Welcome to the A-Z of Scientific Instruments. Don't know your telescope from a pocoscope, or an astrolabe from an abacus? This part of the Scientific Instrument Society website is there to put you right. All entries have been written by SIS members and, where appropriate, they have included useful book references and weblinks as well. This is an ongoing project and more instruments will be added to the A-Z on a regular basis. Feel free to with suggestions for improvements or additions to the list. if you'd like to write an entry or to make suggestions for improvements or additions to the list.
Key:
Book related to item
Web link for more information
Previously published resources which have proved of particular use in compiling this A-Z include the following (click items to view on Amazon.co.uk).
Havyatt, V., 1981
A Dictionary of Measuring Instruments
Macleay Museum
University of Sydney
List of contributors to the SIS A-Z of Scientific Instruments
RB = Ron Bristow
MC = Marcus Cavalier
PG = Paul Goodman
NH = Neil Handley
PM = Patrick Mill
DR = David Riches
Abacus
A mathematical instrument of simple but timeless form. The name, which has existed in English since at least the later 14th century, derives from the Ancient Greek word for 'disc' or 'table' (abakos). In the ancient world an abacus was a flat surface for reckoning accounts, not necessarily an object but sometimes just an area marked out in the sand and often with pebbles as tokens.
The oldest abacus yet discovered, on the Greek island of Salamis, dates from c.300 BC. Roman abaci took either the form of a wooden calculating board or a bead abacus with counters that moved along in slots. The latter form was convenient enough to hold in the hand. Bead-frame abaci developed in many countries including in the Far East where the beads adopted distinctive shapes. The beads can be slid along a frame of parallel rods or wires. The abacus is often seen as the symbol of the Victorian schoolroom, where despite its significance in the teaching of numeracy it may be dismissed as a 'toy' example. The Cranmer abacus is an adapted didactic tool for the visually impaired. More tongue-in-cheek, the abacus has sometimes be used as a symbol of the history of computing.
Also known as: counting frame
Pullan, J. M., 1968, The History of the Abacus, Books That Matter, London
NH
Abney Level
A surveying instrument. A variant of the clinometer (q.v.) invented by William Abney of the School of Military Engineering, Chatham, Kent. It reads the angle through which a pivot has been turned.
Addition machine
A mathematical instrument for arithmetical calculation by means of a mechanical gearing arrangement. First invented by Wilhelm Schickhard in 1623 their development is associated particularly with Blaise Pascal in the 17th century. His addition machine of 1645 went into some form of pre-commercial production before 1652. In 1672 Gottfried Liebnitz introduced a variant that was capable of performing multiplication tasks.
Also known as: Pascalina, Pascaline, Arithmetique
Air pump
A pneumatic instrument used in physics demonstrations to create a vacuum within a container or space, or to condense air into a closed space. First invented by Otto von Guericke (1654)in the form of Magdeburg hemispheres, an improved single cylinder design was produced by Robert Hooke in Oxford in 1658 whilst he was assisting Robert Boyle's research into gases. On the European Continent the Van Musschenbroeks produced large-bore single cylinder models in the eighteenth century whereas in England the twin-barrel design as exemplified by the models of Francis Hauksbee attained popularity. An air pump is the subject of a famous painting by Joseph Wright of Derby: 'An Experiment on a Bird in the Air Pump' (1768) in which a cocaktoo within the flask is gradually deprived of oxygen before a mixed audience of adults and children.
Also known as: air compressor, vacuum chamber, vacuum pump
Hauksbee, F., 1709, Physico-Mechanical Experiments
See also: Vacuum flask
NH
Air Speed Indicator
Navigational instrument for measuring the velocity of an aircraft relative to the air through which it moves.
RB
Analytical machine
A mathematical instrument for performing calculations and, unlike the Difference Engine, capable of carrying out any mathematical operation. Charles Babbage designed his prototype in 1834 but he never started production as he still hadn't completed his Difference Engine and so no further funding could be obtained. If built, it would have been steeam powered and programmable using punched cards. A few working test models for specific components of the machine have survived including a portion of the 'mill' with printing mechanism to be found in the Science Museum, London.
Also known as: Analytical engine
Swade, D., 1991, Charles Babbage and his Calculating Engines, Science Museum, London
Component of the Analytical Engine
See also: Difference engine
NH
Antigraph
Mathematical/Drawing instrument. An instrument for drawing parts of a figure the reverse hand to the original. It consists of a three-wheeled carriage, which is designed to run perfectly straight. It is centred on a line midway between the image to be copied and the location of the reverse image to be drawn. Two arms project forward of the carriage and are geared together such that the movement of one is mirrored by the other, One of these arms carries a tracing point and the other a pencil.
Stanley, W.F., 1900, 'Mathematical Drawing and Measuring Instruments', 7th edn, E & FN Spon.
DR
Archimedean screw
A mechanical instrument often reproduced, since the 18th century, as a laboratory demonstration model in which a ball is made to rise up an inclined plane. The original device, to raise water for irrigation purposes, was traditionally ascribed to the invention of Archimedes circa 350 BC and consisted of a spiral helix or helices surrounding the inclined plane, sometimes within a tube and powered by a treadmill or waterwheel. Pescalators are a form of Archimedean screw designed to lift fish from a pond.
Also known as: Archimede's screw, Cochlea, Screwpump
Similar to: Caged screw, Pressurised screw
See also: Inclined plane
NH
Architectural Proportional Rods
Mathematical instrument. Triangular brass rods, in sets of five, for calculating the elements of the five classical orders of architecture.
Hambly, M., 1988, 'Drawing Instruments 1580-1980', Sothebys Publications
DR
Areometer
A hydrostatic instrument to measure the specific gravity of liquids. The use of Nicolson's areometer (brass) was described by Frick in 'Physical Technics; Or, Practical Instructions for Making Experiments in Physics' (1862). In essence Nicholson's instrument drew upon the principles outlined by Boyle in 1675. Fahrenheit's areometer was made of glass so that it would not react with any of the liquids in which it was immersed.
Also known as: araeometer, hydrometer
Elements of Mechanics by W.G. Peck, 1859
See also: hydrometer
NH
Arithmometer
A mathematical instrument produced in Paris in 1820, generally regarded as the first commercially successful calculating machine. The arithmometer of C.X. Thomas was a long wooden box with apertures through which to view the numbers. It owed much to the theory behind Leibniz's multiplying machine of the 1670s
Also known as: Thomas machine
A Brief History of Mechanical Calculators Part II
Armillary sphere
An astronomical instrument which has often been regarded by writers and artists as the very symbol of astronomy. The Ancient Greeks and Chinese both developed the instrument independently from the 3rd century BC and a similar form of device was developed by scholars in countries under Islamic rule from at least the 8th century AD. Large observational examples were erected in early observatories particularly before the advent of the telescope, but portable, often hand-held instruments survive from the 15th century onwards.These were usually demonstrational in function. Skeletal in appearance, the armillary sphere comprises numerous concentric rings that together indicate the heavens including the equatorial and celestial circles, the poles and tropics and against which the observer could plot the position of other celestial bodies. The design of armillaries changed as understanding of the solar system developed from a Ptolemaic arrangement with a ball to represent the earth at the centre, to a Copernican system centred around the sun. In the second half of the sixteenth century Tycho Brahe combined armillary spheres with astrolabes whilst Queen Elizabeth I of England had a pair of ear-rings in the shape of armillary spheres. Wooden and pasteboard examples were used for teaching but some very fine examples of precious metal and other materials were produced for aristocratic libraries where they often formed a set with one or more globes.
