IV. Every plant must also be effective by day, and must not, when not illuminated, stick up into the sky like a forgotten bit of scaffolding. V. The contracting firm must give a year’s guarantee that all faults and disturbances not arising from violence or unsuitable treatment will be repaired at once. This does not apply to bulbs which become defective. But it does apply to light tubes which on account of porous spots, permit an escape of gas (recognizable when the tubes change color as soon as the currents turned on). VI. The permission of the building police (Advertising Section) must be procured by the com- missioned party, the dient paying the costs. The contracting firm is responsible for the proper fulfilment of the police conditions. The costs of a plant are offen out of all proportion to its effectiveness. This is especially the case with advertising on gables. Letters of light, usually employed for the name of the firm, are least of all suited to the purpose. Extremely effective and economical are enamel letters irradiated with light, their stems being bent concave and irradiated. This type of illuminative advertising has only prevailed in Germany in a few stray instances. Yet it oflfers overwhelming advantages in all four points: initial inexpensiveness, economical use of current, cheap upkeepand effectiveness. Leuchtfontäne auf der Kolonial- Ausstellung in Paris Jlluminated Fountain at the Colonial Exhibition, Paris