2138 



Journal of Applied Microscopy 



board, slide carrier, etc., are attached to rectangular metal frames by two pins 

 which slip into corresponding holes in the lower portion of the accessories, and 

 by means of a spring catch with corresponding post in the upper side, thus by 

 simple release of the knob K, Fig. 2, any of these parts can be instantly detached 

 from their supports. 



The Condenser System for collecting the light and focussing it upon the ob- 

 ject has received special attention, and a new condenser system devised, consist- 

 ing of a meniscus convex lens which is placed next to the radiant, its concave 

 surface facing the light. By this means a greater number of rays are collected 

 and passed forward than in the case of condensers having a piano convex lens 

 next to the light, and a flatter field, with the least chromatic aberration, is also 

 secured. In combination with this meniscus convex lens are two piano convex 

 condensing lenses with their convex surfaces facing and separated by a consid- 



FiG. 2. — Detail of construction of supports for bellows, 

 object, lens, board, slide carrier, etc. 



Fig. :!. — Section of condenser and 

 water cell. The condenser is a 

 triple system between the two 

 anterior elements of which the 

 water cell is placed, securing the 

 maximum absorption of heat rays 

 with the minimum loss of light. 



erable distance. This is made possible through the use of the meniscus convex 

 lens in the rear of the combination, and its object is to allow the placing of a 

 water cell for absorbing heat rays between these two lenses, as, in this position, 

 the light rays pass through nearly parallel, producing no distortion of the field 

 and practically no loss of light through reflection from its surfaces. The water 

 cell is composed of ground and polished glass sides mounted in a metal ring 

 rendered water-tight by a rubber packing ring held in position by a screw ring 

 on either side. These rings are removed when desired in order to clean the 

 glass plates by means of a key, which renders their removal a very easy matter, 

 thus allowing the cell to be kept always in good condition. The cell is kept in 

 a vertical position when placed upon the table by means of two small metal feet 

 which bear upon the table and is filled through a circular aperture at the top into 

 which two tubes are screwed, allowing for expansion of the fluid as it becomes 

 warm, and also permitting the attachment of two rubber tubes so that a stream 