Also known as: celestial sphere, celestial globe, spherical astrolabe
See also: astrolabe
NH
Artificial horizon
A Navigational instrument used on land, traditional forms of which consisted of a glazed wooden box containing a trough of liquid mercury. Modern examples employ a bubble level attached to a black glass plate supported by levelling screws. Attitude indicators are a form of artificial horizon used in aircraft to inform the pilot of his orientation relative to the earth.
John Charles Fremont - The Artificial Horizon
NH
Astrolabe (mariner's)
Astrolabe (planispheric)
A mathematical instrument to facilitate angular measurement for purposes of surveying or astronomy. The name literally translates as 'star-taking'. Astrolabes are commonly of brass, circular in shape and outlined with a stereographic projection of the globe and the hemisphere of the heavens. The outer 'limb' comprises a 360 degree scale against which the rule (alidade) may be aligned to measure the altitude of a star by cross-reference to a revolving disc (rete). The instrument shows two distinct lines of development: Islamic and Western European. The Islamic type originated in Syria in the 9th century and penetrated to Spain via North Africa in the 10th century. They were still being manufactured in the 20th century due to their use as a calculating device for the times of Muslim prayers. Western astrolabes were produced around various centres including England, France, Germany and the Netherlands.
Chaucer, G., 1391 'The Treatise on the Astrolabe'
See also: Astrolabe (spherical)
NH
Astrolabe (spherical)
A mathematical instrument to facilitate angular measurement for purposes of surveying or astronomy. Spherical astrolabes comprised a model of the globe and heavens. Only one complete example is known to exist.
Atwood Fall machine
A mechanical instrument. George A(t)twood's machine, described in 1784, was taller than a man and consisted of a complex pulley system atop a wooden column to demonstrate the acceleration and retardation of bodies according to Newtonian laws of motion. A simple Atwood machine can be rigged up with two masses (weights) suspended over a pulley and photogates or more traditional timing mechanism. The design of passenger lift machinery is dependent upon the same principles.
Martins, D.R. and Providencia, J. da., 2000, 'The Poleni machines of the Universities of Padua and Coimbra and the instruments to study motion due to gravity', Bulletin of the Scientific Instrument Society 66, pp.23-25
NH
Avometer
Trade name. Electrical instrument. A particular multimeter made and trade-marked by the AVO company.
See also: Multimeter
RB
Back-staff
Balance
Barometer
Meteorological/philosophical instrument that measures the pressure or weight of air. Their invention is traditionally ascribed to Evangelista Torricelli in 1644. By the early eightenenth century makers such as John Patrick could be found specialising in barometers. A typical instrument has a glass tube with a vacuum at the sealed top and an open bottom end descending into a cistern of mercury. A variation, beloved of school physics experiments, consists of a bent or siphon tube. Eighteenth century barometers were mainly of the stick type, encased in mahogany or other ornamental woods and mounted on a wall or combined with thermomemters or clocks. Mountain barometers were used for measuring high altitudes from at least 1800. Some were used in conjunction with a thermometer and sent to altitude in a hot-air balloon. Barometers to measure the depths of mines employed a similar principle in the opposite context. The aneroid barometer (fluidless), which uses metal bellows, was invented by Lucien Vidie in 1845 and pocket versions were developed in the 1860s. Prominent barometer makers have included Daniel Quare, W & S Jones, Negretti & Zambra, W. F. Stanley.
Also known as: Weather glass
NH
Barometer (Liegeois)
Meteorological/philosophical instrument for measuring air pressure. A particular type of barometer pioneered by the glass blowers of Liege in the early eighteenth century and thereafter common to the Netherlands. They are filled with water and pressure causes the water to rise up a spout, allowing the amateur prediction of storms.
NH
Barometer (Marine)
Meteorological/philosophical instrument for measuring air pressure, in particular to predict storms, whilst compensating for the movement of a ship. The first successful model, with a constricted tube, was made by Edward Nairne and was taken on Captain Cook's second voyage to the Pacific in 1772. It seems these early marine barmeters could swing freely while suspended within a four-legged frame. The partnership of Nairne & Blunt produced many from 1773. Later models did away with the stand and were instead weighted at the cistern or fixed to the bulkhead by a supporting arm. It has been suggested that Matthew Berge was the originator of the 'weighted chimney' form of barometer with a brass tube and lead collar. Gimbal arms were certainly in use by the early nineteenth century. Heavier brass-covered cistern barometers did away with the need for specific weighting by the 1820s.
McConnell, A., 2005, 'The Origins of the Marine Barometer', Annals of Science 62-1, pp.83-101
Marney, P. and McConnell, A., 2008, 'Weighted Marine Barometers', Bulletin of the Scientific Instrument Society 96, pp.10-13
NH
Barometer (Wheel)
Meteorological/philosophical instrument for measuring air pressure. An early type of barometer devised in the 1660s working on the siphon tube principle but employing an addition weighted pully system to record the movement of the mercury against a circular dial, behind which the tube is concealed. It proved particularly popular in 19th century banjo-shape barometers, often made in Great Britian by workers of Italian origin, for example Negretti & Zambra.
Also known as: Banjo barometer
NH
Binnacle
Binoculars
Bismar
Burning Glass
Spargo, P.E., 1984, 'Burning Glasses', Bulletin of the Scientific Instrument Society 4, pp.7-8 [N.B. Errata concerning figure captions corrected in Issue 5 p.23]
Camera
Camera lucida
An optical/drawing instrument employing a prism, that enables a scenic view and the artist’s drawing paper to be viewed simultaneously, invented by William Wollaston in 1806. In its usual form the prism is mounted at the upper end of a telescopic arm, which has at its lower end a table clamp. It is arranged so that its position can be adjusted to suit the drawing in hand. There may also be a set of lenses, used in conjunction with the prism, to vary the size of the projected image. An adaptation of it can be used with a microscope, to aid the drawing of microscopic objects.
Turner, G., 1998, Scientific Instruments 1500-1900 An Introduction, Philip Wilson, London p.100
DR
Camera obscura
Centrolinead
A drawing instrument, essentially a simple form of Delineator for producing perspective drawings with inaccessible vanishing points. It comprises three arms joined together at their ends by an adjustable joint, which enables them to be clamped at angles to each other. Two equal length arms are clamped together, usually at a fairly wide angle, and these are arranged to move about two special pins which are placed in the drawing board near the edge. The third, usually longer, ruling arm is clamped to bisect the external angle formed by the other two arms. As the instrument is moved in contact with the pins, it will move in an arc about a point, which is some way off the drawing board, and this will be the desired vanishing point. A line drawn along the ruling arm will be a line of perspective from that vanishing point. Its invention has been credited to Peter Nicholson in 1814, although John Farey claimed later to have invented a similar delineator in 1807.
