348 A New Dissecting Microscope. l^l^'^SiJi^^fX^^^ 
The dissecting-irough drops into the opening of the stage on 
removing the stage-plate, and is a zinc trough lined with cork at 
the bottom with a glass centre and a separate loaded cork; the 
trough being large enough to take ordinary glass shdes for floating 
dissected objects upon them. The hot-plate fits also into the 
opening of the stage and level with it, the spirit-lamp being placed 
below in the position of the mirror, and the hot-plate is in contact 
with the stage only at a point at the corners, to prevent any incon- 
venient communication of heat ; the microscope arm is turned on 
one side when the hot-plate is used, as well as the bottom mirror. 
The turn-tahle consists of a plate the size only of an ordinary glass 
sHde, instead of an entire circle, and is carried on a long spindle 
passing through the corner of the stage so as to have a very steady 
and free motion ; and the glass-slides are held upon the turn-table 
by a broad india-rubber band at one end ; the microscope arm over- 
hangs the turn-table and serves as a convenient support for the 
hand when making cement rings. The asphalte-varnish and gold- 
size, for cement rings and fixing cover-glasses, are in bottles having 
each a small brush on a handle fixed through the cork and im- 
mersed in the liquid so as to be^ always in good condition for use ; 
and turpentine is kept in a similar bottle with a brush for conve- 
nience of use in cleaning off slides, &c.; also liquid marine glue 
(Mr. Allport's new preparation). The forceps, needles, knife, &c., 
and the dipping-tubes and brushes are kept in two separate drawers ; 
and the stock of cover-glasses, cells, and labels are in a third drawer, 
the glass-slides and watch-glasses being in compartments below.* 
This Mounting and Dissecting Microscope has been ably worked 
out and improved from my designs by Messrs. Field, of Birming- 
ham, and can now be obtained from them at the cost of two guineas 
complete, including all the materials and implements, except the 
compound body and incHned movement of the stand, which is one 
guinea extra. 
* The microscope arm is used as a retort stand for evaporating solutions of 
salts in a watch-glass over the spirit-lamp in preparing crystals as polarizing 
objects, the stage-plate serving at the same time for warming the slide and cover- 
glass; the arm also serves as a filter-stand for filtering the several mounting 
liquids when refilling the bottles. 
