\fdO'^ - Old Forge Coal Mines

(TOO) 1.745 ft. X 3 = 5.235 ft.,
SURVEYING. 255
the vertical rise of a 3°
slope in 100 ft., or 1 station and -——- =1.91 stations = 191 ft.
5.2o5
(701) (See Question 701, Fig. 15.)
From the instru-
ment to the center of the spire is 100 ft. + 15 = 115 ft., and
we have a right triangle whose base A D = 115 ft. and angle
A is 45° 20'. From rule 5, Art. 754, we have tan 45° 20' =
side/?/? , , ^,,,v^ side —-—— BD „ „ ,,„..
; whence, 1.01170 = -— ox B D — 11(5.345
;
115 llo
feet. The instrument is 5 feet above the level of the base;
hence, 116.345 ft. + 5 ft. = 121.345, the height of the spire.
(702) Apply formula 96.
Z= (log h - log H) X 00,384.3 X (l + ^ + ^g'~^^° ),
(See Art. 1304.)
log of //, 29.40 = 1.46835
logoff/, 26.95 = 1.43056
Difference = 0.03779
^ +/'-04° _ 7 4 + 58-64
^+ -^+ _-l-«7^5.
900 900
Hence, Z= .03779 X 60,384.3 X 1.0755 = 2,454 ft., the
difference in elevation between the stations.
(703)
(704)
(705)
See Art. 1305.
See Art. 1308.
See Art. 1308.