Hambly, M., 1988, Drawing Instruments 1580-1980, Sothebys, London
DR
Chartometer
A drawing instrument for measuring the length of curved lines on maps, charts and drawings. It usually comprises a tracing wheel, connected by a gear train to a dial for displaying the measurement.
Also known as: curvimeter, map measurer, map wheel.
DR
Chondrometer
A weighing instrument traditionally constructed on either the counter steelyard or equal arm beam principle, for testing grains of corn or maize, used especially in agriculture or for customs purposes. The quality of the grain is determined by the heaviness of a test weight of grains and its packing density or specific gravity. An Improved Pocket Chondrometer was supplied by J. Bleuler in the early 19th c. From 1923 the Sydney firm of A.L. Franklin produced chondrometers including the New South Wales Standard Chrondrometer, and a simplified design known as the 'Growers' Personal Chondrometer. Digital chondrometers are now available.
Also known as: corn scale
NH
Chromometer
A chemical instrument. The 'Universal Chromometer' was introduced to the oil industry by George M. Saybolt in 1919 as a modified version of Stammer's colorimeter. It determined the colour shades of refined petroleum.
See also: Colorimeter
Chronometer
Circumferentor
Clinograph (Harrison's Patent)
A mathematical/drawing instrument. A Set Square having a fixed right angle and a movable arm, the joint being flush with the surface so that it may be used on either side. Frequently made of mahogany, but sometimes celluloid.
DR
Clinometer
A surveying instrument consisting of a wheel and weight and a marked scale, for measuring vertical angles or slopes. Often incorporated as part of a prismatic compass or other instrument. Clinometers are useful for climbers when measuring slopes to be ascended or sailors when measuring the roll of a ship. They may be liquid-filled. In the late 19th century electric clinometers were designed incorporating a potentiometer.
Also known as: gradiometer, inclinometer, level gauge
See also: Abney Level
NH
Clinometer Rule
A simple form of surveying instrument basically consisting of two stout boxwood arms hinged together by a hinge that includes a protractor to measure the angle between the arms. One or often both arms house a spirit level. It is normally used in the vertical plane and the upper arm has sights on both ends. There are usually angle/rise tables on the lower arm so that the height of an object can be calculated from the angle measured and the distance of the level from the object. It can also be used to measure the angle of inclination of an object from the horizontal. Sometimes the lower arm also contains a small magnetic compass.
DR
Clock
Colorimeter
A chemical instrument for comparing the colour of substances. Years after the event Jules Duboscq claimed to have designed the first one in 1854. Certainly instruments were made to his basic design well into the 20th century. Other significant designs by Jules Salleron (France) and Karl Stammer (Germany) were manufactured by Franz Schmidt & Haensch. Colorimeters had uses in the metallurgical, dye, sugar and wine industries.
Warner, D.J., 2008, 'Instruments for Quality and Process Control', Bulletin of the Scientific Instrument Society 96, pp.3
See also: Chromometer, Tintometer
Compass (azimuth)
Compass (Beam)
A drawing instrument. A device for drawing large radius circles, it comprises a beam or lath, made of wood or metal, and two trammel heads or fittings, at least one of which is able to slide along the beam to set the radius. One fitting, often fixed at one end of the beam, carries the point, and the second fitting may usually be fitted with either another point, a pen, or a pencil/pencil lead.
DR
Compass (Bow)
A drawing instrument. A small drawing compass, usually having limbs between 75 and 100 mm long.
DR
Compass (Drawing)
A drawing instrument. A device for drawing circles. It can take a wide variety of forms and has been known since antiquity.
DR
Compass (Drop Bow)
A drawing instrument. A drawing compass which comprises a hollow fixed limb, through which the point can move, and a spring limb, carrying the pen or pencil lead, attached to the fixed limb. In use the point is held on the paper by a handle at its upper end whilst the rest of the compass is rotated about it. It is fitted with an adjusting screw, which opens the compass against the spring. It is normally used for drawing very small circles. Sometimes known as a Pump Bow, which is a special form in which the point is sprung.
Also known as: rotating compass
DR
Compass (Half Set)
A drawing instrument. A drawing compass complete with extension bar, pen, pencil and divider inserts and a knife key.
DR
Compass (magnetic)
Compass (mariner's)
Compass (Napier)
A drawing instrument. A folding pocket drawing compass. One limb is fitted with a point and pen and the other with a point and pencil lead, these being pivoted so that by selecting different combinations the compass can function as a pen or pencil compass or as a divider. The limbs are jointed midway so that the pivoting ends fold into recesses in the limbs, which then fold together at the head joint.
DR
Compass (prismatic)
A form of magnetic compass used for accurately measuring bearings and angles between objects. The compass is mounted with a sight (the foresight) and, directly opposite it, a prism, which is mounted on the backsight in such a way that the user can view the object of interest through the sights and also see the compass card, which rotates rather than a needle. The user can then read the bearing accurately from the compass card whilst the object is in the sights. They were widely used for surveying and military purposes. The surveying ones are larger and could often be mounted on a tripod for accurate work. The military ones, typically two inches in diameter, can be folded for carrying in the pocket, and the foresight is incorporated into the lid. They are frequently oil filled so that the compass card settles more rapidly and steadily.
DR
Compass (proportional)
A mathematical/drawing instrument. Also, perhaps more accurately, known as Proportional Dividers, proportional compasses consist of two arms, each having a point at each end, which are joined together by a pivot which can be either fixed, to give a specific ratio, or sliding, so that the ratio can be varied. They are used for scaling from one drawing to another, typically for producing enlarged or reduced scale copies. Christoph Scheiner has been credited with inventing these in 1603, although variable proportional compasses designed by Jost Burgl in 1588 exist, Leonardo da Vinci sketched both types c.1495, various other designs from the 16th century are known, and a fixed ratio Roman example has been found in the ruins of Pompeii.
Also known as: proportional dividers
Pearsall, R., 1974, Collecting and Restoring Scientific Instruments, David & Charles, London
Hambly, M., 1988, Drawing Instruments 1580-1980, Sothebys, London
DR
Compass (Rotating): see Compass (Drop Bow)
Compass (Spring Bow)
A drawing instrument. A drawing compass in which the two limbs are connected by a C spring or are themselves springy and fixed together at the head. It is fitted with an adjusting screw, which opens the compass against the spring.
DR
Co-ordinatograph
Drawing instrument for accurately marking the stations on survey plans and the points lying between intersections determined by co-ordinates.
DR
Counting frame: see Abacus
Crossed-cylinder
Cross-staff
Curves (Flexible)
A drawing instrument. A thin, flexible band of steel or celluloid which could be formed to the shape of the desired curve and drawn around. Mr J W Brooks invented four different types. A more recent form of flexible curve consisted of lead core, sheathed in plastic.
