BLAKE TftIGONOMETBf. 
51 
hiark D. The angles subtended by A, at each end of the base, were 
found to be, C 94°, D 63°; with these angles and the base CD, I 
computed the side B C by Case 1, Table 11. Then, as B C is the base 
of the right-angled triangle A B C, I computed the height of the A 
by Case 2, Table I. Should a sextant be used, the angles A C D and ADC 
will be taken, and with these, and the base CD, compute the side 
A C by Case 1, Table II. Then as A C is the hypotlienuse of the right- 
angled triangle ABC, the height of the point A can be computed by 
Case 1, Table I. 
(5.) The distance between two inaccessible peaks C and D (Fig. 5) 
being required, I measured a base, A B, of 1000 yards, setting up a mark 
at each end. I then measured the angles between the two peaks, at both 
ends of the base, and found them to be:—at A, 37° and 93°; at B,43° 
and 111°. In the triangle A B C, by subtracting the sum of angles A and 
B, = 136°, from 180°, I found the angle C to be 44° ; by a similar process 
I found the angle D in the triangle A B D to be 32°, and in the triangle 
B C D, by subtracting 43°, the smaller angle, from 111°, the greater, I 
found the angle at B = 68°. Haying thus found all the necessary data 
in the triangle ABC, I computed the side CB ( Case 1, Table II.), and 
in the triangle A B D, I computed the side D B ( Case 1, Table II.). With 
the sides C B and B D, of the triangle BCD and the included angle B, I 
computed the side D C (the distance between the inaccessible peaks) by 
Cases 4 and 5, Table II 
To find the Meridian by a Watch 
When the BUD is visible, the position of the meridian line Can be 
approximately determined in the following manner by a watch set to 
local timeTurn the face of the watch to the sttn in such a manner that 
the hour-hand shall point to the sun, or, in other words, until the hour- 
hand itself shall be directly over its shadow. Half-way between the 
place of the hour-hand and XII. will be the south point in north 
latitude, and the opposite point of the dial will be the north point. In 
south latitude the reverse of this would be the case, while in the tropics 
the position of the north and south points would depend on whether the 
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