of incidence for one, two, & c. reflexions, B being - the point of 90°, and C that of 
0 of incidence. The point D or the line A D is the point or line of maximum 
polarization, viz. 7-3° for silver; and the figures 1, 2, 3, 4, 5, &c. show the points 
or nodes, and their distances from C, the angles of restoration. The loops or 
double curves lying between the points 1,2,3, arc drawn to give an idea of the 
intensity of the elliptic polarization, which has its minimum at 1 , 2, 3, &.c. and its 
318 I>R. RREWSTER ON TIIE PHENOMENA AND LAWS 
By setting out therefore from these points, and attending to the alternation of 
the signs, it is easy to determine for any number of reflexions its proper signs, 
whether it is a multiple of an integer or of a mixed number. 
In order to illustrate this Table, I have here projected some of its results as 
far as six reflexions. The concentric arches 1 1, II II, &c. represent the quadrant 
c 
