Fascine mattresses, to prevent slips and subsidence in an embankment in very soft ground, such as loose sand, are to be recommended, and experienced engineers have expressed their belief that they are the best means of procuring a firm foundation and securing it from scour in loose sandy and soft deposits; and their employment may become necessary when the earth is very wet, and the contour of the district renders effective drainage or consolidation of the soil difficult or impracticable. Should the ground after drainage be only damp, brushwood, or heather, so laid as to offer the firmest and most even bed may be sufficient; and if sand can be used with it, it is very advantageous; but the fascine or a more solid method of distributing weight may have to be adopted. Fascines should be laid over the whole base of an embankment and extend some little distance upon each side, beyond the toe of the slope, and be made stronger according to the load they have to support, which, of course, increases towards the centre of an embankment, where it is greatest, in order to prevent their breaking apart and becoming detached. In peaty soils an embankment should be formed of light dry materials, be spread out, have equal bearing, and be of as little height as possible, and all hollows and depressions should be carefully filled. The worst state of peaty or bog soils upon which an embankment has to be tipped is when they are no better than a floating mass. Where a stratum of sound firm soil, such as gravel, lies upon a soft bed of great depth, by increasing the bearing area upon the firm earth and not interfering with it, a stable foundation for an embankment may be obtained. In such a case a cutting should be avoided, for if care be taken not to impair or injure the firm top layer it may stand without serious subsidence, but under other conditions it would be unstable, and when a soft stratum is affected and its natural condition altered, it may be very difficult to restore it to a state of permanent equilibrium in consequence of it being in almost a constant state of mutation. CHAPTER IX. THE DEPOSITION OF AN EMBANKMENT.—PREPARATION OF THE GROUND UPON WHICH AN EMBANKMENT HAS TO BE DEPOSITED.—METHODS OF PROCEDURE.—CONSIDERATION OF SOME OF THE DIFFERENT SYSTEMS.—THE EFFECT OF THE HEIGHT OF A TIP AND THE LENGTH OF A LEAD.—THE STEAM NAVVY AND EMBANKMENTS.