MOUNTING OBJECTS IN THE DRY WAT. 317 



page 276, for the reception of thin objects, by painting it on the 

 slide in the shape required. The object being placed within a 

 cell so formed, may be fixed down by making the edges of the 

 cover sufficiently hot in a spirit lamp to melt the cement 

 when it is laid upon it. Should this be ineffectually per- 

 formed, a small heated wire applied to the glass or to the 

 cement wUl readily accomplish it. If such a cell as this does 

 not look neat, the sKde may be covered with paper, with a 

 hole in it sufficiently small to hide all appearance of the 

 cement. Gutta percha or marine-glue, as described by Mr. 

 Shadbolt in page 290, rolled out into sheets, and cut out with 

 a knife or with punches of the required size, may also be 

 employed as a substitute for the paper, but it is difficult to 

 make the former stick to glass unless some solvent of it be 

 used as the cement. Even the small elastic bands made of 

 vulcanized India-rubber will answer for thicker objects, or the 

 glass rings or cells that have previously been described to 

 contain objects mounted in fluid, will do equally well for such 

 as require to be mounted dry. 



Mr. Darker's Method, — Objects, such as sections of wood, 

 that do not require a high power for their examination, may 

 be mounted in a very neat way after an excellent plan first 

 practised by Mr. Darker. The following description, abridgea 

 slightly from that given in a recent work, entitled Microscopic 

 Objects, will convey a good idea of the method to be adopted 

 for this purpose : — " Two slides of equal size being selected 

 the edges of each should be bevelled off on the metal plate 

 as represented by fig. 214, so that when they are put together 



Fig. 214. 



a groove or channel is formed, as shown at h In the figure. 

 The surfaces having been cleaned, the bevelled parts are to be 

 coated with a thin layer of sealing-wax varnish, when this is 

 dry, a label, if required, may be gummed to the bottom slide, 



