AT SUMMER’S DOG DAYS I travel to Cobalt in Northern Ontario. Created overnight by the discover y of rich silver deposits in 1903, the town set off a mining boom; bet ween 1905 and 1914 alone more people than Canada’s entire population at the time traveled there by train. The area became fabulously rich, but when the silver ore dwindled it all ended as quick ly as it started. Today Cobalt has barely 1,100 inhabitants, one grocer y store, one pub, one diner, and no train station. At the same time, Cobalt’s mining boom helped to transform another Ontario town, some 300 miles to the south, into a bustling, modern metropolis. The silver rush needed clever financing, a stock market, and a trading center; thus Toronto’s still-thriving financial center was born.