THE SMITHSONIAN INSTITUTION. 241 



THE REGISTER. 



In the register the first page is devoted to regular observations; the 

 second to additional observations, to periodical or extraordinary phe- 

 nomena, and to monthly recapitulations. The headings of the columns 

 indicate clearly the use of each. 



For each instrument the columns follow each other in the order in 

 which the observations are to be made, and one column is reserved to 

 enter the observation y?<s^ as it is made, and before any correction or re- 

 duction. As each sheet is to be regarded as an independent docu- 

 ment, it should carry with it all that is necessary to correct the obser- 

 vations therein contained, and to render them authentic. Thus, the 

 date of the year, the month, the precise locality, the latitude and 

 longitude, the elevation of the instruments from the ground and above 

 the sea^ the nature and condition of the instruments which have been 

 employed, and the amount of their corrections; finally, the signature 

 of the observer, should be repeated on every leaf. It will be sufficient, 

 for this, to fill the blank spaces left after the different printed titles 

 in the blank forms. The observer should the less neglect this im- 

 portant duty, as it is an affair of only a few strokes of the pen each 

 month, without which his labor would run the hazard of losing its 

 value. 



Thermometer. — In the thermometrical observations the quantities 

 above zero will be always written without a sign ; the negative 

 quantities will be all individually marked with the sign minus, ( — ,) 

 whether they follow each other or are isolated. In the first column, 

 entitled daily inean, will be inscribed the mean of the three observa- 

 tions of the day, i. e. their sum divided by 3, admitting two decimals. 

 In the second column of the daily mean will be inscribed the mean of 

 the maximum and the minimum, given by the thermometrograph, 

 or self-registering thermometers. 



Barometer. — The degree of the attached tliermometer and the ob- 

 served height of the barometer will be inscribed in the first two col- 

 ums. This height will be reduced to freezing-point, or 32° Fahrenheit, 

 or zero Centigrade, by means of the annexed tables, and the whole 

 correction of the instrument, indicated on the back of the sheet, will 

 be applied to it. It will then be inscribed in the third column, en- 

 titled corrected height at freezing-point. These corrected heights, and 

 never any others, must be employed to form the mean, which Avill be 

 inscribed in the fourth column. 



Psychrometer. — In the first two columns will be entered the indica- 

 tions of the dry and wet thermometer, after having applied to each 

 of them the correction of the instruments, if there be any ; and in 

 the third column the difierence of the two numbers. By means of 

 the psychromctrical tables will be found the force of the vapor anik the 

 degree of relative moisture, each of which has its column, as well as 

 the daily means of each of these elements. 



We have indicated above the manner of noting the direction of the 

 winds. 



As to the force of the surface wind, which alone can be estimated 

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