A piece of stone from the old church of St.Hilaire is exhibited, which, when struck, emits so horrible an effluvia as to render it unapproachable.

The church is said to have been built of this stone; if so, the workmen must have been considerably annoyed while constructing it, and deserved _indulgences_ for their perseverance in continuing their labour.

It would appear that this is a calcareous[5] rock, which has been described by several French naturalists who have met with it in the Pyrenees, at the Breche de Roland, and on the height of Mont Perdu, and whose odour of _sulphureous hydrogen_ is supposed to arise from the animal matter enclosed in its recesses.

Some marbles have the same exhalation, yet are employed in furniture: as the smell does not appear to be offensive unless the stone is struck with some force, it may, perhaps, be unobserved; but I could scarcely regret that the church of St.Hilaire was almost totally destroyed when I heard that such disagreeable materials entered into its construction.

No doubt the presence of the arch-enemy was considered as the cause of this singular effluvia in early times, and the monks turned it, as they did all accidents, to good account.
[Footnote 5: Calcaire hepathique.