328 Davis's Report on the Nautical Almanac. 
in France and Great Britain for the principal part of our knowl 
edge of these interesting and important phenomena, The tide 
tables of the American Statistical Almanac and Repository, as 
well as those of the numerous other popular Almanacs published 
in this country, which consist almost exclusively of the times of 
high and low water only, are derived directly from the tide table 
of the British Almanac, computed, of course, without any refer- 
elice to Our own coast and its peculiarities. It is another of the 
improvements proposed. in the American Nautical Almanac, to 
remedy this disadvantage, the nature of which may not be un- 
derstood. without a word of explanation. 
The subject of the tides is an astronomical problem... To trace 
out the astronomical laws of these phenomena, that is, their dis- 
tinct dependence on the san and moon and on the places of these 
luminaries absolutely, or relatively to each other, and also on the 
changes in the moon’s distance from the earth, required the study 
and comparison of the actual phenomena of the tides noted with- 
out interruption, aud for along period, at some particular port. 
This was first effectnally undertaken by La Place, who made 
use of a long series of observations at the port of Brest, by 
of prediction mych can only be derived from the full discussion 
continuous local observations. To stimulate 
tious at the dry docks in London, (institated for purposes of con- 
. Struction and improvement) running through nineteen years, th 
period of the Metonie cycle. He afterwards took up the tides at 
Liverpool, and accomplished there what he had previously done 
for London. Portsmouth, Plymouth, and other places were sub- 
Sequently treated to some extent ina similar way. T 
is the present tide table in the British Nautical Almanac, from 
which we are in the habit of taking the tide tables for the Ameti- 
eau coast, in our common annual publications, by simple ait 
ences. One book alone in the country pretends to preaiche 
and that of the times and heights merely of those remarkable 
SS te ES 
