( m ) 
4. As regards the thermomagnetic examination of polymorphous 
transformations, a discontinuous diminution of 15% of the specific 
susceptibility was found at the transition-point of c-fhallium and 
^-thallium at 234°. But the most remarkable properties are shewn 
by tin: If diamagnetic grey tin is slowly heated, at 32° the specific 
susceptibility (— 0,29) changes almost suddenly (like the density) 
and at 35° passes through zero. Possibly this change would wholly 
take place at the point of transformation (18°) but then at a 
much slower rate. Further heating continuously increased the sus¬ 
ceptibility so that at about 50" the value (+0,03) for paramag¬ 
netic tetragonal tin was reached, which afterwards remained practically 
constant; according to Degens the point of transformation tetragonal 
rhombic tin lies at 161° at which temperature nothing particular 
was noticed; at the melting point (233°) a discontinuity from 
X = + 0,03 to x = — 0,04 once more appeared; the diamagnetic 
liquid metal remained nearly unchanged. 
An extension of these thermomagnetic investigations towards low 
temperatures is in preparation. 
From the above, especially from the conclusions arrived at under 
1 to 4, it seems to follow that Curie’s four corresponding rules are 
certainly devoid of the general meaning, which has rather rashly 
been ascribed to them. At the same time the experimental starting- 
points of Langevin’s theory are evidently undermined; more solid 
and broad foundations for future theories can only be laid with the 
aid of more extensive research. 
Chemistry. — “Studies on Tellurium : 1. The mutual behaviour 
of the elements sulphur and tellurium \ By Prof. F. M. Jaeger. 
(Communicated by Prof. Van Romburgh). 
(Communicated in the meeting of January 29, 1910). 
§ 1. Whilst we are in the main thoroughly informed as to the 
relation of selenium and sulphur, the views as to the mutual behaviour 
of the elements tellurium and sulphur still differ somewhat. Klaproth l ) 
has already investigated this subject. He states that on melting 
together tellurium and sulphur leaden coloured masses are formed 
crystallising in rays, which, on heating, give off sulphur and yield 
a porous metallic looking mass, which he takes to be telluriumsulphide. 
Berzelius -), thirty years later again broached the subject; he found 
that no compounds were formed on melting, but thought that the 
1 ) Klaproth, Crelle’s Ann. (1798). 191. 
2) Berzelius, Gilb.-Pogg. Ann. 8. (1826). 413. 
