A postwar rally in silver futures erupted in a speculative buying frenzy Friday, prompting traders to predict the metal may soon challenge a high set two months ago.

Soybean futures, which historically have followed large moves in silver prices, also rose. Silver and soybeans are considered key inflation indicators and often move in tandem."Silver has gone wild," said a trader in London, where metals traders struggled to catch up with New York's advance.

The May silver contract closed at $4.207 an ounce, up 19.2 cents, after earlier hitting $4.24 on the Commodity Exchange.

The metal has bounced back from a Feb. 22 low of $3.50 - its cheapest since 1974.

The silver market has been supported by an increasingly widespread view that the economy will strengthen in the coming months, boosting industrial demand.

Analysts said the price of silver may soon hit its Jan. 7 high of $4.40 an ounce.

In Chicago, soybean futures on the Chicago Board of Trade jumped 8.25 cents to close at $6.0025 a bushel in the March contract.

A Department of Agriculture report scheduled for Monday prompted many traders to retract sales established earlier in the week.

The USDA was expected to reduce its estimate of Brazil's soybean crop by half a million tons to 17 million tons.

The size of Brazil's crop is important because it is harvested during the Southern Hemisphere's fall, when supplies in the Northern Hemisphere may be growing short.