512 
the tide was nine feet. I knew, from the tidal observations of the Aca- 
demy, of which I had the custody, that both these statements were er- 
roneous; and, as they both seemed to be considered of importance in the 
trial, I resolved to make the measurements requisite to ascertain the truth 
with precision. I have never yet made the results I arrived at public, 
as they did not affect the result of the trial, for a reason which will be 
stated; and I now bring them before the Academy as an illustration of 
the importance of the tidal observations made by that body, and to show 
the valuable uses to which those observations may be applied. In bring- 
ing forward this subject, I have no wish to accuse those who conducted 
the prosecution of any negligence in procuring the best scientific infor- 
mation available, nor to express any opinion as to the course adopted 
by the Lord Lieutenant, in commuting Mr. Kirwan’s sentence, after his 
conviction for the murder of his wife. 
On the 18th December, 1852, low water occurred exactly at 10 4. um. 
(Dublin time), at Ireland’s Eye; and on the same morning, by simulta- 
neous observations on the tide-gauge at Kingstown, it was found to occur 
there at 9" 53™, showing that the tide at Ireland’s Eye is seven minutes 
later than that at Kingstown. By careful levellings made forwards and 
backwards by Professor Downing, it was found that the top of the ‘‘ Body 
Rock’”’ was 1:26 feet higher than the zero of the tide-pole used on the 
18th December. The following table contains the quarter-hour obser-~ 
vations made on this occasion at Ireland’s Eye and Kingstown :— 
Height of Height of 
Hour. Tide at Ire- |Tideat Kings-| Difference. 
land’s Eye. town. 
9-0 A.m.| 0°60 ft. 6:25 ft. 5°65 ft. 
915 ,, 0-43 ,, 6:00 ,, 5°57 4 
9°30 ,, 0:21 ,, 582 ,, 5°61 ,, 
9°45 ,, | 0-20 ,, 5°85 ,, B65 55 
100 ~,, 0°20 ,, 5°75 5, 5°55 ,, 
10°15 ,, | 0-18 ,, 5°80 5, 5°62 4, 
10°30 ,, 0-21 ,, 5°85 ,, 5°64 ,, 
10°45 ,, | 0-44 ,, 5:95 ,, B51 ,, 
11:0 ,, | 0°56,, 6:20 ,, 5:64 ,, 
5°60 ft. 
The interval from high water at Kingstown to that at Ireland’s Kye 
being thus found to be seven minutes, and the zero of the tide-gauge at 
Kingstown being ascertained to be 5-604 feet below the zero of the tide- 
pole at Ireland’s Eye, we have, since the top of the “‘ Body Rock”? i is 
1: 26 feet above the zero of the tide-pole, the following result :— 
Feet. 
Height of zero of the tide-pole above zero of gauge, . 5°604- 
Height of ‘‘ Body Rock” above zero of pole, . . . 1°260 
Height of ‘‘ Body Rock” above the zero of the etal ‘\ 6-864 
town tide-gauge, 
