gate bearings of the streets parallel to North and South 

 terraces are found to be 30' higher than the mean aggregate 

 bearings of the streets parallel to AVest-terrace and King 

 "William-street, even after all allowance has been made for 

 defect of alignment, and due precautions taken to secure their 

 intersections at right angles to one another. The average of 

 80 readings brings out a magnetic bearing of iS^. 81° 10' E. for 

 streets parallel to JSouth-terrace, and of 'N. 9° 20' AY. for Xing 

 William- street and the streets parallel to it. The true bear- 

 ings, determined astronomically, are 86° 28', and 3° 32' res- 

 pectively ; so that one set of observations gives a magnetic 

 variation of 5° 18', and the other a variation of 5° 48'. The 

 discrepancy is attributed by the author to local attraction — as, 

 for instance, by telegraphic wires, gas and water mains, 

 building stone* &c. The author is disposed to believe that the 

 latter more nearly represents the true magnetic bearing. 



It is difficult, however, to assign a definite value to the mag- 

 netic declination at any epoch until the laws of the diurnal 

 and other oscillations are more completely known. The author 

 has made many observations on the diurnal oscillation. At 

 Adelaide the needle moves towards the east from about 8 a.m. 

 until after 1 p.m., and returns during the afternoon to the 

 position it occupied in the morning. This is, of course, the in- 

 verse of what is observed in the northern hemisphere. The 

 range at Adelaide was observed by the author to be 13' in 

 December, 1883 ; 4' in May, 1884 ; andf as much as 16' in 

 October, 1884. 



* The author has found the stone walls of his house to be strongly 

 magnetic. 



t Added since the paper was sent in. 



