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The production of slave (trade) beads became so popular that literally tons of these beads were used for this purpose. Beads were used as ballast in slave/trade ships for the outbound trip. The beads and other trade items were exchanged for human cargo as well as ivory, gold, and other
Roman gold glass beads were made by using an inner tube or rod to which the gold leaf was stuck. A larger tube was slid over that and the beads crimped off. Easily transported and very attractive, Roman gold glass beads have been found as far outside the Empire as the Wari-Bateshwar ruins in Bangladesh, and sites in China, Korea, Thailand and ...
Sugar glass is made by dissolving sugar in water and heating it to at least the "hard crack" stage (approx. 150 °C / 300 °F) in the candy making process. Glucose or corn syrup is used to prevent the sugar from recrystallizing and becoming opaque, by disrupting the orderly arrangement of the molecules.
– gold hydrazide, formed by adding ammonia to the auric hydroxide. When dry, can explode on concussion. – an unstable gold carbonate formed by precipitation by potash from gold dissolved in aqua regia. Galena – lead(II) sulfide. Lead ore. Glass of antimony – impure antimony tetroxide, SbO 4 formed by roasting stibnite. A yellow pigment ...
A very important advance in glass manufacture was the technique of adding lead oxide to the molten glass; this improved the appearance of the glass and made it easier to melt using sea-coal as a furnace fuel. This technique also increased the "working period" of the glass, making it easier to manipulate.
The gold may then be further refined by gold parting, which removes other metals (principally silver) by blowing chlorine gas through the molten metal. Historically, small particles of gold were amalgamated with mercury, and then concentrated by boiling away the mercury. The mercury method is still used in some small operations.
Panning for gold was the simplest method of recovering gold, but mostly used for prospecting since it was slow. A faster way was by a rocker box or by sluicing. Dirt was filled into the box or sluice together with water and rocking movements or gravity would make the gold particle go to the bottom whereas sand and fine gold particles would flow ...
The first and most common of these is to use two frames of glass and seal the edges with cloth tape. However, this method presents many risks to the object. One of these risks is this method opens the door for the object to be in contact with heat and moisture, which would also make the object's surface to stick to the glass. [3]