I need to know which oil was used by Robert A. Millikan in his oil drop experiment, i.e.name of oil or chemical formula of the oil molecule.
[Physics] Which oil was used by Robert A. Millikan in his oil drop experiment
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Best Answer
The name, as far as I can find, is "highest grade of clock-oil" as mentioned in his 1913 paper (page 111, last line). The density of this oil at $23\, {}^\circ \mathrm C$ is $0.9199$, but the units aren't mentioned.
EDIT: I went to look up an earlier work (1911) and found two other oils of interest that were used, namely "cleaned gas engine oil" of density $0.9041$ and the more volatile mineral oil (machine oil) of density $0.8960$, both measured at $25\, {}^\circ \mathrm C$. I believe these are the oils the Wikipedia entry alluded to.