Arther Bolland introduced the Oracle in a wooden case during the second world war. An iron clad version was manufactured in 1952  suitable for outdoor use.

The mechanism was quite a simple affair consisting of  two balanced brass arms, one containing the word YES on one end and the other the word NO.  When a coin is placed in the slot it strikes a v shaped metal strip and either drops into the left or right hand slot at the end of one of the brass arms, which then tips to slide the answer down into the window.

When attached to the wall this machine has to be mounted perfectly horizontal otherwise you get a much higher percentage of yes or no depending on either a left or right hand slope.

Other fortune tellers by Bollands were the Predicta, Heaven and Hell and the Gypsy.  All were made in the iron clad version. According to Bollands they were suitable for Piers, Amusement Parks, Railway stations, Holiday Camps, Tea Gardens and Bus Stations!