OF THE EARTH’S MAGNETISM. 545 
88. These ranges show nearly the same ratios as the sums of daily changes 
(Table XXII.); but when we take the movements after August 1844, where they 
again become well marked, we find— 
TABLE XXVI.—Rancss oF (26-27) Day Periop: AuGcust To NOVEMBER 1844. 














PERIOD. Makerstoun. | Trevandrum. | Singapore. Hobarton. 
Aug. 2 to Sept. 2, 6:26 9°37 7:08 G3 
MED oe Octen)y Ls 10°81 13-80 10-01 11:30 
Sept. 30 ,, Oct. 21, 12°55 14°88 12-44 13°55 
Oct. 20 ,, Nov. 22, 14:97 11-48 10-91 12°47 
Sun, 44°59 49°53 40°44 45:05 
Ratio to Hobarton, 2 0:99 1-10 0:90 1:00 



In these instances the ranges are nearly equal at all the places. 
89. And if we combine the sums of both groups, we have— 
TABLE XXVII.—SuMs oF RANGES OF BOTH GROUPS. 













ARGUMENT. Makerstoun. | Trevandrum. Singapore. Hobarton. 
Sum of both groups, 78°72 76°43 63°15 68:03 | 
Ratio to Hobarton, AAG LoL 0:93 1:06 


90. The ranges of these movements are only affected by disturbances in as 
far as the maxima or minima are concerned; and we might expect that, if the 
movements should be equal at all places independently of local disturbance, the 
ratio would be much nearer a ratio of equality than in the case of the sums of 
daily changes. This is the case in the means of the ranges for these eight 
periods; and it follows as very probable that the range of the 26-27 day period 
is nearly equal at all the stations. 
91. In order to examine more carefully the relation of these movements, I 
chose one of the most marked, that included within five weeks February 4 to 
March 8, 1844; though the agreement of the smaller movements within this 
period is by no means so well marked as in many others, and I included two 
other stations, the Cape and Toronto. Commencing with January 28, I obtained 