DR
Curves (French)
A drawing instrument. Drawing templates with curves of varying radius and irregular shape made in many patterns. Originally made of thin wood, they were also made from vulcanite, celluloid and plastics.
Also known as: irregular curves.
DR
Curves (Railway)
A drawing instrument. Drawing templates of constant radius sold in sets of from 25 to 100 and typically varying in radius from 1.5 to 30, 120 or 240 inches depending on the size of set. Similar were Railway Degree Curves, sold in sets of 40, with tangents from 30 minutes to 11 degrees to a scale of 1 inch to 100 feet. Typically made of mahogany, varnished card or celluloid.
DR
Curves (Ship)
Drawing instrument. Drawing templates of varying radius and irregular shape intended for use by naval architects. The Admiralty Pattern consisted of 40 different curves and sets of nine, fifteen or forty were sold. Kemp’s Pattern consisted of five heart-shaped curves. Sets of Yacht Curves were also made, broadly similar to Admiralty Pattern Ship’s Curves.
DR
Delineator
Drawing instrument, for producing perspective drawings in which the vanishing point or points are inaccessible. Various designs were produced from about 1800 onwards.
Hambly, M., 1988, Drawing Instruments 1580-1980, Sothebys, London
See also: Camera lucida, Centrolinead.
DR
Dewar flask: see Vacuum flask
Difference machine
Mathematical instrument for performing calculations. The name is used to describe both Muller's machine of 1786 for producing mathematical tables and Babbage's instrument of 1822 which never progressed beyond the prototype stage.
A Brief History of Mechanical Calculators Part II
Dioptrescope: see Focimeter
Dip circle
Dipleidoscope
Dividers
A mathematical/drawing instrument for taking a measurement from a scale or drawing and transferring it to a drawing or scale. It usually comprises two limbs, jointed at the head, with points at the opposite ends. The name derives from their other use for dividing lines and circles into a number of equal divisions.
DR
Dividers (Proportional): see Compass (Proportional)
Dividers (Spacing)
A mathematical/drawing instrument. A special form of divider, usually having eleven points, connected by a matrix of limbs, used to divide a measurement or line into a number (from two to ten) of equal parts. An earlier form was known as a Sectograph.
DR
Drafting Machine
Mathematical/drawing instrument. An attachment to a drawing board consisting of a jointed parallel motion terminating in a protractor with a pair of scales attached to it at right angles to each other, such that they could be set to any desired angle in relation to the board horizontal and would maintain that angle wherever placed on the board surface. Used instead of a T Square and Set Squares.
DR
Eccentrolinead
Drawing instrument. A rule with, near one end, a pivoted arm with a needle point on the end, which is used to draw excentro-radial lines. In use the pin is placed in the centre of the circle and the arm is moved on its pivot to give the required amount of offset of the lines from the centre and clamped. It was typically used to draw the spokes of a wheel.
Also known as: Excentrolinead.
DR
Eidograph
Drawing instrument. William Wallace, Professor of Mathematics in Edinburgh, invented the Eidograph in 1821. It was a device for producing enlarged or reduced copies of drawings and was said to do so more accurately than the Pantograph. A central beam sat on a pivot weight, it’s position depending on the scale of enlargement or reduction. At each end of the central beam there was a wheel and attached to these wheels were the tracing and drawing beams, the points of attachment again depending on the scale. The two wheels were linked by a continuous band with spring steel ends around the wheels so that angular movement of the tracing beam (relative to the central beam) was transmitted directly and accurately to the drawing beam.
Wallace, W., 1836, Transactions of the Royal Society of Edinburgh 13, pp. 418-439
Hambly, M., 1988, Drawing Instruments 1580-1980, Sothebys, London
See also: Pantograph.
DR
Electrometer
Electrical instrument for measuring electric charge or potential difference. A reading in volts is obtained dependent upon the degree of attraction or repulsion caused by plates or wires when electrical charge is passed through them. Lord Kelvin's Quadrant Electrometer of 1867 was renowned for its high level of accuracy. Modern electrometers use vaccum tube (valve type) or solid state technology (voltage balancers) to measure very small levels of charge and sometimes voltage, resistance and current too. Vibrating reed electrometers contain one fixed and one vibrating electrode and can be used in confined spaces with an amplifier attached by a wire at some distance from the probe. Electrometers that monitor leakage of charge can be used to detect ionising radiation. Faraday Cup Electrometers are used in the study of aerosols. A similar, less precise, instrument producing only relative readings is the electroscope.
NH
Ellipsograph
Drawing instrument for drawing small ellipses invented in the late eighteenth century. The first English one was devised by John Farey c.1810 and several of these exist in museums and private collections. Since then there have been a multitude of different designs and patents.
Hambly, M., 1988, Drawing Instruments 1580-1980, Sothebys, London
DR
Elliptical Trammels
Drawing instrument for producing larger ellipses which comprises two main parts. The first is a cruciform base with channels in its arms, typically 90mm square. The second is a beam with a drawing point on one end and two adjustable sliding heads, which slot into the channels and slide in them as the drawing point is moved, constraining it to draw an ellipse. Semi-Elliptic Trammels are similar but have a T shaped base. They can be used to draw smaller ellipses but only draw one half at a time, having to be reversed to draw the complete ellipse.
DR
Ell rule
Mathematical instrument for measuring lengths of cloth. The English ell (45 inches, or one and a quarter yards) was officially introduced by Queen Elizabeth I in 1588 and remained a legal measure until 1824. The Scottish ell was shorter (37 inches) and the Flemish ell considerably shorter still, at between 26 and 27.5 inches. A Danish example in mahogany is known with six-inch divisions totalling 24 inches. Ell rules are usually of wood with inlaid brass scales or ivory and brass ends. Some ell rules are marked for more than one national length of ell. Elaborate Mughal examples of ivory are known and it is suggested that they were for measuring the silk to make turbans.
NH
Eyeglasses: see Spectacles
Fish plate
An accessory for a microscope allowing the user to observe the blood flow in the tail fin capillaries of a fish. Fish plates were used to demonstrate William Harvey's theory of circulation which he had first proposed in 1628.
Focimeter
Optical instrument for measuring the power (spherical and cylindrical) of lenses and indicating the axis of cylindrical lenses. Snellen's phakometer of 1876, although akin to an optical bench, was the ancestor of the focimeter, the first example of which was designed in 1912. Modern examples can usually be angled against their base for ease of operation and often show a closer resemblance to a microscope. A light source is directed through the lens, which may rest on a platform. This causes a graticule or ring of dots to appear in the eyepiece of the instrument when the focusing wheel is turned to the correct position. The lens power can then be read off a scale. Projection focimeters, where the target image appears on a frosted glass plate, emerged in the 1950s.
Also know as: Lensmeter (trade name), Dioptrescope
NH
Frictional electrical machine
Galvanometer
Geissler tube
Globe
Gramophone
Graphometer
Trade name. A type of gramophone marketed by the Columbia Phonograph Company. It was available in cylinder or disc styles and won the Grand Prix at the Paris Exposition in 1900.
