Penny Blood: Serial Sensation and Working-Class Entertainment — page 266: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

CHAPTER XX. SEQUENCE OF VOLCANIC ROCKS. Flow of matter melted off roots of mountains—Force causing it considerable— Formation of lavas—These will differ in different areas and at different times—Law of Bunsen—Richthofen’s ‘* Natural System of Volcanic Rocks” —How explained by him—Dificulty arising—Captain Dutton’s explanation —Prof. Judd on Richthofen’s System—Melting of roots of the mountains affords an explanation of the sequence—And of the variation of volcanic products in adjacent regions. IT has been already remarked that, where the roots of the mountains project downwards into the hot fluid substratum, they must be slowly and gradually becoming fused’, The material that becomes fused is derived from the crust, which is of less specific gravity than the substratum, and it must be like- wise remembered that the roots of the mountain extend down- wards to a considerable depth, perhaps 10 times the height of the upper mountain, into the substratum, which will be more dense in its lower layers. The consequence of this must be, that the fused rock which is melted off the roots will have a tendency to flow upwards, and to accumulate along the under side of the crust much in the same way that lava, coming from a vent, runs down a mountain’s side, and spreads itself out upon the surface. We must in the present case, as it were, invert our ideas of the usual movement of a liquid mass. The fused rock which runs up these roots will not be -cooled as subaerial lava is, but will retain its liquidity. On the other hand, moving in a medium about as dense as itself, its motion will be very 1p, 152. CONNEC OOO @ (CO)