438 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
easy displacement of the lamp while the necessary adjustments of the 
components are being made. 
The electric bulb is of the half -watt type, but made of a special 
mixture of glass which presents an exceedingly fine opal surface. The 
metallic filament is entirely obscured, the opal glass diffuses the rays 
emanating from the filament, and when the surface of the glass bulb is 
sharply focussed in the plane of the object — i.e. the aperture of the iris 
diaphragm, which is practically in the same plane as the surface of the 
electric bulb — there is not any structure or granular matter observable 
in the field of view, consequently no interference with the image of the 
object ; therefore we have an artificial light working under ideal con- 
ditions as required in critical illumination. Under these conditions it 
is claimed that the highest possible efficiency is obtained from the optical 
system of the microscope. The lamp is made by Ogilvy and Co., 
18 Bloomsbury Square, London. 
A New Electric Microscope Lamp for Students’ Use and for 
Routine Laboratory Work. — Yertical electric lamp, designed to give 
the maximum of ventilation with the minimum of reflection. Consist- 
ing of cylindrical hood made of planished steel sheet, brass-coated to 
prevent rusting, mounted upon a heavy cast-iron base having three 
