A NEW MICROSCOPE ILLUMINATOR. 



By Alexander Silverman 

 (University of Pittsburgh, U.S.A.) 



The device here described has already come into extensive use 

 in the United States. The illuminator* and this paper are submitted 

 for consideration by interested British societies. 



The'Lamy. — This consists of a quarter-inch glass tube containing 

 a single tungsten filament. The tube is bent into a circle of one- 

 inch inside diameter, and one and one-half inch outside diameter. 

 It is made of colourless or blue (daylight) glass, and silvered, so 

 that light is reflected downward from the circular source to the 

 object being examined. The possibility of silvering the entire lamp 

 and cutting a lateral line-slit in the mirror at the smallest diameter 

 is under consideration to determine the possibility of producing 

 through a plane of light a sort of ultra-microscope effect for the 

 examination of bacteria. 



The lamp is operated at 0.9 ampere and 13.5 volts for visual 

 work, and 1.06 amperes and 18 volts for photographic work. Current 

 from an ordinary lighting circuit is utilised, and controlled through 

 a special rheostat (Fig. 1), which contains a push-button swit^'h for 

 the lower current and a spring-contact for the higher one. 



The Holder. — An automatically adjustable support (Fig. 2), 

 provided with three iris-like fingers, controlled by springs, is attached 

 concentrically about the objective. The lamp is held to the underside 

 of the support by two curved prongs and a perforated spring clip 

 which slips over the exhaust protuberance of the lajiip. The 

 terminal wires from the lamp are attached to binding posts which 

 are so constructed that they will also receive the brass pegs attached 

 to the cord coming from the rheostat. These pegs may be inserted 

 vertically or horizontally. 



For general observation the lower portion of the lamp is in a 

 plane with the flat face of the objective lens, but it may be raised 

 or lowered to meet the needs of the operator. 



Binocular Microscopes. — While the lamp-holder is clamped 

 directly to the objective on monocular (Fig. 1), and single-objective 

 binocular microscopes when 16 mm. or higher power objectives are 

 employed, a stage support (Fig. 3) is provided for use with low 

 power objectives and the Greenough binocular microscope. Lateral 

 adjustment of the stage adapter centres the light and vertical 



* U.S. Patents 1,311,185, 1,311,186 and 1,257,287, British Patent 

 125,187, Caniadian Patent 185,283, Italian Patent 48/485, French Patent 

 489,304. Other foreign patents pending. 



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