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1 introduced into a wire gauze safe-lampa small cage made of fine wire of platinumof the one-seventieth of an inch in thick-ness, and fixed it by means of a thick wireof platinum about two inches above the wickwhich was lighted. I placed the whole ap-paratus in a large receiver, in which, bymeans of a gas holder, the air could be con-taminated to any extent with coal gas. Assoon as there was a slight admixture of coalgas, the platinum became ignited; the igni-tion continued to increase till the flame ofthe wick was extinguished, and till the wholecylinder became filled with flame ; it thendiminished. When the quantity of coal gaswas increased so as to extinguish the flame ;at the moment of the extinction the cage ofplatinum became white hot, and presenteda most brilliant light. By increasing thequantity of the coal gas still farther, the ig-nition of the platinum became less vivid.When its light was barely sensible, smallquantities of air. were admitted, its heatspeedily increased; and by regulating theadmission of coal gas and air it again becamewhite hot, and soon after lighted the flamein the cylinder, which as usual, by the ad-