Abd al-Rahman al-Khazini (flourished 1115–1130) was a scientist, astronomer, physicist, biologist, alchemist, mathematician and
philosopherEarly Islamic philosophy or classical Islamic philosophy is a period of intense philosophical development beginning in the 2nd century AH of the Islamic calendar and lasting until the 6th century AH...
from
MervMerv , formerly Achaemenid Satrapy of Margiana, and later Alexandria and Antiochia in Margiana , was a major oasis-city in Central Asia, on the historical Silk Road, located near today's Mary in Turkmenistan...
, then in the
KhorasanGreater Khorasan is a modern term for a historical geographic region spanning north-eastern and east of Iran, Turkmenistan, Uzbekistan, Tajikistan, western and northern Afghanistan and the North Western Areas of Pakistan...
province of Persia but now in
TurkmenistanRepublic of Turkmenistan is a country in Central Asia. Until 1991, it was a constituent republic of the Soviet Union, the Turkmen Soviet Socialist Republic...
, who made important contributions to
physicsPhysics is a natural science; it is the study of matter and its motion through spacetime and all that derives from these, such as energy and force...
and
astronomyAstronomy is the scientific study of celestial objects and phenomena that originate outside the Earth's atmosphere...
. He is considered the greatest scholar from Merv.
Robert E. Hall wrote the following on al-Khazini:
Biography
Al-Khazini was a
Byzantine GreekByzantine Greeks or Byzantines is a conventional term used by modern historians to refer to the medieval Greek or Hellenized citizens of the Byzantine Empire, centered mainly in Constantinople, the southern Balkans, the Greek islands, Asia Minor and the large urban centres of the Near East and...
slaveThe Arab slave trade was the practice of slavery in the Arab World, namely West Asia, North Africa, East Africa and certain parts of Europe during their period of domination by Arab leaders. The trade was focused on the slave markets of the Middle East and North Africa...
of the
Seljuq TurksThe Seljuq were a Turco-Persian Sunni Muslim dynasty that ruled parts of Central Asia and the Middle East from the 11th to 14th centuries...
, who at a young age was taken to
MervMerv , formerly Achaemenid Satrapy of Margiana, and later Alexandria and Antiochia in Margiana , was a major oasis-city in Central Asia, on the historical Silk Road, located near today's Mary in Turkmenistan...
after the Seljuq victory over the
ByzantineThe Byzantine Empire or Eastern Roman Empire, was the continuation of the Roman Empire during the Middle Ages, centered on the capital of Constantinople, and ruled by Emperors in direct and de jure succession to the ancient Roman Emperors...
Emperor Romanus IV. His master, al-Khazin, gave him the best possible education in mathematical and
philosophicalIslamic philosophy is a branch of Islamic studies, and is a longstanding attempt to create harmony between philosophy and the religious teachings of Islam .-Definition:...
subjects. Al-Khazini was also a pupil of the famous
Persian poetPersian literature spans two-and-a-half millennia, though much of the pre-Islamic material has been lost. Its sources have been within historical Persia including present-day Iran as well as regions of Central Asia where the Persian language has historically been the national language...
, mathematician, astronomer and philosopher
Omar KhayyámOmar Khayyám , , was a Persian polymath, mathematician, philosopher, astronomer and poet. He also wrote treatises on mechanics, geography, music and was a physicist....
(1048-1131), who was living in Merv at the time.
Al-Khazini later became a mathematical practitioner under the patronage of the Seljuk court, under Sultan
Ahmed SanjarAhmad Sanjar was the sultan of the Great Seljuq Empire from 1118 to 1153...
. Little else is known about his life, but it is known that he refused rewards and handed back 1000
dinarThe Dinar is the name of the official currency in several countries. The Gold Dinar was a coin dating back to the early days of Islam, issued by many rulers, and the Islamic gold dinar is a modern revival of it as a coin or unit of account, separate from the currencies listed below...
s sent to him by the wife of an
EmirEmir , is a high title of nobility or office, used throughout the Arab World and historically in 19th-century Afghanistan and also in the medieval Muslim World...
, and that he usually lived on 3 dinars a year.
