Hartley's Rotatable Optical Disc Material_Muslin this analog DC microammeter measures

this analog DC microammeter measures 0-100uA at 2uA resolution on a tabletop housing

with a (Br) marking visible on one face for easy identification

this Brownlee-pattern apparatus gives a clean visual proof of the 2:1 stoichiometry of water decomposition

5 inches producing 50-60 dots per second via a vibrating striker

and 26 SWG - sized as the matched replacement set for the PH0730 sonometer

Hartley's Rotatable Optical Disc Material_Muslin this analog DC microammeter measures230mm disc graduated 0 360 degrees in 1 degree steps locks in any position alongside a rotatable lamp house and six magnetic acrylic elements for full ray tracing studies of reflection and refraction.