82 Prof. B. Stewart on Magnetic [Feb. 7, 



nation-range, corresponding to 48 points in the year, the whole series 

 of eleven years being taken. 



Table I. — Containing monthly means (48 to the year) of the diurnal 

 declination-range, thns : — January (0) denotes the monthly mean 

 of which the middle date is the very commencement of the year ; 

 January (1) that of which the middle date is one quarter-month after 

 the commencement, and so on : — 



Date. 



January (0) 

 (1) 



(2) 

 (3) 



February (0) 

 „ (1) 



(2) 



„ (3) 

 March (0) 

 (1) 

 (2) 

 (3) 



April (0) 

 (1) 

 (2) 

 (3) 



May (0) 

 (1) 



(2) 

 (3) 



June (0) 

 (1) 



(2) 

 (3) 



Series 

 1854-64. 



2-97 

 2-98 

 306 

 300 

 2-86 

 2-70 

 2-50 

 241 

 229 

 215 

 204 

 196 

 2-06 

 2-24 

 2-42 

 265 



2- 87 



3- 04 

 325 

 325 

 329 

 330 

 332 

 342 



Date. 



July (0) 



(1) 

 (2) 

 (3) 



August (0) 

 (1) 



(2) 

 (3) 



September (0) 

 (1) 

 (2) 

 (3) 



October (0) 

 (1) 

 (2) 

 (3) 



November (0) 

 „ (1) 

 (2) 



„ (3) 

 December (0) 

 (1) 

 (2) 

 (3) 



Series 

 1854-64. 



3 46 

 344 

 337 

 341 

 3-60 



3- 80 



4- 00 

 4-17 

 415 

 4-03 

 366 

 315 

 273 

 2-40 

 2-27 

 226 

 235 

 255 

 2-72 



2- 90 



3- 07 

 3-08 

 312 

 3 02 



3. It will be noticed from this table that the annual variation of 

 the declination-range at Trevandrum is very different in character 

 from its annual variation at the Kew Observatory. 



The chief feature of the annual variation at Kew is the small value 

 of the range at the time of the winter solstice. 



On the other hand, the chief features of the annual variation of 

 declination-range at Trevandrum are two minima, nearly correspond- 

 ing in time to the two equinoxes, and two maxima, one large, some 

 time in August (after the summer solstice) and a smaller one about 

 the time of the winter solstice. These features have been already 

 remarked by Mr. Broun, who has likewise pointed out that the 

 character of the diurnal variation of the declination at the summer 

 solstice is at Trevandrum the opposite of its character at the winter 

 solstice — the change from the one type to the other taking place about 

 the equinoxes. He has likewise pointed out, as a result of this 



