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, including Clerk Maxwell. – Lord Kelvin, 1892.


Then we must not listen to Homer or to any other poet who is guilty of the folly of saying that two casks

'Lie at the threshold of Zeus, full of lots, one of good, the other of evil lots,' and that he to whom Zeus gives a mixture of the two

'Sometimes meets with evil fortune, at other times with good;'

but that he to whom is given the cup of unmingled ill,

'Him wild hunger drives o'er the beauteous earth.'

– Plato, in "The Republic" source