Before the development of the photographic camera, it had been known for hundreds of years that some substances, such as silver salts, darkened when exposed to sunlight. In a series of experiments, published in 1727, the German scientist Johann Heinrich Schulze demonstrated that the darkening of the salts was due to light alone, and not influenced by heat or exposure to air.
The 1727 Tabriz earthquake occurred on 18 November with an epicenter near Tabriz in northwest Iran. The maximum felt intensity was VIII (Severe) on the Mercalli intensity scale, and there were an estimated 77,000 deaths. The only record for this earthquake comes from an account written in 1821 and it is very likely that the information for this earthquake refers instead to the 1721 Tabriz earthquake.
The 1727 Tabriz earthquake occurred on 18 November with an epicenter near Tabriz in northwest Iran. The maximum felt intensity was VIII (Severe) on the Mercalli intensity scale, and there were an estimated 77,000 deaths.