An acetylene blowpipe is described in the "Mechan-cal Engineer," London, due to one Fouche. This tool consists of a flame of acetylene gas blown in the usual way with a blowpipe, but with oxygen gas, so that the resulting temperature is enormous because the flame contains no inert dilutent nitrogen. Such a tool should be of very great service in the workshop, and also in the field. By its aid a broken locomotive frame could be welded. It should be useful at sea for repair work, and in many ways it will prove of service. The apparatus is simple and consists of a supply of the two gases, a suitable water seal, and the blowpipe. A rod of pure iron serves as a soldering-stick or making up supply. It is said that some of the carbon from the flame combines with this pure iron and converts it into mild steel. The superiority of the acetylene-oxygen flame over the oxhydrogen flame lies in the fact that for each cubic metre of oxygen there are theoretically required two cubic metres of hydrogen, but the flame produced is so oxidizing that practically it is necessary to employ a doubie quantity of hydrogen. Theoretically, two and one-half volumes of oxygen are required for each volume of acetylene, but in practice only 1.7 volumes of oxygen are used. The flame of acetylene is much less diffused, and the heat is therefore better applied, and less is wasted in heating up surrounding metal needlessly. Thus, for the two mixtures, the heat per cubic metre will be: for acetylene 5338, for hydrogen 2473 calories. These and other considerations are said to account for the fact that ten times as much hydrogen as acetylene is required for a given piece of work, or one and a half times as much oxygen.
Sulphite of aluminum is a compound that can successfully be used in making wood fireproof. When strongly heated this compound leaves an infusible and non-conducting residue to cover and protect the cellular structure throughout the wood. It absolutely prevents the propagation not only of flame, but even of a glow because of its non-conducting and unalterable character. Sulphate of aluminum in concentrated solution is far more efficient than an alum solution; in fact, it would seem as if the alkaline sulphate of the alum simply detracted from the power of the alu_ minum sulphate in the matter of making wood fire re. sistant.