122 APPENDIX. 



ever, frequently disperse of themselves as the balsam dries. 

 The thin glass cover, being warmed, should now be placed 

 upon the object, and a slight pressure applied to get rid of 

 the superfluous balsam. Place the slide in some warm spot 

 to dry ; an oven will do very well, if the fire has been some 

 time removed and there is not sufficient heat to make the 

 balsam boil. 



In a short time the balsam round the edges of the cover 

 will be hard enough to admit of the greater part being 

 scraped off with a knife ; the remainder may be got rid of 

 by wiping the slide with a rag dipped in turpentine or ether. 

 The finishing touch consists in labelling the object with its 

 proper name. It will be found advantageous to place the 

 common name of the specimen at one end of the slide, and 

 its scientific name at the other. 



Some persons prefer covering their slides with ornamental 

 paper, which may be obtained of almost any optician. 

 Others prefer the glass without any covering at all. In the 

 latter case the edges of the slide should be ground, the 

 round thin glass covers used, and the name scratched upon 

 the slide with a writing diamond. In the former, the edges 

 of the slide, being covered with paper, need not be ground, 

 but square thin covers should be used instead of round ones, 

 and the name written with pen and ink in the square places 

 allotted at each end of the slide. 



LEGS OF INSECTS (plate 7, figures 205, 206, 207 ; plate 8, 

 figures 215 to 219, 223, 224. These require a little more 

 preparation than wings ; and as they possess some thick- 

 ness, and are mostly opaque, besides being of a hard, horny 

 character, they should be placed for a fortnight, or even 

 longer, in liquor potasses; this will soften the tissue and 

 dissolve the muscles and other matter contained within 

 them, so that by gently pressing the limb between two 

 slips of glass, the interior substance will gradually escape, 

 and may be removed by repeated washings. The squeezing 

 process, however, must be conducted gently, to prevent 

 any rupture : perhaps the best plan is to plunge the slips 

 of glass into a basin of clean water, when all impurities 

 oozing out from the pressure will sink to the bottom. 

 Should the leg not be sufficiently softened to be squeezed 

 quite flat, it must be again placed in the solution for 

 a longer period, until this result be obtained. On re- 

 moving it from the potash, it should be well washed with 

 a camel-hair pencil in clean water, placed between two slips, 

 held together by an American clothes-peg with a good stiff 



