of Edinburgh, Session 1^‘^'2-^Z. 47 
The following Communications were read : — 
1- The Diurnal Variation of the Force of the Wind on the 
Open Sea and near Land. By Alexander Buchan, M.A. 
2. On the Semitic and Greek Article. By the Eev. Dr Teape. 
0. On the Nature of Solution. By W. W. Nicol, M.A., B.Sc. 
4. On the Kelative Electro-Chemical Positions of Wrought 
Iron, Steels, Cast Metal, &c., in Sea W^ater and other 
Solutions. By Thomas Andrews, Assoc. M. Inst. C.E., 
E.C.S. Communicated by Professor Crum Brown. 
BUSINESS. 
The following candidate was balloted for, and declared duly 
elected a Fellow of the Society : — Dr E. Peel Eitchie. 
Monday, 2^th January 1883. 
THOMAS STEVENSON, Esq., M. Inst. C.E., Vice- 
President, in the Chair. 
1. Observations of the Eainband from June 1882 to January 
1883. By Hugh Eobert Mill, B.Sc., F.C.S. Communicated 
by Professor Tait. (Plate I.). 
The series of observations to be described was undertaken in order 
to ascertain how far a small pocket spectroscope could be relied upon 
for the prediction of rain, with a view to its popular use for that 
purpose. 
The instrument employed was Hilger’s smallest sized direct- vision 
spectroscope, its length being one inch and a half, and its diameter 
half an inch. It was furnished with the ordinary adjustable slit, and 
had no special provision for the exclusion of dust. It is desirable, 
however, to use an instrument which has the eyehole protected by a 
plate of thin glass, and the slit covered with a thicker plate. In 
this case care must be taken to keep the glass free from scratches, 
which greatly obscure the spectrum. 
When the spectroscope is to be used the slit is made as narrow as 
