260 THE A-MKliUAN .MONTHLY [Sopt., 



the staiio. It will apjioar quite struoturt'lcss at first. In two or 

 tlirt't' luinutt'S tlir tliickriu'd boriU-r will look orinkU'd ami in a 

 few luinutes small spocks of color will commence, each centre 

 gn\{lually sprcadinu with llowor-likc crystals, until they meet 

 one ani»thcr, when they should he (juiekly mounted in pure 

 Canada halsam. 



As it is advisahlo to mount them as soon as possihle after you 

 have arrived at the state you wish to ])reserve, the <:lass cover 

 should he cleaned in readiness, while the slide is hcing heated 

 on the hot-jilatc. 



The simplest and most <'fl'ectual way of c'leaniuL' the covers is 

 hy making two round cork jiads, which sliould he quite Hat and 

 ahout li across at the Ixick; with a short handle, like a stumpy 

 rubber stamp; the face should be covered with clean chamois 

 leather, pulled tijrht and tied around the pad with thread. Take 

 a clean cover out of the box with a small pair of tweezers, plact; 

 it on t)ne of the pads, and rul) it well with the other pad turn- 

 ing itover once or twice, when it will i)ecome clean. You can leave 

 it between the i)ads till you are reaily to use it which will keep 

 it free from dust. 



To mount the i)rej)aration in ])ure Canada balsam; the clean- 

 est and safest Avay of using it is to have it in a collajtsiblc tube, 

 the tube should be placed on tlie liot-plate to liquefy the balsam 

 but not be made too hot so as to raise air bubbles. Warm the 

 slide on the hot plate and droj) as much Canada balsam on the 

 slide as will fill the circle of the glass cover when pressed down. 

 Should there be any airbubldes, warm the point of a needle and 

 touch them when they will disappear. If the needle point is red 

 hot the large bubbles will break but there will l)e a quantity of 

 small ones formed very diflicult to get rid of. Take the slide off 

 the hot jjlate and place it on the card-board guide being care- 

 ful to ])lace the ])rei»aration with the thick edge away from you, 

 so that when you jtut the cover glass down on the balsam, 

 should there be any air bubljh s tliey will readily escape at the 

 thin edge, while the}' would be imprisoned if the slide were turned 

 the other way. Then take the cover glass out of the pads with 

 tweezers and jmt it slanting to touch the balsam from the out- 

 side edge, letting it droj) onto the slide and i)re.ss it down to 

 spread the balsam so as to fill the circle and guide it as nearly 

 central as you can. Then put a small Ijrass clip t«i bold it se 



