_How to Solder on a Rib._—The inner edges of the rib must be filed bright and smooth, so must that portion where it touches the barrel. Bear in mind that solder will not adhere, unless the surface is made bright. This being done wet a short length of the rib with soldering acid, warm it to a proper heat in the forge fire, and with a common soldering copper, also properly heated, tin or cover the melted surface with solder. With the acid wet another distance, say about three inches, heat and tin this, and so repeat until the entire length of the rib has been gone over. Be careful to have plenty of solder adhering to the inner sides. Also be very careful not to heat the rib so as to blue or blacken it, for when so done no solder will adhere, and the surface so made must be brightened up again before going any further with the tinning. The next thing to be done is to draw-file the gun barrel where the rib is to be fastened on, and care must be taken to have the surface bright and clean, or the solder will not adhere. Place the breech end of the barrel in a clean charcoal fire and carefully warm it sufficiently, wet with the acid, and with the soldering copper tin over where it was draw-filed. Two tests can be applied to learn if the barrel be sufficiently heated. One is that when a drop of acid is put on it will “sizzle” or boil; the other test is to hold it close to the cheek and if a warm “glow” of heat is felt from it, it is hot enough. When the surface is tinned, and before the barrel is cold enough so as to harden the solder, wipe off the surplus with a rag, and if the rag be slightly oiled, it will operate all the better. The solder used is common soft solder such as used by tinsmiths. Repeat the process of heating and tinning three or four inches at a time, until the entire length of the barrel has been gone over. Then, after it is cool, place the rib in position, confining it in place with binding wire, putting it round both rib and barrel, twisting the ends pretty firmly together. Fasten the rib in this way, at intervals of about six inches, being careful that the rib is held evenly, closely and firmly to the barrel.