THE FLOW OF WATER IN DRAIN TILE. 37 
Table 6. — Individual tile formula and revised intercept values. 
1 2 
1 
3 
4 
5 
6 
7 
8 
Tile. 
Velocity. 
Num- 
ber of 
ob- 
serva- 
tions. 
Formulge derived sep- 
arately for each tile 
size. 
Revised 
intercept 
values 
m'. 
Kind. 
Nom- 
inal 
size. 
Actual 
average 
diame- 
ter. 
Area of 
bore. 
Hard-bumed clay. 
Do 
Inches. 
4 
5 
6 
8 
10 
12 
4 
5 
6 
8 
10 
12 
Feet. 
0.3398 
.4193 
.5184 
.685 
.836 
.9857 
.3280 
.4127 
.497fl 
.6585 
.8274 
.9915 
Sq.feet. 
0.0907 
.1381 
.2111 
.3685 
.5489 
.7631 
.0845 
.1338 
.1940 
.3406 
.5377 
.7721 
Feet per second. 
0.607 to 3.328... 
.634 to 4.030... 
.765 to 3.368... 
.893 to 4.423... 
1.168 to5. 717... 
1.176 to 4.002... 
.504 to 3. 056... 
.640 to 3. 891... 
.705 to 3.274... 
.914 to 4.959... 
.898 to 5.486... 
1.183 to 2.935... 
14 
17 
6 
15 
18 
6 
8 
9 
7 
18 
26 
4 
s= 0.0014797 ys-o^ae 
s= .0010494 y-s™ 
s= .000819 y'-832i 
s= .000617 yi-991^ 
s= .000384 yi-9918 
s= .0003185 yi-9907 
s= .0018651 yi-8509 
s= .001077 yi-9183 
s= .000856 y2-oio4 
s= .0005674 y2-0373 
s= .0005003 yi-9632 
s= .0003449 y2-0059 
0.0015185 
. 0010524 
Soft-burned clay. . . 
Hard-burned clay. 
Vitrified 
.000761 
.0006297 
. 0003927 
Do 
. 0003241 
.0017954 
Do 
. 0010444 
Do 
. 0008791 
Do 
. 0006079 
Do 
. 0004997 
Do 
. 0003546 
Since for the same kind of tile the exponents V vary for the differ- 
ent sizes, the mean of the exponents has been taken as correct; thus, 
For clay tile , 2=1. 96859 . 
For concrete tile,2=l. 96433. 
Using these mean values of z instead of the values derived for each 
separate size of tile, new values, m' , were computed for the inter- 
cepts on the unity vertical axis, as follows : 
For clay tile, log m' =log s- 1.96859 log V (20) 
For concrete tile, log m' =log s- 1.96433 log V (21) 
These values of m' are given in column 8 of Table 6. 
To introduce the mean hydraulic radius into the formulae, the rela- 
tion of the values of m' to the hydraulic radii for the different sizes 
of concrete tile is represented by the formula, 
m 
eR' 
(22) 
in which e and x are determined analytically, by a method similar to 
that previously explained, as follows: 
Tile 
size. 
Meaa 
hydraulic 
radius 
R. 
Intercept 
values 
logi2. 
Inches. 
4 
5 
Feet. 
0.0915 
.1154 
.1379 
.1840 
.2316 
.2729 
0.0017954 
.0010444 
.0008791 
.0006079 
.0004997 
.0003546 
8.961421 Sum= 27. 16319 
9. 0622nMean= 9.05439= Z>r. .- . 
9. 13956] Antilog Dt= 0.1133. . . . 
9.26482] Sum= 28.0655 
9.36474 lMean= 9.35519= Er. 
9.43600J Antilog Er= 0.2265 . 
7.2541711 Sum= 21.217044 
7.018853^Mean= 7.072348= Dm' 
6.944020) Antilog Dm'= 0.0011813 
6.7838501 Sum= 20.032332 
6.69871llMean=6.677444= ^m' 
6.549771J Antilog Em'= .00047582 
Sum= 55.22875 
Mean= 9.20479= 
AntUog Fr= 0.1602 
Sum= 41.249376 
Mean= 6.874896= i^jn 
Antilog Fm'= 0.00074971 
