Dictionarium polygraphicum. Crocus martis, Crocus ferri.

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
Crocus martis, Crocus ferri for colouring of glass. Of this there are several ways of preparing, some more simple, and others more extraordinary and curious, both with and without liquors or menstruums; the effects of which are different both in tinging of glass and other uses to which it is put.

CROCUS MARTIS, made without menstruums, depends on a very fine calcination of the iron, by means of which, the tincture that is extracted gives a very fine red to glass, and so communicates it self to it, that it not only manifests it self, but makes all other metalline colours (which ordinarily are hidden and dead in glass) appear fair and resplendent.

As to the way of menstruums, it may be said, that all acid and corrosive juices which operate on copper, will also do the same on iron; so that you will always have a red colour, more or less bright, and which may be mixt with tinctures of other metals to make other different colours.

The first way of making Crocus Martis is as follows.
Take very fine filings of iron, or those of steel which are better, mix them in a crucible, with three parts of powdered brimstome, laid layer upon layer; calcine them for four hours by a very strong fire, till the sulphur is consum'd; then take the crucible out of the fire, and let the matter cool; then grind it to a very fine powder, and searce it through a very fine sieve; then put that powder into a crucible, and lute it well, and set it into the mouth of a reverberatory furnace for the space of fifteen days or more; and of the jà colour it was before, it will become a very deep red, almost like a purple. Keep it in a very close vessel for the use of glass colours; it will work many wonderful effects.

Another way of making CROCUS MARTIS for colouring of glas.
Though this way of making Crocus Martis be very easy, yet it deserves to be esteem’d, since it tinges glass of the true blood red colour. It is prepar'd as follows.
Take filings of iron, or (which is better) steel, put them into earthen pans with strong vinegar; mix them well, but only sprinkling them so much, that they may be thoroughly wet; spread them abroad in the pans, and set them in the sun to dry, or if the sun be obscur'd by clouds, set them in the open air; then powder them, and sprinkle them again with vinegar, and dry them again as before; then powder them again, repeating this operation eight times; at the last, grind and searce them well, and you will have a very fine powder of the colour of beaten brick, which keep in close vessels for use.
This Crocus Martis thus made with vinegar, complies very much with greens and the emerald colour of glass of lead. It is us'd also in pastes for the same colour with verdigrease, and in blacks.

Another CROCUS MARTIS with aqua fortis.
Put fine filings of iron or steel into well glaz'd earthen pans, sprinkle them with aqua fortis, and set them to dry in the sun, and then reduce them again into powder, and repeat this process several times, as in that made with vinegar; and when it has obtain’d a good red colour as before, powder it, searce, and keep it in a glass vessel close stopp'd for use.
By this the red colour of iron is made more manifest in glass, and is so very resplendent and bright, that it seems almost incredible, but that experience has shewn it.

A CROCUS MARTIS with aqua regalis.
Dissolve filings of iron or steel in a glass body well covered in aqua regalis, that is, in aqua fortis made aqua regalis with sal armoniac. See aqua regalis.
Keep them so for three days, stirring them every day well, during which you may add fresh filings by little and little; in doing which you must be very cautious, for it riseth so much by fermentation in the aqua regalis, that it will endanger the breaking the glass or running over.
After three days, set the cucurbit on a gentle fire, that all the water may evaporate, till it leaves the Crocus behind dry, and it will be admirable for tinging glass, and perhaps the best of all; because in the former you cannot find such diversities of colours as in this.

Another method of making CROCUS MARTIS.
Though this is an easy method, it will make a Crocus of no less beauty and vertue than the former.
Take filings of iron or sleel without any rust, let them stand in a reverberatory furnace with a very strong fire; the heat being at least to the fourth degree, till it becomes of the colour of purple.
Then take it out of the fire, and let it stand by to cool, and then put it into a vessel full of water, and stir it briskly about, and then presently pour off the water into another vessel, which you may also repeat.
Thus there will remain in the first vessel the iron that is not calcin'd, which, if you please, you may put again into a reverberatory furnace.
In the second vessel there will be the Crocus, which set over a gentle fire to evaporate the water.
But you must not decant off the water, tho' it does appear clear, after it has settled to the bottom; yet the water contains the most subtle parts of it imperceptibly suspended in it. Having well evaporated the water, you will have a very red powder, very fine and extraordinary, which keep for use.

