ALEXANDRA.

Dunstan Times, Issue 941, 30 April 1880, Page 3

ALEXANDRA.

(FROM OUR OWN CORRESPONDENT.)

In concluding my remarks on this field of labour last week, I promised a fut tlier description of the dredge (Duke of Sutherland) only just lately finished and put to work by her spirited proprietors, Messrs John M'Kenzie, Fraser, and M'l.cod. As I said before, the Duke of Sutherland dredge is on the ladder and bucket principle, the motive power being the river current acting directly on to paddle wheels. The hull is 61 feet long and 10 feet beam, with a depth of hold of about 4 feet, cut away up to the bows to give her a good sheer. The current wheels are light skeletons, made of malleable iron, one and a half inches wide by abt ut five eights thick, and are thirteen feet six inches in diameter, with about four feet breast, but this, howeve’-, can be either increased or decreased to suit the current, or again, the floats, which are found to answer well, six inches wide, can be altered to suit the circumstances, and widened to twenty inches if necessary. The axle hearing the paddle wheels is a splendid piece of malleable iron about twenty-six feet long and tour inches in diameter. The ladder carrying the buckets is a description of double chain, each link being the length of the bucket, about twenty inches, and made of iron three inches wide and one inch thick, secured together by steel pins one and a half inches in diameter and a foot long, thus making the ladder fourteen inches wide. The drums supporting the ladder at each end are massive pieces of cast iron, square in shape to admit of the easy turning of the long links of the chain. The ladder is thirty-six feet long and carries twenty-five buckets, thus allowing of dredging to a depth of nineteen feet. The driving gear, which consists of two massive cog wheels four feet and three feet respectively in diameter, one fixed on the main paddle wheel shaft, the other on the upper drum of the bucket ladder, and is set in br thrown out of motion instantaneously by a lever. The buckets on the ladder are on

an entirely new principle, and are much firme” and stronger than those in ordinary use, and being steel mouthed they are expected will not only last longer but work much smoother when on rough stony ground. The ladder being fixed, put in motion, and the buckets as they ascend filled or partially filled With dirt on reaching the upper drum turn over and deposit their contents into the hopper of a large cradle, which is kept constantly in motion by one of the two men who are all that is necessary to work the dredge—tiro one as I have said to keep the cradle, in motion to assist in the disintegration of the gold from the sand, the other to look after the driving and connecting gear and regulate the angle of the ladder. The cradle is supplied with water from one of; the paddle wheels by tin buckets fitted on to the arms or spokes, each revolution, bringing up sufficient water to keep the cradle clear. As a whole the Duke of Sutherland dredging machine is a piece of work creditable alike to the designers and to the workmen, and it must be the very earnest wish of all that the enterprise of the proprietary will be rewarded to the degree they deserve. From first to last there have been a number of dredges embracing well nigh every system yet introduced, and all have worked with varying success ; but for a continuous thing those on tho ladder and bucket principle have been the moat successful, and as this the last addition embraces every improvement, and is of sufficient weight and strength to contend against any kind of gronnd she may be put to remove, there is no reason why she should not be equally or more successful than any of her predecessors. It had well nigh escaped me to mention that the whole of the ironwork was made by Messrs Kincaid and M‘Queen, of Dunedin, the name in itself a guarantee of good honest work ; but Mr M'Kenzie, the shareholder under whose supervision the whole thing was constructed, says that he is more than satisfied, “if that can well bo,” with the class of work supplied, and specially requested me, if possible, to give them the share of credit they are entitled to. I shall hope as time goes on to give an account of progress made, and should that be as it is to be hoped it will, a next duty should be to record the fact that not merely is another but that a fleet is being built; as if one will pay, there can be no reason why twenty should not pay between here aud Clyde.