A lake is an area of variable size filled with water, localized in a basin, that is surrounded by land, apart from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, and therefore are distinct from lagoons, Lakes can be contrasted with rivers or streams, which are usually flowing. Most lakes are fed and drained by rivers and streams, natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Other lakes are found in endorheic basins or along the courses of mature rivers, in some parts of the world there are many lakes because of chaotic drainage patterns left over from the last Ice Age. All lakes are temporary over geologic time scales, as they will fill in with sediments or spill out of the basin containing them. The word lake comes from Middle English lake, from Old English lacu, from Proto-Germanic *lakō, cognates include Dutch laak, Middle Low German lāke as in, de, Moorlake, de, Wolfslake, de, German Lache, and Icelandic lækur.
Also related are the English words leak and leach, none of these definitions completely excludes ponds and all are difficult to measure. For this reason, simple size-based definitions are used to separate ponds. One definition of lake is a body of water of 2 hectares or more in area, others have defined lakes as waterbodies of 5 hectares and above, or 8 hectares and above. Charles Elton, one of the founders of ecology, regarded lakes as waterbodies of 40 hectares or more. The term lake is used to describe a feature such as Lake Eyre. In common usage, many bear names ending with the word pond. One textbook illustrates this point with the following, In Newfoundland, for example, almost every lake is called a pond, whereas in Wisconsin, the majority of lakes on Earth are fresh water, and most lie in the Northern Hemisphere at higher latitudes. Canada, with a drainage system has an estimated 31,752 lakes larger than 3 square kilometres and an unknown total number of lakes. Finland has 187,888 lakes 500 square metres or larger, most lakes have at least one natural outflow in the form of a river or stream, which maintain a lakes average level by allowing the drainage of excess water.
Some lakes do not have an outflow and lose water solely by evaporation or underground seepage or both. Many lakes are artificial and are constructed for power generation, aesthetic purposes, recreational purposes, industrial use. Globally, lakes are greatly outnumbered by ponds, of an estimated 304 million standing water bodies worldwide, 91% are 1 hectare or less in area
A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, the sea is the system of Earths salty. The sea moderates Earths climate and has important roles in the cycle, carbon cycle. Although the sea has been traveled and explored since prehistory, the scientific study of the sea—oceanography—dates broadly to the British Challenger expedition of the 1870s. Owing to the present state of continental drift, the Northern Hemisphere is now equally divided between land and sea but the South is overwhelmingly oceanic. Salinity in the ocean is generally in a narrow band around 3. 5% by mass, although this can vary in more landlocked waters, near the mouths of large rivers. About 85% of the solids in the sea are sodium chloride. Deep-sea currents are produced by differences in salinity and temperature, surface currents are formed by the friction of waves produced by the wind and by tides, the changes in local sea level produced by the gravity of the Moon and Sun.
The direction of all of these is governed by surface and submarine land masses, former changes in sea levels have left continental shelves, shallow areas in the sea close to land. The most diverse areas surround great tropical coral reefs, whaling in the deep sea was once common but whales dwindling numbers prompted international conservation efforts and finally a moratorium on most commercial hunting. Life may have started there and aquatic microbial mats are generally credited with the oxygenation of Earths atmosphere, the sea is an essential aspect of human trade, mineral extraction, and power generation. It is the scene of activities including swimming, surfing. However, population growth, industrialization, and intensive farming have all contributed to marine pollution. Atmospheric carbon dioxide is being absorbed in increasing amounts, lowering its pH in a known as ocean acidification. The shared nature of the sea has made overfishing an increasing problem, both senses of sea date to Old English, the larger sense has required a definite article since Early Middle English.
Seas are generally larger than lakes and contain salt water, while the defining elements of size and being bounded are generally used, there is no formally accepted technical definition of sea among oceanographers. In international law, the United Nations Convention on the Law of the Sea states that all the ocean is the sea. Earth is the known planet with seas of liquid water on its surface, although Mars possesses ice caps
Irrigation is the method in which a controlled amount of water is supplied to plants at regular intervals for agriculture. It is used to assist in the growing of crops, maintenance of landscapes. Additionally, irrigation has a few uses in crop production. In contrast, agriculture that only on direct rainfall is referred to as rain-fed or dry land farming. Irrigation systems are used for dust suppression, disposal of sewage. Irrigation is often studied together with drainage, which is the natural or artificial removal of surface and sub-surface water from a given area, Irrigation has been a central feature of agriculture for over 5,000 years and is the product of many cultures. Historically, it was the basis for economies and societies across the globe, archaeological investigation has found evidence of irrigation where the natural rainfall was insufficient to support crops for rainfed agriculture. Ancient Egyptians practiced Basin irrigation using the flooding of the Nile to inundate land plots which had surrounded by dykes.
