Popular science monthly . Popular Science Monthly A Danger Signal Used to DirectAttention to Overhead Perils THE sign in the accompan\ing illustra-tion has two uses. It consists of ahea\y steel plate, enameled, with a redbackground and white letters, carrying itswarning. When electrical machinery withhigh-pressure currents is being tested, thissign is placed near the apparatus and thewords High Voltage, DANGER the danger is overhead, as whenoverhead wires are being repairedor tested, or when a cranemoving loads which might spilor collapse, the sign is placedwithin the danger z
Popular science monthly . Popular Science Monthly A Danger Signal Used to DirectAttention to Overhead Perils THE sign in the accompan\ing illustra-tion has two uses. It consists of ahea\y steel plate, enameled, with a redbackground and white letters, carrying itswarning. When electrical machinery withhigh-pressure currents is being tested, thissign is placed near the apparatus and thewords High Voltage, DANGER the danger is overhead, as whenoverhead wires are being repairedor tested, or when a cranemoving loads which might spilor collapse, the sign is placedwithin the danger zone anda little sheet-metal flap, fixedto the top of the sign, isdropped down showing anarrow pointing arrow stands outvividly so that anyonepassing would not fail tolook up as directed, fromcuriosity if for no otherreason, before reversing the smallmetal flap the sign may bemade to display simplythe one word A heavy steel plate used todirect attention upward when[the danger is from wires overhead A Locomotive Side-Frame WhichWeighs Nearly Seven Tons ALL passenger and freight engines needin their construction what is knowngenerally as a locomoti\e side-frame. Oneach side of the engine one of these is used;it assists in forming the main frameworkon which the superstructure is built. 8^9 Until about twenty-fi\e years ago, side-frames were usually forged—a slow anddifficult process. Now the cast-steel frameis used. This is made by pouring moltensteel into a sand mold. This, after cool-ing, is removed from the surrounding sandof the mold, and, after cleaning, is carefullyannealed in an annealing furnace to makethe mass of steel homogeneous. With the constant growth in the size ofthe modern locomotives the length andk of the locomotive-frame hasso increased, until now framesire made that twenty yearsago would have been con-sidered impossible. Whenthe one in the illustrationwas made it was the
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1872
