8:^ C. (i. DUNNING ON AN IMPROVED MICUOSCOITC AL TURNTABLE. 



■with the addition of a dovetail groove across the centre, in which 

 work the two sliding blocks AA. To these sliding blocks are 

 attached the clips BB. One of these clips is rigidly fixed at right 

 angles to its guide, the other being pivoted in order that it may 

 adjust itself to any little irregularity which may occur from the 

 edges of the slides not being quite parallel. The ends of the 

 sliding blocks are cut and " sprung," so as to give sufficient tension 

 to secure a firm grip of the slide ; this tension can, of course, be 

 readily increased to compensate for wear. Guiding lines and circles 

 may be ruled on the table for the purpose of centering the slides, 

 but as will be readily seen, any non-central position may be easily 

 obtained even with slides up to two inches in width, thus facilitating 

 the application of the finishing varnish to, or the repair of any slide, 

 the covering glass of which may not have been accurately centered. 



