230 
ON ROCKERIES AND ALPINE PLANTS. 
rockery may partake more of a natural character, and be of more extended dimen- 
sions. And where expense is not an object, collections may be made of all the 
most beautiful descriptions of rock from all parts of Britain, or even of Europe, 
blending with them large and curious shells, and observing to place the latter in 
conspicuous situations. 
Connected with the rockery, a grotto or cave may be easily constructed, which 
will be quite in character with the whole erection. This species of garden orna- 
ment has latterly fallen into disuse, but it certainly deserves to be revived. It 
should be so contrived as to be quite dark, and the roof and sides should be formed 
of some lucid and transparent kind of rock or spar, so that, when illuminated, it 
will have a most brilliant appearance. 
We proceed, however, to speak of the purposes of utility which a rockery will 
supply, confining ourselves chiefly, and indeed solely, to the capabilities it affords 
of growing Alpine plants. By the term Alpine plants, we may be understood to 
imply not only such as are really found on the Alpine chain, but all those which 
grow naturally on any description of rock or stone ; in short, it is perfectly synony- 
mous with rock or mountain plants. These most interesting little objects, — for they 
are all of them of dwarf habits, — like the materials most congenial to their growth, 
are by no means regarded as they deserve to be by plant cultivators ; the reason of 
which probably is, that few persons seem disposed to make a sufficient inquiry 
into their habits, to enable them to grow them to perfection, or even to preserve 
some species alive. 
It appears to be a general, though without question a most mistaken, notion, 
that because Alpine plants are found growing on the summits of mountains, in 
very elevated and exposed situations, they are capable of enduring an intense 
degree of cold. Acting upon this supposition, cultivators never think of affording 
them any shelter during the winter months, and the consequence is, that very 
many of them perish in severe weather. Now, upon a careful examination 
into the circumstances in which they are naturally placed, it will be found that so 
far from their ever being exposed to the action of intense cold, they are always 
enveloped, as it were, in a thick mantle of snow, through the winter months, 
which is absolutely impervious to severe frost. 
In the present age of scientific discovery, and the almost universal diffusion of 
scientific information, it seems almost needless to state that snow forms a protecting 
screen to vegetable substances, equally, if not more secure, than any materials 
which the art of man can apply to the surface of the ground. We believe we are 
correct in saying, that the temperature of snow, at least where there is any 
bulk or depth of it, is constantly maintained at a very trifling degree below freez- 
ing point, and that only the mere surface of it is at all affected either by cold or 
heat. From this it will be evident, that in the mountainous regions which are 
inhabited by Alpine plants, and which are almost perpetually covered with snow, 
no degree of cold, beyond that of the substance just mentioned, can ever reach 
them. 
