The next letter contained sketches of the machine, and a third told the sad story of the machine's being destroyed by fire. No records exist of the events that led Schickard to build a calculator, although he was familiar with Napier's logarithms and his bones.

It's hard to tell how successful his machine would have been because he didn't rebuild it. But he would have had to overcome the problems that beset the inventors of the visionary period such as lack of precision work and over-rotation of the wheels.