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XI. On the Tides of the Arctic Seas. 
By the Bev. Samuel Haughton, M.B. Buhl., B.C.L. Oxon., F.R.S., 
Fellow of Trinity College, Bublin. 
Part IV. On.the Tides of Northumberland Sound, at the Northern Outlet of 
Wellington Channel. 
Received July 11, — Read November 19, 1874. 
These Tidal Observations were made on board H.M.S. ‘ Assistance,’ Captain Sir Edward 
Belcher, R.N., K.C.B., from 24th May to 6th July 1853, the exact position of the 
ship being 76° 52' N. lat. and 97° 00' W. long. Sir Leopold M‘Clintock kindly 
procured for me, from Sir Edward Belcher, a copy of the Observations; and in 
forwarding them to me writes thus: — Sir Edward Belcher wishes me to tell you 
how his Tidal Observations in 1853 were made. He says they did not depend upon 
the guess of any one, but resulted from machinery connected with the bottom, which 
moved a ratchet-wheel, each cog or inch of gauge ringing a bell ; and the rise and fall 
was not that of the ship, but of the whole floe in which she was fixed. This machinery 
is described in his narrative, ‘ The last of the Arctic Voyages,’ vol. i. p. 141. He further 
states that this rise was repeatedly verified by Theodolite Observations.” 
The following Table contains the Time and Height of High Water and Low Water, 
extracted from the original observations (which are forwarded with this paper) ; also 
the Diurnal Tide at High Water and Low Water, calculated from the heights by means 
of the formula 
Diurnal Tide— 
Z-J — 4^2 + 6Aj 
16 
4// 4 + 7 i s 
5 
( 1 )* 
which gives the fourth difference of the successive heights. 
* This expression for the Diurnal Tide is used and explained by Mr. Atry in his paper “ On the Tides of the 
Coasts of Ireland ” (Phil. Trans. 1845), and by the author in his paper “ On the Diurnal Tides of the Coasts 
of Ireland” (Trans. Royal Irish Academy, 1855). 
o 
U 
MDC'CCLXXV. 