Sinjaric Tables
Included in his
astronomicalIn the history of astronomy, Islamic astronomy or Arabic astronomy refers to the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age , and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia,...
treatise
az-ZijZīj is the generic name applied to Islamic astronomical books that tabulate parameters used for astronomical calculations of the positions of the Sun, Moon, stars, and planets. The name is derived from the Middle Persian term zih or zīg, meaning cord...
as-Sanjarī or
Sinjaric Tables, Al-Khazini gave a description of his construction of a 24 hour
water clockA 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 then measured.Water clocks, along with sundials, are likely to be the oldest time-measuring instruments, with the only exceptions being...
designed for astronomical purposes, an early example of an
astronomical clockAn astronomical clock is a clock with special mechanisms and dials to display astronomical information, such as the relative positions of the sun, moon, zodiacal constellations, and sometimes major planets.- Definition:...
, and the positions of 46 stars computed from the date given in the
AlmagestAlmagest is the Latin form of the Arabic name of a mathematical and astronomical treatise proposing the complex motions of the stars and planetary paths, originally written in Greek as by Ptolemy of Alexandria, Egypt, written in the 2nd century...
for the year 500 AH (1115-1116 CE). He also computed tables for the observation of celestial bodies at the
latitudeLatitude, usually denoted by the Greek letter phi gives the location of a place on Earth north or south of the equator. Lines of Latitude are the imaginary horizontal lines shown running east-to-west on maps that run either north or south of the equator...
of Merv.
Al-Khazini's
Zij as-Sanjarī was later translated into
GreekGreek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical...
by
Gregory ChoniadesGregory Choniades was a Byzantine Greek astronomer. He travelled to Persia where he learnt Persian mathematical and astronomical science which he introduced into Byzantium upon retun from Persia and founded an astronomical academy at Trebizond.Information about Choniades survives from some...
in the 13th century and was studied in the
Byzantine EmpireThe Byzantine Empire or Eastern Roman Empire, was the continuation of the Roman Empire during the Middle Ages, centered on the capital of Constantinople, and ruled by Emperors in direct and de jure succession to the ancient Roman Emperors...
.
The Book of the Balance of Wisdom
Al-Khazini is better known for his contributions to
physicsPhysics is a natural science; it is the study of matter and its motion through spacetime and all that derives from these, such as energy and force...
in his treatise
The Book of the Balance of Wisdom, completed in 1121, which remained an important part of
Islamic physicsPhysics in medieval Islam included experimental physics, mathematical physics and theoretical physics.The fields of physics that were studied by Muslim scientists during this time also included optics and magnetism , mechanics , and astrophysics .These studies...
. The book contains studies of the
hydrostatic balanceHydrostatic equilibrium occurs when compression due to gravity is balanced by a pressure gradient wihch creates a pressure gradient force in the opposite direction...
, its construction and uses, and the theories of
staticsStatics is the branch of mechanics concerned with the analysis of loads on physical systems in static equilibrium, that is, in a state where the relative positions of subsystems do not vary over time, or where components and structures are at a constant velocity...
and
hydrostaticsFluid statics is the science of fluids at rest, and is a sub-field within fluid mechanics. The term usually refers to the mathematical treatment of the subject. It embraces the study of the conditions under which fluids are at rest in stable equilibrium...
that lie behind it, as developed by his predecessors, his contemporaries, and himself. It also contains descriptions on the instruments of his predecessors, including the araeometer of
PappusPappus of Alexandria was one of the last great Greek mathematicians of antiquity, known for his Synagoge or Collection , and for Pappus's Theorem in projective geometry...
and the pycnometer
flaskLaboratory flasks are vessels which fall into the category of laboratory equipment known as glassware. In laboratory and other scientific settings, they are usually referred to simply as flasks...
of
al-Biruni' , often known as Alberuni, Al Beruni or variants, was a Persian polymath scholar of the 11th century....
, as well as his own hydrostatic balance and specialized
balanceBalance may refer to:*Analytical balance, a weighing scale.*Balance , an ability to maintain balance .*Balance *Media balance, the presentation of multiple viewpoints ....
s and
steelyardThe Steelyard, from the German Stalhof, was in the Middle Ages the main trading base of the Hanseatic League in London.-Location:It lay on the north bank of the Thames by the outflow of the Walbrook, its site now covered by Cannon Street Station and commemorated in the name of Steelyard Passage...
s.
