Dictionarium polygraphicum. Ultramarine.

Dictionarium Polygraphicum:
Or, The Whole Body of Arts Regularly Digested.
Vol II.
London: Printed for C. Hitch and C. Davis in Pater-noster Row, and S. Austen in St. Paul's Church Yard. MDCCXXXV.
1735
ULTRAMARINE is a rich and beautiful blue used by Painters from an azure stone commonly call'd Lapis Lazuli, which is an opaque stone of a fine sky-colour or Turkish blue; or like the blue flowers that grow in corn-fields; it is embelhsh'd with small streaks and sparkles of a gold colour.

This stone comes from Persia and the East-Indies, and as some say from Africa; but if from the last, it is in no great quantities.

There is also a kind of lapis lazuli found in Germany and Hungary; but not fix'd, tho' as hard as that from Asia, which they call Lesurstein and its colour Asurbleau; but its colour changes in sometime, and becomes greenish: however it is used by Painites.

The best Lapis Lazuli is that which is fix'd; that is, can endure the fire without altering colour.

Before you proceed to extract your ultramarine, take some account of the manner, to know whether the stone be good, for unless it is singularly so, you'll lose your labour: put pieces thereof on live coals, and blow them continually for an hour; if they retain their first hardness and colour afterwards, you may conclude them good; but if they crumble between your fingers, they are naught. It may be tried otherwise in an iron-ladle put into a furnace with some of the stone to heat, and so quench it in strong vinegar; if the colour remains still unchang'd and splendid, you may assure your self 'tis good.

When you have made this tryal, calcine it, which to do the easier, break the stone to pieces, as small as hazle-nuts, wash them afterwards in warm water, and set them in a crucible, on a windfurnace, or into an iron-ladle to reunite; then cast them into a glaz'd earthen vessel of distill'd vinegar to quench them in; do thus seven times, to prepare them by calcination for powdering, and to prevent their sticking to the mortar.

Thus calcin'd, dry them well, and so powder them in a stone-mortar well cover'd, and accordingly scarce it with the same caution, as perfumers do their most delicate and finest powders, lest the best should go off, and dispel it self in the air: and thus preserve this precious powder with all imaginable care.

Some derive its name Ultramarine of the Latin ultra beyond and marinus of or belonging to the sea; a.d. beyond-sea, because first brought into Europe from India and Persia.

It is the common opinion, that the method of making it was first discover'd in England by a member of the East-India company; who having a quarrel with his associates, made the secret publick to be reveng'd of them.



To make a liquid for moistning and grinding tht powder withal, &c.

For moistning and grinding your aforesaid powder of the stone, take a pound and a half of running warer, and put this into a new earthen pot, add to it an egg-shell full of raw honey, boil it until it have no more scum; take the pot off, and keep this hydromel, or liquid for use in bottles, as we shall give occasion sbr hereafter.

This done, take four scruples of the best gum dragon, grind it on your marble, with some of the hydromel, and then put it into a glass; add thereto as much hydromel as you find con venient to bring it to a violet-colour, so cover it, and preserve it for use. This liquid is good for your powder of lapis lazuli; if the colour be too violet, add the less hereof; if otherwise, the more, as your judgment, or experience shall direct.

Put half a pound df powder at a time into a small porphyry, or marble vessel, the larger the mortar the worse, for you'll lose more, and be longer a grinding; pour leisurely by little and little thereon, some of your violet liquid, grind these together for a full Hour, still wetting it; you may use three or four ounces of liquid to the half pound of powder, and you'll have it very good; you must take care of grinding it tdo long, for then it will lose its colour.

When 'tis thus ground, dry it on a marble or flat stone, where the sun does not come at all, cover it well to preserve it from dust; when 'tis dry, 'twill powder easily between your fingers, if it be rightly done; if so, let it alone on the marble, but if it be clammy, or stick, take it off, for it has still some unctuosity of the honey in it, which must be cleansed away by a cement.

Your lapis being thus dry, wash it well before you put it to the cement, for which you must use a glaz'd earthen bason round above like a barber's, and well glaz'd within; put your lapis therein, and pour thereon some of the mild lixivium hereafter mention'd, as much as will rise above the surface four inches; wash the lapis very well with your hands, and then let it settle, and 'twill precipitate. The liquid being clear'd again, decant it into a large copper, or earthen vessel, then let the lapis dry in a shade in the same vessel it was wash'd in, and spread it afterwards on the flat marble, or porphyry, and there let it lie until quite dry: thus it is prepard for mixing with the cement, of which we will give the preparation hereafter .



