CH. XI] MODELS FROM SERIAL SECTIONS 421 



One should take the precaution to number each drawing as 

 it is made; then confusion in the later processes will be 

 avoided. 



683. Cutting out the sheets for the model. "With the blotting 

 paper, if the drawings are small the cutting is easily done with scissors 

 or a knife. When the drawings are large and especially when the 

 model is to be made by representing each section by two or more 

 thicknesses of blotting paper, it has been found that an ordinary 

 sewing machine can be used to do the cutting. By setting the regu- 

 lator for the shortest stitch, an almost continuous cut is made and 

 the parts are easily separated. If a large sewing-machine needle is 

 sharpened in the form of a chisel, the cut becomes considerably 

 smoother. It has been found advantageous when long continued or 

 heavy work is to be done to attach to the machine an electric sewing- 

 machine motor. Skill in guiding the work is soon acquired. There 

 are some details of a complicated drawing which are more easily cut 

 by the scissors or a knife after the main lines have been cut by the 

 machine." 



684. Contrasting colors for marking groups of sections. "It is 

 a great advantage in any working model to have sections at regular 

 intervals in marked contrast with the body of the material. Blot- 

 ting paper of a large variety of colors (black, red, blue, pink) is easily 

 obtained in the market. In the models made every tenth plate was 

 a bright or light color and every one-hundredth was black, rendering 

 rapid numeration easy." 



685. Putting the sheets together to make the model. - "When 

 the paper sections are thus prepared they are piled and repiled as is 

 usual until the shape conforms to an outline predetermined from 

 photographs, drawings, or measurements made before the specimen 

 was cut." 



"It has been found that an easily prepared support and guide for 

 the model in process of setting up is made by cutting the outline 

 to be followed from a block of four or five sheets of blotting paper, 

 marking upon it the lines of direction of every tenth or twentieth 

 section. The colored numerating plates must of course conform to 

 the spacing and direction of these lines." 



