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extent than with erect burners. They are also very susceptible to variations in pressure, and at times
give very poor light. They easily get out of order and require a great deal of attention. In some nonprovided
schools they are found in very bad condition.
Refraction and reflection in certain forms of shades have been much recommended in America
for school use. The " Prismatic " and "Kalophane " globes were examined. The " Prismatic " globe
has the outer surface of a glass bowl moulded into a series of prisms, running round the bowl and so placed
as to throw light downwards. It is very effective, especially when a flattened opal shade closes the
mouth of the bowl. The combination is costly and heavy, and an equally good effect can be obtained
with the 90 deg. shade globe.
Indirect illumination by reflection is now a very favourite method in the newer German schools.
By this method, powerful lights, usually arc lamps, are hung from the ceiling with metal reflectors below
them, the light is thrown on to the white ceiling or to special reflectors and reflected as a delightfully
uniform and soft radiance over the whole room. The effect is not unlike daylight of modified brilliance,
and it is most successfully employed in shops and showrooms, where the deep shadows of direct light
would be destructive of the general effects of mass and colour required to be shewn. It is
however, not good where continuous and detailed work at a desk is required. The system was adopted
in the New Anatomical Laboratories of Cambridge University. but has had to be superseded by direct
glow lamp illumination.
With the increase of evening continuation schools, the lighting of the gateways and entrances of
the schools becomes a matter of importance. At present the precincts of a school at night are generally
the darkest part of a street, and the dark exterior is scarcely a fair indication of the light that shines
within.
VENTILATION.
Since reporting in 1904 on experiments on the need for ventilation of certain classrooms,
chiefly shewn by determinations of the deterioration of air by the carbonic acid gas present, attention
has been directed to the almost inexplicable subjective feelings of languor and fatigue noticed
in many mechanically as well as naturally ventilated schools. Some mechanically ventilated schools
are almost museums of mistakes, most in London are failures from want of appreciation of the problems
to be treated, but the failures are purely in matters of engineering. It only seems to be in schools with
warmed air, where the air supply runs up to about 2,000 cubic feet per head per hour, that freedom
from the easily induced exhaustion is found. Although every school room should be mechanically
ventilated, yet the necessary arrangements with low pressure fans, otherwise desirable for school purposes,
seem in London to be almost out of the question owing to cost in space and material.
From Haldane's observations, the actual amount of respiratory carbon dioxide appears to
have little to do with the production of unpleasant symptoms, and no evidence can be obtained of the
existence of the anthropotoxin previously generally supposed to exist. He favours the idea that temperature
and humidity, by interfering with the loss of heat from the body surface, disturb metabolism and
induce unpleasant or even dangerous symptoms. These observations have been independently confirmed
by various workers in the laboratories of Professor Fliigge at Breslau.
It has therefore been attempted to supplement the previous observations on school air in London
by observations on Fatigue and also on the relation of the atmosphere to the working capacity of the
children.
The Effect of Ventilation on School Fatigue. Dr. Thomas and Dr. Stevenson
made a few observations during the year at St. George's Row School, Pimlico, a school ventilated on the
plenum system, warmed and moistened air being driven in from the basement by a low pressure fan
through large ducts to the classrooms. There was practically no interference with the school work.
The tests used to determine the efiects of fatigue on the boys during the school session were the numbers
of simple addition and subtraction sums of simple integers which the boys could do in five minutes at the
beginning and end of their tasks. It was also attempted to use the estimation of an angle which was
copied by eye from the blackboard, to assess the correct judgment of the boys. On the first two occasions
the ventilation proceeded naturally. The carbonic acid gas present and the humidity were determined
at regular intervals. The moisture was practically constant under normal ventilation both in July
and February, only varying between 71.4 per cent. and 73 per cent. On these two occasions
the temperature varied from 60 deg. F. to 72 deg. F., and the carbonic acid present from 6 to 12 per 10,000
volumes.
The effect of teaching under these normal summer conditions was shewn by an increase in the
quantity, but greater decrease in the quality of the work done in the time. The number of figures worked
at the second test being 24'6 per cent. and 15.6 per cent. respectively in excess of the first, but the proportion
of errors to figures being increased 63.3 per cent. and 86.4 per cent.
On the third occasion, by blocking the inlet ducts, the ventilation was converted into an ordinary
naturally ventilated system, with inadequate inlets, air entering by the upper valves of the outlet openings
and leaving by the lower. The humidity during the session rose to 81.4 per cent. and the carbonic acid
from 10 0 to 22'5 ; the temperature rising from 71'5 deg. F. to 74.5 deg. F.
The increase in amount of work done on the previous days now fell to the insignificant amount of
2.3 per cent. whilst errors were increased by 135.9 per cent. The angle test, in which the boys were
set to copy as accurately as they could angles of 67 deg. at the first test, and 22 deg. at the second, shewed
a mean error of 5'82 deg. at the first and 6'14 deg. at the second test.
On the fourth occasion the ventilation on entering the room was found hindered, and a stuffy smell
existed, the caretaker's attention being drawn to this, considerable improvement was effected in this