The Quarterly journal of the Geological Society of London . this occasion to bring but one before the notice of the Society ; theresults obtained by it are so positive and striking that there can beno reason for delaying their publication. A rectangular trough, measuring internally 6 cm. in width,6 cm. in depth, and 30 cm. in length, was made of wood; it wasclosed at one end, and so constructed that by the removal of somescrews it would readily fall into halves along a median longitudinalsection. A barrier of wood 23 mm. in height and 20 mm. inbreadth extended completely across the trough at a
The Quarterly journal of the Geological Society of London . this occasion to bring but one before the notice of the Society ; theresults obtained by it are so positive and striking that there can beno reason for delaying their publication. A rectangular trough, measuring internally 6 cm. in width,6 cm. in depth, and 30 cm. in length, was made of wood; it wasclosed at one end, and so constructed that by the removal of somescrews it would readily fall into halves along a median longitudinalsection. A barrier of wood 23 mm. in height and 20 mm. inbreadth extended completely across the trough at a distance of115 mm. from the closed end (fig. 3, p. 364). The trough was placed in position for charging with cobblerswax—perhaps for the sake of brevity we may be allowed to callthis pitch —by raising it at the open end, so as to give it a tiltof nearly 12°. The pitch, melted by boiling it in a glue-pot arrangement,was then poured in up to the level 1 (fig. 1); it was allowed time Fig. 1.—The pitch ?glacier at the commencement of the 1, 2, 3=layers within the pitch having an uniform slope of 11° or 12°. 4=original surface of the glacier. The lines to the right of thisrepresent the contours of succeeding surfaces in later stages ofthe experiment. to solidify and then covered with an even layer of crystals of sugar,a substance which subsequent experience proved should be avoidedin these experiments. Fresh material was poured in till the level 2was reached, and on solidification an uniform layer of sago wasspread over it. A third stratum of pitch was now added, and itssurface thickly dusted with powdered vermilion ; a last layer ofpitch poured over this rose to the edge of the closed end of thetrough on the one hand, and on the other just overbrimmed thesummit of the transverse barrier. When the whole had cooled tothe temperature of the room, the trough was untilted, and set torest with its sole in a horizontal position. The upper surface ofthe wedge of pitc
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Keywords: ., bookcentury1800, bookdecade1840, bookidquarte, booksubjectgeology
