New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1898-12-09
THE TIDES.
THE MOONS INFLUENCE AND ORIGIN

THE TIDES AND KINDRED PHENOMENA =;
ures Delivered in 1897 at the Lowell Institute,
Boston, by George Howard Darwin, Professor
and Fellow in the University of Cambridge.
Octave. Up. 37s. Houghon. Mifiiin & Co
II one were disposed to he hypercritical. he
might find some fault with tho arrang enent Of
the matter in this book One is puzzled b. find
Ing a chapter "Seichcs" the minor oscilIa-
lions in the level Of lakes. ahead OF tie account
Of genuine tides; and it seems trihe illogca! to
describe the bore-a tidal that often
ascends river with startling cons sequences -
before mentioning and explaining the rise and
fall Of the from which the bore proceefs.
But with regard 70 the principles involved. the
conclusions reached and the mathematics and
history Of the subject. there can be no reason
able complaint. Professor Darwin ranks one
Of the first living authorities in this department
OF science. The volume Under consideration
therefore Will be accepted a standard work
OF reference
The navgators Of the Mediterranean. so long
they kept inside the pillars Of Hercules. had
little opportunity 10 discover the semi-diurnal
fluctuations in the height OF the sea- but as soon
as they went out into the Atlantic they quickly
became familiar with the phenomenon. Posi-
donious. the Greek philosopher writing more
of the tides. as observed at Cadiz. And he noted
that they higher whenever the moon and
sun in a straight line with the earth than
at the intervening stages OF the lunar month.
IT is not unlikely. though. that the Chinese. who
sailed the Pacific long before this. and who must
have experienced the same tidal invasions Of
their rivers that now witnessed there twice
q day. recognized the existence OF tides thou
sands OF years before the Christian era That
the upft Of water was due TO the attraction OF
the moon was first asserted by the great dis
coverer OF the law Of gravitaticn. Laplace went
q step further and pointed out that the earth s
rotation an important factor in the prob
lem. Since the time OF that eminent French
mathematician the elder Sir John Lubbock
Whewell. Airy and Lord Kelvin have contributed
largely TO the worlds store of knowledge on this
subject. Lord Kelvin was the author Of an
original and valuable method Of analyzing the
data OF tides at numerous places Of observation
and thus deducng the laws that underlie the
strange qualities in the tides themselves.
1t is an interesting IA t that for many years
in the last century the ar: of predicting the time
OF the tides a trade secret possessed by a
certain few In London. Liverpool and other
ports The system which these forecasters
proceeded was handed down from father to sor
as a valuaol heritage. In 1881 the elder Lub
book got hold OF the records Of tidal observa
lions at London for term Of nineteen years
observations that were notably accurate-ant
put them in the hands of skilled computer fol-
examination. There were many Inequalities In
the intervals between the tides. we'll ir
the height Of the latter And it desirable
to Identify the causes OF these In order TO render
easy the task OF future prediction Sir Johns
assistant wrought out Of the figures given &c
him tables showing the effect Of the moons
height above the horizon her distance from the
earth and the hour Of her passage across the
meridian. Thus he able TO construct fore
casts Of his own that were. in spite OF slight de-
fects. surprisingly accurate: and in a few years
the predictions thus made proved 10 be superior
20 those Issued by the monopoes. Since then
however, still further improvements have beer
made In these calculations owing to the intro