# London Museums

### British Library

The British Library was separated organisationally from the British Museum in 1972. It has now moved from the British Museum to a new building in Euston Road by St Pancras Station. A new version of Paolozzi's Newton monument (1995) was made for it and unveiled on 10 Sep 1997. The Library is the second largest in the world, with an estimated 18 million books.

There are a number of sculptures of mathematical interest at the British Library in addition to Paolozzi's Newton. As you walk from the cloakroom to the lockers, you pass Patrick Hughes's disconcerting Paradoxymoron (1996). (A similar work displayed in a shop window in Charing Cross Road a few years ago posed a serious danger to the lives of passers-by who were tempted to step back into the road while looking at it. The BL's one is safer, and for me is the most effective of this series that I have seen.)

As you enter the Library you pass Bill Woodrow's Sitting on History (1995) (not particularly mathematical but fun nevertheless), and in the Piazza Antony Gormley's Planets (2002) has recently been installed: its "eight, one-tonne granite boulders carved with the outlines of a variety of human bodies in the act of clinging onto them" may allude to astronomy. [1]

### British Museum

The British Museum is in Great Russell St Its origins are in the collections of the Royal Society, which were transferred to Montagu House, designed by Hooke, c1674. It was greatly expanded by the collections of Sir Robert Cotton (d. 1631), presented by his grandson in 1700. But the greatest impetus came when the collections of Robert and Edward Harley (1st & 2nd Earls of Oxford) and Sir Hans Sloane (over 100,000 items) became available in 1753, leading to the formal creation of the Museum by an Act of Parliament and a lottery to raise the necessary funds. At present, it is estimated that the Museum contains some 6,500,000 items, though this counts probably millions of fragments. The number of visitors is less certainly estimated at 6,500,000 per year.

Although the Museum has a very small percentage of items of mathematical interest, this still comes to quite an number of items. The items of interest are spread throughout the Museum, but the largest number are in the Egyptian and Western Asiatic Antiquities sections and in the King's Library, which are not very close. Because most of the Museum is a quadrangle surrounding the great Reading Room (now the centre of the Great Court), there is a basic circular route, which I will describe anticlockwise from the Main Entrance.
(I have read of a number of items are in the Museum, which recent enquiries have not been able to locate. This may be because the object is only a fragment, or because the description was made by someone outside the Museum and was either garbled or is not recognised by the Museum, or because the description or dating has changed, or because it is in a different Department than expected or because someone has interpreted 'a museum in Britain' as 'the British Museum', etc. . . )

(This and the next paragraph were written before the move of the British Library to St Pancras.)

To the right of the Entrance Hall are the British Library Galleries. The Manuscript Saloon (Room 30) which has numerous cases displaying early Bibles, the Magna Carta, etc. In English Literature case 8 is the manuscript of Alice's Adventures Under Ground, the predecessor of Wonderland. Lewis Carroll made this up for Alice for Christmas 1864. (The manuscripts of Wonderland and Through the Looking Glass do not exist, but a copy of Wonderland which Carroll made for Alice is in the New York Public Library.)

In the Maps & Views case is a c1300 copy of Planudes' version of Ptolemy's world map, which estimates the circumference of the world as 18,000 miles.

In the Medicine & Science case is a letter of 13 Dec 1670 from Newton to Hooke about falling bodies. (Beside it are notes of Alexander Fleming about a penicillin experiment and two 15C physician's calendars.)

In Room 30a are illuminated manuscripts including a mid 15C version of Boethius's De Consolatione Philosophiae - Boethius's version of Pythagorean arithmetic and number theory was the major arithmetic text book from the 5C to the 12C.

Just beyond half way up the King's Library (Room 32) on the left is a case on early printing containing four examples of what is probably the earliest printing, produced in 764-770. In the centre aisle are fine celestial and terrestrial globes made by George Adams for George III in c1765.

At the end of the Library are a bust of Joseph Banks and the terracotta model of the head of Sloane for the statue in the Entrance Hall.

