ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 229 



MICROSCOPY. 



A. Instruments, Accessories, etc.* 

 (1) Stands. 



Improved Compound Microscope by James Mann.f — This Micro- 

 scope (fig. ?)0), which suppHes three steps in the evolution of the modern 

 Microscope, was kindly brought to my notice, says E. M. Nelson, by 

 T. Court. The instrument is figured on a plate in a pamphlet t (dated 

 1751) which accompanies it. The Microscope in the main is obviously 

 a copy of J. Cuff's (1744:), § the improvements consisting in the mirror 

 and its attachment, and in making the instrument portable. The first 

 portable compound Microscope was made by George Adams in 1746, 

 and in this instrument we see Mann's device for adapting Adams's idea 

 of portability to Cuff's Microscope. Very probably this was the second 

 portable compound Microscope. 



There are, however, other and more important improvements : — 

 (1) The mirror is plane and concave, thus predating that of Francois 

 Watkins || ; (2) the mirror is for the first time attached to the limb, and 

 not either to the box or to the foot ; (:>) the distance of the mirror from 

 the stage can be varied, as there are two holes, one above the other about 

 1 in. apart, in the limb ; and the mirror, to which a pin is fitted, can be 

 attached to either of them. The above improvements, of which these 

 are the first examples, have remained to the present time. The limb is 

 attached to the top of the box foot by a dovetail slide ; when the Micro- 

 scope is packed in its box a plain plate of brass is placed in its stead to 

 preserve the dovetail. The bullseye is attached to the right-hand side 

 of the stage instead of the front as in Cuff's. 



The figure in the pamphlet is a copy of Cuff's, for the ribbon on the 

 fish-pan is wound in the same way and there are the same reflections in 

 the various glasses ; the Microscope itself, with the exception of the 

 details mentioned above, even in its ornamentation, is precisely similar 

 to Cuff's. 



There has always been a difficulty in dating Microscopes of this period 

 owing to the uncertainty of the date of Cuff's death or retirement from 

 business. Here we have an authentic and dated copy of one of Cuff's 

 Microscopes in 1751. It is not conceivable that such a flagrant plagia- 

 rism would have been perpetrated. We know from Adams's illustrated 



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

 Illuminating and other Apparatus ; (4) Photomicrography ; (5) Microscopical 

 Optics and Manipulation ; (6) Miscellaneous. 



t Journ. Quekett Micr. Club, ser. 2, xi. (1911) pp. 317-20. 



X Title: "A Description of the Compound (formerly called the Reflecting or 

 Double) Microscope, with great improvements. London made and sold by James 

 Mann, at the sign of Sir Isaac Newton's Head, and Two Pair of Golden Spectacles, 

 near the west end of St. Paul's, 1751." 



§ Journ. Quekett Micr. Club, ser. 2, vii. (1898) p. 116, fig. 23. 



li See this Journal, 1908, p. 143, fig. 26. 



April 17th, 1912 R 



