[SOUTH COAST. INVESTIGATOR'S STRAIT.]
WEDNESDAY 24 MARCH 1802
March 24 in the morning, we got under way from Kangaroo Island in order to take up the examination of the main coast at Cape Spencer, where it had been quitted in the evening of the 20th, when the late gale commenced. The wind had continued to blow fresh from the southward, but had now moderated, and was at south-west. We steered north-westward from ten o'clock till six in the evening, and then had sight of land extending from N. 62° W. to a low part terminating at N. 17° E. distant three leagues. A hummock upon this low part was named Troubridge Hill, and at first it makes like an island. Nothing was visible to the eastward of the low land; whence I judged there to be another inlet or a strait between it and Cape Jervis. Soon after dusk the wind veered to south-by-east, on which we steered south-westward, and continued the same course until four in the morning [THURSDAY 25 MARCH 1802]; when the largest Althorp Isle being seen to the north-west, the ship was hove to, with her head eastward; and at daylight, before making sail, the following bearings were taken of the lands to the northward, but no part of Kangaroo Island was visible.
Wedge I. (of Gambier's Isles), highest part, N. 64½° W.
Althorpe Isle, largest, distant 6 miles, N. 83° to 78 W.
Cape Spencer, south point, N. 44 W.
Furthest extreme of the northern land, N. 44 E.
The wind fixed itself at south-east, and it took us two days to work back against it as far as Troubridge Hill [SATURDAY 27 MARCH 1802]. The shore is generally low and sandy; but with the exception of one very low point, it may be approached within two miles. Many tacks were made in these two days from the northern land across to Kangaroo Island, and gave opportunities of sounding the intermediate strait. From 45 fathoms, in the middle of the western entrance, the depth diminished quickly to 25, then more slowly to 20 after which it is irregular between 12 and 20 fathoms, as far as the mouth of the second inlet. Of the two sides, that of Kangaroo Island is much the deepest; but there is no danger in any part to prevent a ship passing through the strait with perfect confidence, and the average width is twenty-three miles. It was named INVESTIGATOR'S STRAIT, after the ship. The bottom is mostly broken shells, mixed with sand, gravel or coral, and appeared to hold well.
From two amplitudes taken to the north-north-west of Point Marsden, and near the middle of the strait, the variation was 1° 49' east; the ship's head being south-south-east in one case, and north-east-by-north in the other. The true variation deduced from these, is 3° 20' east; which is 1° 7' greater than at Cape Spencer, and 0° 53' less than at the anchorage near Kangaroo Head.
At noon of the 27th, the eastern wind died away; and we dropped a kedge anchor in 15 fathoms, about two miles from Point Marsden, where the following observations and bearings were taken.
Latitude, observed to the north, 35° 31' 38"
Longitude by time keepers, 137 42
Kangaroo I., furthest western extreme, S. 82 W.
do., Point Marsden, west side, S. 26 W.
do., innermost head up Nepean Bay, S. 27 E.
do., furthest eastern extreme, S. 57½ E.
Cape Jervis, south extreme, S. 73 E.
No set of tide was observable until three o'clock, when it made gently to the north-east, towards the new inlet; and a breeze springing up at south-east soon afterward, we pursued the same course, and were well within the entrance at eight o'clock. Fires were seen ahead; but the soundings being regular, and increasing, we kept on until midnight; when the land was seen also, and we stood back for two hours. At daylight [SUNDAY 28 MARCH 1802] I recognised Mount Lofty, upon the highest part of the ridge of mountains which, from Cape Jervis, extends northward behind the eastern shore of the inlet. The nearest part of the coast was distant three leagues, mostly low, and composed of sand and rock, with a few small trees scattered over it; but at a few miles inland, where the back mountains rise, the country was well clothed with forest timber, and had a fertile appearance. The fires bespoke this to be a part of the continent.
Light airs and calms prevailed during the morning, and the ship had very little way until noon, when a breeze sprung up at south-west. Our situation was then in