Mill has shown that in the North Sea off the Firth of Forth the average depth of visibility of a disk in the winter half-year was 4; fathoms and in the summer half-year 62 fathoms, and, although the greater frequency of rough weather in winter might tend to obscure the effect, individual observations made it plain that the angle of the sun was the main factor in increasing the depth to which the disk remained visible.
But Forbin was chased away from the Firth of Forth by a fleet under Sir George Byng; he refused to allow the young adventurer to land farther north, and the Jacobites doubted that France was never serious in the enterprise.
Indeed, Thames whitebait which have been compared with that from the mouth of the Exe, the Cornish coast, Menai Strait, and the Firth of Forth seemed to be better fed; but, of course, the specific characteristics of the herring and sprat - into which we need not enter here - were nowise modified.
Towards the north the site of the city slopes gently to the Firth of Forth and the port of Leith; while to the south, Liberton Hill, Blackford Hill, Braid Hills and Craiglockhart Hills roughly mark the city bounds, as Corstorphine Hill and the Water of Leith do the western limits.
The central public baths in Infirmary Street, with branch establishments in other parts of the town, including Portobello, are largely resorted to, and the proximity of the Firth of Forth induces the keener swimmers to visit Granton every morning.
Four instances have, however, been recorded of its occurrence on the British coasts, one on the coast of Norfolk in 1588, one in the Firth of Forth in 1648, one near Boston in Lincolnshire in 1800, while a fourth entangled itself among rocks in the Sound of Weesdale, Shetland, in September 1808.
The thin seams of the Calciferous Sandstone are not workable, but the bituminous shales in the Firth of Forth basin are largely worked for the manufacture of mineral oil.