SECTIONAL TRANSACTIONS.—A, G. 287 
The equation for the temperature distribution in a perfect fluid flowing 
‘ V dé : @6 
past a heated body is Vug?0 = > “de The usual assumption that dp 
26 
is negligible as compared with doa implies an indefinite rate of heat flow at 
the upstream generator of the cylinder. A solution which does not involve 
this assumption is obtained by a method of successive approximations based 
on an application of Taylor’s Theorem. Constant temperature lines are 
drawn in the «, 6 field. 
Measurements of temperature of the air by means of a platinum resistance 
wire stretched parallel to a generator of a metal cylinder (heated internally 
by steam) and placed at different distances from its surface, show the 
characteristic spreading of the isotherms towards the sides of the stream 
beyond an angle of 90° from the upstream generator. 
Careful experiments in which the average rate of heat transmission from 
the surface is measured yield values higher than those obtained by most 
other observers, but closely agree with the recent results of Griffiths and 
Awbery. 
Mr. A. H. Doucias.—Modern building materials with a view to thermal 
insulation of buildings. 
During the last quarter-century, economic pressure, coupled with the 
increasing use of steel and reinforced concrete frameworks, has led to the 
cutting down of thicknesses of traditional building materials, such as brick, 
stone, slate and timber, in the building of walls, floors and roofs, resulting 
in an undesirable lowering of their overall heat and sound insulating qualities. 
Considerations of cost preclude any return to traditional methods, so 
that a solution must be found, (a) by new methods of design, such as 
various forms of cavity wall, based on more accurate knowledge of thermal 
phenomena ; (4) by the introduction of highly insulating non-structural 
materials for use in conjunction with the traditional structural elements ; 
(c) by the development of new forms of structural unit of substantially 
greater insulation value than the existing range, for use either alone or in 
conjunction with the latter. ‘The above methods may of course be used 
either alone or in suitable combination. 
Much valuable work has been done during the past decade in regard to 
(6), for special uses such as refrigeration chambers, but cost has hitherto 
prevented its application to the wider field of general building practice. 
Increasing attention has been paid lately to (c) in an effort to avoid extra 
cost by a wider combination of functions in the material used. Such 
materials, in association with suitable kinds of tensile reinforcement, are 
found to approximate in many ways to the traditional timber element, 
without sharing its disadvantages in regard to fire, movement and rot. In 
fact they might aptly be described as forms of ‘ mineral timber,’ and inter- 
esting results have already been secured by following out this line of thought. 
Mr. A. Linpsay Forster.—Glass silk as an insulator for heat and sound. 
Mr. F. C. Jonansen.—Problems of refrigerated railway transport. 
The relatively short duration of the journeys affects in several ways the 
economics of refrigerated railway transport in Great Britain. For example, 
the cold absorbed by the vehicle on loading and lost on discharging are 
an important proportion of the total refrigeration, and hence low thermal 
