150 
A condition for the ealeulation is, that the nature of the ions 
and in general the constitution of the used compositions are known. 
When this is not the case the method of investigation followed 
by us may still give some indications. Before applying this method 
to the investigation of the acid or alkalic properties of organic dyes, 
we investigated a number of intermediate products. The investigation 
was also extended over several more or less strongly coloured sub- 
stances. It was found possible to take away the colour just before 
the polarimetric measurements by means of norit or of bone-coal 
without lessening the accuracy of the method. In other cases alcohol 
was added sometimes. This changed somewhat the nature of the 
medium, but several compositions that could not be investigated 
owing to their weak solubility, could now be treated. 
Most of the investigated compositions were obtained from KaAnr- 
BAUM at Adlershof (near Berlin). When this is not the case it will 
be mentioned. As further different solutions were primarily coloured 
we paid little attention to the intensity of the darkening caused 
by the action of the hydroxylions on the glucose. The obtained 
analysis numbers will be given here only partly, elsewhere completely. 
The naphtyl-amines. The melting-point of the used «-naphtyl-amine 
was 50°, that of the B-naphtyl-amine 112°. Hydrochloric compounds 
of these amines too were used. The experiment in an alkalic medium 
taught that neither «- nor g-naphtyl-amine bound an alkali, so that 
they do not influence the decomposition of a glucose in alkalic 
solution. In hydrochloric solution the amines in question behaved 
approximately as monovalent bases. 
Ortho-phtalic-acid Cinnamic-acid 
ri me == AN ’ 
| mt M.W.—166 , | En 
— COOH M.W. 148 
NL NF 
Ortho-coumaric-acid a-naphtoic-acid 
—OH COOH 
f= OHSSCH—- COOH ERSTEN 
eed M.W. = 164 ge | op ee 
NS 
a-oxynaphtoic-acid 
OH 
ON 
Nae 
The melting-point of the investigated ortho-phalic-acid was 200°, 
Bd 
MW. = 188 
ry. or 
