Solera by the producers of sherry. In a Spanish sherry "solera", the vintner may transfer about a third of each barrel a year. A solera sherry has to be at least three years old when bottled. A quite similar process is called sostrera, used to produce fortified wines in the Mediterranean regions of France. In Sicily, where Marsala wine is made, the system is called "in perpetuum". Solera vinification is used in the making of Mavrodafni ("Black Laurel"), a fortified red dessert wine made in the Northern Peloponnese in Greece. Exceptional "Mavrodafni" vintages are released every 20 or 30 years: they
An Experimental Enquiry Concerning the Source of the Heat which is Excited by Friction expense of caloric. An Experimental Enquiry Concerning the Source of the Heat which is Excited by Friction "An Experimental Enquiry Concerning the Source of the Heat which is Excited by Friction" (1798), which was published in the "Philosophical Transactions of the Royal Society", is a scientific paper by Benjamin Thompson, Count Rumford that provided a substantial challenge to established theories of heat and began the 19th century revolution in thermodynamics. Rumford was an opponent of the caloric theory of heat which held that heat was a fluid that could be neither created nor destroyed. He had further developed the view