hermometer from 66 to 69
degrees at noon in the shade. I could make no lunar observations for the
longitude, but by the help of the timekeeper I have computed the
situation of the town of Santa Cruz to be 28 degrees 28 minutes north
latitude and 16 degrees 18 minutes west longitude. I observed the
variation by two compasses to be 20 degrees 1 minute west: this much
exceeded what I could have imagined; for in 1776 I observed it only 14
degrees 40 minutes west; a difference of above five degrees in eleven
years: and this makes me reflect on the uncertainty of obtaining the
exact deviation of the magnetic pole, and of course its annual variation
which never can be accurately ascertained unless the observations are
made always in one spot and with the same compass.

Tenerife, though considerably without the tropic, is so nearly within the
limits of the tradewind that navigators generally steer to it from the
eastward. The road of Santa Cruz lies on the east side of the island, at
the end of a range of craggy hills, barren and very lofty, along with you
sail west by south by compass into the road, with a sea unfathomable
until near the shore. The anchoring ground may be accounted from fifty
fathoms to twenty, or even fifteen. The bank is very steep and gives but
little time to sound; for which reason it should be done effectually with
a heavy lead, or a ship will be too near in before a stranger is aware of
it: he will likewise too soon expect to find bottom, owing to the great
deception of the adjacent high land. To obviate these difficulties it is
necessary to observe that while a town which lies some distance to the
southward of Santa Cruz is open with the castle on the south part of the
road, though you may appear near to the shore, there is no anchorage; but
after it is shut entirely in you get on the bank. The church bearing west
or west by south and the south point of the road south-west half south to
south-west by west is a good situation for anchoring: the depth about
twenty-five fathoms. The distance from the shore will be three quarters
of a mile; and the southernmost land that can be seen then will be a half
or quarter point of the compass farther out than the south point of the
road.

The bottom is black soft mud, with some patches of rocks; for which
reason vessels that lie here any length of time buoy their cables. This
precaution, besides being useful in that particular, they think makes
them ride more easy