ON THE PHENOMENA OF STATIONARY TIDES IN THE ENGLISH CHANNEL. 71 



where I = sun's longitude, 1 



l=±n X 59'T37, 

 n = number of days from Equinox. 

 A = 23° 28'. 



Second Report of the Committee, consisting of Professor Sir 

 William Thomson, Dr. Merrifield, Professor Osboene Eetnolds, 

 Captain Douglas Gtalton, and Mr. J. N. Shoolbred {Secretary), 

 appointed for the purpose of obtaining information respecting 

 the Phenomena of the Stationary Tides in the English Channel 

 and, in the North Sea ; and of representing to the Government of 

 Portugal and the Governor of Madeira that, in the opinion of 

 the British Association, Tided Observations at Madeira or other 

 islands in the North Atlantic Ocean would be very valuable, 

 with the view to the advancement of our knowledge of the Tides 

 in the Atlantic Ocean. 



[Plates II.— VIII.] 



This Committee was appointed at the Plymouth meeting in 1877, to 

 endeavour to arrange for, and to collect the results of a series of 

 simultaneous tidal observations in the English Channel and in the North 

 Sea : and also to impress upon the Portuguese Government the advan- 

 tage which would accrue from the establishment of a station at Madeira 

 for systematic and continuous tidal observations. 



The Portuguese Government, having had this latter subject brought 

 under their notice by Her Majesty's Foreign Office, readily fell in with 

 the suggestion of the British Association ; and a self-registering tide- 

 gauge on Sir William Thomson's principle has been made by Messrs. 

 White, of Glasgow. This instrument has been sent out to Madeira, for 

 erection on the Loo Rock, in the Bay of Funchal, where it is hoped that 

 it will soon be working satisfactorily. The entire cost of construction 

 and of erection has been borne by the Portuguese Government, and the 

 instrument remains, of course, in their hands. 



The importance of an accurate knowledge of the tides at Dover in 

 particular, in connection with those of the entire English Channel, being 

 soon made evident to the Committee, as well as the great advantage 

 which would ensue from the establishment of a self-registering tide-gauge 

 at that place, the matter was brought by the Chairman under the notice 

 of the Board of Trade ; the request being further supported by the Lord 

 Warden of the Cinque Ports, Earl Granville. The Board of Trade 

 received the request most favourably, and consented to establish at their 

 own expense a self-registering gauge, at a site some distance down the 

 Admiralty Pier, where a tide-well had been made during the original 

 construction of the pier ; its connection with the water outside being at 

 a level of twelve feet below the low water of ordinary spring tides. The 

 gauge, embracing Sir William Thomson's latest improvements, has been 

 -constructed and erected by Messrs. A. Lege & Co., of London, under the 



1 It was found better, in practice, to take the sun's declination from day to day 

 from the ' Nautical Almanac,' by which means the eccentricity of the earth's orbit 

 was introduced. 



