touch-needle

1 definition found

touch-needle - Collaborative International Dictionary of English v.0.48 :

  Touch-needle \Touch"-nee`dle\, n. (Metal.)
     A small bar of gold and silver, either pure, or alloyed in
     some known proportion with copper, for trying the purity of
     articles of gold or silver by comparison of the streaks made
     by the article and the bar on a touchstone.
     [1913 Webster]