408 
PROF. LOUIS YESSOT KING ON THE CONVECTION OF 
(v.) The properties of the Kelvin bridge connections make it possible to connect 
an anemometer through low resistance slip-rings and provide a means of attacking 
such problems as the analysis of velocities in the neighbourhood of rapidly revolving 
areoplane propeller blades, or between the blades of centrifugal fans. 
In addition to the applications already mentioned incidentally, it will be noticed 
that the use of the linear anemometer makes it easily possible to analyse the 
distribution of air-velocities in the neighbourhood of obstacles of various dimensions 
and shapes. An important application of this method is to be found in aerotechnical 
problems, such as the analysis of propeller wakes, distribution of velocities over planes 
of various dimensions and camber, &c. A compilation of such data would prove to be 
of the greatest service in developing a rational theory of turbulent flow. An 
instrument of the type under consideration could easily be constructed to give a 
continuous graphical record, thereby greatly extending its usefulness in analyses of 
complicated velocity distributions. 
The application of the theoretical part of the present paper to the measurement of 
the thermal conductivity of gases has already been mentioned ; in the case of liquids 
the chief application of the method lies in the investigation of a possible instrument 
for the convenient and rapid measurement of thermal conductivity. Experiments by 
Rogovskij( 51 ) seem to indicate the existence of a law of heat-loss of the form already 
studied. 
In a somewhat different field of application, the laws of lieat-loss already studied 
probably determine the temperature which a small solid object is able to acquire in 
a current of highly heated gas such as a Bunsen or blow-pipe flame. In fact the 
hot-wire method seems capable of affording a convenient means of analysing the 
velocities and true temperatures of flames or of heated gases in boiler-flues, &c. 
It is hoped at a latter date to undertake in detail the study of some of the problems 
suggested in the present section. 
Before closing the writer wishes to express his sincere thanks to Prof. H. T. Barnes, 
F.B-.S , Director of the Macdonald Physics Laboratory, for the kind way in which he 
has facilitated the present work by every means in his power. 
( 51 ) Rogovski.t, E. A., ‘Comptes Rendus Acad. Sci., Paris, 5 vol. 136, pp. 1391-1393, 1903 ; also vol. 141, 
pp. 622-624, 1905. 
