82 MOUNTING TRANSPARENT ROCK-SECTIONS. 



conclude that the water " molecules " are too large to find their 

 way through these spaces, and that they are laboriously "working 

 their passage " underneath the specimen. Do not try to 

 hasten the process by '^nudging" the specimen with the edge 

 of the knife-blade ; this will only end in a vexatious smash. You 

 7nusf wait. After all, on an average, about a dozen specimens 

 can be " steamed " from the wood and mounted in balsam, in 

 about two hours. With every care, a specimen will sometimes 

 break in two or more pieces, but you must just take advantage of 

 this " multiplication by division," and make a slide of each 

 fragment. The specimen having at last become loose on the 

 wood, you must heat a glass slide over an argand burner. Take a 

 pen-knife, and with the blade, move the specimen ge/z^/y to the edge 

 of the wood. Put the knife-blade under the edge that projects 

 beyond the wood; steady your hand on the side of the wood, do not 

 attempt to lift the section, but draw it off the wood gently ; the 

 water from the condensed steam will keep it attached to the knife. 

 Put a drop or two of warm balsam on the heated slide. Have 

 ready a slide template covered with paper, having a circular hole 

 cut in the middle of it, five-eighths of an inch in diameter, or the 



same size as the specimen, as shown 

 in Fig. 4. Put the template under 

 the heated slide, holding both in the 

 left hand. 



Dry the free side of the specimen 

 (still on the knife) over the argand 

 lamp. Place the specimen gently on the balsam, directly over 

 the hole in the template. Draw the knife off sideivays. If you 

 attempt to lift it up, the specimen will break in pieces, the 

 water holds the section so firmly to the knife. Heat a three- 

 quarter inch glass cover over the argand lamp, and put two 

 drops of balsam on it. Lay it gently on the specimen, which 

 by this time should be perfectly flat. Do not squeeze ; heat the 

 template, slide, and section over the lamp, and let the balsam 

 gently boil, to expel the air-bubbles. Again, do not squeeze, 

 but keep the object in position over the template with the point 

 of the knife-blade. Allow the slide to cool a little. Now gently 

 squeeze down the glass slip so as to expel all superfluous balsam. 



