records of the Royal
Society--being mainly periodic injunctions to Hooke to get on with the
work--until its completion in May 1679. The description which Hooke was
asked to supply was subsequently found among his papers and printed by
William Derham as follows:[9]

The weather-clock consists of two parts; _first_, that which
measures the time, which is a strong and large pendulum-clock,
which moves a week, with once winding up, and is sufficient to turn
a cylinder (upon which the paper is rolled) twice round in a day,
and also to lift a hammer for striking the punches, once every
quarter of an hour.

_Secondly_, of several instruments for measuring the degrees of
alteration, in the several things, to be observed. The first is,
the barometer, which moves the first punch, an inch and half,
serving to shew the difference between the greatest and the least
pressure of the air. The second is, the thermometer, which moves
the punch that shews the differences between the greatest heat in
summer, and the least in winter. The third is, the hygroscope,
moving the punch, which shews the difference between the moistest
and driest airs. The fourth is, the rain-bucket, serving to shew
the quantity of rain that falls; this hath two parts or punches;
the first, to shew what part of the bucket is fill'd, when there
falls not enough to make it empty itself; the second, to shew how
many full buckets have been emptied. The fifth is the wind vane;
this hath also two parts; the first to shew the strength of the
wind, which is observed by the number of revolutions in the
vane-mill, and marked by three punches; the first marks every
10,000 revolutions, the second every 1,000, and the third every
100: The second, to shew the quarters of the wind, this hath four
punches; the first with one point, marking the North quarters, viz.
N.: N. by E.: N. by W.: NNE.: NNW.: NE. by N. and N.W. by N.: NE.
and N.W. The second hath two points, marking the East and its
quarters. The third hath three points, marking the South and its
quarters. The fourth hath four points, marking the West and its
quarters. Some of these punches give one mark, every 100
revolutions of the vane-mill.

The stations or places of the first four punches are marked on a
scrowl of paper, by the clock-hammer, falling eve