436 Influence of Rocks on Fine Plants. 



Art. XXI. Upofi the Influence of Rochs on the Prosperity of 

 Vine Plants, and upon the Quality of their Produce. By M. 

 Metzger, Curator of the Botanic Garden and Public Arboretum 

 at Heidelberg, Author of Europceische Cerealeen and Der Rhein- 

 ische Weinbau, and other Works (Vol. III. p. 343.) Communi- 

 cated by J. Rennie, Esq. M.A. 



This author, in the work which he has just pubhshed On 

 the Cultivation of the Vine upon the Banks of the Rhine, has 

 examined the influence of the nature of rocks upon the quaU- 

 ties of the soil and vines cultivated in that country, celebrated 

 for the goodness of its wines. The variety of rocks in that 

 country facilitated this comparison, which would be difficult 

 to be established in other parts, and which, at least, will serve 

 as the basis for other researches ; the results at vi^hich he has 

 arrived, are the following : — 



Granite, by the decomposition of mica and felspar, furnishes 

 a very fertile and clayey ground. Qiiartz has a light and 

 porous soil ; it easily admits air, moisture, and heat ; and 

 large bodies retain heat ; there the vine will afford good wine, 

 if all things are equally favourable. 



Sienite produces at least a similar effect. 



Felspar Porphyry, like the granite, furnishes an excellent soil, 

 on which the vine succeeds very well. 



Clay Slate, by its decomposition, supplies a very fertile soil ; 

 if the quartz, which often runs in veins in this rock mix with 

 the soil, it makes it lighter, and renders it more fit for retain- 

 ing heat. The deep colour peculiar to this kind of soil 

 increases also its temperature. This soil is most favourable 

 for the vine. 



Basalt forms, also, b}' its decomposing qualities, a very pro- 

 ductive and suitable soil for the vine, and becomes one of the 

 best, where marl and pebbles of basalt are found mixed to- 

 gether. Its deep colour increases heat, and is one of the 

 principal causes of its fertility for the vine. The best sorts of 

 vines grow on this soil. 



Z)o/mif^ produces the same effect as the basalt; the most 

 valuable wines are supplied from this soil. 



Variegated Sandstone, in consequence of its decomposition, 

 affords a light soil, more or less productive ; where it is not 

 mixed, it is barren, and the vine suffers on it in diy seasons. 

 This is not the case where it is mixed with marl, clay, and 

 other earths ; but in general it produces no remarkable wine. 



The clay soil, which is formed from the decomposition of 

 Shell Marl, is difficult to cultivate. If the calcareous properties 

 prevail, it becomes dry and poor, and requires much manure : 



