that if we, the said Edward Heylyn and Thomas Frye, should not particularly describe and ascertain the nature of our said Invention, and in what manner and of what materials the same was to be performed, by an instrument in writing, under our hands and seals, or the hand and seal of one of us, and cause the same to be inrolled in His Majesty’s High Court of Chancery, within four calendar months after the date of the said recited Letters Patent; that then the said Letters Patent, and the libertys and advantages thereby granted, should cease and be void, as in and by the same Letters Patent (relation being thereunto had) may more at large appear. “NOW KNOW YE, that we, the said Edward Heylyn and Thomas Frye, in pursuance of the said provisoe, contained in the said recited Letters Patent, do hereby describe and ascertain the nature of our said Invention, and the manner and of what material the same is to be performed, as hereinafter is mentioned (that is to say):-- “The material is an earth, the produce of the Chirokee nation in America, called by the natives unaker, the propertys of which are as follows, videlicet, to be very fixed, strongly resisting fire and menstrua, is extreamly white, tenacious, and glittering with mica. The manner of manufacturing the said material is as follows:--Take unaker, and by washing seperate the sand and mica from it, which is of no use; take pott ash, fern ash, pearl ash, kelp, or any other vegetable lixiviall salt, one part of sands, flints, pebbles, or any other stones of the vitryfying kind; one other part of these two principles form a glass in the usual manner of making glass, which when formed reduce to an impalpable powder. Then mix to one part of this powder two parts of the washed unaker, let them be well worked together until intimately mixed for one sort of ware; but you may vary the proportions of the unaker and the glass; videlicet, for some parts of porcelain you may use one half unaker and the other half glass, and so in different proportions, till you come to four unaker and one glass; after which knead it well together, and throw it on the wheel, cast it into moulds, or imprint it into utensils, ornaments, &c.; those vessells, ornaments, &c., that are thrown, should be afterwards turned on a lathe and burnished, it will then be in a situation to be put into the kiln and burned with wood, care being taken not to discolour the ware, otherwise the process will be much hurt. This first burning is called biscuiting, which, if it comes out very white, is ready to be painted blue, with lapis lazuli, lapis armenis, or zapher, which must be highly calcined and ground very fine. It is then to be dipt into the following glaze:--Take unaker forty pounds, of the above glass ten pounds, mix and calcine them in a reverberatory; then reduce, and to each pound when