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Writing in Venice, in 1669, Domenico Martinelli says that marble dust, or river sand, or the powder which is used for glass cutting can be used for sand-glasses, but the filling which he rates most highly is that made from lead or tin The falling sands of time have given modern poets their favorite metaphor for the passing hours. In England, sand glasses were frequently placed in coffins as a symbol that life's time had run out. "The sands of time are sinking," went the hymn. "the dawn of heaven breaks." Just as in the case of the mechanical clock, we have no certain knowledge when, where or by whom, so called sand-glasses were invented. The Romans and Greeks had the necessary technical knowledge and skill in glass making, but there is no positive evidence of the existence of sand-glasses in those early days. It has been claimed that the Greeks used sand-glasses in the third century, B.C., but the evidence upon which this claim was based has now been discredited. The evidence was provided by a marble bas-relief, formerly part of an old Greek sarcophagus, which was built into the wall of the Palazzo Mattei in Rome when it was constructed in about 1613-1616. The bas-relief shows a mythological scene which may possibly represent the marriage of Peleus and thetis and there is a sand-glass among the various figures. Recent archaeological study has shown, however, that the lower part of the bas-relief, in which the sand-glass appears, is a restoration which was probably carried out when the palazzo Mattei was built.

hat is time? We sense the passage of time in our personal experience and observe it in the world around us. We feel, think, and act in the flow of time. Einstein said, "Space and time are modes by which we think, not conditions under which we live." Time--the time that we know through clocks and calendars--was invented. The measurement of time is an ancient science, though many of its discoveries are relatively recent. The Cro-Magnons recorded the phases of the Moon some 30,000 years ago--but the first minutes were counted accurately only 400 years ago, and the atomic clocks that allow us to track the approach of the millennium by the billionth of a second are less than 50 years old.

Seite weiterempfehlen | Drucken METAS - das nationale Metrologieinstitut Das Bundesamt für Metrologie (METAS) realisiert und vermittelt international abgestimmte und anerkannte Masseinheiten in der erforderlichen Genauigkeit. Es beaufsichtigt die Verwendung von Messmitteln in den Bereichen Handel, Verkehr, öffentliche Sicherheit, Gesundheit und Umwelt. METAS überwacht den Vollzug der gesetzlichen Bestimmungen durch die Kantone und die ermächtigten Eichstellen. Es stützt seine Tätigkeiten auf das Bundesgesetz über das Messwesen.

Napóra tervezése kivitelezése. Apáczai Csere János 1653-ben megjelent, a kor valamennyi tudományát rendszerező művében, a Magyar Encyclopaediaban"a csinálmányokról" szóló VIII-ik részben felsorol több tucattalálmányt, melyek nagyban elősegítették az emberek mindennapiboldogulását. Megemlíti többek között a számvető táblát, a puskaport, akemencét és nem utolsó sorban a napórát.

Gnomonika, A minőségi napórák készítője. Egyedi horizontális és vertikális napórák készítése természetes anyagokból (réz, kő, márvány, gránit, kovácsoltvas). Művészien megfestett vertikális napórák alkotása és restaurálása.