The Webb Adder, or Webb's Adder is one of the first successful adding machines. The first version is from 1868, the second from 1890. The one I have is probably from 1900-1910, as it has no identifying marks anywhere, and was presumably made under license and sold under a different name.
For more information on this machine and other calculators in my collection, go to my site at:
https://www.jaapsch.net/mechcalc/
0:00 Introduction, history
1:08 Addition
2:26 Clearing
3:37 Mechanism
5:30 Outro
