220 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
EIGHTEENTH ORDINARY MEETING. 
The Eighteenth Ordinary Meeting of the Session 1883-84 
was held on Saturday, March 15th, the Third Vice-President 
Dr. George Kennedy in the chair. 
The minutes of the last meeting were read and confirmed. 
The following gentlemen were elected members of the 
Institute : 
T. C. L Armstrong, M, A., LL.B., Henry William Eddis, Esq., and 
Frank Arnoldi, Esq., Barrister. 
The following list of donations and exchanges was read :— 
1. Science, Vol. 3, No. 57, March 7, 1884. 
2. The Canadian Record of Natural History and Geology, Vol. 1, No. 1, 
Montreal, 1884. 
3. Transactions of the Ottawa Field Naturalists’ Club, No. 4. 
4, Annual Report of the Library Commissioners and Libarian of the Legis- 
lative Library of Nova Scotia, and the Librarian of the Nova Scotia 
Historical Society for the year 1883. 
5. Transactions of the Royal Geological Society of Cornwall, Vol. 10, Part 6. 
6. Annuaire de 18S4, de la Société des Ingénieurs Civils, 37¢e. Année. 
7. Appleton’s Literary Bulletin, March, 1884. 
PurRcHASE.—38 Nos. of the Journal of the Franklin Institute of various 
years, to complete a set. 
Mr. T. P. Hall, B. A., Fellow of University College, read a 
paper on “ Photography and the Chemical Action of Light,” 
illustrated by diagrams and apparatus. 
After reviewing the history of photography, Mr. Hall showed 
the scientific value of this art, in leading to a more complete know- 
ledge of the nature of radiant energy. The action of different parts 
of the spectrum upon various substances was explained in connec- 
tion with wave-lengths and atomic vibrations, and the direction of 
future advances in photography indicated. The relation between 
transparency to certain rays and chemical composition, fluorescence, 
phosphorescence, colour-blindness, and other interesting subjects in 
‘this connection were discussed and illustrated. The following is an 
extract: ‘To make photographs which shall appear accurate to us 
we require a compound sensitive to the same rays and in the same 
relative degree as our eyesare. . . . Since, besides being deaf 
to an unknown variety of sounds, we are blind to nine-tenths of the 
light of the spectrum, it becomes a question of interest whether the 