(The Library also has a vast number of manuscripts and the manuscript reading room has day passes. I have examined Charles Babbage's notebooks here.)

Going out of the end of the King's Library, up some stairs and along Room 33b, one gets to the Oriental Gallery (Room 33). Halfway along this is a exit to a staircase and the North Lift.

If you now go down to Level 1, a display case by the lift shows several Indian board games. The John Addis Gallery of Islamic Art (Room 34) has several scientific instruments. The most prominent is the astrolabe of Shah Sultan Husayn of Persia, made and signed in 1726. It is in case 2, facing the entrance. This was in Sloane's collection in 1753-Husayn was deposed shortly after 1712, the new rulers sold off his possessions, and Sloane just happened to have an agent in the area! Case 10 has a number of gaming pieces and chessmen from 10-11C Egypt and 8C Persia. Case 39 has an elaborate box of scales and mathematical instruments-compasses, dividers, etc., from c1840. Case 45 'Science & Magic' contains an geomantic instrument of c1242 which has a number of dials. On the other side are several astrolabes and quadrants from the 13-17C, two celestial globes, one from c1431 Persia, and a number of weights. (As a mathematician, I find some Islamic art aesthetically satisfying and this new gallery has greatly expanded the amount on show.)

Now going up to Level 3, we get to the smaller Egyptian and Western Asiatic rooms.

The Museum has the Rhind Mathematical Papyrus composed c-1800 and copied c-1575. This is the most important source of our knowledge of Egyptian mathematics. It is in two parts, one about twice the length of the other, with fragments from the break being in New York! The front of the longer part is on display on the south wall of the Third Egyptian Room (Room 62). It reads from right to left, with the headings of problems in red. At the right end are fragments of problems 1-5, then problems 6-40, a blank space, and then problems 41-60. Problem 48 shows a circle in a square and computes the area of the circle as ${({{8}\over{9}})d}^{2}$, corresponding to π = 256 /81 = 3.16049. Toward the left end are several diagrams of triangles which are area problems and at the left end are diagrams of pyramids where simple computations involving the slope are done. It is in hieratic, which is a handwritten priestly script and not too easy to read, though some numbers can be made out.

The Mathematical Leather Roll (c-1700) was nearby (case 126?), but is no longer on display due to its light sensitivity. The Abu Sir Papyrus of c-2500(?) is here. If the date is correct, it is the oldest document on papyrus and the world's oldest book. Two parts are on display in Room 62, case 125 and Room 63, case K. It is basically a list of payments to a temple and one can read numbers in the simpler hieroglyphic forms. Still in Room 62, case 116 has the wonderful painting showing animals playing some board game, dating from c-15C. I have read that the oldest known sundial, from c-1500 Egypt, is in the Museum, but it has not been traced (a call to the horological section obtained the response that he thought it was only a fragment).

In Room 63, case J "Scribes and Artists" shows stones prepared for carving with squared grids drawn on them. Case K "Script Development" has the second piece of the Abu Sir Papyrus. Case L "Mensuration" displays weights and measures, including some measures from c-1300 and item 6025, a measure of length 2 cubits (1050 mm = 41.34 in) divided into 14 palms, but of uncertain date. I have read that the oldest(?) known measure - a 41.46 inch measure divided into cubits, left in a temple at Karnak, c-1400 - is in the British Museum, but there is no record of it; this may be a garbled description of this last measure.

At the top of this case is a piece of a clepsydra (a water clock) from c-320. Also in Room 63 is case C "Toys & Games" with several types of dice and markers, versions of Senet and Tjau, the Egyptian board games from c-15C, a stone board marked with a 3 × 4 diagram and nine stone men, probably used for some ancestor of Noughts and Crosses or Three Men's Morris and dating from >-850.

At the end of Room 64 is an actual piece of the Great Pyramid of Khufu (= Cheops), c-2580, clearly showing the slope and the high precision of the workmanship. In case 9 is a spiral game board for Mehun, c-2700, and several game pieces.

