Abstract: A highly efficient discharge lamp has a color rendering index of about 85, a lumens per watt rating of about than 90, a correlated color temperature of 3000.degree. K., and a wall loading of about 21 W/cm.sup.2. The lamp has an outer glass envelope and a pair of electrical conductors extending into the interior of the glass envelope; a quartz discharge tube disposed within the outer envelope and including a pair of spaced electrodes which are electrically connected to the electrical conductors for creating an electrical discharge during operation of the lamp, the discharge tube having an arc chamber. An arc generating and sustaining medium is provided within the arc chamber and includes the halides of sodium, scandium, lithium, dysprosium and thallium, a fill gas selected from argon and xenon, and a given quantity of mercury to achieve a desired lamp voltage. In a preferred embodiment of the invention the halides are iodides and are present in the mole ratio of about 24-44:1:9.

Abstract: A highly loaded, double ended arc lamp has a cylindrical arc chamber with a volume of 56 cc and an arc length of 108 mm. The metal halide fill is limited to amount below 0.6 mg/cc and comprises HgI.sub.2 ; NaI/CsI in a 6:1 weight ratio; and scandium metal. The 2000W lamp is employed for stadium lighting.

Abstract: In a mercury vapor arc discharge tube having a pair of electrodes, an emissive material disposed on the electrodes consists essentially of a single phase compound of Ba.sub.x Sr.sub.1-x Y.sub.2 O.sub.4 where x is from about 0.25 to about 0.95.

Abstract: An apparatus and method for accurately dosing and dispensing mercury. The apparatus includes a reservoir containing mercury and a capillary tube extending from the reservoir of mercury to a dispensing needle and having an inlet located intermediate a pair of remotely located ends. The apparatus adjusts the height of a column of the mercury within the capillary tube and measures the height of the mercury column. In one embodiment, a digital vision system comprising a TV camera and monitor digitizes the image of the mercury column within the capillary tube and automatically determines the height of the column. A source of gas is supplied to the inlet in the capillary tube such that a predetrmined amount of mercury is separated from the mercury column and dispensed from the other one of the remotely located ends of the capillary tube.