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On a New Universal-motion Stage and Object-holder. 



By Robert G. West. 



CRead Mvemher 28, 1879.J 

 PLATE II. 



We are all familiar with a number of bodies wliich, when seen 

 obliquely, show some features of colour or structure that differ from, or 

 are invisible when the substances are viewed perpendicularly to their 

 surfaces. Instances of this peculiarity are to be found among 

 minerals, crystals, wings, scales, and other parts of insects, and in 

 close rulings or markings on glass, metal, or other substances. To 

 -provide for such bodies an oblique presentation to the microscope 

 objective, and to permit their examination on several sides, various 

 contrivances have been devised. The oldest and best known of 

 these is the stage-forceps. This, however, only permits rotation 

 in one plane ; and, in one setting of, say a cube as the object, will 

 only present four sides and four edges. It is, moreover, inapplicable 

 to objects mounted on slides. Professor Smyth, of New Orleans, 

 has contrived a safety-stage which incidentally admits a certain 

 degree of inclination. Messrs. Beck's beautiful little disc-holder 

 presents five sides and eight edges of a cube, but is unsuited for 

 slide-mounted objects. Mr. Zentmayer, of Philadelphia, makes a 

 microscope with its principal stage tilting in one plane, and this, 

 combined with the rotation of the stage, presents successively to 

 view all parts of an object, except that by which it is attached to its 

 mounting. This is, however, a costly and perhaps rather a cumbrous 

 arrangement. 



In the last two devices some movements have to be obtained by 

 compounding two motions. This is avoided in Mr. Morris's object- 

 holder, which consists of a base-plate to rest on the stage of the 

 microscope, which base-plate is provided with a ball and socket 

 joint, carrying, by means of a short stem, a table or a tray to 

 receive a slide or a disc-mounted object. By this apparatus an 

 object may be rotated, and, within certain limits, inclined freely in 

 every direction ; but it has the very serious drawback that, with 

 the exception of rotation of the carrier in a horizontal position, every 



