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22 PREPARATION AND MOUNTING 
an account here; but the author believes that most, if not 
all, of the same effects may be produced by the employment 
either of a thick plate of metal placed upon the stage, or of 
a thin water-bath, which may be heated by a spirit or gas 
flame, after the glass slide shall have been placed on it. 
They should both be properly fitted with thermometers. 
Of the decomposition of salts by electricity, and their re- 
duction to the metallic state, it is not necessary to speak 
here, but such effects are very beautiful, and the resulting 
crystalization may easily be watched ; 
Dr. Beale speaks very favourably of the inverted micro- 
scope devised by Dr. Lawrence Smith, U.S.A., by which © 
objects may be viewed from their under instead of from their 
upper surface, and at the same time heated (or re-agents 
applied to them) without any risk of dimming or injuring 
the object-glass by vapours thus raised. The optical part 
is so fitted to the base that it may be drawn away from be- 
neath the stage (to make room for the application of the 
lamp, or) for the sake of changing the powers. 
11TH Dryiston. 
It is evident that in all these plans an amount of evapo- 
ration is constantly going on, which will eventually dry and 
so spoil the object, unless obviated. Frey, therefore, describes 
a “moist chamber” invented by Recklinghausen for this 
purpose. It consists of a glass ring, more or less high, 
which has been cemented by its edge to a broad glass slide. 
A tube of thin rubber is then firmly fastened about the ring. 
The upper end of this tube is also fastened around the tube 
of the microscope. In order to keep the place thus enclosed 
saturated with moisture, some small pads of wetted bibulous 
paper, or pieces of elder pith also saturated with fluid, are to 
be enclosed with the object, which in this case need not be 
covered with thin glass in the usual manner. It is con- 
ceivable also that this apparatus may easily be converted 
into a gas chamber, by fixing two small, light vulcanized 
