52 BULLETIN 835, IT. S. DEPARTMENT OF AGRICULTURE. 
The remaining 22 sets of observations Trere divided into two groups, 
and the equation of this parabola was derived as follows : 
log x 2^=13.751 log (^+5.5)2^=10.481 
2^= 17.124 2^= 14.061 
A = 3.374 A = 3.579 
„ - a:579 -i 6 lo - (y»+") 2 22 =24.542 
— 3.374 — ' 30.875X1.06=32.666 
log a; 2 22 =30.S75 A = 1.876—10 
1.876—10-^22 =9 r 631— 10=log a 
log (?/ 2 +5.5) =9.631— 10+1.06 log x 
y 2 =0.43 a? 1 - 06 — 5.5 
Since y. 2 —y x —y. y=y 1 —y 2 
then y= 21.39 a? - 4 — (0.43a? 106 — 5.5) 
The values calculated from this equation are tabulated and the 
differences from the values of y as obtained in the experiment are 
noted. 
When the curve resulting from the plotting x or y against log x 
or log y is straight, the exponential curve is derived in the same man- 
ner as for a parabola. The data are divided into two groups and the 
value of a and log a foimd. 
log ?/=log a — nx log £ represents the equation for both groups, so 
that log a can be eliminated by subtracting one from the other. 
n= lo gy.-logy, . wMch j £=04343 
log £ (log X 2 — log X x ) 
log r/=log y — nx log £ 
In several cases it was found that for high values of x and y the 
curves were straight lines and the equations for these straight lines 
found. 
Subtracting the values of y x in the equation y 1 =mx-{-b from the y 
values of the data gave values of y 2 . 
The log y 2 plotted against x gave straight lines, so that the curve 
for these low values of x and y were exponential curves which were 
derived as explained above. 
The formula? for the curves representing moisture movement in 
the flumes held at different angles when filled with Riverside heavy 
decomposed granite loam (Placentia loam) were as follows: 
Flume No. 42 (45° up) : 
y=33.7+0.12aj— (18.5s- - 2 *) 
