3-18 
CAPTAIN E. W. CREAK ON THE M AGATE TIC AL 
Differences between “ Penguin ” and Observatories. 
s. 
H. 
o. 
Needle. 
j At Kew. 
+ 2 : 0 
25 a., +’00019 
—0’9 
1 
25 d., +’00014 
-3’4 
2 
. 
+ 1-4 
o 
O 
+ 0*4 
4 
At Melbourne 
+ 7-2 
25 a., --00004 
+ 2-7 
1 
25 d., — ’00026 
+ 1-4 
2 
+ 2-3 
o 
O 
+ 4+ 
4 
At Hong Kong . 
+ 1-8 
25 a., + ’00045 
-0-5 
1 
25 d., +’00036 
-1-0 
2 
-0’4 
*> 
o 
+ 0-8 
4 
Observing how nearly the “Penguin’s” results agree with those of Kew and 
Hong Kong, it seems fair to assume that, in spite of the increased discordance 
observed at Melbourne, the instruments remained in a satisfactory condition 
throughout the period of observation. 
It is not proposed to record here in full the moments of the two magnets observed 
in the Force observations, but it may be explained that the several values were 
treated graphically, with the following results :— 
Magnet 25, a. 
Magnet 25, d. 
March, 1890 . 
m = ’029172 
•027568 
December, 1890 .... 
= -029094 
•027494 
February, 1892 .... 
= -029050 
•027469 
September, 1893 .... 
= ’028995 
•027328 
Thus, during the first nine months, the moments of both magnets declined 
somewhat rapidly, after which they slowly diminished in value until the close of the 
series at Kew. It may be noted that, throughout the series, no single value of m 
differed more than dr '00001 from those of the curve obtained from the whole set 
employed for obtaining H. 
The value of P has been calculated by the formula 
(Log A ; — logAo) X 5'64 = P 
where A, and A 3 are the values of m /PI at the two distances. The mean value for 
the whole series is 
P = — '00080228. 
