240 Observations upon the effects of Frost, 



The utmost which science can at present do, with reference to 

 this subject, is to judge from probability. We know that the more 

 nearly the climates of different countries approach each other, the 

 greater the probability that the species peculiar to those countries 

 may be advantageously interchanged. But although this is a 

 valuable guiding fact for general purposes, it loses its value, or at 

 least from the imperfection of our information appears to lose it, 

 when we descend to particulars. Because the climate of many 

 parts of the Himalaya mountains resembles that of England, it is 

 probable that the plants of the former will grow in the latter 

 country, and experience shows that this will really happen. But 

 while such is the general fact we continually find exceptions to it, 

 which nothing but actual experiment could have led us to discover. 

 For instance the Deodar cedar appears hardy all over England, 

 but Abies Webbiana suffers so much from cold, that it is doubtful 

 whether it is likely to be of national importance in the midland 

 and northern counties, except in very favourable situations; yet 

 they are both from the same tracts of country, and we could not 

 have judged beforehand that their constitution would be different. 

 In like manner, Benthamia grows on the second range of the Hima- 

 laya mountains, along with Berberis aristata, asiatica, and others, 

 and belongs to as hardy a family as they do. Yet Benthamia has 

 been almost everywhere killed by the frost, except in Devonshire, 

 Cornwall, and South Wales, and the others have as generally 

 resisted it ; and there is no apparent or theoretical difference in the 

 nature of these plants to account for the difference. Again, if we 

 could judge beforehand of such things, it would be said that the 

 climate of Van Diemen s Land, especially that of the southern face 

 of the island, would yield plants suitable to Devonshire ; and such 

 appears to be the fact with such species as Acacia stricta and diffusa, 

 Correa alba, Callistemon lanceolatus, Grevillea rosmarinifolia, and 

 some others ; but on the other hand, Aster argophyllus, Poma- 

 derris elliptica and Veronica decussata, which is quite a mountain 