The common term 'Babylonian' is presently out of favour with scholars as it only refers to part of the area and part of the time of the Middle Eastern civilizations. The Museum uses the term 'Western Asiatic'. In the Early Mesopotamian room (room 56), case 3 is devoted to early writing. Just to the left of this is a poster and picture showing what is now considered to be the origins of writing, the use of marks on clay envelopes to record the number and types of tokens inside. These tokens might represent taxes paid: e.g. if one paid three sheep, one received three tokens representing sheep. The clay envelope protected them, but made it impossible to see what was inside, so later the envelope would be marked with three symbols depicting sheep. This took place about -5000/-4000(?). In the case are examples of cuneiform tablets from about -3500 with substantial writing and lots of numbers, since most of these are records of taxes, inventories, etc. These used the older rounded stylus to make units as circles and tens by tilting the stylus to make a D-shaped depression. Recent research by a team of mathematicians and archaeologists has revealed that there are several systems of numerical marks-different symbols were used for different types of object. In case 21 is a round tablet (WA 18039) which records a land survey. It has a number of gaps and examination of similar tablets has shown that the numerical values were written in by a different person than the writer of the text. On the other side of the case is a huge tablet (WA 15285) of c-1800 with geometric diagrams dealing with volumes, a tablet of lunar eclipse omens, a medical tablet on skin problems, c-1900, and a nice set of weights. Further on is one of the famous 'Flood' tablets, from c-1635. Nearby case 16 has the Royal Game of Ur, a board game known from c-2600.

In Room 55, Case 15 is a -6C conversion(?) table for a water clock. Case 10 has one of the famous 'Flood' tablets from the Royal Library of Nineveh, -7C, on display. There are also some circular planispheres, probably astrological tablets, from c-700. (It may be worth noting that Babylonian astrology was almost entirely concerned with national affairs - e.g. a comet might signify the death of a king or an invasion. A few birth horoscopes were made, but the only interpretation was that the stars were good or bad. There is really no trace of the modern form of astrology in Babylonia, despite the claims of modern astrologers. Indeed the casting of a ruler's horoscope was considered a treasonous activity well into the 17C and Pope Sixtus V (in 1586) and Urban VIII (in 1631) prohibited astrological judgements about the Church or the Pope. During the pontificate of Urban VIII (1623-1643), a Father Morandi predicted the Pope would die in 1630 and this was so widely circulated that many cardinals came to Rome in anticipation of a conclave. The only result was that Morandi was imprisoned.) Case 10 also has two tiny ivory numerical tables in the shape of cubes, from -7C. Case 15 has a crude map of the world from c-600.

(Mackinnon describes several mathematical cuneiform tablets in Room 55 but these were removed in the recent rearrangement, but they may reappear sometime, so I will describe them briefly. BM 92698 was the first numerical tablet deciphered by Rawlinson; it is a table of squares, square roots and cubes. BM 13901 is a compendium of quadratic equations. BM 80150 and BM 77951 are tables of reciprocals. BM 85194 has a problem dealing with a circular city, with a diagram. 13901 and 80150 and a tablet similar to 92698 are illustrated and discussed by Mackinnon.)
In Room 52, Case 6 contains an astronomical diary (-4C) and an eclipse table (-330). Case 25 contains an ephemeris for the moon (-103), a description of Halley's comet (-164) and an almanac (+61). (The curator said he uses negative years adjusted for the lack of a year 0, i.e. 1 BC is year 0, 2 BC is year -1, etc. I think most people use -2 for 2 BC.) Case 24 has a ceramic board (WA 1991-7.20,I) for a kind of snakes and ladders from c-1000. The label says this game was popular during the second and first millennia BC.

