Wednesday, July 29, 2009

Palmer's Computing Scale

Aaron Palmer patented a slide rule in Boston in 1843. I believe this is the earliest example of an American slide rule.  The "Computing Scale", as he referred to it was available in a number of formats.  In 1846 Palmer apparently sold his patent rights to John E. Fuller. Fuller, in turn, added another circular scale to the original Palmer Computer Scale on the reverse side which would compute the number of days between two dates. Fuller called his scale the "Time Telegraph".
Major variations of Palmer's Computing Scale include:
1.  A 12 inch square hard cardboard device (as shown).
2. A 12 inch square version, as above, with the the Fuller Time Telegraph on the reverse side.
3. Palmer's Pocket Scale, a 10 cm. by 15.5 cm. hardbound book with a smaller version of the 12 inch device attached to the inside rear cover. 48 pp. not including the scale.
4. Key to Palmer's Pocket Scale, the same as 3. above without the slide rule attached to the inside rear cover. This was presumably used as the instruction manual for 1. above. 50pp.
5. Improvement to Palmer's Endless Self-Computing Scale and Key by John E. Fuller. This is like 4. above, but for use with 2. above. 72 pp.
6. Fuller's Computing Telegraph by Aaron Palmer and John E. Fuller, same as 2. above as part of a 22 page book.

I saw one reference to the fact that the use of the word "computing" as associated with the Palmer Scale was the first time that that word was used when referencing a device, as opposed to a person who did that operation.  I cannot confirm this.

Most references to these Palmer devices indicate that it is rare, and the prices they are sold for seem to support this theory.  However, I personally have 12 of them. I did not pay anywhere near the prices I have seen out there.  So, I don't know what to make of this.

Once I bought one of the smaller Palmer Scales on EBay from a fellow in San Francisco. I was in Connecticut at the time and happened to be going to San Francisco about two days after the close of the auction. I asked the fellow if I could come to him in San Francisco to pick it up instead of him mailing it to me in Connecticut. I think I must have spooked him. He refused to agree and insisted that he mail it to me.

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