Photometria sive de mensura et gradibus luminis, colorum et umbrae

LAMBERT, Johann Heinrich

Published by Christoph Peter Detleffsen for the widow of Eberhard Klett, Augsburg, 1760

About this Item

"THE FOUNDATION OF THE SCIENCE OF PHOTOMETRY" (PMM 205) . First edition, very rare, and the finest copy we have seen, of the foundation work of photometry, the measurement of the intensity of light, both objectively and as perceived by the eye; this is one of the rarest of modern science books of this stature. Lambert's discoveries "are of fundamental importance in astronomy, photography and visual research generally . Both Kepler and Huygens had investigated the intensity of light, and the first photometer had been constructed by Pierre Bouguer (1698-1758); but the foundation of the science of photometry - the exact scientific measurement of light - was laid by Lambert's 'Photometry' . In the Photometria he described his photometer and propounded the law of the absorption of light named after him. He investigated the principles and properties of light, of light passing through transparent media, light reflected from opaque surfaces, physiological optics, the scattering of light passing through transparent media, the comparative luminosity of the heavenly bodies and the relative intensities of coloured lights and shadows" (PMM). "It is difficult to overstate how original most of Photometria was and how great was the advance Lambert made with it. He was the first to accurately identify most fundamental photometric concepts, to assemble them into a coherent system of photometric quantities, to define these quantities with a precision sufficient for mathematical statement, and to build from them a system of photometric principles . The behavior of point light sources had been understood since Kepler's time. Lambert was the first to correctly solve the problem posed by extended light sources. He was the first to state the cosine emanation law, which describes how a surface of perfect diffusion emits light, and to see the far-reaching consequences of this idea. Lambert spent one tenth of Photometria developing equations for the calculation of illumination at points and surfaces from luminous areas of various forms - equations that are now used in modern computer graphics, and thermal and lighting engineering . With his emanation law, Lambert calculated the average brightness of the moon and planets, anticipating part of modern astrophysics by a century . Lambert made extensive measurements of the photometric properties of materials by ingenious application of the process of equating two brightnesses. He determined the reflectance and transmittance of glass for a range of angles, the brightness of images produced by lenses, the diffuse reflectance of matte surfaces, and the absorption of light in glass and in the atmosphere. He measured the color composition of white and colored surfaces and was the first to mix colored light and record that the result was different from mixing colored pigments . Lambert was the first to attempt to establish a relationship between the subjective assessment of a luminous stimulus - the brightness - made by the visual system, and the strength - the luminance and size - of that stimulus" (Dilaura, pp. i-ii). ABPC/RBH record the sale of three copies since Norman. OCLC lists copies in US at Brown, Harvard Medical School and Oklahoma. Provenance: Georg Hermann Quincke (1834-1924) (signature on front free endpaper). Quincke received his Ph. D. in 1858 at Berlin, having previously studied also at Königsberg and at Heidelberg. He became privatdozent at Berlin in 1859, professor at Berlin in 1865, professor at Würzburg in 1872, and in 1875 was called to be professor of physics at Heidelberg, where he remained until his retirement in 1907. Quincke did important work in the experimental study of the reflection of light, especially from metallic surfaces. "Lambert began with two simple axioms: light travels in a straight line in a uniform medium and rays that cross do not interact. Like Kepler before him, he recognized that 'laws' of photometry are simply consequences and follow directly from these two assumptio. Seller Inventory # 5873

Bibliographic Details

Title: Photometria sive de mensura et gradibus ...

Publisher: Christoph Peter Detleffsen for the widow of Eberhard Klett, Augsburg

Publication Date: 1760

Edition: First edition.