7€2 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



pillar, supported on a circular base, and of two arms. One arm carries 

 the lens, the other the object-holder. Both arms are fitted with a ball- 

 and-socket joint. The lens arm has also vertical and horizontal move- 



Fig. 10(5. 



ments. This object-holder can be raised or lowered along the pillar, 

 and its outer end is covered with cork ; this part of the apparatus can 

 be rotated and also pushed to and fro. The apparatus can be supplied 

 with lenses having magnifications of from 10 to 35 diameters. 



(3) Illuminating: and other Apparatus. 



Artificial Light for the Microscope.* — C. J. Chamberlain states 

 that excellent illumination is obtainable by means of a hollow sphere 

 filled with liquid. The globe should be made of the finest flint glass, 

 have a diameter of G in., and be mounted in a black frame. The 

 liquid content mostly used is a weak solution of ammonia copper sul- 

 phate, made by adding 50 c.cm. of ammonia to 25 c.cm. of 10 p.c. 

 solution of copper sulphate, and then adding enough distilled water to 

 fill the globe. If the solution be milky more ammonia must be added. 



The best source of light is an incandescent gas burner, so placed 

 that the rays will be focussed on the mirror of the Microscope. With 

 less powerful lamps a reflector is required. 



Apparatus for Examination of Ultra-Microscopical Particles.f — 

 (1) In Solutions.— The firm of Carl Zeiss have prepared the apparatus 



* Journ. App. Micr., vi. (1903) pp. 2GG3-5 (2 figs.). 



t Catalogue, Besclireibung der Einrichtungen zur Sichtbarmachung ultramikro- 

 skopi8cher Teilung, 1904 