At the south end of the east side, passing through the rooms closed for renovation, we get to Medieval and later material. Room 41, Case 52 has some gaming pieces. Room 42, Case 3 has the famous Lewis Chessmen and many other gaming pieces or counters from 10-12C, mostly in ivory. The Museum has 67 of the Lewis Chessmen and the 14 plain draughtsmen, dating from c1150, found on the Isle of Lewis in Scotland in 1831. I only saw 43 Chessmen and 4 draughtsmen when I visited. Case 12 "Secular Life" contains several astrolabes, quadrants and measures. One astrolabe is English from c1295 and was part of Sloane's collection. There is a 1326 English astrolabe, the earliest known dated scientific instrument from Europe, and the 1342 Blakene Astrolabe, the earliest known dated and signed scientific instrument from Europe. Room 43, Case 5, item 6 is a 13C puzzle jug, but it had been removed when I visited. Room 43 has a number of nice tessellated pavements.

Room 44 "Clocks and Watches" has probably the world's best collection of time keepers, though Harrison's famous marine chronometers are mostly at the Old Royal Observatory, Greenwich. The earliest surviving clocks date from the end of the 14C (the Science Museum has the works of the Wells Cathedral clock of c1390 and this is still running!). Room 44 begins with a model of the escapement of the great clock of Richard of Wallingford. He was the father of English trigonometry. In 1327-1336, he was Abbot at St Albans Abbey and started construction of a great astronomical clock, the first clock to be clearly described. It was completed about 1356. The room displays the development of clocks, often with models illustrating the escapements, and illustrated with pictures of notable clockmakers. Perhaps the most fascinating clock is the famous rolling ball timepiece of Sir William Congreve, patented in 1808 and built c1810. There is also a case of various mathematical instruments from the 16-17C.

Room 46, case 6 contains an astrolabe of Henry VIII, c1540, a quadrant of Edward VI, from 1551, and the relics of John Dee. Dee wrote the famous Mathematical Preface to the first translation of Euclid into English, by Henry Billingsley in 1570. Dee was sort of court astrologer to Elizabeth I and increasingly dabbled in magic and alchemy as he got older. The case shows Dee's 'Magic Mirror', a piece of Aztec obsidian later owned by Horace Walpole, who wrote the inscription on the back of the mirror's case. In 1605, the fame of Dee's Magic Mirror was so great that it was popularly supposed to have revealed the Gunpowder Plot. There are also a crystal ball, an amulet and three inscribed wax discs to support his magical table. The Museum also has Dee's own catalogue of his library of 4000 books, perhaps the finest in Europe at the time, but this is not on display. Dee may have been the model for Prospero in Shakespeare's Tempest. There is Roubiliac's plaster model for a bust of Richard Bentley (1662-1742), one of the first expositors of Newton's physics in 1692-1693. He became Master of Trinity College, Cambridge, in 1700 and strongly encouraged mathematics. He had an observatory built for Roger Cotes in 1706 and sponsored the second edition of Newton's Principia, edited by Cotes, in 1713. He also seems to have introduced written examinations in 1702.

Room 47, cases 12, 16 and a nearby wall case contain tiles by William de Morgan, the famous potter son of Augustus de Morgan, first professor of mathematics at University College London in 1828-1831 and in 1836-1866.

Going to the south on the west side of the Museum, Room 72 "Ancient Cyprus", case 8 has a game board from c-12C. Going to the south end, Room 69 "Daily Life", case 9 has a number of games. There is a 3 × 3 array of holes in a stone board, probably used for some sort of three-in-a-row game. It comes from Ephesus, C1-3. There are also lots of different types of dice and similar objects. I have a note that the Museum has dice in the shapes of all the Platonic solids, but only cubes, an icosahedron and two cubo-octahedra are presently on display. I have a note that the Museum has one of the five known Roman hand abaci, but the Greek and Roman Department could not trace it. I managed to locate it by calling the Horological Students' Room, which has it, but the catalogue entry says it is Roman type, probably 18C, which would explain why the Greek and Roman Department knows nothing about it! Case 25 has weights and scales. Cases 26 & 30 have instruments used by artists and sculptors-dividers, squares, proportional compasses, etc.

