36 



llECORD AND DISCUSSION OF TEMPERATURES. 



above or below the mean temperature, + indicating } ^^' ^ I than the mean. 



These differences are herewith presented graphically by full lines; the phases of 

 the moon are marked opposite the corresponding dates, the new moons being given 

 at the top, the full moons at the bottom, of each diagram. The investigation com- 

 mences with Nov. 3d, and ends with April 13th, for the winter 1853-54, and in- 

 cludes the time between Oct. 19th and April 16th of the second winter. Between 

 these intervals, the mean half monthly temperatures are below — 10°. Tempera- 

 tures observed after Jan. 24th, 1855, have been taken from the abstract in Vol. II. 

 of the Narrative (corrected for index error). They are probably subject to small 

 corrections, and hence have been dotted in the diagram. 



The wavy line above the zero line indicates the number of hours during which 

 snow fell in the corresponding 6 day period ; the numbers in the vertical column 

 answering also for the hour scale. The wavy line below, or on the negative side 

 of the temperatures, indicates the number of clear days in each 6 day period, and 

 in order to use the side figures also for this day-scale, the number of clear days 

 was doubled, 12 being the maximum indication of 6 clear days. 



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