Abstract: The electric incandescent lamp has a quartz glass lamp vessel (1) or envelope (4') around the lamp vessel, which has a red coloured dope in the area at the side of the incandescent body (3). The quartz glass with red dope contains samarium.sup.II oxide, aluminium oxide, titanium dioxide, and silicon dioxide, the analysis of the glass in its oxidized form being Sm.sub.2 O.sub.3 1 to 3% by weight, Al.sub.2 O.sub.3 up to 3% by weight, TiO.sub.2, rest SiO.sub.2, the molar ratio Al/Sm being at least about 2 and the molar ratio Sm/Ti being from 2 to 8.

Abstract: The electrodeless low pressure sodium vapour discharge lamp which has a discharge vessel (1) containing sodium vapour and inert gas. The discharge vessel (1) has an enveloping part (10) and connected therewith at a first end of the discharge vessel (1) a sunken part (20). In the sunken part (20) is a body (30) of soft-magnetic material which is surrounded by an electric coil (31). The discharge vessel (1) is enclosed in an outer bulb (40). The inner surface (2) of the discharge vessel (1) has a layer (4) of borate glass. The borate glass which covers the sunken part (20), is sintered. The invention renders it possible to make parts of construction glass which have a layer of borate glass at an outer surface.

Abstract: Luminescent terbium-activated alkaline earth metal rare earth metal borate having a monoclinic crystal structure and being defined by the formula M.sub.3 Ln.sub.1-x Tb.sub.x (BO.sub.3).sub.3 in which M is at least one of the elements Ba, Sr and Ca of which up to 34 mol % may be replaced by Mg, in which Ln is at least one of the elements La, Gd, Y and Sc and in which 0.005.ltoreq.x.ltoreq.1.

Abstract: Method of preparing a luminescent Eu.sup.2+ activated strontium aluminate defined by the formula Sr.sub.4 Al.sub.14 O.sub.25 :Eu.sup.2+ in which per mol of the Al present a combination of between 0.1 and 5 mol % of B.sub.2 O.sub.3 or compounds yielding B.sub.2 O.sub.3 upon an increase of temperature, and between 0.1 and 10 mol % of at least one of the fluorides and/or chlorides of Ba, Sr, Cs and/or Al and/or RbCl as a flux to a mixture comprising SrO, Al.sub.2 O.sub.3 and Eu.sub.2 O.sub.3 or compounds yielding these oxides upon an increase of temperature, whereafter the mixture is subjected to a first heat treatment in a weekly reducing atmosphere at 1100.degree. to 1500.degree. C. Between 0.1 and 10 mol % of at least one of the ammonium halogenides is added per mol of the Al present to the product thus obtained, and the mixture thus obtained is subsequently subjected to a second heat treatment at a temperature of 700.degree. to 1200.degree. C.