A Voyage to Terra Australis — Volume 1 eBook

This eBook from the Gutenberg Project consists of approximately 594 pages of information about A Voyage to Terra Australis — Volume 1.

A Voyage to Terra Australis — Volume 1 eBook

This eBook from the Gutenberg Project consists of approximately 594 pages of information about A Voyage to Terra Australis — Volume 1.
The Latitude of the tents in Princess-Royal Harbour, from three
meridian zenith distances of the sun, observed with Ramsden’s universal theodolite, was
                                                      35 deg. 2’ 5” south.

Longitude from thirty-one sets of distances of the sun east and west of
the moon, of which the particulars are given in Table I. of the Appendix to this volume,
                                                     117 deg. 53’ 10” east.

These being reduced by the survey to BALD HEAD, at the entrance of the sound, will place it in

Latitude                                              35 deg.  6’ 15” south. 
Longitude                                            118 deg.  0’ 45” east.*

The mean rates of the time keepers, deduced from equal altitudes taken on and between Dec. 15 and Jan. 1, and their errors from mean time at Greenwich, at noon there on the last day of observation, were as under: 

h ’ " "
Earnshaw’s No. 543, slow 0 21 46,69 and losing 6,46 per day. 
No. 520, 0 51 2,81 16,72
Arnold’s No. 176, 1 0 45,46 9,26
No. 82 went too irregularly to be worth taking.

The longitude of the tents given by the time keepers on the first day of observation, with the Cape rates, was as follows: 

Earnshaw’s No. 543, 118 deg. 14’ 49” east.
               520, 117 59 22
Arnold’s 176, 118 1 14

The two first, which generally throughout the voyage showed themselves to be the best time keepers, were on a mean 13’ 56” to the east of the lunar observations; but by using rates accelerating in arithmetic progression from those of the Cape of Good Hope to the new ones of King George’s Sound, the mean of Earnshaw’s two time keepers will then differ only 8’ 19” to the east in forty-four days.  In fixing the position of places from Cape Leeuwin to the Sound, these accelerating rates have been used; and the longitude has been further corrected by allowing an equal proportion of the error, 8’ 19”, according to the number of days after Nov. 1, when the last observations were made at the Cape of Good Hope.  In the Appendix, the nature of these corrections is more particularly explained.

[* The situation of Bald Head, in captain Vancouver’s chart, is 35 deg. 6’ 40” south, and 118 deg. 16’ 30” east from lunar observations which were not corrected for the errors of the astronomical tables.  The situation assigned to Bald Head in the voyage of the French admiral D’Entrecasteaux, is 35 deg. 10’ south, and 118 deg. 2’ 40” east; but since the admiral passed it at six in the evening, and in blowing weather, an error of a few minutes may have entered into both latitude and longitude.]

The height of the thermometer at the tents, as observed at noon, varied between 80 deg. and 64 deg..  On board the ship, it never exceeded 701/2 deg., nor was below 60 deg..  The range of the barometer was from 29,42 inches in a gale of wind from the westward, to 30,28 inches in a moderate breeze from south-west.

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A Voyage to Terra Australis — Volume 1 from Project Gutenberg. Public domain.