194 H. J. ROrER ON A METHOD OF 



without in any way damaging the leaf or fungus ; now take a clean 

 covering glass, place it over the wax cell containing the object, and 

 press it firmly but gently down, then remove with the penknife all 

 superfluous wax close to the edges of the covering glass ; place over 

 this the covering paper, not applying too much moisture round the 

 central aperture, and the slide is complete, and can be labelled and 

 placed in the cabinet at once. 



It will sometimes happen that a slide is bored so deeply that it is 

 necessary for the convenient illumination of the object, that something 

 more than one thickness of wax should be placed in the cell, so as 

 to bring the object nearer to the covering glass ; this can be taken 

 advantage of to produce a very pretty effect. Before proceeding to 

 line the cell \vith the wax, place an ordinary wafer in the bottom of 

 it, moistening only the loiver surface, choosing one, say, of a deep 

 red colour; place over this a square of the white wax, which is always 

 semi-transparent, and the result will be a delicate pink ground, well 

 calculated to show up to advantage many opaque objects ; other 

 coloured wafers will produce at pleasure grounds of different tints, 

 quite destitute of " glare " or " reflection," and " soft " and pleas- 

 ing to the eye. 



The advantages of this method, which is not new, except in slight 

 but not unimportant ntodifications, are the unfailing certainty of the 

 process, its celerity, total independence of turntables and varnishes, 

 the lightness of the slides, the non-liability to breakage (for there is 

 nothing frangible but the covering glass), and last, but not least, the 

 permanence of the preparation. 



I see that an American professor is discarding a somewhat similar 

 method on account of, as he says, " the covering glass, sooner or later, 

 becoming covered inside with a dew-like deposit, which, when illu- 

 minated, will glisten like so many minute points of quicksilver." I 

 have myself noticed this occasionally in specimens mounted some- 

 thing in this style, on glass slides, but very rarely (not per- 

 haps one per cent.) when mounted on wooden ones ; and then no 

 doubt the wax was used when too new, sufficient time not having 

 been allowed for its volatile properties to evaporate ; it is probable, 

 too, that the wood itself may absorb the slight moisture which, in 

 the case of the glass, can obtain no other refuge than the covering 

 glass ; at any rate, speaking from one's own experience, I have 

 found no inconvenience on this score, after mounting many hundreds 

 of slides, extending over several years. 