Going down the West Stairs or the Main Stairs, go to the Main Egyptian Gallery (Room 25). The Rosetta Stone of -196 is towards the south end. It was uncovered by the French expedition to Egypt in 1799 and brought to England in 1802. The inscription is given three times: in hieroglyphic, demotic and Greek. The physician and mathematical physicist Thomas Young began its decipherment in 1814-1818, which Champollion completed in 1821-1822.

Room 3 contains Archaic Greek material, which includes lots of geometric ornament. In Room 14 is a Greek portrait bust of Socrates. In the basement beneath this area are some rooms of miscellaneous sculpture and art. Room 89 has a fine set of 13 Assyrian weights in the form of crouching lions, from c-8C.

### Science Museum

The Science Museum in South Kensington is probably the world's greatest museum of science and technology, with over 200,000 items. It became independent in 1909, having previously been part of the Victoria and Albert Museum. The Patent Office Museum was incorporated in 1884. As in any great museum, exhibits and galleries are constantly changing. I haven't checked the current state of most galleries. Also, not all items may be on display-I have frequently seen items in special exhibitions or described in the literature which are not usually on display. The former gallery numbers are no longer used.

The Museum is built on the site of a maze designed by William Andrews Nesfield for the Royal Horticultural Society's garden in Kensington, opened in 1861; his plan for it, and a bird's-eye view that shows the maze in the southwestern corner of the garden, are in the RHS Library. The garden was abandoned in 1888 and subsequently built over, with the Science Museum occupying the southern part of the site - including, but not limited to, the maze site. Some sources name Prince Albert in connection with this maze: he was the President of the RHS at the time of the garden's design, so could in a sense be said to have commissioned it. (We are grateful to Brent Elliott, Librarian of the Royal Horticultural Society, for correcting the previous inaccurate version of this paragraph - Tony Mann October 2002])

It is also on the site of the Solar Physics Laboratory which operated under Norman Lockyer from 1879 until 1913. In the Festival of Britain, 1951, a Ferranti Nimrod Nim-playing computer was put on display here and played Nim with piles of 3, 5, 6.

In 1975, the Museum opened a mathematics and computing gallery, then called Computing Then and Now but subsequently renamed. This is not a very dynamic display compared to the Exploratorium or other US museums, but it contains several items of three-star interest.

Primarily, there are Charles Babbage's sample Difference Engine of 1833 and his incomplete Analytical Engine. The Difference Engine, using second differences so it can compute a quadratic, is in a large new gallery called Making the Modern World. It comprises about 1/7 of the planned version which would have had 25,000 parts. They also have Donkin's 1859 copy of Scheutz's Difference Engine No. 2 of 1853, based on Babbage's ideas. This was used to compute the English Life Table in 1864. They also have most of Babbage's drawings and his 'Scribbling Books' and many sample pieces, dies, etc., though not all of these are on display. Babbage's son, General H. P. Babbage, built a mill for the Analytical Engine after his father's death, but it did not work dependably - this is also here.

In the early 1990s, to commemorate the second centenary of Babbage's birth, the Science Museum constructed Babbage's Difference Engine No. 2, which Babbage designed in 1847-1849 but never attempted building. It has about 4000 parts, is about 11' by 6' by 1' (3.4m by 2.1m by .5m) and weighs about 3 tons. It has 7 orders of differences (the 7th being settable to a constant value, so it could compute a 7th order polynomial) and 31 decimal places. This is the centrepiece of an exhibition on Babbage in a special exhibition area at the front of the Gallery. At one time it was being demonstrated twice a day, but is now only done by appointment. On 25 Nov 1993, the Difference Engine was raced against a Canon BN22 Notebook PC in calculating a seventh order polynomial. The Difference Engine got 9 results out before the Canon began printing, but then the Canon produced 50 values before the Difference Engine got another result!

All the other Babbage and related material from the Science Museum is now here, including a woven silk portrait of Jacquard, (but not the one owned by Babbage, whose whereabouts is unknown). It required 24,000 punched cards, each having 1050 positions.

