CHARACTERISTICS OF OPTICAL GLASSES ---------------+--------+--------+------+--------------------------+ | | | | Bracketed | | | | | numbers are | | | dn | | proportions of dn | Glass | n__d_ | ----- | ν +--------+--------+--------+ | | (F-C) | | D-A´ | F-D | G´-F | | | | | ---- | ---- | ---- | | | | | dn | dn | dn | ---------------+--------+--------+------+--------+--------+--------+ Boro-silicate | 1.5069 | .00813 | 62.3 | .00529 | .00569 | .00457 | crown | | | | (.651) | (.701) | (.562) | Zinco-silicate | 1.5170 | .00859 | 60.2 | .00555 | .00605 | .00485 | (hard) crown | | | | (.646) | (.704) | (.565) | Dense baryta | 1.5899 | .00970 | 60.8 | .00621 | .00683 | .00546 | crown | | | | (.640) | (.704) | (.563) | Baryta light | 1.5718 | .01133 | 50.4 | .00706 | .00803 | .00660 | flint | | | | (.623) | (.709) | (.582) | Common light | 1.5710 | .01327 | 43.0 | .00819 | .00943 | .00791 | flint | | | | (.617) | (.710) | (.596) | Common dense | 1.6116 | .01638 | 37.3 | .00995 | .01170 | .00991 | flint | | | | (.607) | (.714) | (.607) | Very dense | 1.6489 | .01919 | 33.8 | .01152 | .01372 | .01180 | flint | | | | (.600) | (.714) | (.615) | Densest flint | 1.7541 | .02743 | 27.5 | .01607 | .01974 | .01730 | | | | | (.585) | (.720) | (.630) | [*]Telescope | 1.5285 | .00866 | 61.0 | .00557 | .00610 | .00493 | crown | | | | (.643) | (.705) | (.570) | [*]Telescope | 1.5286 | .01025 | 51.6 | .00654 | .00723 | .00591 | flint | | | | (.638) | (.705) | (.576) | [* Optical data close approximations only.]