Meteorology. 329 



The geographical co-ordinates of the place are 45° 32^ north 

 latitude, and *J^° 36^ longitude west of Greenwich. The cis- 

 terns of the barometers are placed at 118 feet above the level of 

 the sea. The instrumsnts used are standard instruments; the 

 barometric observations are all reduced to the freezing point, 

 (32° F.) and the temperatures are all in Farenheit's scale. The 

 hygrometric observations are reduced by the tables and formula 

 adopted at the Greenwich observatory in England. The receiver 

 of the rain guage is placed 20 feet above the soil. The direction 

 and velocity of the wind is ascertained by a self-registering 

 instrument which indicates its velocity by dots on a paper regis- 

 ter in miles linear. The electrical apparatus is provided with a 

 collecting lanthorn which is elevated 80 feet from the ground. 

 The solar and terrestrial radiators are also read in terms of Faren- 

 heit's scale. The ozonometer is of Schonbien's construction. 

 The whole of the means are reduced from three daily observa- 

 tions, taken at 6 a.m., 2 p.m., and 10 p.m. ; extra hours are also 

 set apart for any unusual phenomena. 



Barometer. — The mean h eighth of the barometer for this 

 period (7 years) was 29.676 inches, the mean reading for the 

 same septennial period in January was 29.744 inches, February 

 29,744 inches, March 29,492 inches, April 29,679 inches. May 

 29,604 inches, June 29,718 inches, July 29,716, inches, August 

 29,754 inches, September 29,722 inches, October 29,619 inches, 

 November 29,769 inches, December 29.565 inches. The highest 

 reading observed and on record here -vias on the 8ih January 

 1855, and at 4 p.m. it attained the unusual height of 30.876 inch. ; 

 the lowest reading on record was in December also in 1855, and 

 was 28,689 inches, giving an absolute range of 2,187 inches. 

 The mean yearly range for the 7 years was 1,032 inches, and for 

 the months as follows : 



inches. 



January, 1,550 



February, 1,131 



March, 1,145 



April, 1,090 



inches. 



May, 0,800 



June, 0,'752 



July, 0,616 



August, OjtOl 



inches. 



September, 0,815 



October, 0,951 



November, 1,295 



December, 1,538 



There are two maxima and two minima variations occurring 

 in the barometer in the 24 hours ; the maxima variation occurs at 

 between 9 and 10 o'clock a.m., and between 9 and 10 p.m., the 

 minima variations occur at 3 a.m., and 3 p.m. 



Thermometer. — The temperature of the air for the same period 

 (7 years) exhibits a yearly mean of 41° 56\ The mean tem- 



