Dating to the time of their reputed inventor, Benjamin Franklin, rocking chairs rest upon two distinctive curved feet known as “rockers,” enabling them to swing back and forth. With gliders--introduced in the 1890s--this swinging motion is achieved by a mechanical pivot that in turn sits upon a fixed foot. Unlike traditional rocking chairs, gliders are usually upholstered.
Look at the overall shape of the rocking chair in order to identify an old example. On the earliest examples--before 1830--the only curved elements are the rockers. As the 19th century progressed, curved armrests and backs were introduced in order to create a pleasingly uniform design. A slight awkwardness or mismatch in the design, therefore, can be an indication of a rocking chair's age.
Check the rocking chair's construction. Prior to the 1860s, rocking chairs were put together with mortise-and-tenon joints–one piece carved to fit snugly into another–and turned from good-quality, solid, local timbers. In the latter half of the 19th century, the market was dominated by inexpensive bentwood rocking chairs imported from Germany; they look as if they are made of cane. American firms competed with novelties such as the glider.
Look for a fixed foot that has an attached mechanism for rocking the seat back and forth to identify an old upholstered glider.
Examine the glider's construction material. Gliders from 1890 to 1910 are mostly made of oak with an upholstered seat and back. That upholstery is often edged with studs and is usually of a thick, carpetlike fabric.
Before buying a rocking chair, turn it upside down and look for wear to the underside of the rockers. Years of rocking should have created a distinctive pattern of wear, while new rockers probably still display saw marks.
Because a rocking chair's distinctive rocking motion puts it at risk from breaks, check an old rocking chair thoroughly for damage and repairs.