This plique-a-jour enamel and silver vase was offered for sale at Leo Kaplan Ltd. in New York City. It was made by Gustav Gaudernack while he was working at David-Andersen in Oslo, Norway, about 1900. It is 8 inches high.

Art-nouveau designs are very unlike the slick modern designs favored by today’s craftsmen. The style was international, but its most extreme examples were European. Gustav Gaudernack (1865-1914) was a talented goldsmith who worked in Norway. He was born in Bohemia and while in his 20s studied glassmaking and enameling in Vienna. In 1891 he moved to what is now Oslo, and from 1892 to 1910 he was the leading goldsmith and designer for David-Andersen, a firm that is still making silver, gold and enameled jewelry. Gaudernack was also an expert at plique-a-jour enameling. He opened his own enamel workshop in 1910 and experimented with enameling techniques so he could make large pieces. His work required great technical skill as well as artistic talent, but it’s not well-known among American collectors.

Q: I would like information about a wicker strolling chair with a cane seat. A metal tag attached to the back says, “Made by the Colson Company, Elyria, O, USA, Model C15.”

A: The Colson Co. was founded in Elyria, about 30 miles southwest of Cleveland, in 1917. Fred Colson formed the company from the remnants of two other Ohio firms that had been manufacturing tricycles and rolling chairs for adults and the handicapped. Colson expanded production to include additional wheelchair models, service carts, stretchers, bicycles and scooters. During the Depression, Colson Co. went bankrupt and was reorganized as Colson Corp. Your “Colson Co.” wheelchair was made between 1917 and 1933. Antique wicker wheelchairs sell for $100 to $1,000, depending on style and condition. Colson Corp. was sold in 1953, but in 1957 its wheelchair division was purchased by three former employees. In 1971, it was one of two firms that merged to form Invacare Corp., which introduced a motorized wheelchair with computer controls in 1982. Invacare is still in business as a major manufacturer of home healthcare products.

Q: My glass vase is made of bubbly clear and colored glass. It’s very modern-looking and is marked “Maleras” on the bottom. Can you tell me who made it?

A: Maleras Glasbruk is one of the Swedish glassworks founded in the 1920s. It made tableware and art glass. The glass was cut, engraved, pressed or blown. Some pieces were made of mottled colored glass; others were clear glass that was engraved with a design. The company employed a series of artists, engravers and designers who later worked for Swedish glass companies like Kosta and Orrefors. The company was purchased by Mats Jonasson in 1988 and is still in business.

Q: I own an oval serving platter with a hand-painted picture of three cows in the center. The picture is signed “R.K. Beck.” The platter is 14 1/2 inches long by 11 1/8 inches wide and has a 12-sided edge (rather than a smooth oval). The border is copper-colored, and the mark on the bottom is “S.C. Co., Martha Washington.” What can you tell me?

A: The picture on your plate is transfer-printed, not hand-painted. R.K. Beck was an artist who specialized in painting wildlife and other animals. Many of his paintings were used to create transfer prints for dishes. The print on your platter was used on dishes made by several different Ohio and West Virginia potteries. Your platter was made by the Sebring China Co., founded in Sebring, Ohio, around 1909. “Martha Washington” appears to be a shape name used by both Sebring China and the French China Co., which also operated in Sebring. In fact, the five Sebring brothers who founded the town of Sebring (about 33 miles southwest of Youngstown) also established several potteries that apparently shared patterns and shapes. Sebring China went out of business in about 1929, but other Sebring potteries remained open into the 1940s and ’50s. Most R.K. Beck platters in excellent condition sell for $50 or so.