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…Soot; in other, as if with Lime, according to the complexion of the several Minerals. The flames do many times shift places, abandoning the old, and making new Eruptions (the mouths of the vents invironed with yellow cinders) arising with so strong a vapour, that Stones thrown in, are forthwith ejected. Yet for all these terrors, it is hourly trod upon…
https://www.wichita.edu/academics/fairmount_las/geology/wparcell/Kircher/volcanoes/chapter5.php