TRANSACTIONS OF THE SECTIONS. A7 
3rd. As the barometer becomes lower, the amount of ozone becomes greater. 
Ist. If the temperature be ranged in 10° series, a temperature between 30° and 
40° will give less ozone than one between 40° and 50°, and this less than one 
between 50° and 60°. Artificially, if a night-light be made to bum in a 
cell below the box so as to warm it, there will be an increase in the 
amount of ozone over another box that is without a night-licht. 
2nd. With respect to an increase in ozone resulting from an increase in the 
speed of the air, it is shown from this series of observations that the most 
ozone has been present when there has been a gale blowing. It does not 
necessarily prove that under these circumstances there is actually more ozone 
in the air; for it must be borne in mind that if the amount of ozone in a 
cubic foot of air were always the same, still if today 300 cubic feet of air 
only occupies the same space of time in passing through the box as 100 cubic 
feet occupied yesterday, we shall have more ozone apparently shown today 
than yesterday. Then again, as chemical action increases with an increase 
of heat, it is also manifest that the same amount of ozone passing through 
the box at a temperature of 60° would necessarily darken the paper more 
than the same amount at a temperature of 40°. 
It is quite clear that certain corrections are requisite in order to find the 
actual amount of ozone. 
3rd. With regard to the pressure of the air, there is a striking difference be- 
tween the readings of the ozonometer with a high or low barometer. Taking 
the four days in each month during the past year on which the mean 
pressure was greatest, the average amount of ozone was 1-2, whilst on taking 
the same number of days when the barometer was lowest, the mean was 
4-1, or nearly four times as much ; four years’ observations give very similar 
results. The mean maximum pressure for the whole twelve months of the 
four years is 30°22 inches, the mean ozone being 1:0; the mean minimum 
pressure for the like period is 29-18 inches, the mean ozone heing 3:2, 
With the barometer at 283 inches the mean ozone is 5:7 
” 283 ” ” 4] 
” 29 ” ” 35 
” 294 ” ” 2°8 
” 293 ” 2:0 
” 293 ” ” 16 
” 30 ” ” 13 
” 30} ” ” 0-5 
” 303 ” ” 0-4 
There is a difference between the amount of ozone during the night and day at 
different seasons. 
In December and January an excess at night over the day of 0:8 
0: 
In February and March “ x 
In April and May i + 0:7 
In June and July ip 0-1 
In August and September a fe 0-4 
In October and November “ “ 05 
The average of the summer months being in excess only one-half of that which 
occurs in the winter. 
On the Luminosity of Phosphorus. By Dr. Morrar. 
If a piece of phosphorus be put under a bell-glass and observed from time to time, 
it will be found at times luminous, and at others non-luminous. When it is 
luminous, a stream of vapour rises from it, which sometimes terminates in an in- 
yerted cone of rings similar to those given off by phosphuretted hydrogen ; and at 
others it forms a beautiful curve, with a descending limb equal in length to the 
ascending one. Results deduced from daily observations of the phosphorus in con- 
nexion with the readings of the barometer, the temperature and degree of humidity 
of the air, with directions of the wind, for a period of eighteen months, show that 
periods of luminosity or phosphorus and non-luminosity occur under opposite con- 
