Note on the occurrence of traces of the heavy metals in the sandstones of the Moray Firth basin / by Wm. Mackie.

  • Mackie, William.
Date:
[1902]
Catalogue details

Licence: In copyright

Credit: Note on the occurrence of traces of the heavy metals in the sandstones of the Moray Firth basin / by Wm. Mackie. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    XXVII. Note on the Occurrence of Traces of the Heavy Metals in the Sandstones of the Moray Firth Basin. By Wm. Mackie, M.A., M.D. (Read 20th March 1902.) Some months ago in an inquiry into the possible cause of the precipitation of peroxide of manganese in the dark stains seen in some sandstones, and typically at Newton in the U.O.E. division of the Elgin sandstones, I was surprised to find that in addition to the oxide of manganese these stained areas showed notable traces of copper as well as of nickel and cobalt. Other small nodules occurring in a Triassic sandstone over- lying the Eosebrae division of the U.O.E. rocks near the Old Hospital Quarry were found to contain, in association with a relatively greater proportion of the manganese oxide, very much larger proportions of the bases indicated—CuO ’12^, oxides of nickel aud cobalt ’69%, with the addition of 1’68^ of lead calculated as PbOg or PbS. As these occurrences were ascribed to secondary local infiltration it was naturally inferred that the surrounding sandstones would if examined probably also show traces of the same metals. Accordingly determina- tions of the amount of copper oxide, and also of the nickel and cobalt oxides conjointly in a series of specimens (sixteen in all), ranoing in time from the L.O.E. of Tarradale, Culloden, and Spey Bridge through the U.O.E. division to the Triassic rocks of Cuttieshillock, Spynie and Cummingston have been made, and in not a single specimen has the copper oxide been found absent, while of the nickel and cobalt, traces of at least one and not improbably both have been found in every instance. The difficulty of effecting a separation with such minute quantities of material has necessarily prevented individual determination in all cases; but the presence of both of these metals in the manganese areas at least has been definitely ascertained. The residues in a number of the determinations have been pre- served, and from the aggregate it is intended to ascertain the . average relative proportion of the two bases.^ As regards practical details the following was tlie general routine. From 25 to 45 grammes of the powdered sandstone was extracted by boiling with strong HOI—about 40 cc. of acid being used in eacli case. The sand was then washed out with boiling (distilled) water and the finer debris separated by filtration. Soluble silica was then sepai’ated in the usual way, and HgS passed through the hot acid solution for over an hour. What precipitate formed was filtered off and repeatedly ^ These residues gave cobalt and nickel oxides in the proportion of 64 to 36.