Noun
(historical) An early form of Gantt chart.
An image created by the harmonograph.
Source: en.wiktionary.orgAPM Publishing Limited, 2002 ISBN 1-903494-01-X p.xxii who is famous for his use of the Gantt chart as a project management tool (alternatively Harmonogram first proposed by Karol Adamiecki Edward R. Marsh (1975). Source: Internet