Modeling the Earth's Magnetic Field Click on any image for a larger view.

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AN ELECTROMAGNETIC TERRELLA, probably Italian, c. 1830, numbered "110" but lacking two name plaques. This fine physics demonstration apparatus presents a model of the earth, with its magnetic field generated by electric currents. The earth itself is a 12" (30 cm) diameter hollow painted steel sphere wrapped with insulated wire coiled around a broad equatorial band. The poles are marked "N" and "S," and the coiled wire terminates with slipping conductors at each end of the horizontal axis. From there wires lead to fixed terminals for connection to a source of electricity. Thus the sphere can be turned freely by hand yet maintain electrical contact. The whole is mounted within a fine beautifully grained mahogany stand with 20-3/4" x 11-1/4" (53 x 29 cm) oval base, and 15-3/4" (40 cm) tall turned mahogany columns carrying large boxwood clamp screws as well as supports for small magnetic needles used to demonstrate the earth's field direction and polarity. Condition is generally fine, with noticeable losses to the paint on the sphere, one small dent, and some losses to the fixed wiring on the columns.

This is a very rare example of electromagnetic terrella, as invented independently by Peter Barlow and Leopoldo Nobili, in the 1820's. In use, the electric current passing through the equatorial coils generates a magnetic field simulating that of the earth. By rotating the earth to different (latitudinal) positions, the local field direction is best shown by an auxiliary little dip needle placed on top, and by the compass needles on the sides. We are aware of very few other electromagnetic terrellas which have survived, notably three smaller simpler ones, all Italian: an unsigned one in the Museo Galileo, one signed Marcellino of Alessandria, and one signed C. Dell'Acqua of Milan in the University of Pavia (illustrated in G. Turner, 1983). A more complex French one is in a private collection. Finally, there exists an identical twin of the present instrument in the exceptional Cabinet of Physics of the University of Coimbra in Portugal. (9026) $7500.


Fine Early Example of Reflecting Telescope Click on any image for a larger view.

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DIMINUTIVE EARLY CASE-MOUNTED GREGORIAN TELESCOPE, probably English, c. second quarter 18th century. The 8-5/8" x 3-1/2" x 2-3/4" (22 x 9 x 7 cm) mahogany or rosewood case has oak bottom and beveled slide-off lid, plus inset brass mounting plate and beautiful brass escutcheon. The brass telescope assembly mounts to the lid, by tapered steel screw and turned brass pillar to altazimuth mount. The main tube is 7-1/4" long and 1-5/8" in diameter, fitted with spring-loaded speculum metal primary mirror, speculum secondary mirror on adjustable mount driven by external focusing rod, erecting eyepiece assembly with two lens elements and two apertures, screw-on red solar filter, and turned end cap. The system gives remarkably fine images, even in daylight when the Gregorian design suffers from off-axis light. Condition is fine noting some darkening to the brass, a couple of replaced mounting screws, and old repair to the lock.

Various details point to an early date -- the use of oak as a secondary wood, the escutcheon form, telescope design details, the diminutive size, the case-top mounting, etc. We have seen an even smaller case-mounted Gregorian by Edward Scarlett, and note James Short's frequent use of this design. (7044) $4500.


Beautiful Mixed-Material Construction Click on any image for a larger view.

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HANDSOME ENGLISH MONOCULAR BY AN UNCOMMON MAKER, third quarter 18th century, signed (stamped) on the drawtube "S. Iohnson, London." Measuring only 2-3/8" (6 cm) long closed, this little telescope is constructed in a wonderful combination of materials typical of 18th century fashion, with wood main tube bound in red-stained ray skin, card drawtube bound in green-stained vellum with stamped decoration, dark-stained ivory mounts, and internal diaphragm of wood. Condition is very fine, noting some (rather attractive) wear to the stain on the edges of the ivory mounts.

The maker would have been Samuel Johnson, apprenticed to the famous optical instrument maker James Mann in 1738, made free in the Spectacle Makers guild in 1745, and working under the wonderful trade sign of "Sir Isaac Newton & Two Pair of Golden Spectacles" (see Clifton). (9036) $1950.


