AND STATICS UNDER THE INFLUENCE OF LIGHT. 
345 
and evacuated to a high vacuum of about O'Ol millim. Taps (16), (17) and (21) were 
then closed, and chlorine prepared in (7) till the pressure in the reaction vessel 
became equal to about 10 centims. Tap (6) was connected with the removable 
pump (M), and (M) and (R) heated and evacuated, carbon monoxide sent into it 
from (15), again evacuated, and then (17) and (21) opened and the chlorine removed. 
The taps (17) and (16) were then turned off, (6) connected with the pumps, 
(R) evacuated, all vessels (13), (14), (15), (R), (S), (E') and (18) evacuated, and 
carbon monoxide from (9) and (10) removed as far as possible, partly by opening 
tap (11) and then removing the same from (15), &c., partly by allowing the freshly- 
prepared carbon monoxide to bubble for some time in (12). The bulbs (15), (S) and 
(18) were then finally repeatedly filled, at one atmosphere pressure or more, with 
fresh carbon monoxide from (10) (prepared in the dark, only one incandescent lamp 
at a distance being used). The quantity and pressure of the carbon monoxide 
introduced into the glass bulb (18) is known from the volume of the bulb and from 
the indications of the manometer connected with it. The tap (17) was then turned 
off; the reaction vessel was next completely protected from light. The tap (28) 
was now turned on, and 1 or 2 centims. of the tube containing cupric chloride was 
then slowly and cautiously heated (in the dark), so as to evolve chlorine and to allow 
it to pass to the reaction vessel at a slow rate. From the indications of the 
manometer the amount of chlorine introduced into the quartz vessel was known, and 
the production of chlorine was stopped by removing the burner from the tube as 
soon as the desired quantity of chlorine, which is very small, had been introduced 
into the quartz vessel. The capillary tube was immediately sealed up with a hand 
blow-pipe at i / —where it had been previously drawn out. After the heated parts 
had cooled down, the position of the meniscus of the mercury and of the concentrated 
sulphuric acid was read in both arms of the manometer by means of a faint light, 
as well as the temperature of the room and the barometric pressure. The manometer 
(E') was again read, the tap (22) closed, the tap (21) opened, and the carbon 
monoxide, which is at a greater pressure in (18) than the chlorine in the reaction 
vessel, was slowly allowed to pass through the drawn-out capillary tube (at i„) to 
the quartz vessel, so as to keep the SOjHo column over the mercury the whole time 
long enough, and when the mercury no longer moved in the manometer (E), the 
tap (21) was closed and the capillary tube sealed at i u —where it was previously 
drawn out. The vessel was again allowed to cool and the temperature and pressure 
readings again noted. 
From the variation in the height of the manometer the quantity of carbon 
monoxide introduced into the quartz vessel was known. The volume of the bulb (18) 
is immaterial, if it is of sufficiently large size to allow o,f the introduction of any 
desired quantity of carbon monoxide into the reaction vessel. The bulb (18) was 
then taken off, the end with the tap (21) immersed in a beaker containing a solution 
of potassium iodide, and the tap opened. It was found that with the above 
YOL. CXCIX.-A. 2 Y 
