PROCEEDINGS 
OF THE 
EOYAL SOCIETY OF EDINBUEGH. 
VOL. V. 1864-65. No. 67. 
Monday, February 1865. 
Sir DAVID BEEWSTER, President, in the Chair. 
The following Communications were read : — 
1. Experimental Inquiry into the Laws of Conduction of 
Heat in Bars. Part II. — On the Conductivity of Wrought 
Iron, deduced from the Experiments of 1851. By Prin- 
cipal Forbes. 
This is a sequel to a paper read 28th April 1862 (See Proceed- 
ings,” vol. iv. p. 607), and contains the results of the complete 
reduction of the observations on the conductivity of iron, by the 
application of tho method there described. The thermometric 
readings are now rigorously corrected for scale errors, and for the 
difference of temperature between the bulb and the stem. 
The methods of reduction, consisting of a combination of calcu- 
lation and graphical projection, are the same as have been described 
in the first part of the paper. / But the whole has beeen executed 
with minute attention to accuracy, and the avoidance of error of 
every kind. 
Three cases are distinguished in the experiments and reductions, 
each complete in itself. 
In Case I. a wrought-iron bar, fully 8 feet long and IJ inch 
square, heated at one end, had its temperature observed at different 
points. The surface was moderately polished. 
3 c 
VOL. V. 
