manor's distillery. There were failed attempts to use graptolitic argillite as fertilizer in the 19th century. In the beginning of the 20th century, geologist and engineer Carl August von Mickwitz studied self-ignition of graptolitic argillite near Paldiski. At the University of Tartu oil shale geology and chemistry analyses were conducted during the 19th century by Georg Paul Alexander Petzholdt, Alexander Gustav von Schrenk, and Carl Ernst Heinrich Schmidt, among others. Beginning of oil shale industry Analysis of Estonian oil shale resources and mining possibilities intensified during the early 20th century while Estonia was part of the Russian Empire. Industrial development was under way in Saint Petersburg (known as Petrograd in 1914–24), but regional fuel resources were in short supply. A large shale oil extraction plant for processing Estonian oil shale was proposed in 1910. The outbreak of World War I, coupled with a fuel supply crisis, accelerated the pace of the research. In June 1916, the Russian geologist Nikolay Pogrebov oversaw mining of the first tonnes of oil shale at Pavandu and delivered it to Saint Petersburg (then Petrograd) Polytechnic Institute for large-scale experiments. These events marking the beginning of the Estonian oil shale industry took place more than half a century after an oil shale industry had emerged in Scotland, the leading oil shale industry in 1916, and a decade before the industry emerged in China, which, besides Estonia, is today the other leading oil shale-exploiting country. In 1916 a total of 640–690 tonnes of oil shale were sent to Saint Petersburg for testing. The tests proved that the oil shale was suitable for combustion as a solid fuel and for extraction of oil shale gas and shale oil. Based on these promising results, a plan for oil shale mining in Estonia was presented to the Emperor Nicholas II on 3 January 1917. On 13 February 1917, the Council of Ministers of Russia allocated 1.2 million rubles to purchase land and start mining activities. After the February Revolution, the Russian Provisional Government appointed a special commissioner for oil shale purchasing and stockpiling who began preliminary work for the digging of an oil shale mine at Pavandu, with full-scale construction carried out by about 500 workers, including war prisoners, in the summer of 1917. After the October Revolution, financing ceased and construction stopped. Two private Saint Petersburg firms, established specially for oil shale mining, Böckel & Co. and Mutschnik &