660 SUMMARY OF CURRENT RESEARCHES RELATING TO 



JAMES SMITH. 1841. 



Type — Compound : Achromatic. 



This stand was made in execution of an order given by the Council of 

 the Microscopical Society of London in August 1840, and has become a 

 model on which many English stands have since been made. A sub- 

 stantial pillar mounted on a solid tripod supports a grooved limb, which 

 itself carries directly the body, stage, and mirror. Coarse-adjustment is 

 effected by rack-and-pinion moving the body, whilst fine-adjustment for 

 the first time by lever and screw acts on the nose-piece only. The 

 mechanical stage has rectangular motion, and can be rotated. 



Described and figured in Microscopic Journal, ii. p. 1, and in Journ. 

 R.M.S., 1900, p. 553. 



ANDREW ROSS. 1842-3. 



Type — Compound : Achromatic. 



In execution of an order by the Council of the Microscopical Society 

 of London in 18-41, Andrew Ross produced this type of Microscope. 

 The pillar is mounted on a circular base, which rotates so as to increase 

 the steadiness of the base when the Microscope is inclined. The body 

 slides in the grooved limb, and the fine-adjustment acts by a lever on 

 the nose-piece. The mechanical stage has rectangular movements and 

 also rotates. The original instrument, made for the Society in 18-41, 

 was exchanged in 1863 for a Ross binocular instrument. The present 

 specimen was presented to the Society by Messrs. W. Watson and Sons 

 in 1899. 



Described and figured in Journ. R.M.S., 1899, p. 214. 



Dr. EDWIN QUEKETT'S Microscope. 1844. 

 Type — Compound : Achromatic. 



This instrument was designed and mainly constructed by Dr. Quekett, 

 the founder of the Royal Microscopical Society, and was bequeathed by 

 him to the Society. Whilst following James Smith's Microscope in 

 general arrangement, this model is characterised by greater rigidity of 

 the foot and, pillar. The mechanical stage is made on A. Ross' pattern. 

 Below the stage there is a focusing condenser, 



Bequeathed to the Society by Dr. Quekett, who died June 28, 1847. 



POWELL AND LEALAND. 1848. 



Type — Compound : Achromatic. 



This model is the first example in which the Microscope is hanging 

 in a tripod, and also the first example in which the fine-adjustment 

 moves the nose-piece by means of a lever within a bar. The mechanical 

 stage has Turrell's rectangular movement, and possesses a focusing con- 

 denser. This type of Microscope appears to have been first made in 

 1843, but as in all the features mentioned it is being reproduced at the 

 present day, it may be said to represent the modern instrument. 



Described in Journ. R.M.S., 1901, p. 727. A duplicate of this 

 instrument is described and figured in the Journ. R.M.S., 1898, p. 125. 



