Dictionarium polygraphicum. Chalcedony, Calcedony.

Dictionarium Polygraphicum:
Or, The Whole Body of Arts Regularly Digested.
Vol I.
London: Printed for C. Hitch and C. Davis in Pater-noster Row, and S. Austen in St. Paul's Church Yard. MDCCXXXV.
1735
Chalcedony, Calcedony is a precious stone of a bluish or yellowish colour, rank'd among the kinds of agate. It is suppos'd, by some, to be the white agate of the ancients, though there are sometimes found pieces of it blackish.

This stone is very fit for engraving, and much us'd, either to engrave arms, &c. upon, as being harder and preferable to crystal, if good, or to paint them on the backside. In some places, vases, cups, &c. are made of it. That which is clearest with a pale cast of blue is accounted the best.


To make a CHALCEDONY in glass.
There are three different ways to prepare an artificial Chalcedony, which will make three different species of it, all of them very fair, but whose beauty also may be augmented by the number of ingredients, they are compos'd of; and which cause those diversities of colours, which that stone ought to have.
Among the rest of the ingredients employ'd for this purpose, there are some that give no colour to glass, as tartar, soot, armoniac and mercury.
Those that are of an uncommon nature, as lead, soot, tartar, the azure stone, often hinder the union of the ingredients, by reason of the separation which may happen by the cooling the metal; which does not happen to those who know how to ob serve the degree of heat, wherein the principal knowledge of this art consists.


To make the first sort of CHALCEDONY.

Put a pound of aqua fortis prepar'd into a glass body with a long stick, and two ounces of silver in small and thin plates, or granulated, put the body in an ash furnace over a soft fire or in warm water, and the silver will be presently dissolv'd.

At the same time, take another body and dissolve in it three ounces of quicksilver; in twelve ounces of the same aqua fortis; then mix both the solutions together into a larger body, which set into the same bath of warm water, or ash furnace; then add to it three ounces of sal armoniac, which dissolve over a gentle fire, then add to it half an ounce of zaffer, and a quarter of an ounce of manganese prepar’d by little and little, with as much Feretto of Spain, also by little and little; for fear the matter coming to swell too much, should break the vessel.

Add to all these ingredients half an ounce of crocus martis calcin'd with sulphur, as much scales of copper three times calcin'd, which ought to boil like manganese; as much blue lake (such as is us’d by painters) and the same quantity of red lead, the whole reduc’d to powder.

In putting in these powders, you must gently stir the glass body, that they may the better incorporate with the aqua fortis, but be sure to take care that there be not too much heat; then stop the mattrass (or glass body) very well, stirring it well every day for ten days, that the powders may well incorporate, and that they may always appear as separated from the water.

Set the large glass body into a sand furnace, in a temperate heat, or rather empty it into a glass cucurbit, after you have well luted it at the bottom, and set it over the same fire, so that the aqua fortis may evaporate in twenty four hours; and at the bottom of the vessel you will have a yellow powder, which keep safely in glasses for use.

When you are to make the Chalcedony, take white crystal in glass, well purified, and that has been often melted; for crystal new made, is not fit for that operation, because the colours will not stick to it, but are consum’d by the frit.

Put about ten pounds of this crystalline glass into a pot, and when it is well melted, put in about an ounce and a half of your yellow powder at three different times, mix the glass well with it each time, that the powder may incorporate with it, the glass being thus well mixt; let it stand an hour, then mix it once more, and let it stand for twenty four hours; then mix it again for the last time, and make an eslay of it, it will give a yellowish azure colour.

Having made your essay, and found your matter right, the pot may be taken out of the furnace, and when it is cold, you'll have the colours which shall represent the wavings of the sea, and other fine things.

But to have a very fair Chalcedony, you must perform a second operation, to join to the first, by taking four ounces of tartar calcin'd, one ounce of chimney soot well purified, one quarter of an ounce of crocus martis calcin'd with sulphur, mix the whole together, then put it into the melted metal at five or six different times; otherwise the impetuous swelling of the metals would break the pot, and the whole would be lost; which may be avoided by putting it in by little and little, stirring it each time well, that the matters may incorporate; also make the pot boil, and let it stand twenty four hours. After which time you may work it into what you please.

Which set into the furnace to whiten, and see if the glass please you, if it be green without, and blue, white, red, yellow, and of all other colours, like jasper and oriental agate.

