SDoctttneof^tualttte^ 27 



which are ufually made of calcin'd 

 Tin (which the Tradefmen call Put- 

 tee,*) colliquated with the Ingredienfs 

 of Cryftal-glafs and Tome fmall por- 

 tion of Mineral pigment. But though 

 in ail the above-named brittle bodies, 

 Tin be a considerable Ingredient} yet 

 'twere very unadvifed to affirm, that 

 Brittlenefs in general proceeds from 

 Tin. For provided the folid parts of 

 confiftent bodies touch one another 

 but according to fmall portions of 

 their furfaces, and be not implicated 

 by their contexture, the Metalline or 

 other Compolition may be brittle, 

 though there be no Tin at all in it. 

 And in efFe&, the materials of glals 

 being brought to fufion willcompofe 

 a brittle body, as well when there is 

 no Puttee colliquated with them^ as 

 when there is. Calcin'd Lead by the 

 aftion of the fire may be melted into 

 a brittle mafs, and even into tranfpa- 

 rent Clafs 5 without the help of Tin 

 or any other additament. And I need 

 pot addj that there are a multitude of 

 other bodies^ that cannot be pretend- 

 ed 



