532 



these diagonals towards another antilepoint and we call this 2, from 

 this point we go again along a diagonal towards anollier anglepoint, 

 which we shall call 3 ; in the same way we go from point 3 

 towards point 4 and from this point towards point 5. (See the figs. 1, 

 3 and 5). We call this order of succession '"the diagonal succession". 

 It will appear from our further considerations for what reason this 

 definite order of succession has been chosen. 



Tjpe I. Now we shall deduce the P, 7-diai;rain when the five 

 phases form, as in fig. 1, the anglepoints of a convex (piintangie. 



As the lines 23 and 45 intersect one another, it follows for the 

 phases of curve (1) ; 



2+3^4+5 j 



(2) (3) 1(1) 1(4) (5)1 



We find for the phases of curve (2) : 



3 + 4;±l +5 ) 



(3j(4) I (2) I (l)(5)i 



Now we draw in a P, 7-diagram (fig. 2) arbitrarily the curves 

 (1) and (2);- for fixing the ideas we take (2) at the left of(l). With 

 regard to this the above mentioned reactions have been written at 

 once in such a way that also hei-ein curve (2) is situated at the left 

 of (1). [For the distinction of "at the right" and "at the left" of a 

 curve we have previously assumed that we find ourselves in the 

 invariant point on this curve facing the stable part]. 



(1) 



(2) 



Fig. 1 



Now we shall determine the position of curve (3). It is apparent 

 from the first reaction that the curves (2) and (3) are situated at 

 the same side of curve (1); as (2) is situated at the left of (Ij, (3) 

 must consetpiently be situated also at the left of (I). 



It is apparent from the second reaction that (3) and (1) are 

 situated on different sides of (2); as, according to our assumption 



