The radial head is held in place by a ligament called the annular ligament.
Besides the sugar-refinery already mentioned, there were in Ig00 four tobacco factories, a national printing-press, an annular furnace for brick-burning, an iron-foundry and several blast-furnaces, under the management of the state.
From 1848 to 1878 it was but with few interruptions employed for observations of nebulae (see Nebula); and many previously unknown features in these objects were revealed by it, especially the similarity of "annular" and "planetary" nebulae, and the remarkable "spiral" configuration prevailing in many of the brighter nebulae.
When the annular ligament is torn, a part of it slides upward and becomes trapped in the elbow joint, which is very painful condition.
Features include perfectly equilibrated hands, precision gears that require no lubrication, and an annular balance that produces a mere two vibrations per minute.