4 
MR. G. 1. TAYLOR ON TIDAL FRICTION IN THE IRISH SEA. U 
the velocities of the tidal streams at various states of the tide at various lightships 
in the neighbourhood of the Arklow-Bardsey section. 
On inspecting the curves shown in that figure, it will be seen that the maximum 
current is at about 3h. before H.W. at Dover. It is H.W. at Dover at llh. 7m. 
full and change, and it is H.W. on the Arklow-Bardsey line at 8h. 10m.* full and 
change. Hence it is H.W. on AB 3h. before H.W. at Dover, i.e., at the time of the 
maximum tidal current. 
Since H.W. coincides with the time of maximum current, the difterence in range at 
spring tides between those at Arklow and those ^t Bardsey should be 2x57 feet 
= 11'4 feet. The measured range at Bardsey at spring tides is 15 feet, while that at 
Spe< 
k 
id in 
nots 
/ 
Up-( 
k 
2kann 
el cu 
rrent 
/ 
Z/ 
/ 
. 
■******^ 
5 
/ 
/< 
t 
/ 
\/ 
\ 
p 
i 
/ 
/ ^ 
/ > 
f / 
^ / 
i / 
/ 
../ 
c 
\ V 
r\ •_] 
Hours 
after 
> 
High 
water 
1- 1 
-Dove 
J 
/ 
3 / / 
/ 
r A 
AA 
/ 4' 
..°*T[o 
.• 
F 
5 
urs be 
.fore 1 
] 
ater - 
HW 
Dover 
T \\ 
\ 
\. 
/ 
/ /x' 
f 
^ \ 
o 
> 
\ 
_ 
f/ 
c 
/ 
X 
Down- 
Ckartr 
el cur 
\ 
reuA ’ 
c 
\ 
/ 
c 
N.Ar: 
S.Axl 
Cnrn 
vlow 
How 
a.rvon 
o —— - 
X 
'"■X 
sj 
fs. 
/ 
Fig. 2. Curves showing the velocity of the tidal currents at three light ships in the South Channel 
to the Irish Sea at various states of the tide. 
Arklow is 4 feet. The difterence, 11 feet, is almost exactly equal to the calculated 
difterence ll|- feet. 
The accuracy with which this calcidation is verified by observation is very good 
evidence that the sea actually slopes in the way we shoidd expect from the current 
ineasurements, that is to say, uniformly from Bardsey Island to x4.rklow. It is not 
necessarj^, therefore, for our purpo.se to have actual tidal measurements in mid¬ 
channel, though it is to be hoped that the.se conclusions will some day be te.sted by 
observation. 
* See p. 1-5 later. 
