. The Iron and steel magazine. ith the decaying vegetable matter whichgrows rank in the marshy lands, carrying with it quantities ofthe sand, saturated with iron oxide. The organic acids evolvedby the decomposition of the vegetable stuff dissolve the oxideof iron, which is carried to the lake. But as it floats down, thissolution of protoxide of iron is acted upon by the atmospheric air,oxidation takes place and a remarkable phenomenon is per-ceived. Patches of iridescent film appear on the surface ofthe lake, looking like petroleum with its rainbow colors, indi-cating that the soluble protoxid
. The Iron and steel magazine. ith the decaying vegetable matter whichgrows rank in the marshy lands, carrying with it quantities ofthe sand, saturated with iron oxide. The organic acids evolvedby the decomposition of the vegetable stuff dissolve the oxideof iron, which is carried to the lake. But as it floats down, thissolution of protoxide of iron is acted upon by the atmospheric air,oxidation takes place and a remarkable phenomenon is per-ceived. Patches of iridescent film appear on the surface ofthe lake, looking like petroleum with its rainbow colors, indi-cating that the soluble protoxide has been transformed into in-soluble sesquioxide of iron. The reason this peroxide film appearsin patches is due to concentrationary action; the particlesaggregate themselves into batches, which sink to the bottomof the lake in the form of cakes ranging up to ten inches diam-eter or more; hence the term cake ore. This brown hematite lake ore contains 70 per cent ofmetallic iron, and seems inexhaustible; for with the decay of. o On 3o8 The Iron and Steel Magazine each years vegetation, new supplies of iron from the sands aredeposited in the lake. These rich lake ores have been used inthe St. Maurice furnace at Radnor since 1752. In 1775 one ofthe lessees of the Radnor furnace aided the American colonistsby casting shot and shell — made from the lake ores — to beused against Quebec. Lac a la Tortue and a neighboring lake are the only knowninstances of the kind on the American continent. Deep mine formations like those of the Chap in Mine, andlake bottom deposits similar to that of Lac a la Tortue, are,however, mineralogical curiosities when compared with themagnificent surface deposits of the Mesabi range in Lake Supe-rior country. We are almost bewildered with the marvellousprodigality of nature when we look upon awe-inspiring sceneslike that pictured in Fig. 4. Gazing upon this stupendous workof man, we are impressed with the same sense of grandeur andmajesty as we are up
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectiron, bookyear1898
