916 SEC. 18. BIOLOGY. 



011 the glass-plate, and regulated by the upper lens in such a manner that the 

 lines can be seen plainly ; thereupon the picture is inserted, the microscope 

 being used as ocular. lu this manner the picture is sure to lie exactly on the 

 lower surface of the glass-plate ; consequently also on the prepared plate to 

 be inserted afterwards. By applying the illuminating apparatus the plane 

 mirror of the microscope should be used, the arrangement of which is easily 

 understood. The achromatic condenser, accompanying the apparatus, con- 

 sists of three achromatic lenses, and fits to microscope No. 3 (Xo. 35G2) 

 in the Exhibition. 



3592. Microscopic Apparatus. Series of the more im- 

 portant pieces of apparatus and object glasses now supplied for 

 use with the microscope. R. $ J. Heck. 



3593. Object Glasses (4), showing the lenses before they 

 are put into the cells. R. $ J. Beck. 



3593a. Hew Stand on the Continental Model, the 



diaphragm being provided with centering screws so that it can be 

 adjusted to each objective as applied. Henry Crouch. 



3593b. Microscope Objectives and accessory Appara- 

 tus. Henry Crouch. 



Suited to the stand described above, and for microscopic work generally, and 

 mounting apparatus and materials. 



3594. Object Glasses, Apparatus, and Accessories used 

 in the different branches of microscopical research. 



M. Pillischcr. 



3595. Microscope Lamp. M. Pillischer. 

 3542a. Microscope Lamp. James How <$ Co. 

 3512b. Tate's Air Pump. James How > Co. 



3 54:2 c. Selection of Transparent Photographs, for the 

 Lantern, illustrating lectures upon geology, consisting of sections 

 of strata, groups of fossils characteristic of the various sedimen- 

 tary formations, restorations of extinct animals, c. 



James How & Co. 



3595a. Fittings for Microscope. M. Lutz, Paris. 



3596. Apparatus to be used with the Microscope, for 



securing perfectly central illumination, manufactured by Wood 

 of Liverpool. Rev . W. H. Dallinger. 



The object of the apparatus is to secure minute and delicate alterations in the 

 position of the flame-image upon the mirror or prism, since it lias been found 

 by the exhibitor that perfectly central illumination can only be secured by 

 having the image of the flame exactly under the optical axis of the sub-stage 

 combination, after the latter has been made to coincide with the optical axis 

 of the object glass. This will enable the microscopist to illuminate the whole 

 field of a' -mch object glass through an aperture of yijjth of an inch iu 



