narily four hours in melting. This
done, the Ashes are drawn out by a crooked Iron, and being put into an Iron
Wheel barrow, are carried out of the Hutt, and {46} being laid in a heap,
are covered with other exiled or drained Ashes, the better to keep them
warm; which is reiterated, as long as they make _Brimstone_.

To make _Coperas_ or _Vitriol_, they take a quantity of the said Ashes, and
throwing them into a square planked pit in the Earth, some four foot deep,
and eight foot square, they cover the same with ordinary water, and let it
lye twenty four hours, or until an Egg will swim upon the liquor, which is
a sign, that it is strong enough. When they will boyl this, they let it run
through Pipes into the Kettles, adding to it half as much Mother-water,
which is that water, that remains after boyling of the hardned _Coperas_.
The Kettles are made of Lead, 41/2 foot high, 6 foot long, and 3 foot broad,
standing upon thick Iron Barrs or Grates. In these the Liquor is boyled
with a strong Coal-fire, twenty four hours or more, according to the
strength or weakness of the Lee or Water. When it is come to a just
consistence, the fire is taken away, and the boyled liquor suffered to cool
somewhat, and then it is tapp'd out of the said Kettles, through holes
beneath in the sides of them, and conveyed through wooden Conduits into
several Receptacles, three foot deep and four foot long (made and ranged
not unlike our Tan-pits) where it remains fourteen or fifteen dayes, or so
long till the _Coperas_ separate it self from the water, and becomes icy
and hard. The remaining water is the above-mentioned Mother-water; and the
elixed or drained Ashes are the Dregs, or _Caput mortuum_, which the Lee,
whereof the _Vitriol_ is made, leaves behind it in the planked Pits.

* * * * *

_A further Account of Mr. _Boyle_'s Experimental _History_ of _Cold_._

In the first Papers of these _Philosophical Transactions_, some promise was
made of a _fuller_ account, to be given by the next, of the _Experimental
History of Cold_, composed by the Honourable Mr. _Robert Boyle_; it being
then supposed, that this _History_ would have been altogether printed off
at the time of publishing the {47} _Second_ Papers of these _Transactions_;
but the Press, employed upon this Treatise, having been retarded somewhat
longer than was ghessed, the said promise could not be performed before
this time: wherein it now concerns the in