GEOLOGY. 



37 



Followiag is the monthly summary oi the meteorological observa- 

 tions : * 



United States t)bserving station, Kerguelen Island ; latitude, 49° 21' S. ; longitude, 70° 

 15' E. ; altitude of barometer above sea-level, 130 feet. 



Mouth. 



Barometer, mean. 



Thermometer, mean. 



Saturation, mean 

 percentage. 



"Wind, 

 mean 

 force. 



Eain, 

 total. 



September* . 

 October t 



November J.. 

 December § .. 



8 a. m. 

 29.60 

 29.36 

 29.73 

 29.53 



2 p.m. 

 29.52 

 29. 32 

 29.74 

 29.39 



8jp. m. 

 29.60 

 29.32 

 29.74 

 29.54 



8 a. m. 

 42.9 

 41.97 

 44.9 

 49.02 



2^. m. 

 46.00 

 41.6 

 50. 

 52.05 



8 p.m. 

 38.14 

 34.00 

 41.6 



43.2 



8 a.m. 



'Hp.m. 



8 p.m. 



8.1 

 5.6 

 5.3 

 6.45 



Inches. 



2 

 6.3 









.855 

 .83 



.792 



.77 



.823 



.84 



* Snow or rain, excepting two clear days. 

 t Four days without snow or rain. 



X Twelve days without snow or rain. 

 § Mne days without snow or rain. 



The barometer touched its highest point, 30.30 inches, on September 

 16 and Navember 17 j the wind being light on both occasions, from the 

 southward and westward, with rain on the latter date. On October 18, 

 the day after a severe gale, the barometer fell to 28.74, the forenoon 

 being clear with snow in the afternoon, and the wind from the south- 

 west. Again, on October 25, the wind being light, from the northwest, 

 with snow all day, the barometer fell to 28.72. This also was the day 

 after a severe gale. As a rule, we were disposed to place more reliance 

 upon the steadiness of the barometer as an indicator of good weather 

 than upon its actual height; fierce gales, snow, and rain occurring with 

 almost every position of the mercury, but generally preceded by either 

 a rapid rise or a rapid fall. From the 4th of December, for example, to 

 the 9th (the day of the transit), the barometer had fallen steadily but 

 very slowly from 29.92 to 29.12 j yet the morning of the 9th dawned 

 perfectly clear, and one of the stillest that occurred during all of our 

 stay. The barometer began to rise about 8 o'clock, coincidently with the 

 appearance of heavy clouds, followed by rain in the evening. 



The highest thermometers recorded were 64° at 8 a. m., September 18, 

 and 65° at 2 p. m., December 5 ; the wind being northwest on both 

 occasions. The lowest recorded was 23° at 8 p. m., September 26, with 

 a westerly wind. On one occasion, during a night early in September, 

 the thermometer was observed to be as low as 18°, this being the low- 

 est temperature noted. In September the extremes of temperature 

 were 64° and 23° ; in October, 54° and 27° ; in ISTovember, 60^° and 

 33JO ; and in December, 65° and 35°. 



* For detailed meteorological register, see report to Surgeon-General of the Navy, 

 dated June 12, 1875 ; published by Bureau of Medicine and Surgery, 1876. 



