Details
SNEL, Willebrord (1580-1626). Eratosthenes batavus, de terrae ambitus vera quantitate. Leiden: Jodocus Colster, 1617.
4o (193 x 139 mm). Full-page engraving showing the triangulation of Holland on p. 168, numerous woodcut diagrams in text. Contemporary blind-ruled Dutch vellum (a few very minor marginal defects).
FIRST EDITION OF SNEL'S FUNDAMENTAL WORK IN THE SCIENCE OF GEODESY. In this work Snel laid down the principles of a new method for determining the length of the arc of the meridian by triangulation. "In 1615 he became deeply involved in the determination of the length of the meridian, selecting for this work the method of triangulation, first proposed by Gemma Frisius in 1533 and also used by Tycho. Snel developed it to such an extent that he may rightfully be called the father of triangulation. Starting with his house ... he used the spires of town churches as points of reference. Thus, through a net of triangles, he computed the distance from Alkmaar to Bergen-op-Zoom (around 130 kilometers). The two towns lie on approximately the same meridian. Snel used the distance from Leiden to Zoeterwoude (about 5 kilometers) as a baseline. His instruments were made by Blaeu" (DSB). From the mean of these two measurements Snel calculated the length of a degree to be 352,347 feet, a more accurate reckoning than any previous attempt. Snel also solved the so-called recession problem for three points, and the problem is often named after him. The title of this work is a tribute to the Greek mathematician Eratosthenes, who was famous for his measurement of the circumference of the earth. VERY FINE COPY. Norman 1963.
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FIRST EDITION OF SNEL'S FUNDAMENTAL WORK IN THE SCIENCE OF GEODESY. In this work Snel laid down the principles of a new method for determining the length of the arc of the meridian by triangulation. "In 1615 he became deeply involved in the determination of the length of the meridian, selecting for this work the method of triangulation, first proposed by Gemma Frisius in 1533 and also used by Tycho. Snel developed it to such an extent that he may rightfully be called the father of triangulation. Starting with his house ... he used the spires of town churches as points of reference. Thus, through a net of triangles, he computed the distance from Alkmaar to Bergen-op-Zoom (around 130 kilometers). The two towns lie on approximately the same meridian. Snel used the distance from Leiden to Zoeterwoude (about 5 kilometers) as a baseline. His instruments were made by Blaeu" (DSB). From the mean of these two measurements Snel calculated the length of a degree to be 352,347 feet, a more accurate reckoning than any previous attempt. Snel also solved the so-called recession problem for three points, and the problem is often named after him. The title of this work is a tribute to the Greek mathematician Eratosthenes, who was famous for his measurement of the circumference of the earth. VERY FINE COPY. Norman 1963.