Harvey Fletcher worked with Robert Millikan on the development of the oil drop experiment. His recollection describes replacing rapidly evaporating droplets with oil and observing individual charged drops for longer times. The measurement combines motion under gravity and Stokes drag law with the effect of an applied electric field. Estimating the drop's size and comparing its motion before and after charge changes makes small increments of electric charge measurable. His account therefore connects the experimental choice of droplet material with the precision of the charge measurement.[ref]
My Work with Millikan on the Oil-Drop Experiment by Harvey Fletcher. Authored recollection, pp. 44–47; editorial sidebar excluded
Physics and acoustics.[ref]
https://archives.lib.byu.edu/agents/people/3946. Independent professional profile
Portrait of Harvey Fletcher
. American Institute of Physics (AIP), Emilio Segrè Visual Archives. Attribution permission: unrestricted reuse, derivatives and commercial use permitted with attribution to American Institute of Physics (AIP), via Wikimedia Commons. Source. Articles by others on the same topic
Harvey Fletcher (1884-1981) was a prominent American physicist known for his significant contributions to the fields of acoustics and speech science. He is best recognized for his work on the development of the theory of sound and its perception, particularly in relation to human hearing and the design of hearing aids. Fletcher is also notable for his research on the measurement of sound levels, as well as for the development of audiometric techniques and standardized testing procedures for hearing assessment.