(72) 
stituted for the nitrogroup in orthodinitrobenzene by sodium aicohol. 
ate. It appeared that the existence of constant coefficients of velocity 
was not at all, or very little affected by the presence of water in 
the methyl- cr ethylaleohol, a fact which was explained by the 
circumstance that by far the greater part of the sodium is present as 
alcobolate in mixtures of water and alcohol containing even 50 °/0 
of water. The influence of the water present was however felt in 
the alteration of the numerical values of the constants due to the 
change of the medium; with ethylaleohol the change consisted of 
a diminution of the constants as the quantity of water present in- 
creased, with methylalcohol exactly the contrary took place. 
The influence of water on the reaction under discussion could 
not be followed further than a 50°/) mixture of water and alcohol, 
owing to the ever decreasing solubility of the dinitrobenzene. We 
pointed out therefore the desirability of finding a reaction, which 
would allow velocity determinations to be made, for both alcohols, 
from the absolute alcohol to pure water; the two different curves 
for the two alcohols must necessarily meet in the point correspond- 
ing to pure water, that is to the reaction with NaOH. 
We have discovered such a reaction in the process of the forma- 
tion of ethers from alkyliodides and alcoholates, in the special case 
in which methyliodide is employed; the solubility of this iodide 
in water being sufficient to permit of a determination of the velocity. 
With ethyliodide it was found that, owing to its smaller solubility, 
it was impossible to go further than 30°/, ethylaleohol (70°/, water) 
and 40 °/, methylaleohol (or 60 °/, water). 
The reactions studied are thus: 
I. NaOC,H;+ C sl , IL NaOCH, + C H‚I 
III. NaOC,H; + C,H;I, IV. NaOCH; + C,H;I ; 
to which the change, CH;Il + NaOH =CH30Na + Nal, must be 
added. 
The composition of the mixtures of water and alcohol was changed 
by equal steps of 10°/, between absolute alcohol and water. 
It was at once evident that the reaction-coefficients obtained in 
each experiment might be regarded as constants; with methylalcohol, 
the numbers are .very satisfactory, less so with ethylalcohol, but 
still more than sufficiently so to show the change of velocity with 
the quantity of water present. For reaction I the numbers diminish 
lrom 0.189 for absolute aleohol to 0.0040 for water; for reaction 
