This section is from the book "Secrets Of The Great Mysteries", by Oudini. Also available from Amazon: Secrets Of The Great Mysteries.
The committee from the audience examines the mail bag carefully, inside and out, and find it perfect in every respect, with no opening except at the top; which can be securely fastened, as described and shown in cuts.
The bag is made of leather and canvas, and is almost air tight. The canvas part of the bag is sewed by machine to make it strong; the leather part of the bag is sewed and riveted to the canvas. Fig. 1 shows the style and appearance of the bag to be used. "A" shows canvas part of bag, made large enough for the performer to move around inside. "B" shows the leather .part of the bag, which lifts back to allow entrance to the bag. "C," the leather strap which is to pass through the hasps to fasten the leather top in place. "D" the hasps that the strap passes through. "E" the lock. (If a Corbin lock is used, with the keyhole on the bottom, the escape can be made much quicker and easier.) "F" a small strap which is used to help close the opening on the end so that the performer can not pass his hand out while he is inside. "G" a small opening between the bag and the flap.
Fig. 2 shows appearance of the bag when opened ready for the performer to step in.