To live among friends is the primary essential of happiness. - William Thomson, 1st Baron Kelvin

Quaternions came from Hamilton after his really good work had been done, and though beautifully ingenious, have been an unmixed evil to those who have touched them in any way.

I need scarcely say that the beginning and maintenance of life on earth is absolutely and infinitely beyond the range of sound speculation in dynamical science.

Every boy... should be able by the age of 12 to write his own language with accuracy and some elegance; he should have a reading knowledge of French, and be able to translate Latin and easy Greek authors, and have some acquaintance with German. Having learned thus the meaning of words... a boy should study Logic, so as to be able to apply his words sensibly.