Could this waste be avoided? Certainly. The domestic fire-grate does not possess a single virtue. It should be scrapped forthwith. Coal, as a household fuel, should be prohibited. It should be carbonized. Coke, when burned under the most advantageous conditions, throws off as much, if not more heat, and can be induced to shed practically the whole thereof into the apartment. As the alternative to coke we might rely exclusively on gas, releasing the whole of the carbon residue, approximately 70 per cent. of which results from the distillation of every ton of coal for industry. If we presume an average of 10,000 cubic feet derivable from every ton of coal, then we find that the 100,000,000 tons burned annually in the household grates would give us 1,000,000,000,000--one billion--cubic feet of gas, the whole of which is at present being lost up the chimney. From this enormous volume of gas, each 10,000 cubic feet of which contains on the average two gallons of benzol capable of reclamation, we could, if we were sufficiently energetic and enterprising, obtain 200,000,000 gallons of benzol--twice the petrol imports for the year 1913. In comparison with what liquid fuel we could derive from our coal the actual 41,000,000 gallons secured to-day certainly appears to be trifling. Our methods of burning coal in the home, which is appallingly wasteful, is equalled by the general folly investing our system of gas supply, which is equally improvident, simply because we prefer to cling to the obsolete order of things rather than to march with progress. Years ago, to protect gas-consumers, a standard of value was established. The gas had to comply with a certain candle-power standard. The unit thus was one of luminosity. Such a system was satisfactory in days gone by, when the practice was to use a burner and open flame of the fish-tail or bat’s-wing shape. Then some method of standardizing gas according to its luminous intensity undoubtedly was imperative. But judgment of gas by its luminosity with an open burner is effete. It became relegated to the limbo of things that were by the discovery of Welsbach, which effected a complete and wonderful revolution in gas illumination. His invention supplied the means of securing brilliant illumination with heat. This may sound paradoxical, but is readily explained. The particles of the nitrates of the rare earths, thoria and ceria, which enter into the composition of the incandescent gas mantle, will not emit light until they have been raised to a high degree of incandescence. This can only be achieved by using the mantle in conjunction with an atmospheric, or Bunsen, burner.