"—Sabinos petit aliquanto tristior, quod sacrificanti hostia aufugerat: quodque tempestate serena tonuerat."
Sueton. Tit. cap. 10.
[45] This letter was not received by Dr. Maty in its present form: and is rather the substance of an explanatory catalogue, which was sent to that gentleman with sundry specimens of the different materials that compose the soil described in the preceding [letter]; which catalogue remains, with the specimens, in the Museum of the Royal Society, for the inspection, and, I flatter myself, the satisfaction, of the curious in natural history.
[46] See [p. 103] of this collection.
[47] See [Letter I.] [p. 18.]
[48] Having heard the same remark with respect to the lava's of Vesuvius, I determined, during an eruption of that Volcano, to watch the progress of a current of lava, and I was soon enabled to comprehend this seeming phænomenon; though it is, I fear, very difficult to explain. Certain it is, that the lava's, whilst in their most fluid state, follow always the law of other fluids; but when at a great distance from their source, and consequently incumbered with scoriæ and cinders, the air likewise having rendered their outward coat tough, they will sometimes (as I have seen) be forced up a short ascent, the fresh matter pushing forward that which went before it, and the exterior parts of the lava acting always as conductors (or pipes, if I may be allowed the expression), for the interior parts, that have retained their fluidity by not having been exposed to the air.
[49] The flames Lord Winchelsea mentions, were certainly produced by the lava having met with trees in the way; or perhaps his Lordship may have mistaken the white smoak which constantly rises from a lava (and in the night is tinged by the reflection of the red hot matter), for flame, of which indeed it has greatly the appearance at a distance. I have observed upon Mount Vesuvius, that, soon after a lava has borne down and burned a tree, a bright flame issues from its surface; otherwise I have never seen any flame attending an eruption.
THE END.