To prepare a mild and a strong Lixivium for the Lapis Lazuli.

To make these lixiviums, take ten handfuls of vine-stalk ashes well scare'd; put this into a large vessel that will hold thirty pound of water, with a faucet at bottom; press the ashes very well, and put to them twenty pound of warm water. When it is funk to the bottom, open the faucet, so as it may only drop into an earthen vessel; when it is all come out, stop the hole, and strain this lixivium through a felt strainer, and so keep it in a glass, or glaz'd pot well cover'd: this is the strong lixivium.

Again, pour in on the sime ashes, the like quantity of warm water, and do as before; so you'll have an indifferent strong lixivium, which keep as the former.

Do this a third time, and you'll have the mild lixivium mention'd in the preceding page.

These three are very useful both for moistning, and to draw the powder of lapis lazuli from the cement; wherewith it must be mix'd, as will be shewn anon: which separation being sometimes hard to perform, we are oblig'd to have recourse to these varieties of lixivium: stronger, or weaker, as we find them convenient for the purpose.

You may yet make another lixivium to take away the greasiness of the cement thus; boil calx of tartar, as much as you please, in clean water, for about a quarter of an hour, and keep u for use as the former. This is excellent for washing the lapis lazuli with; it strengthens and improves the colour thereof.



The form of the glasses for preserving the liquids in, which are employ'd on the Lapis Lazuli.

There always remains some of your colour in the waters, or lixivium, wherein the lapis lazuli is prepar'd throughout all the process; you must therefore have a very large vessel of brass, or earthen ware, glaz'd and polish'd very well at bottom, wherein must be three holes; one in the middle of the side, the next a little lower, and the last about two inches from the bottom; stop these holes without side very close, to prevent leakage.

Then pour all your waters into this; though you then perceive no colour ar all, yet after ten days you'll have it at bottom, whither it will descend gently; and to get it you must go artificially to work, first opening the first cock or hole, andletout the water above that, before you open the other two; and thus yon may get the colour without muddying, or lofing any by the waters, which mix with the rest.


To make strong cement to mix with Lapis Lazuli, to separate the finer and better stuff from the other.

One cannot so easily part the finer lapis lazuli from its grosser pans, without making use of this cement to unbind the parts: take four ounces of very pure and clear Venice-turpentine; six ounces of rosin of the pine, six ounces of Grecian pitch, three' ounces of very good mastich, three ounces of fresh wax, an ounce and half or linseed-oil cleansed, as ill all be directed.

Put the turpentine into a new-glaz'd earthen pot very clean, to dissolve over a flow charcoal fire, and continue stirring it with a wooden spatula, throw into this by degrees, the rosin of the pine, in small pieces, and stir it still very well; thus put in successively the pitch, the mastick in powder, and last of all the wax sliced small, stirring all continually about to mix and incorporate. Take great care of your fire, lest the cement should blaze, or burn, all the ingredients being hot of themselves, and combustible. Having well incorporated them, pour in the linseed-oil, stirring it as before, and so let it boil gently for a quarter of an hour.

To try whether the cement be enough, drop some of it osf the spatula into a vessel of cold water: if it spread, 'tis not enough; but if it do not, 'tis sufficiently boil'd; so take it off. Or else you may wet your fingers, and take a drop thereof, roll and draw it out in length; if it snaps and breaks of it self, 'tis a sign that 'tis enough: take it off, and pour it boiling hot into an hypocras-bag steeped before in hot water; take care to let it go all through into a vessel of cold water, and for the better se curity, squeeze it along from top to bottom with two flat sticks, that none may remain in your bag. Afterwards work it well with your hands, till all the water be drained from it, and because being hot it may stick to your fingers, you may anoint them with some of the linseed-oil.

The cement being thus prepared, keep it in a vessel of cold water, shifting your water every day, or every second day; and by this method you may keep itfor ten years.


To make a weaker Cement for separating the colours of Lapis Lazuli.

This second cement, which is the softer and milder, ought to be first employ'd on the powder of lapis lazuli; it draws the colour much quicker and better than the strong cement, which ought not to be used till after the milder; the whole se cret of separating the colours, consisting in ufing the cements; for without a due care hereof, it cannot be done perfectly.

