PHOTOMICROGRAPHY 



'a' thousand diameters or more, calls for lenses of high 

 ^p^er^^d "gfeat^ perfection, and a microscope and 

 camera with correspondingly delicate movements. 



Photomicrography should not be regarded merely as a 

 method of recording observations, but also as a valuable 

 means of research. Its evidence must therefore be unim- 

 peachable, and this can only be the case when the chances 

 of false images, due to defects in the optical parts of the 

 apparatus or to their improper use, have been eliminated as 

 far as possible. The optical equipment is consequently the 

 most important part of the outfit, and the aim of the 

 designer and maker of the microscope stand, the camera, 

 and optical bench, is to provide a framework which will 

 carry the lenses, and to fit it with mechanical adjust- 

 ments of sufficient refinement to bring them to bear on 

 the object, and allow them to work to their best advantage. 

 This does not involve the use of the most expensive 

 objectives and condensers when slightly less accurately 

 corrected, and consequently considerably cheaper ones, 

 will serve, as they undoubtedly will in the majority of 

 cases ; but it does mean that the accuracy of the fittings 

 and the delicacy of the movements which carry and 

 control the objectives, etc., must be commensurate 

 with the corrections of the lenses, and that the latter 

 be suitable for the work contemplated. 



Although this view of the value of photomicrography 

 is not lost sight of in what follows, the needs of the worker 

 with restricted capital to outlay also have consideration. 

 An endeavour is made to show how a considerable part 

 of the apparatus can be made or adapted, and in the 

 descriptions of camera, microscope, and illuminating 

 system, the items which are luxuries, or refinements that 

 may usually be dispensed with, are differentiated from 

 those that are absolutely necessary. 



Horizontal Cameras. The Baseboard or Optical 

 Bench. There are two ways made use of for setting 



