The Reckoning of Time - Mathematics and the Liberal Arts

The Reckoning of Time - Mathematics and the Liberal Arts

To refine search, see subtopics The Sundial, The Calendar, and The Clock. To expand search, see Time and Space. Laterally related topics: Astronomy, Cartography, Navigation, and Surveying.

The Mathematics and the Liberal Arts pages are intended to be a resource for student research projects and for teachers interested in using the history of mathematics in their courses. Many pages focus on ethnomathematics and in the connections between mathematics and other disciplines. The notes in these pages are intended as much to evoke ideas as to indicate what the books and articles are about. They are not intended as reviews. However, some items have been reviewed in Mathematical Reviews, published by The American Mathematical Society. When the mathematical review (MR) number and reviewer are known to the author of these pages, they are given as part of the bibliographic citation. Subscribing institutions can access the more recent MR reviews online through MathSciNet.


Ammarell, Gene. Sky calendars of the Indo-Malay archipelago. History of oriental astronomy (New Delhi, 1985), 241--247, Cambridge Univ. Press, Cambridge, 1987. SC: 01A13 (01A07), MR: 1 160 818.

The people of the Indo-Malay archipelago used astronomical events such as the heliacal risings or culminations of stars, the solstices, and the zenith sun to make calendars or otherwise determine the most favorable time for rice planting. There is sometimes a need to measure or mark angles in this context, and methods used include shadow methods (marking the lengths of the tangents on some sticks), an ingenious method of tilting a bamboo stick filled with water, and a method of noting when kernels of rice rolled off an open palm when raised to Orion at dusk. (In the case of one tribe, someone observed that "the time was right for planting when a man looked up to see the Pleiades and his fat fell off!") Closely related topics: Indo-Malay Archipelago, The Calendar, Astronomy, Angular Measure, Agriculture, The Kenyah, The Kayan, Java, The Dyak, The Maloh, and The Iban.

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Angell, Ian O. Megalithic mathematics, ancient almanacs or neolithic nonsense. Bull. Inst. Math. Appl. 14 (1978), no. 10, 253--258. (Reviewer: C. R. Fletcher.) SC: 01A10, MR: 80f:01002.

Discusses different explanations for the shapes of megalithic stone rings. The author briefly discusses some of the theories of Alexander Thom, which involve an astronomical calendar and an effort to make the circumference equal to 3 times the "diameter" rather than the irrational pi. He then discusses two new theories of his own. One explains the shapes of the stone rings as extensions of the ellipse, generated with three or four pegs and a string rather than with just the usual two. The other explains the shapes as an effort to store shadow lengths. Neither theory may be given entirely in earnest. A theme of the paper is how theories may start as intellectual games, go out of control, and be changed into pseudo-science. Closely related topics: The Stone Builders, Astronomy, The Calendar, The Ellipse, Pseudoscience, and Alexander Thom.

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Ascher, Marcia. Before the conquest. Math. Mag. 65 (1992), no. 4, 211--218. SC: 01A12, MR: 93g:01006.

Discusses the Inca and the Maya. With the Inca, focuses on the quipu. Most quipus were destroyed by the Spanish, who thought them to be the work of the Devil, but some 550 remain. Discusses their basic structure. A fascinating puzzle in the article is a pair of quipus which seem to represent data in a similar yet inexplicable way. With the Maya, focuses on their calendar. Again, much has been destroyed. For example, there only four codices remain, whereas thousands were burned by the Spanish. Fortunately, many stelae still exist. These show a calendar system with a variety of cycles. These cycles to us suggest Chinese Remainder problems. Examples of cycles are the 260 day ritual almanac composed of a cycle of 13 numbers and 20 named dieties, the vague year of 365 days composed of a cycle of 20 numbers within a cycle of 18 named dieties plus 5 unnamed days, their least common multiple (the calendar round of 18,980 days), the long count of days (in effect, multiples of 360 days plus a remainder), a 9 day cycle of Lords of the night associated with gods of the underworld, a lunar cycle of 29 and 30 day months, 13 levels in the heaven, a cycle of 4 cardinal directions (associated with different colors), sometimes used in conjunction with an 819 day cycle of the rain god. The Mayans appear to have had keen astronomical knowledge. The author notes that the error between real and tabulated times of the position of Venus would be off by just two hours in 500 years. Closely related topics: The Inca, The Quipu, The Maya, The Calendar, Astronomy, and Chinese Remainder Problems.

