88 
Angle | icht ofS,| Value of R. | Value of R 
Repose 8 *| when c= 0° | when c=10° 
| Water, .° 3 z 0° 62:5ibs. R=311hk2? |R=SI12 A? 
2 | Fine dry sand, c 33° 92 — R=138h? |R= 48h? 
3 | Do. moist . 1h) R= 17:85h?} R= 6:2 h? 
4 | Quartz sand, dry, 35° 102 — R=1377h?} R= 46h? 
Now, using the same data, and calculating from equations 
(6) and (2) here given, the values will be as follow: 
Value of R. | Value of R 
Angle when 6 = 0, | whenb= 10° 
of Weight of W.| and C D ver- | and D E ho- 
Repose. tical: equa-| rizontal: 
tion (6). | equation(2). 
1p Waterss. i 0° 62 5ibs. | R= 312A? | R=SIZR? 
Dp ae sand, dry, A 33° 92 — R=13-5Ah? | R= OTe 
3 moist, io R=175h2 | R=12°6h2 
4 le sand, dry, 35° 102 — R=13:3/? | S35 
The values in the last column have been calculated from 
equations (2) and (5) respectively, which gave the same 
results when the latter is multiplied by sec*b, as 1? 
sec?b = n?: they are fully double those given by Tredgold, 
and made use of by him in calculating the dimensions of re- 
taining walls given in another Table. The differences in the 
Tables, when b= 0, are immaterial. Equation (25) is, how- 
ever, incorrect, as will be seen by squaring the second part of 
equation (3) here given, actually, when we get 
tanctanb+1 >) 
hew A 
= Stan © (tane-+tanb+-—— —2 tanctanb+1-+4— saat 
tanec + l 
Sani te in Tredgold’s 
tance tanz+ l 
tan?7 
this being the case, his equation is then reducible to equation 
(3). Equation (23) can also be reduced to the form of equation 
(1), which is general, whether DE is horizontal or inclined. 
Whence it appears that the term 
equation (25) under the square root, should be 
> 
