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broad stone pavements, whenever he came just under any of the 
sign-irons, his cane gave a different sound, and occasioned a diffe- 
rent kind of resistance to the hand, from what it did elsewhere ; and- 
attending more particularly to this circumstance, he found, that 
every where, under the drip of those irons, the stones had acquired 
a greater degree of solidity, and a wonderful hardness, so as to resist 
any ordinary tool ; and gave, when struck upon, a metallic sound : 
and this fact, by repeated observations, he was at length most tho- 
roughly convinced of. This observation of the Doctor’s was illus- 
trated by some experiments, in which he ascertained, that, by thus 
washing frequently pieces of Portland- stone with water impregnated 
with rusty iron, they acquired a very sensible degree of the hardness 
here described, and on being struck gave the metallic sound. — Part 
of a horse-shoe was seen by the Doctor, on the sea-coast, near Scar- 
borough, incrusted with sea-sand ; and, although the sand was but 
little tinctured with an ochry colour from the iron, it had acquired 
the hardness of common grit-stone.” 
Part of a ladder, with some of the steps, which Mr. Baillou, of 
Florence, presented to the Emperor, and which was placed in the 
Imperial Museum at Vienna, was most probably merely an incrus- 
tation ; similar incrustations of ladders, &c. frequently occurring at 
the incrustating springs in this kingdom : and Italy, from whence 
it appears this cabinet specimen was sent, as we have already seen, 
abounds with waters possessing this quality. Several authors relate 
that formerly the handles of hatchets, &c. were found in a petrified 
state. But it should be considered, that formerly, also, the arrow- 
heads and stone hatchets of the aborigines of some parts of Ger- 
many, not very dissimdar from those we now receive from the South 
Seas, were regarded as thunderbolts. Thus Lachmund says, the 
Ceuavnia, Ceraunius Lapis, Lonner stein, an^Donnerkeil, 
were given to those stones which had fallen from the clouds at the 
time of thunder, and which resemble hammers, hatchets, wedges, &c. 
