Conversely, we might make use of this method to ascertain the 
occurrence of a catalytic reduction. 
The electric conductivity of hydroxy-hydroquinone and of the 
mieture hydroxy-hydroquinone + 0.5 H,BO,. 
In a previous determination, carried out by one of us with the 
co-operation of Mr. BRACKMANN, there was found with this orthodihy- 
droxy derivative of benzene a small negative influence on the electric 
conductivity of boric acid (Ree. 34, 277 [1915] ). 
As we mistrusted this unexpected result and had reason to suspect 
that the tribydroxybenzene was not sufficiently pure, we have repeated 
the determination taking care to purify by repeated recrystallisation 
from ether the polyphenol prepared from the quinone via the tria- 
cetate (B 31, 1248 [1898]: Rec. 34, 277 (1915). On shaking the 
ethereal solution, while cooling, with animal chareoal it could be 
obtained almost colourless: M.p. = 140°.5. 
The conductivity was determined in the manner frequently described. 
C = Capacity of the resistance vessel = 0.276; 7 = 25°. 
: Specif. conductivity of 0.5 m. H3BO3 = 28> 10—® K.Hb. 
| Conductivity < 105 = K Conductivity increase 
(== > rd Ag a 
System R | Reading on scale| __ ©x(1000 -a) A = Knixtures K(CsH2(OH)3 
| | ha + K4,BO.) 
| 5000 | 531.5 | 48.7 | 
| | 
0.5 m. hydroxy- | 6000 487.0 48.5 
hydroquinone | | 
~ | 7000 | 449.1 48.4 
500 | 580.8 399.6 | 
Ob 700 496.7 309.5 | 322.4 
“L0.5m.H,BO, | | 
900 | 435.4 397.6 | 
1000 | 588.7 192.8 
025 | 1500, 488.3 192.8 | +155 
-++0.25m.H3BO3 | 
| 2000 417.2 192.8 | 
If we compare the value of the conductivity of the 0.5 molar 
hydroxy-hydroquinone + 0.5 m. H,BO, solution with that of the 
corresponding solutions of pyrocatechin and pyrogallol (899.6 with 
555.2 and 608.9, respectively) this is certainly somewhat smaller 
but positive and of the same order of quantity, so that the hydroxy- 
hydroquinone is connected quite normally with the other orthodihy- 
. droxybenzene derivatives. Delft, March 1916. 
106* 
