Title
Velocity Curves and Quantity of Water Charts
Sub-series contains materials created and used by the Essex Company to calculate velocity, quantity, and height of water under various conditions and situations. Contents of sub-series range in date from 1876-1960, with the majority of the contents being from 1890-1939. Most of the materials are curves, mounted on hardboard, that calculate the amount of water discharged from the types of turbines or wheels in the various mills. Each wheel had a corresponding chart, with many mills utilizing more than one wheel type. Types of wheels used in differing sizes included Hunt, Leffel, McCormick and Hercules. Also present are charts showing discharge from various head gates and weirs.
Collection
Essex Company Collection
Materials are oversized, ranging from 11x17 to 20 x 30. Most are mounted on hardboard.