The depth of the soil is a matter that varies in accordance with the climate.  In warm districts the vine requires more room for development, and goes deeper.  In the cooler regions it has a sufficiency of moisture, and can content itself with a shallower soil.  The colour of the soil, like its depth, is a matter of consequence according to the climate.  A dark soil absorbs heat, becoming hotter consequently, while it reflects but little on the plant above.  On the other hand, a light-coloured soil absorbs very little heat, but reflects almost the whole of the rays upwards upon the vine.  From this it follows that a dark soil is better in a cooler climate, because there is generally an excess of moisture; while a light colour is more suitable in the warm regions, for the moisture is then retained.

The chemical constituents of the soil play no inconsiderable part in assisting the development of the vine.  Of these, however, there are only five—­namely, nitrogen, phosphorus, potash, calcium, and iron—­ to which it is necessary to draw attention.  For the successful cultivation of wheat and other cereals a richly nitrogenous soil is invaluable; for turnips and maize one rich in phosphorus is of great advantage; but for the vine potash is of considerable importance.  It is true that nitrogen and phosphorus are necessary for the production of the vine wood, but it is for the fruit itself that the potash is so much required.  As it is well known, the deposit known as winestone or “cream of tartar,” on the inside of the cask by the fermentation of wine, is really tartrate of potash.  In a similar way the potato is a plant which requires a supply of potash, and without it there is a manifest diminution in the crop.  But in the case of the vine, unless there is a sufficiency of potash, the leaves do not attain to their full development; the stem is stunted to one-fourth of its natural size; and there is little or no fruit at all.  Calcium or lime has a marked effect in increasing the strength of the wine.  For this reason, therefore, this element is more necessary in the cooler than in the warm regions.  And finally, there is that other chemical constituent of the soil, which deserves a brief notice, and it is iron.  Now, the presence of iron therein has a distinct effect in deepening the colour of a wine.  This is without doubt the reason why our Australian wines, as a general rule, are so rich in colour.

“Cepage,” Or variety.

Many words connected with viticulture are of French origin, as might be expected considering that it is a land where the wine industry is such a source of wealth.  The term “cepage” (pronounced say-pazh) is one of these, and it possesses quite a distinctive and particular significance, so that a little explanation is necessary.  The vine family is divided into several species, of which the ordinary grape vine, Vitis VINIFERA, is the most important.  Of the Vitis VINIFERA there are many, more or less distinct, sorts of “cepages”; and the value of the word lies in the fact that it serves as a means of distinguishing all these different varieties.  Originally a native of Asia Minor, there are now over a thousand sorts of European vines.  Of these quite a number are already cultivated in Australia, and a brief reference to a few will help to a better understanding of the term “cepage.”