174 Biographical Account of [Marcu, 
proved inall other respects, that was now submitted to examination. 
it was intended that Mr. Robison should accompany young Harri- 
son and the time-keeper ina frigate, the Deptford, to Port Royal, 
in Jamaica, in order to determine, on their landing, the difference 
of time, as given by the watch, and as found by astronomical ob- 
servation. ‘The time-keeper accordingly was put into the hands of 
Mr. Robertson, of the Naval School at Portsmouth, who deter- 
mined its rate, from nine days that it remained in his custody, to be 
22’ slow per day, and also the error to be 3” slow on the 6th of 
November at noon, according to mean solar time. 
The Deptford sailed on Nov. 18, and arrived at Port Royal on 
Jan. 19; on the 26th Mr. Robison observed the time of noon, and 
found it to answer to 4" 59’ 71” by the watch; and this being cor- 
rected for the error of 3’’, and also for the daily accumulation of 
22” for 81° 5%, the interval between the observations, the difference 
of longitude between Portsmouth and Port Royal came out 
55 9’ 47”; only 4” less than it was known to be from other obser- 
vations, 
The instructions of the Board further required that, as soon as an 
opportunity could be found, the same two Gentlemen should return 
with the watch to Portsmouth, that, by a comparison of it with the 
time there, the total error, during both voyages, might be ascer- 
tained. The opportunity of return occurred sooner than they had 
any reason to expect; for the Spanish war having now broke out, 
an alarm of an invasion of Jamaica from St. Domingo occasioned 
the Governor to dispatch the Merlin sloop of war to England, to 
give intelligence of the danger. Mr. Robison and Mr. Harrison 
obtained leave to return in the Merlin, and sailed on the 28th, 
having been but a few days in Jamaica. This voyage was an epitome 
of all the disasters, short of shipwreck, to which seafaring men are 
exposed. They experienced a continuation of the most tempestuous 
weather, and the most contrary winds, from the moment they 
guitted the Bahamas till they arrived at Spithead. To add to their 
distress, the ship sprung a great leak, 300 leagues from any land, 
and it required the utmost skill and exertion to keep her from sink- 
ing, Ina terrible gale, on March 14, their rudder broke in two: 
so that they could no longer keep the ship’s head to the wind; and 
if the gale had not speedily moderated, they must inevitably have 
perished. When the voyage was near a conclusion, and they were 
congratulating themselves on the end of their troubles, the ship was 
found to be on fire, and the flames were extinguished with great 
difficulty. They reached Portsmouth on March 26; and on 
April 2 the mean noon by the watch was found to be at 11° 5)’ 
312”; and, making correction for the error and rate, this amounted 
to 11" 58’ 61”; so that the whole error, from the first setting sail, 
was only 1’ 531”, which, in the latitude of Portsmouth, would not 
amount to an error, in distance, of 20 miles. 
When Mr. Robison undertook the voyage to Jamaica, he made 
no stipulation for any remuneration, and Lord Anson assured him 
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