Q-Z

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Q

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.

Quadrant

Quintant
Navigational/surveying instrument, a quintant performs the same functions as a sextant and is of a similar appearance, but has a slightly longer scale to measure larger angles – up to about 150 degrees. Like the sextant and octant, it works on the principle of double reflection to measure the angular distance between two bodies by bringing the reflected image of one object alongside that of the other viewed directly.

Morzer-Bruyns, W.F.J., 2009, Sextants at Greenwich, OUP/National Maritime Museum, Oxford and Greenwich

R

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

S

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.

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

Sat-Nav
An electronic device used commonly in vehicles from the mid 2000s for route finding and identifying one's location using the global positioning system (GPS), a worldwide radio navigation system based on a string of American military satellites. In common with many technologies it was available to the military many years before it was made over for civilian uses. Motoring sat-navs rely, however, on up-to-date travel software and have been also been blamed for traffic accidents where motorists have unthinkingly followed the voice instructions.

Scale (chain)
Mathematical/surveying instrument. A scale rule with scales of chains to the inch, used by surveyors.

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.

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.

Scale Rule
Mathematical instrument. A rule with scales on one or both sides.

Scales (letter)

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.

N.B. This is an updated definition based on original source evidence related to W.F. Stanley & Co.

Scales (money)

Scales (opium)

Scales (self-indicating)

Scales (spring)

Scanner
A radio device for monitoring a range of frequencies. Scanners used to listen into police radios have proved controversial. More latterly the term scanner has been more associated with a device used in computing to capture digital information and read the image onto the computer. Such scanners can be used to reproduce photographs or elecrtronically record and analyse data such as mutliple choice answers on exam papers.

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

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.

Also known as: compass du proportion (Fr), proportionalzirkel (G)

Hambly, M., 1988, 'Drawing Instruments 1580-1980', Sothebys Publications

Cowham, M., 2009, ‘The Sector’, Bulletin of the Scientific Instrument Society 103, pp.6-13

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.

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

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.

Sextant (marine)
Navigational/surveying instrument that takes its name from its shape: a sixth of a circle. It works on the principle of double reflection, like the octant (q.v.), to measure the angular distance between two bodies by bringing the reflected image of one object alongside that of the other viewed directly. Typical measurements with a sextant would include the altitudes of celestial bodies such as the sun and moon above the horizon, and the angular separation of different celestial or terrestrial bodies (e.g. in surveying). Because the instrument works by double reflection, it can measure angles up to about 120 degrees. The marine sextant was developed in about 1757 by Captain John Campbell with the help of the London instrument maker, John Bird. During trials of the lunar distance method for determining longitude at sea, Campbell first worked with a reflecting circle developed by the German astronomer, Tobias Mayer. Finding this rather cumbersome, Campbell suggested the sextant as a more manageable alternative. Following its introduction, the sextant became one of the principal instruments used on ships for celestial navigation.

Morzer-Bruyns, W.F.J., 2009, Sextants at Greenwich, OUP/National Maritime Museum, Oxford and Greenwich

Morzer-Bruyns, W.F.J., 2006, 'Octants and Sextants in the Musée national de la Marine in Paris: A Report’, Bulletin of the Scientific Instrument Society 88, pp.41-5

Wikipedia: Sextant

See also: quintant

Sextant (bubble)

Sextant (pocket)

Slide rule
A calculating instrument consisting of two or more members with logarithmic scales on them that can be moved relative to each other so that multiplication and division can be performed by setting the scales to the numbers to be multiplied or divided. Slide rules can take several forms of which the most common are linear, circular and spiral. They may also contain many other scales, for instance trigonometric and log-log. The invention of the slide rule, in both linear and circular forms, is now generally attributed to the Rev. William Oughtred in 1624, a logical development from the logarithmic scale invented by Edmund Gunter about 1620. This followed the invention of natural logarithms by John Napier, published in 1614, and the development of logarithms to the base of ten by Henry Briggs.

Delehar, P., 1984, 'Notes on Slide Rules', Bulletin of the Scientific Instrument Society 3, pp.3-10

Cajori, F., 1994, A History of the Logarithmic Slide Rule and Allied Instruments, Astragal Press - originally published in 1909

von Jezierski, D., 2000, Slide Rules A Journey Through Three Centuries, Astragal Press - translated by Rodger Shepherd

Hopp, P.M., 1999, Slide Rules Their History Models and Makers, Astragal Press

The Oughtred Society - History of Slide Rules and other Calculating Instruments

SIS Member David Riches writes: In slide rule collecting circles it is generally accepted that at least one of the scales must be logarithmic, otherwise it would just be a measuring rule with a sliding member or a slide chart. It must also be possible to carry out multiplication without using dividers, thus excluding Gunter rules and sectors.

Slit lamp

Sonic Screwdriver
(Fictional). An electronic instrument associated with the lead character in the long-running BBC television science-fiction series 'Doctor Who'. As such its invention can be assigned to the screenwriter Victor Pemberton. It first appeared on screen in 1968 wielded by the Second Doctor (the actor Patrick Troughton) and over the years, as well as turning screws, it has used sound waves to unpick locks (except for wooden doors), served as a remote communication device with the Tardis, a radiation detector, an amplifier and ignition device. It is the closest the thing the Doctor has to an offensive weapon. The original screwdriver was destroyed in 1982 but a new telescopic version was premiered in 1996. The version seen on screen since 2005 has a blue light. Toy versions produced as promotional merchandise use this feature as an ultra-violet torch.

Diagram of the first generation Sonic Screwdriver

Sonometer

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 Spectacle Makers 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

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

Steelyard
Weighing instrument. A form of balance in which the arms of the beam are of unequal length, but unlike the less common bismar (q.v.) the point of fulcrum is fixed and it is the counterpoise weight which is movable along the longer arm on which a scale is marked. The load to be weighed is suspended from the shorter arm either by a hook or in a pan.

Stereoscope

Sundial
A timekeeping instrument to both measure and record the passing of time. Sundials can be fixed or portable and can be classified further by various means including the design of gnomon, material of manufacture, national or regional variant. The British Sundial Society uses the following classification for fixed sundials although the headings are not always easily applied:

1 Altitude
2 Analemmatic
3 Azimuth
4 Equatorial
5 Equiangular
6 Horizontal
7 Incl/Recl
8 Multiple
9 Noon mark
10 Other
11 Polar
12 Scaphe
13 Spherical
14 Vertical (S)
15 Vertical (N)
16 Vertical (E)
17 Vertical (W)
18 Vertical (D)
8A Mult Facet Head
8B Mult Composite Facet Head
8C Mult Cube/Prism
8D Mult Cube Market Cross
8E Mult Diptych
8F Mult Obelisk Complete
8G Mult Obelisk Partial
8H Mult Lectern with Star
8J Mult Lectern no Star

Cowham, M. (ed.), 2005, Sundials of the British Isles

British Sundial Society - The BSS Sundial Glossary

When Time Began - The History and Science of Sundials

Surveyor's Wheel

Switch
A passive electronic device that passes or blocks electric current.

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T

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.

V

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

Sir James Dewar

James Dewar Collection at the Royal Institution

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.

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.

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

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