1888.] cylinders when attracted by an electrified sphere. 181 
water, and when the current was passed the central floats took 
that form, which is exactly that of M19. In cases such as 9 
where there are not sufficient magnets to form two hexagons, 
pentagons, the nearest form, are produced either alone or 
mixed. Or reducing the figures to triangles the perfect form 
is an equilateral triangle which is produced when the numbers 
are great enough and when the pressure is equal on all sides ; 
failing numbers, the triangles of the pentagon with angles of 
72°, 54° and 50° are given. Pressure not being equal, the triangles 
become irregular. 
I give figures 9, 10 and M19 so marked as examples. The 
figures produced by the electrified cylinders are not as regular 
as they might be got with better floats, but it is evident that 
they vary from those given by magnets, only, on account of their 
imperfection, and that they obey the same law and with perfect 
floats would produce identical shapes. 
February 13, 1888. 
Mr J. W. CLARK, PRESIDENT, IN THE CHAIR. 
W. Bateson, M.A., Fellow of St John’s College, was elected a 
Fellow of the Society. 
The following communications were made: 
(1) On Variations of Cardium edule from the Aral Sea. By 
W. Bateson, M.A., St John’s College. 
The author stated that he had visited the Aral Steppe in 
order to see if any structural variations could be found in animals 
living in water of different degrees of saltness which could be 
correlated to those conditions. In the case of the cockle an 
instance of this had occurred. It is well known that the level 
of the Aral Sea has fallen in recent times, and it is certain that it 
formerly stood about 15 feet higher than it now does. The water 
then covered a considerable belt of low lying country to the North 
and Hast of the present shore line. This region is shewn by the 
presence of vast numbers of shells of the cockle, which still lives 
in the Aral Sea. In the area which is now exposed lie three 
depressions, Jaksi Klich, Jaman Klich and Shumish Kul, which 
are now dry lakes with a crust of salt at the bottom. When the 
Aral Sea retreated these basins must have remained for some 
time as isolated salt lakes in which the cockles were confined. 
