Description
Lava rock.
Lava is a liquid rock. After magma reaches the Earth's surface or the seabed, it is called lava. Due to differences in magma composition, flow rate, temperature, and chemical and mineralogical composition, there are several types of lava, each with its own unique behavior and characterized by a porous structure. Lava can have a destructive effect, but also a creative one. For example, new land can be formed from lava, which is how the Hawaiian Islands in the Pacific Ocean were formed. Furthermore, cooled lava—after several centuries of weathering—is very fertile and therefore suitable for agricultural use. The word "lava" originates in Italian and is likely derived from the Latin word labes, which refers to the sliding or shifting of lava. The word was first used in its current meaning by Francesco Serao, professor of medicine at the University of Naples, when he described the eruption of Vesuvius from May 14 to June 4, 1737. Serao believed lava was a mixture of sand and soil melted by the heat of volcanic fire. He described "a stream of fiery lava" compared to the water and mud that flow from a volcano after heavy rain. Cooling, viscous lava often accumulates in a volcanic shaft. This blockage, combined with the presence of gases in the lava, causes pressure to build up within the shaft. Eventually, an eruption occurs, producing large clouds of volcanic ash and gas, as well as pyroclastic flows. The most explosive eruptions are followed by a quieter period during which lava is expelled. If the lava is rich in silica, a slowly growing lava dome forms, a large, pillow-like structure full of cracks and fissures. The top and rims of a lava dome are usually covered with rock fragments, breccia, and ash. The hardened rock that forms from lava is called effusive rock. The appearance and composition of different effusive rocks vary greatly. If a rhyolite lava flow cools quickly, it can become obsidian. However, if it's filled with gas bubbles, it can also become pumice. If the same lava cools slowly, it becomes a light-colored, solid rock called simply rhyolite.
The Kama Sutra is considered the most important Indian textbook on the art of love. It was compiled by Vatsyayana, probably in the second century CE. It discusses in detail and in a didactic manner many topics of eroticism. The book was a guide for (newly) married couples to discover each other and to find pleasure in a time when arranged marriages could seriously disrupt romance. It teaches the man to please the woman he has married and thus win her love. The Buddha also taught a Kama Sutra, dated to the fourth century BC. It does not discuss how to obtain pleasure, but how the pursuit of sensual pleasure leads to both pleasure and unhappiness, and that one is therefore better off avoiding sensual pleasure and focusing on the search for Nirvana.
