ME. T. Gr. BUST’S DISCUSSION OB TIDE OBSEEYA TIONS AT BEISTOL. 5 
instant, the existence of them both; and the one is as manifest as the other. The 
agreement everywhere seen between the computed and observed Diurnal Inequalities, 
the laws of which it has cost me so much labour to attain, has, I confess, afforded me 
no small gratification. 
Accompanying this diagram, I have enclosed a sheet taken from the Cylinder of the 
Tide-Gauge, containing the original markings of the pencil, on which an ink line has 
been very carefully drawn. It registered some of the tides of the remarkably tranquil 
period which has been already referred to, and is sent as a specimen of the great regu- 
larity which the curves sometimes exhibit*. 
Postscript. 
Eeceived October 27, 1SG6. 
Barometric Inequality. 
In a letter of mine inserted in the Deport of the British Association in 1841, I stated 
that from a comparison of three or four years’ computed and observed Heights of High 
Water at Bristol, I had found that a fall of 1 inch in the mercurial column was accom- 
panied by an average rise of about 13^ inches of tide. I have since obtained for fourteen 
additional years the following proportions of tide and mercury : — 
1841. 
Tide. 
in. 
. . . 13-01 
1842. 
. . . 11-4 
1843. 
. . . 13-2 
1844. 
. . . 11-4 
1845. 
. . . 10-6 
1846. 
. . . 14-7 
1847. 
. . . 16-0 
1848. 
. . . 13-7 
1849. 
. . . 10-0 
1850. 
... 9-5 
1851. 
. . . 11-0 
1852. 
. . . 11-7 
1853. 
. . 12-0 
1854. 
. . . 12-0. 
> to 1 inch of mercury. 
14)170-2 
Mean . . 12-157 inches of tide to 1 inch of mercury. 
The mean of all the twenty-one years I have thus examined, viz. 1834 to 1854, is 
12-772 inches of tide to 1 inch of mercury. 
* It has not been deemed necessary to give a Plate of this Tide-Gauge Sheet, or of Diagram No. 4. The 
latter is, however, preserved in the Archives of the Society, accompanied by a detailed explanation. 
