| APPENDIX. 145 
The Microscorr. These may be had in the form of simple 
lenses, from Is. 6d. to 7s——Or mounted in brass as a com- 
pound and single Microscope, from £1 16s. to £7 7s. 
| he Microscope is a very generally useful and interesting | 
instrument to the observers of nature, and particularly to the 
Botanist, the Cristallographist, and Mineralogist. 
Great improvements have been made of late years by the | 
| use of garnet in forming lenses of very high powers. These 
are now made so high as jog of an inch focus. 
The Spherical, or bird eye object glass, by Coddington, 
forms a very fine compound or single Microscope, having a 
large field, great distinctness, and very high power, 
The Microscope doubled, prepared by the late Dr Wollas- 
ton, forms also a very powerful instrument, with these lenses. 
The minute lines on the scales of the wing of the White But- 
terfly and Podura, distant from each other less than the g-o00 | 
of an inch, are most distinctly seen. 
All these forms of lenses are attached to the best Micro- 
scopes ; also Micrometers divided upon glass to iow of an inch, 
by which very small objects may be measured. 
Batance, for ascertaining the specific gravity of minerals; 
may ‘be had good, of a small size, for £1 Is. 
Broweess, for fusing minerals, from 2s. te 8s. 
MInerRALocicaL Hammers, of various sizes. 
Forceps, PLatrinum Cups, CaLuirers, ParatLet Ru ces, and 
ProporTIONAL Compasses, &c. &c. 
