1 books for « hauy l abbe rene jus... »Edit

‎Traité des Caractères physiques des Pierres Précieuses, pour servir a leur determination lorsqu'elles ont été taillées.‎

‎Paris, Courcier, 1817. Contemp. hcalf. Richly gilt spine. Tome-and titlelabels with gilt lettering. An old repair to spine at upper compartment. Some small cracks to leather at spine. Spine a bit rubbed. XVI,XXII,253 pp. and 3 large folded engraved plates with many figs. showing crystal forms and Nicholson's hydrometer. Some scattered brownspots, mainly at margins. A wide-margined copy.‎

‎Scarce first edition of Haüys landmark work on the crystallography of gemstones. Haüy had already in 1784 demonstrated the constancy of aspects of the geometric form of the individual crystals and hereby he laid the foundation stones of the science of Crystallography in general. In the offered work he applies his crystal-discoveries of the constancy of angles to the cutting of gems, thus providing us with the first handbook to show how to determine different kinds of gemstones, and he thereby also founded the science of Gemology. ""He hypothesized that each crystal was built up of successive additions of what we now call a ""unit cell"" to form - in the absence of external inteference - a simple geometric shape with constant angles and with sides trhat could be related by simple integral ratios. he maintained that an identity of difference in crystalline form implied an identity or difference in chemical composition. This was the beginning of the science of crystallograpy, which was to attain maturity over a century later with the development of X-ray techniques by Laue and Bragg.""(Asimov).‎