PiiOrESSOE BIJNSEN AND DE. H. E. EOSCOE’S PHOTO-CHEMICAL EESEAECHES, 881 
The flame of carbonic oxide, upon which all our measurements are founded, issued 
from a chcular platinum burner 7 millimetres in diameter. The normal velocity with 
which the gas issued, was taken to be such that 5 cubic centimetres of gas, at 0° C. and 
0-76 pressure, passed through the burner in 1 second of time. As, however, it was 
practically impossible so to regulate the supply of gas that it should issue exactly at the 
required rate, we were obliged to determine, first of all, the relation existing between 
the supply of gas and the luminosity of the flame. This determination we have made, 
by means of photo-chemical measurement, for velocities of issue lying near the standard 
rate of 5 cubic centimetres per second. The carbonic oxide used for these experiments 
was prepared by the action of sulphuric acid on pure formiate of soda, and after being 
washed with potash, was collected in a large gasometer, previously calibrated, in which 
the volume of gas could at any moment be read off, and the temperature and pressure 
observed by means of a thermometer and manometer. The insolation-vessel of our 
chemical photometer was placed at a distance of 176millims. from the flame. The 
gas contained in the gasometer under a constant pressure of 0“-8 of mercury, passed 
through a very narrow stopcock into the wide tube on which the burner was placed, 
so that when the gas issued from the burner the excess of pressure over that of the 
atmosphere, measured by a small manometer, amounted to a column of water a very 
small fraction of a millimetre in height. 
The actual observations which are thrown together in the annexed Table, were made 
in the following manner. One observer at fixed intervals read off the chemical action 
of the flame as seen on the index of the instrument, whilst another noted the volume of 
gas contained in the gasometer before and after the experiment, as also the temperature 
and pressure. 
Table I. 
II. 
3 
6 
5 
10 
III. 
IV. 
V. 
5342-7 
m 
0-8230 
20-0 C. ] 
4274-2 
0-8244 
20-0 C. / 
3907-3 
0-8254 
20-0 C. 1 
2237-9 
0-8280 
20-0 C. / 
6596-7 
0-8179 
19-5 C.l 
5439-5 
0-8195 
19-5 C.J 
8600-8 
0-8199 
20-0 C. 1 
6762-1 
0-8219 
20-0 C.J 
VI. 
VII. 
9- 
yiii. 
w. 
41-8 
5-950 
13-932 
56-7 
4-673 
9-450 
34-0 
3-839 
6-799 
41-5 
3-053 
4-152 
Column I. gives the number of the experiment ; column II. the duration of the expe- 
riment in minutes ; column III. the volume of gas, in cubic centimetres, contained in the 
gasometer before and after the experiment ; columns lY. and Y. the observed pressure 
and temperature ; column YI. the chemical action effected during the experiment, read 
off on the scale of the instrument ; column YII. the volume (y) of carbonic oxide, reduced 
to 0° and 0'76, which issued in one second; and, lastly, in column YIII. the chemical 
action (w) effected in one minute expressed in divisions of the photometer-scale. 
