. Electric railway review . ne rerlng q itloni The thermit com] ml Is compi oi aluminum and iron oxide, both in •.,,m. the ignition powder is con aluminum ami barium oh- in much iiu. i i,.i m When Hi. match II lo til, slun i iy quick] produced I • SI ELECTRIC RAILWAY REVIEW Vol. XVIl, No. 3. tense that it causes the iron oxide to release its oxy-gen, which in turn is seized by the aluminum andalmost Instantly the entire contents of the crucible are aboiling and seething mass. By this reaction the pure steelis liberated and settles immediately to the bottom of thecrucible. This wonderful
. Electric railway review . ne rerlng q itloni The thermit com] ml Is compi oi aluminum and iron oxide, both in •.,,m. the ignition powder is con aluminum ami barium oh- in much iiu. i i,.i m When Hi. match II lo til, slun i iy quick] produced I • SI ELECTRIC RAILWAY REVIEW Vol. XVIl, No. 3. tense that it causes the iron oxide to release its oxy-gen, which in turn is seized by the aluminum andalmost Instantly the entire contents of the crucible are aboiling and seething mass. By this reaction the pure steelis liberated and settles immediately to the bottom of thecrucible. This wonderful chemical action is concluded with-in 30 seconds, the crucible is tapped by striking the tap-ping pin with a special iron spade, and the incandescentsteel runs smoothly into the mold, the aluminum oxide orcorundum slag following. In five minutes the mold can beremoval tor Hie passage of cars. Some Improvements. To go back to the beginning of the operations, our at-tempts to make molds of half proportions of clay and sand. Thermit Rail Welding—Welded Compromise Joint. resulted unsatisfactorily in that they shrunk and checkedbadly in baking and required a great amount of careful lutingto fill all irregularities at the joints. Also the clay wasbaked like a brick from the great heat of the welded jointand was quite hard to remove, adding somewhat to the ex-pense. An old foundryman suggested to our foreman that heshould try a mixture of clean, sharp sand with 10 per centof coarse rye flour, moistening the mixture sufficiently toretain its form when pressed in the hand. This mixture cameaway from the model without adhering, baked withoutshrinking a particle, and was hard enough to stand ordi-nary handling. I believe we were the first users of thermitto employ this mixture that has now become general. Forbaking the molds we have found that a moderate heat ofabout the temperature required in baking bread provedmost satisfactory, as a higher temperature burned the ryeflour and dest
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