IO 



2/12 



IO 



Figure 2/11/1. 



2/12. Suppose next that a system of two variables gave the 

 line of behaviour shown in Table 2/12/1. The successive states 

 will be graphed, by the method, at positions B, C, and D (Figure 

 2/11/1). So the system's behaviour corresponds to a movement 

 of the representative point along the line in the phase-space. 



By comparing the Table and the Figure, certain exact corre- 

 spondences can be found. Every state of the system corresponds 



Table 2/12/1. 



uniquely to a point in the plane, and every point in the plane 

 (or in some portion of it) to some possible state of the system. 

 Further, every line of behaviour of the system corresponds 

 uniquely to a line in the plane. If the system has three variables, 

 the graph must be in three dimensions, but each state still corre- 

 sponds to a point, and each line of behaviour to a line in the 

 phase-space. If the number of variables exceeds three, this 

 method of graphing is no longer physically possible, but the 



21 c 



