26 PHOTO-MICROGRAPHY 



Another convenient arrangement is that shown in Fig. 14, for attaching to the 

 support S in the diagram Fig. 9, p. 14. Practically it is something like the stage of a 

 microscope. The slide is seen in situ and is capable of being moved in two directions 

 by the capstan-headed screws shown in the drawing. A further improvement is to 

 have the whole made to revolve on its axis. It may seem an unnecessary extrava- 

 gance to have an arrangement of this costly description for low-power work ; but the 



Fig. 14 



comfort obtained by its use, and the time saved thereby, must be experienced to be 

 believed. 



Before quitting the manufacture of apparatus, let another board be made about 

 two-thirds the length of Fig. 12, p. 24, to place on the studio stand when required. 

 This should have no support for the object, but should have two levelling screws, 

 one at each end, for purposes to which we shall refer very shortly. 



Development of the plate is considered in the next section. 



Before quitting this portion of our subject, we must mention another department 

 of low-power work which of recent years has been much in demand ; we refer to 

 photographing the culture-tubes used by Bacteriologists at about i to i J diameters, 

 as it is a department almost unique in itself 



Photographing Culture-Tubes.— These tubes in themselves are nothing but 

 test-tubes of about J to an inch bore filled to about ^ of their extent with some 



