248 APPENDIX I. 



Mr. a. C. Banfield. — Thirty glass transparencies illustrating 



the application of the microscope to low power stereoscopy. The 



subjects shown range in magnification from four diameWs to 

 seventy. 



Mr. J. E. Barnard and Mr. F. Welch. — Quartz and glass 

 mercury vapour lamps as illuminants for the microscope. 

 Professor W. M. Bayliss, E.R.S. — 



(a) Ultra-microscope of Siedentopf-Zsigmondy pattern, 

 showing Brownian movement in colloidal gold. 



(b) Heating chamber for us© with " cardioid " condenser, 

 showing cessation of Brownian movement on gelatin. 

 Messrs. R. and J. Beck, Ltd. — The Beck Standard London 



Microscope to specification of the British Science Guild. Sloan 

 object changer. High-power dark ground illuminator. Beck micro- 

 meter eye-piece. 



Messrs. Bellingham and Stanley, Ltd. — Instruments for 

 measuring refractive indices. 



Improved Abbe ref ractometer ; all British design, enables re- 

 fractive indices of solids or liquids to be determined at average ac- 

 curacy of two units in the fourth place. The partial dispersion C — F 

 can also be measured. The immersion refract ometer shown is iden- 

 tical in principle, but is designed for use with liquids, being suitable 

 for alcohol determinations. Refractive index plays an important 

 part in microscopy, not only for materials used in objectives, but also 

 in the case of various mounting media. 



Messrs. Boots' Pure Drug Company, Ltd. — The use of the 

 microscope in pharmacy and pharmaceutical chemistry. 



Messrs. British Colloids, Ltd. — Colloidal suspensions under 

 dark-ground illumination, to show Brownian movement. 



Messrs. British Dyestuffs Corporation (Huddersfield), 

 Ltd. — Dyestuffs used for staining. 



Basic Colours'. — Acid Colours: — 



Auramine O. Nigrosine G. Crystals. 



Bismarck Brown R.IOO. Orang© G. 



Magenta Crystals. 

 Malachite Green Crystals 



A 25 per cent. 

 Methvl Violet 2B. 

 Methylene Blue 2B. 



Messrs. The Cambridge and Paul Instrument Company, Ltd. 

 — Reading microscope. Microscope used in the accurate cutting of 

 screw threads. Microtomes. 



Messrs. Chance Bros, and Company, Ltd. (Mr. F. E. Lamp- 

 lough). — Optical glass. 



Mr. a. Chaston Chapman, F.I.C. — Some cultivated and 

 ''wild " yeasts in pure culture; the former are used for brewing 

 and distilling purposes; some of the latter are frequently a source 

 of trouble in the brewery. 



INIessrs. Co-operative Wholesale Society, Ltd. (Dr. Geof- 

 frey Martin, F.I.C). — The use of the microscope in the preparation 

 of foodstuffs. 



