The new South-news., 1906-11-17
the SIZE OF OCEAN WAVES.


uSW ss'' s'ti-
A well known French naval cxprrt.
NJ. Berth, believes that both the
ienKsh and height o. waves az sea
nre often overestiratcd lie goes on
to argue that the length of waves
can be computed from the time which
clsrses between the passage of two OF
them. From summary Of his opin-
ions which Epgineerins prints q Ap-
pears that the greatest distance
which he has estimated between crest
and crest IL 25se feet, or about half
mile. aud the period on which his
reckoning was based WIS twenty
three seconds.
Such long waves, he states. are
never very high. In deep water the
height OF a wave half milo long viii
not. at most. he more than dity.two
feet. or onc-hftieth rs length. Much
greater heights than this have. DO
saws. been recorded. particularly from
small craft. bu, the observations were
/ ou,tc unreliable. The error arises
mainly from the fac, that the oh.
server has failed to take into account
the fact that the vessel ne is in floats
with its deck parallel 10 the surface
of the wave. and not TO true horl-
rontal plane. With the water sur
face thus tilted. grossly cAaererafed
estimates OF the true height OF the
waves become possible.
Where care has been taken IN
avoid this source Of error. the highest
wave recorded in open water has
measured forty-tvo and one-haif feet
from hollow to crest. but NJ. Bcrtin
believes that height Of nfty-two feet
may perhaps be met With in tho
southern seas. On entering shoal
water waves become higher and
shorter. so that a wave that has
height OF thirteen metres In OMEN
water may attain sixteen metres on
striking a shoal while ~ Il meets a
more or less vertical obstacle It may
shoot up to double this height. and at
the Eddystone Light. he states. solid
green seas have been known to reach
a height OF 1ob feet.
Waves half p mile long are. he
continues. very rare, rlnce period OF
ten seconds IL not often exceeded.
which corresponds to length OF 100
metres (about 52o fcet). More COM
monty the period is six to egh, sec
onds, and the length 1860 TO 32o foct.
Heights OF over ten metres tthirty-
three feet) are rare. but short waves
are relatively higher than long ones.
q wave 100 feet long being commonly
eight to sixteen feet high. NJ. Bertin
!. further points out that there appears
to be minimum TO the size OF ocean
. waves, a. well as maximum, since
there In Z connection between tho
, size and the velocity OF the wind pro-
ducing them. Thus waves measuring
three-fourths inch from crest TO crest
would correspond to a Wind moving
about two feet second and he ques-
tions whether Wind moving more
. slowly than this would have power
to raise waves at all
The Greatest Gem Mine In the World.
The sapphire workings at yogo
: Gulch. Mont. are being gradually
developed into q great and perma.
| nent mining industry. says Mr.. Geo
i. Kunz in a forthcoming report on
precious stones. published by the
United States Geological Survey
Taken as whole the Yogo dixie II
perhaps the greatest gem mine IN ths
: world II Is about four miles Ion,
on the surface, and being q true liz
neous dixie, descends to an indefinite
? depth II Is estimated that the en-
tire content OF workable sapphire
bearing rock would approximate 10,
100000 cubic yards. A mining plan
IS now being erected here which wi
quadruple the previous output an
make Montana sapphire mining
very important factor In America
: gem production.
The stones obtained are not
large size. They range from "cuns
used for watch jewels and other m
chanical purposes, to gems averagIr
when cut from half 4 carat 10 two ,
three carats aud rarely up to nve
six. Az gems they are brilliant, r.,
from fiawr and OF good color, ran
ing from light shades to the ric
deep blue OF Oriental sapphires. II
Yogo crystals have an advantage I,
mechanical uses over East Indis
stones In their form. which 10 large
short prismatic .rhom bob edral VII
nat basal terminations. and hen
they need much less cutting for "a,
purposes as watch jewels. The gen
are sent to Amsterdam for cutting.