Kymograph

A kymograph (which means 'wave writer') is a device that gives a graphical representation of spatial position over time in which a spatial axis represents time. It basically consists of a revolving drum wrapped with a sheet of paper on which a stylus moves back and forth recording perceived changes of phenomena such as motion or pressure.

It was invented by German physiologist Carl Ludwig in the 1840s, and found several usages in the field of medicine. Its primary use was to measure phenomena such as changes in muscular contractions or physiological processes. It was also used in the early days of intrusive blood pressure monitoring.

Kymographs were also used to measure atmosphereic pressure and the functioning of steam engines.

External site:
 * Photo and Description of a 1903 Kymograph

Kimograf