PHILOSOPHICAL TRANSACTIONS. 
I. Discussion of Tide Observations at Bristol. By T. G. Bunt, Bristol. 
Communicated by the Astronomer Boyal. 
Received October 24, — Read December 6, 1866. 
This paper contains the result of an attempt to discover empirically the Laws of the 
Diurnal Inequality of the Times and Heights, and of the Solar Inequality of the Times 
of High Water at the Port of Bristol. 
The observations employed in this discussion are those that have been taken by the 
Bristol Self-registering Tide-Gauge, which has been kept steadily at work, with a few 
occasional interruptions, from the period of its erection in 1837 to the present time. 
This instrument consists essentially of a Clock, a Cylinder, a Float, and a Pencil, by 
means of which every tide marks a curve on a sheet of paper, from which the time and 
height of high water are ascertained. Its details are described, and an engraving of 
it given, both in the Philosophical Transactions for 1838, Part II., p. 249, and in the 
Article “Tides and Waves” in the Encyclopaedia Metropolitana, written by the present 
Astronomer Royal. 
During the far greater part of these twenty-nine years, the Tide-Gauge has been at 
work under my own continual inspection ; and it may be important to remark that the 
clock has, from the commencement, been carefully adjusted to Bristol mean time by 
transit observations : viz. during the first fourteen years by comparison with the Transit 
Clock of Messrs. Muston and Gath, chronometer makers in this city, besides frequent 
sextant altitudes of the sun taken by myself, and for the last fifteen years by a transit 
instrument in my own house. 
Soon after the Meeting in 1836 of the British Association in Bristol, I was employed 
under its auspices, in assisting the late Dr. Whewell in his discussions of the Bristol 
Tides ; the results of which appeared in a succession of papers in the Philosophical 
Transactions, extending from 1837 to 1840. 
The Diurnal Inequality of the Tides was that branch of the subject to which Dr. Whe- 
weli/s attention was specially directed. In explanation of this term, if any such be 
necessary, it may be stated briefly that successive tides do not increase or decrease by a 
MDCCCLXVII. B 
