134 
LIEUT.-COLONRL SABINE ON PERIODICAL LAWS DISCOVERABLE 
If we now refer the 1479 disturbed observations to the respective months of their 
occurrence, we have the numbers severally as follows ; — 
Table VIII. 
January 
208 
i July 
February 
161 
j August 
102 
March 
159 
1 September 
125 
April 
148 
1 October 
May 
48 
' November 
123 
June 
19 
December 
192 
We have here plainly a law of numbers dependent upon the season of the year ; 
but which with some points of resemblance has also some marked points of difference 
from the law found at Toronto. The number of disturbed observations arrange 
themselves at Hobarton in a single progression instead of a double progression as at 
Toronto. The maximum number occurs in December and January, the two mid- 
summer months, and the minimum in May, June and July, the midwinter months. 
The six summer months, October to March inclusive, have 981 disturbed observa- 
tions, and the six winter months, April to September inclusive, 498 ; or on the 
average nearly twice as many in each of the summer months as in the winter months ; 
whilst at Toronto the proportion is more nearly T5 in the summer months to 1 in 
the winter months. If the year be divided into quarters, the summer solstitial 
quarter has the greatest number (523) ; then the two equinoctial quarters (respect- 
ively 468 and 365, the numbers at the autumnal equinox preponderating as at 
Toronto, but the autumn being in this case, February, March and April, instead of 
August, September and October as at Toronto) ; and finally, the winter solstitial 
quarter (123) having here, as at Toronto, a much less number of disturbed observa- 
tions than the other three. 
If we divide the 1479 larger disturbances into easterly and westerly portions 
(Table IX.), we have 613 deflections of the north end of the magnet towards the east, 
and 866 towards the west. The predominance is here of westerly disturbances as it 
was at Toronto of easterly, and as analogy would require, since the stations are in 
different hemispheres and the deflections are of the same end of the magnet at both. 
The proportion in which the westerly deflections preponderate is greater than that of 
the easterly predominance at Toronto, being about T4 : 1 at Hobarton and but T2 : 1 
at Toronto. The westerly disturbances are in excess in every month of the year at 
Hobarton, whereas the excess of easterly disturbances at Toronto prevails only during 
seven months of the year, the westerly being in excess during the winter solstitial 
quarter. But with this difference there is still a considerable analogy preserved ; the 
proportion of easterly disturbances to westerly is greatest in the summer quarter and 
least in the winter quarter at Toronto, whilst at Hobarton the converse proportion 
holds good, the proportion of westerly to easterly disturbances being greatest in tlje 
summer quarter and least in the winter quarter at Hobarton. 
