SUMMARY OF CURRENT RESEARCHES RELATING TO 
436 
MICROSCOPY. 
A. Instruments, Accessories, etc. 
(3) Illuminating: and other Apparatus. 
A New Electric Microscope Lamp for Research Work. — Since 
the introduction of the incandescent electric lamp, numerous forms of 
lamp hoods and shades have been designed for use with the microscope, 
none of which have proved entirely satisfactory. In this new model 
there are features embodied which are not to be found in any patterns 
hitherto used for microscope illumination. The hood is of generous 
proportions, and so constructed that it gives the maximum of ventila- 
tion combined with the minimum of reflection, which materially lessens 
the strain and fatigue experienced in long periods of microscopical 
observations. The hood, or holder, takes the form of a vertical cylinder 
made from planished steel sheet having a flat top fitted with a strongly 
made push-bar switch with lamp socket of the standard bayonet catch 
pattern, and provided with twin flexible wire and standard two-prong 
wall-plug. On the front and inside of the lamp hood is permanently 
fitted an iris diaphragm, which is close to the side of the electric bulb : 
this diaphragm serving the double purpose of regulating the size of 
the source of light as required, and enabling the user to project an 
accurately focussed image of the radiant. 
The lamp hood is fitted to a circular base made of cast brass and is 
detachable. At lower edge of hood a slot is cut which fits over a 
clamping screw with milled head, and ensures hood being replaced to 
the correct position of alignment. In front of the circular base is 
attached a small prismatic optical bench carrying two adjustable supports, 
or saddle stands, for supporting a condensing system, iris diaphragm 
and light filter holder. The condensing system holder is made some- 
what after the manner of the typical English substage mechanism of 
the microscope, but of larger proportions, and is fitted with centring 
screws so that the condenser may be accurately centred to the perma- 
nently fixed iris diaphragm, and also may be interchangeable. This 
holder is on a hinged mount that the condenser may be conveniently 
swung out of the optic axis when not required, and a strong spring 
catch ensures accurate alignment when replaced. The light filter holder 
supplied may be of the pattern designed by Mr. J. E. Barnard, 
F.Inst. F.R.M.S., which permits of the use of any size or shaped 
filters, or if preferred the U-shaped pattern to take the Wratten filters 
2 in. square. 
At right angles to the prismatic bench, and attached to the base of 
lamp hood, is a brass bracket terminating in a rod, which latter fits into 
a spring socket forming part of a square block. The square block is 
fitted to and made to slide upon a square upright pillar so as to provide 
vertical adjustments for the lamp, that it may be raised or lowered to 
