A NEW METHOD OF ESTIMATING STREAM-FLOW 
171 
is the factor for converting run-off from Watershed B in c.f.s. to units of 0.01 inch of 
depth per day on that watershed. The values in column 2 are the derived values 
after one smoothing by taking means of three, holding R\ constant and assuming 
R'n constant at zero. 
Column 4 of Table 45 appears plotted on Plate 8. 
The probable errors of the constants it!',, R' 2f . . . R', were computed rigor- 
ously from the normal equations similar to equations (69), from which the constants 
were derived, and from the residuals, v, of 193 observation equations of Solution 
CC, Stream B. The probable error of S c , ±4.0, was estimated. The probable 
errors of R\, R'» and R'i were not computed, but are believed to be smaller than 
those of the corresponding unknowns derived on Stream A, viz, ±0.03, ±0.015 
and ±0.21, respectively. (Note the division of the probable error of R' t of Stream 
A by 10 to account for the different unit used in Stream B.) 
From Table 45 only 4.09 per cent of any change in storage in the drainage area 
of Stream B on a day is delivered to the stream after a lapse of 257 days (including 
the day) by travel through the ground to the stream, if the storage remains constant 
after the first of the 257 days, which is less than half the corresponding value for 
Stream A. 
For purposes of discussion it is convenient to write out the equation of normal 
flow of Stream B thus: 
+ 96+0.060r 1 +0.071r 2 +0.082r 3 +0.079r 4 +0.790r 6 +0.715r 6 +0.496r 7 +0.269r 8 
+0.403r 9 +0.210r 10 = -D' .- (77) 
which is of the form of equation (33) and corresponds to equation (76) for Stream A. 
The normal flow of Stream B was computed from equation (77) for the whole 
period March 1911 to December 1915. It is shown on Plates 13 to 17 inclusive. 
VALUES OF G FOR STREAMS A AND B 
From the computation of the normal stream-flow on Streams A and B in the 
summer months of 1911, 1912 and 1913, in comparison with the observed stream- 
Table 46 — Values of G for Streams A and B 
Stream-flow 
Value of ri the 
Stream-flow 
Value of ri the 
on preceding 
current day re- 
on preceding 
current day re- 
day 
quired to glut 
day 
quired to glut 
ground 
ground 
D' 
G 
D' 
G 
(0.001 c.f.s.) 
(0.01") 
(0.001 c.f.s.) 
(0.01") 
40 
66 
120 
38 
50 
65 
130 
36 
60 
63 
140 
34 
150 
28 
70 
60 
160 
25 
170 
24 
80 
55 
180 
23 
190 
23 
90 
49 
200 
23 
210 
23 
100 
43 
250 
22 
300 
21 
110 
40 
350 
21 
400 and over 
20 
flow, and using the criterion for flood-flows previously explained, values of G were 
obtained for various discharges as shown in Table 46, from which it appears that 
