against the Stone. They have a big head, somewhat flat, and even, of the
colour of a Tortoise-Shell, braunish, with some small white hair. Their
mouth is also big; where may be seen four kinds of Jaw-bones, lying
crossewise, which they move continually, opening and shutting them like a
pair of _Compasses_, with four branches. The Jaws on both sides of the
mouth are all black, the nether Jaw hath a point like the Sting of a Bee,
but uniform. They draw threds out of their mouth with their fore-feet,
using that point to range them, and to form their Shells of them. They have
Ten Eyes, very black and round, which appear to be bigger than a Pins head.
There are five of them on each side of the head, standing after this
manner,

[Illustration]

But besides these Worms, I have found, that _Mortar_ is eaten by an
infinite number of small Creatures, of the bigness of Chees-Mites. These
have but two Eyes, and are blackish. They have four feet on each side
pretty long. The point of their Muzzle is very sharp, as that of a Spider.
I send you but one of them, though I had abundance, but they are dead and
lost. It may be, you'l find some at _Paris_, seeing that in the old Mortar
betwixt Stones, that is found in Walls made with rubbish, there is great
store of them, together with great plenty of their little Eggs. I have not
yet examined, whether these be those, that in the surfaces of all the
Stones, where they are met with, make little round holes, and small traces
and impressions, which make them look like _Worm-eaten Wood_. But 'tis
probable, they are such. It should be observed, whether these Worms do not
take Wings, and all the other appearances of Caterpillars; and whether they
are not to be found in plaister that is full of holes, in Bricks, in Greety
Stones, and in Rocks.

You may observe more of them in Walls exposed to the _South_, than in
others; and that the Worms, that eat the Stone, live longer, then those,
{323} that eat the Mortar, which keep not above eight days alive. I have
observed all their parts with a very good _Microscope_, without which, and
a great deal of attention, 'tis difficult to see them well.

I have seen other very old Walls altogether eaten, as those of the _Temple_
at _Paris_, where I could find no Worms, but the Cavities were full of
Shells of various kinds, diversly figur'd and turn'd: all which I believe
to be little Animals petrified.

* * * * *

_Some pro