MAKING SECTIONS 59 



Very large objects are often embedded with the aid of two thick L-shaped 

 pieces of metal which, when fitted together, form a rectangular mold of vary- 

 ing dimensions. The author regards these as very clumsy and would always 

 prefer to prepare a cardboard or paper box than to endeavor to maneuver 

 metal molds which are always getting jarred out of place at the wrong moment. 

 The preparation of a paper or cardboard box is easy; the method preferred by 

 the author is shown in Figs. 22-27. 



A rectangular sheet of thin cardboard or stout paper approximately twice 

 as long as it is wide is needed. The area of the floor of the box will be about 

 one third that of the sheet taken, but a little experience will soon show what 

 size sheet to select for the box required. The sheet is laid on a flat surface, 

 and the long sides are folded inward (Fig. 22) until they almost meet in the 

 middle. These folds are well creased with the thumb nail. The sheet of paper 

 is flattened again, and the other two edges (Fig. 23) are folded in the same 

 manner. It is necessary, however, that these folds be much larger than the 

 first folds made. These folds are also well creased with the thumb nail. Then 

 the folded sheet is laid out (Fig. 24), and the corners are folded in the man- 

 ner shown. Since these end folds are larger than the side folds, there will be 

 an overhanging flap of paper at the top. After all four corners have been 

 folded in this overhanging flap (Fig. 25), the flap is folded back over the trian- 

 gularly folded corner sections, and this crease particularly firmly pressed with 

 the thumb nail. When this has been done at each end, the box is finished and 

 may be opened out as shown in Fig. 26. It will be found that the corners are 

 not square, but may be squared by pressing with the thumb and forefinger in 

 the manner shown. The finished box is shown in Fig. 27. This box is a great 

 deal larger than that usually employed but has been selected for ease of illus- 

 tration. Some people prefer to cast themselves a series of rectangular boxes 

 from plaster of Paris. This can be done by any competent craftsman but will 

 not be described. 



After the box has been prepared, the actual process of embedding is begun. 

 This is shown in great detail in Figs. 28-31. Before starting, it is necessary 

 to make sure that one has available the following items: (1) A dish of water 

 of sufficient size that the finished block may be immersed in it readily; in the 

 illustration an ordinary laboratory finger bowl is in use, (2) some form of heat, 

 an alcohol lamp being just as effective as a bunsen burner, (3) a large slab of 

 plate glass, and (4) a wide-mouthed, eye-dropper type pipette. The oven em- 

 ployed should contain the object itself in a small container of molten wax, as 

 well as another container of the medium used. It must be emphasized that one 

 cannot impregnate an object with one kind of wax and embed it in another. 



