NEW ZEALAND POTASH.

Taranaki Daily News, 31 January 1917, Page 3

NEW ZEALAND POTASH.

MR, A. 1). BULL'S SCHEME. VIEWS OP EMINENT SCIENTISTS London, Dec. !>. Mr. A. D. Ball's article on tlic prevalence of potash in the schist rocks of Of ago was quoted recently by the Hii;h Commissioner in a letter to The Time?. Mr. Bell stated that Mr. B. C. Aston, chemist to thc-Agricnltural Department, had established the fact that mica schist formations of the South Islai'td contain cd on an average 3 per cent, of potafh. "That is only another way of saying," said Mr. Bell, 'that over vast area? of Otago alone there arc literally niilliriwt of tons of pure potash to the sq.iare mile. The rock which contains it i.i probably the easiest mineral to ir.'nw in the whole world. It is comparatively soft to crush when the blocks aro brought down to tho mill, and Mr. Aston says he knows of vast deposits actually already in a state of powd.'r." Mr. Bell expressed the (.'wiioii that; the Stassfnrt mill'.' in Germany .would kok. beside the mica 6chists of Otapo, something like a bottle on a druggist's shelf. This statement lias brought some comments from scientific quarters. Dr. J. A. Voelck»r, Consulting Chemist to tlit Koyal Agricultural Society of Ensland, says, in criticism, that the difficulty is the insoluble nature of the compounds, which decompose so slowly that the potash becomes only very gradually available for plant use. "Moreo\er," he ad;U, "there has not been found any process by which the potash contained in these refractory materials car be coinmerchilly- extracted. Since the year 1011 I have been experimcntii.g, at the Royal Society's farm at Woburn, on felspars, granites, plionolit, etc., in order to see whether, when very finely ground, either alone or in combination with other materials, such f>s lime, salt, etc., they would yield np tl.eir potash for the benefit of plants But so far there has been no indication of success. A much more hopeful source of potash supply is at hand, I tl.ink, in the recently-discovered deposits of potash salts in the North of Spain. Wh.it is necessary is for our Government to urge upon the Spanish Government the pressing need for setting these supplies free."

Mr. Wyndlmm E. Dunstan, F. 8.5.. Director of th? Imperial Institute, says that as a matter or fact there is nol in view at present any deposit of potash in any country of the Empire comparable in nature, extent, or value with thr.H of Stassfurt, 011 which virtually the whole world lias hitherto depended for agricultural and for some industrial purposes. The potash is mica schist, unl'k'e that of Stassfurt, is not soluble 111 water, and no commercial means as yet have been devifed of extracting soluble potash from mica schist. But Mr. Dunstan says that mica sc-hist is promising at present from quite a different point of view. His ".uggistion is that powdered minerals containing insoluible potash might be sppl.'ed direct to soils poor in this constituent, since it is probable that the potash would be slowly liberated in a soluble form, and thus become available for plant food. "If this suggestion should prove to be successful with mica schist or ot'r.er similar minerals, agriculture in New Zealand, as well as in other countries, would not in future be entirely dependent on supplies of j potash procured from Germany."