To make this cement, you must take four ounces of very pure turpentine, four ounces of rosin of pine, six ounces of Grecian pitch, one ounce of fresh wax, six drams of linseed-oil, purified, mix and incorporate them successively as before. Ob serve only, that this is sooner done than the former, because 'tis weaker, and will give the colour soonest; therefore you must manage accordingly.



To purify Linseed-Oil.

The use we have for linseed-oil in our cement, obliges us to give this preparation, and way of purifying it, whereby it is made more fit for our purpose.

Take good and clear linseed oil, of the colour of saffron, and put it into a glass, shap'd like an ox-horn, with an hole at bottom to let out the water, which you must mix with the oil, letting them settle until the oil rises all uppermost; then open the hole, and let the water out, and the oil remain behind. Then shake the oil again, with more fresh water, let it settle, and the water run out as before; do thus eight or ten times, till the water comes out as clear as it went in, and so the oil will be pure and fit for your use; keep it well stopt in a glass bottle. If you can't get linseed-oil, you may use oil of bitter-almonds, without purifying, for it needs none; but take notice, the linseed oil is belt or any, though cheaper than the other.



How to incorporate the powder of Lapis Lazuli with the strong, or weaker cement.

We have already given the way to prepare the powder for mixing with the cement, to extract the colours; we now come to shew how to mix it with the cement, in order to extract the ultramarhe from them for painting.

Take a pound of the powder, and the like quantity of cement assign'd before, observing always to take the first that was work'd with the hands; cut the cement small, and the pieces being a little wet, put them into a glaz'd earthen pot, over a fire of red-hot ashes, to melt, and take care it does not boil; if it should, you must prevent the damage which it might cause, by putting in some linseed-oil. The cement being thus melted, anoint all your spatula over, from the handle downwards with the same oil, and so put in the powder by very little quantities, and taking a great deal of time, that they may the better incorporate; and be sure to stir it all the while very well with the spatula, so as to make it all alike, until it become like an ointment or salve: then off with the pot, and throw the stuff boiling hot into an earthen-bason of cold water, and at that very instant take off all that sticks to the sides of the pot. When it is cold enough to be handled, if it appears well colour'd, it is a sign you have work'd it well: this done, rub your hand with linseed-oil, and work it as they do a paste of bread or dough, for one hour, that it may be throughly compact. The longer you work it, the better and easier the colour may be drawn; afterwards make it up like a loaf or brick, and set it in an earthen dish to dry, pouring thereon some fresh water; let it steep for fifteen days, the longer the bettef for extracting the ultramarine.



To extract the Ultramarine.

Take therefore the loaf of cement and powder, washing it in the same water extraordinary well with your hands; weigh it to know the quantity of oil it requires, and put it into an earthen bowl or dim, very smoothly glaz'd, rubbing first the bottom with your linseed oil; then pour in water scarce warm'd, until it arise two inches above the matter; let it stand in this condition a full quarter of an hour (or less in the spring-time;) pour this water afterwards into the vessel before mention'd, adding more warm water to your matter, and so it will soften: continue thus whilst there remains any tincture thereon; by this means all the substance that is good for any thing, will be se parated from the cement, which cannot be done otherwise.

Whilst it is imbib'd in the warm water, you must move and rowl it gently round with two sticks, or spatula's of box, or any other well polish'd wood, rounded ac the ends smooth like a wallnut; let them be about an ell long, and an inch thick. When ever you perceive the matter stict to the bottom of your disj, rub your hands with linseed-oil, and stir it about leisurely so as to colour the water, which you must put along with the former, in the mean time holding up the matter with your staves, lest it should stick to the vessel.

Take notice that a little steeping at first will tinge the water very much, and when the cement is just yielding its colour, it will discover certain bluish streaks on the water like the sun's-rays, and then you must strain this water out among the other, through a scarce, that the grosser part of the cement may remain; afterwards pour in by little and little the fresh warm water, stirring the cement easily, that it may not dilate too much, and give its colour all at once. After you have thus stirr'd it about five or six times, close and amass it anew, by which means you'll see how much it is diminish'd, and what quantity of colour it has given.

If the lapis be good and right, you'll find the first steepings, yield about four or five ounces of ultramarine, which keep apart by its self as the best and finest colour, though it appear grosser than the others of this sort, by reason of the gold-colour'd veins, which are peculiarly therein.

For the second, whereof you'll have three or four ounces, you must follow the processes aforementioned: this indeed will be finer than the other, but not so good a colour; keep it also by itself.

