The magnetic survey of Tasmania. 



By Professor E. G. Hogg, M.A. 



\_Read before the Royal Society of Tasmania, 

 13 August, 1900.] 



Section 1. The History of Magnetic Observation in Tasmania. 

 Section II. Magnetic work in Victoria and New Zealand. 

 Section III. The work of the proposed Survey. 



I. The History of Magnetic Ohseroation in Tasmania, 



The earliest record of a magnetic determination in 

 Tasmania I owe to the kindness of Mr. T. Stephens, 

 M.A., one of the Vice-Presidents of this Society. From 

 his communication to me it appears that when Sir John 

 Franklin founded the village of Lachlan in 1839 the 

 magnetic declination at Lachlan was 10° 10^ E. 



In the first volume of the Tasmanian Journalis a copy 

 of the communication addressed bv Sir James Ross on 

 the 7th April, 1841, to the British Admiralty, in which 

 he sets forth, among other matters, his discovery of the 

 position of the southern magnetic pole. In latitude 76° 14^ 

 S. and longitude 164° E. he found tlie magnetic dip to 

 be 88-40°, and the declination 109*24° E. ; from which 

 he deduces that he was then only 160 miles from the 

 magnetic pole. • The impetus given to magnetic research 

 by his discovery was, probably, the determining cause 

 which led to the subsequent selection of Hobart as the 

 spot on which were afterwards carried out the first 

 systematic magnetic records ever made in Australasia. 



From its southerly latitude, its situation relative to the 

 great land-mass of Australia, and its position almost in 

 antipodes to Great Britain, Tasmania is eminently fitted 

 as a station for magnetic observations, and, recognising 

 this, the Royal Society of London, in the early forties, 

 fitted out a complete survey party, with the latest form 

 of instruments, to investigate, under the superintendence 

 of Lieut. Kay, R.N., the magnetic elements of Tasmania, 

 and to determine the rate of variation of these elements. 

 The instruments were set up in the Domain, not far from 

 Government House, and observations Avere taken cover- 

 ing the period from 1842 to 1850. The results obtained 

 in Hobart were subjected to the closest examination by 

 Sir Edward Sabine, and from them, taken in conjunction 



