COMPOUNDING OF METALS. 391 



when it cooletli ; for this stupifieth the quicksilver that 

 it runneth no more. This trial is to be advanced three 

 ways. First, by iterating the melting of the lead, to 

 see whether it will not make the quicksilver harder and 

 harder. Secondly, to put realgar hot into the midst of 

 the quicksilver, whereby it may be condensed as well 

 from within as without. Tliirdly, to try it in the midst 

 of molten iron, or molten steel, which is a body more 

 likely to fix the quicksilver than lead. It may be also 

 tried, by incorporating powder of steel, or coppel dust, 

 by pouncing into the quicksilver, and so to proceed to 

 the stupifying. 



Upon glass four tilings would be put in proof. The 

 first, means to make the glass more crystalline. The 

 second, to make it more strong for falls, and for fire, 

 though it come not to the degree to be malleable. The 

 third, to make it coloured by tinctures, comparable [to] 

 or exceeding precious stones. The fourth, to make a 

 compound body of glass and galletyle ; that is, to have 

 the colour milky like a chalcedon, being a stuff between 

 a porcelane and a glass. 



For the first ; it is good first to know exactly the 

 several materials whereof the glass in use is made ; 

 window glass, Normandy and Burgundy, ale-house 

 glass, English drinking glass : and then thereupon to 

 consider what the reason is of the coarseness or clear- 

 ness ; and from thence to rise to a consideration how to 

 make some additaments to the coarser materials, to 

 raise them to the whiteness and crystalline splendour 

 of the iiiic>t. 



For the second; we see pebbles, and some other 

 stones, will cut as fine as crystal, which if they will 



