Three videos are presented here, with sound, in slow motion:
- View of the mechanism from under the machine.
- View from above the machine, while introducing a number into Register I.
- View of the operation on the carriage, during the add-and-carry mechanism.
1) The first video shows the rotation of the stepped drums for one cycle of the motor, from under the machine.
2) The second video shows the rotation of the stepped drums, from above the machine, while adding three adjacent digits to the Product Register.
3) The third video shows the sequence of an addition with its carry mechanism.
What is it all about?
We must add the number 789 to the number 333. As it was previously described, in the first part of the cycle, digits are added up, without concern to the carry. So, adding 9 to 3 give 2, adding 8 to 3 give 1, and adding 7 to 3 give 0. At the end of this step, we see that the displayed number is 012. As each figure has turned, during this step, from 9 to 0, the pawls engaging the carry mechanism are set for all three digits. Therefore, each digit, at left of the one which has the pawl pushed forward, is incremented by one unit. So, from right to left, 2 remains 2, 1 becomes 2, 0 becomes 1, and a fourth digit 0 becomes 1. Finally, the total is 1122.