Draw off a third, and this will b e still finer than the former, but paler, and more bright coloured. You must still pursue the same Directions to extract it, letting your Water be but half lukewarm, and take care to manage the cement dextroufly with the spatula's, and so preserve the colour apart.

You may extract a fourth colour after th'u rate, but the wa fer must be hotter, and you must press the cement very well with the spatula's to squeete out the colour; and if meer water will not do, make use of the mild lixivium. This last colour will be greyish orash-colour'd, and of no great value, and therefore not at all to be mix'd with any of the rest.

Observe here that you can't take up less than eight hours full, to extract the colours, nor less than ten or twelve to allow the water for settling; and if you perceive the colour does not come out free enough with the warm water, add a third part of our mild lixivium, and if that does not do, use all lixivium, but let it be cold; and when that fails too of effecting it sufficiently, you must make a lixivium of vine.stalk ashes, and this being strain'd, let it boil for half a quarter of an hour, until it be sharp enough to bite your tongue; and then let it settle and grow clear; this is your last shift for extracting your colour, and with this heated, walli your cement very well, and set it aside. The whole design of all this trouble, is only to serve for obtaining the greater quantity of ultramarine, and this consists in the goodness of the lapis lazuli and the cement, which the circumspection and care taken in all their preparations must advance.



The method of cleansing the Ultramarine when it it separated from the cement.

After you have extracted all your colours out of the cement, »nd the water quite settled and separated from them, pour on some of the mild lixivium before prescribed, and so wash them with your hands, (but don't rub it between them) thus you'll fake away all the grease of the cement; afterwards wash it three or four times in fair water, and ler me waters settle well before you put them into their proper vessels.

You may else another way purge the ultramarine thus: take the yolks of pullers-eggs, that have been sed only with corn, and not with greens; prick these with a pin, and so moisten the colours, kneading the mass with yqur hands, and washing it afterwards with your mild lixivium, until the lixivium falls oft clear again. This done, wash them three or four times over with fair water, letting the waters settle well before you put them into their vessels.

This last way of purifying the ultramarine, is mighty effectual; but here is another help to be used with it, which is a very great secret, and performed thus: After the Colours are quite washed according to former directions, as well as possible, you must cast therein by little and little, a bull's-gall, rubbing it by degrees with your hands; so wash them often in dear water, and you'll have the colour in full perfection.



To strain off' the Ultramarine already wash'd and purified.

It is necessary to strain off the ultramarine, and the rest of the colours, that if any grease, or unctuosity of the cement remain, it may be taken quite away, for these colours require a perfect and extraordinary purification.

For this purpose take a fine searce, and pour thereon the last waters, with which you washed the ultramarine, and so strain them afterwards through another fine searce, and a third time through red quintain or crape; but you must observe when you strain them, to let them stand 'till you perceive them limpid and clear, and so soak off the water dextrously with a spunge, and be sure not to strain them promiscuously all together.

This being done to all the waters, let your colours settle in their proper vessels, and dry in the shade; when dry, put them into little leather bags; tie these close, rubbing them and pres? sing them with your hands: this will make them very subtile, and when the bags are opened, they'll shew much fairer than before.



To correct the colour just before prepared.

Few persons, unless such as are very curious of their work, make any use hereof, because of the time it takes up, tho' it would turn very much to their account; for one ounce of this colour corrected, will go farther than three that are not.

If you would make your colours just before prepared, much finer and effectual than they are, mix them again with a strong cement, and let them remain therein for three days; afterwards proceed according to the last directions, to separate them again; reiterate this over again, and you'll have them exceeding good; and tho' they diminish somewhat in weight, yet that loss will be repaid considerably in the beauty and value.




Another way to make Ultramarine, and draw off the colours with more expedition.

This method of making ultramarine is much more ready than the former; and experience will shew whether the colour be a gainer or loser thereby.

Take a pound of lapis lazuli, calcine it in a crucible, and quench it afterwards in vinegar, so let it dry, and then reduce it to a very fine powder; grind it on a porphyry with fair water, and set in a glazed earthen vessel in the shade, until it be dry; if you find it coagulated all in a mass, you must powder it again.

This done, make a cement of three ounces of Grecian pitch, four ounces of rosin of the pine, three ounces of mastich, three ounces of frankincense, two ounces of oil-olive; set these over a slow fire in a small earthen pot, into which pour first the oil, and when that's hot, put in the rosin, then the pitch, then the incense, and last of all the mastich, stirring them continually with the wooden spatula, and let them boil a little.

