30 
ym. (I. I. TAYLOR ox TTDAT. FRICTION IN THE IRISH SEA. 
Differentiating (48) it will he found that 
'Ztt 
-p;;; COSeC 
2770’ c/.r 
r 
T 
d 
/a 
h., 
0-67 x2 
(51) 
Since // is small, //j and Jio may he taken as a and h in places where they are not being 
differentiated. Hence, since o/h = 1'8*, the right-hand side of (51) is equal to 
()‘67 X 2 
(1-8-1)^ ~ 
Differentiating (50) 
and (51) hecomes 
2-lcT 
277 cosee 
2^/1 
•T 
d (/jj\ _ a 4o) sin A 
dii\hj h c 
(52) 
(53) 
(Combining (52) ami (53) with (47) 
, dx 
tan t) = -— = 
d// 
2’lcT a 4(»)shiA\ 
- X -- 
277X h c / 
277 cosec“ 
cT 
In ( 54 ), T = 12’4h., and from (43), 
hence 
also 
, 277a: 
cot —2 44, 
cl 
cosec* = 1 + (2'44), = 7, 
w, the angular ve 
Hence 
and 
. , . . (54) 
7 of the eartli in radians per houi' is — , and sin A = Off9. 
2 4t 
t,„fl=2'lxl2-4xr8x4^2.^„.„g^,.,.gg 
/ X 277 24 
0 = 41°. 
The agreement l:)etween 
could he expected. 
and the measured angle, 36|-°, is quite as good as 
See equation (45). 
