MADE AT BEUNSWICK, MAINE. 



49 



1808. 



June 



26th 



2'' 51" A. M. 



1814 



Novembei 



28th 



1" 15" P. M. 



ISIT 



May 



22d 



S"" 10" (not stated whether A 



1823 



March 



7th 



1 (about) ( " " 



1828 



July 



25th 



6"^ 30" A. M. 



1828. 



August 



14th 



10" (about) (not stated whether A 



1829. 



August 



26th 



g'' 15" P. M. 



MISCELLANEOUS PHENOMENA. 



Earthquakes. 



Seven earthquakes were found recorded during 51 years, between 1807 and 

 1859. There is no record of the year 1853. The dates are as follows: — 



M. or P. M.) 



Aurora Borealis. 



During the same period (51 years) as above, there were observed 86 auroras. 

 That this is the total number which occurred may well be doubted, and they include 

 probably only the brighter exhibitions. In their monthly occurrence they group 

 themselves about the equinoxial months, especially about the autumnal equinox. 







6 



18 



n 



That there exists also a periodic or secular variation appears with sufficient dis- 

 tinctness from the following figures : — 





DiSTKIEUTION OF AdK 



OKAS DURING THE YeAE. 



January . 



. 4 



July 



February . 



. 10 



. August . 



March 



. 10 



September 



April 



. 6 



October . 



May 



. 1 



November 



June 



. 1 



December 





Table XVII. — Numbee of Auroras observed each 



Tear. 





1807 



2 



1820 



1 



1833 



3 



1846 





1808 



12 



1821 



— 



1834 



— 



1847 







1809 



— 



1822 



— 



1835 



1 



1848 



6 



1810 







1823 







1836 



2 



1849 



1 



1811 







1824 



— 



1837 



2 



1850 







1812 







1825 



— 



1838 



8 



1851 







1813 







1826 



— 



1839 



6 



1852 







1814 



3 



1827 



6 



1840 



3 



1853 







1815 



2 



1828 



1 



1841 







1854 







1816 







1829 



6 



1842 







1855 







1817 



1 



1830 



8 



1843 







1856 







1818 



6 



1831 



2 



1844 







1857 



1 



1819 



3 



1832 





1845 





1858 

 1859 



- 



We have therefore the following years of maxima of auroral displays: 1808, 

 1818, 1830, 1838, 1848, 1857, leaving differences of 10, 12, 8, 10, and 9 years. 

 This indicates a period of about 10 ± 2 years. 



The greater frequency of auroral lights about the time of the equinoxes, and the 



May, 1867. 