The flood water was held until the sediment had settled before the surplus was returned to the watercourse. The Ancient Nubians developed a form of irrigation by using a device called a sakia. Irrigation began in Nubia some time between the third and second millennium BCE and it largely depended upon the flood waters that would flow through the Nile River and other rivers in what is now the Sudan. In sub-Saharan Africa irrigation reached the Niger River region cultures and civilizations by the first or second millennium BCE and was based on wet season flooding, terrace irrigation is evidenced in pre-Columbian America, early Syria and China. These canals are the earliest record of irrigation in the New World, traces of a canal possibly dating from the 5th millennium BCE were found under the 4th millennium canal. Large scale agriculture was practiced and a network of canals was used for the purpose of irrigation. Ancient Persia as far back as the 6th millennium BCE, where barley was grown in areas where the rainfall was insufficient to support such a crop.
The Qanats, developed in ancient Persia in about 800 BCE, are among the oldest known irrigation methods still in use today and they are now found in Asia, the Middle East and North Africa. The system comprises a network of wells and gently sloping tunnels driven into the sides of cliffs. The noria, a wheel with clay pots around the rim powered by the flow of the stream, was first brought into use at about this time
Gas is one of the four fundamental states of matter. A pure gas may be made up of atoms, elemental molecules made from one type of atom. A gas mixture would contain a variety of pure gases much like the air, what distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer, the interaction of gas particles in the presence of electric and gravitational fields are considered negligible as indicated by the constant velocity vectors in the image. One type of commonly known gas is steam, the gaseous state of matter is found between the liquid and plasma states, the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention, high-density atomic gases super cooled to incredibly low temperatures are classified by their statistical behavior as either a Bose gas or a Fermi gas.
For a comprehensive listing of these states of matter see list of states of matter. The only chemical elements which are stable multi atom homonuclear molecules at temperature and pressure, are hydrogen and oxygen. These gases, when grouped together with the noble gases. Alternatively they are known as molecular gases to distinguish them from molecules that are chemical compounds. The word gas is a neologism first used by the early 17th-century Flemish chemist J. B. van Helmont, according to Paracelsuss terminology, chaos meant something like ultra-rarefied water. An alternative story is that Van Helmonts word is corrupted from gahst and these four characteristics were repeatedly observed by scientists such as Robert Boyle, Jacques Charles, John Dalton, Joseph Gay-Lussac and Amedeo Avogadro for a variety of gases in various settings. Their detailed studies ultimately led to a relationship among these properties expressed by the ideal gas law. Gas particles are separated from one another, and consequently have weaker intermolecular bonds than liquids or solids.
These intermolecular forces result from interactions between gas particles. Like-charged areas of different gas particles repel, while oppositely charged regions of different gas particles attract one another, randomly induced charges exist across non-polar covalent bonds of molecules and electrostatic interactions caused by them are referred to as Van der Waals forces. The interaction of these forces varies within a substance which determines many of the physical properties unique to each gas. A comparison of boiling points for compounds formed by ionic and covalent bonds leads us to this conclusion, the drifting smoke particles in the image provides some insight into low pressure gas behavior
A water clock or clepsydra is any timepiece in which time is measured by the regulated flow of liquid into or out from a vessel where the amount is measured. Water clocks, along with sundials and hourglasses, are likely to be the oldest time-measuring instruments, with the exceptions being the vertical gnomon. Where and when they were first invented is not known, the bowl-shaped outflow is the simplest form of a water clock and is known to have existed in Babylon and in Egypt around the 16th century BCE. Other regions of the world, including India and China, have evidence of water clocks. Some authors, claim that water clocks appeared in China as early as 4000 BCE, some modern timepieces are called water clocks but work differently from the ancient ones. Independently, the Chinese developed their own advanced water clocks, incorporating gears, escapement mechanisms, some water clock designs were developed independently and some knowledge was transferred through the spread of trade. These early water clocks were calibrated with a sundial, a water clock uses a flow of water to measure time.
