^50 Mr I .ivingstoii mi the Thermometer as an Indkator 
tener, and tlie result reported to me below ; and tlie instant it 
fell two or three degrees, I caused tlie ship to be tacked, nor 
did it in a single instance betray me, as it invariably fell before 
we could fnd soundings with 100 fathoms. I call it a valuable 
instrument, and it truly proved so on that occasion to me ; for 
with the wind dead on shore for about twelve or fourteen days, 
we had only, in a ship of 276 tons, four men and a boy fit for 
duty, all the rest being sick, officers included, with fever ; in- 
deed, some days it was with difficulty any of us could crawl 
on deck to take an observation ; and, during that time, I al- 
most consider that, for the safety of ship, cargo and crew, we 
were indebted to the thermometer. 
It would occupy too much space, and require more time than 
I can at present devote to the purpose, to analyse the whole of 
the Thermometric Journal. Suffice it to say, that from lat. 38® 
56', and long. 62° 39', the height of the mercury gradually de- 
creased, until it seemed to rest between 74 and 76 degrees ; but 
from about long. 44° to 33° W. running on the parallel of about 
40°, or nearly so, it was extremely variable ; and in lat. 39° 40', 
long, about 34° 45' it suddenly sunk to 72J°, which at the time 
led me to suspect the vicinity of some unknown shoal. Indeed 
I am disposed to think that the previous irregularity of the in- 
strument was occasioned by the irregularity of depth of the 
Ocean ; but though this idea suggested itself to me at the time, 
I did not consider myself entitled (with a fair and stiff* breeze) to 
detain the ship on her voyage, by bringing to, in order to sound. 
It may, however, be here remarked, that all the Atlantic charts 
I have seen, depict various rocks and shoals of doubtful exist- 
ence, almost in the track we came ; and considering the proxi- 
mity of the volcanic Azores, it is not unlikely that shoals may 
really exist, or have existed, but sunk again, like Sabrina Is- 
land at St ]\lichaers. 
Near the Islands of Fayal and Pico, and in the strait be- 
tween the latter and St George’s, the mercury fell to 70J°, but 
between these islands and St Michael’s it again rose some de- 
grees. In 17 fathoms water, (when the ship wns at anchor) in 
the road of the city of Ponta del Gtida, in St Michael’s, it stood 
at 70°, and about two leagues in the offing it rose to 7^^° from 
thence it gradually subsided to 69°, at which it continued until 
the sea began to lose the deep azure of the ocean, and assume 
