39 



2. * Photo -micrographic Stage (see Fig. 25, p. 55). For photo-micro- 

 graphic and projection purposes it is particularly desirable to be able to impart 

 a very slow motion to the object and simultaneously to rotate the stage round 

 the optical axis of the microscope. 



Both these requirements are met by our photo-micrographic stage. It 

 has a diameter of 100 mm (4 in.) and may be moved in two directions at right 

 angles to each other within a margin of 10 mm ( 3 / s in.) by means of two con- 

 axial millcd-lieads. The amount of the movements is read by two separate 

 scales and verniers. Having no centring appliance, this stage is not inter- 

 changeable with the large mechanical or the revolving vulcanite stages of 

 Stand l a , nor can it be fitted to Stand l b . 



For this reason we supply the photo-micrographic stage only 

 in connection with Stand l c (the Stand for Photo-micrography and 

 Projection). 



The stages specified under 1 and 2 may be fixed in any position by means 

 of a clamping screw. 



3. *Attachable Mechanical, or Small Traversing, Stage (old pattern), 



No. 46, Fig. 17. 



The construction of this stage is based in its essential features upon the 

 principle evolved by Mr. J. MAY ALL junr. (see "Journal Roy. Microsc. Soc." (2), 

 V, 122, 1885). Two sliding pieces, mounted at right angles to, and in immediate 

 contact with, one another, are moved by means of two milled-heads. Their 

 various positions are recorded by scales and verniers. The range of the lateral 

 movement is 50 mm (2 in.), that of the movement from front to rear 30 mm 

 (P/i6 in.). The apparatus may also be used as a "finder" (see Directions for 

 using this accessory). 



Price: Marks 85. . Code- word: Parasito. 



Case to contain stage: Marks 5. . Code-word: Parazonio. 



4. * Attachable Mechanical -Stage (new model), No. 47, Fig. 18. 



The milled-heads which cause the movement of the sliding pieces are 

 con-axial in this pattern of traversing stage and retain their relative posi- 

 tions in turning. The lateral movement may be effected with either 

 the right hand or the left. 



The margin of movement is slightly greater than with the small mechanical 

 stage, No. 46; the area which can be effectively searched measures about 

 60 X 30 mm (about 2 a / 8 X l 3 /ie in -)- 



The peculiar mechanism of this stage, which was designed by Mr. MAX 

 BERGER, the Chief of our Construction Office, guarantees a considerably 

 greater security in the movement of the sliding pieces and fulfils all 

 requirements of a movable stage when applied to the purposes of a 

 "finder". 



, Sena. 