If looking on it obliquely, it be red like fire, and held to the fun, it shews the colours of the rain-bow by reflection of the rays; if so, then it is fit to make all sorts of vessels, which may be polish’d at the wheel.

If it be pale and clear, more calcin'd tartar and soot must be added to it, as before, stirring it well to make it incorporate; then let the glass stand and purify several hours, and then you may work it, as you please.

Chalcedony is much us’d for the effigies of Kings and Princes, for heads, cups, and many other vessels; principally for seals, because it is easily engraven, and the wax will not stick to it.


A second species of CHALCEDONY finer than the former.

1. Put a pound of aqua fortis, and three ounces of coppel'd silver, granulated into a glass body, in order that it may be the better dissolv’d.

2. Put also a pound of aqua fortis, and five ounces of mercury well purified, and pass'd through a glove into another glass body, and close it well.

3. Put also a pound of aqua fortis with two ounces of sal armoniac, into another glass vessel to be dissolv’d.
When it is dissolv’d, add to it crocus martis, prepar’d feretto of Spain, leaves of copper calcin'd, by means of sulphur, of each half an ounce; reduce the whole into powder, putting them in one after the other, and by little and little, for fear the matter should break the vessel.

4. Put one pound of aqua fortis, with two ounces of sal armoniack into another earthen body, and when the whole is dissolv’d, add successively as before of good crude antimony, of blue enamel, such as is us’d by painters, of red lead, and of vitriol well purified, each half an ounce, all of them well pulveriz'd; these also must be put in by little and little as before, for fear of breaking the vessel, then close it well.

5. Put also one pound of aqua fortis, and two ounces of sal armoniack into another glass body, and when dissolv’d, add two ounces of zaffer prepar'd, a quarter of an ounce of manganese of Piedmont, also prepar’d, half an ounce of thrice calcin’d copper and an ounce of cinnabar; reduce all to a fine powder, and put them in by little and little into the vessel, taking care that the powders don't by too much swelling break the vessel, then close it well.

6. Put a pound of aqua fortis, and two ounces of sal armoniac, into a fixth vessel of the same bigness as the rest, and as foon as it is dissolv'd, cast in two ounces of cerus by little and little, for that will also cause a fermentation. Then add the like weight of painter's red lake, and as much of iron scales from the anvil, putting it in by little and little, for the reasons before men tioned; and in a word proceed very slowly in all these operations, flopping all the vessels well.

Set all these vessels on a gentle fire of ashes, or in a warm bath, to hasten the solution of the materials, they must be stirr'd at least fix times a day, for twelve days, in which they must continue in that heat, that the aqua fortis may the better penetrate the powders, and they communicate their tinctures the better to the glass. The twelve days being ended, put the whole into a large glass crucible, and lute it well for fear of breaking, pouring them gently in out of the fix matrasses one after the other, having first well stirr'd each of them; then set this cucurbit on a gentle ash fire, and having fitted a head and receiver to it, and luted the joints well, then gently distil all the aqua fortis that is in the body, for the space of twenty four hours, making a very gentle fire towards the end, otherwise the powders may be spoil'd by too much heat, and the spirits which ought to remain in the powder, would pass into the receiver.

Then they will remain at the bottom of the vessel of a yellowish red colour, which keep in a glass well stopp'd for tinging glass or crystal, which is yet better.


The third and last way of making a CHALCEDONY.
This though something more tedious surpasses the two other in beauty.

1. To make this preparation: Take the aqua fortis, of which put one pound into a glass matrass, with four ounces of leaf silver to dissolve, then stop the matrass.

2. Put a pound of the same aqua fortis, with five ounces of mercury purified with salt and vinegar, after the following manner.
Put common salt into a wooden dish, sprinkle it with vinegar, and add to it a little common fair water to make it dissolve, put in the mercury, and stir it well with a wooden pestle to draw out the blackness, repeat the washing them often with salt and vinegar, till there be no more blackness; then dry them with warm linen or cotton, and pass it through a glove; then it will be purified and fit to put into the aqua fortis. When it is dissolv’d, stop the matrass and keep it.

3. Take another glass body, put into it another pound of aqua fortis, with three ounces of fine silver calcin'd.

Amalgamate the silver with the mercury, as the gold smiths usually do (See AMALGAMATION) and put it into a crucible, with its weight of common salt purified.
Then set the crucible on hot coals, that the mercury may evaporate, and that only the silver may remain at the bottom, which will be purified and calcin'd.
Then add to that calcin’d silver, an equal weight of common salt purified as before, mix them well together, and set them over the fire in a crucible to calcine them again; then wash them well with warm water to take out the salt, and afterwards put this silver into a glass vial filled with common water, boil it, till one fourth of it is consum’d, then let it cool and settle to the bottom, after that decant off the water, and put more upon it.
Repeat this process with fresh water three times, and at the fourth dry the silver, and put it into the aqua fortis, and stir it well and stop the matrass.

