- Model C
|"Starting SN 35000. Earliest known is SN 36371 and owned by Dorr Felt Tippens,
grandson of the inventor while latest known is SN 48475. Some minor mods were made
starting with SN 40000 including the introduction of celluloid keys to replace the
composition keys employed previously. A lighter key-depression was another improvement.
Quite inexplicibly, the front panel had 4 screws with no apparent use! These screws appear to be layed out exactly as they were for the purpose of holding the two glass dial cover clamps on the A-model. Their purpose and reappearance on this model only is a total mystery.
And for those fascinated by the mystery of oil holes, this model sported some >>29<< of them in the dial cover and keyplate presumably in response to an almost complete lack in the prior model."
Source: The Comptometer Memorial Website