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Cordrey, William A. Ancient Mathematics and the Development of Primitive Culture. Mathematics Teacher 32 (1939), 51--60.

Discusses number words and systems of time reckoning for a wide variety of groups. Although many readers may be familiar with the Egyptian and Babylonian number systems, there are many interesting examples from the indigenous peoples of North and South America. The reader may want to ignore statements regarding the relative levels of different cultures. Reprinted in Swetz, Frank J., From Five Fingers to Infinity. Closely related topics: Number Systems, Number Words, and Indigenous American Mathematics.

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Court, Nathan Altshiller. Mathematics in the History of Civilization. The Mathematics Teacher 41 (1948), 104--11.

How different concerns of society influenced mathematics. How the development of the concept of number is reflected in language. How the concept of how many led to arithmetic. How the concept of how much led to geometry. (Taxation and agriculture also contributed to both.) Efforts to keep time led to trigonometry. Navigation and associated astronomical problems led to logarithms [and more trigonometry]. Problems in artillery led to graphs. Both required an understanding of motion. Analytic geometry and calculus were invented in part to better understand motion. Statistics developed to understand problems in the social sciences. Also discusses the nature of mathematics: mathematics for its own sake and the axiomatic method. Reprinted in Swetz, Frank J., From Five Fingers to Infinity. Closely related topics: Why Study History Of Math, Mathematics in Language, Number Systems, Arithmetic, Geometry, Taxation, Agriculture, Astronomy, Trigonometry, Artillery, Graphing, Navigation, Dynamics, Force, and Motion, Analytic Geometry, Calculus, Statistics, Social Science, and Proof.

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Dilke, O. A. W. Mathematics and measurement. Reading the Past, 2. University of California Press, Berkeley, CA; British Museum Publications, Ltd., London, 1987. 64 pp. ISBN: 0-520-06072-5. (Reviewer: Richard L. Francis.) SC: 01A05 (01A15 01A20), MR: 89f:01003.

This very interesting book discusses many aspects of mathematics in the Roman empire, Egypt, Babylonia, Greece, and sometimes other cultures. The book discusses systems of measurement of length, area, volume, and weight, mathematical or para-mathematical subjects such as surveying, cartography, interest rates, taxes, time keeping, games, and numerology. Also discusses number systems. Much of the discussion on number systems may be familiar, but here there is also a little that may be a little less familiar, such as the use of Etruscan letters in the early Roman numerals. In a work of this scope, the author of the book is not to be faulted that there may be some disagreement with occasional facts. The discussions on the mathematics of the Romans are particularly interesting; there are few other studies touching on Roman mathematical practices at all. Closely related topics: The Roman Empire, Ancient Egypt, Sumerians and Babylonians, Greece, The Measurement of Distance, The Measurement of Area and Volume, The Balance and the Measurement of Weight, Surveying, Cartography, Banking, Taxation, Games, Numerology, and Number Systems.

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Fields, Margaret. Practical Mathematics of Roman Times. Mathematics Teacher 26 (1933), 77--84.

Surveys Roman mathematics. Some of the most interesting examples come from the De Architectura of Vitruvius, which discusses principles of symmetry and proportion and how to use them in architecture. Vitruvius goes as far as how to correct for an optical illusion on the capitals of columns. He also discusses geometric procedures to be used in laying out a town (to shut out winds), and various Roman instruments, including leveling instruments and an instrument for measuring distance called a hodometer. The hodometer is used for "telling the number of miles while sitting on a carriage or sailing by sea", and is particularly ingenious. Second to Vitruvius, the most important source on Roman engineering may be the Urbis Romae of Frotinus, which includes mathematical rules (not entirely successful) to determine the flow of an aqueduct. Surviving Roman bridges show a high level of skill; there were surely mathematical principles behind their design, but no detailed study has survived. Roman tunnels are equally impressive. Heron discusses how to use an instrument called the "dioptra" to survey for tunnels, measure the width of a river, and so on. Roman sundials were relatively unsophisticated. Reprinted in Swetz, Frank J., From Five Fingers to Infinity. Closely related topics: Vitruvius, Architecture, Symmetry, Proportion and the Golden Ratio, Optics, Leveling, The Measurement of Distance, Frotinus, Heron, Surveying, and The Sundial.

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Gerdes, Paulus. On mathematics in the history of sub-Saharan Africa. Historia Math. 21 (1994), no. 3, 345--376. SC: 01A13, MR: 95f:01003.

