ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 351 



MICROSCOPY. 



A. Instruments, Accessories, &c* 

 Q) Stands. 



Two Early Microscopes by Andrew Ross (?) — Mr. E. M. Nelson 

 has sent the following account of the two old Microscopes which Mr. J. C. 

 Webb kindly exhibited at a recent meeting of the Society. 



The Microscope shown in fig. 65 is not signed, but we may conclude 

 from the style and finish of the workmanship that it was made by 

 Andrew Ross. It will be noticed that the peculiarly shaped flat tripod 

 foot is precisely similar to that figured by Andrew Pritchard in his 

 Microscopic Illustrations (1838), but we know that Microscopes sold by 

 Andrew Pritchard were made by Ross and Powell, both of whom at that 

 time worked for the trade. To this tripod foot is fixed a tubular pillar 

 holding an extension-rod which can be clamped in any position by an 

 ordinary screw-ring ; at the top of the rod is a compass-joint to which 

 the limb of the Microscope is attached. 



The limb is, in section, an equilateral triangle, the front angle being 

 cut with teeth for stage focussing rackwork ; below the stage is a con- 

 cave mirror. The body is attached to the arm by a screw-clamp, and 

 when a " single " Microscope is required the arm can be turned aside 

 and another arm to hold Wollaston's doublets used in its stead. A 

 fine adjustment is obtained by a direct-acting screw operating on a nose- 

 piece, but without the usual spring; below this nose-piece there is 

 another sprung nose-piece, which is simply a safety device. This 

 separation of the sprung nose-piece from the fine-adjustment screw is 

 a rare form, and at the same time, a very crude idea. 



There are two objectives, one a single non-achromatic of the same 

 date as the instrument, the other a French button combination of later 

 date. The eye-piece is Huyghenian with a double eye-lens, a form 

 first introduced by Benjamin Martin and subsequently employed by 

 Coddington. In design this Microscope looks older than it really is, 

 but we know that this kind of solid tripod foot was introduced in 1837, 

 and this probably is the date of the instrument. 



The second Microscope (fig. 66), which is smaller, although signed 

 " Carpenter and Westley, Regent Street," was probably made by the 

 same hand and about the same time as the first. The foot, which is a 

 little different in shape, has the same peculiar cut to the front toes ; but 

 the instrument differs from the other in having no pillar, the lower end 

 of the limb being attached to the foot by a compass-joint. It, like the 



* This subdivision contains (1) Stands; (2) Eye-pieces and Objectives; (3) Illu- 

 minating and other Apparatus; (4) Photomicrography ; (5) Microscopical Optics 

 and Manipulation; (6) Miscellaneous. 



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