The gallery also contains the following:

Replicas of cuneiform tablets, replica of the Salamis counting board, replica of a Roman hand abacus, replicas of the machines of Schickard and Pascal and a demonstration of Leibniz's stepped wheel and barrelled wheel.

Morland's 1666 calculator which basically added and subtracted. This is not to be confused with his multiplying calculator, of about the same time, probably the first successful multiplier, though it was just a mechanization of Napier's bones.

Stanhope's second calculator of 1777, and a trial piece for it. This multiplied and divided, using Leibniz's barrelled wheel.

Many other calculators are shown, some in cut-away forms. The wall continues with the history of punched cards and then moves into computers: an original Hollerith punch; Kelvin's Harmonic Analyser (1878): parts of Hartree's Differential Analyser and its Meccano model (1935); counters from the Harvard Mark I (c1943); a segment of ENIAC (c1945); a replica of the first transistor (23 Dec 1947) (no longer on display); some parts from CADET, one of the first experimental transistorised computers, built at Harwell in 1952-1957, showing that the early transistors were too delicate to be soldered into place and had to be clipped into circuitry; Mercury delay lines from EDSAC, LEO 1 (1948) and the Pilot ACE. Nickel delay line from an Elliott machine; copies of the first EDSAC output (a table of squares); most of the Pilot ACE computer (1950) is now in Making the Modern World, but the slow speed ACE simulator of 1960 is here; Williams cathode ray storage tube from the Ferranti Mark I; A. D. Booth's original model of magnetic drum storage; 1024 bit core plane from Whirlwind (1953); bits from ATLAS and COLOSSUS; counters from the Harvard Mark I; a PDP-8; a core plane from an IBM 1401;.the program for the First British Computer Exhibition at Olympia, 28 Nov - 4 Dec 1958; a prototype of ANITA, the first commercial electronic calculator of 1961, designed by N. Kitz for Sumlock Comptometer.

In 1995, a restored version of Bill Phillips' 1949 economic model analogue computer using water flow to represent money was put on display (see London School of Economics). It is still in operation occasionally, and a brief video shows it in operation.

Another recent addition is an example of the MAC (Mechanical Analogue Computer) developed by Air Trainers Link Ltd in 1958. The example is a simplified version used for teaching at Imperial College. It could deal with 4th order differential equations.

Other mathematical items are the following:

Some tally-sticks from the British Exchequer; some early examples of Napier's 'Bones' donated by a descendent of Napier - one box claims to have belonged to Napier (though I haven't seen this on display); the earliest known straight slide rule (1654); Sir Samuel Morland's Trigonometer (1664); a set of brass framework regular polyhedra thought to be Robert Boyle's-this is now in Science in the 18th Century.

Clement's Ellipsograph (1818); Perigal's Compound Geometric Chuck, which drew Lissajous figures in 1835, over 20 years before Lissajous did; a pantograph of Galton's (1869); Boys's Integraph (1881); a Conchoidograph and a Parabolagraph; numerous planimeters; a collection of superbly made uniform polyhedra, one of the few complete sets; a display of surface models from the 1860s to the present day, including a set of complex Klein bottles in glass; a remarkable collection of other slide rules and drawing instruments.

Other current galleries of interest are listed below, in alphabetic order, after a few extra items.

The stairwell in the middle of the Museum has a Foucault pendulum, using a new design by Brian Pippard.

In the new Wellcome Wing is 'Launch Pad', a most successful 'hands-on' exhibition area.

The Navigation Gallery contains a number of old items. There is a quadrant of 1748 by Benjamin Cole, 1748, which includes a vernier-one of the first uses of this device. It used to have a John Bird sextant of 1772, said to have belonged to Captain Cook, but this is now in the Whitby Museum.
The Nuclear Physics & Power Gallery has several items relating to mathematical and experimental physics.

There is a new Picture Gallery which displays some of the more important of the Museum's pictures. The Epstein bust of Einstein (another copy is in the Tate Gallery) , a portrait of Stephen Hawking, a picture of the Stephenson family and one of Watt were the most notable when I visited in Oct 1996. P. J. de Loutherbourg's famous painting 'Coalbrookdale by Night' of 1801 is in Making the Modern World.