Another way of making CROCUS MARTIS.
This last way will be of some use to those who shall desire to have the iron or steel granulated, or in little drops, the metal whereof is difficult to melt.
Take a bar of either of the metals of five or six pounds weight, heat it as hot as is possible in a smith's forge, so that it may sparkle when it comes out of the fire.
At the same time some other person must have a long stick of brimstone ready, and large too, which will be best for this operation, which immediately upon the metals coming out of the fire, they must be thrust one against the other over a great earthen pan full of warm water, into which the metal will drop in small drops or granuli, melting like wax when touch'd by the sulphur.
When this has been done, lay them layer by layer in a crucible with powdered brimstone, and then set them in a reverberatory fire, where they will be reduc’d to a red powder, which grind and scarce and keep for use.

The method of making CROCUS VENERIS.
Take as much ÆS USTUM as you please, add to it its weight of green verdegrease, and as much sal armoniac fix’d and sufil; pound the whole well together, and dry them over the fire in a large iron shovel; then into the shovel pour lee of urine, and make the whole boil till, the lee be intirely consum’d; then put on more of the same lee, boil it again till the lee be consum’d as before, and repeat this a third time.
Then pound or grind this mixture, and put it into a reverberatory that it may calcine well; then pound it again till 'tis reduc’d to an impalpable powder, and put it into an earthen glaz'd pot; pour upon the same lee of urine, wherein you dissolve it, viz. to each pound of lee put four ounces of sal armoniac fix’d and fusile.
Then boil the whole over a gentle fire in ashes for the space of a quarter of an hour; then decant off that lee into some proper vessel, for that will contain the tincture of the acs usium, and of the green, which it has extracted.
Then put more lee upon the matter, and boil it a quarter of an hour more over the same fire; then decant off that lee to the former: continue thus to water it with fresh lee, and decant it off to the former, as long as it will extract any lee from the matter.
Then take all these tinctured lees, and filter them through whited brown paper; then evaporate three quarters over a gentle fire.
Put the remainder into an alembick, with the helm (or head) on, and the receiver, and distil it till it be dry; then will you find at the bottom of the alembick, a Crocus Veneris of a very wonderful virtue for colouring glass, &c.

Another easier way of making CROCUS VENERIS.
Take very thin plates of copper, put them into an earthen pot with common salt, layer upon layer; put this pot on the furnace, where let it stand till the matter be very red; then put the plates with the salt into cold water, and wash them well to take away all blackness.
Repeat the laying of these plates with common salt, calcining them at the fire, and washing them as before, as often as you please. After the last time, pour warm water on that, wherein the plates have been extinguish'd, and let it stand for some time; then empty it, and you will find at the bottom of the vessel a Crocus Veneris as red as blood. Wash it well several times to cleanse it, and dry it well with a linen cloth, and keep it for use for colouring glass.
There are some who content themselves with taking as usium, prepared with sulphur and common salt, heating it red hot in the fire nine times, and quenching it as often in linseed oil; and then dry it and powder it.

Another easy way of making CROCUS VENERIS.
Take of copper simply calcin'd (see COPPER to calcine) one part, of sulphur vivium eight parts; powder them well, and mix them together in a large crucible; set it into a coal fire in a little furnace, stirring the matter continually with an iron rod, till the sulphur be consum’d; repeat this operation five or six times, then cast it thus refin’d into an iron pan of boiling water; stir it often with a stick, while the calx descends to the bottom; then the water being settled and clear, evaporate it to three fourths, to extract the crystals; or rather evaporate the whole, and you will find at the bottom of the vessel a Crocus Veneris very fine and red.