68 THE MICROSCOPE. 



as it appears when put together, and ready for use ; and 

 fig. 40 for packing in a small wood-case. The draw-tube 

 itself is the coarse adjustment ; whilst a finer is secured by 

 a well-made union-joint, into which the object-glass is 

 made to screw. With an additional arm for the reception 

 of a single lens, ifc may be converted into a dissecting 

 microscope. 



Mr. I, Newton Tomkins has constructed a very ingenious 

 and cheap moveable stage to his Warington microscope, by 

 simply having a small horse-shoe magnet let into a piece of 

 oak cut into the usual stage form, which he uses in the 

 place of the brass one. A drawing and description of the 

 contrivance is given in the Micros. Journal, July, 1857. 



M. Dujardin found that to reflect the rays of light truly 

 parallel, a prism of glass should be used in place of the 

 mirror. This prism, which is one of total reflection, must 

 be so arranged as to slide upon the end of the condenser, 

 and turn upon it in such a manner, that in whatever posi- 

 tion the lamp or light may be, the prism may be adjusted 

 to it. The quantity of light passing through it is less 

 than with the mirror ; and those test objects in which 

 delicate markings exist, are seen to much greater advan- 

 tage, in consequence of all the rays being reflected from 

 the same surface, which is not so with a silvered glass 

 mirror. 



Space will not permit us to enter into details respecting 

 the prices charged by the different manufacturers in 

 London and elsewhere. We can, therefore, only add that 

 the leading makers supply small instruments at from 10Z. 

 to 151. each, and that other manufacturers supply very 

 good instruments at from 51. to 10. each. The micro- 

 scopes made by Messrs. Smith and Beck, Mr. Matthews, 

 Mr. Pillischer, Mr. Ladd, Mr. Dancer, M. Nachet, &c., will 

 be found to meet all the requirements of the amateur or 

 student. Mr. Ladd substitutes a chain-movement for the 

 rack-and-pinion, in the construction of his instruments, 

 which, whilst it gives delicacy and smoothness, admits of 

 an exact adjustment being made by its means alone." 



