LONDON.- A stunning discovery at Bonhams turns out to be a gift passed between two of the most important statesmen of the late Qing Dynasty, who attempted to modernise China and represented the Qing Dynasty in diplomatic negotiations with Western powers. A magnificent and important pale green jade mountain, dating from the 18th century, and dedicated by Li Hong Zhang to Prince Gong will be the highlight of Bonhams next Chinese Art Sale on May 17th in New Bond Street, London. Estimated to sell for £400,000 to £600,000, the large jade boulder is carved as a mountain peak in high relief with four sages and an attendant on a narrow ledge above a stream, amidst a mountainous landscape with pine and wutong tress. The reverse side is carved with bare rocky cliffs and pine trees, with a nine character inscription incised on an overhanging precipice with traces of gilt