At Stirling, according to instructions, he examined the promontory to select for his observations a spot, which would be probably free from unequal attraction, and fix its position by triangulation. In this he was quite successful. The point was “so far to the east as to be out of the direct meridional line of attraction of the hills lying south of Cowhythe,” and by this series of observations it was ascertained, “that the deflection existing at Cowhythe, is not general in those latitudes, and that the discrepancy between its observed and calculated latitude, is not due to an error in the figure used in computing the geodetic result, but to local attraction affecting the astronomical latitude.”[60] The fact of local attraction was now fully established; but from some peculiarities of its influence in particular districts, the inference derivable from it is, notwithstanding the skilful conclusions of scientific men, that the figure of the earth is _different_ to the commonly-received opinion of its form. In these later services he and his party were alike exposed to dangers at sea, and to trials and privations on land; and besides encountering many perils in difficult boat service, and in landing on almost inaccessible coasts and islets, they were on several occasions nearly shipwrecked. A small party at Rona was subjected to severe hardships. Its number consisted of corporal Michael Hayes and ten civil labourers, who embarked with sergeant Steel’s party on the 29th of August, 1850, to survey the island. On the following day, by a desperate effort, the corporal and his labourers pushed into the boat, and taking with them a little provisions scrambled amid the surf on shore; but as the weather was boisterous, and there was no harbour or anchorage in which the schooner could lie-to, she was compelled to return that evening to Stornoway with sergeant Steel and the sector party. Several days were now spent in intrepid attempts to regain the island, but such was the roughness of the sea, and such the fury of the wind, that all efforts to do so proved fruitless; thereupon, the master of the vessel considering the undertaking to be impracticable threw up his contract, and it was not until the 7th of September, when another vessel had been engaged for the service, that Rona was approached, and a landing effected. All this time, seven days and eight nights, corporal Hayes and his party were pent up in Rona upon a very scanty allowance of food, and exposed without shelter of tent or hut, or even the comfort of warm clothing, to the cold and tempestuous storms of that dreary and desolate island. ----- Footnote 48: