56 1.8.C. Proceedings of the Ninth [N.S., XVII1. 
No. 2. Improved water model for heat conduction along a shewing 
radiation effect. 
. 3 Comparison of conductivities by ‘* Null Method.”’ 
No. 4. Apparatus for shewing convection of hot air. 
No. 5. Optical compendium. 
No. 6. Mechanical Model for demonstrating Snell’s Law. 
No. 7. Apparatus for shewing apparent contraction of stretched 
India Rubber on heating. 
o.8. Apparatus for shewing adiabatic heating of rubber on 
sudden stretching. 
‘ Apparatus for shewing equality of pressure at a point ina 
iquid. 
No, 10. Commutators (2 Varieties). 
The Pedal line family of a triangle —By A. NaRASINGA 
Rao. 
In th e 
of a triangle are deduced from certain fundamental characteristics of 
a. e 
tric method than the one given in text-books. The problem of de- 
termining all triangles which have a common pedal line system is also 
tov upon. . 
Some recent researches at Kodaikanal.— By J. EveRsHED. 
The Albedo of the Earth.— By C. V. Raman. 
The Molecular Scattering of Light in Gases.—By K. R. 
RAMANATHAN. 
Section of Chemistry. 
President :—Dr. N. R. Duar, F.1.C. 
Presidential Address. 
Inpucep Reactions AND MECHANISM OF CHEMICAL 
CHANGE. 
if 4 and B chemically react with one another while A and 
Definition, 
to the equation :— 
2HgCl, + H,C,0, = 2HgCl + 2HCl + 2CO, 
