902 SEC. 18. BIOLOGY. 



The instrument stands on a massive brass tripod foot from the centre of 

 which rises a triangular bar of gun metal with a cradle joint at the lower end 

 in which is a tangent movement for the inclination of the instrument to any 

 required angle. The body is attached to the bar by an arm which moves on 

 its centre by a wheel and pinion, and is further capable of a backward and 

 forward motion. The arm can be turned on its centre over the stage for the 

 reception of single lenses, and the body is adapted for movement parallel 

 to the bar by means of a rack and pinion giving motion to a tube sliding 

 within another. The fine adjustment is effected by means of a fine rack and 

 pinion at the object glass end of the body. The stage is capable of movement 

 up and down the bar by means of a rack cut in the back of the latter and a 

 pinion. It is a traversing stage with two pair of dovetail plates at the back 

 at right angles to each other ; it is moved by two screws with divided heads 

 for the measurement of objects. The stage can also be made to rotate and 

 there is a divided head and vernier for reading small angles. The instrument 

 is provided with a mirror which is movable up and down the bar by a pinion, a 

 condenser and forceps on stands, stage condensers and forceps, animalcule cage, 

 and other ingenious apparatus. Quekett had probably not seen this instru- 

 ment of Benjamin Martin's when he asserted that James Smith was the first 

 in this country to make a microscope with traversing stage and quick and 

 slow motion in 1826. 



3525. Microscope used by P. Lyonet in his observations with 

 respect to the Cossus ligniperda. H. Ottmans, Amsterdam. 



These observations are described in his Treatise on the Anatomy of the 

 Caterpillar, 1760. 



3519a. Culpepper Microscope, made about 1790. 



E. Russell Sudden. 



A compound microscope of the form contrived by Mr. Culpepper. It consists 

 of a large external brass body, supported upon three scrolls fixed to the stage, 

 which is supported on three larger scrolls screwed to a brass pedestal. A con- 

 cave mirror is fitted to a socket in the centre of the pedestal. 



3529a. Large Amici Microscope, with apparatus complete, 

 by Chevalier. The Royal Microscopical Society. 



3529b. Double Microscope, by Culpepper. 



The Royal Microscopical Society. 



3529c. Single Microscope, by Dolland. 



The Royal Microscopical Society . 



3529d. Mechanical Finger, for picking up minute objects, 

 by Bailey, after Professor Smith's pattern. 



The Royal Microscopical Society. 



3529 e. Double Microscope, by Marshall. 



The Royal Microscopical Society. 



3529f. Single Microscope, by Tulley and Sons. 



The Royal Microscopical Society. 



3529g. Spectacles (4 pair), used by the late Robert Brown 

 in his botanical researches. The Royal Microscopical Society. 