Graphophone
Gravimeter
Gunter's chain
Gyroscope
Harmonic Analyser
Mathematical designed to carry out the analysis of complex waveforms by the action of tracing a curve. Two planimeters measure the areas enclosed by the paths traced out by two small depressions on the surface of gear wheels; the areas so measured are proportional to the corresponding coefficients in a Fourier series representing the curve traced. A series of gear wheels is provided corresponding to the 1st (fundamental), 2nd, 3rd, 4th, etc. harmonics.
W F Stanley & Co Ltd, 1958, ‘A’ Edition Catalogue
DR
Helicograph
Drawing instrument for drawing spiral lines. Typically these consist of a compass beam having a fixed point at one end and a sliding member with the drawing point attached. As the beam is rotated about the point so a line attached to the carriage is wound around a helically grooved cone, drawing the carriage towards the centre of rotation. Sets of different cones allowed different spirals to be drawn.
DR
Hodometer
Hour glass: See Sand glass
Hydrometer
A hydrostatic instrument to measure the specific gravity of liquids. In 1675 Robert Boyle's description of a glass instrument with a 'bubble' to be immersed in liquids appears to outline the hydrometer principle. Most hydrometers consist of a brass or thin glass tube ending in a sphere that leads into a smaller weighted sphere. The instrument will sink deeper into less dense liquids. Specific types of instrument were designed for use with acids and alkalis. In the 18th century hydrometers were used in brewing and by excise officers to check the results! The Clarke pattern of hydrometer with attendant weights, was designed in 1730 and described by Desaguliers. Almost all hydrometers made after this date until the early 19th century were Clarke's, featuring his distinctive mark of the half moon and dagger on the lower brass spindle. The most famous model of hydrometer is that of Sikes (1817) of which good examples were supplied by R.B. Bate. ('Bate of the Poultry'). More recent uses include testing car battery acid.
McConnell, A., 1993, R.B. Bate of the Poultry 1782-1847: The Life and Times of a Scientific Instrument-Maker, Scientific Instrument Society Monograph 1
Classic encyclopedia: Hydrometer
See also: areometer
NH
Hygrometer
Inclined plane
A mechanical instrument in the form of a laboratory model to demonstrate the force required to draw an object (carriage) up a slope to various heights and the effect of friction. An inclined plane is an essential element to an Archimedean screw. The name is also used more generally to denote a functional sloping surface such as a ramp, a blade or a wedge. Galileo's 'Discourses on Two New Sciences' (1638) described a famous inclined plane experiment utilising a grooved wooden board, some seven metres long, down which he rolled a bronze ball to study the effect of acceleration on motion.
Early 19th century inclined plane
See also: Archimedean screw
NH
Integrator
Mathematical instrument for determining the area and other properties of a plane figure. Depending on the type of integrator it would also measure the static moment, the moment of inertia (2nd moment of area), and the 3rd moment. These properties are particularly useful to mechanical and civil engineers and naval architects.
DR
Intergraph
Mathematical/drawing instrument. A mechanical device for obtaining the numerical value of a definite integral whilst at the same time recording the progress of integration by drawing the integral curve. Whilst the tracing point follows a given curve, the Intergraph automatically draws the integral curve, the ordinates of which are proportional to the corresponding areas under the given curve.
W F Stanley & Co Ltd, 1958, ‘A’ Edition Catalogue
DR
Isograph
Mathematical instrument. A form of adjustable set square invented by W F Stanley consisting of two boxwood arms joined by a brass hinge engraved with a degree scale for setting the angle between the arms.
DR
Jealousy glass
Also known as: Polemoscope
Mills, A., 1993, 'The Polemoscope', Bulletin of the Scientific Instrument Society 39, pp.28
Kaleidoscope
Keratometer
Keratoscope
Lensmeter: see Focimeter
Lensometer: see Focimeter
Lens trier
Level
Levelling Staff
Leyden jar
Liquiscope
Trade Name. Optical instrument designed by M. Sonden of Stockholm c.1891 for analysing oils and fats.
See also: Refractometer
Lodestone
Machmeter
Navigational instrument, usually in aircraft, an instrument for measuring Mach Number which is the ratio of speed to the speed of sound.
RB
Maddox rod
Magic lantern
Magnet
Magnifying glass
Optical Instrument. A mounted or unmounted convex lens of shorter focal length and usually rather smaller size than a reading glass (q.v.)
Mills, A., 1997, 'Single Lens Magnifiers, Part II: Magnifying Glasses', Bulletin of the Scientific Instrument Society 55, pp.30-32
Micrometer
A mathematical instrument for measuring extremely small units of length precisely.
Microscope
Mirror
Multimeter
Electrical instrument combining a voltmeter, ammeter and ohmmeter with function and range selector switches.
RB
Multiplication machine
Napier's Bones
Newton's Rings
Nocturnal
Octant
Offset
Mathematical/surveying instrument. A small scale rule, usually two inches long, used at right angles to a chain scale for plotting offsets measured during chaining.
DR
Oograph
Drawing instrument. For drawing egg-shaped ovals.
DR
Opera glass
Ophthalmometer
Ophthalmoscope
Ophthalmotrope
Opisometer
Mathematical instrument. A simple device for measuring the length of curved lines on maps and plans. It consisted of a handle terminating in a wheel mounted on a screw. To use it the wheel was screwed fully to one end, and then traced along the line to be measured. Next it was applied to a scale and wheeled back until it returned to the starting end. The length of the line measured equalled the length of scale traversed.
DR
Opsiometer
Optical instrument, effectively an early form of refracting unit for self-directed use, patented in the late 19th century by J Raphael and Co. of London. It comprised two rolls of lenses mounted on fabric, fixed inside a wooden case with viewing apertures at the front, a test target at the back and control knobs at either side. The Bruce Refracting Unit, (1889) was a binocular variation.
NH
Optical bench
Optical Square
A surveying instrument used for measuring long perpendiculars during chaining. It consists of a small circular box containing two mirrors fixed at an angle of 45 degrees to each other, so that any two objects seen it, one by direct vision and the other by reflection subtend an angle of 90 degrees at the place of the observer. The observer walks along the chain line until the object to which the perpendicular (offset) is to be measured appears coincident with a flag marker on the chain line in front. It can also be used to set up a perpendicular to a point on the chain line.
DR
Optometer
Orrery
Pantograph
Mathematical/drawing instrument. A device for copying maps and drawings to a reduced, enlarged or similar scale. Christoph Scheiner is credited with its design, c.1603. In its early form it consisted of a wooden parallelogram formed from six rods, two of which were double the length of the others, jointed like lazy tongs and had a fixed ratio of 1:2 (enlarging or reducing). In 1743 Claude Langlois rearranged the design so that it could be used for a range of ratios. Typical 19th and 20th century pantographs have two long arms and two short arms, the short arms being attached halfway along the longer arms such that they and the upper halves of the long arms form a parallelogram. Sliding sockets are provided on the lower ends of the long arms and one of the short arms, in which fit respectively the tracing and drawing points and the pivot. The ratio is adjusted by sliding the sockets to different positions on the arms. Usually they were fitted with castors under the arms to facilitate movement, and the drawing point could be raised and lowered remotely by a cord from a lever at the tracing point.
