1895.] the Voyage of ILM.S. " Penguin," 1890-93. 221 



The magnitude of the subject is self evident, therefore it is pre- 

 sumed that under existing circumstances of paucity of information,, 

 any well conducted series of observations of the kind required will 

 be welcomed. 



H.M. surveying ship " Penguin " being ordered to survey the 

 West Coast of Australia, proceeding there by way of the Suez Canal, 

 it was decided to equip that vessel with the necessary absolute 

 magnetic instruments for observations on land and other necessary 

 instruments for relative observations on board the ship. The 

 " Penguin " being practically an iron ship, general observations of 

 the magnetic elements at sea were not undertaken, but the special 

 attention of the observing officers was directed to obtaining the 

 following observations : 



(1.) The magnetic elements on land at all ports visited. 



(2.) Local magnetic disturbances on islands. 



(3.) The magnetic survey of the West Coast of Australia, which, 

 until the " Meda's " observations in 1885-86, was a terra incognita as 

 far as the inclination and force were concerned. 



(4.) The position and extent of an area of remarkable local 

 magnetic disturbance, reported by H.M. surveying vessel " Meda " 

 as situated under the sea at Port Walcott (N.W. Australia) and two 

 miles from the visible land. 



With regard to (1) A series of observations with the absolute 

 instruments were made at twenty-three different places situated on 

 the route from Malta, via Australia, to Hong Kong. These are 

 shown in Table I. 



For (2) Observations of local magnetic disturbance on land were 

 made at Perim Island and Baudin Island (N. Australia). At 

 Perim the principal disturbance was found in the inclination, being 

 about 1 to 2 in value. At Baudin Island, the declination was 

 disturbed 5^, the inclination 2f. Horizontal force undisturbed. 



For (3) The magnetic elements were observed at twelve stations 

 between King George's Sound and Baudin Island. 



With regard to (4), the chief interest lies in the area of disturbance 

 termed a " magnetic shoal," from its situation at 9 fathoms below 

 the sea level. Four days were devoted to the survey of this shoal, 

 whilst observations were being made on the neighbouring land. 

 (Data contained in Tables III and IV.) This survey was neces- 

 sarily carried out on board the ship with the relative instruments. 



The results were the mapping of an area of maguetical disturbance 

 3 miles long by If miles average width, extending in a north-easterly 

 direction. The positions of the greatest easterly disturbance and 

 westerly disturbance having been found in proximity to one another, 

 the ship was moored in the neighbourhood, and observations of decli- 

 nation, inclination, and total force made. From these a sectional 



