19 
not plainly foreshadowed by Davy. An interesting presen- 
tation of some of the most important facts may be found in 
an article by Prof. Le Conte, published about 20 years since 
in the American Journal of Science. 
The tests with standard candles, which are alluded to by 
Mr. Collingwood, were made with all convenient care. Four 
trials were made, four burnings in the caisson and four at my 
laboratory. The apparent discrepancy with the coach candle 
trials is satisfactorily explained, if we consider that the carry- 
ing capacities of the wicks did not vary with the other con- 
ditions of the experiments. 
Pror. Joy read a paper by Dr. O. W. Morris, on the 
meteorology of the month of January, 1873, The month 
exhibited unusual variations of temperature, the total range 
having been 50°; while the mean was 28°5°, a lower average 
than has been recorded for this month during ten years past, 
with the exception of 1865, 1867, and 1868, and 1-:96° lower 
than the total average for the ten years. 
The most rapid change of temperature took place between 
2 P. M. of the 28th, 32°, and 7 A. M. of the 29th, 2°, a fall of 
30° in fifteen hours. The highest mean for any one day was 
44°33°, on the 16th, and the lowest was 7:56°, on the 29th. 
The barometer ranged from 80-467 to 29°487, a difference 
of 1:08 inch. The mean for the month was 29-946. 
The prevailing winds have been north and north-east. 
Snow fell on eight days. The quantity of water from rain 
and melted snow was 6°82 inches, an amount greater than 
that in any January for the past ten years. The mean rela- 
tive humidity has been 67°71, full two-thirds of saturation. 
The air was actually saturated on the mornings of the 8d 
and 16th, and nearly so on those of the 24th and 27th; while 
on only four mornings, the 6th, 12th, 23d, & 31st, has it been 
less than half. 
During the first fifteen days of the month the total number 
of deaths in the city was 1163, giving an average of 775 
‘daily. 190 of these were caused by consumption, and 95 by 
whooping-cough, croup and diphtheria. The number of chil- 
