October 7, 1921] 



SCIENCE 



335 



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2. In sucli a system the growth (negative 

 and positive) of a variable may be observed 

 by connecting the plotted points of each quad- 

 rant which satisfy their respective equation 

 with the points of each equation in the other 

 quadrants, thereby obtaining for each set of 

 three points a cycle line A, A^, A^ (as shown 

 in Fig. No. 2). These points not only repre- 

 sent the actual values of x, y, z, but their lo- 

 cation in reference to their respective axes 

 represents the quotients expressed by the 

 equations. 



For example, Point A would represent by 

 its location the quotient of certain values of a, 

 and 6; or A^ would represent by its location 

 the quotient of certain values of a and c, and 

 so on. 



The application of the method may be illus- 

 trated by an actual example. Suppose we have 

 the statistical data shown in the table given 

 below. These data may be advantageously an- 

 alyzed as outlined (Fig. 3). 



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