On the Prehistory of Programmable Machines: Musical Automata, Looms

Mechanism and Machine Theory 36 :2001) 589±603 www.elsevier.com/locate/mechmt On the prehistory of programmable machines: musical automata, looms, calculators Teun Koetsier Division of Mathematics and Computer Science, Faculty of Science, Vrije Universiteit, De Boelelaan 1081, 1081HV-NL Amsterdam, Netherlands Received 22 June 1999; received in revised form 20 October 2000; accepted 23 December 2000 Abstract An important characteristic of modern automation is the programmability of the machinery involved. Concentrating on the aspect of programmability, in this paper an attempt is made to study the following three kinds of machines in their pre-twentieth century development: computers, weaving looms and music automata. Ó 2001 Elsevier Science Ltd. All rights reserved. Zusammenfassung Zusammenfassung: Die Programmierbarkeit von Maschinen ist ein wesentlicher Zug der modernen Automatisierung. In diesem historischen Aufsatz wird die Entwicklung von drei Typen von program- mierbaren Maschinen ± Rechner, Musikautomaten und Webestuhle ± kurz im Zusammenhang skizziert. Der Autor beschrankt sich auf die Zeit vor dem zwanzigsten Jahrhundert und auf die Wechselwirkungen, die es zwischen der Entwicklung dieser drei Automatentypen gibt. Ó 2001 Elsevier Science Ltd. All rights reserved. Keywords: History; Automation; Programmable machine; Loom; Music automaton 1. Introduction In this paper, I will consider pre-twentieth century programmable mechanical devices and I will try to answer the question: ``What were the earliest programmable machines and what was their development?'' I will use the following de®nitions: `Àn automaton (Greek, `self-mover') is a mechanical device which (after releasing a brake) executes a function on its own and in a completely E-mail address: [email protected] :T. Koetsier). 0094-114X/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII: S0094-114X:01)00005-2 590 T. Koetsier / Mechanism and Machine Theory 36 (2001) 589±603 determined way'' [19, p. 131]. Moreover, `À programmable machine is an automaton that can execute (signi®cantly) dierent functions depending on the information stored on one or more material information carriers, that are part of the automaton''. A restriction to pre-twentieth century developments makes life conceptually easy. For example, we do not have to answer the question in what sense devices like software robots or agents are automata. 2. Heron's automatic theatre The Greek inventor Daedalus is the prototype of a mechanical genius. He is well known because of the wings that he allegedly designed for his son Icarus. It is, however, also reported that he built moving statues. The wings as a working design, undoubtedly, belong to the realm of ®ction, but it is said that he used mercury to change the centre of gravity of a statue and make it move, which does not sound impossible. There are also reports of the existence in Antiquity of heads that spoke. Also in the Indian and Chinese cultures there are stories about mechanical men or animals moving autonomously. Undoubtedly the stories are a mixture of fact and ®ction. Central elements in antique mechanical engineering are winches, toothed wheels :with triangular teeth), levers, pulleys, wedges and screws. Drachman's description of the mechanical theatre of Heron of Alexandria :1st century A.D.) gives a good idea of what could actually be done in Antiquity: The moving force is a heavy weight ®tting into a container full of millet or mustard seeds; the seeds run through a narrow hole, the weight comes down at a determined rate, and it turns an axle from which it is suspended by a cord. All the movements are taken from this axle by means of strings. A puppet or any other thing is turned by a string going round a drum; if it has to turn back, the string is passed over a peg in the drum and wound the other way. [...] If a thing has to happen only once, as a backcloth being dropped, it may be worked by a separate weight which is released by a string pulling out a pin. [...] A move- ment of the arm of a puppet, e.g., hammering, is produced by pins on a wheel acting on the short end of the lever [7, p. 197]. 