GRAPHICAL ALGEBRA. 



91 



Hence it follows : 



The singular points in the field of the vector-sum are the points of intersection 

 of the curves 



T> 



(c) p-a = 32 and -j= 1 



On account of the ample information which the singular points give regarding 

 the field, it will be important to draw with as great care as possible these two curves. 

 In return much labor can be saved in other parts of the field, where few additional 

 data are required besides those involved in the knowledge of the situation of the 

 singular points. 



Tables M. Graphical addition of any vectors. 

 I. Table for drawing the field of the angle between the vector-sum and the vector-addend A . 



II. Table for drawing field of ratio of intensity of the vector-sum to that of the vector-addend A. 



159. Easily Accessible Data Regarding the Field of the Vector-Sum. Just as 

 we can find the singular points, we can easily find a series of further data regarding 

 the field of the vector-sum. It will save much labor to use these data as completely 

 as possible. 



