Quartz

A mineral, silica, SiO2. It has recently been used by C. V. Boys and since by others in the making of filaments for torsion suspensions. The mineral is melted, while attached to an arrow or other projectile. It is touched to another piece of quartz or some substance to which it adheres and the arrow is fired off from the bow. A very fine filament of surpa ingly good qualities for galvanometer suspension filaments is produced. As a dielectric it is remarkable in po e ing but one-ninth the residual capacity of gla .