Abstract: The invention provides a method by which a crystal glass composition which employs TiO.sub.2 as a raw material substituted for PbO can be produced while effectively preventing development of a yellowish color of the glass composition which is caused by TiO.sub.2. In the production method, to a batch composition which is composed of 50 to 60 percent by weight of SiO.sub.2, 4 to 14 percent by weight of K.sub.2 O, 10 to 20 percent by weight of BaO and 3 to 10 percent by weight of TiO.sub.2, NaNO.sub.3 (sodium nitrate) is added by 1.0 to 5.0 percent by weight or BaO.sub.2 (barium peroxide) is added by 0.3 to 2.0 percent by weight for elimination of development of a color which arises from the 3 to 10 percent by weight of TiO.sub.2, and also one of Sb.sub.2 O.sub.3 (antimony oxide) and As.sub.2 O.sub.3 (arsenious acid) is added by 0.2 to 1.0 percent by weight for defoaming. Instead, NaSb(OH).sub.6 (sodium antimonate) having color development elimination and defoaming actions may be added by 0.5 to 2.

Abstract: A glass composition is disclosed wherein the density and the refraction index and the dispersion value of light are equal to or higher than those of conventional lead-containing crystal glass while no lead is contained therein at all. The glass composition comprises 50 to 60% by weight of SiO.sub.2, 5 to 13% by weight of K.sub.2 O, 5 to 8% by weight of TiO.sub.2, 10 to 15% by weight of BaO, 5 to 10% by weight of ZnO, 3 to 10% by weight of Na.sub.2 O, 1 to 5% by weight of CaO, and 0.3 to 0.8% by weight of Sb.sub.2 O.sub.3.

Abstract: A metal-containing indoaniline compound having the formula: ##STR1## wherein M is a metal atom of Group VIII, Ib, IIb, IIIb, IVa, Va, VIa or VIIa of the Periodic Table or its halide or oxide, rings A, B, C, D, E and F may have substituents, each of K.sup.1 K.sup.2 and K.sup.3 is a residue of a substituted or unsubstituted aromatic amine, each of l, m and n is 0 or 1, provided l+m+n=2 or 3, and p is 2, 3 or 4.