What is "baroscope"

Baroscope \Bar"o*scope\ (b[a^]r"[-o]*sk[=o]p), n. [Gr. ba`ros weight + -scope: cf. F. baroscope.] Any instrument showing the changes in the weight of the atmosphere; also, less appropriately, any instrument that indicates or foreshadows changes of the weather, as a deep vial of liquid holding in suspension some substance which rises and falls with atmospheric changes.

n. barometer