1802.
April.
Tuesday 6.
| The variation observed on shore, | with the theodolite, was | 5° | 48′ east. |
| D°. with azimuth compass, No. I. | with the theodolite,--- | 2 | 58 |
For this difference between the instruments, I find it difficult to account satisfactorily; but it is the same way, and nearly similar in quantity to what was observed in Lucky Bay. The true variation on board the ship, deduced from azimuths taken at anchor two miles to the north-east, and using the compasses No. 1 and 2, was as before mentioned, 4° 13′, nearly the mean of the above; but the bearings taken with the theodolite at Kanguroo Head and Prospect Hill showed only 2½° east, as compared with the bearings on board the ship. There can be little doubt of the existence of magnetic substances in the lands about here, more particularly, as I think, in Yorke's Peninsula; and there will presently be occasion to notice more instances of their effect.
The approach of the winter season, and an apprehension that the discovery of the remaining unknown part of the South Coast might not be completed before a want of provisions would make it necessary to run for Port Jackson, prevented me from stopping a day longer at Kanguroo Island than was necessary to obtaining rates for the time keepers; and consequently, from examining the south and west parts of that island. The direction of the main coast and the inlets it might form, were the most important points to be now ascertained; and the details of particular parts, which it would interfere too much with those objects to examine, were best referred to the second visit, directed by my instructions to be made to this coast. When, therefore, the rising of a breeze made it advisable to get under way from Kanguroo Head, which was not until two in the afternoon, we proceeded for the eastern outlet of the Investigator's Strait; in order to prosecute the discovery beyond Cape Jervis.
The wind was at south-east; and the tide being against us, but little progress was made until the evening, when it became favourable. Our soundings were irregular, and some rocky islets being