hat the two clocks were very
closely related in other ways too. This, circumstantial though it be, is
evidence for thinking that the weight drive and some form of escapement
were known to Richard of Wallingford, _ca._ 1320. It would narrow the
gap between the clock and the protoclocks to less than half a century,
perhaps a single generation, in the interval _ca._ 1285-1320. In this
connection it may be of interest that Richard of Wallingford knew only
the Toledo tables corpus, that of the Alfonsine school did not arrive in
England until after his death.

There are, of course, many literary references to the water-clocks in
medieval literature. In fact most of these are from quotations which
have often been produced erroneously in the history of the mechanical
clock, thereby providing many misleading starts for that history, as
noted previously in the discussion of the horologium. There are however
enough mentions to make it certain that water clocks of some sort were
in use, especially for ecclesiastic purposes, from the end of the 12th
century onwards. Thus, Jocelin of Brakelond tells of a fire in the Abbey
Church of Bury St. Edmunds in the year 1198.[33] The relics would have
been destroyed during the night, but just at the crucial moment the
clock bell sounded for matins and the master of the vestry sounded the
alarm. On this "the young men amongst us ran to get water, some to the
well and others to the clock"--probably the sole occasion on which a
clock served as a fire hydrant.

It seems probable that some of these water clocks could have been simple
drip clepsydras, with perhaps a striking arrangement added. A most
fortunate discovery by Drover has now brought to light a manuscript
illumination that shows that these water clocks, at least by _ca,_ 1285,
had become more complex and were rather similar in appearance to the
Alfonsine mercury drum.[34] The illustration (fig. 19) is from a
moralized Bible written in northern France, and accompanies the passage
where King Hezekiah is given a sign by the Lord, the sun being moved
back ten steps of the clock. The picture clearly shows the central water
wheel and below it a dog's head spout gushing water into a bucket
supported by chains, with a (weight?) cord running behind. Above the
wheel is a carillon of bells, and to one side a rosette which might be a
fly or a model sun. The wheel appears to have 15 compartments, each with
a central hole (perhaps similar to that in