( 618 ) 
A 
Zn + — (Zn SO, AH,0) + Hg, 80, = 2Hg +; Zn 80,. 7 H, 0. 
liquid solid 
and 
Zn + ie (Zn SO,. a H,0) — He; SO, = 2 Hg a. — Zn SO, 6 H, O 
liquid solid 
in which <A, or a, represents the number of mols. of water which 
accompany one molecule of ZnSO, in the saturated solution at the 
temperature of the cell. 
3. It has been demonstrated that calculations based on the old 
view lead to utterly faulty results. 
4. The value of Z, in the equation of GrBBs and v. HELMHOLTZ 
is calculated by means of the new equation. For the CLARK-normal- 
cell in which undissolved Zn SO,. 7 H,O is present the calculation 
gave: 
at 18°C. ZE, = S&42% calories 
whilst experimentally the value A= Si490 calories was found 
or, the calculation gives as temperature-coefficient at 18°C. 
— 0,00120% Volt. 
whilst experimentally — 0,001235 » 
was found. 
For the CLARK-cell containing undissolved Zn SO,.6H,0, the 
calculation at 15°C. gives LE, = 45459 calories, 
whilst experiment gives EL, = 43693 jd 
Amsterdam, University Chemical Laboratory, 
April 1900. 
Chemistry. — “Studies on Inversion” (First Part). By Dr. Ernst 
COHEN (Communicated by Prof. H. W. BAKHUIS ROOZEBOOM). 
1. A few years ago (1896) it was stated by Rayman and 
Sure in a paper on catalytic hydration by metals‘), that when 
cane-sugar is dissolved in very pure water (conductivity 0.7 X 10-°) 
and exposed in platinum vessels to temperatures over 80° C. a 
decided inversion takes place which proceeds with a steadily increasing 
velocity. 
') Zeitschrift fiir phys. Chemie 21. 481 (1896). 
