Dictionarium polygraphicum. Brass.

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.
Brass, or as the French call it, yellow copper, is a factitious metal made of copper and lapis calaminaris.

The method of preparing it is as follows. The lapis having been calcin'd, and ground fine as flour, is mix’d with ground charcoal; and incorporated, by means of water, into a mass: this being done, about seven pounds of the lapis calaminaris is put into a melting-pot that will contain about a gallon; and over that about five pounds of copper; this pot is let down into a wind-furnace eight foot deep, where it remains for eleven hours, in which time it is converted into brass.

This metal then is cast either into plates or lumps; forty five pounds of crude lapis calaminaris or calamine, will produce thirty pounds when calcin'd or burnt.

Sometimes brass-shruff is us'd instead of copper; but that is not always to be procur'd in quantities sufficient, it being no other than a collection of old brass.

Pure brass is not malleable, unless when it is hot; for when it is cold, it will break. And after it has been melted twice, it will be no longer in a condition to bear the hammer at all; but in order to render it capable of being wrought, they put seven pounds of lead to a hundred pounds of brass, which renders it more soft and pliable.

The best proportion for gun-metal for casting great guns is said to be a thousand pounds of copper, nine hundred pounds of tin, and six hundred pounds of brass in eleven or twelve thou sand weight of metal.

The best brass guns are made of malleable metal, not of pure copper and calamine alone; but coarser metals are us’d to make it run closer and sounder, as lead and pot-metal, which last is made of brass and lead; twenty pound of lead is usually put into a hundred pounds of pot metal.

Corinthian brass has been famous in antiquity, and is a mixture of gold, silver, and copper. L. Mummius having sack'd and burnt the city of Corinth, 146 years before our saviour's time, there being there a vast number of statues, images, vessels, &c. of gold, silver, and copper, all these melted and run together by means of the violence of the conflagration; and this mixture was the composition call'd Corinthian brass. Those who peak of it accurately, distinguish it into three kinds; in the first, gold is the prevailing metal; in the second, silver; in the third, gold, silver, and copper are equally blended.

To make BRASS.
Melt fix pounds of copper with two pounds of lapis calaminaris in powder for the space of an hour, and then put it out.

To cleanse BRASS.
Take aqua fortis and water, of each a like quantity; shake them together, and with a woollen rag dipt therein, rub it over; then presently rub it with an oily cloth: lastly, with a dry woollen cloth, dipt in lapis calaminaris, and it will be as clear and bright as when new.

To purge BRASS.
It is cleansed or purged by casting into it while it is melted, broken glass, tartar, sal armoniack and salt petre, each of them by turns, a little and a little.

To calcine BRASS, call’d Orpello or Tremolante, making a curious sea-green or sky-colour.
Take thin Brass, cut into small pieces, put it into a crucible covered and luted at top; set it in a fierce fire, where let it stand four days in a great (but not melting) fire, for if it melt, your labour is lost. In four days time it will be very well calcin'd; then powder'd as fine as you possibly can, searse it, and the powder will be black; spread this on tiles, and keep a leer on burning coals for four days, near to the round hole; take away the ashes that fall upon it, powder and searse it again, and then keep it close stopt for use.
To know if it be well calcin'd, put it into glass, and if it swells, ’tis right; if not, it is not well calcin'd, or else it is over burnt, and if so, it will not give a good colour.

To calcine BRASS another way, to make a transparent RED.
Cut your thin pieces of brass small, and put it into a melting pot, with layers of powder of brimstone, and metal as in copper. Set it first on kindled coals, then put it into a strong fire in the furnace to calcine for twenty four hours; then beat it to a fine powder, and searse it; put it covered into the furnace on earthen tiles for twelve days, to reverberate; so powder, grind, and keep it for use.
Besides a red, it contributes principally to the making a yellow and chalcedony.

A RED colour from BRASS.
Put small pieces of it into the arches of the furnace, and let them remain there close till they are well calcin'd; but in such a fire, that they may not melt; and when they are well calcin'd, powder the brass, and the powder will be red, and excellent in many uses for colouring glass.
Brass thrice calcin'd is likewise very excellent.

To calcine BRASS thrice.
Put this into the leer, or into the furnello of the furnace, near the occhio, into pans baked or earthen tiles; calcine it for four days, and you will have a black powder sticking together; pound it fine, and searse it; then calcine it again as before, but a day longer, and then it will not stick together, and will be of a russet colour; and do so the third time, but take care that it be not calcin’d either too much or too little, for then it will not give a good colour.
To know if it be well calcin'd, put it to purified metal, and it will make it boil and swell; and if it does not, it is either too much or too little.
This makes a curious sea-green, and an emerald-green, a turquois or sky colour, and other varieties.

BRASS to tinge of a gold colour.
Dissolve burnt brass in aqua fortis (made of vitriol, salt-petre, alum, verdigrease and vermilion) and then reduce it again, and it will be much of a gold colour.

To make BRASS thorough white.
Heat brass red hot, and quench it in water distill'd from sal armoniack and egg shells ground together, and it will be very white.

Another way.
Calcine egg-shells in a crucible, and temper them with the whites of eggs; let it stand so three weeks; heat the brass red hot, and put this upon it.

The way to colour BRASS white.
Dissolve two penny weight of silver in aqua fortis, setting it to the fire in a vessel till the silver turn to water; to which add as much powder of white tartar as may drink up all the water, make it into balls, with which rub any brass, and it will be as white as silver.

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