RESULTS OF THE VOYAGE OF H.M.S. PENGUIN. 
359 
nearer the source of disturbance than the observing instruments, placed in different 
parts of so powerful a magnetic field, was subject to a measure of induction which 
there was no means of gauging. 
It was suggested that observations to test the effects of this induction might be 
made on a wooden raft, but neither the state of the sea nor time available permitted 
this. 
On the possible Cause of the Disturbances. 
Having in possession the amount of the several disturbances observed, the question 
arises what is the disturbing cause ? It is certain, by the sea soundings, that the 
source of the disturbance was some 82 feet below the Force instruments. 
Referring to Diagram A, the central line of no disturbance is clearly defined by 
the change of sign in the observed values of the disturbances, and this line may be 
termed a “ ridge line” extending with its sinuosities for a distance of 3'5 miles, and 
passing through the point of greatest upward Vertical Force disturbance. Points of 
decreasing value of upward Vertical Force are shown at P~ and D 1 , whilst at D 3 the 
disturbance is comparatively small and downwards. 
Also in Diagram D a transverse sectional line will be seen passing across the 
curves. This line passes through the area of greatest disturbance in the Vertical 
Force and of the Declination, and its direction has been selected as also passing 
through points in the curves which are best authenticated by observation. 
The principal results, therefore, may be expressed shortly as follows :—At a point 
situated N. 78° E. (true), distant 2T55 miles from the Station on Bezout Island, 
there exists in the land below the sea a source of magnetic disturbance, causing 
disturbances of the following magnitude :— 
Declination. 
Dip. 
Hoi'izontal Force. 
Vertical Force. 
26 3 W. to 56° E. 
on N. side on S. side. 
-29° 
+ 1-04 to -1-92 
on N. side on S. side. 
— 4 - 44 to + 0'32 
Of the nature of the land under the sea causing such abnormal magnetic disturb¬ 
ances, there is scant information upon which to form any decided opinion. A. 
geological survey of the most disturbed part of the coast at Bed Cliff was made by 
Mr. Walker, Chief Engineer of the “ Penguin,” which is given in full with diagram 
in Appendix B. 
A number of specimens of rock and sand were collected by the “ Penguin ” in 
several parts of Australia, which Professor Pucker has been kind enough to examine. 
Among these was a specimen of sand taken from the bottom where the magnetic 
