201 
as determined by chronometers at sea. 
The errors of the chronometers in April, were those ob- 
tained in London before the ships sailed ; those on the 25th 
August were determined at the Observatory on Dane’s Island, 
Spitzbergen, the longitude of which was determined by a 
great many observations of the distances of the- sun and 
moon for several days with Troughton’s eight inch sextants 
and reflecting circles. The rates in the column entitled 
“ Mean Rates at Sea,” are deduced by dividing the difference 
of the errors by the interval. 
The rates in the column entitled “ Mean Rates on Shore,” 
or more properly what they would have had, are means be- 
tween the rates of chronometers on shore before leaving 
England, and those obtained at Spitzbergen ; and although a 
mean between the rates of chronometers obtained at different 
times, may not accurately be the mean rate they would have 
had during the interval of those times, from the continued 
variation to which they are subject ; yet, upon comparing 
the two last columns together, of the rates thus deduced, it 
will be perceived, that in all the chronometers their gaining 
rates had either been increased, or their losing ones dimi- 
nished on ship-board, or in other words, they had all been 
accelerated. 
Nor is this acceleration peculiar to high latitudes ; it was 
observed very soon after the chronometers were put on board 
in the River, particularly in Nos. 3 and 8, which, upon ar- 
riving at Shetland, were found to have gained instead of 
losing rates, which they had in London. 
This acceleration was very soon perceptible in the chro- 
nometers taken out by the Hon. Captain Phipps, made by 
