_The manner of preparing the Liquor, out of which =Salt-petre=
may be made by Boiling._
First of all, pour your second weaker Lixivium into your Copper, and
set it a boiling, then let your second stronger Lixivium run thereinto
by little and little; and then lastly, the first Lixivium it self, and
which is the chiefest of all, until the Copper be almost filled, and
the Lixivium be boil’d enough to shoot.
And now when you perceive that your Liquor is made strong enough by
boiling, put in a Brass Ladle perforated (or full of holes) several
times, even to the bottom of the Copper, and if the Lixivium lets fall
out of it any Salt, you will find it at the bottom, the which you may
take up with your Ladle.
Note also, That the Scum which at the end of this Boiling is
plentifully gathered, must be carefully taken away: Now then try the
readiness of your Lixiviums Crystallization, on this wise: Put either
two or three drops on a cold Iron, or on a Polish’d Plate of Iron, and
if it stands, or grows hard; that is, if when you turn the Iron up and
down, it does not run (or flow) down, these are signs of the fitness
of your Liquors Crystallization. Or else, you may put some of the
Lixivium in a Brass Vessel, and set it in cold water, and so you shall
see whether the Liquor be fitted enough to Crystallize; for assoon as
ever the Lixivium shall be cold, there will be plenty of Salt-petre
generated: Nay, even the very Brass Spoon it self denotes the goodness
of the Liquor, it being put into the Liquor, and again taken out, it
will show it sticking on it, as if it were Oil.
Out of a Centenary, or hundred weight of Liquor thus perfectly
prepared, there will proceed more than seventy pound of Salt-petre.
_The way of rightly using the Liquor for the Generating of a more
Crude_ Salt-petre.
Pour your Liquor prepared after the afore-shown manner, out of the
Copper into a narrow Tub, or Vessel, made of Firr, or Pine-tree wood;
wherein let it remain quiet, till it be a little refrigerated, and the
muddiness, or slimyness [_Limus_] appear, and you find that the salt
sticks on in Granes to the sides of the Vessel; now when you perceive
your Lixivium so cooled, as that you can put your finger thereinto
without burning, pull out the Plug, wherewith an hole made in this long
Vessel, about a span’s heighth from the bottom, was shut, or stopt,
and so let the Liquor run forth, into very great Wooden Vessels, and
deep, purposely made for such a business; or else into Copper Pans,
buried almost (up to their Necks) in the earth, (for the cooler the
place is, which they stand in, so much the better, and the more plenty
of Salt-petre is gathered, and Crystallizeth) and you will find that
your crude Salt-petre will shoot therein, the thickness of almost two
fingers breadth, partly of a whitish colour, partly yellow, and partly
blackish.
After that this boil’d Liquor hath stood for two days, and so many
nights in the Vessel, the Lixivium of the Salt-petre which swims at
top, must be taken away, which you may mix with the strong Lixivium,
and pour a second time upon Ashes, for else the Lixivium will contract
too much fatness, and there will be no Salt generated.
Sometimes it happens, that when the Ashes are not good, there’s no salt
at all gathered in the Liquor, in which case there is no presenter
Remedy, than to mix such a Lixivium stronger than is fit, with another,
and so pour it again upon new, and good Ashes, and then let the boiling
be again perfected after the afore-prescribed manner.
Likewise, when in the boiling you find the Lixivium very muddy, whereby
the Collection of the Salt is oft-times hindred, it must be taken away,
and let the Washer-Women, or Lawndresses have it, and other must be
substituted in its room, and be farther purified by the help of Ashes.
* * * * *
The Figure signed (_Numb. 2._) shews the manner of preparing the
Liquor by boiling, and of extracting and gathering the Salt
thereout of.
A _Long narrow Tubs, or Vessels, in which the decocted Liquor of the
Lixivium is cooled._