IQ4 APPENDIX II. 



For example, when the slide has been moved 34-2 parts 

 from the centre of the cylinder, the dividing plate is to be set 

 successively to 10, 80, 190, 260, and a hole is to be drilled in 

 at each of these positions. The slide rest is then to be moved 

 on to 50 parts, and holes are to be drilled in at 15, 75, 195, 

 255. Steel wires, each about 0^3 long, are to be forced into 

 the holes thus made, and half the surface is formed. The 

 remaining half can be similarly constructed : a length of o?c>66 

 cos 2/ is to be coloured upon each wire to show the pitch. The 

 sign of the pitch is indicated by using one colour for positive, 

 and another colour for negative pitches. 



THE END. 



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