In respect to the means of giving a fire-proof quality to a house already built, Mr. Loudon remarks:--“All the interstices between the floors, in the partitions, and in the roof, where there was a ceiling formed to the rafters, might perhaps be filled in with earthy matter in a state of powder. This powder might be clay or loam mixed with a small proportion of Roman cement; it might be injected into the vacuities, through small orifices, by some description of forcing-pump or bellows, which, while it forced in the powder, would permit the escape of the air; and, while this operation was going forward steam might be injected at the same time, so as to mix with the mortar and be condensed by it; by which means the whole mass would be solidified with a minimum of moisture. In short, in rendering houses fire-proof, the next important object to using fire-proof materials, is that of having all the walls and partitions, and even the steps of wooden staircases, filled in-with such materials as will render them in effect solid. On examining into the causes of the rapidity of the spread of the flames in London houses when on fire, it will almost invariably be found, that whatever may have occasioned the fire to break out, the rapidity of its progress has been in proportion to the greater or less extent of the lath and plaster partitions, the hollow wooden floors, and the wooden staircases. Were the occupiers of houses sufficiently aware of the danger from lath and plaster partitions, especially when inclosing staircases, they would never occupy such houses, or, if they did, they would not give such rents for them, as they would for houses with brick-nogging partitions. It appears to us to be the duty either of the general or local government or police to see that no houses whatever are built without stone or iron staircases; and that no partitions and floors are made hollow; or, if they are, that the materials should be iron and tiles, or slates, or stones, or cement, or other earthy composition.” CHAPTER XIII. MISCELLANEOUS PROCESSES. The various processes and details which have occupied the preceding chapters, are for the most part necessary to the production of every house. There are, however, many articles of iron and a few of brass employed in the interior and exterior fittings; but were we to enter into details respecting the iron manufacture, in order to show the modes of producing these articles, it would be difficult to confine this volume within reasonable limits. A few miscellaneous processes and details may, however, be collected in this chapter. The principal metallic articles employed in the construction or permanent fittings of a house, are nails and screws; hinges; locks and keys; stoves and grates; bells, and the mechanism for hanging them; iron railings and bars; brass handles, plates, and other decorations; latches and fastenings, &c. Nails.