la 
Fan. 19, 1882] NATURE 273 
lower arm, from which a thread passes up to a cylinder | bismuth or other diamagnetic body when placed between 
made lighter than water. This cylinder sets itself broad- | the poles of an electromagnet. Here the importance of 
side to a pulsating tambour, behaving as a piece of | the sedzm in determining by its own density the move- 
Lows Poyey 
ments of the body acted upon, is obvious; and it furnishes ; power, or of the nearer one if they are unequally distant. 
an admirable commentary on the views of Faraday and | The effect is like that on a smail suspended bit of iron 
Becquerel on the relation of the magnetic powers of the between two magnet poles of unequal strength, or at 
surrounding medium to the magnetic or diamagnetic | unequal distances. Now when a small heavy body is set 
properties of bodies. 
This particular series cf experiments is most instructive; 
Fie: 5; 
and deserves a little further elucidation. Ifa small heavy | Fic. 6. 
ball hung to a float is acted upon by two pulsating tam- | , : 
bours whose phases are opposite, it is a question in w/éch | pulsating by mctions in the surrounding water it moves 
phase the little ball shall vibrate. Eventually it takes up | through a /ess amplitude than the water would have done 
that of the more powerful pulsation, if they be of unequal | in its place; for if it receive the same kinetic energy from 
