296 SECTIONAL TRANSACTIONS.—B. 
HO OH HO OH 
\ x Semi 
C=C C=C 
KS NY 
CO CO 
A 
H2AC6 HGLG 
as resid i H—C—OH = 
| | 
CH,OH CH,OH 
(1) (II) 
It will be seen that the above configurations (projection formulz) are 
identical with respect to the stereochemical arrangement of groups attached 
to the ring and differ only by the reversal of one OH-group in the side 
chain. If this principle holds we should expect also the following, which 
are in course of preparation, to show some physiological activity : /-gulo- 
ascorbic acid and also the /-galacto-, d-allo- and d-erythro-ascorbic acids. 
AFTERNOON. 
Visit to the Laboratories of the Fishery Board for Scotland and of the 
Department of Scientific and Industrial Research, Torry. 
Monday, September 10. 
Jomnt Discussion with Section A (Mathematical and Physical Sciences) 
on The physical and chemical properties of heavy hydrogen (10.0) :— 
Prof. E. K. Riweat, M.B.E., F.R.S.—Introduction. 
Dr. A. FarKas.—Some properties of heavy hydrogen. 
A micromethod has been developed based on the different thermal con- 
ductivity of light and heavy hydrogen. One can estimate by this method 
the relative amount of the molecular species H,, HD and D, and of their 
ortho- and para-modifications in 2-3:10°3 c.cm. of gas (N.T.P.). The 
reaction between H, and D, proceeds in the gas phase above 500-600" C. 
according to both an atomic and a molecular mechanism, but can be catalysed 
at much lower temperatures. The equilibrium constant of this reaction is 
about 4 and nearly independent of temperature. It is shown that when 
H, and D, diffuse through a fine nozzle a separation occurs on account of 
their different molecular velocities. On the other hand, the different rate 
of diffusion through palladium is due to a different heat of activation for 
this process caused by the difference in the zero point energies of light and 
heavy hydrogen. In collaboration with Dr. Harteck it was shown that, 
similarly to the case of ordinary hydrogen, the ortho-para-conversion occurs 
also with D,. From kinetic and equilibrium measurements we can deduce 
the following information concerning the D-nucleus: (a) The Bose- 
Einstein statistics are applicable; (6) the nuclear spin = 2/2; (c) the 
magnetic momentum = 0:5 nuclear magneton. 
Mr. H. W. Metvitte.—Heavy hydrogen : its bearing on problems in 
chemical kinetics in gaseous systems. 
In the investigation of the kinetic behaviour of heavy hydrogen compared 
with that of light hydrogen, the types of reaction may be divided into three 
