76 Sir 'Thomas Brisbane's Meteorological Tables. 



Hence the mean annual temperature of Hobart Town at 

 a point 28^ f eet above the level of the sea, and situated in 

 42° 53' 22" of south latitude, and 147° 34' 39" of east longi- 

 tude, is 52*. 42; and the mean annual temperature of Mac- 

 quarie Harbour, at a point 26 feet above the level of the sea, 

 and situated in 42° 11' 38" of south latitude, and 145° 27' 

 30" of east longitude, is 55°. 44. 



"S 



As these observations, along with those made at Paramatta, 

 are the only ones that have been made in the southern hemi- 

 sphere, with the exception of those made at the Cape of Good 

 Hope, they become of great importance, in so far as they 

 enable us to compare the distribution of heat in the southern, 

 with that which takes place in the northern half of the globe. 



The latitude of Hobart Town does not differ greatly from 

 that of Rome, and yet the mean temperature of Rome is 

 60°. 44, while that of Hobart Town is only 52°. 42, making a 

 difference in favour of the European climate of nearly 7°, 

 when an allowance is made for the difference of latitude. 



On the other hand, the town of Salem in Massachusets, 

 which has almost exactly the same latitude as Hobart Town, 

 possesses a mean temperature of 48°.68, making a difference 

 in favour of the Australasian climate of nearly 4°. 



The climate of Hobart Town, therefore, is intermediate 

 between that of Europe and America, and affords us reason 

 to believe that the isothermal lines in the southern hemi- 

 sphere are related, as they are in the northern one, to two 

 poles of maximum cold, which have nearly the same position 

 as the magnetic poles of the earth. 



In order to determine this point, I have computed the 

 mean temperature of Hobart Town, by supposing the poles 

 of maximum cold to have the same position in the southern 

 as they have in the northern hemisphere. If we suppose the 

 pole nearest to Hobart Town to have the same degree of 

 cold as the American pole, then the mean temperature of 

 Hobart Town will be 53°.ll ; differing little more than half a 

 degree from the observed mean temperature ; and if we sup- 

 pose it to be the same as the Asiatic Pole, the mean tempera- 

 ture will be 54-°.67, differing 2° from observation. It de- 

 serves to be remarked, however, that both these computed re- 

 sults lie between the mean temperature actually observed at 



