358 SECTIONAL TRANSACTIONS.—AT, B. 
Latest photoelectric instrument for measuring the amount of ozone. Hase of 
measurement. Observations possible on clear or cloudy day. Object of instrument 
to enable daily observations to be made regularly. Programme for systematic 
observations over N. Europe. 
Photoelectric instrument having great sensitivity allows observations to be taken 
either in direct sunlight or the light from the clear zenith sky until the sun is nearly 
setting. Method of deducing height and distribution of ozone through the atmosphere 
from such observations. Average height probably about 40 km. distributed between 
the surface and 100 km. but further observations necessary. 
Effect of ozone in raising the temperature of the atmosphere at great heights. 
High temperature causes bending down of sound waves and gives rise to audibility of 
explosions at great distances. Temperatures of upper air calculated from absorption 
of sunlight by ozone and from observations of sound waves agree in general features. 
Prof. 8S. Coapman, F.R.S.—Atmospheric Absorption of Sotar Radiations and 
some Associated Phenomena. 
The absorption of solar radiations in the upper atmosphere of the earth is discussed, 
taking account of the curvature of the level surface. Diagrams are given to illustrate 
the degree of absorption at noon in high latitudes in winter and in other latitudes 
during the hour before the sun has become visible at ground level. The results bear 
on (a) the annual variation of ozone in high latitudes (6) the daily variation of 
ionization and (c) the emission of light by excited atoms in the upper atmosphere. 
Report of Committee on Seismological Investigations (see p. 253). 
SECTION 8.—CHEMISTRY. 
Thursday, September 24. 
PRESIDENTIAL AppRESS by Brig.-Gen. Sir Harotp Harriey, C.B.E., 
F.R.S., on Michael Faraday and the Theory of Electrolytic Conduction 
(see page 31). 
Discussion on The Influence of the Medium on the Properties of Electrolytes. 
(Introduced by Sir Harotp Hart ey.) 
Prof. P. Despye.—The Relationship between Conductivity and Frequency 
in Different Solvents. 
Sir Harotp Hartiey.—EHvidence from Conductivity Data. 
Prof. N. J. Bysrrrum.—The Forces between Ions and Solvent Molecules 
and their Relation to the Solubility of Electrolytes. 
Prof. J. N. BRonstrep.—Some Aspects of the Medium Effect on the Solubility 
of Electrolytes. 
Prof. K. Fasans.—Factors determining the Forces between adjacent Ions 
in Solution. 
Prof. J. C. Putuip, F.R.S.—A Comparative Study of the Nitriles as Solvents. 
Dr. E. A. Guecennemm.—Ionic Equilibria. 
Dr. J. A. V. ButLer.—Behaviour of Electrolytes in Mixed Solvents. 
Prof. G. ScarcHarp, Dr. E. Lance, Prof. J. W. McBarn, F.R.S., Prof. 
T. M. Lowry, F.R.S., Dr. N. V. Sipewick, F. RS. 
