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Inventory no. 51021 - Former Display Label


Gilt brass. Signed, "MARCVS PVRMAN MONACHI FACIEBAT ... ANNO 1599".

Made for use in latitude 48°. One of the three raised bosses on the foot hinges open to reveal a small compass (the present compass plate is a 19th century replacement).

The chalice or cup dial is derived from the scaphe of which examples are shown here. There are two sets of hour-lines on this instrument. One set, for Italian hours, is inscribed "Horarium sine aqua" and is for use when the cup is empty. The other set, for ordinary hours, is inscribed "Horarium ex perspectiua radiorum refractorum aquae" and is drawn to compensate for the refraction which occurs when the cup is filled with water. Opposite the hour-lines is a vertical scale, used to determine the sun's altitude.

Formerly in the Rosenheim and Sir John Findlay Collections.

Purchased in 1961 with a grant from the National Art-Collections Fund.

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