a—2b

16

treatment with elemental sulphur at the rate of 400 lb. per acre increased the barley-yield 52 - 6 per cent,, the oat-yield 57'3 per cent., the wheat-yield 127*8 per cent., the maize-yield (variety Milo) 182'6 per cent., the potato-yield 63 per cent., and the yield of peas no less than 383'3 per cent. Substantial increases were also obtained with other crops. Treatment, with sulphuric acid equivalent to 400 lb. of sulphur per acre gave similar but on the whole lower results. Probably the experiments were made on a soil containing free alkali, and therefore peculiarly suited to the sulphur or acid treatment; but experimental work in other parts of the United States shows the value of sulphur as a fertilizer for many classes of soil, particularly when leguminous crops, such as peas, beans, clover, alfalfa, &c, are being grown. For instance, in some tests made in southern Oregon, a 500-per-cent. increase in the alfalfa cut was obtained by harrowing 300 lb. of raw sulphur into each acre. Much experimental work remains to be done in order to determine the exact value of sulphur as a fertilizer, but its addition to (he soil is known to promote the liberation of potash and the nitrification of the soil. Moreover, it has been ascertained in recent years that sulphur is much more important as a plant-food and a plant-constituent than was formerly supposed. Dr. C. B. Lipman, of the Agricultural Fixperimental Station, University of California, has shown that remarkably successful results follow the sprinkling of strong sulphuric acid at the rate of Ito 3 tons per acre on alkali soils.* It is possible that such a treatment, followed by the application of lime, may be useful in some parts of New Zealand. It is certain that the bold conception of the use of a strong mineral acid, first made, or at least first practically tested, in California, will bear important results in regions with arid soils, such as those of North aud South Africa, Persia, parts of India, parts of Australia, &c. 20. BATON RIVER FLUOR-SPAR. On the 3nd June, 1889, Professor James Park, then Assistant Geologist, discovered a deposit of fluor-spar in the Baton River district, and later he described it in a report entitled " On the Occurrence of Fluor-spar at the Baton Goldfield, Nelson," which appeared in Reports of Geological Explorations during 1888-89, No. 20, 1890, pp. 73-74. The largest outcrop, according to Park, is 60 ft. long, 30 ft. to 35 ft. wide, and forms a spur 8 ft. to 20 ft. high. Fluor-spar can be traced by loose blocks for a quarter of a mile, and is again visible farther to the south-south-west near some limestone caves. Park mentioned barite and other minerals as associated with the fluor-spar. He quoted no analysis, but subsequent to the publication of his report a sample was analysed by Mr. W. Skey, who reported 52 p 43 per cent, of sulphate of barium (barite), 35*21 per cent, of fluoride of calcium (fluorite), and 12'36 per cent, of quartz, f In April, 1916, Mr. T. O. Bishop, Inspector of Mines, Reefton, after considerable search, relocated the fluor-spar deposit on land now owned by Mr. C. H. Faulkner. He reported thai, the outcrops occurred on the north face of what is locally known as Thomson's Hill, about halfway between the Wangapeka and Baton rivers, and could be reached by half an hour's climb up a steep hillside from the main road. Wherever examined the fluor-spar was found to be largely mixed with barite and quartz. A sample taken by Mr. Bishop was submitted to the Dominion Analyst, who reports as follows : — " Calcium fluoride (CaFJ .. .. . . .. .. .. 46-20 Barium sulphate (BaSO J .. .. .. .. .. 27-10 Silica (Sio 2 ) .. .. .. .. .. .. ..21-40 Alumina (A1 2 0,) .. .. .. .. .. .. .. 1-50 Iron oxide (Fe 2 'o :! ) .. .. .. .. .. .. .. 1-30 Loss in ignition .. .. .. .. .. .. .. 2-50 I 0-00 " The sample was ground to pass a 60-mesh sieve, and separated by panning into three portions, A, B, aud C, which were analysed separately, with the following results : — Percentage Barium Calcium of Whole. Sulphate. Fluoride. Silica, Ao. " A (heaviest portion) .. .. 20 62-5 25-0 12-5 B (intermediate portion) . . .. 30 22-0 60-0 18"0 C (lightest portion) .. .. 42 12-0 ' 50-0 38-0 Loss .. .. .. ..8 " These results show that the silica tends to remain with the fluor-spar, and is not readily separated by water-concentration. This would greatly detract from the commercial value of the mineral. " J. S. Maolauriin, D.Sc, F.C.S., " Dominion Analyst." The reports quoted and Dr. Maclaurin's tests as given above show that the prospect of obtaining a commercial grade of fluor-spar from the Baton River deposits so far as yet explored is small. The material, however, may have some value in the manufacture of pottery and glass.

* See "Sulphuric Acid for Alkali Land." Mining and Scientific Press, 12th May, 1917, vol. 114, pp. 046-647. t 26th A in. Rep. 001. Mus. and Lab., 1892, p. 31.