Al-Biruni' , often known as Alberuni, Al Beruni or variants, was a Persian polymath scholar of the 11th century....
and al-Khazini were the first to apply
experimentIn scientific research, an experiment is a method of investigating causal relationships among variables, or to test a hypothesis. An experiment is a cornerstone of the empirical approach to acquiring data about the world and is used in both natural sciences and social sciences...
al
scientific methodScientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific...
s to the fields of
staticsStatics is the branch of mechanics concerned with the analysis of loads on physical systems in static equilibrium, that is, in a state where the relative positions of subsystems do not vary over time, or where components and structures are at a constant velocity...
and
dynamicsIn classical mechanics, analytical dynamics, or more briefly dynamics, is concerned about the relationship between motion of bodies and its causes, namely the forces acting on the bodies and the properties of the bodies...
, particularly for determining
specific weightThe specific weight is the weight per unit volume of a material. The symbol of specific weight is γ ....
s, such as those based on the theory of
balanceBalance may refer to:*Analytical balance, a weighing scale.*Balance , an ability to maintain balance .*Balance *Media balance, the presentation of multiple viewpoints ....
s and
weighingA weighing scale is a measuring instrument for determining the weight or mass of an object. A spring scale measures weight by the distance a spring deflects under its load. A balance compares the unknown weight to a standard weight using a horizontal lever...
. He and his Muslim predecessors unified statics and dynamics into the science of mechanics, and they combined the fields of hydrostatics with dynamics to give birth to hydrodynamics. They applied the mathematical theories of
ratioA ratio is an expression that compares quantities relative to each other. The most common examples involve two quantities, but any number of quantities can be compared. Ratios are represented mathematically by separating each quantity with a colon – for example, the ratio 2:3, which is read as the...
s and
infinitesimalInfinitesimals have been used to express the idea of objects so small that there is no way to see them or to measure them. The word infinitesimal comes from a 17th century Modern Latin coinage infinitesimus, which originally referred to the "infinite-th" item in a series.In common speech, an...
techniques, and introduced
algebraAlgebra is the branch of mathematics concerning the study of the rules of operations and the things which can be constructed from them, including terms, polynomials, equations and algebraic structures...
ic and fine
calculationA calculation is a deliberate process for transforming one or more inputs into one or more results, with variable change.The term is used in a variety of senses, from the very definite arithmetical calculation of using an algorithm to the vague heuristics of calculating a strategy in a competition...
techniques into the field of statics. They were also the first to generalize the theory of the centre of gravity and the first to apply it to
three-dimensionalThree-dimensional space is a geometric model of the physical universe in which we live. The three dimensions are commonly called length, width, and depth , although any three mutually perpendicular directions can serve as the three dimensions....
bodies. They also founded the theory of the ponderable
leverIn physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to multiply the mechanical force that can be applied to another object....
and created the "science of gravity" which was later further developed in medieval Europe. The contributions of al-Khazini and his Muslim predecessors to mechanics laid the foundations for the later development of
classical mechanicsIn the fields of physics, classical mechanics is one of the two major sub-fields of study in the science of mechanics, which is concerned with the set of physical laws governing and mathematically describing the motions of bodies and aggregates of bodies geometrically distributed within a certain...
in Renaissance Europe.
The first of the book's eight chapters deals with his predecessors' theories on the
centre of gravityThe center of mass of a system of particles is a specific point where, for many purposes, the system behaves as if its mass were concentrated there. The center of mass is a function only of the positions and masses of the particles that compose the system...
, including
Al-RaziAbū Bakr Muhammad ibn Zakariyā Rāzī , known as Rhazes or Rasis after medieval Latinists, was a Persian alchemist, chemist, physician, philosopher and scholar...
(
LatinLatin is an Italic language originally spoken in Latium and Ancient Rome. Through the Roman conquest, Latin spread throughout the Mediterranean and a large part of Europe...
ized as
Rhazes), Abū Rayhān al-Bīrūnī, and
Omar KhayyámOmar Khayyám , , was a Persian polymath, mathematician, philosopher, astronomer and poet. He also wrote treatises on mechanics, geography, music and was a physicist....
