342 



CENTRAL SCIENTIFIC CO., CHICAGO, U. 8. A. 



Nos. 8577-80 (front view), 



Nos. 8577-80 (rear view). 



8577. 

 8578. 

 8579. 

 8580. 

 8584. 



8588. 



No. 8584. 



No. 8588. 



MICROSCOPE, Improved Dissecting. The parts of the block at either side of the mirror are 

 cut out to allow light from the sides to strike the mirror, thus doing away with the neces- 

 sity of the operator facing the source of light in order that the light may strike the mirror. 

 The block is hollow beneath and back of the mirror, forming a convenient receptacle for dis- 

 secting tools and lenses. This is closed by a door which is hinged at the lower edge of the 

 block. This is most convenient because it is not necessary to remove the specimen from the 

 stage or the lens from the holder when a new dissecting tool or lens is wanted. The lens is 

 held in an arm which permits movement from side to side and provides for focusing. A 

 black and white metal background is furnished with each instrument. 



MICROSCOPE, Dissecting, with 9x Doublet $3.30 



MICROSCOPE, Dissecting, with 12x Doublet 3.30 



MICROSCOPE, Dissecting, with 9x Triple Aplanat 6.50 



MICROSCOPE, Dissecting, with 12x Triple Aplanat 6.50 



MICROSCOPES, Spencer Dissecting. An extremely well made, thoroughly serviceable and con- 

 venient instrument at a very moderate cost. It is made with special reference to stability, 

 ease of manipulation and durability. The focusing is accomplished by diagonal rack-and- 

 pinion, moving a solid brass rod, whose bearings provide great steadiness and a very smooth 

 movement of long range, so that lenses of long focus may be used. Two milled pinion heads 

 allow either hand to be used in focusing. An extra large stage is provided, covered with a 

 heavy polished glass plate, 75 mm x 100 mm, easily removed. The jointed lens arm permits 

 the lens to be used over any part of the stage. Plane and concave mirror is furnished. The 

 hand rests are of metal, detachable. In hardwood cabinet. 



No A 



Number of lenses 1 



Type of lens doublet 



B 



2 

 doublet 



C 

 1 



triple 

 aplanat 



9 



27.8 

 24.5 

 14.25 



D 



2 



triple 

 aplanat 



6, 12 



41.6, 20.8 



36.8, 18.4 



18.50 



Magnifying power, diameters 9 6, 12 



Equivalent focus, mm 27.8 41.6, 20.8 



Working distance, mm 15 22, 12 



Each 10.75 11.75 



MICROSCOPES, Spencer Dissecting, similar in construction to No. 8584, with the exception that 

 instead of the rack-and-pinion focusing adjustment it is equipped with a friction sliding tube 

 adjustment. A button at the side of the pillar moves a strong cylindrical lens arm support, 

 whose bearings extend the whole length of the inner surface of the hollow pillar, giving a 

 steady, smooth movement. Without hand rests, in hardwood cabinet. 



No A 



Number of lenses 1 



Type of lens doublet 



Magnifying power, diameters. 



Equivalent focus, mm 



Working distance, mm 



Each . 



9 

 27.8 



15 

 9.00 



B 



2 

 doublet 



6,12 



41.6, 20.8 



22,12 



10.00 



C 

 1 



triple 

 aplanat 



9 



27.8 

 24.5 

 12.25 



D 



2 



triple 

 aplanat 



6, 12 



41.6 20.8 



.36.8, 18.4 



16.50 



8589. METAL HAND-RESTS for use with No. 8588 , per pair .75 



