TRANSACTIONS OF THE SECTIONS. 57 



grapffer, on the tides of the world, which, like the Nautical Almanac, is a text-book 

 for the seamen of all nations, owes the truth of its principles, and g^eat increase of 

 its detailed facts, chiefly to I)r. WheweU, and, no doubt, he will cordially add sug- 

 gestions, if he concurs in the belief that more still should be done. 



In the central parts of the Pacific Ocean, and at numerous isohited points seldom 

 visited for expressly tidal objects, exact details about the tides are wanting; but 

 they are unlikely to be ascertained, except by a vessel employed specially for that 

 puroose. 



lide-gauges, natiiral if not artificial, at such selected places, away from continents 

 and near the deepest seas, should be watched adequately during a sufficient time, 

 in order that their residts, and a few comparative observations at known places, 

 might enable Dr. Whewell to put the finishing hand to his comprehensive works 

 on Tides, and to leave them completed for the general benefit of posterity. 



On the Distfibution of Fog around the British Isles. 

 By J. H. Gladstone, Ph.D., F.R.S. 

 Among the returns asked for ],y the Royal Commissioners on Lights, Buoys, and 

 Beacons, and embodied in the Appendix of their Report laid before Parliament 

 last session, was " The number of daj's in 1858 on which fogs were noted in the 

 meteorological register." This question was asked in respect to each lighthouse 

 or floating light in the United Kingdom. The author had gathered together the 

 information thus obtained, and had constructed tables of 200 different sites, geogra- 

 phically arranged, with the frequency of fog at them in the year mentioned. 100 

 of these sites are in England and Wales, 48 in Scotland, and 52 in Ireland. 

 The following conclusions were drawn fi-om the tabidated nimibers : — 

 1st. The average nmnber of days in 1858 on which fogs were noted in the dif- 

 ferent parts of the United Kingdom is : — 



On the coast. At sea. 



England and Wales 28 21 



Scotland 22 17 



Ireland 19 16 



General average 24 20 



2nd. The distribution of fog over different parts of a sea varies little, even though 

 it varies greatly on different parts of the adjoiaing coast. Between the River 

 Humber and the Straits of Dover there are 23 stations at sea which returned num- 

 bers ranging between 15 and 32, and nearly all included between 18 and 24 ; whUe 

 the stations on the coast returned numbers irregularly distributed between 7 and 

 45, and in one instance 81. There are indications that fogs are about equally fre- 

 quent in other parts of the sea surroimding England and Scotland, but only half 

 as numerous on the west of St. George's Channel. 



3rd. The frequency of fogs on the coast is in many places far less than on the 

 neighbouring sea. Thus, on the southern and eastern coasts of England there are 

 14 stations where less than 15 days were noted. Every one of these is a station 

 near the sea-level ; and among them are the sandbanks at the mouth of the 

 Thames, and the breakwaters. Promontories of low land are not very often visited 

 by fogs. 



4th. Two stations very near one another, but differing in their elevation above 

 the sea, often differ widely in the frequency of fog, the lower site having generally 

 the smaller niunber. Thus the station on the beach at Lowestoft gives 7 days, 

 while that on the cliflT gives 27. At North Shields, however, it is the reverse. 



5th. When the land rises to a considerable height, and is so situated that it 

 meets the south-westerly winds directly after they have traversed the ocean, a 

 fi-equent deposition of moisture is the result— either "fog" or "cloud." The high 

 points along the south and south-west coasts of England and Wales all give large 

 numbers, especially the Start, 79 days ; Needles, 75 ; St. Catherine's Point, 76 ■ 

 and Lundy Island (the highest station in England), 76.- The lighthouse at the 

 Needles has on this account been recently removed from the cliff to a low rock. 

 In Ireland, the greatest frequency of fog noted in 1858 was at Ballycotton, 55 days, 

 a high station on the southern coast. The west of Ireland appears not to be visited 

 by fog so often as the west of England. The greatest number in the whole list is 



