Page:A Voyage to Terra Australis Volume 1.djvu/370

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wood at such times as the pits might require to be left for replenishing.

The necessary duties being all set forward under the superintendance of proper officers, I employed the following days in surveying and sounding. The direction of the port was too remote from the meridian to obtain a base line from differences of latitude, which, when observed in an artificial horizon, and at stations wide apart, I consider to be the best; nor was there any convenient beach or open place where a base line could be measured. It was therefore attempted in the following manner: Having left orders onboard the ship to fire three guns at given times, I went to the south-east end of Boston Island, with a pendulum made to swing half seconds. It was a musket ball slung with twine, and measured 9,8 inches, from the fixed end of the twine to the centre of the ball. From the instant that the flash of the first gun was perceived, to the time of hearing the report, I counted eighty-five vibrations of the pendulum, and the same with two succeeding guns; whence the length of the base was deduced to be 8,01 geographic miles. A principal station in the survey of Port Lincoln was a hill on the north side, called Northside Hill, which afforded a view extending to Sleaford Mere and Bay, and as far as Cape Wiles on one side, and to the hills at the