344 
MR. WARREN DE LA RUE ON THE 
For Frodsham 3094. 
h 
m secs. 
August 10 
0 
0 
2*8 slow. 
August 11 
0 
0 
3 slow. 
August 13 
0 
0 
2*7 slow. 
August 14 
0 
0 
3 slow. 
August 15 
0 
0 
2*2 slow. 
August 16 
0 
0 
2*6 slow. 
August 17 
0 
0 
2*8 slow. 
August 18 
0 
0 
2*7 slow. 
August 20 
0 
0 
2*5 slow. 
its average daily rate being losing 0‘03 
second 
, whereas, be: 
0’91 second. 
On the 16th of July, Mr. Otto Steuve, Dr. Winnecke, and Lieut. Oom visited my 
station ; and I took advantage of their doing so, to make a comparison of chronometers. 
Dr. WiNNECKE estimated the error of Frodsham No. 3094 to be fast of Greenwich mean 
time 7’5 seconds; consequently as the pocket chronometer Frodsham No. 9768 was slow 
of No. 3094 42’5 seconds, it follows, from this comparison, that it was — 42 '5 seconds 
+ 7’5 seconds =35 seconds slow of Greenwich mean time, which differs by only —Id 
second from the error assigned to it, by applying its mean daily losing rate of 1-71 
second. 
It appears, therefore, that the pocket chronometer could be relied on up to the 16 th 
of July. On correcting the assumed error from Greenwich mean time of No. 3094 by 
comparisons with the pocket chronometer, we obtain the following : — 
Frodsham No. 3094. 
Computed error from G-reenwich 
mean time, taking No. 9768 
as the standard. 
July 9 
fast 10*9 seconds 
July 10 
fast 11*2 seconds 
July 11 
fast 10*0 seconds 
July 12 
fast 
8*3 seconds 
July 13 
fast 
7*6 seconds 
.July 14 
fast 
7*4 seconds 
July 15 
fast 
7*2 seconds 
July 16 
fast 
6*4 seconds 
Assumed error from Greenudch mean 
time applying its average rate. 
fast 9 ’9 seconds 
fast 10‘8 seconds 
With the advantage of the comparison made on the occasion of Mr. Steuve’s visit, 1 
have confidence in assuming the error of Frodsham 3094 to have been from -|-6‘4 to 
+ 7 ’5 seconds, say +7 seconds, on July 16 at noon. 
On the 19th the Astronomer Royal and his party honoured me with a visit, and I had 
the great satisfaction of hearing from our leader that he was well satisfied with the sue- 
