[ 388 ] 
3® If/ =1 o,866 * 
for 12 fl. = °>°99 (& Ct 
i8 • = 0,099 (Gfc. 
g6 = 0,104 i & c - 
an infinite number = 0,103 
In this third cafe the difference is ffili very fmall, 
and the effect refulting from 36 float- boards will 
be of the effect of a Angle vertical float- 
board. 
XXXVI. 
