THE SIMPLE MICROSCOPE 11 



hair brushes and some glass dipping tubes. The 

 latter are used for removing superfluous liquids, 

 washing dehcate tissues, and transferring tiny 

 organisms from the water in which they are stored 

 to the stage of the microscope. The glass tubes 

 supphed for filling stylographic and fountain pens 

 make good dippiog tubes, but for some work the 

 narrow apertures need to be enlarged. Dealers 

 supply tubes of various apertures, some straight and 

 others curved, for about 3d. each ; but I prefer to 

 prepare my own. The method is simple and re- 

 quires httle skill. Glass tubing as used by chemists 

 is to be bought cheaply enough ; it costs about Is. 2d. 

 per pound. Two or three permy worths in 12 or 

 14 inch lengths wiU be an ample supply. A piece, 

 say, 12 inches long is heated at the middle to a red 

 heat in a gas or spirit flame, and the ends drawn 

 apart gradually and carefuUy. The tube should be 

 twirled while in the flame. Naturally, when the 

 glass is softened by heat, and the ends of the tube 

 are pulled apart, the softened portion becomes 

 elongated and narrowed. When this is done and 

 the glass is cooled, a scratch with a fine file makes it 

 easy to break the tube evenly in the centre, and 

 two dipping tubes are now made. The rough edges 

 caused by the breakage are smoothed and rounded 

 by heating in the flame. Tubes may thus be 

 narrowed to any desired aperture, and they may 

 also be bent or curved as required. 



The filhng of a dipping tube is a simple matter. 

 Press a finger over the wide end so as to close it 

 effectually, plunge the other end in water, remove 

 the finger, and water will rush into the tube. Re- 



