Creative cabinetmakers have enjoyed making dual-purpose furniture for centuries. A desk with a drawer that opens to a bed, a chair that can be flipped to become library steps or bed steps, a table with a top that flips up to become the back of a bench, and other clever examples were made by the 18th century. There was even an 1866 patent for a piano that opened up to be a “bedroom” with a bed and chest of drawers. But an 1883 combination sofa and bathtub is our favorite.

Children’s furniture was a special challenge. A Victorian folding chair that could become a stroller, rocker, carriage or highchair is often found today. In the mid-19th century, an English mahogany child’s chair was made with a tablelike stand. Together the parts made a highchair. Apart it was a small chair and table the right size for a child. It sold recently in New Orleans for $1,998.

The chair-into-steps and the child’s convertible stroller are ideas that are still in use. But we doubt any new bathtub-sofas are being made.

When did the modern-type engagement ring, the single diamond on a decorated band, become popular? What would an antique engagement ring look like?

Before the 15th century, a bride was given a simple iron ring, if any ring at all. But in 1477 Archduke Maximilian of Austria gave a diamond engagement ring to Mary of Burgundy. The idea spread, but engagement rings were made with many different stones and decorated bands for many centuries. In 1870 diamonds were found in Africa and the large supply made the price drop. The well-to-do, not just royalty, could afford a diamond engagement ring. In 1866 the prong-mounted diamond ring by Tiffany &Co. was the ring to have. In the 1900s, new tools allowed jewelry makers to create elaborate decorations, including pierced filigree and graining. Platinum and white gold replaced yellow gold in popularity. Old and new style rings are still made. Many recent rings are very plain and use gold, platinum or even steel as the band.

About 15 years ago, I bought a cast-iron Kenton toy cement mixer at an Atlantic City antique show. The mixer’s body is embossed “Jaeger” on the sides, and the toy has rubber tires. It’s 8 1/2 inches long and 7 1/2 inches high. Is it valuable?

You have a very collectible toy that Kenton Hardware Manufacturing Co. introduced in 1932. Kenton was founded in Kenton, Ohio, in 1890 to make locks. Within a few years, it began making toys. Kenton made four cement mixers using the brand name Jaeger, referring to the Jaeger Machine Co. of Columbus, Ohio. The two models with rubber tires, including yours and a smaller model, date from about 1940. World War II stopped production at Kenton because metal was needed for munitions, not toys, and Kenton closed in 1952. If your toy is in excellent condition, it could be worth $500 or more.

I am curious about my miniature rose bowl. It’s marked with a crown surrounded by the words, “Coalport Bone China, Made in England, AD 1750.”

Coalport Porcelain Works, also known as Coalbrookdale, dates back to the 1790s — even though the “AD 1750” in your mark supposedly refers to the year the company was founded. Coalport started making miniatures, including rose bowls, tea sets, pin trays and baskets, in the 1880s. The mark on your rose bowl was used after World War II until about 1960. It would sell for about $10.

I have four glass flasks originally sold filled with Lestoil liquid cleaner. The bottles were available for a limited time. Are they worth anything.

The Lestoil Co. of Holyoke, Mass., sold its liquid cleaner in special-edition reproduction glass flasks in 1963 and 1964. The reproductions were marked only with a paper label around the neck. The flasks resemble 19th-century historic whiskey flasks and came in streaky blue, green, amethyst, amber or clear glass.

Clues to tell a reproduction from an old flask: a reproduction has a rolled collar and a smooth bottom (sometimes with a mold number); an antique flask has a plain, straight-up lip and a pontil mark on the bottom. Many of the old flasks sell for thousands, however the Lestoil bottles only sell for about $10 apiece.

I came across a walnut chest of drawers 5 feet tall. It has eight drawers that are exceptionally deep (261/2 inches). When you slide the drawers out, they tilt downward. A metal plaque on the front says “Schlight &Field Co., Rochester, N.Y.” A paper tag on the drawer says “made by Jacob Hartman on Nov. 1, 1889.” Can you tell me what the chest was used for?

Your “chest of drawers” is probably a piece of 19th-century office furniture called a “paper file” or “flat file.” It was made by Jacob Hartman, but used a filing drawer mechanism with an 1888 patent owned by Schlight &Field Co.

The mechanism held papers down in the drawers, which could tip so it was easier to find the papers you were looking for. Paper files the size of yours, in excellent condition and not repainted, can sell for $400 or more.

Write to Kovels, The Herald, King Features Syndicate, 888 Seventh Ave., New York, NY 10019.

&Copy; 2008 by Cowles Syndicate Inc.

On the block

Current prices are recorded from antiques shows, flea markets, sales and auctions throughout the United States. Prices vary in different locations because of local economic conditions.

Civil War map, Ohio, color, railroads, towns and rivers, Johnson’s Atlas, 1863, 26 x 17 inches, $80.

U.S. Military Academy uniform, blue wool, ivory trim, silver buttons, 1880s, size large, $115.

F.D.R. bottle opener, figural braying donkey, cast iron, raised initials on front, c.1932, 3 1/4 x 3 1/4 inches, $160.

Washstand, painted, scrolled backsplash, pierced top, one shelf, c.1830, 27 x 14 inches, $285.

Medical amputation saw &knife, wooden handle, 1861, 17 inches, $315.

“Gone With the Wind” paper dolls, Clark Gable, Vivien Leigh, Anne Rutherford, Merrill Publishing, 1940s, $410.

Gen. MacArthur doll, composition, painted features, molded hat, Freundlich, 19 inches, $500.

Toy soldier set, cavalry and infantry, lead, Heyde, 1900-20, 2 inches, $625.

Patchwork quilt, Trip Around the World pattern, purple, pumpkin, maroon &blue, 1890s, crib size, $1,455.

Remington advertising sign, waterproof shells, image of ducks, paper, stand-up, 1923, 40 x 26 inches, $1,540.