1892.] MICROSCOPICAL JOURNAL. 99 



titioner. In its optical performance it is said to be equal to the 

 best instrument on the market. The Beck's, with their uniform 

 work, which has been well-known for half a century, their large 

 works in London having descended from father to son, have 

 maintained an evenness of production which is remarkable. The 

 same objectives and the same quality of eye-pieces are used on 

 this stand that are furnished with the more expensive instruments, 

 and added to the instrument is a fine Abbe condenser with iris 

 diaphragm adjustment, which, by a simple device, can be accu- 

 ratelv centred and raised and lowered by the spiral fine adjust- 

 ment controlled by the large milled head. The adjustments arc 

 all quite simple. 



There are several points in which this instrument is claimed to 

 excel other low-priced microscopes : it is fitted with a substage 

 to which can be applied all the substage fittings, such as poLari- 

 scopes. spot lenses, Abbe condenser, dark well, hemispherical 

 lens. Dr. Willit's prism, and many other substage adjustments. 

 It has the society screw. It is finished with a dark lacquer to 

 prevent the action of chemicals from destroying its good appear- 

 ance. 



The instrument can be used with the highest powers, 1-12 and 

 I -20th being easily focussed. With the use of the Abbe con- 

 denser it is adapted to the examination of bacteria. It has a 

 swinging double mirror, and at the right side of the instrument is 

 a large milled head, by the revolution of which the substage is 

 raised and lowered for the most delicate focus of the light upon 

 the object, and when not in use the entire substage can be thrown 

 out of the focal axis. 



The No. 115, Beck's New Bacteriological Star Microscope, 

 with Abbe condenser and iris diaphragm, two eye-pieces, ^-inch 

 objective and i-6-inch objective, in walnut case, sells for $65.00. 

 The same, but with i -12-inch oil immersion objective instead of 

 I -6-inch, sells for $90.00. 



MICROSCOPICAL MANIPULATION. 



Paper for Cleaning the Lenses of Objectives and Ocu- 

 lars. — The so-called Japanese filter paper (the bibulous paper 

 often used by dentists when filling teeth) is being used for clean- 

 ing the lenses of oculars and objectives. Whenever a piece is 

 used once it is thrown away. It is more satisfactory than cloth 

 or chamois, because dust and sand are not present, and from its 

 bibulous character it is very efficient in removing liquid or semi- 

 liquid substances. 



Use it for removing immersion fluid from objectives, cloudiness 

 or dirt from eye-pieces, glass slips, or thin glass. Water, glycerine, 

 or other fluids can be removed. It is very cheap. It is put up 



