484 



BOOK X. 



A — Pestle with teeth. B — Pestle without teeth. C — Dish or tray full of ashes. 

 D — Prepared tests placed on boards or shelves. E — Empty tests. F — Wood. 



G — Saw. 



little powder is again moistened, and thrown into the test, and tamped ; this 

 work is repeated until the test is entirely full of the powder, which the 

 master then cuts out with a knife, sharp on both sides, and turned upward at 

 both ends so that the central part is a palm and a digit long ; therefore it is 

 partly straight and partly curved. The blade is one and a half digits wide, 

 and at each end it turns upward two palms, which ends to the depth of a 

 palm are either not sharpened or they are enclosed in wooden handles. The 

 master holds the knife with one hand and cuts out the powder from the test, 

 so that it is left three digits thick all round ; then he sifts the powder of dried 

 bones over it through a sieve, the bottom of which is made of closely-woven 

 bristles. Afterward a ball made of very hard wood, six digits in diameter, 

 is placed in the test and rolled about with both hands, in order to make the 

 inside even and smooth ; for that matter he may move the ball about with only 

 one hand. The tests*" are of various capacities, for some of them when prepared 



^'The refining of silver in " tests " (Latin testa) is merely a second cupellation, with 

 greater care and under stronger blast. Stirring the mass with an iron rod serves to raise the 

 impurities which either volatilize as litharge or, floating to the edges, are absorbed into the 

 " test." The capacity of the tests, from 15 librae to 50 librae, would be from about 155 to 

 515 ozs. Troy. 



