DIATOMACEOUS AND SILICEOUS EARTHS.

New Zealand Journal of Agriculture, Volume XX, Issue 3, 20 March 1920, Page 208

DIATOMACEOUS AND SILICEOUS EARTHS.

During the past few years the writer has examined several specimens of diatomaceous or pure siliceous earths. In 1917 some excellent samples were sent in. The origin of these siliceous earths was difficult to account for, owing to the absence of any evidence of organized structure. Some specimens were submitted to New Zealand manufacturing firms, who reported favourably upon the material, and stated their willingness to adopt it in place of material which they had hitherto imported. The matter was mentioned in the annual reports for the years ending 31st March, 1917 and 1918. Since then some additional samples have been dealt with, and some have been utilized in glue-making and in one other industry which previously imported its kieselguhr or diatomaceous earth. Recently other material of this nature has been received, and on examination disclosed clearly the minute siliceous remains of a low form of life.

The position, therefore, appears to be that excellent samples of diatomaceous earth are available in widely scattered localities throughout the Dominion, and it is advisable that an endeavour should be made to utilize the more accessible deposits. Supplies of this material imported cost several pounds a ton, and in these days of high freights it might pay to give preference to the local supplies. This diatomaceous earth has many applications in the manufactures, and is used in glue-factories for filtering. It would probably be valuable as an insulatingmaterial —very likely superior to pumice. It has also been used as an absorbent for nitro-glycerine in the manufacture of explosives. The Department would be pleased to supply to any inquirers the names of those who have sent in samples of these earths.— B. C. Aston.