ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 655 



distinct improvements. The following points may be noted : — 1. It is 

 provided with a fine-adjustment which focuses the lens and body, not 

 the stage. 2. The instrument is inclinable. 3. The stage has lateral 

 movement on a pivot. 4. The pillar is mounted excentrically on its 

 oval base-plate and is capable of rotation, which gives the Microscope 

 greater stability in different positions. 5. It can be folded for portability. 

 6. A clip is provided to clamp the slide. This is the earliest known 

 example of slide clip. 



Described and figured in Journ. R.M.S., 1898, p. 675. 



Lent by Mr. E. M. Nelson. 



Class 3. — Compound and Simple Combined. {Complex Instal- 

 ments, shoiving the development of the Stand, and illustrating the 

 use of the " Double " Microscope, in combination with Simple 

 Microscopes, prior to the introduction of the Achromatic Objective. 



JOHN CUFF'S Compound Microscope. Invented about 1744. 



Type — Alternatively Simple or Compound, uncorrected. 



The inventor of this model made a distinct improvement in the 

 mechanical construction of the Microscope, and it forms an important 

 link in the evolution of the instrument. The stand is firmer and more 

 rigid, and altogether more handy, whilst the stage is more accessible ; the 

 fine-adjustment applied to the body has greater delicacy. After Cuff's 

 death this model was made by various opticians, such as Adams, Dollond r 

 Nairne, etc., with various additions and improvements. 



Described by Baker, "Employment for the Microscope," 1753, 

 pp. 442-6. 



Presented to the Societv Nov. 16, 1904. See Journ. R.M.S., 1904, 

 p. 727. 



BENJAMIN MARTIN. 1760. 

 Type — Alternatively Simple or Compound, uncorrected. 



The maker of this instrument devised numerous improvements in 

 the mechanism and optical arrangement of the Microscope, and the 

 present model is an important link in its development. For the first 

 time there is a slow and fine movement for focusing, by rack-and-pinion 

 and by screw, both applied to the stage, with the constant action of a 

 spring to check the motion. A small compass-joint at the top of the 

 pillar allows the carrying-ring to be turned one of the way when the 

 instrument is used as a simple Microscope. 



Presented to the Society March 21, 1900. See Journ. R.M.S., 1900 y 

 p. 269. 



