4 o'clock
When you walk abroad you stride along muttering , waving your arms and bumping into people ; you forget to eat ; your friends fall away from you . Let me advise parents who are thinking of a career for their sons never to make inventors of them . It 's a dog 's life . Far better to put them to something with regular hours , say from 10.30 to 4 o'clock , which leaves them with the evenings free . William would n't divulge what his invention was , because , he said , he was afraid of the idea getting about before he took out the patent . He merely told us it was a device which no man living could do without . But he went so far as to show us the inner workings of his discovery -LRB- hereinafter referred to as It -RRB- , which , not knowing what they were for , rather mystified us .