Having made the cement, get another earthen vessel, and put thereinto the lapis lazuli, and pour on it the cement hot, stirring the whole together with the spatula very leisurely, until they perfectly incorporate; let this stand a whole day, and when you would draw off the colours, pour thereon boiling water, stirring it very smartly.

When it begins to cool, pour it out, and so put in more hot water; do thus 'till the warer begins to draw off the colour, and so continue until it be quite extracted; you may distinguish the waters, and so set them apart, and obtain the variety of colour as in the former way.

If your colour seems to be clammy or nasty, you may cor rect it thus: aid thereto tartar dissolved in water, as much as will drown it, and let it repose for one day at least, so wash it in warm water, and you will by that means have it very correct, and well-purified.



Another way to make Ultramarine.

Granting the two former ways to be sufficient, we will how ever here give a third, which we believe may as well be pleafing to those, who are not satssfied with the other, as to such per sons as have a curiosity for these sorts of work; and thus we pro pose to procee'd.

You must break the lapis into gross pieces, as small as nuts, then set these in a crucible into the furnace, till they redden with heat, and so cast them into cold water; do thus six or seven times, and so reduce them to impalpable powder in a porphyrymortar well covered over, lest the powder, which is very subtile, should disperse away into the air, and then scarce it with a fine scarce also' covered.

After this, take rosin of pines, ordinary black pitch, mashch, fresh wax, and turpentine, of each three ounces; of incense and linseed-oil, each one ounce; melt all together in an earthen vessel, stirring them very well, 'that they may mix; this stuff being well incorporated, cast it into water, and keep it for use.

To each pound of lapis lazuli add ten ounces thereof, and set them to dissolve in a pot over a small fire, first melting the cement, and then casting on the lapis lazuli 'by little and little, observing such an order in this, and continually stirring the mass with a stick, that they may mix insensibly together. Afterwards cast the mass into an earthen vessel of cold water, and anointing your hands with linseed-oil, mould it up into a number of cakes, or rolls, which leave in cold water for five days, shifting the water every other day.

This done, put them into a large and very clean glazed earthen vessel, pouringon them some clean hot water; when that cools, pour in more hot, and do thus 'till the pastils soften with the heat of the water: this done, put them into hot water, and let them be until it receive a bluish colour. Strain this water to receive the grosser pieces, and so put it into another glazed earthen vessel very clean, adding more to the pastils, which strain through a fine searce afterwards among the former; continue this until all the colour be extracted, and no more remain behind.

Your water must be only warm, otherwise it will occasion a blackness in the colour, which is to be taken care of, and imports very much.

All the coloured waters being in the vessel, you may cleanse them of any unctuosity, by repofing them for twenty-four hours, in which time the colour will stick to the bottom; then you may pour off the water gently into another vessel, and it will carry oft the grease along with it; strain it afterwards into the veslel, where the colour is again, through a fine searce, and all the grease and nastiness will be left behind. Do thus thrice, stirring the colour very well every time you return the water to it, that the filth and grease may ascend from it, and it will always stay in straining on the searce behind the water.

This done, let the colour precipitate entirely, and so pour off all the water very leisurely, for rear of disturbing it; dry this colour, and you'll have delicate ultramarine.

If you would imitate this colour at little charge, make use of our blue enamel, after the same manner; and instead of the lapis lazuli, observing without exception the like regimen and prescription just now delivered in every respect, and by this means you'll have a very pretty agreeable colour to paint with, and for tinging of glass.

This blue is qne of the richest and most valuable colours used in painting.

Those, who prepare it, make usually four sorts, which procur'd by so many different lotions, or washings.

There is ultramarine of the first sort sold for 11 l. sterling an ounce, and of the last for about twelve or fifteen shillings.

Ultramarine must be chosen of an high colour, and well-ground, which may be known by putting it between the teeth, and if it seel gritty, it is a sign it has not been well-ground.

To know whether it be pure and unmix'd, put a little of it into a crucible, and so heat it red-hot; and if the powder has not chang'd its colour after this trial, it is certainly pure; on the contrary, if there be any change, or any black specks in it, then it has. been adulterated.

Besides this, there is another sort call'd common, or Dutch ultramarine, which is only lapis, or smalt well-ground and pulveriz'd; the colour of which, when used by the painters, is much like that of true ultramarine, tho' much less valued.



To make Ultramarine.

