1a. A geographical astrolabe engraved on a circular disc rotating within an hour scale (1-12 x 2 reading to 15 minutes) also marked meridies (south) along one edge. Consisting of a stereographic projection of the Earth from the North pole onto the plane of the Earth's equator showing named continents and seas (originally silvered) and with the tropics and equator named. Over this plate rotates a rete consisting of the ecliptic circle only with names, signs and a rule carrying a latitude scale.
1b. A circular map of the Low Countries centred around Breda and Dordrecht with the names of approximately 120 towns together with rivers and inlets, fishermen lowering their nets into the sea (originally silvered) and sea monsters. Pivoted in the centre is an index-arm marked HOC REG CO? SITV: VRBI with a sliding cursor to which is pivoted a second arm used to ascertain the bearing of one town from another. Around the edges of the map twelve compass directions are marked.
2a. A horizontal string-gnomon sundial with inset with inset central compass and five hour scales for degrees of latitude 42, 45, 48, 51 and 54. Spring-loaded folding arm for attaching the upper end of the gnomon in one of the five positions corresponding with the latitudes marked on the plate.
2b. The latitudes of 35 towns in the Low Countries situated between 50 and 53 degrees surrounding the underside of the compass which is decorated with engraved foliage, and a spring drum containing the reserve for the gnomon.
3a. A solar aspectarium explained by the inscription ORBIS INTERIOR SVRGET RVTILANS SOL QUANDO CADATVE EXTERIOR LVCIS SPATIUM TIBI DENOTAT (the shining sun rises on the inner disc, when the sun sets the outer shows you the length of light), consisting of a central volvelle engraved with a diagram of astrological aspects of the planets (trine, quadrature and sext), a circular aperture for the sun and two indexes which provide direct readings and conversions between the three hour scales engraved concentrically around the volvelle.
3b. A rectilinear or 'de Roias' horary diagram, also refered to as an Organum Ptolomei, used, with the rule pivoted at the centre, to determine the times of sunrise and sunset for any latitude, is engraved on the recessed plate, a month calendar engraved on the surrounding rim. This plate is also a nocturnal which, in conjunction with the separate extension, can be used to sight Ursa Major in relation to the Pole star to determine the time at night. The hours on the plate are marked by fourteen buttons and a sharp point at 12 form 'reading' the scale by touch in the dark. The whole is explained by the inscription NOCTVRNALE VERSVS POLVM ARTICVM VEL VRSAM MELORES APLICANDVM (the nocturnal is directed towards the Pole star or the Great Bear). For convenience in use, the hinge pin of this plate can be removed and the plate used separately from the rest of the compendium.
The instrument is completed by a separate wind-vane (which may be mounted at the centre of plate 1) and a chased and folding plummet holder. Both of these accesssories are usually missing from surviving compendia.
The Fine Arts Museum of San Francisco, 1978
The Folger Shakespeare Library, Washington D.C., October 1986-March 1987
Although early in his output, Schissler displays in this instrument a mastery of both layout and execution. Intended to provide wealthy travellers with a maximum of useful information, Schissler's compendia were often, as in this case, designed to order for a specific part of Europe. Combining terrestrial and celestial indications in a conveniently portable form, they typify the desire for instruments that are universal, elegant and ingenious, so charateristic of the Renaissance. An almost identical instrument in the Poldi Pezzoli Museum, Milan, dated from the same year, but with the map drawn for Central Europe and with the latitude range adjusted accordingly, should perhaps be considered as a companion piece to the present instrument.
Sotheby's would like to thank Anthony Turner for his assistance in cataloguing this lot.
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