29 
through the wire which surrounds it.’ As the wire round the fields 
is connected with that of the armature, the current passes round 
these, and in doing so makes them more powerfully magnetic and 
so able to induce a more intense current in the wire round the 
armature. After traversing the fields it makes its way through 
the main circuit and round to the other brush. This brush 
delivers it up to one half of the commutator, and as one end 
of the armature wire is connected to this half, the current can 
flow all through the wire to the other half, and so to the brush and 
round the fields again. As each half of the armature is alter- 
nately north and south for it is made of soft iron, and one brush 
always collects the Electricity due to north magnetisation, and the 
other brush that due to south, a steady and apparently constant 
current is maintained. 
I will now throw on the screen a picture of the Gramme Dynamo, 
and we will see how far its parts correspond with the one I have 
described. 
The armature being somewhat different to Siemen’s H, we will 
will throw that alone on the soreen. 
Marcu 8ru, 1887. 
The meeting took the form of a Conversazoine. There was an 
interesting exhibition of a great variety of objects, which were 
described and explained to the members. 
Electrical Apparatus; by Mr. A. H. Ullyett, and Mr. 
Hambridge. 
Botanical and Zoological specimens by Mr. Walton. 
Miscellaneous specimens by Dr. T. Hastes. 
Dried Australian Plants; a collection presented to the Society 
by Miss Rutt. Microscopes were lent by the President, Secretary, 
Dr. Tyson, Dr. Eastes, and others. 
Mr. Peden, of Dover Road, brought three instruments and 
exhibited Vorticelle and many other living specimens. 
May 3rp, 1887. 
The Secretary was absent through illness. Dr. Fitz Gerald took 
_ the chair and read the following paper: 
WHY THE SHA JIS SALT. 
It has been well said that without the sea the world would have 
remained in a state of barbarism, for civilisation would have been 
impossible. The sea not only united primitive nations, and 
