The sun. [volume] (New York [N.Y.]) 1833-1916, 1896-04-12
SOM ETER RATING.
Delicacy or Hearing that Can Detect .
Difference Off Tenth OF n Second.

Deitcacy OF Hearing that Snu Detcct q
Difference of n Tenth OF n Second.
There is a nautical instrument shop near the
East River where nearly all the chronometers
of vessels striking this port are left to be regu-
lated. or rated, to use the sailorman's technical
term. The shop is a resort for sea Captains, and
is known the world over. The sailors call it
"Ncgus's." and it is run by T.. S. & J. ID. Negus.
AT 40 Water street.
Every large vessel sailing the ocean has at
least two thermometers. and all the liners carry
at least three. and many of them carry four.
A chronometer Is never set, no matter how
much away from the true Greenwich time it
may be. except when it ID cleaned, and that is
only once in about three years. 1t is rated in
stead. When the Captain comes into port he
straightway takes his chronometer to the shop.
A record is made OF the time it registers. and it
is compared with the true time at Greenwich,
England. 1t may he kept in the shop for two or
three DAYS. or even in some cases a month. A
careful record Is kept to determine whether The
c~hronometer is gaining or losing time.
The average OF NJ! the observations gives q very
accurate estimate of what may be expected OF
the c~hronometer at sea. such is the skill of the
chronOmcter man that he can tell its variations
down TO the tenth OF a second. large clock In
the shop tick twice every second. Taking the
C~GToHometer to the big clock. the operator
listens ~intently to the ticking Of the big clock
mentally notes the difference. His ear is more
accurate than any, Instrument that can be made.
y CHTpuOuittbT WHICH neither gains III ipStS
is something that has never been built. At
mospheric and other variable conditions affect
1t. so that the feat is impossible. IL is this &C:
accuracy OF the ear that is the stock in trade OF
the chronOmetcr rater that cannot be patented.
copyrighted. nor initiated. II comes through
long practice only. When the job is done and
the Captain calls for his chronometer he re-
ceivcS an exact record OF what has been OBJ
served. A record {. as well kept in the shop.
No two OF the thermometers on board IA ship
may point to the same time of day, They may
vary several hours. in fact. But the Captain
knows inst how far away from the true time
each one is, from the ratings. and thus makes
his calculations. II his chronometer is five
minutes fast and points to half past >. he knows
that the actual time is 25 minutes past 2. But
the actual time is not what he cares for. 1t is
the elapsed time since he sailed. That is what
the chronometer is used to tell. Any old clock
will tell. the actual time near enough for all
practical purposes.
Another odd feature OF a chronometer is that
n dial On its face shows exactly how long IL has
been wound up. Chronometers are wound as
regularly as "A farmer milks his COWS. They will
twenty-tour hours. This is the kind most in
use. some thermometers will run eight days,
but they cost about $500, and are not much
used. The common kind costs about $3.50. In
tho NcGuseS' shop are constantly about 500
chronometers being rated. They are wound ut
the same hour. and thers IL more or less hust-
ling in the place about that time by ali hands.
II is no small job TO wind up 500 chronOmeters
every day; aud 1t is II considerable part OF the
1t will be seen that. as the records are pre-
served in the shop. when once a captain goes
keep on going there all the time. This makes
\egus's a great resort for sea Captains. Men
go in there every day who have been calling
there for many years, every time they are In
port. Strange adventures. odd experiences. and
novel tales are related there. The rating done,
the Captain takes his Instrument. passes out,
years. When he returns he may have tales to
tell about the Chinese, the Malay pirates, or the
talk ing to may reply to his odd tales with a re-
cital of experiences in the Arctic regions.