4 
ME. T. Gr. BUNT’S DISCUSSION OF TIDE OBSEEYATIONS AT BRISTOL. 
another. Their mean parallaxes and declinations, according to the Nautical Almanac 
for 1866, became as follows: — 
O’s Decl. 
O’s H. Par. 
June 8 . 
. 22 51 
8-45 
June 23 . . 
. 23 26 
8-44 
Mean . 
. 23 8 
8-445 
Dec. 8 . . 
. 22 44 
8-71 
Dec. 23 . . 
. 23 27 
8-72 
Mean . 
. 23 5 
8-715 
Here we have a difference of 0"-27 of parallax* with only 0° 3' of declination. 
From these pairs of curves are obtained the solar parallax curves in Plate II. fig. 4. 
In like manner, by combining eight curves in two sets of four curves in each, we obtain 
the following means: — 
O’s Decl. Q’s H. Par. 
March 23 . . 1 34 8-60 
April 8 . . 7 14 8-56 
Sept. 23 . . 0 5 8-555 
Oct. 8 . . 5 54 8-59 
Mean (from squares of the declinations) 4 40 8 - 576 
June 8 . . . 22 51 8-45 
June 23 . . . 23 26 8-44 
Dec. 8 . . . 22 44 8-71 
Dec. 23 . .23 27 8-72 
Mean . . 23~^T 8418 
Here the mean declinations are 4° 40', 23° 7'; while the parallaxes differ only 0"-004. 
These give the solar declination curves in Plate II. fig. 5. 
During the remarkably fine weather of the summer of 1865, I found the curves 
drawn by the pencil of the tide-gauge on the sheet of paper wrapped round the cylinder, 
more symmetrical and regular, and the agreement of the registered times of high water 
with those predicted in my tide-table closer than I had ever known them before. The 
mean error of the predicted times (found, not algebraically, by taking the balance of 
those + and those — , but by adding all the magnitudes together, regardless of signs) 
was from the 10th of April to the 24th of October only 2^ minutes ; and during about 
six weeks, namely, from the 17th of August to the 27th of September, it was less than 
1-9 minute per tide. 
The diagram No. 4 shows the whole of these six months’ times and heights of high 
water, both as predicted and registered ; and is interesting chiefly because it so clearly 
exhibits the two Diurnal Inequalities. No one who looks at it can fail to detect, in an 