3. The Banu Musa's automatic ¯ute player Heron's automatic theatre was an automaton, but it was not, in my sense of the word, programmable. The earliest known design of a programmable machine is the automatic ¯ute player that was described in the 9th century by the brothers Musa in Baghdad, at the time a major centre of knowledge. The Banu Musa's work was in¯uenced by their Hellenistic predecessors, but it contains notable advances on the Greek work. They ingeniously used small variations in air and water pressure and they used conical valves as automatic regulators [13, p. 60]. The basic idea described in The Instrument that Plays by Itself is that pins on a rotating drum open via little levers one or more of the nine holes of a ¯ute, which is positioned parallel to the drum. The wind for the ¯ute is generated by water that ®lls a reservoir and forces the air to escape. The drum is driven by a water wheel [8, pp. 88±118] :see Fig. 1). Strandh [20, p. 176] states that the Arabs could easily have invented the mechanical clock, had not the Mongols attacked the eastern parts of the Arabic empire. Baghdad fell in 1258. However, T. Koetsier / Mechanism and Machine Theory 36 (2001) 589±603 591 Fig. 1. The Banu Musa automatic hydraulic ¯ute player :Reconstructed by Farmer [8, p. 101]). the raids of barbaric tribes were only one of several factors that brought about the decline of Islamic science. According to Al-Hassan and Hill [13] religious fundamentalism, following eco- nomic and political erosion, was another factor. The more liberal early Islam had been the driving force behind the Arabic interest in science and technology. 4. Clocks and carillons During the early Renaissance developments accelerated. We ®nd the earliest description of an, in principle, programmable music automaton in a manuscript from Catalonia in Spain, dating from about 1300. It is a carillon of bells on top of a waterclock :clepsydra). The drawing is not very clear. It shows a carillon consisting of ®ve bells and a wheel carrying ball-headed pins :Fig. 2). There is also music for the carillon in the manuscript, from which it follows that the number of bells must have been ten [10]. Presumably the carillon started playing after the water clock released a crank. The drawing in Fig. 2 is intriguing. It is not clear how the carillon could have played the accompanying music with only one wheel. The wheel in the drawing may represent a cylinder. It must have been one of the last water clocks that was made in the West, because clocks using weights and a mechanical escapement were at that time introduced everywhere. Those ®rst mechanical clocks left a great impression on the people. The Strasbourg clock, for example, with its wrought iron cock that moved, became very famous. It was built in 1354. `Àt noon the cock opened its beak, stretched out its tongue, ¯apped its wings, spread out its feathers, and crowed, the crowing being produced by bellows and a reed'' [6, p. 81]. For many 17th and 18th century 592 T. Koetsier / Mechanism and Machine Theory 36 (2001) 589±603 Fig. 2. Catalonian carillon, ca 1300 [10]. philosophers the ®rst mechanical clocks also made clear how God's creation could be understood; it should be seen as an immense clockwork. The ®rst automatic carillons were small and used in monasteries and churches. Still in the fourteenth century the mechanical clocks on the towers were at most connected with a few small bells that rang when pins on wheels hit levers. These simple carillons were in principle programmable. Lehr gives the example of the Dutch town of Oudenaarde, that acquired in 1504 new wheels that played ``Veni Sancte Spiritus'' on the whole hours and ``Peccatores'' on the half hours [16, pp. 89±90]. Apparently the entire wheels had to be replaced to get another tune. Soon, however, about 1530, the cylinder with removable pins was introduced in the automatic tower carillon. At that time such carillons possessed two octaves. In the 17th and 18th centuries the automatic carillon was in particular popular in The Netherlands, Belgium and Northern France. In the automatic carillon of Bruges in Flanders even 120keys could be played [12, p. 62]. Parallel to the development of carillons, from the 15th century programmed music was often incorporated in astronomical clocks in churches and palaces. In the 16th century also chamber musical instruments with a program on a drum became rather popular. The early automatic mechanical and hydraulic organs also date from that period. For details I refer to [12]. 5. The ®rst programmable looms Although much more could be said about the further development of music automata in the 17th and 18th century, I will now turn to the history of weaving, basing myself largely on Van Gorp's work [11]. A loom must provide for ``shedding'': raising and lowering the ``warp'' threads so as to form a space through which the ``weft'' may be passed. The warp threads are raised and lowered by means of ``healds''. In a ``handloom'' healds usually consist of a number of strings, which are secured above and below to wooden ``shafts''. Each string is knotted near the middle to form a small eye. Large ®gured eects were produced in ``drawlooms'', where the warp threads T. Koetsier / Mechanism and Machine Theory 36 (2001) 589±603 593 were separately controlled by strings so that each assortment could be lifted separately.

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