. He also draws attention to the failure of the
ancient GreeksAncient Greece is the civilisation belonging to the period of Greek history lasting from the Greek Dark Ages ca. 1100 BC and the Dorian invasion, to 146 BC and the Roman conquest of Greece after the Battle of Corinth. It is generally considered to be the seminal culture which provided the...
to clearly differentiate between
forceIn physics, a force is any agent that causes a change in the motion of a free body, or that causes stress in a fixed body. It can also be described by intuitive concepts such as a push or pull that can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a...
,
massIn physics, mass commonly refers to any of three properties of matter, which have been shown experimentally to be equivalent: inertial mass, active gravitational mass and passive gravitational mass...
, and
weightIn the physical sciences, the weight of an object is the magnitude, W, of the force that must be applied to an object in order to support it in a gravitational field. The weight of an object in static equilibrium equals the magnitude of the gravitational force acting on the object, less the effect...
, and he goes on to show awareness of the weight of the air, and of its decrease in
densityThe density of a material is defined as its mass per unit volume. The symbol of density is ρ .- Formula :Mathematically:where: is the density, is the mass, is the volume....
with
altitudeAltitude is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object...
. The strict definition for a specific weight is given by Al-Khazini in
The Book of the Balance of Wisdom:
After extensive
experimentIn scientific research, an experiment is a method of investigating causal relationships among variables, or to test a hypothesis. An experiment is a cornerstone of the empirical approach to acquiring data about the world and is used in both natural sciences and social sciences...
ation, Al-Khazini records the
specific gravitiesRelative density, sometimes called specific mass or specific gravity, is the ratio of the density of a substance to the density of a given reference material. Specific gravity usually means relative density with respect to water...
of fifty substances, including various stones, metals, liquids, salts, amber, and clay. The accuracy of his measures were impressive and comparable to modern values. In another experiment, Al-Khazini discovered that there was greater density of water when nearer to the Earth's centre, which was later proven by
Roger BaconRoger Bacon, O.F.M. , also known as Doctor Mirabilis , was an English philosopher and Franciscan friar who placed considerable emphasis on empiricism...
in the 13th century.
Al-Khazini defines heaviness in traditional Aristotelian terms as an inherent property of heavy bodies:
On the basis that there is denser air when nearer to the centre of the
EarthEarth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density...
(derived from the
Archimedes principleIn physics, buoyancy is the upward force that keeps things afloat. The net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body. This force enables the object to float or at least seem lighter....
), and that the
weightIn the physical sciences, the weight of an object is the magnitude, W, of the force that must be applied to an object in order to support it in a gravitational field. The weight of an object in static equilibrium equals the magnitude of the gravitational force acting on the object, less the effect...
of heavy bodies increase as they are farther from the centre of the Earth (derived from al-Quhi and Alhacen's theories that weight varies with the distance from the centre of the Earth), al-Khazini postulated that the
gravityGravitation is a natural phenomenon by which objects with mass attract one another. In everyday life, gravitation is most commonly thought of as the agency which lends weight to objects with mass. Gravitation causes dispersed matter to coalesce, thus accounting for the existence of the Earth, the...
of a body
varies with its distanceIn physics, action at a distance is the interaction of two objects which are separated in space with no known mediator of the interaction. This term was used most often with early theories of gravity and electromagnetism to describe how an object could "know" the mass or charge of another...
from the centre of the
EarthEarth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density...
:
It appears that what al-Khazini meant by "gravity" ("
thiql" in Arabic) is both an idea similar to the modern concept of gravitational potential energy,
and the
momentIn physics, the term "moment" can refer to many different concepts:*Moment of force is a synonym for torque, an important basic concept in physics, civil engineering, and mechanical engineering. In the context of mechanical engineering, the terms are not necessarily interchangeable, but one or the...
of a force relative to a point (both meanings were derived from al-Quhi and Alhacen). In either case, al-Khazini appears to have been the first to propose that the gravity of a body varies with its distance from the centre of the Earth. In his first sense of the word "gravity", the concept was not considered again until the 18th century, following
Newton's law of universal gravitationNewton's law of universal gravitation states that every object in this universe attracts every other object with a force which is directly proportional to the product of their masses and inversely proportional to the square of distance between their centres. This is a general physical law derived...
