422 Scientific Intelligence. 
mixture of magnesia and sal-ammoniac to avoid the formation of a basie 
chlorid. As a decomposing celi, Bunsen employs a porcelain crucible 
divided into two parts by a diaphragm reaching to half the depth of the 
crucible. In this manner the chlorine set free at one electrode is pre- 
vented from again combining with the magnesium deposited upon the 
other. The electrodes used are of carbon, in the form in which it is 
prepared for Bunsen’s battery ; into the surface of the negative pole 
kerfs are cut to prevent the magnesium set free from floating to the 
surface of the fused liquid and there taking fire. To determine the 
quantity of magnesium formed in a given time, the author introduces a 
rent, so that the latter being observed, the former may easily be calcu- 
lated. Magnesium as obtained by electrolysis is upon a fresh fracture 
sometimes faintly crystalline in large plates, at others fine grained ; in 
the first case it is silver-white and very brilliant, in the last more bluish 
gray and without lustre. Its hardness is nearly that of calc-spar. It 
fuses at a moderate heat: in dry air it is wholly unchangeable and does 
not lose its lustre ; in moist air it soon becomes covered with a coating 
of magnesia. Heated to whiteness in the air it takes fire and burns 
and the fluid allowed to stand over night. ‘The next day the beer was 
found d almost free bitterness, the strychnine having been precipita- 
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