a set of needles of gold or silver alloy of known compositions, used in testing other alloys on a touchstone
试金针(由已知成分的金合金或银合金制成的针,可在试金石上检测其他合金)。
pl-n. 试金针
If there is no touch, it is impossible fallen needles.
如果没有任何碰触,针头是不可能掉落的。
a set of needles of gold or silver alloy of known compositions, used in testing other alloys on a touchstone
试金针(由已知成分的金合金或银合金制成的针,可在试金石上检测其他合金)。