TEXT BOOK OF LANDSCAPE GARDENING 
point mounted on another bar. The ratio of this relation may be 
varied by adjusting the bars, the pencil and the tracer point to 
various positions. When the tracer is drawn along the lines of a 
plan the pencil will reproduce the plan at a pro- 
portionately larger or smaller scale. When the 
pencil describes the larger motion the new plan 
will be an enlargement but if the pencil and 
tracer are transposed in position so that the 
pencil describes the lesser motion the new plan 
will be a reduction. This method is simply a 
mechanical application of the radial method, the 
fixed end of the pantograph bars corresponding 
to the central point used in that method. 
Proportional Dividers 
i I This is a mechanical device having two legs 
i i which cross at a movable pivot and open pro- 
iW portionally on opposite sides of it; this propor- 
| tion may be varied by moving the pivot back or 
forth along the legs of the instrument. When 
adjusted so as to give the desired ratio the pivot 
is clamped in place and measurements taken off 
the original plan with one end of the instrument 
are plotted on the new plan with the other end. 
This is not so much a separate method of enlarge- 
ment or reduction as it is an instrument which 
may be made use of in any other method. This method is one of 
the most practicable of all. 
Fig. 11. ProportionaL 
DIvERs 
Equipment 
For practice in reducing and enlarging the pupil should have 
several maps and plans of various sizes available. He must have 
an engineer’s scale, with the necessary drawing board, T-square, 
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