1. APPARATUS FOR THE ELECTRIC HEATING AND VAPORIZATION OF A LIQUID FOR SPACE-HEATING PURPOSES, SAID APPARATUS INCLUDING A VESSEL CONTAINING SAID LIQUID AND HAVING A VACUUM SPACE, A PNEUMATIC SPACE, A LIQUID-CONTAINING SPACE THEREIN AND A PARTITION SEPARATING SAID VACUUM SPACE FROM SAID PNEUMATIC SPACE, SAID PNEUMATIC SPACE AND LIQUIDCONTAINING SPACE BEING OPEN TO ONE ANOTHER; MEANS CARRIED BY SAID VESSEL TO CONDUCT LIQUID FROM EXTERIORLY OF SAID VESSEL TO SAID LIQUID-CONTAINING SPACE; A PLURALITY OF SPACED APART SLENDER VAPORIZER UNITS CARRIED BY AND WITHIN SAID VESSEL, EACH VAPORIZER UNIT HAVING A HOUSING DEFINING AN ADDITIONAL LIQUID-CONTAINING SPACE OPEN TO THE FIRSTNAMED LIQUID-CONTAINING SPACE AND IN COMMUNICATION WITH EACH OTHER, AN ELECTRIC HEATING ELEMENT-CONTAINING SPACE AND A SPRAYED LIQUID DISCHARGE SPACE, WITH AN OPENING IN SAID HOUSING FROM SAID SPRAYED LIQUID-DISCHARGE SPACE TO SAID VACUUM SPACE, AN ELECTRIC HEATING ELEMENT IMMERSED IN THE LIQUID WITHIN EACH OF SAID ELECTRIC HEATING ELEMENTCONTAINING SPACE AND WITHIN THE ADDITIONAL LIQUID CONTAINING SPACES AND BELOW SAID SPRAYED LIQUID DISCHARGE SPACE, AND CARRIED BY SAID VESSEL; MEANS FOR CREATING A VACUUM IN SAID VACUUM SPACE, CARRIED BY SAID VESSEL; MEANS FOR SPRAYING LIQUID UPON EACH OF SAID ELECTRIC HEATING ELEMENTS, CARRIED BY SAID VESSEL AND OPENING TO THE ELECTRIC ELEMENTS-CONTAINING SPACES; MEANS CARRIED BY SAID VESSEL FOR PRESSURIZING THE FIRST-NAMED LIQUID AND OPENING TO SAID PNEUMATIC SPACE; AND MEANS CARRIED BY SAID VESSEL FOR THE DISCHARGE OF HOT VAPOR FROM SAID VACUUM SPACE, THE LIQUIDCONTAINING SPACE IN EACH OF SAID HOUSING HAVING A LIQUID CAPACITY CONSIDERABLY SMALLER THAN THE LIQUID CAPACITY OF SAID LIQUID-CONTAINING SPACE IN SAID VESSEL, WHEREBY ONLY THE LIQUID WITHIN EACH OF SAID SLENDER HOUSING WILL BE HEATED AND VAPORIZED.