44 



IX. — On a method of mounting objects in Canada Balsam. By 

 Thomas Boys, Esq. Communicated by J. S. Bowerbank, Esq. 



(Read May 21, 1845). 



Having had some experience in laying down objects in balsam for 

 the microscope, and finding that I succeed uniformly without air- 

 bubbles, I have adopted your suggestion, of giving a short detail 

 of the method I pursue, in the hope it may be acceptable to persons 

 who may perhaps be induced to make the experiment, and so improve 

 upon my plan. 



The first thing to be considered is the simple apparatus required. 



1. A small single-wick oil lamp, having a glass chimney about four 

 inches long. The flame to be about the size of that used in a 

 small hand-lantern. 



2. Slips of glass of required size, and small pieces of thin glass to 



cover the object ; — all well cleaned. 



3. A pair of nippers, to hold the slips of glass. 



4. A pointed iron piercer, in a wooden handle. 



5. A bottle, containing the clearest Canada balsam, diluted with the 

 best spirits of turpentine, to a consistency to allow it to drop 

 readily from the end of the iron piercer. 



The preceding articles being spread before you, ready for use, and 

 the object to be displayed being well examined for choice of position, 

 and cleansed if necessary, fix the slip of glass in the nippers ; dip 

 the end of the piercer about half-an-inch into the balsam, when (after 

 losing a large portion before it can be withdrawn) there will remain a 

 full drop to place upon the slide where required. The centre of the 

 slide should now be rested across the chimney of the lamp, until the 

 balsam begins to spread, when it should be immediately withdrawn. 

 The object is now to be placed upon this drop of balsam ; the piercer 

 is again to be dipped into the bottle, and another drop (a single drop 

 is generally sufficient) of balsam is to be withdrawn, and to be let 

 fall upon the object so as to well cover it. In this state the slide may 

 be suffered to remain (covered, in order to keep away dust) for two or 

 three minutes or more, so as to give the balsam time to penetrate ; 

 the thin glass is then to be taken up between the thumb and fore- 

 finger, and gently placed, as nearly horizontal as possible, upon the 



