ORDINARY MEETINGS. XX1 
Nitschia amphioxys, Ehr. N. elongata, Grun. N. spectabilis, Raljfs. 
N. sigmoidea, Nitesch. Stenopterobia anceps, Breb. Fragillaria con- 
struens, Grun. F. c. var. binodis, Grun. F. capucina, Desm. F. 
undata, W. Sm. Synedra ulna, Ahr. Meridion cireulare, Ag. Tabel- 
laria floculosa, Roth. T. fenestra, Lyngb. Cyclotella operculata, Ag. 
C. comta var. affinis, Grun. Melosira distans, hr. M. arenaria, Moor 
M. orichalcea, Mertens. M granulata, Ehr. M. crenulata var. valida 
Grun. 
A vote of thanks was tendered Dr. Mackay for his address. 
THIRD ORDINARY MEETING. 
Legislative Council Chamber, Halifax, 9th January, 1899. 
The Frrst Vice-Presipent, Dr. MacKay, in the chair. 
Lee Russexi, Ese., B. Sc, of the Normal School, Truro, read a 
paper on ‘‘School-room Air,” as follows : 
One of the great problems of modern mechanics is to increase the 
efficiency of machines, to get the greatest amount of work done with a 
given expenditure of energy. Every possible device is used to lessen 
friction, to minimize waste, and to apply more advantageously the force 
employed. Rails in place of the uneven ground, roliing, instead of 
sliding, friction, are familiar examples of the gains made in the single 
direction of lessening friction, and many more might be instanced. 
These are purely physical instances, but the illustration may be carried 
further. Intellectual processes are as subject to waste and loss. Inter- 
ruption, noise, disease, poisuns, are the causes of loss in mental operations, 
as are dust, friction, inertia, and radiation, in those of a physical nature. 
Such considerations as these first led me to investigate some of the 
causes of decrease of efficiency in school. 
lt appears to me plain, that as the school year advances, there is a 
decrease in mental power in both teachers and pupils. By this is meant, 
that for a given result, more energy must be expended toward the close 
of the year than at the beginning. 
This is not susceptible of exact proof, except by long and carefully 
conducted experiments, but from observations made upon the students 
at the Normal Scbool at Truro I believe such to be the case. 
