219 
\/, n. glycol on Yn. boric ‘acid; =" 4.9510" 
1/, n. glycerol Hs (Risks bo) 2) A ee 
Vem pentderyinrol: 4. A BR OS 
eee EeOetechGls js fu. Tis) sow te de en 
‘/, n. duleitol A eS ea He 
we may conclude therefrom that in pentaerythrol, at least two of 
the hydroxyl groups are situated rather favourably, but not by a 
long way so as in the ease of pyrocatechol; that in dulcitol more 
than one pair of hydroxyl groups exert an influence on the boric 
acid; that in glycol, they are very unfavourably situated and that 
they are also unfavourably situated in glycerol although three of 
them are present. This is shown in a still more striking manner 
when we compare the trivalent pyrogallol with glycerol at a some- 
what greater concentration of the alcohol: 
1 n. pyrogallol on */, n. boric acid = 911.3 « 10-6 
fone Slpeprol an er zelle WEDS PO nd 
In the determination of the idlvenes exerted on the conductivity 
we possess a very simple and sensitive method to get some infor- 
mation as to the situation of the hydroxyl groups in regard to each 
other without strongly attacking the molecule and so disturbing the 
existing equilibrium. 
In consequence of the preceding we submit the following suppositions: 
1. If the hydroxyl groups, as in pyrogallol or in pyrocatechol, are 
situated in the same plane and at the same side of the carbon atoms 
to which they are attached and if there is no entering atom as in 
the case of resorcinol, hydrochinone or phloroglucinol, the influence 
is very great. 
2. ‘This influence becomes less when the OH-groups are leaving 
this favourable position. 
The simple glycols as yet investigated by us: aethylene glycol, 
pinacone, propanediol 1,3, butanediol 1,4'), do not increase the 
conductivity of boric acid. 
We surmise that the hydroxyl groups in these molecules repel 
each other and then, in consequence of the mobility of the saturated 
molecule, get situated as far as possible from each other, still in the 
‘same plane but at the opposite side of the carbon atoms to which 
they are attached. 
We will see whether a more extensive experimental material 
confirms these suppositions. 
') Butanediol (1.4) can be prepared very readily by reduction of succinicdiethyl 
ester according to the directions given by Harries for the preparation of methyl 
(2) butanediol (1.4) from pyrotartaricdiethyl ester. 
15 
Proceedings Royal Acad. Amsterdam. Vol. XV. 
