« AntAnt: a tool for creating ant builds | Main | Concurrency in Software »

The Draw Boy

"There ought to be some mechanical way of doing this job, something on the principle of the Jacquard loom, whereby holes in a card regulate the pattern to be woven." -Dr. John Shaw Billings, on manipulating census data

The Jacquard loom , invented by Joseph Marie Jacquard was the world's first programmable machine, or as we call them today, computers. Jacquard's loom strongly influenced Charles Babbage who is typically credited with the first computer, and it is very likely that Herman Hollerith, inventor of the census tabulating machine (which used punch cards), was influenced by the loom. Jacquard himself was commissioned by Napoleon, who felt the creation of complex silk patterns could do with automation to benefit the industry as a whole. Complex patterns were preferred by the upper classes and royalty, in part because they were beautiful but also because they were absurdly time-consuming and expensive to make. Silk in particular represented a problem because it was so fine compared to cloth. Up to then complex silk weaving was untouched by the technical advances in the creation of regular linear and checked patterns on silk cloth. It was felt that non-linear patterns were not subject to productivity increases.

Duff's Draw Boy and Mr. Austin's Engine Loom

Jacquard felt differently. Jacquard was originally a draw boy. Silk weaving prior to Jacquard was done on draw looms, large devices operated by two workers, the weaver and the draw boy. The weaver handled the threading of warp threads, which are support threads, through weft threads, whcih are passed between the warp threads to form the cloth, so that the worven rows were laid out to form the desired pattern. The draw boy raised or lowered the warps' reeds, according to the weaver's instructions. The weaver made his threading decision on the pass of the shuttle as each row of the cloth was created. The reeds carried and guided the warp thread so that the weft the combination of reeds dictated where the alternate silk colour of the weft would appear on each back and forth pass of the shuttle as controlled by the weaver - over time a pattern would appear, as the weaver called out to the draw boy which reeds to lift on each pass. A master weaver and with a good draw boy might produce two rows per minute, or 2 square inches of patterned silk cloth a day. They really were boys, adults were too big to do this job. That's because the draw boy stood on top of the loom while lifting the reeds in accordance with the instructions of the weaver. Draw boys worked 6-8 hours a day in horrendous working conditions, lifting 30 pounds of reeds at a time on every call, were often ill and sometimes crippled by the work. Jacquard hated being a draw boy and had made the automation of the looms his life's work.

Jacquard loom

In an age of complex and increasingly powerful geared mechanisms powered by men or water, Jacquard's loom was ingeniously simple, not much more a plain set of rods and connectors that did not require much physical power to operate. The reeds were replaced by vertical steel rods, called hooks, as they had a hook on the top end. On each weave the rods could move either up or down as determined by the hook. The hook raises or lowers a harness which carries and guides the warp thread, now tied to a weight instead of a boys hands so that the weft laid above or below the warp, allowing a row of the pattern to be created as with the traditional loom. To control which rods were raised, pins on the side of could be pushed in, one pin for each rod, raising the rod and would spring back out when released. The pins were pushed in accordance to holes in a card, called the pattern card. The pattern card rotated on each pass of the shuttle, pushing in a combination of pins in accordance with the pattern.

jacquard pattern

To program a loom to create a pattern as you wove, you needed the pattern card called the Jacquard card. The blank card was overlaird with a pattern and a row of holes were punched into it as the blank card rotated. Once you had the card you could copy it as many times as you liked and run it on as many looms as you wanted - today we call that parallel computing. This allowed a weaver to weave up to 33 feet a day of a complex pattern instead of the time of pre-Napoleonic royal court, two square inches. The overall design allowed the weavers natural back and forth motion of the shuttle to determine the pattern, and removed the need for the draw boy.

It was a binary machine, whose physical operating technique, the use of pattern cards to dictate the arrangement on ones and zeroes that instructed the computer what to do next, was common in the computing industry well into the 1970s. The Jacquard loom itself is in common use, art and textiles students still train today on such looms.

woven Jacquard pattern


The Jacquard loom stayed untouched for almost 150 years. The power loom, invented by Cartwright some time before the Jacquard loom, but the advancement there was the use of electrical power supply rather than mechanism. The next advance in programming a loom occurred at the end 20th was get rid of the cards and program them using a much smaller representation of the pattern, as software. The modern digital computer, based in no small part on Jacquard's pattern matching technology, had eaten its parent. Today's Jacquard looms are computer controlled and electrically powered and can have hundreds or even thousands of hooks, but their technical architecture and functioning is essentially unchanged since 1801. The Rapier loom was the next technical (hardware advance), in having no shuttle to move back and forth its weaving mechanism today allows the weft to cross the warp 625 times per minute, speeds that cannot be matched by a weaver and which can create up to 120 metres of cloth per hour in a modern factory.

Hollerith's patent on the Key Punch

The extreme automation and productivity of the Jacquard and then Rapier looms clearly does not require a weaver as the job was understood by Jacquard. What you did need was someone to invent a pattern that could be transcribed onto a pattern card. This gave way to the designer, whose job it was to create patterns that would be inscribed on a card and later into a computer. Designers of all kinds are very much a by-product of industrial production. Because the volume of cloth produced was large, prices came down as more and more people could have access to fine silk. To drive demand, patterns were regularly altered to allow people to buy the newest and latest styles (silk finery having always been bought for coquettish reasons). In seasonal form, this constant alteration combined with cheap production and advertising of the new styles has more or less given rise to the fashion industry.

And what of the draw boys, and the job which Jacquard so despised when he was a boy? Despite the health hazards of their work, the looms were smashed by draw boys, who rioted, and who also threatened Jacquard's life.


January 5, 2006 02:53 PM