A further reading tells us that “the humidifier is ample capacity,” which statement suggests the possibility that not all humidifiers are large enough. But look what advertisement (_D_) informs us: “No heat lost by being radiated through casing into cellar.” This is certainly an interesting point to consider. And reading on we learn: “Long fire-travel in radiator insures a cool smoke-pipe and there is no fuel wasted.” This is surely a matter of design that ought to be observed in good furnaces. Still another fact is brought to light by “Fire-pot—one piece, heavy-ribbed for purposes of increasing its radiating surface and to give it greater power of resistance against expansive force of the fire.” But here is something none of the other advertisements have told us: “Steel radiators are preferable for the use of hard coal; cast-iron radiators for soft or hard coal or wood.” Also: “Radiators can be turned in either direction, thereby permitting smoke-pipe to be connected with chimney from the most advantageous point.” Finally, when we read in advertisement (_E_) the following, “Grate-bars are quickly removed and replaced. No bolts used,” we wonder whether other furnaces use bolts, and whether there is a real objection to them. Taking the information given in these advertisements, we can now make the following list of points to be considered in selecting any one make: 1. Is the grate so designed that clinkers will not form? 2. Are the grate-bars easily removable? 3. Is the ash-pit large and roomy and is the door amply large? 4. Is the radiator in one piece or so well fastened that it is gas-tight? 5. Is the radiator steel or a high grade of cast-iron? 6. Is the inner casing so well insulated that it prevents premature heating of the descending air-currents? 7. What protection is there to prevent the chance passage of smoke into the warm air-chamber? 8. Is the outer casing properly insulated to prevent the waste of heat into the cellar? 9. Is the humidifier of ample capacity? 10. How is the fire-pot designed to increase the efficiency of its radiating surface and how is it strengthened against the expansive force of the fire? 11. Is there a long enough passage for fire-travel, so that no waste of heat is lost up the chimney? 12. Is the radiator flexible enough to permit of the connection of the smoke-pipe from the most advantageous point?