MR. LUBBOCK ON THE TIDES. 
103 
regarded the masonry and starlings, although the section of the river was far from 
completed, many portions still remaining one or two feet above low-water mark, and 
which were finally removed in the year 1834*.” 
The time of high water appears now to be nearly as late as in 1804; in 1821 it 
was about ten minutes sooner. 
I am much indebted to Mr. Yates for notice of a very ancient tide table which 
exists in a MS. in the British Museum. It is in the Codex Cottonianus, Julius DVII., 
which appears to have been written in the 13th century, and to have belonged to 
St. Albans Abbey. It contains calendar and other astronomical or geographical 
matters, some of which are the productions of John Wallingford, who died Abbot 
of St. Albans a.d. 1213. At p. 45 b. is a table on one leaf, showing the time of high 
water at London Bridge, “ flod at london brigge”, thus : 
N.B. The numbers increase by a constant difference 
of forty-eight minutes. The first coiumn gives the 
moon’s age in days. 
Hence it would appear that high water at London on full and change was at that 
epoch 3 h 48 m , or more than an hour later than at present. The time of high water 
at London on full and change is given in Mr. Riddle’s Navigation and in other 
works 2 h 45 m : Flamsteed made it 3 lu |''. 
.dStas 
Lunae. 
h 
m 
1 
3 
48 
2 
4 
36 
3 
5 
24 
4 
6 
12 
28 
’ 1 
24 
29 
2 
12 
30 
3 
0 
Note. — On the Fluctuations of the Height of High Water due to changes in the Atmo- 
spheric Pressure. 
Read June 15. 
M. Daussy having ascertained that at Brest the ocean rises when the barometer 
is depressed, I verified the existence of the same fact at Liverpool and London, and 
I found that at Liverpool when the barometer falls ‘91 inch the tide rises 10T inches. 
As the range of the barometer is 3 inches^:, the correction which arises from change 
in the atmospheric pressure is by no means inconsiderable, its range being at Liver- 
pool about 33 inches. At London I have found that when the barometer falls ’9 inch 
* Rennie, Report on Hydraulics, p. 512. f See Philosophical Transactions, vol. xii. p. 12. 
+ Between the tropics the fluctuations of the barometer do not much exceed one fourth of an inch, while 
beyond this space they reach to 3 inches. Daniell’s Meteorological Essays, p. 108. 
