TRACT 3.

ON LONDON BRIDGE.

121

points above the surface of the river at low-water, and like-wise at every quarter of an hour before and after low-water ;and to observe the time when the low-water happens at thoseplaces; and the same for high-water.

“ 3. To take the height of the fixed point on the west sideof London bridge, above the surface of the river, at the lowstill water, and high still water under the drawbridge, withthe time of each.

“ 4 . To take the height of the same point, above the sur-face of the river, just above the sterling, at the time of low-water below bridge.

“ 5. To take the depth of the water in all the gullets, orat least in that under the drawbridge, at the time of low stillwater.

“ 6 . To ascertain in how many of the arches the dripshotpiles are driven ; how close together; and how far the topsof them are below low still water mark.

“ 7. To know particularly at what time the sterlings arefirst intirely covered, and when first intirely uncovered.

“ 8. To know exactly the time of low and high watermark, and the height the water rises to, at the Nore, Graves-end, and Woolwich.

“ 9. That all the foregoing observations of the tides, bemade at some one spring tide, and likewise at some one neaptime. Was signed,

M.Folkes; Wm. Jones; Jas. .Turin; Geo. L. Scott; Benj..Robins; John Ellicott.”