Also known as: Pentagraph
Hambly, M., 1988, 'Drawing Instruments 1580-1980', Sothebys Publications
Johnston, S., 1998, 'Pantograph', in Bud, R. and Warner, D. (eds), 'Instruments of Science: An Historical Encyclopedia', Garland, New York/London, pp.435-437DR
Parallel Rule
Mathematical/drawing/navigational instrument. A form of rule which could be moved across a drawing or chart for the purpose of drawing parallel lines. Two main types exist: (a) with two or three parallel arms connected by parallel, angled links and, (b) with a roller inset into the rule. Capt. Field’s Improved parallel rules can be of either type and have compass points and degrees marked around the edge for navigational use.
DR
Pebble tester
Pedometer
An instrument for measuring the distance walked by a person, or sometimes a horse. Basically a pedometer comprises three components, namely an actuating mechanism, wheelwork and one or more dials to display distance. Early pedometers were typically actuated by a cord or strap attached to the wearer’s leg but in 1831 William Payne obtained a patent for a pedometer actuated by a pendulum within the case and since then pedometers have been of that type. Many pedometers include a means of limiting the swing of the pendulum to adjust the instrument for the user’s stride. Some pedometers, known as paceometers or passometers, do not convert paces to distance for display but directly display the number of steps walked. These were used for surveying and the user’s stride was measured separately to convert the number of steps to distance, this being more accurate.
DR
Pen (Border)
Drawing instrument. A form of ruling pen for drawing thick lines, having a third member between the two blades to aid ink flow.
DR
Pen (Crow Quill)
Drawing instrument. A writing pen with a fine nib ending at its mounting end in cylinder about 3mm diameter, used for lettering on drawings and maps.
Also known as: Mapping pen
DR
Pen (Curved line)
Drawing instrument. A form of ruling pen in which the pen blades are attached to a rod, which is free to rotate within the pen handle. The blades are usually curved in a gentle S shape to one side so that they will follow the direction in which the pen handle is moved. There is usually a nut at the top of the handle for locking the blades for ruling straight lines. Road pens were also made in the form of double curved line pens.
See also: Pen (Double)
DR
Pen (Dotting)
Drawing instrument. A form of ruling pen for drawing dotted lines. Two basic forms exist. The simpler form has, between the pen blades, a serrated edge wheel for the pattern of dotted line required, which transfers the ink to the paper. Often there is an ink reservoir or feed above the wheel and between the blades, which may form part of one of the blades, and a variety of serrated wheels may be supplied. The other form is mechanical and consists of hinged ruling pen which is lifted up and down from the paper by a serrated wheel which is driven by a second, finely toothed, wheel which is run along the paper or the edge of a scale.
Also known as: Wheel pen, Dotted line pen
DR
Pen (Double)
Drawing instrument. A double form of ruling pen for drawing parallel lines, e.g. a road on a map, the distance apart of the two pens being adjustable by means of a screw.
Also known as: Road pen
DR
Pen (Litho)
Drawing instrument. A form of ruling pen, usually with extra long, fixed blades, used for drawing on lithographic stones.
DR
Pen (Road): See Pen (Double)
Pen (Ruling)
Drawing instrument. A pen used for ruling lines on a drawing, usually having two blades, the distance apart of which can be adjusted by a sliding ring, screw or other means, to set the width of line. Frequently there is also a means of opening the blades for cleaning. Drawing pens with two blades were used by the Romans from the 1st century AD, and re-emerged during the Renaissance.
Hambly, M., 1988, 'Drawing Instruments 1580-1980', Sothebys Publications
DR
Perimeter
Phenakistoscope
Phonograph
Plane-table
Planetarium
Planimeter (Linear)
Mathematical instrument. An instrument for measuring the area inside a closed curve that is too long to be measured by a polar planimeter. It is similar in construction and use but instead of the pole arm there is a pole wagon or a carriage and rail, to which the tracing arm is hinged. The reference is thus a straight line rather than a point.
DR
Planimeter (Polar)
Mathematical instrument. For measuring the area inside a closed curve (a plane figure). The polar planimeter is the most frequently found type of planimeter, so called because its reference is a fixed point or ‘pole’. It was invented by Jakob Amsler in 1854. It consists of two arms connected by a fixed or moveable hinge, known as the pole arm and the tracing arm. The pole arm has at its outer end a pin, which is held firm by the pole weight. The instrument moves about this point. At the outer end of the tracing arm is a tracing point, which is moved around the periphery of the area to be measured. Near the hinge, on the tracing arm, there is a carriage with a wheel in contact with the paper and a gear train to indicating dials and a Vernier. By reading the dials at the start and end of one complete circuit of the figure the area can be easily determined.
DR
Planimeter (Radial)
Mathematical instrument. An instrument for finding the mean radius and hence mean value of circular charts of recording instruments.
DR
Pocoscope
(1) Optical Instrument. Trade name. A type of pocket pair of opera glasses contained in a case resembling a purse, popular in the 1890s. Or (2) Optical Instrument. A type of stereo viewer for use in ophthalmic medical diagnosis or ocular training.
NH
Polarimeter
Polariscope
Polemoscope: See Jealousy Glass
Potentiometer
Power Factor Meter
Electrical instrument for taking direct measurements of the power factor in an alternating current circuit.
RB
Pricker
Mathematical/drawing instrument.A pin or needle used for marking off measurements or angles from scales or protractors. They were available as separate instruments, often with an ivory handle, or were revealed when the handle of a ruling pen was unscrewed. Protracting pins were also placed at the extremity of the arms of Vernier and folding arm protractors. They could also be used for pricking through when copying a drawing.
Also known as: Protracting Pin
DR
Protractor
Mathematical instrument for measuring or plotting angles. The first protractors were made of brass and either circular or semi-circular, and graduated from 0 to 360 degrees or 0 to 180 respectively. Since their introduction in the late 16th century they have been made in a wide variety of materials and forms.
DR
Protractor (Folding arm)
Mathematical/drawing instrument. A circular, Vernier protractor having two arms at 180 degrees to each other, each being hinged above the Vernier, with a protracting pin on the end of the hinged part. They can usually be very accurately set (to one minute of arc) by either a thumbwheel pinion, rotating on a circular rack on the edge of the circle, or by a tangent screw, again acting on the edge of the circle. They were often used for plotting theodolite readings. A magnifier was usually supplied with them for reading the Vernier.
See also: Protractor (Vernier)
DR
Protractor (Rectangular)
Mathematical/drawing instrument. A form of protractor regularly found in sets of drawing instruments made from flat material, such as ivory, boxwood or brass, usually with bevelled edges and typically six inches long by 1¾ inches wide. It is graduated round three sides from 0 to 180 degrees and has a variety of other scales engraved on it.