In Nov 1993, a new exhibition area, Science in the 18th Century, was opened to display part of the George III Collection of about 1000 scientific instruments and devices built for George III in 1760-1762, collected by Stephen Demainbray in the 1750s, and related items of the 18-19C. The collections of George III and Demainbray came together in 1769 when Demainbray was appointed Superintendent of the King's Observatory at Kew. The collection was given to KCL and then to the Science Museum in 1927. It has the original orrery made by John Rowley (c1713) for Charles Boyle, 4th Earl of Orrery. This device is on loan from the Earl of Cork and Orrery. It only shows the movements of the sun, earth and moon. A Grand Orrery, made in 1733 for George II by Rowley's successor Thomas Wright, shows the other known planets and the moons of Jupiter and Saturn. It also has some of Boyle's geometric models, an armillary sphere, a cycloidal pendulum, devices for showing the paths of projectiles, devices for demonstrating collisions, a machine to show Newton's second law, and many other physical and chemical devices. There is an air pump built by Francis Hauksbee, c1705 and Magdeburg Hemispheres made for George III in 1761. I noted James Six's prototype recording maximum and minimum thermometer of 1782. Adams prepared two manuscript instruction books for the pneumatical and mechanical devices. The excellent and well-illustrated catalogue of this Collection is available: Public and private science, by A. Q. Morton and J. A. Wess, OUP 1993.

The Surveying Gallery has a few items of interest. Jesse Ramsden made two three foot theodolites made for the Ordnance Survey in 1791 and the surviving one used to be here but is now in Making the Modern World. There are examples of the modern GPS (Global Positioning System) devices and Luke Howard's original rain gauge.

The Telecommunications Gallery has a non-mathematical panel on the mathematical analysis by Heaviside which led Pupin to correct the distortion of speech in underground cables. There is also a circuit board from a Leo III (1962).

The Time Measurement Gallery has portraits of Huygens, John Harrison and Thomas Earnshaw. It had a statue of Galileo studying the pendulum, now in store. It has model clepsydras, an alarm hourglass(!) and a fine display of sundials. There is a model of Su Sung's water powered astronomical clock of 1088. There is a modern version of the Artrarum (Astronomical Clock) of Dondi, 1364-1381. The works of the Wells Cathedral clock, c1390, are here and running, with striking bells attached; as are: a replica of Brahe's quadrant; a 1659 drawing by Viviani of Galileo's idea for a clock and modern examples of Galileo's pendulum clock (from 1833); replicas of Huygens' pendulum clocks of 1658 and 1678 which used cycloidal cheeks to produce a period independent of amplitude; a c1658 clock by Salomon Coster, the earliest spring-driven pendulum clock in Britain ; a reconstruction of a Hooke experiment on long pendulums. One of Harrison's early wooden clocks is in the Museum, though it is not running. He made it in 1715 and all parts are wooden except one wheel and the axles and bushes.

Some galleries have now vanished, but I list some of the interesting contents below as these items tend to reappear in other galleries or in special exhibits.

