It is sincerely to be hoped that the clause in the last Metropolitan Building Act, restricting the size of warehouses, may be more successful than its predecessor, for it is not only property that is at stake, but human life. In many of these "Manchester warehouses," there are fifty or one hundred and upwards of warehousemen and servants sleeping in the upper floors, whose escape, in case of fire, would be very doubtful, to say the least of it.[E] Covering timber with sheet-iron is very often resorted to as a protection against fire. I have never found it succeed; but Dr. Faraday, Professor Brande, Dr. D. B. Reid, and Mr. W. Tite, M.P., are of opinion that it may be useful against a sudden burst of flame, but that it is worse than useless against a continued heat. In wadding manufactories the drying-rooms were frequently lined with iron-plates, and when a fire arose there, the part covered with iron was generally found more damaged than the rest; the heat got through the sheet-iron, and burnt the materials behind it, and there was no means of touching them with water until the iron was torn down; sheet iron should not, therefore, be used for protecting wood. Even cast iron, one inch thick, laid on tiles and cement three inches thick, has allowed fire to pass through both, to the boarding and joisting below, merely from the fire in an open fire-place being taken off and laid on the hearth. This arises from iron being so good a conductor that, when heat is applied to it, it becomes in a very short time nearly as hot on the one side as the other. If the smoke escapes up a chimney, or in any other way, there may be a serious amount of fire before it is noticed. In a fire at the Bank of England, the hearth on which the stove was placed was cast iron an inch thick, with two-and-a-half inches of concrete underneath it; but the timber below that was fired. With regard to the subject of fire-proof dwelling-houses of average size, I consider that such houses when built of brick or stone, with party-walls carried through the roof; the partitions of brick, the stairs of slate or stone, the joists of wrought iron filled in with concrete, and the whole well plastered, are practically fire-proof because, as stated at the opening of this chapter, there is no probability that the furniture and flooring in any one room would make fire enough to communicate to another. The safest manner of heating such houses is with open fire-places, the hearths not being laid upon timber. Stone staircases, when much heated, will fracture from cold water coming suddenly in contact with them; but in a dwelling-house built as described above, there is very little chance of such a circumstance endangering human life, even with wooden steps carried upon brick walls, and rendered incombustible by a ceiling of an inch and a quarter of good hair mortar and well pugged, all the purposes of safety to human life would be attained.