136 MEMORANDA. 



plialtum dissolved in Benzine or Benzole instead of turpentine, 

 because it dries so quickly that a great many more objects 

 can be mounted and finished in a day with it than with any- 

 other cement. 1 finish it off with a coat of asphalt in tur- 

 pentine, to give it a smooth appearance. 



It should be kept, like all cements for the mounting of 

 microscopic objects, in a capped bottle, so that the brush is 

 always soft and ready for use. 



Benzole is also the most convenient solvent for removing 

 superfluous balsam from the outside of the glass covers under 

 which objects are mounted in that medium. — J. W. Law- 

 raxce, Peterborough.* 



Registration of Objects. — I beg to subjoin notice of a simple 

 mode of registering objects on slides, which was devised by 

 me in India, and has answered all ordinary purposes so effici- 

 ently as to induce me to hope it may prove useful to micro- 

 scopists. 



It possesses three great advantages, — in requiring no sepa- 

 rate apparatus, no special adjustment of slides or stage, and 

 costing nothing. It is adapted for use with all the higher 

 powers of the microscope. Although more readily available 

 where the body of the instrument admits of lateral displace- 

 ment, it may nevertheless be used where no such arrange- 

 ment exists, by simply elevating the body to a sufficient 

 height to allow of the bearings of the spot of light given off 

 from the illuminator being accurately taken by the eye and 

 hand. 



Suppose an object to be in the centre of the field of vision. 

 The body of the microscope is either turned aside or raised, 

 as the case may be. The slide being securely clamped in 

 position, two minute marks are made, with a writing diamond, 

 perpendicularly above, and in a line horizontal with, the spot 

 of light thrown upon the object by the condenser. The 

 smaller the spot of light, of course, the more easy will it be 

 to denote the situation of an object accurately. The slide is 

 now removed, and the scratches are converted into short 

 vertical and horizontal lines, varying in length according to 

 convenience. These two lines are now joined together by a 

 third line; and, lastly, a number is attached, at either angle 

 thus formed, for entry in the note-book or catalogue of the 

 observer. 



To find the object again, all that lias to lie dune is to place 

 the slide on the stage, and the body of the microscope being 



* The addition of a littlegold size to the solution of asphalt uni in bei./.iuc 

 will be found useful in rendering it less brittle. — [Eds.] 



