The Measuring Devices hierarchy contains terms for instruments or containers designed and often calibrated to measure, for example, extent, quantity, capacity, mass, or position in terms of a standard unit or fixed amount. Terms for devices for indicating or recording the data obtained are also included. Included are terms for instruments for observing and measuring light, heat, the basic universal forces, weather, as well as timekeeping devices and scales. Relation to other hierarchies: Terms for the Components of measuring devices (e.g., "balance springs," "gnomons") are found in the Components hierarchy, with the node having a non-preferred partitive relationship here. Instruments that may be used to measure or record, but whose primary purpose is for drafting (e.g., "beam compasses") or for fabricating (e.g., "dividing engines") are in the Tools and Equipment hierarchy. Ungraduated vessels that may hold liquids or solids (e.g., "pitchers") and thus be used for comparing amounts, but whose primary purpose is to contain and not to measure, are found in the Containers hierarchy.