Zodiacal Calendar, Feast Days, etc. Click on any image for a larger view.

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SILVER AIDE-MEMOIRE, German, 18th century, the thin silver plaque measuring 1-7/8" x 3-1/8" (4.8 x 7.9 cm) and mounted on the reverse with a layer of embossed paper with gilt highlights showing two dogs romping amidst floral patterns The silver is hand-engraved with seven columns, giving for each month of the year the number of days in each month, the principal feast days and holy days with their dates, the sun's Zodiacal position with charming vignettes of the constellation figures, the length of daylight in hours, the length of night, the hour of sunrise, and the hour of sunset. It is pierced with a hole in a decorative rosace, suggesting it once was attached to an ivory notepad, perhaps. Condition is fine. Attached is an early private ownership tag, giving the date of acquisition into that collection in 1882! (8050) $2800.










Handheld Reflecting Telescope, in Fishskin Case Click on any image for a larger view.

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MINIATURE GREGORIAN TELESCOPE, English, c. third quarter 18th century. Measuring 7-1/4" (18 cm) overall, complete with turned brass end cap, the instrument has bright speculum metal mirrors, two-element erecting eyepiece system, and external screw focussing to the secondary mirror. Craftsmanship is excellent, and it gives superb images even in daytime. The telescope is contained in its wonderful original shaped case of wood lined with green velvet and covered in black fishskin. Condition is very fine throughout, noting a bit of rubbing to the original lacquer finish on the brass, and loss of one small semicircular end to the case. The miniature Gregorian telescope is known in very few examples; we have had one by Stedman of London (Tesseract Catalogue 52 Item 7), and one unsigned (Catalogue 40 Item 6). A splendid example. (8013) $4950.


Important American Diamond-Ruled Grating Click on any image for a larger view.

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ORIGINAL ROWLAND / BRASHEAR DIFFRACTION GRATING, IN GEARED MOUNTING, American, 1895, signed by hand with a diamond stylus, directly on the speculum surface "Plate prepared at the Astronomical and Physical Instrument Wrks. of Jn. A. Brashear, Allegheny, Pa., USA; AE; Ruled on Rowland's Engine, Johns Hopkins University, Baltimore, Md., USA, 1895; 14438 lines to one inch, 568+ to 1 m/m." This remarkable grating is ruled directly on a 2-1/2" (6 cm) square block of speculum metal, with a polished and ruled area 1-3/8" x 1-7/8". It is mounted vertically in a carrier which is rotatable by circular rack and pinion on a substantial base with three leveling feet, all the mounting made of handsome clear lacquered and blackened brass. A glass cover slide protects the grating, which shows some rubbing to the surface, but which produces very good spectra. Condition is very fine throughout.

Henry Augustus Rowland (1848 - 1901), an extraordinary physicist / engineer, made landmark progress in the design and manufacture of ruled gratings, his ruling engines being the best in the world for several decades. John Alfred Brashear (1840-1920) was a mechanical genius who produced numerous superb telescope objectives, and who excelled at creating extremely accurate surfaces (uniform to 1/5 of a light wave!) on speculum metal plates for Rowland's gratings.

A fine example of an original grating, this one graded "superb" by these master makers. (Featured in "Wondrous Devices" exhibition, Hudson River Museum, 2018) (8057) $2400.


Eighteenth Century "Calendarium Perpetuum" Click on any image for a larger view.

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GERMAN PERPETUAL CALENDAR, 18th century, made of gilt and silvered brass, 1-7/8" (4.7 cm) in diameter. On one side the rotatable "Calendarium Perpetuum" shows the days of the week (in German, and marked with their planetary signs) against days of the month, and has floral patterns hand-engraved in the open spaces. The other side gives, in seven readout windows defined by its rotatable disk, month of the year with its number of days, tabulation of the important saints' and feast days in the month, sun¹s Zodiacal position, length of day, length of night, time of sun rise, and time of sunset. There is further floral engraving, as well as inclusion of a seated person amongst the vines. The Zodiacal signs are identified by amusing little hand engravings. A good example in very fine condition. (7037) $2400.


