0.—3

52

Among the first improvements that will be made in the gold-saving appliances in use on dredges will be the addition to every dredge of a perfect distributer. The width of the tables will also be increased, especially when the dredge is designed to treat gravels known to contain very fine or scaly gold. Mechanical engineers will also find it advantageous to vary the construction of dredges designed to work gravels covered with a thick layer of tenacious clay, to enable the stripping to be done and the spoil elevated without being washed through the screen, especially where the water-supply is limited. Upon some of the valley deposits a specially constructed dredge to do the stripping alone might even be profitable. With the large spread of tables required for beach-sands, the ingenuity of the inventor may be directed to the necessity of making the mats used on the tables self-washing, as in the Prue and Triumph vanners. When working on beach deposits the problem of preventing the dredged material from running back into the dredging basin or paddock in the form of a quicksand has yet to be solved. It is frequently remarked that dredging as an industry is yet in its infancy, and the same may be said with equal truth of the dredges. Eegarding the efficiency of the men employed, successful dredging depends greatly upon the skill of the winchman. A dexterous winchman has gained his knowledge by experience. The art of handling a dredge properly and keeping the buckets to the face so as to lift to the best advantage cannot be learned from precept. The demand for competent hands is so constant, not only to supply local wants, but also for manning machines in the Australian Colonies, that a man qualified to handle the winches of a dredge adroitly can readily obtain an appointment, and will naturally sell his knowledge to the highest bidder. It thus frequently happens that there is only one expert winchman besides the manager and two men gaining experience on a dredging staff. The class of men who are taking up gold-dredging in New Zealand are of the right stamp, and able to use their brains as well as their hands. The present lack of skilled labour will therefore come to an end in a few years.

SCHEELITE. Scheelite (tungstate of lime) is found associated with quartz in the Otago Lake District, at Macrae's, and in Marlborough. The only place at which it is being commercially worked is at the mine of Messrs. Donaldson Brothers, Macrae's, Otago, where the scheelite is separated from the crushed quartz by concentration. About 100 tons have been shipped to Europe during the year. The yield of tungstic acid is about 67 per cent. This acid is used in the manufacture of steel for armour-plates and ordnance, also for rendering fibrous and textile materials non-inflammable. It has recently been reported that a discovery of scheelite of good commercial value has been made near Bendigo, Otago.

CINNABAE. A sample of ore sent me by Mr. T. W. Bruce, of Inchbonnie, which he had obtained from near the Seven-mile, Taipo, was submitted to Mr. Skey for analysis. Mr. Skey reports the following results:— Per Cent. Cinnabar ... ... ... ... ... ... ... 91-88 Haematite ... ... ... ... ... ... ... 6-83 Siliceous matters ... ... ... ... ... ... 1-29 100-00 yielding 79-2 per cent, of mercury. A discovery of this mineral has also been made between Waipori and Waitahuna, Otago. Examination on behalf of the parties interested has shown that there are good grounds for recommending thorough and systematic prospecting operations.

OIL-SHALE. Although the existence of oil-shale deposits in various parts of the colony has been known for several years, nothing has been done to develop any of them until recently. The deposits at Orepuki have been leased by an English company, and extensive works are now in course of erection under the supervision of Mr. Bobert Dunlop, a gentleman of high scientific attainments, who has had a lengthy experience as manager of similar works in Scotland. Mr. M. Straw is mine-manager. I have also to thank Mr. Dunlop for the following paper on the working of oil-shale :— " The oil industry in Britain extends away back into the seventeenth century, as in the year 1694 a patent was granted for the production of pitch, tar, and oyle (oil) out of a kind of stone. Very little progress was made, however, until the year 1781, in which year the Earl of Dundonald (of whom the Dundonald of Boer fame is a lineal descendant) discovered how to make oil and tar from a kind of coal. He carried on his destructive distillation in ovens or retorts very similar to