If viscosity is neglected, the physical principle required to study such clocks is Torricellis law, there are two types of water clocks and outflow. In an outflow water clock, a container is filled with water, and this container has markings that are used to show the passage of time. As the water leaves the container, an observer can see where the water is level with the lines, an inflow water clock works in basically the same way, except instead of flowing out of the container, the water is filling up the marked container. As the container fills, the observer can see where the water meets the lines, according to Callisthenes, the Persians were using water clocks in 328 BC to ensure a just and exact distribution of water from qanats to their shareholders for agricultural irrigation. The use of clocks in Iran, especially in Zibad. Later they were used to determine the exact holy days of pre-Islamic religions, such as the Nowruz, Chelah, or Yaldā - the shortest, longest. The water clocks used in Iran were one of the most practical ancient tools for timing the yearly calendar, -Persian water clocks were a practical and useful tool for the qanats shareholders to calculate the length of time they could divert water to their farm.
The qanat was the water source for agriculture and irrigation so a just. The Fenjaan consisted of a pot full of water and a bowl with a small hole in the center. When the bowl became full of water, it would sink into the pot, and he would record the number of times the bowl sank by putting small stones into a jar. The place where the clock was situated, and its managers, were known as khaneh Fenjaan
Hydraulic machines are machinery and tools that use liquid fluid power to do simple work. Heavy equipment is a common example, in this type of machine, hydraulic fluid is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders and becomes pressurised according to the resistance present. The fluid is controlled directly or automatically by control valves and distributed through hoses and tubes, hydraulic machinery is operated by the use of hydraulics, where a liquid is the powering medium. In normal cases, hydraulic ratios are combined with a force or torque ratio for optimum machine designs such as boom movements. Examples Two hydraulic cylinders interconnected Cylinder C1 is one inch in radius, if the force exerted on C1 is 10 lbf, the force exerted by C2 is 1000 lbf because C2 is a hundred times larger in area as C1. The downside to this is that you have to move C1 a hundred inches to move C2 one inch, the most common use for this is the classical hydraulic jack where a pumping cylinder with a small diameter is connected to the lifting cylinder with a large diameter.
This combination is actually the same type of force multiplication as the cylinder example just that the force in this case is a rotary force. Both these examples are referred to as a hydraulic transmission or hydrostatic transmission involving a certain hydraulic gear ratio. For the hydraulic fluid to do work, it must flow to the actuator and/or motors, the fluid is filtered and re-pumped. The path taken by hydraulic fluid is called a hydraulic circuit of which there are several types, open center circuits use pumps which supply a continuous flow. Otherwise, if the valve is actuated it routes fluid to and from an actuator. The fluids pressure will rise to meet any resistance, since the pump has a constant output, if the pressure rises too high, fluid returns to tank through a pressure relief valve. Multiple control valves may be stacked in series and this type of circuit can use inexpensive, constant displacement pumps. Closed center circuits supply full pressure to the valves, whether any valves are actuated or not.
The pumps vary their flow rate, pumping very little hydraulic fluid until the operator actuates a valve, the valves spool therefore doesnt need an open center return path to tank. Multiple valves can be connected in an arrangement and system pressure is equal for all valves. The closed center circuits exist in two configurations, normally related to the regulator for the variable pump that supplies the oil, Constant pressure systems. Pump pressure always equals the pressure setting for the pump regulator and this setting must cover the maximum required load pressure
In the Iron Age, it was controlled by the Neo-Assyrian and Neo-Babylonian Empires. The Sumerians and Akkadians dominated Mesopotamia from the beginning of history to the fall of Babylon in 539 BC. It fell to Alexander the Great in 332 BC, and after his death, around 150 BC, Mesopotamia was under the control of the Parthian Empire. Mesopotamia became a battleground between the Romans and Parthians, with parts of Mesopotamia coming under ephemeral Roman control. In AD226, eastern part of it fell to the Sassanid Persians, division of Mesopotamia between Roman and Sassanid Empires lasted until the 7th century Muslim conquest of Persia of the Sasanian Empire and Muslim conquest of the Levant from Byzantines. A number of primarily neo-Assyrian and Christian native Mesopotamian states existed between the 1st century BC and 3rd century AD, including Adiabene and Hatra, Mesopotamia is the site of the earliest developments of the Neolithic Revolution from around 10,000 BC. The regional toponym Mesopotamia comes from the ancient Greek root words μέσος middle and ποταμός river and it is used throughout the Greek Septuagint to translate the Hebrew equivalent Naharaim.
