286 SECTIONAL TRANSACTIONS.—A, G. 
This paper describes methods for the industrial production of ultra- 
violet radiation and some typical applications, and discusses also methods 
of rating such sources to enable the user to evaluate their worth for any 
particular purpose. 
Mr. L. J. Davies and Mr. R. Maxtep.—Some aspects of modern road 
illumination. 
This paper deals with the application of light for the provision, on high- 
ways at night time, of a visibility sufficient for the requirements of modern 
traffic conditions. 
The optics connected with the process of seeing and distinguishing 
objects on artificially illuminated roadways are discussed. Light can be 
applied from moving vehicles or from stationary lighting points, and, for 
economical and other reasons, a mixture of the two methods, adjusted 
according to the traffic burden of the road, is a reasonable solution. 
Some possible lines of development are suggested. 
Monday, September 10. 
(Sir James HENDERSON in the chair.) 
Dr. Ezer GrirFitTHs, F.R.S.—Research on heat transmission and its relation 
to industry. 
In the design of structures involving the conservation of heat or cold, 
data as to thermal conductivity play an important part, and this is illustrated 
by consideration of typical cases which include buildings, furnaces and 
ships. 
Measurements have been made on a variety of heat-insulating materials, 
and data are given for pumice concrete, aerated concrete, aluminium-faced 
asbestos paper, compressed fibre boards, etc. 
In the second part of the paper consideration is given to the question of 
the basic laws of the transfer of heat between gases and solids, and to the 
application of the data obtained to the design of batteries for the heating 
or cooling of air. 
When heated pipes are arranged in bank formation the second layer 
loses in an air stream more heat than the first, whether in square or 
in diagonal formation. In square formation the third layer loses the same 
as the second, whilst in diagonal formation there is an increased loss in 
the third layer over the second. After the third the coefficient is constant. 
The effect of fins fitted to the pipe in increasing the heat transfer is 
considered and data given. 
Dr. J. SmaLL.—Thermal conditions round a hot circular cylinder in a stream 
of fluid. 
An experimental study of the variation in the rate of heat transmission 
from point to point round the surface of a heated cylinder in an air stream 
is made by means of an indicator built into the surface. When the cylinder 
is heated only in the region of the indicator a minimum value is recorded 
at the upstream generator as well as at generators which are about 90° of 
angle from the front. This minimum at the front is not obtained in ex- 
periments on a uniformly heated cylinder. The results are analysed and 
compared with those of other experimenters. 