DR
Protractor (Vernier)
Mathematical/drawing instrument. A circular or semi-circular protractor with one or more arms, pivoted about the centre and having a Vernier scale on the arm(s) which is read in conjunction with the outer degree scale. The end of the arm, which extends as a ruling edge beyond the outer degree scale, is usually terminated with a pin, which can be used to prick out the angle very accurately, the Vernier often enabling the instrument to be set to one minute of arc.
See also: Protractor (Folding Arm)
DR
Q Meter
Electrical instrument for use in radio and telecommunications engineering. It measures the quality factor of an inductor or capacitor at its resonant frequency.
RB
Quadrant
Quizzing glass
Optical instrument. A hand-held monocular lens, often decorative, popular in the eighteenth and nineteenth centuries and used closer to the eye than to the object being viewed.
Also known as: Quizzer, Manocle
NH
Radio
Radiometer
Reading glass
Optical instrument. A hand-held convex monocular lens, usually of large diameter but of comparatively long focal length (usually greater than ten inches) and modest power.
Mills, A., 1997, 'Single Lens Magnifiers, Part I: Reading Glasses', Bulletin of the Scientific Instrument Society 54, pp.29-30
Reading Glasses and Magnifiers
See also: Magnifying Glass
NH
Reflecting Circle
Refracting unit
Refractionometer
Refractometer
Optical instrument for measuring the refractive index and/or dispersive power of a translucent material including those in a gaseous or liquid state. The refractometer was devised for the Carl Zeiss company by Ernst Abbe in 1881 to assist in the production of optical glass of uniform quality. Additional Zeiss models were designed from 1890 for a variety of uses including chemical analysis of fats and oils, for which specialist variants such as the Butyro, Oleorefractometer and Liquiscope were designed. The Zeiss dominance of the market was challenged after the First World War by firms such as Adam Hilger Ltd. As well as their use in quality control, refractometers can be used to identify unknown substances including minerals and gemstones, by reference to their refractive index, or for measuring industrial fluid concentrations. Traditional Abbe Refractometers are still supplied and resemble desk microscopes with easily manipulated focus wheels to the side. Modern handheld refractometers are wedge shaped, often with a monocular eyepiece and may provide a digital reading. Well known manufacturers include Mettler of Switzerland (since 1945) and Atago of Japan (since 1956).
The Evolution of the Abbe Refractometer
Warner, D.J., 2008, 'Instruments for Quality and Process Control', Bulletin of the Scientific Instrument Society 96, pp.4-5
NH et al.
Retinoscope
Saccharimeter
Optical instrument which uses polarised light for measuring the saccharin content of sugar. Experiments dating back to Jean-Baptiste Biot in 1815 had demonstrated that polarised light was rotated differently in various sugars. A specific award-winning polariscope. termed a 'saccharimeter'. was unveiled by JBF Soleil in Paris in 1846 . Other early saccharimeters were produced in Germany e.g. by Franz Schmidt & Haensch. Lerebours & Secretan were producing saccharimeters for use by customs authorities in order to assist in the levy of taxes as early as 1853.
Warner, D.J., 2008, 'Instruments for Quality and Process Control', Bulletin of the Scientific Instrument Society 96, pp.2
See also: Polariscope
Saccharometer
A form of hydrometer used to determine the sugar content of liquids, for instance in brewing.
DR
Sand glass
Time-measuring instrument. Sand glasses have been available as reasonably accurate timing devices since the 14th century. The first reference seems to date from Siena (Italy) in 1337. They generally consist of two slightly conical shaped tubes running into each other at the narrow end and supported vertically by a surrounding frame or suspension hook. The sand or other granular substance (powdered marble, iron filings etc.) runs from one tube the other in a set time, following which the glass tubes can be inverted to start the process over again. Early sand glasses could run for over an hour. Variations include the hour glass (a sand glass measuring the specific time of one hour) and the humble egg timer (in fact crushed egg shells were often used instead of sand for the inner material). A 28-second sand glass was used at sea to measure the speed of the ship in knots. From 1707 Sir John Floyer is known to have used small sand glasses to measure the human pulse. Later in the eighteenth century glass blowers learned to make sand glasses in one piece without the need for a central join.
Balmer, R.T., 1978, 'The Operation of the Sand Clocks and their Medieval Development', Technology and Culture 19, pp.615-632
Turner, G., 1998, Scientific Instruments 1500-1900 An Introduction, pp.13-15
Blaufox, M.D. and Constable, A.R., 2008, 'The Sandglass and the Pulse', Bulletin of the Scientific Instrument Society 96, pp.18-19
The Mechanics of the Sand Glass
NH
Scale (chain)
Mathematical/surveying instrument. A scale rule with scales of chains to the inch, used by surveyors.
DR
Scale (diagonal)
Mathematical instrument. A scale engraved on the face of a rule or protractor, having eleven parallel lines. Each line is divided at intervals of a ¼ or ½ inch and at each end diagonal lines are engraved running across the parallel lines such that they advance one tenth or one fifth of the main division interval. This enables dividers to be set on the finest diagonal scales to an accuracy, in theory, of 1/400 inch.
DR
Scale (letter)
Scale (money)
Scale (opium)
Scale (self-indicating)
Scale (spring)
Scale (triangular)
Mathematical instrument. A scale rule with three faces at 60 degrees to each other. Initially made with the cross-section of an equilateral triangle, the faces were later made concave, so that they would rest better on the paper and present a sharper edge for measuring, and a groove was machined down the centre of each face to make them easier to pick up.
DR
Scale Rule
Mathematical instrument. A rule with scales on one or both sides.
DR
Scales (Marquois)
A pair of thick, double sided, boxwood scales used in conjunction with a special set square having a hypotenuse which is three times the length of the shortest side. They were usually found in sets of drawing instruments for military use.
DR
N.B. This is an updated definition based on original source evidence related to W.F. Stanley & Co.
Scotometer
Sectograph: see Dividers (Spacing)
Sectioner
Mathematical/drawing instrument. A form of set square or parallel rule with an indexing mechanism for drawing closely and regularly spaced, parallel lines, for instance to indicate sectioning on an engineering drawing. A variety of designs were produced, such as Maginnis’s Patent Dead Beat Sectioner.
Also known as: Section liner
DR
Sector
Mathematical instrument. The Sector is a form of jointed rule with graduated scales on it, a number of which radiate from the axis of the joint. These scales enable calculations to be performed, based on the principle of similar triangles, with the aid of dividers. Other scales were used for trigonometry or were logarithmic and could thus be used for multiplication and division. Whilst most English sectors were provided with scales for general mathematical use, French and other Continental sectors were provided with scales for military purposes, such as gunnery or fortification design. Galileo Galilei is credited with developing the sector in Italy c.1598 but the sector was also being developed in England at this time.
