A quotation by Oliver Heaviside

There is no absolute scale of size in the Universe, for it is boundless towards the great and also boundless towards the small.
Quoted in D'A W Thompson On Growth and Form (Cambridge 1917)

Why should I refuse a good dinner simply because I don't understand the digestive processes involved.
[reply when criticised for his daring use of operators before they could be justified formally.]

Logic can be patient, for it is eternal.
Quoted in D MacHale, Comic Sections (Dublin 1993)

This series is divergent, therefore we may be able to do something with it.

Euclid for children is barbarous.
Quoted in D MacHale, Comic Sections (Dublin 1993)

It is perhaps too much to expect a man to be both the prince of experimentalists and a competent mathematician.
Electromagnetic theory Vol 1 Ch 1