FRIIT, a mixture of several substances intended to be fused together for the purpose of making glass. After these substances have been mixed together, they are generally exposed during a certain time to a more or less strong heat, which is, however, incapable of completely fusing them. The intention of this operation is either to effect a slight union betwixt these matters, or to free them more perfectly from any inflammable or extraneous matter, by this calcination.