ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 



101 



MICROSCOPY. 



A. Instruments, Accessories, &c* 

 (1) Stands. 



Swift's Simple Dissecting Microscope.f — This is shown in fig. 1, 

 and consists of a metal base and sliding pillar for focussing, with 3-in. 

 and 2-in. lenses. 



Fig. 1. 



Swift's Newly Designed Microscope for Bacteriological Research.; 

 This stand (fig. 2) was constructed from suggestions given by Dele- 

 pine of Manchester. It is fitted with Swift's spiral rack-and-pinion 

 for coarse adjustment. The fitting carrying the optical tube has the 

 same wear-and-tear-preventing device as in the last instalment. The 

 fine adjustment is also the same as in the last instrument. The draw- 

 tube is divided to millimetres ; when fully extended it is 220 mm., when 

 closed 160 mm. The triple nose-piece is perfectly dust-tight. The 

 stage is covered with vulcanite, and is specially large to allow of the 

 free use of the largest size Petri dish ; its right-hand side is divided 

 into squares which answer the purpose of a finder. A full-size im- 

 proved Abbe condenser, fitted with iris diaphragm and special focussing 

 adjustment for raising or lowering it, is screwed to the under surface of 

 the stage. Flat and concave mirrors arc supplied, and a simple ingenious 

 device enables the manipulator to determine when they are in the 

 vertical axis. Three object-glasses are supplied with the instrument, 

 one of them being Swift's T V m - oil immersion N.A. 1'30. The 

 makers specially guarantee this particular lens to be of the highest 

 possible optical excellence. Another of the objectives is the ^-in., as 

 supplied with the last. 



* 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 



t J. Swift & Son's Catalogue, London, 1901, p. 26. 



X J. Swift & Son's special Catalogue, London. 