Hambly, M., 1988, 'Drawing Instruments 1580-1980', Sothebys Publications
DR
Sector (Architectonic)
Mathematical instrument. A special form of sector with a circular arc, bridging the arms, with additional scales on it, for calculating the elements which make up the five classical orders of architecture.
DR
Set Square
Mathematical/drawing instrument. A triangular piece of flat material, one angle being a right angle and the other angles being typically 45 and 45 degrees, or 30 and 60 degrees. Usually used in conjunction with a T Square for drawing lines at those angles to the horizontal.
Also known as: Triangle
DR
Set Square (adjustable)
Mathematical/drawing instrument. A set square with two faces at right angles and one face for which the angle can be adjusted and set against a scale of degrees.
DR
Sextant
Sextant (bubble)
Sextant (pocket)
Slide rule
Delehar, P., 1984, 'Notes on Slide Rules', Bulletin of the Scientific Instrument Society 3, pp.3-10
Slit lamp
Spectacles
A binocular optical instrument, originally hand-held, which developed over the centuries into a device continually worn on the face. The first spectacles were probably improvised in or before the third quarter of the thirteenth century and were in effect two magnifying glasses rivetted together at the handle. Various shapes of nose spectacles with bow bridges were designed in the following centuries for the correction of the wearer's hypermetropia and, later, myopia. These styles remained in common use well into the second half of the eighteenth century. Sides in the form of temple-pieces with large terminals are now thought to have been invented before 1727 and the earliest spiral type is associated with the optician Edward Scarlett (Senior). From the 17th-19th centuries spectacles may well have formed the mainstay of many businesses more famous to modern historians for their scientific instruments. The Worshipful Company of Spectaclemakers regulated the London 'craft' from 1629. Benjamin Franklin imported English-made spectacles to the American colonies where the McAllister dynasty developed into the most prominent US spectaclemakers. Sunglasses were first popularised in Italy in the 1780s and revived mainly through American influence in the early-mid 20th century. Tinted spectacle lenses for therapeutic and ceremonial purposes were also a feature of the quite separate development of spectacles in China and Japan. In the later 20th century spectacle production consolidated in northern Italy, Austria, the Jura region of France the USA, Japan and increasingly China. At various times spectacles have also been used as mounting devices for other instruments including binoculars, opera glasses and medical diagnostic instruments.
Also known as: glasses (colloquial), eyeglasses (US)
Davidson, D.C. and MacGregor R.J.S., 2002, Spectacles, Lorgnettes and Monocles, Shire Publications
The MusEYEum - Spectacles Gallery
NH
Spectroscope
Austin, J., 'A Forgotten Meteorological Instrument: The Rainband Spectroscope', Bulletin of the Scientific Instrument Society 1, pp.9-12
Bennett, J.A., 1984, 'The Spectroscope's First Decade', Bulletin of the Scientific Instrument Society 4, pp.3-6
Spyglass
Standard Needle
Surveying instrument comprising a needle set in a wooden trough with a glazed top and sighting vanes at each end, used to check the alignement of compass needles in other surveying instruments such as circumferentors and theodolites. They seem to have been used mainly in the survey of New South Wales (Australia) in the 1860s, associated with the maker Angelo Tornaghi
Holland, J., 2008, 'Standard Needles', Bulletin of the Scientific Instrument Society 96, pp.15-16
Station Pointer
A mathematical and navigational instrument first invented by the Admiralty Surveyor, Murdoch Mackenzie and comprising a special form of circular protractor with three long arms radiating from the centre, one being fixed and two movable. Usually they were also equipped with Verniers and tangent screws for accurately setting the arm positions. They were used for accurately determining position on a map or chart from the angles between three distant landmarks, usually measured with a sextant, and were primarily used for precise coastal navigation.
MacKenzie, M., 1774, Treatise on Maritime Surveying
DR
Steelyard
Stereoscope
Sundial
A timekeeping instrument to both measure and record the passing of time.
Surveyor's Wheel
Telegraph
Telephone
Telescope (reflecting)
Telescope (refracting)
Test chart
Thaumotrope
Theodolite
Thermoscope
Thermometer
Thermos flask: see vacuum flask
Tintometer
An optical and chemical instrument for comparing the colour of beer samples through the use of combinations of three coloured filters of various intensities of magenta, yellow and cyan. Patented (UK12867) by the brewer Joseph Lovibond of Salisbury in 1886, it later found uses in many other industries including sugar refining and the dye industry.
See also: Colorimeter
Tonometer
Tourmaline tongs
Transformer
Traverse Board
Trial case
Trial frame
Tracer
Mathematical/drawing instrument. An instrument with a rounded point used for tracing drawings. The best tracers had an agate point but they were also made with steel points.
DR
Triangle: see Set Square
T Square
Mathematical/drawing instrument. A long rule, fixed to an arm at right angles to it, which slides along the edge of a drawing board such that the long rule, usually the width of the board, is always at right angles to the edge of the board and forms a horizontal reference. Versions were, however, produced where the angle of the rule to the sliding arm could be varied and these were popular in the USA.
DR
Typewriter
Vacuum flask
A pneumatic/chemical instrument consisting of a thermally insulating vessel. By cutting off the contents of the vessel from their environmental surroundings their temperature can be maintained. First designed by the Scottish physicist James Dewar (1842-1923) in 1892. Commercially available in Germany under the trademark 'Thermos' from about 1904 for keeping hot drinks warm. Vacuum flasks are used in scientific laboratories to keep gases like oxygen or nitrogen in liquid form.
Also known as: Dewar flask, Thermos flask
James Dewar Collection at the Royal Institution
NH
Variometer
(1) Electrical instrument which measures electrical inductance. Also (2) navigational instrument. A type of pressure gauge which indicates rate-of-climb or descent of an aircraft. Also (3) electrical instrument which measures the horizontal intensity or declination of a terrestrial magnetic field.
RB
Vibrometer
Mechanical instrument that measures the frequency and/or amplitude of vibrations, usually of a machine for example marine engines. Types include the Davey, Kelvin and Schenk vibrometers. The piezo-electric stylus cartridges formerly used on record players represent another application of the vibrometer principle. Non-contact vibrometry is now carried out by laser interferometers.
Also known as: Contact Vibration Sensor
Vicat Tester
An instrument that measures the degree of set of cement paste by the amount of penetration of a weighted test needle.
RB
Viscosimeter
A chemical instrument for measuring viscosity. Although they had a use in evaluating the gum water used in chemical dyes for the textile industry no less a figure than Sir William Crookes dismissed them as overly complicated. In the mid 19th century James Nasmyth designed an instrument to measure the viscosity of lubricating oils. This device consisted of a grooved plate that could be inclined to any set angle. Efflux viscosimeters measure the time taken for fluids to empty from containers and have been around since at least the mid 1880s, the Ubbelohde design from 1909 remaining in use in many European countries.
Warner, D.J., 2008, 'Instruments for Quality and Process Control', Bulletin of the Scientific Instrument Society 96, pp.3-4
Also known as: viscometer
Volt meter
Weather-glass
X-ray
Yardstick
Zoetrope
Zograscope
Zoogyroscope