ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 713 



MICROSCOPY. 



A. Instruments, Accessories, &c* 

 fl) Stands. 



Old Portable Microscope by Dollond. — Major F. R. W. Sampson 

 has kindly presented to the Society this instrument (fig. 76). The 

 Society has not hitherto possessed one of this form, and it is therefore 

 a very desirable acquisition, more especially as it bears the maker's name. 



It seems to be an adaptation of Cuff's New Constructed Double 

 Microscope, the body, stage, and some other details and the acces- 

 sories, being similar to those of Cuff's instrument, but the pillar, instead 

 of being fixed, is hinged to a bracket secured to the inside of the bottom 

 of the case. The Microscope always remains in the case, which serves as 

 a base for it. When packed the instrument lies horizontally in its box, 

 but it can be set at any position from the horizontal to the vertical. 

 One end of the box is hinged so as to let down and allow the mirror to 

 project beyond when the body is elevated. To economise space in 

 packing, the body is removed from the socket of the arm, and the stage 

 is racked down low enough to allow of the lower part of the body being 

 passed through the stage. The latter is then racked up until the eye- 

 piece enters the socket of the arm from below : the body is thus securely 

 held in place. 



The pillar is square, and, as already mentioned, hinged at its lower 

 end. The stage is attached to a sliding bracket, and is focused by 

 rack-and-pinion. There are two springs under the stage for holding 

 a small tube for observing objects in water. The tube is held in a 

 diagonal position to prevent the water running out, and it also permits 

 any air to escape and not remain to obstruct the vision as it would do 

 if the tube were corked and used in a horizontal position. The mirror 

 is concave, and can be moved up and down on the pillar. The body 

 slides into a socket at the end of a short arm that is secured to the top 

 of the pillar. The part of the body standing above the arm forms the 

 eye-piece, the eye-lens of which is compound, consisting of two lenses, 

 the upper one being plano-convex and the other bi-convex. The field- 

 lens is also bi-convex. There is a micrometer scale ruled in squares, 

 forty to the inch, screwed into the eye-piece just below the diaphragm. 



Originally there were six powers — simple lenses — but No. 1, the 

 highest power, is missing. The remaining apparatus consists of the 

 usual spring-holder for " sliders," a cone for cutting off extraneous light 

 from the mirror, a lieberkuhn and fitting that slides on the lower part 

 of the body, bull's-eye and arm, stage forceps, etc. There are also two 



* This subdivision contains (1) Stands ; (2) Eye-pieces and Objectives ; (3) 

 Illuminating and other Apparatus ; (4) Photomicrography ; (5) Microscopical 

 Optics and Manipulation ; (6) Miscellaneous. 