Early English Quadrant Click on any image for a larger view.

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FASCINATING EARLY QUADRANT, English, mid-17th century. This very thin brass quadrant is 3-3/4" (9.5 cm) in radius, hand engraved on one side, with practice engraving of several numerals and letters on the reverse. There is a circumferential quadrant scale divided every degree, for use in measuring the angular altitude of sun, moon, stars, mountains, buildings, etc., by sighting along the edge and reading against a little plumb line which would be suspended from the apex. Next is a calendrical scale, laid out for a vernal equinox of approximately 11 March (consistent with the Julian calendar), and for a latitude of 52° (close to that of London). The sky grid of arcuate hour and azimuth lines is crossed by the ecliptic, and is consistent with Edmund Gunter¹s design of 1623. There is an edge scale of solar declination, and in the corner a fascinating shadow square, each leg divided every 5 from 0 to 50. Within the square is a scale hitherto unknown to us on surviving quadrants. The 90° angle is divided radially into ten equal segments labeled "J, F, M, A, M, D, N, O, S, A," and with "J, J" on the center line. And concentric arcs indeed carry variously the numbers 28, 30, and 31, which all align, rather primitively, with the letters, giving an aide-mémoire for the number of days in each month. The apex of the square has hand-engraved decoration of a very distinctive style found on some 17th and early 18th century English instruments: compare with that on a plane table rule (Tesseract Catalogue 76, Item 30) and that on a boxwood compendium attributed to Sutton (Wynter and Turner, p. 132). Condition is fair noting much old pitting to the brass, and only remnants of the little pinhole sights remaining. The instrument was reputedly purchased in Wales many decades ago, and probably suffered outdoor weathering a very long time before. Nevertheless it is a fascinating early quadrant. (7077) $4500.


Ringard's Oval Lenses Click on any image for a larger view.

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ELLIPTICAL LENS BINOCULARS, French, mid-19th century, signed in the eye mounts "Jumelle Elliptique, Brevetée S.G. D.G., Ringard Opticien, R. S't. Martin, 199, Paris," and with the maker¹s "RD" mark. Measuring 4-3/4" (12 cm) wide, and made of beautiful contrasting black enameled and gilt brass, with lens mounts and central focusing knob of hard rubber or wood, the binoculars have highly elliptical tubes fitted with singlet eye and objective lenses. Their unusual elliptical form provides the user with a field of view much wider horizontally than vertically, in a quite compact instrument. Condition is very fine noting some small chips to the mounts. The original leather case is rather rough, but has interesting fouled anchor motifs on the brass clasp.

M. Ringard, Parisian optician, crafted these rather remarkable binoculars. His techniques of cutting and centering the oval lenses is specially treated in an 1848 paper in the Bulletin de la Société d¹Encouragement pour l¹Industrie Nationale. (9043) $850.


Binoculars with a Handle Click on any image for a larger view.

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ELEGANT OPERA GLASSES, French, mid-19th century, signed twice ³Bianchi, rue du Coq St. Honoré No. 11 à Paris.² Measuring 4-1/2² (11 cm) wide overall, the binoculars are constructed of gilt-lacquered brass, with simulated tortoiseshell enameled main tubes, central geared focus with ivory thumbscrew, and swing away horn handle. In fine functional condition, they are complete with the shaped wood case covered in simulated red Morocco leather and lined with silk. (7036) $650.


For Your Walking Stick or Cane Click on any image for a larger view.

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THE "TOURISTEN-FERNSEHER," A CANE-MOUNTING OPEN-AIR TELESCOPE, German, c. 1900, comprising two quite portable lenses set in tin mounts, contained in the original 3-1/2" x 5" (9 x 13 cm) card box with instructions. Each lens holder is designed to clamp onto one¹s walking-stick, thus forming an impressive Galilean telescope with a 2" diameter objective and focal length of approximately 20". It functions well, and is in good condition, the box rough. (Featured in "Wondrous Devices" exhibition, Hudson River Museum, 2018) (9035) $495.


