Protective Cover for Glass Electrodes We have discovered a simple way of protecting glass electrodes. A piece of perforated vinyl tubing slipped over the end of the glass electrode protects the electrode from contact with beaker wall, stirrer, or other equipment, and yet permits the use of the electrode for pH measurements. Vinyl tubing, Sis inch i.d., is about the correct size for most standard electrodes, and holes 2-3 mm diameter and spaced 3-4 mm apart seems to work satisfactorily; the tubing should extend 3-5 mm beyond the end of the electrode. This arrangement permits the glass membrane to contact the solution adequately and yet the plastic tubing is strong enough to prevent breakage fmm casual humping. Westminster College New Wilmlngton, Pennsylvania 16142
498 / Journal of ChemicalEducation
H. D. DeWitt
