in his Paper on a saline Substance from Mount Vesuvius. 135 
Desirous to know also in what state was the matter thus 
thrown up very high, and falling in showers, he followed with 
the sight some of the largest masses ; and observing in what part 
of the crater they fell, he hastened there before another explo- 
sion: he found that they were come out very soft; for the 
largest, preserving longer their heat in their way through the 
air, were flattened like cakes ; but the smaller masses, though 
still red-hot, had preserved their various forms. , 
It is from these ejections, carried out of the circumference of 
the crater in different directions by strong winds, that are formed 
the slopes of loose cinders which make the ascent to the traler 
very difficult, because they slide under the feet : those, therefore, 
who are not used to climb on all kinds of mountains, aré obliged 
to employ some men, ready there for that purpose. “These men 
have a belt, with a loop ef string fixed to it, taken hold of by. 
the people who could not ascend without help, who are thus 
dragged up. ‘ 
But my brother, used to climh the slopes of rubbish in’ the. 
Alps, which oppose the same difficulty as those of cinders, judg~ 
ing that on the slopes of cinders might be fuund all the kinds of 
ejections from the crater of Vesuvius, waiked over them at diffe- 
rent times in different directions, with expectation that they might 
lead to some knowledge both of the depth from which they pro- 
ceeded, and of the kind of mineral strata through which they 
burst. He was net disappointed in that hope: for he found 
among the cinders large fragments of granite, sienite, of several 
kinds of quartzeous stone, and of hard limestone ; all of which 
belonging to the lowermost known strata, indicate clearly that 
the substance of which /ava is formed lies under those strata. 
Thus, when the real phenomena are attentively studied, nothing 
is left for the work of imagination. {s it permitted in presence 
of common sense te form general systems, from particular phe- 
nomena? Had the author considered this, he could not have 
supposed that a particular saline substance found on the slope of 
Vesuvius could lead to conclude that the internal part of the 
globe shows it to be an extinct sun or comet ; while the ejections 
of that volcano demonstrate that the dava is formed under known 
mineral strata in whieh no sign of igneous operation is discovered, 
Another great fact, with which the author appears to be totally 
unacquainted, though I have described it with all its cireum- 
stances in the abovementioned work, Histoire de la Terre et de 
Ll’ Homme, is this: On the surface of our continents rise many 
volcanic eminences, showing indubitable characters of having been 
produced on the bed of the sea before it became our continents. 
That great gedlogical fact of our continents having been for- 
merlv the bed of the sea, so contrary to the author’s system, is 
2 14 demon- 