Lovely Patented Binoculars Click on any image for a larger view.

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ELEGANT IVORY-BOUND OPERA GLASSES, French, 19th century, signed around each eye lens "Par Brevet d'Invention et de Perfectionnement." Measuring 4" (10 cm) wide overall, these elegant low power binoculars are made of gilt brass with main tubes bound in splendid turned ivory rings. There is center-focus, and a swiveling ivory handle. Condition is fine noting that each ivory ring has a single age check, formed as the ivory shrank on the brass. (7047) $550.


Feast Days, Length of Night, Time of Sunrise, etc. Click on any image for a larger view.

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FRENCH PERPETUAL CALENDAR, c. 1800, set in a 12" x 17-1/4" (30 x 44 cm) heavy oak surround, behind glass in an old gilt wood frame. The calendar itself is 10-1/2" x 15-1/2", of heavy card, hand decorated in ink and watercolor, with a collage of a flower (pansy?) in bloom. An ornate arch design is supported by twin columns on a faux-marble base, and is surmounted by a finial and a fine armillary sphere and globe. There are two volvelles, the outer with days of the month which can be set against a fixed scale of days of the week, this latter showing each day in French, its corresponding planetary symbol, and planet name. The inner volvelle rotates independently, and is set to the month. Relevant information is then visible in six windows: the time of sunrise (being the average for that month), time of sunset, length of day, length of night, Zodiacal sign symbol (beautifully drafted and watercolored), and list of the principal feast days. Condition is fair only, with losses and some browning in addition to the original brown wash, and the central pin or pulley replaced. Nevertheless it is an unusual, charming, and quite well-painted work of art and science. (9075) $1250.


High Precision Time Setting Click on any image for a larger view.

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HENRI ROBERT'S ASTRONOMICAL BALANCE, French, c. 1835, signed "henry ROBERT, horloger a Paris. invenit." The "balance" is constructed with a 20" (51 cm) long lacquered brass tube fitted to a flat brass suspension bar and two large brass chain links. When suspended, the whole can rotate about the zenith direction, and the tube can pivot in its vertical plane. The tube itself is fitted with a tiny lens and pinhole at one end, and a removable target at the other. The target is inscribed with a grid of lines identified by dot patterns, and is inclined to the optical axis, and visible through a cut in the side of the tube. Condition is fine and complete, retaining about half the original lacquer finish.

Henri Robert (1795 - 1874) was a clock-and-watch maker and prolific inventor. He worked with Breguet, establishing his own business in 1832, and became "Clockmaker to the Marine" as well as "Clockmaker to the Queen." This is his astronomical balance, by which one can determine the error in a watch or clock with high precision, simply by observing the sun (see Archives des Découvertes et des Inventions Nouvelles...pendant l¹année 1833). One suspends the balance in sunlight sometime before noon, aligns it with the sun, and, using the watch or clock in question, notes the exact times that the spot of sunlight crosses the lines on the target (as the sun ascends in elevation as it approaches the maximum at noon). One again notes the exact times that the same lines are crossed after noon. An average of the times should be 12:00:00 noon -- if not, one resets the watch by the difference. The maker / inventor offered the apparatus in two sizes, this one the larger and more accurate, giving time corrections to five seconds. This is a remarkable survival, complete even with the original suspension chain links. We are aware of only one other example of Robert's invention, that in the smaller version (Orologi e strumenti della Collezione Beltrame, 1996). (Featured in "Wondrous Devices" exhibition, Hudson River Museum, 2018) (9040) $5500.


Astronomical Quadrant with Rackwork Motions Click on any image for a larger view.

