1889 adding machine

This adding machine was given to me by my great-grandfather when I was ten years old. He said he had used it to tally cotton weights. I think he gave it to me because I listened to his stories. The machine has two wheels that are moved by using a stylus. The larger wheel has numbers from one to 99. The smaller wheel goes to 49, so you can add to 4999. I has a tag that says A. H. Barber C S Co. Chicago, Ill. Around the small wheel it says Pat'd Nov. 5th 12th 1889. The number 10 is stamped on the back. It has a stylus. I think it is the original, but I'm not sure. One of the rubber legs on the back is missing. I have kept it oiled with machine oil so it still works.
I have tried to find someone to appraise it, but those I have asked know nothing about it.