1773*
January.
» —^ _
Friday 15..
Myfelf being the mean of fix diftances
fun and moon _
Mr. Wales, ditto
Ditto - - ditto -
Lieutenant Clerke, ditto
Mr. Gilbert, ditto - -
Mr. Smith, ditto - ' - -
of the ) 0 I
(40 1 45 E.
- 3.9 89 45
- 39 5^ 45
- 39 38 o
39 48 45
- 39 18 is
Mean 39 43 ia
Mr. Kendal’s watch made - - - 38 41 30
Which is nearly the fame difference as the day before. But
Mr. Wales and I took each of us fix diftances of the fun and
moon, with the telefcopes fixed to our fextants, which
brought out the longitude nearly the fame as the watch.
The refults were as fol lowsBy Mr. Wales 38° 35' 30", and
by me 38° 36' 45".
It is impoffible for me to fay whether thefe or the former
are the neareft the truth; nor can I aflign any probable
reafon for fo great a difagreement. We certainly can ob-
ferve with greater accuracy through the telefcope, than
with the common fight, when the fhip is fufficiently fteady.
The ufe of the telefcope is found difficult at firft; but a
little practice will make it familiar. By the affiftance of the
watch, we ffiall be able tg difcover the greateft error this
method of obferving the longitude at fea is liable to;
which, at the greateft, does not exceed a degree and an
half, and in general will be found- to be much lefs. Such
is the improvement navigation has received by the aftro-
nomers and mathematical inftrument makers of this age •
by the former, from the valuable tables they have communicated
to the Public, under the direffion of the Board of
Longitude, and contained in the aftronomical ephemeris;
and by the latter, from the great accuracy they obferve in
making
making inftruments, without which the tables would, in a
great meafure, lofe their effect. The preceding obfervations
were made by four different fextants, of different workmen.
Mine was made by Mr. Bird ; one of Mr. Wales’s by Mr. Dol-
lond ; the other, and Mr. Clerke’s, by Mr. Ramfden ; as alfo
Mr. Gilbert’s and Smith’s, who obferved with the fame inftrument.
'773- January.
Friday 15.
Five tolerably fine days had now fucceeded one another.
This, befides giving us an opportunity to make the preceding
obfervations, was very ferviceable to us on many other
accounts, and came at a very feafonable time. For, having on
board a good quantity of freffi water, or ice, which was the
fame thing, the people were enabled to waffi and dry their
cloaths and linen; a care that can never be enough attended
to in all long voyages. The winds, during this time, blew in
gentle gales, and the weather was mild. Yet the mercury
in the thermometer never rofe above 36 ; and was frequently
as low as the freezing point.
In the afternoon, having but little wind, I brought to under
an ifland of ice, and fent a boat to take up fome. In
the evening the wind frefhened at Eaft, and was attended
with fnow fhowers and thick hazy weather, which continued
great part of the i6tb. As we met with little ice, I Saturday 16.
flood to the South, clofe hauled; and at fix o’clock in the
evening, being in the latitude of 64° 56' South, longitude
39° 3 5' Eaft, I found the variation by Gregory’s compafs to
be 26° 41' Weft. At this time, the motion of the fhip was fo
great, that I could by no means obferve with any of Dr.
Knight’s compaffes.
As the wind remained invariably fixed at Eaft, and E. by
S., I continued to ftand to the South; and on the 17th, be- Sunday 17.
V ol. I. G tween