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JONES' IMPROVED ASTRONOMICAL QUADRANT, English, early 19th century, signed "W. & S. Jones, 30 Holborn, London." This handsome lacquered brass instrument stands 10" (25 cm) tall on its tabletop base with three leveling screws. The base has a circumferential degree scale, and is centered by a rotating disk which carries the instrument on central pillar, and which is fitted with crossed spirit levels, internal pinion and ring gears, and one-arcminute vernier. Atop the openwork pillar is mounted the 4-1/4" (11 cm) radius openwork quadrant with 0° - 90° scale, one-arcminute vernier, and pinion with external rack. Thus the instrument functions as a geared altazimuth theodolite. It is aligned not with sight vanes but with a right angle telescope with sliding focus to both the objective and eyepiece, fitted with solar filter. Condition is very fine, complete, and functional; the brass is spotted but retains most of its original clear lacquer finish. This is a very rare example of Jones' improved astronomical quadrant. In his Lectures of Natural and Experimental Philosophy George Adams (and subsequently William Jones) devotes six pages to the construction and use of the simple astronomical quadrant. But in a footnote, Jones describes this improved version: "By the addition of a small telescope, with a reflecting eye-piece, vernier scales to the arc and circle, rack-work and pinion to the arc AB, and circle EF, &c. I have rendered this small instrument useful for observing angles up to the zenith, and with more ease and accuracy for angles in general." The first example we have seen. (Featured in "Wondrous Devices" exhibition, Hudson River Museum, 2018) (9011) $9800.


Aluminum from the Columbian Exhibition Click on any image for a larger view.

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PERPETUAL CALENDAR MADE FOR THE COLUMBIAN EXHIBITION, American, 1892, signed "Perpetual Calendar, Patd. 1891 & 1892 by W.W. Kitchen." Made of aluminum, 1-3/16" (3 cm) in diameter, the disk bears on one side a raised profile of Christopher Columbus, and on the other a calendar marking every seventh day of each month. At the center is inset a brass volvelle with the days of the week. Setting this volvelle once per year allows direct readout of the day of the week for every date. This is a fine example of the perpetual calendar patented by William Whitney Kitchen, of Rockford, Illinois, on 1 December 1891. It was available at the 1893 World¹s Columbian Exposition held in Chicago to celebrate the quatercentenary of Columbus' 1492 voyage to the New World. (9052) $450.


Triplet Lenses Throughout Click on any image for a larger view.

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REMARKABLE COMPACT ALL-TRIPLE-LENS BINOCULARS, French, c. 1875, engraved "Douze Verres" (for "Twelve Lenses") and signed in the case "Gregoire Opticien, Quai St. Antoine, 14." Measuring 3-7/8" (10 cm) overall and 1-1/8" (3 cm) thick (closed), they are constructed of gilt brass and tortoiseshell, with a central knurled ivory focusing knob. Each objective lens, and each eyepiece, is itself a triplet, a sophisticated design to minimize aberrations and permit a compact, short-focal-length instrument. The apparent maker was Gregoire of Lyon, working throughout the third quarter 19th century. The firm had been founded in 1790, owned by Pierre Biette in the 1830's, and by H. Peter in the late 19th century. A fine device, in superb condition, with the original carrying case. (9030) $1350.


Lunar / Solar Calendar Disk Click on any image for a larger view.

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PERPETUAL CALENDAR / LUNAR CALENDAR, English, 19th century, made of brass 1-1/2" (3.7 cm) in diameter. One side has a rotating disk marked "Day of the Month For Ever," with a smiling sunface and a ring of month dates. This reads against a fixed ring of weekdays. The other side has a volvelle marked "Moon's Age, Phases, and Southings," with circular scales of twice-12 hours, date of the lunar month, and weekdays. An eccentric circle indicates fullness of the moon. In fine condition, this is an uncommon form of lunar / solar calendar. We note a variant version, undoubtedly by the same maker, marked as a tidal calendar "High Water and Moon¹s Age" (Tesseract Catalogue 38, item 58). (Featured in "Wondrous Devices" exhibition, Hudson River Museum, 2018) (8088) $750.


Innovative Telescope in Silver Plate Click on any image for a larger view.