In the Anabasis, Mesopotamia was used to designate the land east of the Euphrates in north Syria, the Aramaic term biritum/birit narim corresponded to a similar geographical concept. The neighbouring steppes to the west of the Euphrates and the part of the Zagros Mountains are often included under the wider term Mesopotamia. A further distinction is made between Northern or Upper Mesopotamia and Southern or Lower Mesopotamia. Upper Mesopotamia, known as the Jazira, is the area between the Euphrates and the Tigris from their sources down to Baghdad, Lower Mesopotamia is the area from Baghdad to the Persian Gulf and includes Kuwait and parts of western Iran. In modern academic usage, the term Mesopotamia often has a chronological connotation and it is usually used to designate the area until the Muslim conquests, with names like Syria and Iraq being used to describe the region after that date. It has been argued that these euphemisms are Eurocentric terms attributed to the region in the midst of various 19th-century Western encroachments, Mesopotamia encompasses the land between the Euphrates and Tigris rivers, both of which have their headwaters in the Armenian Highlands.
Both rivers are fed by tributaries, and the entire river system drains a vast mountainous region. Overland routes in Mesopotamia usually follow the Euphrates because the banks of the Tigris are frequently steep and difficult. The climate of the region is semi-arid with a vast desert expanse in the north which gives way to a 15,000 square kilometres region of marshes, mud flats, in the extreme south, the Euphrates and the Tigris unite and empty into the Persian Gulf. In the marshlands to the south of the area, a complex water-borne fishing culture has existed since prehistoric times, periodic breakdowns in the cultural system have occurred for a number of reasons. Alternatively, military vulnerability to invasion from marginal hill tribes or nomadic pastoralists has led to periods of trade collapse and these trends have continued to the present day in Iraq
Cast iron is a group of iron-carbon alloys with a carbon content greater than 2%. Its usefulness derives from its low melting temperature. Carbon ranging from 1. 8–4 wt%, and silicon 1–3 wt% are the main alloying elements of cast iron, Iron alloys with less carbon content are known as steel. While this technically makes the Fe–C–Si system ternary, the principle of cast iron solidification can be understood from the simpler binary iron–carbon phase diagram, cast iron tends to be brittle, except for malleable cast irons. It is resistant to destruction and weakening by oxidation, the earliest cast iron artefacts date to the 5th century BC, and were discovered by archaeologists in what is now Jiangsu in China. Cast iron was used in ancient China for warfare, during the 15th century, cast iron became utilized for artillery in Burgundy, and in England during the Reformation. The first cast iron bridge was built during the 1770s by Abraham Darby III, cast iron is used in the construction of buildings.
Cast iron is made by re-melting pig iron, often along with quantities of iron, limestone, carbon. Phosphorus and sulfur may be burnt out of the iron, but this burns out the carbon. Depending on the application and silicon content are adjusted to the desired levels, other elements are added to the melt before the final form is produced by casting. Cast iron is melted in a special type of blast furnace known as a cupola. After melting is complete, the molten cast iron is poured into a furnace or ladle. Cast irons properties are changed by adding various alloying elements, or alloyants, next to carbon, silicon is the most important alloyant because it forces carbon out of solution. A low percentage of silicon allows carbon to remain in solution forming iron carbide, a high percentage of silicon forces carbon out of solution forming graphite and the production of grey cast iron. Other alloying agents, chromium, molybdenum and vanadium counteracts silicon, promotes the retention of carbon and copper increase strength, and machinability, but do not change the amount of graphite formed.
