ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 609 



Jackson (see this Journal, 1002, p. 721), and is an interesting type, 

 being the forerunner of the well-known Jackson-Lister model. The 

 foot is of the flat horse-shoe form, carrying two turned brass pillars, 

 to which the limb is attached by means of a cross-bar working through 

 centres at the top of the pillars. The limb is grooved its entire length, 

 and has V-shaped fittings in which the body, mechanical stage and 

 substage work. One side of the V fitting is screwed on to the limb, so 

 that any wear can be compensated for. 



The rack-and-pinion movements to body and substage are actuated 

 by milled beads placed behind the limb. 



The mechanical stage has rack-and-pinion movement in both direc- 

 tions, and is also provided with a micrometer screw and lever fiue- 

 adjustment. The substage sliding-piece also carries the mirror, which 

 is a plane one only, mounted in gimbals. 



The substage condenser, which consists of a Huyghenian eye-piece 

 with wheel of diaphragms placed between the lenses, has a tinted glass 

 cap for modifying the illumination ; the lenses also are so arranged that 

 either can be easily removed when not required. 



The body of the Microscope is of large size, and is provided with a 

 draw-tube. 



The mahogany box into which the instrument packs also contains 

 the following apparatus : — 3 eye-pieces, one of which is provided with a 

 Jackson screw micrometer ; l|-inch objective, by Jas. Smith, with 

 lieberkuhn ; y%-inch objective by Jas. Smith, with lieberkuhn, and 

 correction collar ; |-inch objective by Smith and Beck, 6 Coleman 

 Street ; stand condenser, stage forceps, tweezers, box of dipping-tubes, 

 live-box, dark-well and carrier, and stage micrometer. 



A New Microscope and its Applications to Stereoscopic Photo- 

 micrography, by A. Quidor and A. Nachet.* — ^This instrument (fig. 88) 

 satisfies with a single apparatus all the requirements of the laboratory — 

 minute dissections, histology, cytology, photomicrography, photographic 

 enlargements, or diminutions. Its main purpose, however, is to obtain 

 the stereoscopic presentation of objects examined or dissected. Two 

 cases may be distinguished according to the size of the objects : — 



1. When the object can be examined only by a Microscope. 



2. When the object can be examined either with a loup, or without 

 a loup. 



(1) The general arrangement of the Microscope resembles that of 

 ordinary instruments. But, whilst the object-stage remains horizontal, 

 the over-stage M with the objective is jointed at C, and is inclinable 

 to the right and the left of the plane of symmetry, the amount of 

 inclination being measured by the index E. Moreover, a rod bearing a 

 photographic camera with a frame for receiving slides of ordinary 

 stereoscopic form can be placed instantaneously above the Microscope, 

 the camera being connected on by a double tube T, which effectually 

 shuts out all exterior light. The Microscope is now inclined at an 

 angle a to obtain on the side B of the sensitive plate a first photo- 

 graph of an object in the focus of the objective 0, situated at the apex 



* Original communication. See also Comptes Rendus, cxliv. (1907) pp. 908-10 

 (1 fig-)- 



