Laws of Financial GravityCommentary on commodity markets which posted their worst-ever performance in 2008 reflects Mark Twain’s remark: "I am not one of those who in expressing opinions confine themselves to facts."Unlike financial assets commodities for the most part are subject to the laws of economic gravity - supply and demand. Individual commodities are also highly idiosyncratic - you can’t drink oil nor can you run your car on gold (though they seem to run quite well on corn tortillas).The key to commodities is demand. Higher prices -- in oil for example -- led to a sharp reduction in ...