346 
DR. MEYER WILDERMAN ON CHEMICAL DYNAMICS 
arrangements, i. e., with a thin capillary tube drawn out at [if and with an over¬ 
pressure of carbon monoxide in (18), not a trace of iodine {i.e., of chlorine) can be 
detected in the bulb (18), even with such a sensitive reagent as freshly-prepared 
starch solution. By leaving the tap (21) intentionally open for half an hour, only 
small traces of chlorine could be detected in the bulb (18). This shows that the 
diffusion of the heavy chlorine gas to the top through a very thin capillary into the 
vessel containing carbon monoxide, which is a vacuum for chlorine,* is extraordinarily 
slow. For this reason the method of filling the vessels must not he reversed, 
i.e., we must not fill the quartz vessels first with carbon monoxide and then with 
chlorine from the bulb, nor can we uniformly mix the two gases in the two vessels 
by opening the tap (21), even when the capillary tube is large, a method adopted in 
many similar investigations, but which was found, at any rate in this case, to be 
wrong. 
The Removal of Chlorine from Tubes (7) and (8) and from the Quartz Vessel. 
Removable Pump. (See fig. 3, Table I.) 
Before passing to the description of the methods of preparation of pure chlorine 
and carbon monoxide, a few words must be added as to the mode in which chlorine 
can be completely removed from the vessels before a new experiment is proceeded 
with. The removal of carbon monoxide is a simple matter—this being done by the 
Topler pump, but chlorine cannot be removed by the Topler pump, because even 
small quantities of chlorine instantly attack the mercury. All attempts to protect 
the mercury pump by inserting tubes with precipitated copper or mercury for the 
absorption of the passing chlorine completely failed. This, however, was effected in 
the following manner :—The vessel (M) was connected through (30) with the vessels 
containing chlorine and was heated and evacuated through the taps (29) and (31), 
connected with (15) by means of a Topler and Fleuss pump, and while the tap (30) 
was turned off, the taps (29) and (31) were then turned off and the tap (30) turned 
on. A great part of the chlorine passes from the vessels containing it into the 
* In this research the velocity of combination of chlorine and carbon monoxide, as a function of the 
reacting masses, had to be studied. A horizontal gauge, as used by Bunsen and Roscoe, could not be 
employed, because very great variations in the reacting concentrations or masses of the gases, amounting 
to 70-80 per cent., had to be studied. Thus a mercury manometer had to be employed. To be able to 
carry out this research, in view of the chlorine attacking the mercury, advantage was taken of the 
extremely slow diffusion of chlorine, which in concentrated S0 4 IL is still smaller than into a vessel of 
carbon monoxide, which is a vacuum for chlorine. If the column of the concentrated SO.JR over the 
mercury in the manometer is taken long enough (10 centims.), and care is taken that the filling of the 
quartz vessel with chlorine or carbon monoxide is very slow, so that the concentrated SO 4 H 2 should not 
remain on the walls of the capillary tubes, but have time enough to run down, then we find that the dry 
chlorine will not attack the mercury for days, and even weeks. Sometimes we find after a longer time 
that the mercury meniscus becomes a little dull, without, however, losing its shape, and without the 
mercury losing its mobility, and without interfering with accurate reading. 
