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Watt and Nisbet's Patent Stopfer for the Prevention of Losing of Buckets on Dredges. This is a simple contrivance set upon a bucket-ladder of a dredge, placed at right angles with the ladder, and consists of a shaft working in three bearings. On the shaft are secured two " bell-crank " levers, having a light and a heavy end. These crank levers are so placed on the shaft as to come exactly between the connecting-links, and in a line with the centre of the bucket-link. The light end of the bell-crank being uppermost and working against the under-side of the bucket-link, the lower or heavy end of the bell-crank is made sufficiently heavy to bring it to a position of rest as shown in full lines on plan. When in this position it will arrest the runaway buckets before they have travelled more than 8 in. or 10 in. The dotted lines show the chain of buckets having travelled a distance of 8 in., and it will be seen that the bell-crank has assumed a horizontal position, and is on the point of release from the bucket-links. There should not be less than two sets placed on each ladder, so that one set will always be in position to arrest the runaway buckets. The arresters are placed in the centre of the ladder and at or near the lower end ; the centre ladderroller must be a flanged one, so as to guide the bucket-chain centrally. By reference to the plan it will be easily seen that the " tumblers " or " cranks " shown in full lines are at rest, and shown in dotted lines, marked, not only the advance of the buckets, but the tumblers on the point of release, the buckets having advanced that distance. A set further up the ladder would be at the point of release at the end of the bucket-link, and the set lower down would just be coming into contact with the front end of the bucket-link. By this means there is always one in position to arrest the buckets; but, should the chain break, one or more will immediately fly into position. There are disengaging-levers not shown on the plan, these levers are to disengage any one or all of the bell-crank tumblers. They are placed within easy reach of the winchman. Gillespie's Dredging-link Shoe. Mr. Thomas Gillespie, dredgemaster of the Happy Valley Dredge, Happy Valley, Lawrence, Otago, has patented a very simple arrangement by which the working-life of an ordinary dredge-bucket "runner" can be greatly prolonged, and at the same time effect considerable diminution in the ordinary costs of repairs. Hitherto, the bucket runners have been subjected to enormous friction, and when somewhat worn down have been reversed until worn down at the other side to such an extent as to become useless. By the adoption of the improvement under notice, the runner itself is relieved from wear by a shoe of § in. angle steel, secured to the runner by a couple of rivets, which are easily removable when it is necessary to remove the old shoe and substitute a new one. In the case of old buckets which have been at work in the ordinary way, shoes of angle steel can be fitted to cover the worn part of the runner, which thus becomes virtually equal to new. It is claimed that the cost of fitting a set of buckets with these shoes is not a quarter of the cost of replacing a full set of runners, and also that the loss of time in fitting or renewing the shoes is trifling compared with that of entirely renewing a set of runners, thus effecting a double saving. This invention was brought under my notice at my last visit to Lawrence; and I understand the invention has been adopted on some of the dredges in the locality, and has given entire satisfaction.

Restoration of Land after being worked by Gold-dredges.

Mr. P. W. Payne, Consulting Engineer, Dunedin, has kindly supplied a drawing and description of a dredge (Knewstubbs' system) so designed as to strip off the surface soil, &c, overlying the gravel wash in advance of the dredging-work proper and to deposit the soil on the tailings well behind the dredge. The invention comprises a new form of sluice-box, for which patent rights have been applied. The replacement of the top soil or overburden on the gravel is carried out by a simple arrangement of combined sluice-box and soil-shoots, as shown in plan. The two outside shoots carry the soil, and these, being longer than the sluice-box, convey the soil to a much greater distance than the tailings, and naturally deposit the soil on the top of the latter. In working the dredge, operations are conducted alternately in the soil and the gravel, the work of stripping being carried on without lifting the auriferous gravel. The drawing shows the dredge in a position ready for receiving the buckets to strip the top soil to a depth just sufficient to allow flotation of the pontoons. Stripping is carried on across the whole width of the paddock-face and as far forward as the buckets can conveniently work, the soil being carried over and deposited on the gravel-tailings by means of the soil-shoots until the point B is reached. The dredge is then dropped back and the gravel-wash dredged separately.

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