6 300 3 
This spitting therefore takes place at the point called above the 
second boiling point. A similar phenomenon is shown by lead oxide 
which on melting also absorbs excess of oxygen but releases it 
on cooling. 
On the other hand it is not shown by copper, either because the 
line CFB cannot be continued up to the maximum, or because this 
maximum is situated below !/; atm. so that in the presence of air 
the absorption of oxygen will cause the formation of Cus O. 
In all these cases, a point corresponding with the first boiling 
point of salt solutions does not appear to exist because before that 
time other vapour pressure lines appear in connection with the fact 
that at lower temperatures the lower or higher oxides are stable. 
As to the exact conditions of their formation much might be deduced 
from existing investigations, which I must, however, pass over here. 
The foregoing may also be applied to the absorption and loss of 
He, CO, and other gases, and to the formation of chemical compounds 
with those gases. 
Chemistry. — “The Enantiotropy of Tin.” (VII). By Prof. Ernst 
Conen. (Communicated by Prof. H. W. BAKHUIS ROOZEBOOM). 
(Communicated in the meeting of December 28, 1901.) 
1. Through the kindness of Prof. PAur of Tübingen who informed 
me that a very striking case of tin plague had occured at Ohlau 
in Silesië, I am in a position to communicate some particulars 
about this case. 
The case owes its importance to the dimensions of the corrosion. 
At my request Dr. HAMBERGER of Ohlau gave me some further 
information about the matter. 
The catholic church in the said village possesses an organ which 
was repaired in the year 1835. While of the newly fitted pipes 
no less then 28 became corroded in a very high degree, the old 
pipes were not affected. The phenomenon was again noticed for 
the first time 18 years ago (1883). The two accompanying illustrations 
taken from photographs show to what extent the pipes have been 
attacked. According to Dr. HAMBERGER the corrosion is still going on. 
It is worthy of notice that the wooden roof of the church is 
situated immediately above the pipes, causing the church to be 
very warm in summer but very cold in winter time. 
The average winter temperature at Ohlau is — 1°,64 C., the 
average yearly temperature + 7°,97 C. 