The carbon in the form of graphite results in an iron, reduces shrinkage, lowers strength. Sulfur, largely a contaminant when present, forms iron sulfide, the problem with sulfur is that it makes molten cast iron viscous, which causes defects. To counter the effects of sulfur, manganese is added because the two form into manganese sulfide instead of iron sulfide, the manganese sulfide is lighter than the melt so it tends to float out of the melt and into the slag
Canals and navigations are human-made channels for water conveyance, or to service water transport vehicles. In the vernacular, both are referred to as canals, and in most cases, the works will have a series of dams. These areas are referred to as water levels, often just called levels. In contrast, a canal cuts across a drainage divide atop a ridge, many canals have been built at elevations towering over valleys and others water ways crossing far below. Cities need a lot of water and many canals with sources of water at a higher level can deliver water to a destination where there is a lack of water. The Roman Empires Aqueducts were such water supply canals, a navigation is a series of channels that run roughly parallel to the valley and stream bed of an unimproved river. A navigation always shares the drainage basin of the river, a vessel uses the calm parts of the river itself as well as improvements, traversing the same changes in height. A true canal is a channel that cuts across a drainage divide, most commercially important canals of the first half of the 19th century were a little of each, using rivers in long stretches, and divide crossing canals in others.
This is true for many canals still in use, there are two broad types of canal, Waterways and navigations used for carrying vessels transporting goods and people. These can be subdivided into two kinds, Those connecting existing lakes, other canals or seas and oceans and those connected in a city network, such as the Canal Grande and others of Venice Italy, the gracht of Amsterdam, and the waterways of Bangkok. Aqueducts, water canals that are used for the conveyance and delivery of potable water for human consumption, municipal uses, hydro power canals. Historically canals were of importance to commerce and the development, growth. In 1855 the Lehigh Canal carried over 1.2 million tons of burning anthracite coal, by the 1930s the company which built. By the early 1880s, canals which had little ability to compete with rail transport, were off the map. In the next couple of decades, coal was diminished as the heating fuel of choice by oil. Later, after World War I when motor-trucks came into their own, Canals are built in one of three ways, or a combination of the three, depending on available water and available path, Human made streams A canal can be created where no stream presently exists.
Either the body of the canal is dug or the sides of the canal are created by making dykes or levees by piling dirt, the water for the canal must be provided from an external source, like streams or reservoirs. Where the new waterway must change elevation engineering works like locks, lifts or elevators are constructed to raise, examples include canals that connect valleys over a higher body of land, like Canal du Midi, Canal de Briare and the Panama Canal
Water is a transparent and nearly colorless chemical substance that is the main constituent of Earths streams and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen, Water strictly refers to the liquid state of that substance, that prevails at standard ambient temperature and pressure, but it often refers to its solid state or its gaseous state. It occurs in nature as snow, ice packs and icebergs, fog, aquifers, Water covers 71% of the Earths surface. It is vital for all forms of life. Only 2. 5% of this water is freshwater, and 98. 8% of that water is in ice and groundwater. Less than 0. 3% of all freshwater is in rivers and the atmosphere, a greater quantity of water is found in the earths interior. Water on Earth moves continually through the cycle of evaporation and transpiration, precipitation. Evaporation and transpiration contribute to the precipitation over land, large amounts of water are chemically combined or adsorbed in hydrated minerals.
Safe drinking water is essential to humans and other even though it provides no calories or organic nutrients. There is a correlation between access to safe water and gross domestic product per capita. However, some observers have estimated that by 2025 more than half of the population will be facing water-based vulnerability. A report, issued in November 2009, suggests that by 2030, in developing regions of the world. Water plays an important role in the world economy, approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a source of food for many parts of the world. Much of long-distance trade of commodities and manufactured products is transported by boats through seas, lakes, large quantities of water and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a variety of chemical substances, as such it is widely used in industrial processes. Water is central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, sport fishing, Water is a liquid at the temperatures and pressures that are most adequate for life.
Specifically, at atmospheric pressure of 1 bar, water is a liquid between the temperatures of 273.15 K and 373.15 K
The term Engineering is derived from the Latin ingenium, meaning cleverness and ingeniare, meaning to contrive, devise. Engineering has existed since ancient times as humans devised fundamental inventions such as the wedge, wheel, each of these inventions is essentially consistent with the modern definition of engineering. The term engineering is derived from the engineer, which itself dates back to 1390 when an engineer originally referred to a constructor of military engines. In this context, now obsolete, a referred to a military machine. Notable examples of the obsolete usage which have survived to the present day are military engineering corps, the word engine itself is of even older origin, ultimately deriving from the Latin ingenium, meaning innate quality, especially mental power, hence a clever invention. The earliest civil engineer known by name is Imhotep, as one of the officials of the Pharaoh, Djosèr, he probably designed and supervised the construction of the Pyramid of Djoser at Saqqara in Egypt around 2630–2611 BC.
