The WEBB Adder - Francis WEB

Around 1868, a journalist named Charles Henry WEBB invented a small device, made of 2 wheels, that could be used for adding numbers.


Not a great complexity, but the right side allows you to select one number from 0 to 100, and add it to whatever was previously entered. The left wheel counts how many time the right wheel made a complete turn, which means the number of 100s. You can also select a number on the left wheel if you want to add a number greater than 100.

The ADDER was patented on March 10, 1868, and you can see a copy of the patent below:
Patent 75322 from 1868  
Later, he improved on the design and deposited 2 additional patents, in 1889. One of them was under the name of his assignor (Mr SMITH). A copy of these 2 patents is also available below:
Patent 414335 from 1889 under the name of SMITH
Patent 414959 from 1889 under the name of WEBB  

The machine was well constructed and able to add numbers using a wheel with 100 slots.Then the left wheel was automatically counting how many turn the right one did.
With numbers on the left going up to 50, the user could add numbers up to 50 x 100 = 5000 .

Later on, WEBB invented a different type of adding machine, looking very similar to the later golden GEM:


Patent 465120 from 1891 showing the ribbon adder.


Below is a short Video showing how to use the device, and how simple it was.

Below are some statistics about sales of this device on Ebay. I may not have all the numbers, but overall the average price seems to be $275
Highlighted are the smallest price recorded, and the highest.