Book III.

Of MINERALS.

5«3

reduc'd into a Pafte, what Figure or Formyou pleafe may be given to it, and when it iscold it becomes as hard as a Stone.

Some make this Sugar Alum enter theCompofition of their Fucus's.

There is moreover other Sorts of Alum,namely that which is in a white tranfparentStone, in every particular almoft like theCryftal Rock Alum, and to which the Nameof Scayolle Alum is given, or that of Mufcovy

long fince great Quantities of this Sort ofAlum was found in the Clayey Earth of Puffy.There are others that make ufe of anotherSort of Mufcovy Glafs , which we call Gipor Plaifter ; Potatoes alfo have obtain'd theName of Alum Catin, as is obfery'd in itsPlace.

Some fay the Name of Alum is deriv'Jfrom the Latin, Lumen, which fignifiesLight, becaufe Alum gives a Luftre, or Bright-

Glafs, which is found in the Quarries of nefs to died Colours, and that without it

Paffy, and which after it is calcin'd is of a there wou'd be no dying or colouring to any

very beautiful White j but that of it which Purpofe.is counterfeited is more like Plaifter, not

End of the Third BO OK of Minerals.

■ I !*!■!■ ■■ M-

BOOK

..»-.