In about 1760, Henry Jenkins published a small booklet in which he described his astronomical clocks. This example appeared in the second edition in 1778, where Jenkins described it as the best and most complicated of all his astronomical clocks.The clock has two dials. The lower is a composite dial with the top part showing hours, minutes and seconds. It is flanked on the left by a calendar dial and on the right by a dial showing the times of high tide at various ports. Below these is a large celestial planisphere, which shows the position of the sun and moon in the zodiac throughout the year and the visible stars in the night sky. The upper dial is a heliocentric orrery, which shows the relative positions of the sun and the known planets. The period of 4,334.4 days for the orbit of Jupiter is not common and is thought to be based on Jenkins' own calculations.The clock also plays music. There are twelve tunes including one entitled 'Air by Mudge', a piece written by Richard Mudge, brother of Thomas Mudge the famous chronometer-maker.