eMac ceiccd aM A kk a a eS deElcallSt

indicated both by

of last
FF3 gives mean windspeed in knots over the past three hours (since the time
mparison immediately4 S otservation). The value shown was computed from the dial readings and was rounded off to the
thay

rv differed fram the } m

For a discussion of anemometer calibrations, see Notes for Table 3.

nearest whole knote

terms
LDFF gives wind direction to 8 points of the compass and windspeed in descriptive
Oo read 1° F. too low or in otse where descriptive terms or a range in knots is given, the windspeed was estimated

cordingly.

Thus the

Where a single windspeed value is given it represents speed to the nearest

E by the observer.

ted in the Tables,
«0 or e5de

Since the’ E

knot as determined from the anemometer dial readings at the beginning and ending of one minute,

Je 3?

since

unless some other time interval is specified in the Table.

F.

and

’ Beaufort phraseology.

F. (see Notes,

Descriptive terms follow the

Estimated amounts (covering a range of speeds) are correct within 20%

(see above);
of the extremes shown where estimates were made by experienced observers
wise, they are judged to be correct within 40%.

$s associated with

shere was no appreci-©

Times of beginning and end of rain are biased in the direction of giving too late a time
in many instances.

t Figures 13 and 14

In this a distinction must be made between daytime and nighttime values.

Daytime values are probably correct within 5 minutes.

Sion.

ris qualified by the f

Nighttime values may be in error by as

much as 30 minutes and there may well have been light showers that were not detected at night
(On behalf of the observer it must be stated that these

t estimate, indicates
F

since the observer was often asleepe

t N at these statione
§

were 24- or 48-hour watches, with the observer alone on the islet.)

ints, the accuracy

ey Biaati...

istances (see Notes

patbcd

A

1 10Cs, BRUCE and

other-

i

& been trained in

ervational period. HF

Times of occurrence of

phenomena other than beginning or end of rain are probably correct within 5 minutes.
however, a distinction must be made between daytime and nighttime:

Here also,

There may well have been

special phenomena that were not detected at night, not only because of poor visibility but also
because the observer was in his tent asleep.

TALLE 7e

BRUCE:

SPECIAL OBSERVATIONS.

Date and Time refer to 180th meridian.

Times are absolutely correct to within 5 minutes

rough training.

{allowing for error in setting of observer's watch) and are relatively correct (compared with

y Always correct

one another) within 1 minute.

- probably they

IT and Ty were measured with a psychron, the instrument being held into the wind with the

' and they probably a

bulb shielded.

tratus.

within 0.5° F,

Therefore

photographs, to

the following
2d observers,

Temperatures were estimated to the nearest tenth of a degree F. and are correct

Heights were estimated and are correct within 6 inches for the 5- and 3-foot
heights and
within 3 inches for the one-foot height.

Ts was measured with an unshielded thermometer, graduated in half-degrees Centigrade.

rals (all times

Headings were estimated to the nearest tenth degree C. and were converted
to the nearest tenth

(00 Aug 28 ~— 0900 J :

degree F.

The thermometer was held with the bulb continuously below the
water surface, at a

43

A a me oe
Ao WY. Te ee + sone mere

~, a i a

iatanefn eee we Se Leen mee
my

sadinesceencetetinieneet 2 ahaeadiatnet iia taten 7 atic ets
eee een
“ome
+

Pe

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