The Palestine pound, like it's counterparts in Egypt and East Africa, was a "decimalized pound", where the pound unit was on par with the British pound, but the fractions were decimal-based. Thus, 100 mils is 1/10th of a pound, or equivalent to a British florin, and 50 mils equal to a shilling. The smaller denominations don't have a simple direct correlation to the British predecimal system; 1 mil was 0.24 of a British penny - so almost, but not quite, a farthing, or just under half of a US cent at the exchange rate of the day.
One mil wouldn't have bought you much back in Palestine in 1927; maybe a small cake of low-grade bread, or a Jaffa orange that was too small or otherwise didn't make the grade for export. Historical trivia: the reason why "jaffa" has now become virtually synonymous with "orange flavour" in British English is because of the quantities of oranges exported from the city of Jaffa (now a suburb of Tel Aviv, in Israel) to Britain during the Mandate period.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis