( io ) 



hours for every year and for tb e three years together were 

 then taken. 



The results are contained in Table I. The means for 1866 

 are deduced froni the observations made from January l6 tl! , 

 1866, to January 5 th , 1867; those for 1867 from the ob- 

 servations made from January 5 th , 1867, to December 26 th 

 1867; those for 1868 from the observations made from 

 December 26 th , 1867, to January 12 th , 1869. 



