The Microscope in the Paper-Mill. 
259 
Chemical. 
“ Anleitung zur mikrochemischen Analyse.” — Behrens. 
“ Mikrochemishe Analyse.” — Behrens; Kley. 
“ Elementary Chemical Microscopy.” — Chamot. 
“ Beactions Microchemiques.” — Element and Renard. 
Miscellaneous. 
“ The Principal Starches.” — Griffiths. 
“ Rock Minerals.” — Iddings. 
“ Minerals and the Microscope.” — Smith. 
“ Metallography.” — Desch. 
“ The Chemistry of Colloids.” — Taylor. 
“ Micro-Organisms and Fermentation.” — Jorgensen. 
“ Iron Bacteria.” — Ellis. 
Notes on Microscopical Equipment. 
1 . More than one-half the microscopical work required in the paper- 
mill laboratory may be performed with a simple stand of heavy 
construction, having a large stage, fitted with a good rack and pinion 
coarse adjustment only, and equipped optically with the best 16 m.m. 
objective procurable, and X 10 eye-piece. 
2. For other work this may be supplemented by a heavy laboratory 
stand such as is generally employed for bacteriological microscopy. 
Optical equipment : Abbe condenser, three objectives, viz. 30 to 40 m.m , 
16 m.m., and 4 m.m., two eye-pieces, X 6, X 10. 
3. Accessories : a simple microtome, simple dissecting microscope 
and accessories, usual reagent bottles and mounting equipment, polari- 
scope, dark-ground stops to condenser, and coloured glasses. Micro- 
meter. 
4. For research work I use three stands. For chemical work a 
stand as described in (1), fitted with tourmaline plates for polarized 
light. For examination of fibres and minerals under polarized light a 
small mineralogical stand. For high-power work and photo-micro- 
graphy a large universal stand with every mechanical refinement of 
adjustment. 
5. Optical equipment for research work. In addition to the fore- 
going, 6 m.m. or 8 m.m. and 2 m.m. semi-apochromatic objectives, a 
full set of eye-pieces up to X 15, projection eye-piece, achromatic^ 
immersion condenser, polariscope, dark-ground immersion condenser, 
illuminator for opaque objects, micro-spectroscope, a good oil lamp 
and light filters. Mechanical accessories : a photo-micrographic bench 
and camera, a good microtome, and the usual minor equipment as 
required. 
6. Although extensive and expensive equipment is required for 
exhaustive work, it should be remembered that the bulk of all micro- 
scopic work is done with the simplest equipment possible. Refined 
equipment and special accessories should be kept in the background 
and only used when absolutely necessary. Speed and skill in manipula- 
