Full Idea
Some quantities cannot be measured (such as pain), and some things which are not quantities can be measured (such as certain series).
Gist of Idea
Some quantities can't be measured, and some non-quantities are measurable
Source
Bertrand Russell (The Principles of Mathematics [1903], §150)
Book Reference
Russell,Bertrand: 'Principles of Mathematics' [Routledge 1992], p.158