150 Laboratory Arts 



made by some simple geometrical method, perhaps the best 

 being that of opposite equal angles. Each division has again 

 to be divided into ten equal parts, and this may be performed 

 similarly upon a separate piece of paper, the scale so produced 

 being exactly cut out, and superposed upon each division of 

 the larger scale in turn, the subdivisions being pricked through 

 a simple matter if care be taken to get the ends absolutely 

 correct. 



The strip of paper used as above is to be divided into 

 tenths by a similar method, but it is best to transfer the whole 

 cubic centimetres to the burette first. This is done by one 

 of two methods. 



A. Cement the burette down to the bench with Chatterton's 

 compound, and take a pine rod about i metre long, pass 

 through it two stout darning-needles (see Fig. in, FF), ground 

 down to rather stumpy points, one near each end. The needles 

 should project about i cm. through the beam. Fix the paper 

 scale to the bench in line with the burette, so that the o mark 

 on the scale is immediately underneath one of the needle points 

 when the other is on the zero mark of the burette. With one 

 needle upon the o mark on the paper, scratch through the 

 wax with the other; move to the second mark and scratch 

 the waxed burette again, and so on until the whole burette is 

 marked. 



B. Place the burette upon a wooden platform with a 

 squared face (A), and cement in place as before. Cement 



FIG. 112. Straight-edge method of transferring graduations to glass tubes. 



the scale already made on the upper surface, and by means of 

 a steel straight-edge, pressed against A, as shown in Fig. 112, 

 the marks may be transferred to the burette. The exact manner 

 of doing this is to take a stout needle (a knitting-needle ground 

 to a chisel edge), place it at a point on the scale, move the 



