Tar in the context of "Destructive distillation"

A ground is waxy material applied to the surface of a metal etching plate. A metal etching plate is a piece of sheet metal, usually copper, zinc, steel, or aluminium. The ground resists the acid or mordant which is used for etching, protecting areas of the metal plate. Grounds are made from a variety of materials including tar, asphaltum, paint (including spray paint), oil pastels, and other materials manufactured specifically for etching.

Most commonly, a ground is applied evenly over the surface of the metal sheet (also known as the etching plate), and then removed using scratching and other mark making techniques to reveal bare metal underneath. In the traditional technique this is done with a metal needle. However, different grounds enable the artist to create different types of marks. Some types of grounds, such as an aquatint ground, are more complex and may not include a removal process because they are applied in a selective manner.

Pitch is a viscoelastic polymer which can be natural or manufactured, derived from petroleum, coal tar, or plants. Pitch produced from petroleum may be called bitumen or asphalt, while plant-derived pitch, a resin, is known as rosin in its solid form. Tar is sometimes used interchangeably with pitch, but generally refers to a more liquid substance derived from coal production, including coal tar, or from plants, as in pine tar.

Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges alone are estimated to account for 75% of the magma output on Earth. Although most submarine volcanoes are located in the depths of seas and oceans, some also exist in shallow water, and these can discharge material into the atmosphere during an eruption. The total number of submarine volcanoes is estimated to be over one million (most are now extinct) of which some 75,000 rise more than 1 kilometre (0.62 miles) above the seabed. Only 119 submarine volcanoes in Earth's oceans and seas are known to have erupted during the last 11,700 years.

Hydrothermal vents, sites of abundant biological activity, are commonly found near submarine volcanoes.

Petroleum products are materials derived from crude oil (petroleum) as it is processed in oil refineries. Unlike petrochemicals, which are a collection of well-defined usually pure organic compounds, petroleum products are complex mixtures. Most petroleum is converted into petroleum products, which include several classes of fuels.

According to the composition of the crude oil and depending on the demands of the market, refineries can produce different shares of petroleum products. The largest share of oil products is used as "energy carriers", i.e. various grades of fuel oil and gasoline. These fuels include or can be blended to give gasoline, jet fuel, diesel fuel, heating oil, and heavier fuel oils. Heavier (less volatile) fractions can also be used to produce asphalt, tar, paraffin wax, lubricating and other heavy oils. Refineries also produce other chemicals, some of which are used in chemical processes to produce plastics and other useful materials. Since petroleum often contains a few percent sulfur-containing molecules, elemental sulfur is also often produced as a petroleum product. Carbon, in the form of petroleum coke, and hydrogen may also be produced as petroleum products. The hydrogen produced is often used as an intermediate product for other oil refinery processes such as hydrocracking and hydrodesulfurization.

The American System was an economic plan that played an important role in American policy during the first half of the 19th century, rooted in the "American School" ideas and of the Hamiltonian economic program of Alexander Hamilton.

A plan to strengthen and unify the nation, the American System was advanced by the Whig Party and a number of leading politicians including Henry Clay and John Quincy Adams. Clay was the first to refer to it as the "American System". Motivated by a growing American economy bolstered with major exports such as cotton, tobacco, native sod, and tar, the politicians sought to create a structure for expanding trade. This System included such policies as:

Tarmacadam or tarmac is a concrete road surfacing material made by combining tar and macadam (crushed stone and sand), patented by Welsh inventor Edgar Purnell Hooley in 1902. It is a more durable and dust-free enhancement of simple compacted stone macadam surfaces invented by Scottish engineer John Loudon McAdam in the early 19th century. The terms "tarmacadam" and "tarmac" are also used for a variety of other materials, including tar-grouted macadam, bituminous surface treatments and modern asphalt concrete.

Savaiʻi is the largest and highest island both in Samoa and in the Samoan Islands chain. The island is also the sixth largest in Polynesia, behind the three main islands of New Zealand and the Hawaiian Islands of Hawaii and Maui. While it is larger than the second main island, Upolu, it is significantly less populated.

Samoans sometimes refer to the island of Savaiʻi as Salafai: This is its classical Samoan name, and is used in formal oratory and prose. The island is home to 43,958 people (2016 census), and they make up 24% of the population of Samoa.The island's only township and ferry terminal is called Salelologa. It is the main point of entry to the island, and is situated at the east end of Savaiʻi. A tar sealed road serves as the single main highway, connecting most of the villages. Local bus routes also operate, reaching most settlements.

Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and tarmac, bitmac or bitumen macadam in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the nineteenth century. It consists of mineral aggregate bound together with bitumen (a substance also independently known as asphalt, pitch, or tar), laid in layers, and compacted.

The American English terms asphalt (or asphaltic) concrete, bituminous asphalt concrete, and bituminous mixture are typically used only in engineering and construction documents, which define concrete as any composite material composed of mineral aggregate adhered with a binder. The abbreviation, AC, is sometimes used for asphalt concrete but can also denote asphalt content or asphalt cement, referring to the liquid asphalt portion of the composite material.

A composition roller is a tool used in letterpress printing to apply ink to a bed of type in a printing press. It consists of a cylinder made of a substance known as "roller composition" or simply "composition", a mixture of hide glue and sugar (in the form of molasses or treacle), with various additives such as glycerin depending on the particular recipe. Early recipes also included gypsum plaster and tar, though these were eventually found unnecessary.

Before its invention, most inking of printing presses was done by manually pounding the type with ink balls, specially treated leather balls stuffed with wool. The difficulty and time involved in making and using ink balls led to various attempts to use cylinders, which could be rolled rather than pounded. Leather rollers (or "skin rollers") were attempted, and were used on the earliest steam-powered cylinder presses, yet these did not work as well as the ink balls, and the stitching seam would appear on the printed type.