17th Century pocket calculator for sale (from our “You Can’t Make This Stuff Up” file)

One of four surviving 17th Century “pocket” calculating machines is scheduled to be auctioned at Christie’s in London this coming October.

Invented in the late 1600s by Rene Grillet, a French inventor and watchmaker, the paper and wood box measures about five and half inches by nearly 13 inches, and features 24 separate dials embedded in the box lid. According to the Reuters report, the calculator was capable of performing addition, subtraction, multiplication and division using the so-called “Napier’s bones” logarithm.

However, there’s little chance that the calculating machine would be confused with today’s smart mobile devices or even the advanced scientific calculators of the 1970s and 1980s, since the pocket calculator required users to “carry the 10s” when computing multiple numbers.

Christie’s has estimated that the antique pocket calculator will sell for between 70,000 and 100,000 pounds (about $108,000 to $155,000 U.S.) at auction.