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particular room. The first two readings of carbonic acid were 14 and 17 respectively; this fell and
was maintained about 11 as on previous occasions. Temperature varied from 65 to 67, moisture 70.6 per
cent. to 72.4 per cent. Under these favourable conditions, there was greatly improved work ; the quantity
improved 26 per cent. the proportion of errors decreased 30.1 per cent. The mean error of angle drawn
(45 deg.) fell from 7.62 deg. to 6.60 deg., a decrease of 13.4 per cent. The effect of improved ventilation
more than counterbalancing the expected fatigue. On the last day of experimenting, there was fog
and gaslight; the inlets were stopped, so that the air was allowed to deteriorate. The temperature
fell from 72 deg. F. to 66 deg. F ; moisture rose from 71.8 to 100 per cent., and carbonic acid from 24
to 50 parts. Little inconvenience was felt in spite of these high figures being recorded, the teacher
noticing for the first time at the close of the lesson that " something seemed wrong with the ventilation."
The work done was anomalous, the output was 5.2 per cent. less, instead of the increase always noted
before, but the quality was good, only 1.1 per cent increase in errors.
before, but the quality was good, only 1.1 per cent increase in errors. With the angle test (31 deg. and
35 deg. set) there was, however, a great falling off, the mean error of estimation increasing from 5.40 deg.
to 8'81 deg., an increase of 63.1 per cent.
First
Experiment.
June 26, 1906.
Second
Experiment.
July 3, 1906
Third
Experiment.
July 19. 1906.
Fourth
ExperimentFeb
21, 1907.
Fifth
Experiments
Feb. 28, 1907;
I.
Test.
II.
Test.
I.
Test.
II
Test.
I.
Test
II:
Test.
I.
Test.
II.
Test
I.
Test.
II;
Test.
Number of boys present
48 + 1
47 + 2
50
50
49
49
58
58
58
58
CO2 vols. per 10,000
8.5
10.5
9.0
22.5
17.0
11.0
24.0
49.5
Difference T°wet and dry bulb
5.5°
5.0°
5.5°
7.0°
6.0°
6.5°
6.0°
0.0°
Average number of figures worked
10. 6
13.4
13.0
15.0
15.98
16.35
11.16
14.05
14.93
14.16
,, mistakes
0.86
1.84
1.18
2.86
1.48
1.31
1.29
1.24
Mistakes per cent, of figures
8.6
14.3
6.6
12.3
7 .41
17.48
13.3
9.3
8.7
8.8
Percentage change in figuresworked
+ 26.4
+ 15.6
+2.3
+
26.0
-
5.2
„ mistakes
+ 66.3
+ 86.4
+
135.9
-
30.1
+
1.1
Angle set for copy
67°
22°
45°
45°
31°
35°
Angles greater than copy
15
25
12
40
25
39
11
„ less „
34
19
33
14
30
18
44
„ correct
1
5
4
4
3
1
3
Average error in excess
5.0
6.56
6.08
9.45
8.00
6.6
5.6
„ deficiency
6.85
6.37
6.91
4.57
6.10
3.0
10 2
Total excess or deficiency
— 157
+ 43
—155
+ 314
+ 17
+ 205 -
387
Mean angle resulting
56.86°
67.9°
18.8°
39.6°
45.3°
34.5°
28.3°
Mean error
5.92
5.82
6.14
7.62
6.60
5.40
8.81
Percentage (+) or (—) of mean error
-
+ 5.5
13.4
+
63.1
These few observations tend to confirm the results of other observers, such as Burgerstein*, as
to the effect of slight fatigue on improving the capacity for mental work. They strongly suggest that in
any future observations on fatigue made on children in crowded rooms, the conditions of ventilation may
constitute an all-important factor in the results.
A curious point probably involving a psychological explanation dependent on ocular movements
is that on each day there was a tendency to over-estimate the angle at the first test, and to underestimate
it later. This reversal was complete on the days when bad ventilation was accompanied by deteriorated
work, but with the good ventilation, although there was still overestimation at first, the number of under
c6timations only just exceeded the over-estimations in the second test. Unfortunately, other work
prevented this exceedingly important question of fatigue being followed up.
A further extended series of observations on the effects of varying the atmospheric conditions
on the school work has been made by Dr. Hogarth and Dr. Brincker.
General Methods Of observation. The school work was allowed to take its ordinary
course, the atmospheric conditions and variations being carefully noted, and after a time artificially
altered in certain ways.
The subjective and objective signs observable in children, teacher, and doctors were also noted,
and, as in the enquiry just detailed, an attempt was also made to ascertain the veriations in the working
capacity of the children.
The Method of Recording Variations in the Capacity of the Children.
After a considerable number of preliminary observations, subjective tests were rejected as of little value.
Then algebraic and arithmetical problems were tried, and also memory tests, but finally simple arithmetical
tests were adopted as most suitable for comparisons. A set of twenty multiplication sums of three
figures was given, the figures being placed side by side in columnar form, to be done in five minutesThen
an estimate was obtained of the number of sums done right, number wrong, and number omitted.
The work was given out (Test I.) at the commencement of the school session, and the results collected
in five minutes. A like process (Test II.) was repeated two and three quarter hours later. The Head
* Burgerstein, Dr Leo, "The Working Curve of an Hour," Trans. VII:, Congress of Hygiene and
Demography. London, IV., 87
14958 H 2
59