Sun-spots and Terrestrial Phenomena. 253 



Trevandrum are curved on the same form — the former in a weaker and 

 the latter in an interrupted line. 



4. On these curves we may remark that they present snch a general 

 correspondence of movement, and approach to simultaneity, that any 

 conclusions as to the relations of the declination-range to solar 

 activity that may be drawn in respect of one of them will apply 

 generally in respect of the others also. The sun-spot period is 

 distinctly followed by them all — three showing the maximum of 

 1859-60, and two the minima about 1856 and 1866-67. The 

 general correspondence of the curves will perhaps be most readily 

 apprehended by noting the most marked cases of departure from it : 

 these are — (1) that the elevation, in the middle of 1859, in the Kew 

 and Bombay curves, has no counterpart in that of Trevandrum, but 

 only a slight inflection of a continued rise ; (2) that the depression, at 

 the beginning of 1861, at Trevandrum and Bombay, is all but absent 

 at Kew ; and (3) that the elevation, near the end of 1862, at Kew and 

 Trevandrum, has no counterpart at Bombay. 



Features of the Trevandrum and Bombay curves that are perhaps 

 worth noting are that the great rise from 1856 to 1860 begins earlier 

 and ends later at Trevandrum than at Bombay, that it begins lower 

 and ends higher, and that the turnings at beginning and end are 

 sharper in the same case. 



C. Lunar Annual Variation. 



D. Semi-annual Lunar Variation. 



5. The processes by which the lunar variations of declination-range 

 nave been brought out were the same as were applied to the tempera- 

 ture-ranges in paragraphs 7 to 13 of the preceding investigation ; but 

 the observations made use of in the case of the declination-ranges 

 are those for the twenty-five winters and twenty-five summers em- 

 braced between 1847*75 and 18 71' 75. In this case a lunation was 

 taken to be a winter one if the middle of it occurred between the 1st 

 October and 1st April, and the remaining lunations were taken as 

 summer ones ; and- — in correspondence with this — the elimination of 

 the part of the winter or summer lunar variation due to the annual 

 variation of the declination-range was effected by the same division of 

 the year in respect of summer and winter. The following table shows 

 the mean values of the declination-range for each of the eight phases 

 of each of the 309 lunations of the period, and the summer lunations 

 are distinguished in it by having their serial numbers enclosed by 

 parentheses. 



