Description of the Most Principal Mineral Ores

the wire or the iron rails / with which the furnace is bound / can lie. Then let it dry very well in the sun / and burn hard in a potter’s or brick kiln.

Assaying furnaces of strong armor plate.

Furthermore, assaying furnaces are also made in the same form / which are square on the outside / formed like the assaying furnace just mentioned / made very neatly and cleanly of strong armor plate / and riveted on the inside with iron bars / to which the clay can adhere / and thus skillfully put together / that one can also unscrew such a furnace / into five pieces / and take it apart / which then also on the inside / like the previous assaying furnace made together of plate / is neatly lined with good permanent clay / and sliding shutters should be made on the strong plate on the outside of the furnace / which one can slide back and forth in small grooves / and thus according to the situation / can regulate the assays well therein / Much is thought of such assaying furnaces / but nothing more can be accomplished with them / than in the other furnaces mentioned / if only an assayer / has the knowledge of the fire / according to which he should regulate all assays / So he can without doubt / perform them correctly in any assaying furnace. How now this / and all other aforementioned assaying furnaces / are to be formed / can be seen in the following figure.