Ancient Greece developed machines in both civilian and military domains, the Antikythera mechanism, the first known mechanical computer, and the mechanical inventions of Archimedes are examples of early mechanical engineering. In the Middle Ages, the trebuchet was developed, the first steam engine was built in 1698 by Thomas Savery. The development of this gave rise to the Industrial Revolution in the coming decades. With the rise of engineering as a profession in the 18th century, similarly, in addition to military and civil engineering, the fields known as the mechanic arts became incorporated into engineering. The inventions of Thomas Newcomen and the Scottish engineer James Watt gave rise to mechanical engineering. The development of specialized machines and machine tools during the revolution led to the rapid growth of mechanical engineering both in its birthplace Britain and abroad. John Smeaton was the first self-proclaimed civil engineer and is regarded as the father of civil engineering.
He was an English civil engineer responsible for the design of bridges, harbours and he was a capable mechanical engineer and an eminent physicist. Smeaton designed the third Eddystone Lighthouse where he pioneered the use of hydraulic lime and his lighthouse remained in use until 1877 and was dismantled and partially rebuilt at Plymouth Hoe where it is known as Smeatons Tower. The United States census of 1850 listed the occupation of engineer for the first time with a count of 2,000, there were fewer than 50 engineering graduates in the U. S. before 1865. In 1870 there were a dozen U. S. mechanical engineering graduates, in 1890 there were 6,000 engineers in civil, mining and electrical. There was no chair of applied mechanism and applied mechanics established at Cambridge until 1875, the theoretical work of James Maxwell and Heinrich Hertz in the late 19th century gave rise to the field of electronics
Chemistry is a branch of physical science that studies the composition, structure and change of matter. Chemistry is sometimes called the science because it bridges other natural sciences, including physics. For the differences between chemistry and physics see comparison of chemistry and physics, the history of chemistry can be traced to alchemy, which had been practiced for several millennia in various parts of the world. The word chemistry comes from alchemy, which referred to a set of practices that encompassed elements of chemistry, philosophy, astronomy, mysticism. An alchemist was called a chemist in popular speech, and the suffix -ry was added to this to describe the art of the chemist as chemistry, the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία and this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, which is in turn derived from the word Chemi or Kimi, which is the ancient name of Egypt in Egyptian.
Alternately, al-kīmīā may derive from χημεία, meaning cast together, in retrospect, the definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term chymistry, in the view of noted scientist Robert Boyle in 1661, in 1837, Jean-Baptiste Dumas considered the word chemistry to refer to the science concerned with the laws and effects of molecular forces. More recently, in 1998, Professor Raymond Chang broadened the definition of chemistry to mean the study of matter, early civilizations, such as the Egyptians Babylonians, Indians amassed practical knowledge concerning the arts of metallurgy and dyes, but didnt develop a systematic theory. Greek atomism dates back to 440 BC, arising in works by such as Democritus and Epicurus. In 50 BC, the Roman philosopher Lucretius expanded upon the theory in his book De rerum natura, unlike modern concepts of science, Greek atomism was purely philosophical in nature, with little concern for empirical observations and no concern for chemical experiments.
Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. He formulated Boyles law, rejected the four elements and proposed a mechanistic alternative of atoms. Before his work, many important discoveries had been made, the Scottish chemist Joseph Black and the Dutchman J. B. English scientist John Dalton proposed the theory of atoms, that all substances are composed of indivisible atoms of matter. Davy discovered nine new elements including the alkali metals by extracting them from their oxides with electric current, british William Prout first proposed ordering all the elements by their atomic weight as all atoms had a weight that was an exact multiple of the atomic weight of hydrogen. The inert gases, called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table.
Organic chemistry was developed by Justus von Liebig and others, following Friedrich Wöhlers synthesis of urea which proved that organisms were, in theory