MOUNTING OBJECTS IN CANADA BALSAM. 227 



with a flat plate of metal, or a similar metal plate supported at 

 such a distance above the lamp flame (§ 121), as not to become 

 more heated than it would be through a water-bath. For hold- 

 ing the slide, either whilst it is being heated over the flame, or 

 whilst it is being subsequently cooled, the "Wooden Forceps 

 (Fig. 61) contrived for this purpose by Mr. Page, will be found 

 extremely convenient ; this, by its elasticity, affords a secure 

 grasp to a slide of any ordinary thickness, the wooden blades 

 being separated by pressure upon the brass studs ; and the lower 

 stud, with the bent piece of brass at the junction of the blades, 

 affords a level support to the forceps, which thus, while resting 

 upon the table, keeps the heated glass from contact with its sur- 

 face. Besides a pair of fine-pointed Metal forceps for holding 

 the object to be mounted, there should be another of a com- 

 moner kind for taking up the glass cover, the former being liable 

 to be soiled with balsam. A pair of stout needles mounted in 

 wooden handles (§ 105), will be found indispensable, both for 

 manipulating the object, and for breaking or removing air-bub- 

 bles ; and if these handles be cut to a flat surface at the other 

 extremity, they will serve also to press down the glass covers, 

 for which purpose a pointed stick also is useful. For holding 

 down these covers, whilst the balsam is cooling, if the elasticity 

 of the objects should tend to make them spring up, nothing is 

 more simple or convenient than a compressor made by a slight 

 alteration of the " American clothes peg," which is now in ge- 

 neral use in this country for a variety of purposes ; all that is 

 necessary being to rub down the opposed surfaces of the " clip" 

 with a flat file, so that they shall be parallel to each other when 

 an ordinary slide with its cover is interposed between them (Fig. 

 62). Great care should be taken to keep these implements free 

 from soils of balsam; since the 

 slides and glass covers are certain ^'°- ^2- 



to receive them. The readiest 

 mode of cleansing the needles 

 (their "temper" being a matter 

 of no consequence for these pur- 

 poses) is to heat them red hot 

 in the lamp, so as to burn off the spring Press. 



' balsam ; and then carefully to 

 wipe them. The forceps, both of wood and of metal, should be 

 cleansed with oil of turpentine or with rectified spirit. 



128. Much of the success of mounting objects in this mode 

 will depend upon their previous preparation. They should have 

 been previously well cleansed with water, from which they should 

 be transferred into proof-spirit, as this will dry out much more 

 readily than water. K they have any greasiness of surface or of 

 substance, this should be removed by maceration in ether or in 

 oil of turpentine ; and maceration in turpentine is also very use- 

 ful in preparing the way for the penetration of the balsam into 