, but in his second sense of the word, the concept was considered again by Jordanus de Nemore in the 13th century.
N. Khanikoff, an early translator and commentator of al-Khazini's work, summarized his ideas regarding gravity as follows:
Treatise on Instruments
His
Risala fi'l-alat (
Treatise on Instruments) has seven parts describing different
scientific instrumentsLaboratory equipment refers to the various tools and equipment used by scientists working in a laboratory. These include tools such as Bunsen burners, and microscopes as well as specialty equipment such as operant conditioning chambers, spectrophotometers and calorimeters...
: the
triquetrumframe|Drawing of a triquetrum by Wilhelm Schickard, Basel University LibraryThe triquetrum was the medieval name for an ancient astronomical instrument first described by Ptolemy in the Almagest . Also known as Parallactic Rulers, it was used for determining altitudes of heavenly bodies...
,
dioptraA dioptra is a classical astronomical and surveying instrument, dating from the 3rd century BCE. The dioptra was a sighting tube or, alternatively, a rod with a sight at both ends, attached to a stand...
, a
triangularA triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
instrument he invented, the
quadrantNot to be confused with quartileQuadrant may refer to:* Quadrant , a measuring instrument capable of measuring angles up to 90°* In science-fiction: Galactic quadrants...
and
sextantSextants for astronomical observations were used primarily for measuring the positions of stars. They are little used today, having been replaced over time by transit telescopes, astrometry techniques, and satellites such as Hipparcos....
, the
astrolabeAn astrolabe is a historical astronomical instrument used by classical astronomers, navigators, and astrologers. Its many uses include locating and predicting the positions of the Sun, Moon, planets, and stars; determining local time given local latitude and vice-versa; surveying; and...
, and original instruments involving
reflectionReflection is the change in direction of a wavefront at an interface between two differentmedia so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves...
.
Alchemy and biology
Al-Khazini wrote the following on
evolutionIn biology, evolution is change in the genetic material of a population of organisms from one generation to the next. Though changes produced in any one generation are normally small, differences accumulate with each generation and can, over time, cause substantial changes in the population, a...
in alchemy and biology, comparing the
transmutation of elementsAlchemy is both a philosophy and a practice with an aim of achieving ultimate wisdom as well as immortality, involving the improvement of the alchemist as well as the making of several substances described as possessing unusual properties...
with the
transmutation of speciesTransmutation of species was a term used by Jean Baptiste Lamarck in 1809 for his theory that described the altering of one species into another. It was one of the names commonly used for evolutionary ideas in the 19th century before Charles Darwin published On The Origin of Species...
, and how they were perceived by
natural philosophersNatural philosophy or the philosophy of nature , is a term applied to the study of nature and the physical universe that was dominant before the development of modern science...
and common
laymenA "layman" is a person who is a non-expert in a given field of knowledge. The term originated from "laity", but over the centuries, shifted in definition....
in the
medieval Islamic worldThe Islamic Golden Age or the Islamic Renaissance, is traditionally dated from the 9th to 13th centuries for 400 years C.E., but has been extended to the 15th century by recent scholarship...
at the time:
See also
- Islamic science
Science in medieval Islam, also known as Islamic science, is a term used in the history of science to refer to the science developed in the Islamic world between the 7th and 16th centuries, a period also known as the Islamic Golden Age. Scientists from the region were also known to develop many...
- Islamic astronomy
In the history of astronomy, Islamic astronomy or Arabic astronomy refers to the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age , and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia,...
- Islamic Golden Age
The Islamic Golden Age or the Islamic Renaissance, is traditionally dated from the 9th to 13th centuries for 400 years C.E., but has been extended to the 15th century by recent scholarship...
- Muslim inventions
- Zij
Zīj is the generic name applied to Islamic astronomical books that tabulate parameters used for astronomical calculations of the positions of the Sun, Moon, stars, and planets. The name is derived from the Middle Persian term zih or zīg, meaning cord...