THE TRISTAN DA CUNHA GROUP. 



INTRODUCTORY NOTES. 



Position and Physical Conditions, &C. 1 



The Group consists of three principal islands, named Tristan da Cunha, Inaccessible, and 

 Nightingale, and a few outlying islets. Tristan da Cunha itself is in lat. 37° 2' 48" S., 

 and long. 12° IS' 20" W. of Greenwich, and the other islands are distant from it 

 respectively about twenty-three and twenty miles to the south-west, Inaccessible Island 

 being nearly equidistant from the other two, and the most westerly of the group, which 

 lies about one-third nearer to South Africa than it does to any part of South America. 

 Like the majority of the islands dealt with in this work, they are of volcanic origin. 



Tristan da Cunha is circular in form, has an area of some sixteen square miles, and 

 rises in the centre to an altitude* of upwards of 8000 feet above the sea-level. It rises 

 like one mass of rock abruptly from the sea, ascending, according to Carmichael, at an angle 

 of forty-five degrees to the height of 3000 feet ; and this mass is surmounted by a dome 2 

 upwards of 5000 feet high, on the summit of which is the crater of an old extinguished 

 volcano. There is a water-colour drawing of it by Carmichael in the Timber Museum 

 at Kew. 



Inaccessible Island is the next in size, being four and a half miles long by about two 

 miles broad, and its greatest altitude is 1840 feet. 



Nightingale Island is less than a square mile in area, and its highest peak is 1100 feet. 



With regard to the climate of this group, there are no records of any series of 

 observations ; but we learn from the accounts of different travellers that on the whole it 

 is very rough and wet, though pleasant enough at certain seasons. Captain Carmichael, 3 

 who spent four months (November to March) on Tristan da Cunha, gives the following 

 particulars : — 



" The climate of Tristan da Cunha is so mild, that the herbage remains unimpaired throughout 

 the year. Snow is never seen on the low land ; and the only indication of winter is a transient 



1 Restricted here to the broadest features : further particulars will be found in some of the extracts from 

 Carmichael's and Moseley's descriptions of the vegetation, &c. 



2 This word is borrowed from Carmichael because he so frequently uses it in localising his plants. 



3 Transactions of the Linnean Society of London, xii. (1818), p. 491. 



