ZURICH.- Numerous works in the 1 April auction sold for multiples of their estimates, witness to continued strength in the Old Masters market. 'Harbour scene with fish market' by Jan Brueghel the Elder, rediscovered by Koller's Old Masters specialist during an insurance appraisal, more than doubled its pre-sale estimate to fetch CHF 741 000 (lot 3039. 'The Alchemist' by David Teniers the Younger, long thought to be by a follower and forgotten in a Swiss family collection until research by Koller's Old Master specialists proved it to be by the hand of the Master, sold for more than three times its estimate at CHF 256 000 (lot 3032).

Bidding for an anonymous North Italian portrait of a lady, circa 1510-20, rose from CHF 10 000 to CHF 78 000 (lot 3019), and a portrait of Dante by a follower of Pontormo had a similar trajectory, from an estimate of CHF 12 000, it fetched CHF 59 000 (lot 3011). Works by Tintoretto (lot 3021, CHF 78 000), Defendente Ferrari (lot 3010, CHF 73 000), and Lucas Cranach the Younger and workshop (lot 3017, CHF 66 000), were also subjects of lively bidding. Among the 19th century paintings, also on 1 April, a Romantic view of the Gulf of Palermo by Carl Wilhelm Götzloff quadrupled its estimate at CHF 32 000 (lot 3238), and a dramatic depiction of the Grindelwald Glacier also sold for over four times its pre-sale guide at CHF 33 000 (lot 3207).

The Old Master Drawings auction on 1 April enjoyed stellar results, with over 230% sold by value. A pencil and wash by Thomas Gainsborough after his 1773 painting 'Peasants returning from market' fetched CHF 85 000 (lot 3469). The Books & Autographs auction on 30 March featured Maria Sybilla Merian's masterwork on the insects of Surinam, which sold for CHF 110 000 (lot 420). Merian completed the work after studies made while travelling alone with her daughter to the Dutch colony in South America in 1699. The top lot in the Decorative Arts auction on 31 March was the 'Effinger' organ clock, of which the provenance could be traced back to its creation in 1783 by Pierre Jaquet-Droz. After spirited bidding, it was acquired by a Swiss museum (lot 1233, CHF 266 000).