Mr. K. B. Hinds on Geoyruphic Botaaij. 15 



calculations arc to be raised. In tixinfj; it at 13 4,000 species, we 

 have attempted to do for Ijotany what Swainson has done for zoo- 

 lo<ry ; but in a conii)aris()n between the two, the number of plants 

 is found to be considerably less than that of animated beings. The 

 great amount of the latter is however chiefly composed of insects, 

 the above author limiting; them at 550,000, whilst he comjnitcs 

 the rest of the animal kingdom at 27,000; the whole clothing 

 the surface of the globe with 71 1,000 different and thstinct forms 

 of organized matter. 



The following will give some idea of the distribution of vege- 

 table forms in round numbers, in the sbc natural di^■isions of the 

 world, and their relative amount to the extent of surface : — 



Square miles. 



Europe . . . 11,200 . . 2,793,000 



Asia .... 30,000 . . 12,118,000 



Afi-ica .... 25,200 . . 8,500,000 



North America . 14,100^ , -, ^^(>^\(^(\ 



South America . 40,000/' ' ^^^^^^^^^^ 



Australasia . . 7,200 . . 3,100,000 



134,000 37,057,000 



As might be expected, by every one the least acquainted with 

 the physical conditions of these sections of the world, there is no 

 connexion between the extent of sm'face and the proportion of 

 vegetation it supports. From the gross result it appears that for 

 eveiy species there is a superficies of 281 square miles of dry 

 land ; a space amply sufficient for the repetition of species in the 

 form of indixiduals, the very numerous multiplications of which 

 clothe the land with vegetation, and is a character which must 

 not be imdervalued, as plants vary much in the number of indi- 

 viduals which are comprehended under different species, and 

 whose abundance constitutes the value of the latter. 



LinnjBus was the first naturalist who ventured an opinion as 

 to the manner in which the earth was originally covered with spe- 

 cies ; he imagined them to have si)read from a common centre. 

 There is no gro\md for supposing otherwise than that all the 

 kingdoms of natm-e had a similar origin and distribution, and 

 that the laws obeyed by one were common to all ; the views of 

 Linnaeus extended to all of them equally. Several theories have 

 been since proposed, but they all may be regarded as one great 

 theory, gradually formed as information accumulated, and step 

 by step enlarging to suit the new facts continually brought to 

 light. The earth being furnished ^nth vegetation at the period 

 mentioned in the sacred writings, no event occurred likely to have 

 a material influence on it, and the botanist, being once acquainted 

 as to the manner of the first distribution, has every reason to re- 



