1887.] Mr A. C. Elliott on Formula for Retaining Wall. 95 
(3 = 0. 
h Y = 3-75. 
fj e = 101 lbs. per cub. foot. [Mr Baker.] 
4 
p m — 46 x = 49 lbs. per cub. foot. [Mr Baker.] 
O' i o 
there is found 
*=•386 6 = 1-448 ft. 
lu 
But actually the wall was only 1 foot thick; whereas, as has just 
appeared, according to Rankine’s formula it would just have been 
on the point of overturning had it been 1*448 feet thick. 
Fig. 2. 
According to the view adopted in this paper (3 will assume a 
value such that the overturning couple will be a minimum. Taking 
39° 48', as within the errors of observation 40°, an examination of 
