Chapter XXII: Appendix: A. Section 10

UPON THE GEOGRAPHICAL POSITIONS OF THE FIXED POINTS OF THE SURVEY.

The observations for determining the longitudes of the various parts of the coast were taken with a circle and a sextant by Troughton: besides these valuable instruments we had three chronometers of Arnold's make, namely, 413 (box) 2054 (pocket) and 394 (pocket); of which the two first were supplied by the Admiralty. At the end of the fourth year, in consequence of 394 having stopped, a fourth chronometer, made by Parkinson and Frodsham (Number 287 box) was purchased in the colony, and proved to be a most excellent watch.

The situations of the following places, which were either fixed by us or adapted from other authorities, served as the basis of the chronometrical determination of the longitudes of the intermediate parts.

The flagstaff of FORT MACQUARIE on the north-east head of Sydney Cove in PORT JACKSON (the Cattle Point of Flinders, and otherwise Bennelong Point) is in latitude 33 degrees 51 minutes 28 seconds South and longitude 151 degrees 15 minutes 26 East, being, according to the ensuing table, the mean of all the observations that have been taken.

Latitude (in degrees minutes seconds) observed by:

Captain Flinders, in 1795 and 1802: 33 51 45.6. De Freycinet in 1802: 33 51 21. King (reduced) 1817: 33 51 18. Sir T. Brisbane (reduced) 1822: 33 51 30.

Mean Latitude of Fort Macquarie 33 51 28.

Longitude (in degrees minutes seconds) observed by:

Captain Cook, reduced from his observations at Botany Bay, 1770: 151 11 32. Captain Hunter, 1788: 151 19 43. Lieutenant Dawes 1788: 151 18 50. Lieutenant Bradley: 151 20 38. Malespina: 151 17 53. Messrs. Broughton and Crosley, 1795: 151 9 3. Captain Flinders, 1795-6: 151 17 12. Ditto 1802: 151 11 49. Captain De Freycinet, 1802: 151 8 32. M. D'Espinosa by an eclipse of sun and occultation of Jupiter 1st and 2nd Satellites, 1793: 151 12 45. Governor Bligh, 1806, eclipse of sun: 151 17 49. Captain P.P. King, 1817, eclipse of sun, calculated by Mr. Rumker: 151 17 29. Sir Thomas Brisbane, 1822 (the mean of six eclipses places his observatory in 151 degrees 15 minutes 20 seconds): 151 15 32. Mr. Rumker, eclipse of sun at Parramatta, reduced to Fort Macquarie: 151 17 30.

Mean Longitude of Fort Macquarie 151 15 26.

PERCY ISLAND (Number 2). The longitude of the south-west end of this island is by Captain Flinders' observation in 150 degrees 13 minutes East.

ENDEAVOUR RIVER. The observatory, which was placed within a few yards of the shore on the south side of the entrance (the summit of the highest bush near the extremity of the opposite sandy beach, bearing by compass West 3 degrees 40 minutes South) was found to be situated in latitude 15 degrees 27 minutes 4 seconds, and longitude 145 degrees 10 minutes 49 seconds. (See note, Appendix A.)

GOULBURN ISLANDS. The observations were taken upon Bottle Rock, the largest of two rocky islets at the north end of South-west Bay; but the results were so doubtful and unsatisfactory, that the longitude determined by the chronometers was preferred. The following are the observations that were taken to fix its situation, namely:

Latitude by fourteen meridional altitudes of the sun l. l. on the sea-horizon, taken in various parts of the bay, and reduced by survey to Bottle Rock 11 37 24.

The difference of longitude between Bottle Rock and Cassini Island by chronometers, taken in:

1819: 7 40 47. 1820: 7 40 00. 1821: 7 38 28.

Mean difference between Cassini Island and Bottle Rock: 7 39 45.

Longitude of Cassini Island from Careening Bay, by survey: 125 38 46.

Longitude of Bottle Rock, by chronometer, from Cassini Island: 133 18 31.

The mean of the results of the lunar distances that were taken during the years 1818 and 1819, gave for the longitude of the rock 133 degrees 31 minutes 58 seconds East. On our last voyage the mean of the Bathurst's and Dick's watches made it 133 degrees 19 minutes 40 seconds, which was finally adapted, since it accorded better with the chronometrical difference between its meridian and that of Cassini Island. I have never been able to account for this extraordinary disagreement between the results of the lunar distances and the chronometers, since the former were taken with the sun on both sides of the moon, and seemed to be very good.

CAREENING BAY. This place was fixed by a series of observations, in latitude 15 degrees 6 minutes 18 seconds South, and 125 degrees 0 minutes 46 seconds East. (See Appendix A. in a note.)

KING GEORGE THE THIRD'S SOUND. The longitude of this place was adapted from the observations and survey of Captain Flinders, as follows; namely:

The tent on the east shore of the entrance of Oyster Harbour. Latitude 35 degrees 0 minutes 17 seconds, and longitude 117 degrees 56 minutes 22 seconds.

The sandy beach under the low part of the land of Bald Head (the first sandy bay round the head) is in latitude 35 degrees 6 minutes, and longitude 117 degrees 58 minutes 6 seconds.

COEPANG, in the Island of Timor. The situation of the flag-staff of FORT CONCORDIA, where our chronometers were rated, is in latitude 10 degrees 9 minutes 6 seconds, and longitude 123 degrees 35 minutes 46 seconds, according to the observations of Captain Flinders.

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