556 SUMMAKT OF CURRENT RESEARCHES RELATING TO 



other. The feet on which the instrument stands are made to close 

 together for portability, so that it occupies a space of 12 X 7 X i^^in. 



The slides of the coarse adjustment iit on knife-edges in V-shape 

 grooves, reducing friction, with perfect steadiness and smoothness, 

 and working without loss of time. 



The fine adjustmeut moves the whole of the body of the instru- 

 ment (instead of the nose-piece only), so that there is no change of 

 distance between the eye-piece and object-glass, and obviating the 

 necessity of altering the collar-correction as the fine adjustment is 

 used — the correction being found once for any given object, no further 

 alteration is required. 



The stage is glass and has universal motions, and by a screw- 

 adjustment the friction can be increased or diminished ; it is arranged 

 to take off and be replaced by one with mechanical movements if 

 desired. 



Altogether the Microscope is likely to be one of the most useful 

 forms for those who do not desire a stand of large size. 



Walmsley's Photomicrographic Apparatus. — This simple and 

 inexpensive form of camera (fig. 96), the design of Mr. W. H. 

 Walmsley,* is intended to produce, by the aid of gelatine di-y plates 

 and ordinary lamplight, photomicrographs of a high order of excel- 

 lence, and of almost all transparent objects requii'ing microscopical 

 examination. It will answer equally w^ell for photographing opaque 

 bodies, if the latter be illuminated by the light of the sun reflected 

 from a silvered mirror. 



Any Microscope, monocular or binocular, having an axial joint 

 whereby the body can be inclined to a horizontal position, may be 

 employed. The Microscope is placed upon a base-board 4 feet in 

 lencth and 9 inches in width, upon one end of which is constructed 

 a platform for holding the camera, of such a height that the tube of 

 the Microscope when inclined shall be precisely in the centre of the 

 camera, which is firmly secured to the platform by a thumb-screw 

 beneath. 



The camera box, which is square to allow a lateral turning of the 

 plates, has a removable cone front, and bellows sliding upon a frame, 

 with an extension of three or four feet, which has been found sufficient 

 for all ordinary work, though it could be increased to any desired extent. 

 A simple form of clamp holds the focussing frame tightly at any point 

 of extension. A second front is provided to replace the one carrying 

 the cone, to which any ordinary photographic lens may be fitted, thus 

 providing an excellent camera for copying or other studio or laboratory 

 purposes. The focussing screen is of glass, with an exceedingly fine 

 ground surface, mounted in a hinged frame, which is turned aside 

 when the plate-holder is inserted. This screen is only used, how- 

 ever, in adjusting and centering the object, the final and delicate 

 focussing being done on a sheet of plate glass, as presently to be 

 described. 



* Description kincUy supplied by Mr. Wahnsley. 



