166 THE AMERICAN MONTHLY [Jun 
this slot would be treated as the source of light and focuss- 
ed accordingly. 
At a recent meeting of the Royal Microscopical Socie- 
ty, Mr. Rousselet exhibited an incandescent electric lamp 
of the Edison and Swan “Focus” type, which has a some- 
what coarse filament not unlike a corkscrew suspended 
horizontally in the bulb, ' This lamp gives an intensely 
brilliant light, and it has on many occasions been used for 
magic lantern purposes. It was recommended that the 
light for microscopical work should be taken from the 
edge of the filament and focussed in the same manner as 
the wick of an oil lamp. The light arranged in this way 
was, however, to my mind too much diffused, notwith- 
standing that a shade was used. On making further in- 
quiry I find that a stand for an electric lamp is made for 
laryngologica] and aural examinations which has joints 
and movements for adjusting in any desired position. In 
the usual type it carries an ordinary eight or sixteen can- 
dle-power lamp, but it will quite well carry the “Focus” 
pattern. If now an enclosing shade be provided similar 
to that described for the Welsbach light above, with an 
aperture which can be treated as the source of illumina- 
tion, an ideal electric light for microscopy is secured. 
This would answer well also for photo-micrography. 
A lamp, somewhat similar to the foregoing, has been 
used by me with considerable satisfaction; though long 
usage has created a distinct prejudice in favor of the $-in. 
wick oil lamp. 
All workers have not electric current available so this 
will not appeal to them, but the majority have gas, and 
where oil lamps are objected to, I would advise a trial of 
the Welsbach light arranged as described above. 
PHoro-MicrograpHy WITH ARC LAmPp.—Trouble is in- 
variably experienced in maintaining the light in one cen- 
tral position, and several devices have been resorted to 
in order to control this. No automatic lamp is really use- 
