Davis’s Report on the Nautical Almanac. 329 
tides which occasionally do so much injury ; and in this instance, 
the first numbers of La Place deduced from the Brest observa- 
tions, form the basis of calculation. . 
But it will be readily perceived that if the results obtained by 
La Place on the east side of the channel are not applicable to the 
British shores and harbors, still less are those derived from ob- 
servations made on the east side of the Atlantic likely to repre- 
sent the real phenomena on the American coasts. It will not 
perhaps be irrelevant to cite a single case under the general prob- 
lem of the tides. In order to be able to give rules practically 
useful to the pilot, engineer and seaman, for applying to the ordi- 
hary tides, corrections depending on the moon’s varying istance 
and declination, it is necessary to know to what meridian passage, 
or southing of the moon the tide is due; or, what the distance is 
from the land of the general tide wave that causes the local tide 
which the observer is actually registering ; or, in fine, what is the 
age of the tide when it arrives at any particular part of our coast. 
This knowledge is the result of the careful stndy of a large num- 
ber of observations made at various points. The age of the tide 
at London differs from that at Key West; and that of Key West 
again from that of New York, or Hampton roads. 
ur exclusive dependence upon European authority for that 
knowledge of our coasts which no European authority can, from 
the nature of the case, supply, has been a disadvantage and a re- 
proach. Both the disadvantage and the reproach the American 
Nautical Almanac will help to remove by making use, as has 
been authorized to do, of the materials in the records of the coast 
survey, for furnishing a tide table founded on the actual observa- 
tions of tides in our own northern and southern harbors, and 
their subsequent reduction and discussion in the office of that in- 
stitution. f 
The coast survey has established several permanent stations, 
as at Boston, New York, Old Point Comfort and Key West, 
where a continuous series of observations is kept up for ascertain- 
ing the peculiar connections of the phenomena at each place, the 
constants of theoretical calculation, and the very important influ- 
ence of local peculiarities, such as geographical situation, winds, 
and barometric pressure. At numerous intermediate places, tem- 
porary stations have been erected, from the registers of which 
of the Nautical Almanac to lay them in a compendious form an- 
nually before the navigator, pilot and engineer, in the work to 
which they recur, more or less frequently, for other information 
needed in their professions. The British publications, as John- 
