348 
DR. MEYER WILDERMAN OX CHEMICAL DYNAMICS 
The end of the tube was then opened and a current of chlorine, prepared from 
manganese dioxide (freed from carbonates) and concentrated hydrochloric acid, passed 
through two wash-bottles of water and two bottles of concentrated sulphuric acid, 
was passed over the reduced copper. 
Chlorine combines with copper in the cold, but as the reaction progresses the 
copper and tube become heated from one end to the other. The heat developed is 
usually so great that the cuprous chloride formed melts to a cake. When the contents 
of the tube have become green, the tube is broken, the mixture of cuprous and cupric 
chlorides is powdered and placed in a Jena tube drawn out at both ends. The tube 
is now heated for its whole length to about 250-300°, and chlorine is allowed to pass 
over it for a long time, the tube being shaken from time to time, when more chlorine 
is absorbed. The whole mass is then allowed to cool in the current of dry chlorine. 
From the increase in the weight of the tube and the weight of the copper taken, the 
amount of the cupric chloride formed can be calculated, and, if necessary, the 
operation of passing chlorine over the heated mixture of cupric and cuprous chlorides 
is repeated. There is no necessity for the whole mass to be transformed into cupric 
chloride. A current of air is then drawn through the tube to remove the chlorine, 
for the reason stated above, and then one end of the tube is sealed up. 
Tube (7) with cupric chloride and cuprous chloride thus prepared is now ready to 
be used for the experiment; it is placed on a combustion furnace, one end of it being 
connected by means of a piece of india-rubber tube used for vacua to tube (8), 
containing phosphorus pentoxide, and the india-rubber covered with Crookes’ cement.* 
* It was found that no tube of soft glass could be used, the atmospheric pressure outside pressing the 
glass in at the places where the tube was heated. Thus a tube of hard glass had to be used. This, as 
known, cannot be joined with the soft glass of which the glass cylinder of the quartz vessel and the 
capillary tubes are of necessity made. Since it was found that air (oxygen) and water vapour are just 
the gases which are most fatal for the gas mixture, the heating of cupric chloride in a vacuum was 
inevitable, and no other method could be employed instead. Luckily, the amount of chlorine gas required 
for each experiment was exceedingly small, and only about gram. mol. of cupric chloride had to he 
decomposed for each experiment, i.e., only 1 or 2 eentims. of the tube (7) had to be heated, and, since the 
filling of the quartz vessel with chlorine and carbon monoxide had to be carried out (for reasons given 
above) slowly, and cupric chloride decomposes at a comparatively low temperature, this centimetre or two 
of the tube had to be heated slowly and cautiously with only a comparatively small flame. Tube (7) was 
heated at the sealed end, which is more removed from tube (8), and the glass of (7) is made to meet the 
glass of (8). Under these conditions not only is the glass of (7) and (8), where they meet, quite cool, but 
the tube (7) is so already, being 30 or 40 eentims. removed from (8). The gas passed the draAvn-out cold 
tubes (7) and (8), where they meet, vuth the india-rubber collar on the top, for only about 10 minutes. 
Under these conditions no traces of the action of chlorine uoon the india-rubber collar can be found on 
Jl 
cutting the same, or by chemical analysis. Chemical analysis, hoAvever, can give us little information 
about small impurities AA r hen the quantities of gas are so small as those Avhich I had at my disposal. 
There, however, still remains a superior analysis for impurities, Avhen no chemical or physical method can 
be of any more use, viz., the possibility of getting regular curves and a velocity constant. This analysis 
showed that either the chlorine is absolutely free from any impurities, or that they are so small and of 
such a kind as not to interfere with the phenomena under consideration. 
