25 



To facilitate the free-hand use of the aplanatic lenses, Nos. 5 10, we also 

 supply a convenient handle with a ring, No. 19, for inserting the lenses (Fig. 8). 



Price of Handle with ring: Marks 3. . Code-word: Pane. 



Tripod Stands, No. 20, are only supplied for use with the improved aplanatic 

 lenses, Nos. 9 and 10. 



Price of Tripod Stand: Marks j. . Code-word: Panoso. 



In addition to the lenses already specified we keep an assortment of others 

 of simpler construction, viz: the so-called Doublets, Nos. 13 and 14, magnifi- 

 cation 15 X and 30 X; ar >d the so-called WlLSON Magnifiers, Nos. 15 and 16, 

 consisting of two lenses in brass mounts, which give magnifications of 5 or 

 10 diameters according as the lower lens is used singly or both are used in 

 combination. 



These last-mentioned simplified lenses are specially adapted for our Dissecting 

 Stands P V or for free-hand use. 



A handy Pocket-magnifier, No. 17, consists of two achromatic lenses and 

 is made in the form of a folding lens with ivory mounts. The single lenses 

 yield magnifications of X 3 and X 5 respectively, the two lenses combined that 

 of 8 diameters. 



For the rapid examination, under high magnification, of specimens of algae 

 or similar objects we supply an Algascope, No. 18, with magnification of 

 120 diameters. It consists of a simple hemispherical lens in metal mount, with 

 glass plate for supporting the object and a focusing screw. 



For particulars of the improved Algascope refer to /. 23. 



When subsequently ordering lenses which are intended for 

 use with dissecting stands or lens holders, particulars of the latter 

 should he given to enable us to provide the necessary holders and 

 adapters. 



All lenses, except folding lenses, are supplied in wooden cases with in- 

 scription. 