Pour five ounces ot linseed-oil into an earthen dish, with three or sour drops of water, set it on the fire, and let it stand 'till it begins to fry or boil; and then put in half a poundof white Virgin wax, broken into small bits. When the wax is melted, put in half a pound of Greek pitch, and two ounces of powder of mastich, which has been before melted by itself, and also an ounce of turpentine; let all together stand over the fire to melt for aa hour.

Afterwards pour this composition into cold water, and if it proves soft like butter, it is enough; but if you seel any hard grains or grit, conclude that the majlich has not been melted enough, therefore set it over the fire again.

When the whole is brought to a due temper; put blue lapis into a crucible, and set it into the fire 'till it is red-hot, like the tire itself, and then throw it into white-wine vinegar; which it will imbibe, or absorb, 'till it bursts and breaks into small bits. Pound these bits in a mortar, and then incorporate this powder with a little of the above-mentioned composition; but with as little, as possibly may be, and let it remain in this state for about fourteen or fifteen days.

This being done, lay a board a little inclin'd upon the edge of a table (which board, if it had a channel or trench cut along it, would be more convenient) and under the foot of this board place a glass vessel or receiver, and put the blue paste at the upper part of it, and a vessel of water over that, so that it may distil drop by drop upon the paste.

Having dispos'd all things in this manner, help the water to dilute the paste, by stirring it very gently with the small endof a smooth stick.

The first blue, which will come away drop by drop, will prove the finest; and when you perceive that it begins to lose part of its beauty, change the vessel that receives it, and this will be a second blue; and you may likewise by thus changing the receiver have a third sort, which you may use.

Set these three sorts of ultramarine to dry, then put them up separately in bags of white leather.




Another way of making Ultramarine.

Take a quarter of a pound of lapis lazuli, and lay it upon burning coals, letting it lie 'till it is red-hot, and then quench it in very strong vinegar.

After this has been done, grind upon a hard marble stone with rectified brandy; the more it is ground, the finer the ultramarine will be. When it has been thoroughly ground, leave it upon the marble, or you may put it up in a vessel, while you prepare a paste, or pastel, for the incorporating the lapis with.

In order to make this paste, take two ounces of yellow wax, two ounces of turpentine, as much rosin, and as much linseed-oil; melt all these together over a flow fire, 'till they begin to bubble, which when it does, it is enough.

Pour this melted composition into glax'd pans, and it will be your ultramarine pastel or paste, of which take a quantity proportionable to that of the lapis, that has been prepar'd, and knead them together upon the marble stone, i. e. both the lapis and pastel together, which when they have been incorporated, leave them in that state for a night.

Then in order to force the ultramarine out of the pastel, pour fair water upon it, and knead it with your hands like a piece of dough, and the ultramarine will squeeze out, which is to be receiv d into an earthen vessel set under your hands; then leave it to settle in the said water, 'till you perceive the ultramarine has funk to the bottom.


Another way.
Take linseed-oil, new wax, and arganson, of each two ounces; rosin, and mastich in tears, of each half an ounce; Burgundy pitch two ounces; incense of frankincense one drachm, of dragon's-blood the same quantity; let each of these ingredients be bruised in a mortar by themselves; then set the linseed-oil over the fire in a pan, and when it begins to fry, put in the ingredients one after another, letting the dragon's-blood be put in last; stirring the others continually with a stick, or spatula, anci when you perceive the composition to become glutinous and stringy to your fingers, the paste is fit for use.

Then having prepar'd the lapis lazuli, by burning it on a coalfire, quenching it in white-wine vinegar, grinding it very fine upon a marble, and searcing it through a fine searce; incorporate it with your paste, and let it remain in that state for twentyfour hours, and then force out the ultramarine with spring-water, but be sure not to use any other water, and you will have the first tincture, or degree of blue, which will be the finest and most lively'of all: repeat this to the third time, and if after all the remains be put into a chymical vessel, you may get out the gold with which the lapis was impregnated.

Some persons knead the paste at once in a vessel of milk-warm water, into which they squeeze the ultramarine, leaving it to settle for twenty-four hours or more, and then pour off the water by inclination, and find the ultramarine at the bottom, which they set to dry in the sun.

Some leave the lapis incorporated in the paste for the space of a month, before they squeeze out the ultramarine; and in the paste put only oil of turpentine, instead of linseed-oil and turpentine; and black pitch instead of Burgundy pitch: and as for the lapis itself, they heat it, quench it, grind it, and scarce kin the manner before directed.