Pigeon-houses, Cellars, Barns, Ware-houses, or indeed any place which is covered from the Rain, which would dissolve it, and (as I have said) make it vegetate; as also from the Sun, which doth rarify it, and causeth it to be exhaled into the Air; (For the same reason Husbandmen also might make double or treble the profit they usually do of their Muck, if they will lay it up under a Hovel, or some covered place, until they carry it out upon their Land.) And I have been told by an experienced Workman, that no Earth yields Peter so plentifully, as that in Churches, were it not an impiety to disturb the Allies of our Ancestors, in that sacred Depository.
'Provided always, that the Earth be of good Mould, and the better the Mould is, the more Peter is produc'd; for in Clay, or sandy Earth, little or none is to be found: The freer ingress the Air hath into a place, is still of more advantage, so that the Sun be excluded: And let the Earth be never so good, if it be laid on a brick or boarded floor, it will not be so rich in Peter, as if it have free communication with the Exhalations of the lower parts of the Earth.
'In any place thus qualified, you cannot miss of good quantities of Peter, if it have not been drawn out in some Years before; which a Workman will quickly find, after he hath digged the first spadeful of Earth, by laying a little of it on the end of his tongue, and if it taste bitter, he is sure of good store of mineral, (as they love to call it) that is, Salt-peter; if the Ground be good, it continues rich to six or eight foot deep, and sometimes, but not often, to ten.
