LABORATORY MANIPULATION 



21 



The student should take an inventory of his apparatus 

 as soon as assigned a place in the laboratory. In case 

 any of the pieces are broken or missing, the attention of 

 the instructor should be called to them. Always, at the 

 close of each day's work, the apparatus should be 

 cleaned, placed in the desk, and the desk locked. The 

 apparatus and desk should always be kept in a neat and 

 orderly condition. Untidiness is a frequent cause of 

 failure in laboratory work ; neatness and careful atten- 

 tion to details are necessary to success. 



24. Cutting Glass Tubing. Lay the glass tube on the 

 top of the desk or any flat surface. Draw a sharp three- 

 cornered file across it two or three times, always on the 

 same place at which it is to be broken, until a scratch is 

 made through the annealed surface of the tubing. Take 



Fig. i. Breaking glass tubing. 



the tube in the hands with fingers and a thumb on each 

 side of the scratch (see Fig. i). The scratch should be 

 nearly between and on the side opposite the thumbs. 

 Pull the hands toward the body as if bending the tube, 



