The two vessels were always in company; and the general practice was to sail on parallel lines distant from each other from one mile to one mile and a half by day, and closing at night to half a mile, or as much less as the state of the weather rendered necessary. During the few hours of darkness experienced on the north of Ireland at that season of the year, the vessels were hove to, that no part of the suspected ground might be passed unseen, and the leads were kept going both day and night, from the depth of an hundred and fifty to two hundred fathoms. Their distances from each other were determined every hour by the angle of elevation subtended by their respective masts, at the heads of which balls had been placed to facilitate the measurement. Their mutual bearings were taken at the same time; and men were kept constantly at the mast-heads during the day, and a vigilant look-out preserved through the night.
The parallel of latitude of Tory Island, as already mentioned, was first carefully examined to the westward of all the positions of the rock, and then traversed back again. These runs were laid down on the chart, and then other lines traced, until the whole space was explored as there exhibited. And this system of crossing and recrossing over every part of the suspected ground was persevered in until the 31st of August; when having visited every position assigned to this danger, and indeed the whole space comprehended by them, without seeing any rock, or discovering any detached bank, which could indicate its having existed, the search was relinquished, and the vessels returned to England.
In addition to the system of cruising above mentioned, the hydrographer, in his instructions, had recommended that the vessels should sweep for the rock by laying out a large scope of hawsers between them, and drifting with it over the suspected ground. To effect this he suggested two methods. The one, when the two vessels should be on the same tack, the leading brig keeping a little off the wind, with her main-topsail occasionally lifting; the hawsers fast to her quarter, with a spring to them from her weather-bow; the sternmost brig lying to, with her main-topsail to the mast, the hawsers from her weather-bow, and a spring to them from her weather-quarter. The other method he proposed was that of drifting on opposite tacks, the hawsers fastened to their sterns, with springs to them from the weather-bow of each vessel.
An additional number of hawsers were accordingly provided for the purpose at Portsmouth; and, upon the principles described, a line of them, amounting to more than fourteen hundred yards, was laid out, and a large portion of the suspected ground subjected to this mode of examination. To prevent the central part of this long scope from descending to too great a depth, and to relieve the vessels and hawsers as much as possible from the strain
