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?