Observations upon the effects of Frost, 



Verbena Melindres, lived in open ground at Arundel Castle, pro- 

 tected with a covering 6 inches deep of leaves. 



Volk ameria inermis was killed to the ground in the Society's 

 Garden, but sprang up again with rather strong shoots. 



Zephyranthes Candida sustained no injury at Spofforth, even in 

 the leaves ; but it was killed at Dropmore. 



The results of these returns, and of the numerous observations 

 made in the Garden of the Society, are less conflicting than they 

 usually are in such inquiries. The effects of cold are so much 

 modified by soil, by the surrounding atmosphere, by a variety of 

 local causes which are often not appreciable, that perfect uniformity 

 in apparent results cannot be expected. This has long since been 

 observed by Humboldt and other writers upon Botanical Geogra- 

 phy, in comparing one country with another ; it has been found 

 that parallels of latitude offer by no means an indication of uniform 

 temperature, as they would do, if the globe were a sphere with a 

 perfectly level surface, and a homogeneous crust, but that the mean 

 temperature of some countries, Lapland for instance, is much higher 

 than it should be, from their position with regard to the equator. 

 Such being the case with respect to large tracts of land, it a fortiori 

 would be expected in different localities on such an island as 

 Great Britain, with its diversity of coast, wood, mountains, and ex- 

 posure to the ocean ; accordingly we find in the garden of Mr. Fox, 

 at Grove Hill near Falmouth, not only that such common green- 

 house plants, as Acacia armata, and longifolia, Brugmansia suaveolens, 

 Calothamnus quadrifida, and several Cape Heaths, survived last win- 

 ter, although they perished in other places in Cornwall, but that the 

 much more tender species Dracaena fragrans, Justicia Adhatoda, 

 Thunbergia coccinea, which are generally regarded as stove plants, 

 were also uninjured. In this garden Acacia armata has been 

 growing 16 years, Aloysia citriodora 24, the red Camellia japonica 

 25, Jasminum revolutum 15, Leptospermum ambiguum 17, Cal- 



