ARCHDEACON PRATT ON THE ATTRACTION OF THE 
fig. 5 I have laid down the Enclosed Space on a scale, and, for convenience of 
reference, drawn parallel lines over the whole of the Doubtful Region, marking the 
elevations of the various parts according to the assumed law. 
Fig. 5. 
39. The width of the lunes by which the enclosed space is to be traversed I shall 
make 30°, as this will lead to no material error by making the compartments too wide 
to obtain a fair average of their height (see art. 16.). In a closer approximation, 
however, it would be desirable to make the lunes more numerous and narrower. At 
each of the stations A, B, C, I shall make the middle line of one lune coincide with 
the meridian. On the right and left limits of the Enclosed Space there will be lunes 
of a less width than 30°. In short, the lunes will be as follows : — 
At A, lune I., width (3=24°, azimuth of middle line =27° west. 
At A, lune 11., width (3=30°, azimuth of middle line = 0°. 
At A, lune III., width (3=30°, azimuth of middle line =30° east. 
At A, lune IV., width (3=30°, azimuth of middle line =60° east. 
At A, lune V., width (3=20°, azimuth of middle line =85° east. 
