201 
ethylene glycol 0.14 
propane diol 1.2 0.44 
Z 1.3 0.026 
x-monochlorhydrine 0.28 
glycerine 0.77 
cis-cyclohexanediol 1.2 0.15 
trans- s ee 0.000 
The study of the cyclic glycols has supplied an important support 
to the efficiency of the dynamic representation. 
In the cyclo-pentane-diols the five carbon atoms lie in one plane 
almost without tension when we assume that the directions of 
affinity make an angle of 109°28’ with each other. In the cis-isomers 
the OH-groups lie almost in one plane with the C-atoms, to which 
they are bound, hence very favourably for boric acid and acetone, 
as has appeared from Van Loon’s investigation. 
In the trans-diols the position is very unfavourable. In consequence 
of the five-ring the position of these OH-groups can never become 
favourable without the ring being broken. Indeed there was no 
question of the formation of an acetone compound. 
The absence of the acetone-compound in this trans-diol and in 
the trans-hydrindene diol 1.2 is also the proof that when the OH- 
groups are prevented from getting from time to time into or 
almost into one plane, no five-ring is formed. (see above). 
‘At the time it was found that cis-cyclohexane diol 1.2 has no 
influence on the conductivity of the boric acid. This had led me to 
conclude already then that this six-ring must be assumed to havea 
certain suppleness, through which the hydroxyl groups would get 
somewhat further from each other than would have been expected, 
if the six atoms of the ring lay permanently in a plane. 
The equilibrium: glycol + acetone Z acetone compound + water 
corroborated on one side this view, as its position is almost as 
unfavourable as with the ethylene glycol (see above). 
On the other hand it corroborated our dynamic view: The acetone 
compound is formed; hence the hydroxyl groups must now and 
then lie in or almost in the same plane as the adjacent C-atoms. 
