82 The Rev. H. Lloyd on the Besults of Ohsenations made at the 



The numbers of the preceding Table, notwithstandhig some irregularities, 

 exhibit very distinctly the influence of season upon the critical hours. The 

 epoch of greatest ivesterhj elongation occurs latest about the time of the summer 

 solstice ; and earliest in the last quarter of the year, or between the autumnal 

 equinox and the winter solstice. The same thing holds with respect to the 

 epochs of mea7i declination, which (as might have been expected) appear to be 

 governed in great measure by the time of westerly elongation. 



The epochs oi greatest easterly elongation appear to be governed by the times 

 of sunrise and sunset, and are, consequently, much more variable. The fore- 

 noon easterly elongation is earliest about the time of the summer solstice, and 

 latest at that of the winter solstice ; while the case of the afternoon easterly 

 elongation i s nearly the reverse. In the months of May, June, and July, in 

 fact, there is no change in the direction of the movement during the night, but 

 the needle is qiiiescent for a few hours after midnight, and then the north pole 

 resumes its easterly movement until after 6 a. m. 



The critical hours of greatest constancy throughout the year are those of 

 the greatest westerly elongation, and those of the forenoon mean ; the extreme 

 difference between any of these hours, and the mean for the entire year, being 

 twenty-eight minutes. The differences are much lessened, if apparent be sub- 

 stituted for mean time. 



11. I proceed, in the next place, to state the results connected with the 

 diurnal range. 



The morning easterly elongation being greater than the evening one in sum- 

 mer, and less in winter, it follows that a complete view of the phenomena 

 connected with the magnitude of the oscillation cannot be had, without 

 taking into account the double range. This is accordingly done in the fol- 

 lowing Table, the first column of which gives the range of the westerly 

 movement, between 7 A. m. and 1 p. m., nearly ; and the second that of the 

 succeeding eastei'ly movement, from 1 p. m, to 10 p. m. nearly. 



