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Tosca, Thomas Vicente
Tosca, Thomas Vicente
Tosca, Thomas Vicente
Tosca, Thomas Vicente
Tosca, Thomas Vicente

Tosca, Thomas Vicente

Libro de la Gnomonica...de los Reloxes de Sol

Manuscript, no place, no date but Valencia, before 1715

Small in quarto, 20,5x15,5 cm.

2 fly leaves; 3 nn leaves; 238 pages, continuously numbered; 14 nn leaves; 2 nn lvs. Contemporary limp vellum. Title in old manuscript on the spine: de RELOXES.

Paper in gatherings of 12 and 14 lvs. The watermark about 7x4 cm in the paper is constant: Eagle with two heads under a crown, carrying a coat of arms between its wings with the letters M and C. It is not in Briquet and similar watermarks tend to be older, mainly XVI century.

5 nn preliminary leaves:

The first blank

The second, Soy de Manuel Salvador Liter, 1842

The third, title in brown and red ink

The fourth, Horas en las principales regiones del mundo (moving parts).

The last, fifth, printed and colored image of San Vicente Ferer (patron of Valencia) and in verso a brief resume on the Rule of the golden ratio.

Main text:

Pp. 1-227: text in four parts, each with 10-20 chapters with many drawings and moving parts and two inserted leaves. End of last page: Finis

Loosely inserted:

An instrument that relates hours; days of the week, the months, the zodiac. The moving parts on vellum that are physically connected to the book relate the fullness of the moon; the month, the day and the hour with the height of the sun. It is very similar to the one Apianus included in his cosmography (first edition: 1524), but curiously turns against the clock!

An original watercolor, the portrait of Prof Diego de Torres Villaroel, facing right

Post scriptum:

Pp. 228-238: two additional texts one on the use of Astrolabe and another on the Height of the Polar star. Last leaf blank.

Between pp 226 and 227 a double leaf has been bound in: otra definicion y explicacion (de la esphera)

After the last blank is another gathering of 16 leaves. Seven of them have a drawing in brown ink of the outside border of (different) coat of arms sometimes with short text in it like sic transit gloria mundi and bible quotes.

Two of the seven central ovals are filled, one with an astrological text, the other with an astronomical instrument.

The text.

The text is written in one and the same hand, be it that additions to the central text may have been written at different times, but still by the same hand. The text is richly illustrated with about 150 fine drawings in ink in black and white and/or colors, three with moving parts and all in a very fine hand, complete and practically without errors or corrections.


In the first part , pp. 1-50, the mathematical basis for the relation between place and time are given: Tratado I en que .... With 25 drawings, one with a moving part (p.43) and 3 tables.

The second part, p 50-118, how to design a sun dial, horizontal or vertical without declination with 46 drawings and one inserted page size mobile of 3 levels on vellum. This mobile was connected to the book with a twisted thread.

The third part, pp 119-156, how to measure time in different sun dials complementing each other to cover a 24 hour day, including a manual on how to make a moon dial (pp 155 and 156) with 36 drawings and no tables.

The fourth and last part pp. 157- 227, has various topics like how to divide the Zodiac in degrees, how to fix the tropics, how to fix the hours, Italian, Babylonian, and finally how to actually make mobile sun dials (p 199 and further) with 41 drawings and 4 tables.

The textbook ends here. It is followed by two later short essays to connect the previous text with the science of navigation, the first on how to establish the meridian where you are without an astrolabium, pp 228-232, and the other on how to establish the height of the Polar star, pp 233-236.

€ 32000


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