Remove the hardened spring-plate from the water or oil and prepare to temper it. To do this make a brisk fire with plenty of live coals; smear the hardened plate with tallow, and hold it over the coals, but do not urge the draught of the fire with the bellows while so doing; let the fire heat the steel very gradually and evenly. If the plate is a long one, move it slowly over the fire so as to receive the heat equally. In a few moments the tallow will melt, then take fire, and blaze for some time; while the blaze continues incline the plate, or carefully incline or elevate either extremity, so that the blaze will circulate from end to end and completely envelop it. When the flame has died out, smear again with tallow and blaze it off as before. If the spring is to undergo hard work the plates may be blazed off a third time. Then let them cool themselves off upon a corner of the forge; though they are often cooled by immersion in water, still it is not so safe as letting them cool by themselves. After tempering the spring-plates are “set,” which consists in any warps or bumps received in the foregoing processes being put straight by blows from a hammer. Care should be taken to have the plates slightly warm while doing this to avoid fracturing or breaking the plates. The plates are now filed on all parts exposed to view, _i.e._ the edges and points of the middle plates, the top and edges of the back plate, and the top and edges of the shortest plate. They are then put together and a rivet put through the spring at the point of greatest thickness, and this holds, with the help of the studs before mentioned, the plates together. It is evident from the above description of a common mode of making springs, that the operation is not quite so perfect as it might be. The plates, instead of being merely tapered at the ends, ought to be done so from the rivet to the points. And another thing, it would surely make a better job of it if the plates were to bear their whole width one on the other; in the middled plates they only get a bearing on the edges, and the rain and dust will inevitably work into the hollows in the plates, and it will soon form a magazine of rust, and we all know what an affinity exists between iron and oxygen and the result of it; as far as carriage springs are concerned, it very soon destroys their elasticity and renders them useless and dangerous. To prevent oxidation some makers paint the inner faces of the springs, and this is in a measure successful, but the play of the spring-plates one upon the other is sure to rub off some portions of the paint, and we are just as badly off as ever. A far better plan would be to cleanse the surfaces by means of acid, and then tin them all over, and this would not be very expensive, and certainly protect the plates of the spring longer than anything else.