ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



397 



Microscope Illumination.* — E. GiRay describes two forms of lamps 

 which he has found very satisfactory. One lamp is a gas lamp and the 

 other an electric lamp. The gas lamp consists of an erect incandescent 

 mantle flame of the usual form, but raised on a stand so as to be of a 

 convenient height. The stand carries a kind of cage-like framework so 

 contrived that an opaque curtain surrounds the upper part of the lamp. 

 The light which passes upwards through the curtain is ignored, but the 

 light which passes under the curtain is made useful to tlie micros- 

 copist by being made to pass through a slab of ground glass before 

 impinging on the Microscope mirror. The framework also supports an 

 opaque glass shade which serves to reflect on to the glass slab much of 



Fig. 62. 



the light which would otherwise reach the ceiling. There is provision 

 for inserting more than one slab, so that the same lamp may easily 

 answer the needs of two or several workers, especially if it be set in the 

 centre of a round table. 



The electric lamp is an adaptation of one of the new Osrarn lamps of 

 only 4-volt tension. This is supplied with two accumulators, and has a 

 current of " 9 ampere. The lamp is clamped on to a pillar mounted 

 on a stand of such a shape that it slides over one of the prongs of the 

 horse-shoe foot of the Microscope and is secured to it by screws. The 

 lamp is thus brought into the usual position of the mirror. The best 

 results were attained with diffused light, the side of the lamp turned 

 upwards having been ground with carborundum powder and a ground 

 glass disk inserted into the diaphragm. This arrangement also secured 



* Zeitschr. wiss. Mikrosk., xxv. (190S) pp. 163-8 (3 figs.). 