The method of purifying common SALT, is as follows:
Dissolve fea-salt in a convenient quantity of common water, boiling it for the space of two hours; then let the water rest, that the earthy part of the salt may settle to the bottom; then filter the water and evaporate it in an earthen vessel, or rather in a glass cucurbit, till the salt remain dry at the bottom.
Dissolve this salt again, making the water boil, then let it stand for the dregs to settle, after which filter it and evaporate it as before; which you must continue to do, till there are no more fæces or dregs, and it will be well purified and prepar’d.

In order to continue the preparation of the materials.

4. Put a pound of aqua fortis into a glass matrass, and add three ounces of purified sal armoniac; that is to say filtred and whitened, till it leave no fæces or dregs, as has been shewn in common salt; then dissolve a quarter of an ounce of silver in that water, and stop the vessel well.

5. Put also another pound of aqua fortis into another glass matrass, with three ounces of purified sal armoniac, that is to fay, filter'd and whitened till it leave no faces or dregs, as has been shewn as to common salt; then diffolve a quarter of an ounce of silver in that water, and stop the vessel well.

6. Put also another pound of aqua fortis into another glass matrass, with two ounces of sal armoniac when it is dissolv’d, put into that water cinnabar and crocus martis calcin'd with sulphur as above; of ultramarine and feretto of Spain prepar’d, of each half an ounce, having reduc’d all to a fine powder; this must be put in by little and little, for fear of breaking the vessel by the fermentation; which they make with the aqua fortis, then stop the matrass.

7. Put a pound of aqua fortis into another matrass, and dissolve in it two ounces of sal armoniac as before; add to it of crocus martis calcin'd with calcin'd tin, known among the glass men, of zaffer described and cinnabar each half an ounce, powdering them all very well, putting them in by little and little, as before, then stop the matrass.

8. Put also another pound of aqua fortis into another matrass, and dissolve in it two ounces of sal armoniac; then add an ounce of small leaves of copper calcin'd, half an ounce of scales of copper thrice calcin'd, half an ounce of manganese of Piedmont prepar'd, and half an ounce of scales of iron, which fall from the smith's anvil, the whole being reduced to a fine powder; which throw in by little and little as before, then stop it well.

9. Put another pound of aqua fortis into another glass body, and add to it two ounces of sal armoniac, the dissolution being made, put to it half an ounce of red lead by little and little, and one ounce of scales of copper, half an ounce of crude antimony, and as much caput mortuum of vitriol purified, all being reduc’d to a fine powder; then stop the matrass.

10. Put another pound of aqua fortis into another glass matrass, with two ounces of sal armoniac, add to this water orpiment, white arsenic and painters lake of each half an ounce; let the whole be finely powder'd, put them into a matrass by little and little as before, and stop it up well.

It has not been repeated at each operation, that you must set your matrass on an ash furnace over a gentle heat, or in a warm bath to hasten the solution of the materials; because it has been said, that it must be always done in the preparation of these things, which are for tinging the first species of Chalcedony.

All the nine matrasses mentioned in this process, must remain fifteen days in the same heat, and be often stirr'd daily, that the water may the better operate on the materials, subtilizing them, and well opening their tinctures.

Then put all these materials with the aqua fortis into a large glass body, by little and little, that they may unite well together; close the body, and set it on the same heat, stirring it well for fix days.

After this, take a large glass cucurbit well luted half way up the body of it, and set it on an ash furnace, put into it all the materials out of the body; fit a head and receiver to it, lute the joints well, and distil it for twenty four hours over a gentle fire, left the colours should be spoil'd, that the water may pass gently over, and the spirits remain in the powder, which of green will become yellow.

Thus putting that powder in the requisite dose (as has been taught in the first species of Chalcedony) into purified metal made of broken pieces of crystal, and not of frit; and adding to it in its due time calcin'd tartar, chimney soot, crocus martis made with vinegar, as has been directed, and these materials will give an opacity to glass, which in twenty four hours time may be wrought, managing it well with proper tools and often beating it, and you will have things of an extraordinary beauty, greater than can be imagin'd.