of the Climate of Naples upon the Periods of Vegetation. 275 



attention of botanists to this study; for in his writings are 

 to be found many observations on the distribution of ^plants 

 over the different regions of the world. 



But the principal authors who have, within these few years, 

 brought botanical geography again into notice, and have given 

 to the world a vast deal of scientific information, collected in 

 various parts of the globe, are Humboldt, Bonpland, De 

 Candolle,Ramond,DeBuch, Schouw, Mirbel, Tenore, Robert 

 Brown, Winch, and Wahlenherg. Dr. Schouw published in 

 1822 a work in Danish, entitled " A Prodromus of the Uni- 

 versal Geography of Plants." It was translated into German, 

 and published at Berlin in 1823. 



How unfortunate it is that so much valuable learning on 

 this subject remains locked up in an " unknown tongue," at 

 least with respect to most of the botanists of England ! I 

 must therefore only hope that some German scholar will 

 ere long be persuaded to translate it, either into French or 

 English, since it is accounted by the botanists of Germany a 

 work of general utility on this head. 



But there is a part of botanical geography still less known 

 than that which relates to the laws of the distribution of 

 plants over both hemispheres ; I allude to the influence which 

 climate exerts upon vegetation in different places in the world. 

 And, indeed, one of the most accomplished and learned men 

 of our age* has said, that " the connexion of the law of the 

 distribution of the generic forms of plants over the globe with 

 the laws of climate constitutes one of the most interesting and 

 important branches of natural-historical inquiry, and one on 

 which great light remains to be thrown by future researches." 

 Now it is with the view of introducing this particular subject 

 to the readers of your Magazine that I have been induced 

 to send to you the following sketch : and I earnestly wish 

 that some of them may continue with zeal and care any in- 

 quiries that they may already have begun on the periods of ve- 

 getation ; and at the same time they ought minutely to notice 

 the different degrees of temperature and moisture according 

 to the respective seasons of each year. For by a comparison 

 of many nice observations, carried on in different parts of the 

 world, at different elevations and in different seasons, we may 

 ultimately be enabled to arrive at a more certain knowledge 

 of the laws of climate. 



The greater portion of this paper I have translated from 

 the 8th chapter of an " Essay on the Physical and Bo- 



♦ Sir John F. W. Henciiel. Se« his " Discourse «" th« Study of Na- 

 tural Philosophy," p, 345. 



2 N 2 



