Here is a story told to me by one of my friends who was at that time a young professor of physics in Odessa. His name was Igor Tamm (Nobel Prize Laureate in Physics, 1958). Once when he arrived in a neighbouring village, at the period when Odessa was occupied by the Reds, and was negotiating with a villager as to how many chickens he could get for half a dozen silver spoons, the village was captured by one of the Makhno bands, who were roaming the country, harassing the Reds. Seeing his city clothes (or what was left of them), the capturers brought him to the Ataman, a bearded fellow in a tall black fur hat with machine-gun cartridge ribbons crossed on his broad chest and a couple of hand grenades hanging on the belt.

    'You son-of-a-bitch, you Communistic agitator, undermining our mother Ukraine! The punishment is death'.

    'But no', answered Tamm. 'I am a professor at the University of Odessa and have come here only to get some food.'

    'Rubbish!', retorted the leader. 'What kind of professor are you?'

    'I teach mathematics'.

    'Mathematics?', said the Ataman. 'All right! Then give me an estimate of the error one makes by cutting off Maclaurin's series at the nth term. Do this and you will go free. Fail and you will be shot!'

    Tamm could not believe his ears, since this problem belongs to a rather special branch of higher mathematics. With a shaking hand, and under the muzzle of the gun, he managed to work out the solution and handed it to the Ataman.

    'Correct!', said the Ataman. 'Now I see that you really are a professor. Go home!'

    Who was this man? No one will ever know. If he was not killed later on, he may well be lecturing now on higher mathematics in some Ukrainian university.

W. Gratzer, Eurekas and euphorias: the Oxford book of scientific anecdotes. Oxford University Press 2002, p. 36.