ph-responsive glass electrodes

Claim 1

A PH-RESPONSIVE GLASS ELECTRODE INCLUDING A CONDUCTIVE MEMBRANE OF GLASS WHOSE COMPOSITION IS REPRESENTED BY A THREE-COMPONENT PREFUSION MIXTURE FREE OF THE ALKALINE EARTH METALS, THE FIRST COMPONENT CONSISTING OF ABOUT 69 MOL PER CENT TO ABOUT 63 MOL PER CENT SILICA, A SECOND COMPONENT CONSISTING OF ABOUT 26 MOL PER CENT TO ABOUT 30 MOL PER CENT LITHIA, AND THE BALANCE A THIRD COMPONENT CONSISTING ESSENTIALLY OF AT LEAST AN OXIDE SELECTED FROMA FIRST GROUP CONSISTING OF TIO2, MNO2, MN2O3 AND THE RARE EARTH METAL OXIDES INCLUDING LA2O3 AND PR2O3, AND OF AT LEAST ONE ADDED ALKALI METAL OXIDE SELECTED FROM A SECOND GROUP CONSISTING OF THE FOLLOWING: CS2O, RB2O, K2O AND NA2O, THE SUM OF THE MOL PER CENT OF AT LEAST ONE OF SAID OXIDES OF SAID FIRST GROUP AND AT LEAST ONE OF SAID ALKALI METAL OXIDES OF SAID SECOND GROUP BEING NOT LESS THAN ABOUT 3 NOR MORE THAN ABOUT 10, THE PERMISSIBLE MOL PER CENT OF THE OXIDES FROM SAID FIRST GROUP RANGING FROM 2 TO ABOUT 5, THERE BEING PRESENT IN EACH MIXTURE INCLUDING NA2O A GREATER MOL PER CENT OF AT LEAST ONE OF THE ALKALI METAL OXIDES CS20 AND RB2O THAN THE MOL PER CENT OF NA2O, AND THERE BEING PRESENT IN EACH MIXTURE INCLUDING K2O A MOL PER CENT OF AT LEAST OF NOT LESS THAN ABOUT METAL OXIDES CS2O AND RB2O OF NOT LESS THAN ABOUT TWO-THIRDS THAT OF THE K20, THE MOL PER CENT OF ALKALI METAL OXIDE RANGING FROM 0 TO ABOUT 5.