That as large a body of oil as possible be kept in actual contact with the arm by washing up as the wheel revolves. That the column of oil may be in no case above the horizontal level of the leakage point while the wheel is at rest. _Welding Steel Axles._ Many axles are now made of Bessemer steel. Generally speaking this is neither more nor less than iron, the pores of which are filled up with carbon or charcoal. The higher the steel the more carbon it contains. If steel be heated it loses a portion of this carbon, and the more it is heated the more it approaches its original state, viz. iron. The welding of steel axles is said to be considerably assisted by the use of iron filings and borax. This is only true in case the steel should be over-heated, and even then only in degree. Borax by itself is a very useful adjunct to this process, and it should have a small quantity of sal-ammoniac added, to assist its fusion or melting. The furnace or fire, which is to be used for the welding process, should be clean and free from new coal, to prevent sulphur getting on the steel. Of course, all coal has more or less sulphur in it; but iron or steel cannot be successfully welded when there is much sulphur in the fire, so it is well to be as careful in this respect as possible. Place the ends of the axles in a clean bright fire, heat to a bright red heat, take them out, lap them over each other, and give them a few smart blows with the sledge. Now well cover them with powdered borax, and again put them into the fire and cover them up with coked coal, give a strong even blast, and carefully watch the appearance of the steel as the heat penetrates it, and see that all parts of the weld are equally well heated. When the heat is raised as high as the steel will safely bear (this knowledge can only be gained by experience, so no rule can be given for ascertaining the degree of heat, as it varies with the quality of the steel) take them out. Have two men ready to use the sledges. Place the axles on the anvil, securing them to prevent their slipping, and while one man places his hammer full on the weld, give the extremity of the lap or weld a smart blow or two, and if it adheres then both sledges can be applied until a true and workmanlike weld is formed. It sometimes happens that when the axles are heated ready for welding and lapped, a light or a heavy blow, instead of uniting the laps, only jars them apart. This is a sure sign that they have been over-heated, and in this case it will be very difficult to form a weld at all. The only way of getting over this difficulty is to heat it to as high a degree as necessary, and put it in a vice and screw it up; the surfaces will adhere in this way when the other means fail.