2. Continuous Distribution of Elements 
By a continuous distribution of elements, it is meant that 
the elements are in a region of space where they are every- 
where contiguous and dense. 
(a) Array in the Plane (fig. 2) 
Z SOURCE 
P(xo ’ Yo AO) ) 
W(x, y) 
a B ELEMENT (x, y) 
Figure 2. Source and a typical element of a plane array. 
Let the array consist of the points of the boundary and the 
interior of a region 8B. Let B be a connected and a compact 
set. Let (AA porte AA.) be a partition of B such that the 
responses on AA; are approximately equal. Then the 
response on AA, is approximately 
