What factors affect the index of a refraction of liquid?

Hong Kong: What were the factors behind Hang Seng Index's massive plunge of 90% in 1973?

• 1973 was a bad year for global stock markets. But a plunge of 90% was really incredible even by 2008 standards. Why did 1973 oil crisis affect Hong Kong so much? I believe this was the worst in Hang Seng's history. A side question. Who were the big winners, if any, who emerged in this massive plunge?

• Answer:

  There was a boom-bust situation between 1972 and 1974. What happened in 1972 was that HK started to peg the HKD against the US dollar rather than the British pound.  Because the US was undergoing a lot of inflation the effect of the peg was to push massive amounts of US dollars into Hong Kong which created a bubble because HK is a rather small economy. Now the trigger for the crash was the Yom Kippur War and the Arab oil embargo in 1973, when the embargo hits, you suddenly have to pay a ton of money for oil, and since you've pegged your currency, you can't print money to cushion the shock.  The big drop in the Hang Seng ends when HK decides to float the HKD, which they did until the early 1980's.