216 THE AMERICAN MONTHLY [Aug., 



10.— A METAL TABLE.— FIGURES 11 AND 12. 



One needs a small table, of metal, to heat slides on. Get a 

 piece of heavy sheet iron 3x5 inches or of any other size you 

 wish. 



In each corner, make a hole at a point J inch from the sides 

 and ends. Outstrips ofthe same metal of which the table ismade 

 to be J inch wide and 4 or 5 inches long. Rivet one to each 

 corner ofthe table (Fig. 11). The figure (12) shows the man- 

 ner of riveting. 



11.— WASH-BOTTLES.— FIGURE 13. 



A wash-bottle is a convenience. Get a wide-mouth bottle, — 

 say a quinine bottle. Bore two quarter-inch holes in the cork. 

 Get a glass tube 4 inch in diameter, if you can. If not, one of 

 tin, iron, or brass will do, but glass is to be preferred because 

 more easily kept clean. Also, get two or three feet of 1 inch 

 rubber piping. By studying the illustration, it will be easily 

 understood (Fig. 13). Uj)on blowing at a, the air is forced in- 

 to the bottle, and it forces the water out at b, through the glass 

 tube, c. If the rubber tube a, be 2 or 3 feet long and the rubber 

 tube, b, the same length, it will be found of greater convenience 

 than bythe old way. The bottle can remain on the table. At b, 

 there should be a glass nozzle, d, like the pippets before des- 

 cribed. 



12.— CONDENSING LENS.— FIGURE 14. 



If you have a burning glass or a reading glass with a handle, 

 you can make a wooden stand that will answer every purpose. 

 Indeed, some prefer them in order to put the money into some- 

 thing that can not be made so easily. Your burning or reading 

 glass may not give as good results as a glass purposely made, 

 but good results can be obtained especially by lamp-light. We 

 will suppose your lens is as shown in Fig. 14. 



13.— CONDENSING-LENS STAND.— FIGURES 15—21, 23. 



Not all are expected to have nor can afford a complicated ar- 

 rangment. Some have a very large number of adjustments. 

 Some have as many as twelve motions or twelve adjustments 

 with moving the base. This is very convenient but is costly. 



For the base, take a block of hard wood such as oak, maple, 

 etc. Cut it 4 inches thick, 22 wide and 5 long. Cut a hole IJ 

 inches from one end and in the center (Fig. 21), make it either 



