1802.
July.
This position of Cattle Point, being reduced to the entrance of Port Jackson, will be for the
| Flag staff on the south head, | latitude | 33° | 51½′ | south, |
| longitude | 151 | 16½ | east. |
Ramsden's universal theodolite was set up at the observatory, and intended to be used as a transit instrument; but from the unfavourable state of the weather and my numerous occupations, it was not adjusted to the meridian; and the rates of the time keepers were therefore deduced from equal altitudes, taken with a sextant and artificial horizon in the usual way. Their errors from mean Greenwich time, at noon there July 18, and the mean rates of going in the last fifteen days, which were selected as the best, were as under:
| Earnshaw's No. | 543, | slow | 0ʰ | 16′ | 39″,72 | and losing | 8″,63 | per day. |
| 520, | slow- | 1 | 18 | 53,00 | - - - | 19,52 |
The longitude of Cattle Point, given by the time keepers with the Kanguroo-Island rates on May 10th, the first day of observation after our arrival, was by
| No. | 543 | - | 151° | 31′ | 21″ | |
| 520 | - | 151 | 26 | 49 | east. |
The mean is 17′ 16″ more than deduced from the lunar observations; and when rates are used equally accelerating from those at Kanguroo Island, to what were found on first arriving at Port Jackson, the longitude by the time keepers would still be 14' 57",4 to the east; so that they appear to have gone less regularly during this passage than before. In fixing the longitudes of places between the two stations, the time keepers with their accelerated rates have been used; and the error of 14′ 57″,4 has been corrected by quantities proportionate to the times of observation, between April 6 at Kanguroo Island, and May 9 at Port Jackson.
The mean dip of the south end of the needle at
Cattle Point was . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
62° 52′ |
Sydney to be 151° 12′ 45″ east of Greenwich; not differing more than a minute of longitude from the above forty-four sets of corrected lunar observations.
