14 PEACTICAL PHOTO-MICKOGKAPHY 



is heavy and solid, and specially designed to avoid flexure 

 of any of the parts during work. There are three different 

 models of it made ; the illustration shows the largest and 

 most elaborate of these. The instrument can be clamped 

 when in a horizontal position, and is then perfectly steady. 

 The sub-stage has in this model both coarse and fine 

 adjustment. 



Fig. 4 shows a type of stand recently introduced which, while 

 maintaining the characteristics of most Continental models, has 

 been provided with a foot of the English type, to give greater 

 stability when the instrument is inclined or is in a horizontal 

 position. It has a revolving stage, and also centreing-screws ; 

 and there are the usual adjustments for centreing and focussing 

 the sub-stage. The alteration of this model in the direction of 

 the English type of foot has unfortunately not been carried 

 out to its full extent, as the spread of the three supporting 

 points is not quite so great as it might have been. Otherwise 

 the instrument is a good one, is of moderate price, and will 

 be found to answer its purpose under any ordinary conditions 

 of work. 



The Eesearch Microscope, by J. Swift & Son, is a well-designed 

 and well-constructed instrument of moderate price, which has 

 all the required adjustments to object-stage and sub-stage. 

 Except in the design of foot it is of the Continental type. It 

 possesses a large stage with a mechanical motion which is so 

 designed that it has a very wide range. In common with 

 most instruments made by English firms of this type it is well 

 balanced in any position. 



The Koyal Microscope, by W. Watson & Sons, Ltd., is 

 distinguished by the method of attaching the stage to the other 

 portions of the instrument. This has been designed with 

 the object of getting the utmost rigidity, and of avoiding any 

 movement of the stage when high powers are used. The 

 limb carrying the stage and the sub-stage is in one solid piece. 

 In general it is constructed very much on the lines of the 

 Van Heurck model, but it is simplified in certain directions to 

 provide a cheaper and yet efficient stand. 



The New Model D.P.H. Microscope, made by C. Baker 

 (Fig. 5), is a stand of moderate price and is of a suitable 

 design for photo-micrography. It is carried on a limb cast in 



