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SECTIONAL TRANSACTIONS.—F", G. 431 
The subjects made a number of preliminary experiments in order to get themselves 
acclimatised, but acclimatisation effects can never be entirely avoided. For instance, 
when four consecutive experiments were made in dry air at 100° (d.b.) and 80° 
(w.b.), the mean pulse rate of the subject doing mechanical work fell gradually from 
121-2 to 117-2, whilst the loss of sweat increased from 16-8 oz. to 20-2 oz. per hour, 
The next three experiments were made in moist air at 81° (d.b.) and 80° (w.b.), and 
the sweat amounted to 17-7, 12-7 and 10-8 oz. respectively (i.e. it fell gradually as 
the effect of the preceding dry air experiments wore off). 
AFTERNOON. 
Discussion on Some Contributions of the Biological Sciences. to Economy 
and Safety in Transport. (Chairman: Mr. Hersert 8. Morrison, 
M.P.) :-— 
Demonstration of Psycho-physiological Tests for Selection of Pilots, 
by Squadron-Leader H. L. Burton, arranged by Director of Medical 
Services, Royal Air Force. 
The aim of the tests employed by the Royal Air Force in the selection of candidates 
for flying duties is the differentiation not only of those who are free from any physical 
defect, but, further, of those who will be capable of continuing to function at a high 
pitch of efficiency under conditions of exceptional physical and nervous stress. 
Amongst the attributes a Service pilot must possess is the capability of flying in 
time of war, in any climate, at high speeds and altitudes for prolonged periods. 
The tests, therefore, are largely concerned with the investigation of the circulatory 
and respiratory systems and of the general stability of nervous control, since upon 
these particularly fall the stresses involved in Service flying. 
Records of the original, and periodic similar examinations subsequently carried 
out, afford a valuable means of determining any deterioration in efficiency. The 
index of each individual’s efficiency can be expressed as a simple figure calculated 
from a table in use. 
The methods of examination were outlined and certain of the tests demonstrated. 
M. J. M. Lauy.—Influence de la sélection dans les transports sur 
Vamelioration de Vapprentissage et la diminution des accidents. 
SECTION G.—ENGINEERING. 
Thursday, September 24. 
Sir Ropert Haprietp, Bart., F.R.S.—Notes on a Research on Faraday’s 
* Steels and Alloys.’ 
For the first time, the ‘ Steel and Alloys’ made by Michael Faraday during the 
period 1819-1824 have now been subjected by the author of this paper to complete 
examination including chemical analysis, metallographic, physical, mechanical and 
other tests. Hitherto, the only information available concerning Faraday’s metallur- 
ical researches has been that contained in papers which he presented jointly with 
ames Stodart, F.R.S., to the Royal Institution in 1820 and the Royal Society in 
1822. Not much definite information from the modern point of view is to be gleaned 
from those papers, as they contain very little in the way of chemical analyses or 
quantitative tests. 
By kind permission of the Managers of the Royal Institution, the author has been 
able to investigate the nature and properties of seventy-nine specimens of Faraday’s 
steel and alloys by the aid of the resources of a modern research laboratory. From 
the information thus obtained, which could have been secured by no other means, 