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SPLENDID MINIATURE TELESCOPE WITH COMBINABLE EYE LENSES AND SOLAR CAP, English, c. last quarter 18th century, signed "J. Bleuler, London." Constructed with tubes and fittings of Sheffield silver plated copper and brass, this little telescope opens from 2-3/4" to 6" (7 - 15 cm) with three drawtubes. The main tube is finished with black enamel over copper. Giving erect images, the optics are a greenish triplet achromatic objective, two swiveling eyelenses useable singly or in combination, and a slip-on solar filter / dust cap. It is signed on the largest drawtube, and numbered 1, 2, 3 on the smallest. Condition is very fine noting a few scratches to the enamel. It is complete with the original cylindrical wood carrying case bound in red Morocco leather. The innovative maker of this unusual telescope was John Bleuler (1757 - 1829) of Ludgate Hill, apprenticed to Shuttleworth, made free in the Spectaclemakers Company in 1779. (8028) $2200.


Carl Zeiss circa 1930 Click on any image for a larger view.

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OFFICIAL CARL ZEISS PLANETARIUM PHOTOGRAPHS, German, c. 1930, the 14 original silver print photographs measuring 5" x 7" (13 x 18 cm), and variously bearing "Carl Zeiss, Jena" stamps, code number stamps, and/or applied printed descriptions. Depicted are planetaria, equipment, and activities. Most sites are in Germany; there are dramatic views of the powerful modernist architecture of the Weimar Republic applied to planetarium buildings. One unforgettable image shows Mussolini departing the Mailand (Milan) "Ulrico Hoepli" planetarium at its dedication on 20 May 1930. (8038) $1150.


Uncommon Globes from Chicago Click on any image for a larger view.

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AN AMERICAN GLOBE PAIR, c. 1910, each 10" (25 cm) diameter globe signed "Atlas School Supply Co., Chicago, Manufacturers of Globes." The terrestrial gores are color lithographed and dense with detail, and include isothermal lines, important undersea cables, and wireless communications. The celestial gores are printed in blue, with numerous stars with their astronomical letter and number identifications, and with the traditional constellation figures finely printed in pale bronze. Each globe is mounted in a bent wire semi-meridian, which is inserted into an 11-1/2" (29 cm) tall turned wood base with applied distinctive decor of winged torches (?) and sunflowers (?), gold painted throughout. Condition is good noting some browning to the paper, a couple of small scratches, and some flaking to the gold. Possibly of Masonic provenance, an interesting American globe pair. (7029) $2200.


Four-Eyepiece Telescope by Plossl Click on any image for a larger view.

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QUADRUPLE-EYEPIECE THREE-DRAW MONOCULAR, Austrian, early 19th century, signed "Plofsl in Wien." Opening from 3-1/4" to 8-1/4" (8 - 21 cm) and constructed of silver plated brass and copper, this small telescope is fitted with a cemented doublet achromatic objective, and a wheel of four selectable eye lenses. The tubes are rolled and soldered, not drawn. It offers upright images of high magnification but with a small field of view. Condition is fine noting negligible dents and a tiny edge chip to the lens. There is no handle or mount. The original shaped wood case is lined in purple silk and bound in red Morocco leather. Georg Simon Plossl (1794 - 1868) trained with the Voigtlander optical firm in Vienna, founding his own workshop in 1823. By 1845 he employed no less than 36 workers, and was famous for the quality of his microscopes and telescopes. (8078) $1900.



Prague-Centered Projection with Celestial Volvelle Click on any image for a larger view.

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THE URANOSCOPE OF PROFESSOR ADOLF MACH, Czech, c. early 20th century, signed "Uranoskop. Astronomicko-zemepisny ukazatel. Sestavil prof. Adolf Mach." Constructed on heavy card, 18-5/8" x 19-3/4" (47 x 50 cm), this unusual planisphere has a rotating volvelle of the heavens printed on starched linen, and a rotating brass index pointer, with readout against an outer hour scale divided every minute. Underneath the volvelle is a fixed map of the earth, printed in colors, utilizing a most remarkable projection centered on Prague. Condition is good with general light soiling and wear, and wrinkling to the linen. (8048) $950.





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