INSTRUCTIONS TO MARINE METEOROLOGICAL OBSERVERS 31 



only one observation a day, at Greenwich mean noon. _ Also on 

 radio-reporting ships, when outside the areas from which daily 

 radio rej^orts are sent, the observations are entered only once each 

 day at Greenwich mean noon. On all ships cooperating with the 

 Weather Burean, by radio or mail, it is desired that appropriate 

 entries be made in the spaces for "Daily Journal" and also in the 

 spaces for "Gale or Storm", aiid "Fog" reports. 



The forms provide for 10 observations on each sheet. However, 

 it is requested that the observer begin a new record sheet upon cross- 

 ing from one ocean to another, and on the first of a new month. The 

 reason for this request is that the forms are filed at the Weather 

 Bureau in separate compartments for the oceans and months, hence 

 special compartments must be provided for forms which contain 

 observations for more than one ocean or more than one month. It 

 is also highly desirable that the forms be mailed at the end of a 

 voyage, even if a sheet is not filled ; a new sheet should be started at 

 the beginning of the next voyage. 



The various columns on Form 1210A are grouped in such a way 

 that all the so-called Universal Data will be recorded exactly in the 

 order specified by the International Kadio Weather Code. The col- 

 umns for these data are boxed off from the other columns on the 

 form by heavy black lines. However, in obtaining and entering the 

 data at the time of an observation the observer does not necessarily 

 proceed across the sheet from left to right. It is most natural to 

 enter simultaneously the data relating to the day, the hour, and the 

 ship's geographical position. The actual weather observations, like- 

 wise, are entered in a group. Therefore, in the following paragraphs 

 detailed instructions for the taking and recording of a complete 

 observation will be given as nearly as possible in the order usually 

 followed, and not strictly in order from left to right on the form. 



When a new form is begun the first step is to fill in the blank 

 spaces at the top of the sheet. This entails the entry of the vessel's 

 name, etc., and of details relating to the character of the instru- 

 mental equipment. 



Notes on instruments used. — The kind of barometer, whether 

 aneroid or mercurial, should be given, with the identification num- 

 ber furnished by the Weather Bureau. 



The same barometer should be employed continuously. If for any 

 reason it becomes necessary to use another instrument, the fact 

 should be stated, the reasons given, and the second instrument fully 

 described, in order that the readings of the latter may not be con- 

 fused with the readings of the barometer listed by the Weather 

 Bureau. 



The error of the barometer should be entered as determined by 

 the last comparison with a standard instrument; also the place and 

 date of this last comparison in the space provided. 



If it is a mercurial barometer, the scale of the attached ther- 

 mometer employed, whether I'ahrenheit, Centigrade, or Absolute, 

 should be stated. 



Space is provided at the top of the form for indicating how the 

 sea-surface temperature is measured. It is desirable to know this, 

 because the temperature of a sample of sea water obtained by means 



