_Nails_ are made of iron, either _cut_ by means of a machine into the tapering form which we call _cut brads_, or _wrought_ by means of hammers into the various forms of flooring nails, tacks, &c. _Screws_ are made by forcing a piece of iron wire into a cavity, the surface of which is cut into a spiral or screw-like form; this spiral cuts a similar spiral on the surface of the iron wire, which then becomes a screw; and one end of the wire is hammered or pressed down so as to form the _head_ of the screw. _Hinges_ of the commoner kinds are made by two flat pieces of iron, with a kind of projecting tube at one edge. These tubes are partially cut away, so that the two pieces may lap into each other; and a spindle or pin being passed down through both tubes, acts as an axis, on which both parts of the hinges turn. The more costly hinges require elaborate workmanship in their construction. Locks and Keys. _Locks_ and _Keys_ form a curious part of the hardware manufacture. The lock is made of a great many pieces, put together with screws. One part of it is always a moveable latch or bolt, which is capable, by tolerable force, of being thrust partially out through a hole in the side of the lock; and it is this bolt which, catching in a box or cell fixed to the door-post, secures the door to which the lock is attached. The object of the key is to act as a lever which shall move the bolt; and the great point of attention in the matter is, that no key or lever but one of a particular _size_ and _shape_ shall be able to move the bolt; herein is the security which we feel in a good lock. Wolverhampton and its neighbourhood is the great seat of the lock manufacture. Stoves and Grates. _Stoves_ and _Grates_ are made in a variety of forms. Their employment is obviously greatly dependent on the kind of fuel employed. In the kitchens of the old baronial residences, large logs of wood were thrown upon an immense stone or brick hearth, and there kindled. But when coals became commonly used in London and other great towns of England, about the year 1400, the use of some kind of stove or grate began to be felt, since the fuel was too valuable to be scattered on a wide-spreading hearth. From that time to the present, one continual series of improvements has taken place, having for their objects, to add to the elegance and neatness of a room, to facilitate culinary occupations, and to derive the greatest possible heat from a given quantity of fuel. It is only within a very few years that the principles regulating the last-mentioned circumstance have been at all well understood. Some parts of the metal for a grate or stove are produced by casting, others by forging, and others by rolling or pressing; and they are put together principally by rivets. For further details on this subject we refer to our seventh chapter. Bells.