318 REPORT—1905. 
Association, I can offer you no better wish than that you may produce some 
men of genius and a multitude of able workers who, by their researches in 
our scienees, may add to the fame of your country and contribute to the 
intellectual progress of the world. 
The following Papers were read :— 
1. Observations on Atmospheric Electricity in South Africa. 
By Professor J. C. Beatriz, D.Sc., J. Lyi, M.A., and 
W. H. Loceman, J.A. 
The observations carried out up to now consist of a series made at Bloem- 
fontein in 1902-1903 by Mr. Lyle, of the Grey College, Bloemfontein, and a less 
complete series made during the same period at Cape Town by Mr. W. H. 
Logeman. Observations have also been carried out in Cape Town by Mr. Fincham 
during the present year. ri 
The instruments used were an Elster and Geitel dissipation apparatus, and—less 
regularly—a Kelvin portable electrometer. 
The paper contained the records of daily readings of temperature, humidity, 
ressure, and both positive and negative leaks for morning and afternoon hours. 
hese results are used to determine the annual variation ; a harmonic analysis of 
the results being obtained in the usual way. 
Cape Town is on the coast practically at sea-level. 
Bloemfontein is inland, and about 4,500 feet above sea-level. 
The magnitude of the leak is greater at Bloemfontein than at Cape Town. 
The positive ieak, both at Cape Town and at Bloemfontein, is less than the 
negative in the morning; the positive leak in the afternoon in Bloemfontein is 
greater than the negative in the summer months, less in the winter months. In 
Cape Town, so faras the observations go, it seems probable that the opposite is 
true, that is, from June to October the positive leak is greater than the negative, 
and in November and December less. 
Mr. Lyle and Mr. Fincham had in addition observed on several days throughout 
the whole day. The chief results are similar to those obtained in Europe. 
Formation of fog leads tu a diminution in leak, The rate of leak changes with 
the relative humidity and with the pressure. * 
2. Apioidal Binary Star-Systems. By ALEXANDER W. Ropserts, D.Sc., 
F.R.A.S.—See Reports, p. 249. . . 
3. On the Convergence of a Reversed Power Series. 
By Professor A. Brown, JA. 
For some purposes it is useful to have a knowledge of definite limits within 
which a reversed series converges. The following investigation supplies such a 
knowledge, though the limits obtained are generally rather narrow. 
Start from 
TE RAs eel Mae : : : 0 q) 
which is the series to be reversed, the ’s being real. 
— UL _ 1 b 2 
a A i,t Ligeti ol : : , : (2) 
If we apply the method of suecessive approximations we have, first, 
WY 
re. 
1 
