SURVEY OF THE BRITISH ISLES FOR THE EPOCH JANUARY I, I88G. Gl 
Stranraer.— Aug. 28, 1888. 
G. M. T. 
Station. 
Instrument. 
Observer. 
Declination. 
h. m. 
O / 
II 35 
1 
61 
T. 
21 137 
10 54 
2 
60 
R. 
21 12-5 
13 G 
2 
>5 
21 13-0 
During tlie survey we employed various chronometers, some of which were hired 
from Messrs. Dent, and others were lent to us by the late Professor Baleour 
Stewart, F.R.S., and by Captain Wharton, B.N., F.Pt.S., Chief Hydrographer to 
the Admiralty, to whom our thanks are due. 
We enjoyed an important advantage over our predecessors in that we were able to 
determine the rates of our chronometers frequently by comparison with Greenwich, 
by means of the 10 A.m. and 1 p.m. telegra]j]iic signals, of which the former is sent to 
all post-offices in the kingdom. We have to thank Mr. Preece, F.Pt.S., Chief Elec¬ 
trician to the General Post-office, and Mr. J. C. Lamb, the Head of the Telegraph 
Department, for their kindness in giving or obtaining for us permission to receive 
the signals. Many of the local post-office officials not only afforded us every facility 
for correcting our chronometers in accordance with their instructions, but gave us 
additional help in the selection of suitable stations. When possible, we received the 
signal every day, and rarely omitted more than two consecutive days. At places 
where the signal had undergone one or more re-transmissions, an error on this account 
was inevitable. By the kindness of the Earl of Bosse, we were able to determine its 
magnitude on the occasion of our visit to Parsonstown. The time signal was observed 
both by Professor Pucker and Herr Boddekker, the Superintendent of Lord Posse’s 
Observatory, who agreed exactly as to the apparent error of the chronometer. The 
value thus obtained differed by 4 sec. from that given by the observatory dock, the 
error of which was known from star observations. We are inclined to think that this 
amount was rarely exceeded, or the rates would have varied more widely than was 
actually the case. No special precautions against error had been taken at Parsons¬ 
town, whereas in many districts we had, when practicable, made arrangements at the 
central office that particular care should be taken on those mornings when we 
informed the authorities that we intended to receive the signal. We have on several 
occasions received at the same post-office signals sent by two different routes, 
involving re-transmission, and have never detected any appreciable difference. 
When visiting outlying stations at sea we kept one chronometer on board in a fixed 
position. This served as the standard. Another instrument, which was frequently 
compared with it, was used for making the comparisons with Greenwich and for the 
work of the actual observations. At these periods of our survey longer intervals 
necessarily elapsed between successive receptions of the time signal, during which we 
