718 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Gary's Microscope.* — With regard to this portable Microscope, pre- 

 sented to the Society by Mr. F. Gleado\v,f the reference there alluded to 

 uas Deen found by Mr. Parsons in a small book in the Society's Library 

 on " C. Gould's improved pocket compound Microscope," published by 

 Gary, 181 Strand, 1828. 



A Naturalist's Telescope. — A telescope capable of focussing objects 

 only a few feet distant has been introduced by Mr. Baker for naturalists 

 and others who require to watch birds, insects, or other animals, and is 



represented in fig. 189. It is a portable instrument measuring 15^ in. 



extended and 6 in. when closed; it is fitted with a sling with leather 



f 



caps. It has an object-glass of 1 • 2 in. aperture, working at - , and its 



8 



power is 15. 



Old Microscopes.^ — A collection of twelve old Microscopes has been 

 presented to the New York Botanical Garden Laboratory by Mr. Charles 

 F. Cox. Among these are three Culpepers, a John Cuff, a Wilson's 

 " screwbarrel " by G. Adams, an Ellis' aquatic, a Jones' improved com- 

 pound, a Chevallier, and a Cary's portable. 



(2) Eye-pieces and Objectives. 



The Society's Standard Eye-pieces. — The firm of C. Baker, High 

 Holborn, announce,. in their Catalogue for 1900, 1901, their adoption of 

 the Society's Standard Eye-pieces. 



(3) Illuminating: and other Apparatus. 



Swift's Substage Condensers. — Figs. 190-192 represent the new 

 substage condensers manufactured by Messrs. Swift. Fig. 190 is the 

 pan-aplanatic condenser with a N.A. of 1 • 0, back combination clear 

 diameter 0*55, and an aplanatic cone of 0*92. It is a very perfectly 

 corrected combination, and as carefully made as an objective. Fig. 191 

 is Messrs. Swift's latest form of pan-aplanatic oil-immersion condenser ; 

 it has a N.A. of 1'40, and an apla'natic cone of fully 1*30 ; the back 

 combination has a diameter of 0*65. Fig. 192 represents Swift's apo- 

 chromatic dry condenser. The combination is made throughout with 



* Cf. this Journal, 1898, fig. 82, p. 474. f Cf. this Journal, 1899, p. 673. 



X Journ. New York Hot. Garden, i. (1900) pp. G8-70. 



