In case you aren’t familiar with the term, a newel is a central column around which winding stairs are attached. A newel post is (the often highly decorative) post at the end of a stair that anchors the railing. Newel posts are an architectural detail that had many style changes throughout history.
In the early American colonies, simple lathe-turned posts, often similar in profile to the balusters of the railing, or simple tapered square posts were used. Later, in the Georgian period, the turned posts were formed similar to classic architectural columns and then became thinner and delicate in the Federal period. Around 1840, posts began to appear similar to the Greek Revival columns seen on the exterior of buildings, popular at that time. In the third quarter of the 19th century, the newel posts became heavier and broader, as the stair and banister assemblies of that period have massive proportions in the details. Towards the end of that century and into the first quarter of the 20th, square, paneled or faceted posts were popular, often with large caps, heavy mouldings and carvings.
When styles called for broader newel posts many, including lathe-turned round posts, were hollow. When there’s empty voids or hollow spaces in an old homes, there’s often a variety of stories that try to explain a need for that space. Apparently, empty, concealed spaces must have always been intentional – usually for secret compartments. The most frequent stories about the voids in large newel posts describe them as being a chamber for important house papers, like the deed for the house or the architectural plans. Some posts are topped with a decorative cap or finial and when it finally comes loose, reveals a small compartment. The most frequent story I’ve heard, was a coin would be placed in the compartment by the house-builder when completed.
Some newel post caps have a small, inlaid button in the center, often of ivory and sometimes mother of pearl. In New England, I’ve heard it called a “mortgage button” several times. The story claims that when a house was paid in full, a hole was drilled into the center of the newel post. Either the mortgage paper was rolled up tightly to fit or burned and the ashes interred in the hole and capped with the button. In the mid-Atlantic, I’ve heard it called an “amity button” and it is said to be installed when the debt with the builder was settled.
I’ve never found anything inside of a newel post and haven’t read anything from a credible source to convince me these stories are fact. I’m always skeptical when I hear old-house folklore though – that’s part of my job.