344
17. The rate of the Brock Standard Mean Time Clock, reduced to 75°, appears to depend to some extent upon the position of the weight; going faster immediately after the clock is wound up, and gradually more and more slowly until the time of the next winding. This seven-day period has been observed ever since the clock was erected in August 1891, as is shown in the following table :-
Mean Daily Rate for 3 days after
Interval.
Weeks
winding
Jan. 5, 1892-Jan. 16, 1893 Jan. 20, 1893-Dec. 21, 1893 Jan. 23, 1894-Mar. 5, 1895
54
+ 2.583
48
+ 2.442
58
1.392
Mean Daily Rate for 4 days before
winding + 2.651
+ 2.553 1.336
Difference
0.068
0.111
0.056
The daily change of rate due to this cause has been determined for the intermediate period and together with the observed arc of the pendulum corresponding thereto is shown below. It is to be remarked that the clock is regularly wound on Monday morning, and that the rate for the 24 hours subsequent to that is entered opposite to the day. The sudden increase of the arc of the pendulum on Saturday is due to the fact that it is then often read by Mr. FIGG, whose habit of observing it is to give a greater reading than Mr. PLUMMER who has made the other observations :--
Mean Daily Rate.
Mean Arc of Pendulum.
3° 56′ 55′′
Monday, Tuesday,
Wednesday,
Thursday,
Friday,
Saturday,
Sunday,
+ 2*.428
+ 2.444
3 56 54
+ 2.455
3 56 46
•
+ 2.497
3
56 48
+ 2.543
3
56 3
+ 2.593
3
56 43
+ 2.571
3
56 1
18. During the year 1894 the Time Ball has been dropped daily except on Government holidays. On the 29th July it was not hoisted as one of the wires in the discharge circuit was found corroded. On the 19th September, the 25th and 30th of the same month, and also on the 5th October the wind was two strong to risk hoisting the ball. The line was interrupted on the 6th and 7th October. The ball failed once in 1894. The failure was due to the top of the cylinder being dirty with thickened oil.--- The following table exhibits the errors of the time-ball in 1894. It will be seen that these never exceeded a half a second perceptibly, and that in nearly three out of four cases there was practically no error noticeable. This was due to the care bestowed upon the astronomical observations by Mr. PLUMMER.
Table V.
Errors of Time-Ball in 1894.
means too late.
+ means too early.
Date.
Jan.
Feb.
March. April. May. June. July.
Aug. Sept.
Oct.
Nov.
Dec.
T
1,
0.1
0*.1
0*.1 +0.2 +0.2 0'.1
0.1
0.1
-0°.3
0°.1
0.1
2,
0.1
0.1
0.1 +0.3 +0.2
0.1
0.1
0.1 -0.2
0.1
0.1
3,
08.1
0.1
0.1 +0.2
+0.2
0.1
0.1
0
-0.2
0.1
0.1
0.1
4,
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
+0.2
5,
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
6,
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
+0.3
-0.2 +0.3
0.1
0.1
0.1
0.1
0.1
0
+0.2
0.2 +0.2
8,
0.1
0.1
0.1
0.1
+0.2
.1
0.1
0.1 +0.3
0.1
0.1 +0.3
9,
0.1
0.1 +0.2
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1 +0.4.:
10,
0.1
0.1 1+0.2
+0.2
0.1
0.1
0.1
0.1 +0.2
0.1
0.1
11,
0.1
0.1
0.1
+0.4
0.1
0.1
0.1
0.1
+0.2 0.1
0.1
0.1
12,
0.1
-0.2
0.1 +0.3
+0.3
+0.3
0.1
0.1
0.1
0.1
0.1
0.1
13,
0.1 -0.2
0.1
0.1
+0.4
+0.5
0.1
0.1
-0.2
0.1
0.1
0.1
14,
+0.3
0.1
0.1
0.1
0.1
0.1 +0.2
0.1 -0.2
0.1
0.1
15,
+0.4
0.1
0.1
0.1
0.1
0.1
0.1 +0.3
0.1 -0.3
0.1
-0.2
16,
+0.5
0.1
+0.2
0.1
0.1
+0.2
0.1 +0.4 0.1
0.1
0.1
-0.3
17.
1+0.5
-0.2 0,.1 0.1
0.1
+0.2
0.1
+0.4
0.1
-0.2
0.1 -0.4
18,
+0.5
-0.2
0.1
+0.2 +0.2
+0.3
0.1
0.1
0.1
-0.2 40.2
0.1
19,
+0.4
-0.3
0.1
0.1 1+0.3
0.1
0.1
-0.2
-0.2 +0.2
0.1
20,
+0.4
0.1
0.1
0.1 1+0.4
0.1
0.1
-0.3 +0.5
0.1 +.3
0.1
21,
-0.2
+0.2 0.1
0.1 +0.4
0.1
0.1
0.1
0.1
0.1
0.1
0.1
22,
0.2 +0.3 +0.2 0.1 +0.4
0.1
0.1
0.1
0.1
0.1
0.1
23,
-0.3
24,
-0.4
25,
-0.2
0.1 0.1 +0.2 +0.2 +0.8 0.1
0.1 +0.6 0.1
0.1 1+0.2
0.1 +0.3
0.1
0.1
0.1
0.1
0.1
0.1
0.1
+0.3
0.1
0.1
0.1
0.1
26,
0.1
+0.2
0.1 +0.2
0.1
0.1
0.1
0.1
0.1
0.1
27,
-0:2
0.1
0.1
0.1 +0.3 0.1
0.1
0.1
0.1
0.1
-0.2
-0.3
28,
-0.3
0.1
0.1
0.1
+0.5
0.1
0.1
0.1
0.1
.0.1 -0.8
0.4
29,
-0.13
0.1 +0.2
+0.8
.1
0.1
0.1
0.1
0.1
-0.6
30,
-0.2
0.1 +0.2
0.1
0.1
0.1
-0.2
0.1
+0.3
-0.4
31,
+0.2
0.1
+0.2
0.1
0.1
0.1
404
:
0.1