XIV. On the Action of Organic Matter on Peroxide of Iron, as observed in the Post-Tertiary Sands of Glasgow

Abstract

Having visited, last summer, the excavations at Stobcross for the New Docks, I made a few observations which may be interesting to those who study chemical geology. Underneath a few feet of ordinary brown river sand, containing hazel nuts, and fragments of decayed wood, a dark-coloured bed of sand, charged with vegetable matter, occurs. This dark-coloured sand had a disagreeable smell, gave no effervescence with hydrochloric acid, but on gently heating, the odour of sulphuretted hydrogen was at once perceptible. The acid solution contained protoxide of iron, alumina, a little lime, and a considerable quantity of magnesia. The iron existed as mono-sulphide. When treated with water, the sand gave up a little sulphate of lime. The sulphuric acid, and the sulphur existing as sulphide of iron were estimated in a portion of the sand previously dried at 100° c. The sulphuric acid would be equal to .21 p.c. of sulphate of lime (Ca″ SO 4 2 Aq.) and the sulphur equal to 4.09 p.c. of the monosulphide of iron (Fe S.) Some of the twigs freed from extraneous matter by washing, left a residue of peroxide of iron when burned, the iron existing originally as sulphide. Two oak trees which had been turned up by the workmen, were quite black exteriorly, and had an intensely styptic taste. A portion boiled with water, gave a solution very acid to test paper, and containing free sulphuric acid and sulphate of iron. The sulphate of iron and This 250-word extract was created in the absence of an abstract