Graphic Methods for Presenting Facts
In the preceding illustrations of this chapter there has been such similarity in the shape of the curves considered that they were superimposed for comparison. Here the curves are of different shape and they are shown in separate fields so that the contrast may be more striking. The chart at the left should have had the zero line shown. It is dangerous to base conclusions on the comparison of two curves unless the zero lines are shown in each case
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Fig. 109. Comparison of Different Kinds of Steel Containing 0.2 per cent Carbon, as shown by Tensile Tests on Specimens 100 mm. long and 13.8 mm. diameter. The Vertical Scale Represents Thousands of Poxmds per Square Inch and also Percentage of Contraction or Elongation
The heavy line shows ultimate strength