66 ON THE USE OF HEATH-SOIL FOR FINE-ROOTED PLANTS. 
It can obviously act only in a mechanical way, and thongh it has been thought to 
assist in keeping the soil more open and permeable by fluids, it actually has a 
contrary effect ; for the finer the particles of earth, the more compactly will they 
set, and small sand has a powerful tendency to consolidate soil unduly into a mass. 
It is solely as a means of impoverishing soil, therefore, that it will, in a short time, 
come to be tolerated ; and this object can be accomplished so much better, or at 
least the end for which it is intended can be more satisfactorily attained, by shallow 
pots, the poorer kinds of heath-mould, and a mixture of larger fragments of sand- 
stone or potsherds. 
Regarding the value of sand for striking cuttings in, or for such like delicate 
operations, there can be little question. It is cleaner ; it more easily and thoroughly 
surrounds the base of the cuttings ; it retains moisture more equably, and is not so 
likely to cause the cutting to rot ; it does not so readily obstruct the pores at the 
severed end, and the young roots can push into it with greater facility as soon as 
they are formed. 
Returning, however, to heath-soil, we should wish to make known those of 
its properties which give it an adaptation to the particular class which is often 
distinguished by the term fine-rooted plants. Much of mistake prevails on this 
matter, and as it must necessarily determine the choice of any peculiar kind of 
heath-mould, it is the more desirable that it should be well understood. 
As a general statement, it might be sufficient to say that its suitability is purely 
mechanical, that is, it appears to depend entirely on its texture, and not on its 
chemical ingredients. Yet we mu.«t enlarge this assertion a little, and take in some 
of the details. 
Heath-soil is useful to many plants because, when good, it affords an excellent 
medium for the water to drain through. It does not, if of a proper description, 
and properly placed, become cold, sour, and sodden in the winter. The water runs 
through it, to select an exaggerated comparison, as it would through a stack of fine 
heath-branches or other small wood ; and while it leaves every part moist, it does 
not get saturated. Hence its fitness for delicate-rooted plants, which, if ever they 
were placed in a saturated medium during cold weather, and at a time when they 
could not assimilate much moisture, would lose all those numberless little rootlets 
which are indispensable to their healthy existence. 
A further and more important use of heath-mould is in furnishing a clean and 
congenial medium for the roots of certain plants to penetrate ; while it is not, like 
loam, so readily taken up in solution by water, and presented thus to the tender 
rootlets. Yegetable mould is likewise always softer than any other, and conse- 
quently more easily pierced by slender roots. And it is notorious how delicate 
fibres seem to love to insinuate themselves among other fibres, such being very 
rarely found in any soil save heath-mould. 
As heath-mould is valuable for maintaining its openness, and therefore for 
security against saturation, it is also of excellent service, for the same reason, because 
