( 467 ) 
Erschütterungen in der Art ab, dass nur durch Schwingungen von 
bestimmter Wellenlinge dic Atome in Mitschwingungen versetzt, 
dadurch aus ihren labilen Gleichgewichtslagen weiter als gewöhnlich 
hinausgeführt werden und dann in stabile Lagen iibergehen.” 
Although this view appears somewhat vague, I as already stated, 
decided to subject ordinary tin to vibrations below the transition- 
temperature. 
As I did not know whether organ pipes of a definite tune had 
shown a stronger corrosion than others, I chose as a source of 
vibration a CHLADNI plate which gave an intense rattling sound. 
The accompanying reproduction of a photograph represents the 
apparatus : 
To the right stands the iron plate kept in strong vibration by 
two copper hammers. These are attached to an excentric which 
is rapidly whirled by means of a cord, by a Hernrict hot-air motor. 
The whole apparatus which was placed in a cellar was exposed 
during the experiment to a temperature varying from -++5° to +12°, 
therefore below the transition point. The plate was kept vibrating 
day and night for three months. The sheet of tin was attached to 
the plate by means of copper wire. 
As already stated, no inversion of the tin had taken place. 
If a place were at disposal where the temperature could be kept 
for a long time below zero, it would be an easy matter to make 
a comparative experiment by attaching to the plate a dilatometer 
filled with tin and comparing it te a second one, which had not 
been subjected to vibration. 
5. Statements found in older literature and communications 
made to me by different colleagues induce me to study the be- 
haviour of antimony, aluminium, manganese, silver, copper and 
lead from the same standpoint as tin. 
Amsterdam, February 1900. 
Chemical Laboratory of the University. 
Physics. — “On Phenomena on the Sun considered in connection with 
Anomalous Dispersion of Light’. By Prof. W. H. Juurus. 
(Will be published in the Proceedings of the next meeting.) 
