Table clocks of the 16th century can be divided roughly into two groups, tower clocks and drum clocks. On the former the dial was vertical and on the latter it was horizontal, occupying most of the top surface of the clock. Some drum clocks were small and plain, and this design eventually developed into the watch and, much later, the marine chronometer. Some drum clocks, however, were quite large, with richly decorated cases and even additional dials. In some instances the clock was arranged to stand on three feet. In the last quarter of the 19th century the shape came into vogue again but now standing upright, in the still-popular style of the alarm clock. A good selling point was that the clocks were portable and did not have to be set in beat like a pendulum clock. Millions of the type must have been manufactured before 1900. A finer version came from France, with the drum of sheet brass, the spring contained in a barrel, and the escapement mounted on a separate platform screwed to the movement. More rarely a tiny pendulum with tic-tac escapement was fitted.