Journal of the American Ceramic SocietyKurkjian and Prindle Vol 8I. No 4 Glass is much significant advances in the discovery and isolation of new el more gentile, graceful ements, and, in the 1830s, Harcourt began investigations of the effects of many of these new elements on the optical properties long the elem and noble than any cadmium, fluorine, lithium, magnesium, molybdenum, tungsten, uranium, and vanadium. He also studied the Metall It is more effects of other elements, including antimony, arsenic, barium, boron, phosphorus, tin, and zinc, first introduced into glass by delightful, polite, and but also melted some phosphates, borates, and titanates, in part sightly than any other neous glass. He did not widely publicize his findings, but Sir George Stokes, the noted mathematician and physicist, learned of his work, collaborated with him, and helped to bring the material at this day results to the attention of the scientific community in 1871, the ear of Harcourts death. In 1874. Stokes made a small. three- known to the world omponent lens that was largely free of the secondary spectrum from some of Harcourts glasses. Therefore, even though Har Antonio neri. 1612 courts glasses were not completely homogeneous, his work demonstrated that different glassmaking ingredients did bring changes in dispersion and refractive index that could yield glasses that began to solve the optical problems of the time.16,31,39 beyond those of ordinary crown and flint glasses if better lenses were to be made that corrected the secondary spectrum. Fraun- British glass industry to investigate further the effects of dif- ferent glass constituents, it did little beyond the production of was probably the discoverer of the mixed-alkali effect, noting some standard optical crowns and flints by Chance Brothers in that glasses with mixed alkalis had superior durability. (The irmingham. Experimentation to develop new glas served in some properties when one alkali ion is gradually tions was severely constrained at that time in England by ex- substituted for another alkali ion. This phenomenon is observed orbitant taxes on all glassmelting. Therefore, Chance Brothers in properties affected by transport mechanisms, such as ele concentrated instead on improving the quality of the standare trical conductivity, dielectric loss, internal friction, and self- glasses by stirring the I nelt. Accordingly, the initiative in glass diffusion. )Later, Fraunhofer's spectral studies enabled him to composition research passed to German glassmakers, who built on the work of fraunhofer and harcourt 31 make observations on dispersion for the principal glass com- ponents of the day 17, 22,25,35,36 As is evident from the foregoing, until the late 19th century Impressed by Fraunhofer's results, the Royal Society estab- he development of new glasses was largely a matter of ar lished, in 1824, a commission consisting of Michael Faraday occasional fortuitous discovery. These early investigations, al John Herschel( the astronomer), and George Dollond(another though often motivated by a need, were not pursued of the famed clan of opticians), to study the possibility of atically, had difficulty in yielding a homogeneous prod exce on of Harcourts work, usually used the same making superior glasses for telescope objectives. Faraday be w dients hovestadt wrote. in 1900 el came interested in glassmelting and made some prolonged in ment of the art of glassmaking in response to optical require of melting glasses in platinum containers and the importance of fluxes broke the monotony of a uniform series of crowns and tiring melts to improve homogeneity. His experiments, un- flints. 740 fortunately, did not contribute much to the knowledge of glass omposition, although he did demonstrate that boron could be Ised in glassmaking to make a passable lead borosilicate flint llL Abbe and Schott lass. Faraday later(1845)conducted some experiments of which he demonstrated the Faraday effect(rotation of the plane a microscope maker at the university. Similar to the telescope of polarization of light in a magnetic field ). 15,33,35, 37,38 makers, Abbe soon realized that a wider variation in dispersion It may seem surprising today that eminent scientists and for a given refractive index was needed to remove completely intellectuals of the time were deeply interested in finding so- states,Goethe, then Prime Minister of a German duchy. in of Otto Schott, a young German chemist who had been explor- University of Jena, it would be most important to determine ing glassmelting phenomena in connection with his family' the relation of refraction and dispersion in your (barium and glassworks in Westphalia. Schott contacted Abbe and sent him strontium glasses 6 should be pleased to contribute the samples might aid Abbe in his research for glasses with dif- of a wide range of elements on the properties of glass was the laborating and thus was born one of the greatest and most Schott moved to Jena in 1882 to be closer to abbe and Zeiss Abbe(the scientist), Schott(the glassmaker), and Zeiss(the instrument builder) worked together in a synergistic manner that bore dramatic results. abbe and Schott d discuss the tThe poem on the 就运 composition changes to be made, Schott would then prepare homogeneous glass melts, and Abbe would measure the results If the properties appeared to be an improvement, Zeiss would grind and polish lenses and observe the performance of thebeyond those of ordinary crown and flint glasses if better lenses were to be made that corrected the secondary spectrum. Fraun￾hofer also wrote about the chemical durability of glasses and was probably the discoverer of the mixed-alkali effect, noting that glasses with mixed alkalis had superior durability. (The mixed-alkali effect is the distinctly nonlinear behavior ob￾served in some properties when one alkali ion is gradually substituted for another alkali ion. This phenomenon is observed in properties affected by transport mechanisms, such as elec￾trical conductivity, dielectric loss, internal friction, and self￾diffusion.) Later, Fraunhofer’s spectral studies enabled him to make observations on dispersion for the principal glass com￾ponents of the day.17,22,25,35,36 Impressed by Fraunhofer’s results, the Royal Society estab￾lished, in 1824, a commission consisting of Michael Faraday, John Herschel (the astronomer), and George Dollond (another