440 
MR. .DAILY’S DESCRIPTION OF A NEW BAROMETER. 
“ base of the columns, at the north abutment of the bridge, and on the eastern side ; 
“ which is about five feet above the lowest platform, or landing, at the stairs. 
“ I have ascertained, by levelling from this spot, or bench-mark, to the floor of the 
“ Council room, in which the barometer was kept in June 1826, that the floor in the 
“centre of the doorway between the two rooms is 62 - 41 feet above the said bench- 
“ mark. The mercury, in the basin of the barometer, I found above the floor 2 - 84 
“ feet; making the rise from the bench-mark to the mercury 65’25 feet. 
“ I am, Gentlemen, your obedient humble Servant, 
“ B. Be van.” 
Upon what authority it was presumed that the present position of the cistern of the 
barometer is ninety-five feet above the mean level of the sea, (or, in other words, that 
the above-mentioned station at Waterloo Bridge is 1 1 feet 9^ inches above that level) 
I have not been able to ascertain ; since Captain Lloyd’s levelling of the river Thames, 
from Sheerness upwards, as detailed in the Philosophical Transactions for 1831, ter- 
minated at London Bridge. He says, page 190, “I concluded my levellings at a 
“ standard mark sunk in the large plinth of the landing place (near the wall) of the 
“ stairs on the north-east side of the New London Bridge. This standard was 2’3967 
“ [feet] below the north standard mark at Sheerness.” Now, as the north standard 
mark at Sheerness was ascertained by Captain Lloyd to be 1 3* 1 5 1 1 feet above the 
mean level of the sea, we consequently have the surface of the above-mentioned 
plinth at London Bridge equal to 10’7544 (or lOf) feet above the mean level of 
the sea. It therefore only remained to ascertain the difference of level between the 
surface of this plinth, and the surface of the plinth at Waterloo Bridge. 
But a doubt for a long time remained as to the position of the mark at London 
Bridge, since (as in the case of that at Waterloo Bridge) it had escaped the search 
of all those who attempted to discover it. It was at length found by Dr. Fitton, who 
in a note to his paper “ On the Strata below the Chalk,” inserted in vol. iv. (second 
series) of the Transactions of the Geological Society, page 370, gives the following ac- 
curate and circumstantial description of its position. “The mark here referred to is 
“ a flat piece of brass, let into a cavity in one of the two large flags, or slabs of gra- 
“ nite, which form the landing place at the bottom of the second flight of steps, de- 
“ scending from the footway on the north-east side of the bridge. The upper flight 
“ consists of 29 steps ; the second (at the foot of which is the mark) of 26. The 
“ lowest flight is more or less commonly covered by the water. The cavity, in which 
“ the mark is lodged, is about 3 inches square, with rounded angles ; and is two feet 
“ from the eastern wall, or side of the bridge, and two feet eight inches from the 
“ southern side of the stone. The surface of the brass is about half an inch beneath 
“ that of the stone, which is itself a few inches below the level of the water at high 
“ spring tides.” 
The propriety of such a position for a standard mark may be much questioned, 
since we know, from what has recently taken place at Blackfriars Bridge, that the 
