded on the emergency of war, but should 
become the week-end playgrounds of the nation 
in times of peace. Our cities have been built so 
as to satisfy regulations based on the chemical 
theories of ventilation and the nursery-bred fear 
of cold. They should be re-planned so as to allow 
the maximum of sunlight and wind, affording 
baths and exercise grounds for all. The con- 
ditions of life at present wage a deadly war against 
us. We listen for the whirr of the Zeppelins, and 
take little heed of the silent sowing of the germs 
of preventible disease. 
< Om STeRCnUMGNemEnese 

healthier conditions we 
ra] _ require instruments 
i | which will measure the 
ie ' physical conditions of the 
1H atmosphere and make 
manifestthedifferences be- 
tween confined and open 
air. The thermometer re- 
gisters the average tem- 
perature of the surround- 
ings; it gives us no in- 
formation as to the rate 
of heat loss from the sur- 
face of the human body. 
It is the rate of heat loss 
which matters to us. 
Out of doors, on ideal 
spring days, the ground 
is warm and the wind 
scarcely moves at foot- 
level, while our heads are 
blown upon by a variable 
cooling breeze; the sun 
warms one side of us 
while the other is cool. 
The clouds chasing each 
other across the blue 
sky give us shade alternating with sun. Our 
feet are kept warm, our heads cooled, and our 
cutaneous nerves are continually excited by the 
ever-varying rate of cooling. There is no 
monotony, but an agreeable energising of our 
nervous system. When the heating and venti- 
lating engineer gives us a uniform summer tem- 
perature of 63° F. by means of steam coil (so 
called) radiators, he secures us a warm atmo- 
sphere above and a cold floor below, cold feet and 
warm heads, and a deadly monotony of conditions. 
The right system of heating and ventilation would 
give us a warm floor and a variable, gentle, cool 
breeze moving round our heads. 
In the House of Commons the engineer forces 
air, heated to 63° F:, through a perforated floor, 
and thus, cooling the Members’ feet, gives 
them conditions which ‘lead’ to congestion’ of 
the mucous membrane of the nose and its air- 
NO. VOL. 95 | 


Fic. 1.—The Wet and Dry 
Katathermometer. The Dry 
instrument is shown enclosed 
in a wire cage, which was 
used for taking observations 
in investigations on clotbing. 
9252 
“I/9) 

way, feelings of stuffiness in the head, and 
increased liability to infection by the germs of 
“colds” and influenza. A system more contrary 
to the outdoor ideal conditions could not have been 
invented. To measure the physical conditions 
outdoors and indoors we require an instrument 
which will measure the rate of cooling by radia- 
tion, convection, and evaporation, and will tell 
us whether the atmosphere is monotonous or 
not. The present writer has introduced the 
katathermometer for making these measurements, 
and with Mr. O. W. Griffith has introduced an 
electrical instrument, the caleometer, for the 
purpose of recording not only rate of cooling, but 
indicating whether the atmosphere is monotonous 
or lively. 
The katathermometer (Fig. 1) is a large-bulbed 
spirit thermometer, made (by Mr. J. Hicks, 8 Hat- 
ton Garden) as nearly as possible of a standard 
size. Each instrument is tested against a standard 
one, and a constant obtained by which the rate 
of heat loss can be deduced in calories per sq. ; 
cm. of surface. The katathermometer is heated 
in warm water until the spirit just rises into 
the top bulb, and the column is free from 
bubbles. The instrument is then wiped dry and 
suspended in the atmosphere, and the time 
observed taken by the meniscus in falling from 
100° F. to 95° F. This gives the rate of heat 
loss by convection and radiation, the instrument 
being approximately at body temperature. A 
muslin finger-stall is then drawn over the bulb 
and the operation repeated after heating the in- 
strument and jerking the excess of water off the 
muslin cover. ~The time taken in this case gives 
us the heat loss by radiation, convection, and 
evaporation. The difference between the dry and 
wet readings gives us the heat loss by evaporation 
only, and. from. this, when the readings are 
taken in still air, the vapour pressure can be 
determined. 
The value of rate of heat-loss measurements 
are seen by the following examples :—(1) Inside 
a cottage room on the East Coast and outside 
on the ‘cliff -edge thé summer - temperature 
was the same, but outside the katathermometer 
cooled much -faster. It registers just as the 
human body feels the bracing effect of the moving 
air. It acts as. an’ anemometer, sensitive not 
only to currents in. one direction, ‘but to every 
eddy which’ the ordinary ‘anemometer fails to 
register. The instrument shows the vast difference 
between the conditions of the indoor and outdoor 
worker. (2) Inthe’ debating: chamber of the House 
of Commons the thermometer régisters a tempera- 
ture of 63° at foot and head level, but the katather- 
mometer shows the rate of cooling is 50 to 100 
per cent. greater at foot level than at head level. 
When the conditions were experimentally altered 
in ‘one part of the House so that all floor inlets 
were closed, and the air introduced at the gallery 
level, the rate of cooling became slower at foot 
level than at head level. Then the congestion of 
the nose was relieved as the feet became warm 
and comfort was secured. (3) In a room heated 