of the famed clan of opticians), to study the possibility of making superior glasses for telescope objectives. Faraday be￾came interested in glassmelting and made some prolonged in￾vestigations during 1825–1830 that demonstrated the benefits of melting glasses in platinum containers and the importance of stirring melts to improve homogeneity. His experiments, un￾fortunately, did not contribute much to the knowledge of glass composition, although he did demonstrate that boron could be used in glassmaking to make a passable lead borosilicate flint glass. Faraday later (1845) conducted some experiments of significance with his ‘‘heavy glass’’ (see glass 7 in Table I), in which he demonstrated the Faraday effect (rotation of the plane of polarization of light in a magnetic field).15,33,35,37,38 It may seem surprising today that eminent scientists and intellectuals of the time were deeply interested in finding so￾lutions to glass composition problems. For example, Vogel states, ‘‘Goethe, then Prime Minister of a German duchy . . . in 1829 wrote to his friend, the noted chemist Do¨breiner at the University of Jena, ‘it would be most important to determine the relation of refraction and dispersion in your [barium and strontium] glasses . . . I should be pleased to contribute the modest funding . . .’.’’36,‡ The first, however, to make an extensive study of the effects of a wide range of elements on the properties of glass was the Rev. William Vernon Harcourt, an English clergyman. The late 18th century and the early 19th century was a period of highly significant advances in the discovery and isolation of new el￾ements, and, in the 1830s, Harcourt began investigations of the effects of many of these new elements on the optical properties of glass. Among the elements he first used in glass were be￾ryllium, cadmium, fluorine, lithium, magnesium, molybdenum, nickel, tungsten, uranium, and vanadium. He also studied the effects of other elements, including antimony, arsenic, barium, boron, phosphorus, tin, and zinc, first introduced into glass by others. Harcourt did not confine his studies to silicate glasses, but also melted some phosphates, borates, and titanates, in part because he found it difficult to fuse the silicates to a homoge￾neous glass. He did not widely publicize his findings, but Sir George Stokes, the noted mathematician and physicist, learned of his work, collaborated with him, and helped to bring the results to the attention of the scientific community in 1871, the year of Harcourt’s death. In 1874, Stokes made a small, three￾component lens that was largely free of the secondary spectrum from some of Harcourt’s glasses. Therefore, even though Har￾court’s glasses were not completely homogeneous, his work demonstrated that different glassmaking ingredients did bring changes in dispersion and refractive index that could yield glasses that began to solve the optical problems of the time.16,31,39 Although the work of Harcourt should have encouraged the British glass industry to investigate further the effects of dif￾ferent glass constituents, it did little beyond the production of some standard optical crowns and flints by Chance Brothers in Birmingham. Experimentation to develop new glass composi￾tions was severely constrained at that time in England by ex￾orbitant taxes on all glassmelting. Therefore, Chance Brothers concentrated instead on improving the quality of the standard glasses by stirring the melt. Accordingly, the initiative in glass composition research passed to German glassmakers, who built on the work of Fraunhofer and Harcourt.31 As is evident from the foregoing, until the late 19th century, the development of new glasses was largely a matter of an occasional fortuitous discovery. These early investigations, al￾though often motivated by a need, were not pursued system￾atically, had difficulty in yielding a homogeneous product, and, with the exception of Harcourt’s work, usually used the same few ingredients. Hovestadt wrote, in 1900, ‘‘. . . the develop￾ment of the art of glassmaking in response to optical require￾ments kept, for a long time, to one narrow groove, and no new fluxes broke the monotony of a uniform series of crowns and flints.’’40 III. Abbe and Schott Ernst Abbe, professor of physics at Jena University, became interested in optical glasses through his work with Carl Zeiss, a microscope maker at the university. Similar to the telescope makers, Abbe soon realized that a wider variation in dispersion for a given refractive index was needed to remove completely the secondary spectrum from optical images. He wrote on the subject in the late 1870s, and his remarks attracted the interest of Otto Schott, a young German chemist who had been explor￾ing glassmelting phenomena in connection with his family’s glassworks in Westphalia. Schott contacted Abbe and sent him some lithium glasses he had prepared with the thought the samples might aid Abbe in his research for glasses with dif￾ferent optical properties. By 1881 Abbe and Schott were col￾laborating and thus was born one of the greatest and most productive associations in the history of glass composition.31,40 Schott moved to Jena in 1882 to be closer to Abbe and Zeiss. Abbe (the scientist), Schott (the glassmaker), and Zeiss (the instrument builder) worked together in a synergistic manner that bore dramatic results. Abbe and Schott would discuss the composition changes to be made, Schott would then prepare homogeneous glass melts, and Abbe would measure the results. If the properties appeared to be an improvement, Zeiss would grind and polish lenses and observe the performance of the ‡ The poem on the previous page was authored by Roald Hoffman, the Nobel Laureate in chemistry in 1981 with Kenichi Fukui for ‘‘His application of molecular orbital theory to chemical reactions.’’ Also, the 1977 Nobel Prize in physics was awarded to P. W. Anderson, Sir N. F. Mott, and J. H. van Vleck for ‘‘Their funda￾mental theoretical investigations of the electronic structure of magnetic and disor￾dered systems.’’ The eminent scientists continue to find glassy systems of interest. ‘‘Glass . . . is much more gentile, graceful, and noble than any Metall, . . . it is more delightful, polite, and sightly than any other material at this day known to the world,’’ Antonio Neri, 1612 800 Journal of the American Ceramic Society—Kurkjian and Prindle Vol. 81, No. 4