This paper broadly surveys the recent research in sub-Saharan mathematics (and some related areas as well). Areas discussed include prehistoric mathematics (e.g., the Ishango and Border Cave bones), number systems and symbolism (including algorithms and education), games and puzzles (for example, a leopard-goat-cassava leaf river crossing problem and a "topological" puzzle), symmetry in African art, graphs or networks (e.g. Tschokwe sand drawings), architecture (one case involving magic squares; also a brief reference to fractals). Gerdes mentions string figures as a possibly productive future research area; he gives some starting points. He also discusses related areas, such as technology, and studies on language and mathematical concepts. A goal of the studies mentioned is apparently to better understand mathematics learning in Africa. Some studies focus on logic. Questions on interaction with ancient Egypt are still largely open. A better understanding of Islamic mathematics in sub-Saharan Africa is desirable as well. The author also touches on factors connected with the slave trade; e.g., the remarkable but not perhaps entirely atypical abilities of Thomas Fuller. Includes an extensive bibliography. Closely related topics: Sub-Saharan Africa, TallySystems, Games, Puzzles, Topology, Symmetry, Continuous Tracing Problems, Architecture, Magic Squares, Fractals in Art, String Figures, Ancient Egypt, Education, Mathematics in Language, Logic, The Islamic World, and Thomas Fuller (1710-1790).

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Kudlek, Manfred. Calendar systems. Mathematische Wissenschaften gestern und heute. 300 Jahre Mathematische Gesellschaft in Hamburg, Teil 2. Mitt. Math. Ges. Hamburg 12 (1991), no. 2, 395--428. (Reviewer: J. S. Joel.) SC: 01A99 (00A69), MR: 92j:01079.

A rare and unusually wide ranging look at calendar systems in a variety of cultures. Explains some of the astronomical issues involved. The author discusses calendars of Egypt, Babylonia, the Roman Empire, Greece (Athens), the Islamic World (especially Persia), India, China (only gives a taste, since more than 50 official calendars were used), Japan and Vietnam (their calendars were connected with China), Java, Bali, Guatamala (by the Cakchiquel Indians), revolutionary France, the Mayas, and in the Jewish tradition. Discusses the computation of the date of Easter. (The computation of Easter was of course one of the primary goals of mathematics instruction in the middle ages.) There is information on how to correlate these calendars as well (in terms of Julian dates). Closely related topics: The Calendar, Ancient Egypt, Sumerians and Babylonians, The Roman Empire, Greece, The Islamic World, India, China, Japan, Vietnam, Java, Bali, The Maya, Guatemala (and Cakchiquel Indians), France in the 1700s, The Jewish Tradition, and Religion.

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North, J. D. Astrolabes and the hour-line ritual. J. Hist. Arabic Sci. 5 (1981), no. 1-2, 113--114. SC: 01A99, MR: 84h:01102.

The author examined 132 astrolabes in the Museum of the History of Science in Oxford, and concluded that they were of less value than one might expect for timekeeping: "Our of 132 astrolabes examined, 41 instruments have the unequal-hour lines, and yet only four could have been used in at best a rough and ready way to find unaided the unequal hour." Equally interesting, the author observes that "not a single medieval instrument has survived in a form which would suggest that the unequal-hour lines were used meaningfully." All this is in spite of the fact that the author observed that "it seems to be commonly believed that a standard part of the engraving of the back of an astrolabe is a set of hour-lines forming, as it were, a double horary quadrant." Closely related topic: The Astrolabe and Related Instruments.

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Ollerenshaw, Kathleen. Some personal delights in geometry---from earliest days to fractals. Bull. Inst. Math. Appl. 27 (1991), no. 4, 65--75. SC: 01A99 (51-03 58-03), MR: 1 110 875.

Dame Kathleen Ollerenshaw discusses some of her favorite results and ideas of geometry. The examples range from Euclid to the present, and include illustrations of projective geometry, a fixed point principal (two superimposed identical maps on different scales will share a point in common), the nine-point circle (with proof), Pascal's mystic hexagram theorem and its generalization to general conics, and Briachon's theorem, obtained as the dual of Pascal's theorem. She briefly discusses the attempt to represent astronomy in geometrical terms, mentioning a frantic search for a "Clock in the Sky" for navigational purposes, achieved to some extent by observations of the moons of the planet Jupiter. She closes with some illustrations and a brief discussion of fractals. One of her examples is her own (apparently new) observation that if one has three circles intersecting in pairs, the three chords joining the points of intersection meet in a point; a proof is given in the article The Ollerenshaw point. Closely related topics: Geometry, Projective Geometry, Geometric Fixed Point Principles, Line-Point Duality, Astronomy, and Fractals.

