This section is from the book "Secrets Of The Great Mysteries", by Oudini. Also available from Amazon: Secrets Of The Great Mysteries.
The performer must have a duplicate key for the lock which is used. This is fastened to a string, as shown in Fig. 3, and the other end of the string tied inside of the clothing, so that it cannot be lost during the act. The performer now steps into the bag, Fig. 2, and is locked securely as in Fig. 1, after which the cabinet is placed around him. He now takes out his key, sees that it is securely tied to one end of the string, leaving the other end still tied to some portion of his clothing, as it would be a serious matter to lose the key, and the escape would become impossible, and pushes the key out through the small opening between the bag and the flap, as shown in Figs. 1 and 3. After the key is pushed out he leans over so that the key comes on the upper side and its weight holds it against the canvas. Now, by taking a fold of the canvas in his hand, he can grasp the key and fish for the lock. Having found the key hole he can insert and turn the key and remove the lock, then pull out the strap "C" from the hasps and open the flap. He now steps out. The bag is now to be closed and locked exactly as it was with the performer inside, the keys concealed, the assistant is signalled, and the cabinet removed, showing the audience the bag and performer just as they saw them at the beginning of the act.
Fig. 1. Mail Bag.
The author has also performed this act handcuffed and shackled before being placed in the bag, escaping in the same time as with the bag alone. He has worn six pair of handcuffs of different makes, two chains, and three makes of leg irons, and several locks.
This is done as follows: While the bag is being locked by the committee he is removing the handcuffs, as described in our chapter on handcuffs, starting as soon as the flap is closed over the top. By the time the bag is locked and the cabinet in place he has the handcuffs off; he then starts the escape from the bag, and after leaving the bag removes his leg irons. All the cuffs, irons, chains, etc., are then placed in the bag, the cuffs open and the bag locked as before.
When well executed this act is very effective, especially with the addition of handcuffs, etc., and always receives much apjplause.