1454 
of nitrobenzene and 7,2 gr. of benzophenone. The temperature was 
kept at 65—66°. 
After an hour the condition was as follows: 
Weight zinc blank experiment: 14,08 gr. Generated hydrogen : 
45 ec. (temp. 14°. Barometer 770 mm.). 
Weight zine nitrobenzene experiment: 10,47 gr., generated hy- 
drogen: 142 ce. 
Weight zine benzophenone experiment: 14,19 gr., generated hy- 
drogen 8 ec. 
Here too benzophenone gives a retardation, it appearing at the 
same time from the comparison with the hydrogen generated in the 
blank experiment that part of the hydrogen has been used for the 
reduction of the benzophenone. It seems, therefore, that the nature 
of the surface has no influence on the qualitative result 
According to the way indicated sabove it is further possible to 
take in these experiments more intricate systems, in which through 
coaction reactions are brought about or accelerated. Thus in the mixture 
of metal, hydrochloric acid, and nitrobenzene, the hydrochloric acid 
can be replaced by a feeble acid, as acetic acid, and a salt of 
bydrochlorie acid. 
Then a coaction takes place between four compounds: 
1. Copper with 50 ec. 80°/, acetic acid and 5 gr. CaCl,. 
Decrease 0.180 gr. 
2. Copper with as above, and 5cc. nitrobenzene. Decrease 0.065 gr. 
3. Copper with 50 ee. 70°/, aleoholand 5 gr. CaCl,. Decrease 0.015 gr. 
4. Copper witb alcoh. as above and CaCl, as 
above, and 5 ce. nitrobenzene. Decrease 0.005 gr. 
5. Copper with 50 ce. 80°/, acetic acid and 5 gr. 
CaCl, and 5 ce. nitrobenzene Decrease 0.245 gr. 
Similar coactions, the explanation of which rests likewise on the 
considerations given above are met with in the oxidation of organic 
compounds, and can be most clearly shown by the study of the 
velocity of dissolving of metal-peroxides in acids whether in presence 
of oxidyzible compounds or not. Experiments on this subject are 
still in progress. 
It appears from the above preliminary experiments that there is 
a cooperation, a coaction between metal, acid and reducible com- 
pound, which is to be explained by this that a certain mutual 
activation of the components must take place if the reduction is to 
appear in a considerable degree. This appears to be the case both 
in alcoholic and aqueous acetic acid solution, and in anhydrous 
acetic or paraffin. 
