31 
connected with them will oscillate concordantly. If on the 
other hand one piston goes in while the other comes out, 
the respective spheres connected with the air-pumps will 
oscillate in opposed phase. The same will take place with 
the pulsating drums. 
When these spheres and drums are allowed to oscillate 
and pulsate rapidly in a vessel of water, they are found to 
attract each other if they vibrate in accord, and to repel each 
other if the vibrations are opposed. Nor is this all, for 
Professor Bjerkness, by carefully modifying his apparatus, 
which has been very imperfectly described above, has been 
able to imitate all the phenomena of magnetism and para- 
magnetism, but always in an inverse way. 
Many phenomena of statical and dynamical electricity can 
also be imitated by these vibrating bodies, but likewise in 
an inverse manner. 
The whole subject has been investigated mathematically 
by the Professor, and the Jaws which govern the attractions 
and repulsions of these vibrating bodies have been shown to 
be in accordance with his formulae. 
General Meeting, November 29th, 1881. 
R. Angus Smith, Ph.D., F.R.S., &c., in the Chair. 
Mr. Richard Peacock, of Gorton Hall, Manchester, and 
Mr. Edmund Salis Schwabe, of 41, George Street, Manches- 
ter, were elected Ordinary Members of the Society. 
