176 ILLINOIS ACADEMY OF SCIENCE 
equations for a bent as a whole as there are unknowns and 
the unknowns can be determined. 
V. CONCLUSIONS 
The number of equations involved in the slope-deflection 
method is so great that the method can not be used 
in designing buildings. The method, however, was used 
by the writer and Mr. Maney to determine the stresses 
in a number of typical bents, after which the stresses were 
also determined in the same bents by the four approximate 
methods described above. As a result of these calculations 
it was found that for bents for which all columns of a story 
have the same section Method I and Method IV are accurate 
enough for the purpose of design. 
HEAT TRANSMISSION OF SIMPLE AND COM- 
POUND WALLS, WITH SPECIAL REFERENCE 
TO BUILDING CONSTRUCTION 
ABSTRACT 
ARTHUR C. WILLARD, UNIVERSITY OF ILLINOIS 
1. Consideration of the theory involved in the transmis- 
sion of heat through a wall, and the relation between radiation, 
convection and conduction as involved in the process. 
2. The effect of air movement on the film of air in Contact 
with the surface of the wall, and the difference between the air 
and surface temperatures. 
3. Determination of coefficients of transmission, based 
on inside and outside air temperatures. 
1. The transmission of heat through a simple or compound 
wall, such as may be used in practice for the exterior walls of 
buildings, is a phenomenon of very general and practical in- 
terest. The calculation of the amount of heat transmitted in 
this way becomes one of the determining factors in propor- 
tioning any sort of heating or refrigerating system, and also 
serves as a ready means of comparing the relative heat insu- 
lating efficiencies of any form of standard wall construction. 
