[ 45 ] 
VI. On the Laws of Individual Tides at Southampton and at Ipswich. 
By G. B. Airy, Esq., M.A., F.R.S., Astronomer Royal. 
Received February 16, — Read March 2, 1843. 
With the view of verifying the reported peculiarity in the tides at Southampton, I 
had proposed in the month of February 1842 to proceed thither for the purpose of 
examining, with my own eyes, the rise and fall of the water during one or more tides. 
As soon, however, as my purpose was made known to Colonel Colby, R.E., Director 
of the Trigonometrical Survey, and to Lieutenant Yolland, R.E., the Resident 
Officer at the Ordnance Map Office, Southampton, I received from those gentlemen 
the offer of placing at my service, for these observations, non-commissioned officers 
and privates of the corps of Royal Sappers and Miners, as well as of preparing and 
fixing the vertical scale of feet and inches, and of keeping a watch upon the general 
accuracy of the observed times. I was extremely glad to avail myself of this offer, 
for I believe that a more intelligent and faithful body of men does not exist than the 
Sappers employed in the Trigonometrical Survey; and I knew well the advantage of 
employing, upon a tedious business like this, a set of regular-service men stationed 
on the spot. 
A vertical scale of deal laths, upon which the divisions and figures were branded, 
was fixed near the end of the pier at Southampton, very near to the landing-stairs on 
the north side of the pier, so that the divisions could at all stages of the tide (with 
the assistance of a lantern at night) be easily read by a person standing on the stairs. 
The order of the graduations of the scale was increasing from the bottom upwards, 
and the zero of the scale was found, by levelling, to bear the following relation to cer- 
tain fixed marks : — 
[The mark in each case, except that of St. Paul’s Church, is a horizontal cut, indi- 
cated by the point of an arrow. The arrow is on one side of the mark at Holyrood 
Church, and below each of the others.] 
The zero of the scale is, 
Below a mark cut on the metal of the coat of arms on the north side of the 
pedestal of Chamberlayne’s column, Watergate Quay 
Below the ground at the same place 21 -990 
Below a mark cut in the stone jamb on the south side of the centre door of 
Holyrood Church 
Below the floor of the portico 33-3/0 
} 
36-310 
1 
feet. 
25765 
