H.—34

Of the original five sheep on the control area, one died in. May, 1942, and two others were very weak. These wtere drenched with cobalt and soon became strong again. The following summary gives the average live weights at different periods:—

These figures show that small applications of cobalt sulphate are beneficial on this deficient, area and that the 4oz. application has kept the stock in good condition over nearly two seasons. The cobaltized superphosphate has again given outstanding results. The wool weights are instructive in showing the superiority of the cobaltized-superphosphate treatment. Analysis for cobalt, content of the pastures of the above areas has shown that the effect of' the cobaltized-superphosphate application is still very marked; changes in the cobalt content of the pastures of the other plots have been found to correlate with the live weights of the animals. At Glenhope in the 1939-40 season a trial was run in which sheep were depastured on a cobalt-deficient area until symptoms of bush sickness appeared, after which the animals were treated with cobalt chloride at the rate of 8 mg. of cobalt weekly. Periodically animals were slaughtered and samples of blood, liver, spleen, heart, kidneys, and pancreas were obtained for analysis. The necessary analyses have now been completed, _ and show that as the animals become progressively bush sick so the cobalt content of all these decreases continuously. After drenching began, the cobalt contents increased greatly. Three weeks after the treatment was commenced, except for the spleen, the cobalt contents were almost as high as after four months of treatment. Pasture Top-dressing Trials The Use of Serpentine-derived SodSampling of the areas treated with 5 cwt. and 10 cwt. of a Nelson soil derived from serpentine and carrying approximately 350 p.p.m. of cobalt in February, 1940, has been continued. These applications of soil still (December, .1942) exert an effect sufficient to maintain the cobalt, content of the pasture at a level satisfactory for stock health. Use of Cobalt Compounds' with Ground Limestone as Carrier The plots top-dressed last season with mixtures of ground limestone and cobalt carbonate, hvdroxide, phosphate, and sulphate have been continued into this season. Ground limestone used alone continues to slightly depress the cobalt content of the pasture. Applications of cobalt compounds equivalent to 10 oz. cobalt sulphate per acre generally show good increases, especially for cobalt phosphate. The uptake of cobalt by the pasture has therefore been satisfactory ifrx the presence of the ground Limestone. Mowing Trial Samples of pasture from these trials have been analysed for cobalt. Serpentine superphosphate at 3 cwt. per acre showed a very fleeting effect in_ increasing the cobalt content. Addition of magnesium carbonate or sulphate to the fertilizer did not affect the cobalt content of the pasture in either season of the experiment. Molybdenum in Soils and, Pasture In view of statements in Great Britain that use of cobalt salts or of ground limestone increased the molybdenum intake by a pasture, determinations of molybdenum content were, made on a number of pasture samples from previous experiments where cobalt salts had been used for top-dressing. Even where 1 cwt. of cobalt chloride per acre had been used only slight increase in molybdenum content was found. Ground limestone showed no definite effect. In these New Zealand samples the molybdenum content hardly ever exceeded 1 p.p.m. of the dry matter. MINERAL RESOURCES COMMITTEE Personnel —Dr. E. Marsden (Chairman), Mr. C. 11. Benney (Deputy Chairman), Mr R L Andrew, Mr. W. M. C. Denham, M.P., Mr. W. Donovan, Dr. J. Henderson, Mr. e! O. Macphcrson, Mr. F. J. A. Brogan (Secretary). The Committee continued to supervise and co-ordinate field surveys and laboratory investigations of mineral resources, especially those of war importance, carried out by the Geological Survey, Dominion Laboratory, and Mines Department. Four meetings were held during the year. Mica.—A further examination was made of mica occurrences located by the Geological Survey in South Westland, in which representatives of the Mines Department, Geological Survey and a company interested in the development of non-metallic minerals participated. The results were disappointing in that the quantity of mica likely to be recoverable was insufficient to interest commercial enterprise, and its average size was below the minimum marketable size specified by the British Government. Difficulty of access is another adverse factor. Nevertheless, representative samples were sent to the British Government for examination and report as a guide to further investigations. Another mica occurrence

11

April, 1942. August, 1042. Jannary, 1942. I nece^ 0 e „j 1942 ' lb. lb. lb. lb. Control 88-8 •• 97 ' 6 8 ' 2 2 oz. cobalt sulphate .. .. •• 101-8 99-4 140-4 9-9 4oz. cobalt sulphate .. .. ■■ ■■ 106-6 i?'? 2 t Cobaltized superphosphate .. .. •• 122-0 131*2 l(>o-2