_Joining Barrels Together._—After the barrels are fitted together so that they are parallel, touching each other their entire length and equally in a vertical line, the next thing in order is to fit the top and bottom ribs. Fit the lower thimble or pipe through which the cross-bolt goes and cut the under rib to fit both above and below it, as this thimble is soldered direct to the barrels, not to the rib. Mark along the sides of the ribs with a sharp scriber, so as to leave a distinct line on the barrels to indicate their location. File bright and smooth the parts of the pipe and ribs where they are to be joined to the barrels and tin with good soft solder. Also tin the barrels where they are to be joined, and where the ribs come in contact. This is easily done by using a clear charcoal fire and heating the barrels and ribs quite slowly. Use muriate of zinc for flux, and apply the solder with a common soldering copper. If the copper be quite heavy and well heated the ribs can be tinned from the heat of the copper, as there is no need of putting these parts in the fire. If the barrels be properly heated and the solder beaten out thin on an anvil, it may be rubbed on the barrels without the aid of the copper. When it melts and flows, wipe off the surplus with a woolen rag which has been slightly moistened with oil. When the barrels and other parts are nicely tinned, let them cool, and then fasten them in place in the manner they are to remain with binding-wire. Put a rod of iron through the lower thimble, and also through the upper thimbles, if they are to be fastened at this time. The reason of putting in this rod is twofold: it serves to keep the thimbles straight with the barrels, so as to properly receive the ramrod, and at the same time tends to hold the under rib firmly in place. Before fastening the parts with binding wire, fill the space between the top rib and barrels with small pieces of solder, or what is better, a small rod of solder like a wire, but not large enough to interfere with the rib fitting close to the barrels. _Soldering Barrels Together._—Now begin to carefully heat the work, commencing at the breech, and when sufficiently hot, don’t heat too fast nor too hot, apply solder, using the muriate of zinc as a flux, to the joinings of the ribs and barrels. If the solder be hammered quite thin it will be readily melted by the heat of the barrels, and will be “sucked in” until the space between the different pieces is completely filled. Proceed carefully in this way until the entire length of the barrels is gone over. Turn the work often in the fire, so that all portions are evenly heated. At the muzzle fit and insert a small piece to fill the interstice between the barrels and the top rib.