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