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III. — A New MieroscojpiG Slide. By M. Ernest Vanden Broeck. 



Communicated by Professor Eupert Jones, F.K.S. 



(Head before the Eoyal Microscopical Society, April 5, 1876.) 



Plate CXXXVIII. 



The great inconvenience with the ordinary slides is that in general 

 there is no possibility, -without breaking or squeezing the prepara- 

 tions, or at least damaging the label and glass cover, of adding to 

 the mounted specimens or altering the preparation at all. 



With the slides uncovered with glass there are the inconveniences 

 of dust and damage to the specimens. 



For good results the observer ought to be able to study the 

 preparation by both transmitted and reflected light, an 1 to be able 

 to apply the object-glass at ver;^ short distances. 



The following plan of preparing slides meets these difficulties. 



Seen from above (Fig. I.), the new slide does not differ from 

 ordinary slides ; but turned over (Fig. V.) it shows a different 

 principle of construction altogether. 



Figure II. represents a piece of cardboard, or thin wood, B, of 

 the size a, h, c, d, perforated in the middle. On the edges of this 

 opening (which may be either round or square) is gummed a glass 

 cover (Fig. I., I, m, n, 6), and over its edge is gummed a strip of 

 paper (red or blue). A, which is folded over below, Fig. II. Under- 

 neath the card B is gummed the card C, with its opening a, V, c, d', 

 Fig. II. Slips of ordinary microscopic glass are cut a little smaller 

 than the opening a, V, c', d' ; see Fig. III._, D. With a little brush 

 I then coat the glass slips with a thin layer of gum-arabic 

 mucilage mixed with a httle glycerine. Afterwards I cover the glass 

 D witli the paper D', which has an opening corresponding with 

 that of the glass cover. (The frame of paper D' is to prevent the 

 glass D sticking to the surface B when the glass slide is placed, 

 with its Foraminifera, or other objects fixed on D, in the cavity 

 a', h', c', d', of Fig. II.) Then I have little oblong frames of very 

 thin paper, gummed. Fig. IV., E, which are to fasten down the 

 glass D, and keep it in the cavity a, h', c, d', and exclude dust. 

 When finished, the slide has the appearance of Fig. I. above, and 

 Fig. V. on its under side ; and it can be used with either trans- 

 mitted or reflected light under different circumstances. For extra 

 large specimens, the perforated cardboard or wooden shps B may 

 be doubled. To rearrange or add to the specimens, wet with a 

 small brush the thin silver or tissue paper E, which is then readily 

 detached. With the nail, for which a notch is left at x in Fig. II., 

 the glass can then be lifted, and changes made in the preparation ; 



