Daniel Quare, London, b.1649, Clockmakers' Company 1671, Master 1708, in partnership until his death in 1724 with Stephen Horseman. Appointed Keeper of the King's Clocks and allowed to enter the palace by the back stairs even though he was a Quaker; also a maker of mathematical instruments and barometers

This highly important royal barometer can be associated with the celebrated group of five barometers, two by Quare and three by Tompion in the Royal Collection. All five were presumably commissioned by William III to form part of the furnishing for his newly enlarged Palace at Kensington. The present barometer, the only one to have strayed from the group, bears several points of resemblance to Tompion's siphon tube barometer, (vide Nicholas Goodison, English Barometers and their Makers 1680-1860, pl.140. Both are of architectural construction surmounted by a large decorative urn finial containing the reservoir, both incorporate calendar dials and have an identical glazed frame to the register plates which have similarities of layout and engraving. The Tompion barometer may also have originally had columns flanking the plates as in the present instrument. These likenesses would tend to suggest that they were made in collaboration. Dr Robert Hooke (1635-1703) is accredited with the invention of this particular form of siphon tube. Published in Micrographic in 1665 he "contrived to show all the minute variations in the pressure of the air". The large bulb or 'bolt-head', which in the present instrument is covered by a silver mounted urn finial, acted like a conventional cistern necessitating the scale to be read in the short limb. This in turn meant that the scale had to be inverted so that a rise in the visible level of mercury is associated with a fall in barometric pressure. p