Both places, Bonnevoie and Hollerich, are now districts of Luxembourg City. Lippmann made several important contributions to various branches of physics over the years. One of Lippmann’s early discoveries was the relationship between electrical and capillary phenomena which allowed him to develop a mathematique Et Physique: Seminaire De L’Ecole Normale Superieure, 1979-1982 PDF capillary electrometer, subsequently known as the Lippmann electrometer which was used in the first ECG machine.
In a paper delivered to the Philosophical Society of Glasgow on 17 January 1883, John G. Lippmann’s electrometer consists of a tube of ordinary glass, 1 metre long and 7 millimetres in diameter, open at both ends, and kept in the vertical position by a stout support. The lower end is drawn into a capillary point, until the diameter of the capillary is . In 1881, Lippmann predicted the converse piezoelectric effect.
A colour photograph made by Lippmann in the 1890s. It contains no pigments or dyes of any kind. Above all, Lippmann is remembered as the inventor of a method for reproducing colours by photography, based on the interference phenomenon, which earned him the Nobel Prize in Physics for 1908. In 1886, Lippmann’s interest turned to a method of fixing the colours of the solar spectrum on a photographic plate. On 2 February 1891, he announced to the Academy of Sciences: « I have succeeded in obtaining the image of the spectrum with its colours on a photographic plate whereby the image remains fixed and can remain in daylight without deterioration. The interference phenomenon in optics occurs as a result of the wave propagation of light. Lippmann made use of this phenomenon by projecting an image onto a special photographic plate capable of recording detail smaller than the wavelengths of visible light.
The finished plate was illuminated from the front at a nearly perpendicular angle, using daylight or another source of white light containing the full range of wavelengths in the visible spectrum. At each point on the plate, light of approximately the same wavelength as the light which had generated the laminae was strongly reflected back toward the viewer. In practice, the Lippmann process was not easy to use. Extremely fine-grained high-resolution photographic emulsions are inherently much less light-sensitive than ordinary emulsions, so long exposure times were required. With a lens of large aperture and a very brightly sunlit subject, a camera exposure of less than one minute was sometimes possible, but exposures measured in minutes were typical. Lippmann’s process foreshadowed laser holography, which is also based on recording standing waves in a photographic medium. Denisyuk reflection holograms, often referred to as Lippmann-Bragg holograms, have similar laminar structures that preferentially reflect certain wavelengths.
In 1908, Lippmann introduced integral photography, in which a plane array of closely spaced small lenses is used to photograph a scene, recording images of the scene as it appears from many slightly different horizontal and vertical locations. When the resulting images are rectified and viewed through a similar array of lenses, a single integrated image, composed of small portions of all the images, is seen by each eye. In 1895, Lippmann evolved a method of eliminating the personal equation in measurements of time, using photographic registration, and he studied the eradication of irregularities of pendulum clocks, devising a method of comparing the times of oscillation of two pendulums of nearly equal period. Lippmann also invented the coelostat, an astronomical tool that compensated for the Earth’s rotation and allowed a region of the sky to be photographed without apparent movement. Lippmann was a member of the Academy of Sciences from 8 February 1886 until his death, serving as its President in 1912. Lippmann married the daughter of the novelist Victor Cherbuliez in 1888.