VI INTRODUCTION. 



to include Tasmania (Van Diemen's Land), and all 

 the islands in the vicinity of the Australian con- 

 tinent. 



All bearings and courses, unless it is specified to 

 the contrary, are magnetic, according to the varia- 

 tion during the period of the Beagle's voyage. 



The longitudes are generally given from meri- 

 dians in Australia, as I much question whether 

 any portion of the continent is accurately deter- 

 mined with reference to Greenwich. Sydney, Port 

 Essington, and Swan River, have been the meri- 

 dians selected ; and the respective positions of those 

 places, within a minute of the truth, I consider to 

 be as follows : — 



Swan River (Scott's Jetty, Fremantle) 1 1 5" 47' E^ 



Port Essington (Government house) . 132" 13' E. 



Sydney (Fort Macquarie) .... 151° 16' E. 



