This section is from the book "Secrets Of The Great Mysteries", by Oudini. Also available from Amazon: Secrets Of The Great Mysteries.
An iron boiler, such as is used by hotels, is seen upon the stage. This is examined by the committee to see that there is no defect. The performer is seen to enter the boiler. Tire cover is then placed on and two rods are run through the boiler and the cover, at right angles to each other, and padlocks placed through holes in the ends of the rods, (four in all), to prevent the cover from being removed from the inside. The cabinet is then placed around the boiler, and after 10 or 15 minutes the performer appears, free, before the audience. Again the committee examines the boiler, which still has the cover in place and locked on. No one can discover how the escape was made or can see any change in the apparatus.
With the aid of the accompanying cuts the process will be shown. Fig. 3 shows the appearance of boiler with cover in place. The body of the boiler, "A," is made of heavy galvanized iron, strongly riveted together. The cover is perfectly solid except for the air holes, as shown. The rods "D" are metal, about five-eighths inch thick. These rods, while having the appearance of hard steel, are really made of softer steel, which can be bent or cut with a hack saw. Fig. 4 is a section showing how the cover fits inside the end of the boiler, and is held in place with the rods.
 
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