Smith, on a Mounting Instrument, 
3 
down in the centre of the flat plate_, a spring (g) keeps the 
two arms apart, and, where permanent pressure is required, 
a loose ring (e) (or, if found more convenient, a small screw) 
keeps the upper arm in a fixed position by sliding it up as far 
as it will go. 
To use the instrument the object to be mounted is placed 
dry on the glass slide, which is put in the plate or holder, 
and a thin glass cover being placed on it the upper arm is 
pressed down, bringing the small disc upon the thin glass 
cover and holding it in its place during the process of 
mounting a sufficient quantity of balsam being put at the 
side of the cover, the instrument is held over the flame of a 
lamp and sufficient heat applied to melt the balsam, which 
runs in by capillary attraction. 
The advantages ofi*ered by this process being the facility 
with which specimens can be mounted, as well as that objects 
of great delicacy can be placed on dry, and the balsam then 
run in without in any way disturbing their several parts ; a 
slight extra pressure also frequently serves to disperse the 
air-bubbles entirely from the specimen. 
In the mounting of Marine Algae, &c., by this process, with 
a gelatine medium (Deane's), the specimen can be laid on the 
glass with a small quantity of water, and properly arranged 
in it, the glass cover being then put on, and a sufficient 
quantity of the medium placed at the side of it ; when heat is 
applied, the gelatine drives out the water and leaves the object 
mounted. 
