252 
hydrochlorides of: temperature 4 
aniline 25° 2.44 X 105 
p. anisidine . 8.08 « 10-6 
p. bromaniline AS 1.14 Xx 10-4 
p. chloraniline 258 8.56 « 10-5 
m. nitroaniline . 3.01 X 10-3 
0. 2 a a Bit 
p. 4 es 5 958% 1053 
m. toluidine 5 1:82 1078 
0 7 ss 3.45 X 10-5 
p. re 4 1:58’ 108 
He executed his determinations at 20° and the result was libera- 
tion of nitrogen and formation of free HCI: 
RN,Cl + H,O— ROH + HCI + N,. 
At the same time, as he could only work in a weakly acidified 
medium, formation of diazo-amino-compounds (especially at 20°) will 
take place. As SCHUMANN himself states, this amounts to several 
percentages in the case of p-bromaniline. Therefore also this method 
will not yield reliable results. 
After them Tassiur *) occupied himself with the study of the 
diazotisation reaction. He follows the progress of the diazotisation by 
determining after different periods the quantity of diazonium salt 
formed. This diazonium salt namely may be-coupled in weakly 
alcaline medium with ScHAFFER’s salt. 
Then he measures the solutions coloured from red to orange with 
the spectrophotometer of Féry in the green-blue part of the spectrum 
comprised between the marks 180 and 200 of the micrometer, 
(sodium line at 50) corresponding with 4, = 4500 and 2, = 4300. 
He sums up his results in the following conclusions: 
1. The diazo reaction is bimolecular. 
2. Increase of the quantity of acid does not increase the rate of 
diazotisation of aniline. 
3. The diazotisation of sulphanilie acid goes quicker when the 
concentration both of nitrite and amine is raised. 
4. The diazotisation of sulphanilic acid is accelerated by an 
excess of nitrite. 
5. The stability of the diazo solutions may be mutually com- 
pared by the help of his method. 
We cannot refrain from subjecting his treatise. (Bull. Soe. Chim. 
Jan. 1920) which gives a review of his researches, to criticism. 
