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VI. — On a Simple Revolving Ohject-Holder. 

 By Washington Teasdale, F.K.M.S. 



{Read 10th December, 1879.) 



The growing tendency of specialists in late years to make type 

 slides of allied objects, induces me to suggest a mode of displaying 

 them, which I have found very convenient for illustrating a con- 

 nected series of low-jiower objects. The idea of a revolving object- 

 holder, although not a new one, has not hitherto been worked out 

 in a simple and satisfactory form for general adoption. 



The one here described was roughly made by me and exhibited 

 at a conversazione about three years ago. 



Fig. 6 represents the " slide " itself, which is a disk, 6 inches in 

 diameter, of cardboard, wood, ebonite, or other light and suitable 

 material, pierced near its periphery with say twenty-four holes 

 ^ inch in diameter ; this is cemented upon another disk of equal 

 size, of black cardboard for opaque objects and glass for transparent 

 ones. 



Fig. G. 



To support this I use a light triangular frame, preferably of 

 close-grained, well-seasoned wood, and fixed to the stage of the 

 ]\Iicroscope by a stiff brass clamp, furnished with a milled-head 

 clamp screw passing through a slot, and having a circular fork to 

 allow to pass the usual l^-inch sub-stage tube of the cheaper 

 class of instruments. 



As a cover to preserve the objects from dust and allow only one 

 of them to be seen at a time, I provide another light disk, slightly 

 smaller, say 5.^ inches diameter, which may be made a very neat 