Some of the material from the Astronomy Gallery can be found in other galleries: Geophysics & Oceanography, George III, Navigation, Optics, Time Measurement, Surveying. It contained the orreries, now in the George III Gallery. It had two telescopes of William Herschel, one of which is probably the one used to discover Uranus, though it is not sure which, if either - Caroline Herschel's telescope is in Making the Modern World, and another 7 foot Herschel telescope is in Science in the 18th Century. There was a portrait of Galileo and a lens used by Flamsteed. The Museum also has Bradley's 1730s model illustrating his theory of the aberration of light and an astronomical quadrant made for the Transit of Venus expedition in 1769 and said to have been taken on one of Captain Cook's voyages, but I don't remember seeing these (a quadrant is in Optics, another in Making the Modern World). A 1971 booklet says the following are also in the Museum: copies of Galileo's telescopes (this is in Space and Optics); copy of Newton's second telescope of 1671; the first successful Gregorian telescope, made by John Hadley in 1726; James Nasmyth's 20 in. reflector of 1842 which he used to produce The Moon (these last three items are not on display at present). A model and the 6 ft. mirror of the Rosse telescope at Birr Castle (and some eyepieces) are on the third floor, near Science in the 18th Century. (Although the present (seventh) Earl of Rosse would prefer the mirror to be returned to Birr [2].) Isaac Roberts' 20 in. reflector which first showed, in 1887, the spiral form of the nebula in Andromeda is not on display but can be seen by appointment.
What used to be called the Domestic Appliances Gallery, in the Basement, is now Secret Life of the Home. It had some interesting locks, now in the new Wellcome Wing: puzzle locks, an early version of J. N. Maskelyne's penny in the slot lock and the famous Bramah lock, made by Maudslay in 1801, which had a 200 guinea prize for anyone who could pick it. Hobbs, the famous American locksmith, finally picked it in 1851 after 16 days work.
The Electricity & Magnetism Gallery, now closed, had some material and a bust of Maxwell. Its Enigma cipher machine is now in Telecommunications.
The Textile Gallery used to contain examples of Falcon (1728), Vaucanson (1745) and Jacquard looms - the original punched card devices, dating back to 1728 (though the Vaucanson device has a perforated drum). The Falcon machine was built by Falcon himself in 1738 for a UK patent and it still runs. Only the Jacquard loom is still on display, in Making the Modern World. The woven silk portrait of Jacquard which was here is now in the Computing Gallery.

Here is a list of other significant mathematical-historical items in the Museum, approximately chronological order. A number of items came from the Patent Office Museum and/or were preserved at the instigation of Bennett Woodcroft. As already noted, many of these are not on display at any given time.

Pieces of a Byzantine geared astrolabe, the second oldest example of computational gearing, the only representative of the passage of gearing from the Greeks to the Arabs. This was brought to the Museum by a caller in 1983 and thoroughly investigated and reconstructed by J.V. Field and Michael Wright, who have described it in an illustrated booklet.

A microscope made for Hooke by Christopher Cock, c1675. This is in Optics.

Watt's original experimental model steam engine with separate condenser of 1765, what is apparently his second model and the first experimental tubular surface condenser and his workshop. The models came from James Watt & Co. in 1876 and the workshop from J. M. Gibson Watt in 1924 - it has not been disturbed since Watt's death in 1819 and includes some of his three dimensional copying machines.

Boulton & Watt's rotative steam engines of 1788 and 1797. The mathematically and mechanically minded should look closely to see Watt's parallel motion-the first linkage, of which he was most proud - and the 'sun and planet' gearing, developed because someone had been allowed to patent the crank!

The prism used by William Herschel to discover infrared rays, c1800; Captain Henry Kater's brass yard and the notes describing the determination of its length.; early examples of molecular models, including those of Wollaston and those used by Daniell in the 1830s; Crookes' tube used to show that cathode rays could be deflected by a magnet; the vacuum tube used by J. J. Thomson in discovering the electron in 1897; an example of Ambrose Fleming's conversion of a light bulb into a diode; the Bragg's X-ray spectrometer of 1913, Aston's first mass spectrograph of 1919, part of Cockcroft & Walton's first accelerator used in 1932 to first disintegrate a lithium nucleus in 1932; the central part of Lawrence and Livingstone's (first?) cyclotron of 1932; an example of Pam, the first portable transistor radio in Britain, 1956; Fresnel lens from a Devon lighthouse.

I am most grateful to Jane Wess and her colleague Rod Smith for assistance in pinning down the present (Summer 2000) location of some items in this description. I remark again that the displays in a vast museum such as this are constantly being renewed, and some may be different if you are reading this in future months or years; if you are interested in an item here which you cannot find it is always worth asking the staff-often special arrangements can be made to see things not on public display.