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Proverbio, Edoardo. The contribution of the mechanical clock to the improvement of navigation. Longitude zero 1884--1984 (Greenwich, 1984). Vistas Astronom. 28 (1985), no. 1-2, 95--103. SC: 01A99, MR: 809 625.

It is a relatively simple matter to measure latitude with simple instruments; your latitude is for example nearly equal to the altitude of the pole star above your horizon. Longitude can in theory be determined by what amounts to determining your time zone; this can be determined by noting the time of sunrise. If you note that the sun rises three hours later than it did at home, you would expect to be about 3 time zones, or 45 degrees to the west of home. However, until the mid 1700s, there was no accurate way to keep track of time at sea; traditional methods such as water clocks were hopeless on a moving ship. A solution was proposed by the mathematician and astronomer Galileo, who discovered the moons of Jupiter. These moons occasionally eclipse each other, and if one could predict when that would happen, one would in effect have a clock in the sky. Other mathematical/astronomical methods were proposed as well; in theory if you have accurate enough predictions of the orbit of the moon, you can predict time by observations of the moon as well. Unfortunately, mathematical methods were not yet adequate to predict the positions of astronomical objects with enough accuracy, and the computations could have been difficult for the average sailor in any case. So attention began to focus again on finding a more accurate clock. Some of the problems in clock design involved mathematics as well. For example, it was known that a pendulum will swing in roughly equal time regardless of the size of the swing. (A famous story tells of how Galileo discovered this in church one day, by comparing with his pulse.) "Roughly equal" wasn't good enough, and a mathematically very interesting solution was suggested by the mathematician and scientist Christiaan Huygens. His suggestion involved improving the accuracy of the pendulum by using the tautochrone property of the cycloid. Huygens tried a number of other things as well. Of course, there is much more that doesn't involve mathematics so directly. A fascinating article. Closely related topics: Navigation, The Clock, Astronomy, Galileo Galilei, Christiaan Huygens, and The Cycloid.

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Wren, R. L. and Rossmann, Ruby. Mathematics Used by American Indians North of Mexico. School Science and Mathematics 33 (1933), 363--72.

Surveys the use of numbers and geometric shapes in various North American indigenous peoples. Includes sacred numbers, number words, including an unusual instance of subtractive number words in the Bellacoola of British Columbia, number systems, reckoning of time and seasons. Also includes geometric characteristics of dwellings and (briefly) textiles, basketry, pottery, and tattooing. Often pottery designs were borrowed from textile art. A common principle in weaving is that no line, curved or otherwise could intersect itself. (Is this principle partly responsible for the popularity of spirals?) Reprinted in Swetz, Frank J., From Five Fingers to Infinity. Closely related topics: Indigenous Mathematics of North America, Numerology, Number Words, The Bellacoola, Pattern, Weaving, Basket Making, Pottery, and Tattoos.

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Zaslavsky, Claudia. Africa counts. Number and pattern in African culture. Prindle, Weber & Schmidt, Inc., Boston, Mass., 1973. x+328 pp. SC: 01A10, MR: 58 #20993.

This book is an excellent introduction to the mathematics of (primarily sub-Saharan) Africa. The best tribute to its importance may be in Gerdes, Paulus, On mathematics in the history of sub-Saharan Africa. Gerdes writes "In her classical study Africa Counts: Number and Pattern in African Culture ..., Claudia Zaslavsky presented an overview of the available literature on mathematics in the history of sub-Saharan Africa. She discussed written, spoken, and gesture counting, number symbolism, concepts of time, numbers and money, weights and measures, record-keeping (sticks and strings), mathematical games, magic squares, graphs, and geometric forms, while Donald Crowe contributed a chapter on geometric symmetries in African art." Regarding geometric symmetries, it is primarily the frieze patterns and plane patterns that are discussed; there is surely more work to be done on the bichromatic frieze and plane patterns. Many readers will wish to explore further. Gerdes' paper should be invaluable for this, not least for its extensive bibliography. Another useful resource is the newsletter distributed by the African Mathematical Union's Commission on the History of Mathematics in Africa (AMUCHMA). Closely related topics: Sub-Saharan Africa, TallySystems, Finger Numerals, Counting, Numerology, Money, Measurement, Games, Continuous Tracing Problems, Architecture, Magic Squares, Mathematics in Language, Frieze Patterns, Plane Patterns, The Islamic World, and Anthropology, General.

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