[Illustration:
_Mathematical Master_ (_after carefully explaining new rule_). "Well,
Tertius, and what is four per cent. on £5?"
_Tertius._ "Ten shillings."
_Mathematical Master._ "No, no."
_Tertius._ "Five shillings."
_Mathematical Master._ "No!"
_Tertius._ "Half-a-crown."
_Mathematical Master._ "Now, Tertius, it's no use guessing; just think.
I'll give you half-a-minute to pull yourself together." (_After interval
of half-a-minute_) "Well?"
_Tertius_ (_with confidence_). "Please, Sir, there isn't one."]
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