Monday, January 24, 2005

Writing instruments

It's a poor craftsman that blames their tools... or so the adage goes. While it may be bad form to blame tools for errors, it's undeniable that craftsmen use tools. Indeed, the use of tools is one of the characteristic features of not just craftsmen but of all homo faber. As such an important input to our productive processes, tools deserve special attention.

I have recently been considering the evolution of technical drawing and illustration. I have a particular fascination with the theatrum machinarum of the sixteenth and seventeenth centuries. During this period we see the Middle Ages give way to the Renaissance and the emergence of whole new genres of societal features; the technological world driven by the guilds and oral culture of traditional artisan society gave way to first, written documents, and second, printed documents.

This process certainly wasn't linear since new social and technological forces had a performative effect; for example, new technologies in armaments led to the pre-industrial mass production of guns and cannon. These proto-factories essentially re-instituted oral culture and craft tradition in a field where knowledge had begun to be disseminated by the notebooks and portfolios of itinerant “master gunners”.

One of the greatest technologies to emerge was the printing press. During this period, the engineer working alone at his drawings and notebooks began to be challenged by the engineer who worked with artists and engravers to publish books that were collected by royalty and community leaders.

While both notebooks and printed books were important, the creative work at some point had to be executed in the old fashioned manner with pencil and paper. The purpose of this short piece is to explore the history of the drawing tools used by engineers.

Perhaps the most basic cognitive tool of the engineer is a marking. A marking requires two things: something to make the mark and something to carry the mark. We'll start with the carrier.

It's difficult to know where to begin a history of things that are marked. Do we start with the cave walls of Lascaux? Or do we discuss the earlies types of paper such as leaves? At the risk of displaying a strong western bias, I will begin this investigation with manufactured things that are marked (artifacts) rather than natural things that are marked (biofacts).

The earliest materials for carrying marks were the clay tables of the Summerians (~3500 BCE) and animal skins. The first evidence of a manufactured writing material is papyrus from 2400 BCE. Papyrus eventually makes its way into our western history, appearing among the Greeks by 650 BCE. The Greeks—and later, the Romans—also used wax tablets to record notes. These tablets generally consisted of a wooden frame supporting a wax writing surface and were called pugillares by the Romans. Several pugillares bound together with string formed a codex. Between 197 BCE and 159 BCE a herd of cattle is raised near Pergamum specifically for the purpose of providing skins for writing on. These specially prepared skins became known as “parchment”. The first paper making occurred in China around 150 BCE using hemp fibers suspended in water. Between 100 BCE and 100 CE the papyrus scroll largely disappeared in the Roman world being replaced by the codex. In 105 AD Ts'ai Lun becomes the official discoverer of paper in China. Following the collapse of the Roman empire and the rise of Islam, the supply of papyrus from the middle east to Christendom was cut-off, perhaps instigating the dark ages. By 750 CE paper making had reached Samarkand. The first paper mill in Europe appeared in Moorish Spain in 1151. Paper mills were established in Christendom—especially Italy—late in the 13th century.

During the time I'm most interested in, paper gradually began to replace parchment; however, both materials were quite expensive. Writing materially gradually became cheaper as printing led to the development of the paper industry. Some commentators have even credited the spread of the Black Death following the introduction of the printing press led to a steady supply of rags—an essential ingredient of paper at the time—thereby lowering the costs of writing materials in general.

While parchment and paper quite readily take marks, a tool for making those marks is required. The quintessential image of technology is the engineer sitting behind a drawing board with a pencil in hand and drawing instruments at the ready. This image is most certainly not applicable to the early engineers. While the drawing compass was known in antiquity, both the pencil and drawing tools emerged later.

The earliest writing instruments were pigments applied to various surfaces. While fingers may have worked for the illustrators of Lascaux, the brush proved to be a far more effective writing tool. Our modern pencil is a direct descendant of the brush. The pencil gets its name from the penicillum, or pencil brush, of the Romans. A pencillum was simply a narrow sort of brush (penicullus) used for applying pigment to a surface. The use of the pencil brush has been used throughout the ages—Leonard da Vinci used a pencillum in addition to a quill pen to illustrate his manuscripts.

For making marks on wax tablets (pugillares) the Greeks and Romans used a very different tool: the stylus. The stylus was simply a narrow pointed rod of metal or bone that an individual could use to scribe marks in a wax tablet. A stylus typically had one pointed end for making marks and a flat end that could be used to erase marks by smoothing out the wax. The stylus of ancient Rome also had a purpose beyond simply making marks on a wax tablet. Caesar, for example, apparently found having a sharp metal object at hand very useful when he stabbed Cassius in senate. Similarly, Caligula incited the “massacre by styles” of a senator.

[I'm somehow reminded of the year I spent doing development work in Central America. I lived in a very small and rural community where most of the men worked in the surrounding sugar cane fields. They all carried machetes honed to a razor's edge. Through hours of long use these men wielded their machetes like extensions of their own arms. During the weekends, it was not uncommon for two drunk men to begin fighting and they would fight with whatever was at hand, typically their machetes. To watch their thrust and parry was really quite remarkable. The events would not have been out of place in a Restoration play about two young rakes dueling to protect their honour. I suppose that the Romans, in a very similar manner, fought with whatever they had at hand: the stylus. The machete, however, is so very unlike a stylus. The machete can be used in the field; it is a tool of both violence and utility. It also affords both attach and defense. The stylus, with but a single sharp point, can only be used for attack, preferably when the defendant is unaware. Perhaps the ancient stylus is less removed from the modern pen than we may think!]

The stylus had uses other than just making marks on wax. Metal styluses, or metalpoints, could be used to make faint marks on paper. Lead was particularly effective for making marks. Primitive pencils of lead shaped like styluses were called plummets and were particularly effective for making margin lines and guide lines for writing upon with ink. Stylus points, however, are relatively weak so the ancients began to use lead disks with a sharp edge to scribe faint marks on a page. The Greeks called such an item a paragraphos while the Romans referred to it as a productal or simply a plumbum. The plumbum remained alongside pencils and goose quill pens until the early nineteenth century.

The use of the penicillum and the stylus persisted due to their utility. For example, it has been suggested that Chaucer actually wrote the Canterbury Tales on wax tablets with a stylus before transferring his final revisions to a more permanent format, likely parchment. However, it is unlikely that Chaucer would have used a penicillum to ink his masterpiece: the reed pen was in use by the second century and quill pens by the seventh century.

During the Renaissance, scholars and artists typically worked with either the quill pen or the pencillum. Some artists and engineers—Leonardo included—would either scribe their pages with a fine blade or use a metalpoint to sketch their drawings prior to inking. The use of metalpoint was a rather tedious process since the pages to be written upon had to be prepared by applying a wash of finely ground pummice is a solution of glue and flour paste. The metalpoints themselves were likely made of lead alloyed with other metals. The German monk Theophillus, for example, wrote in the twelfth century of metalpoints made from an alloy of lead and tin to lay down a design on wood.

The next big evolution in writing instruments was the appearance of plumbago, graphite suitable for use in writing. The first natural source of plumbago was discovered in the Cumberland Hills of Britain. While the date of the actual invention of the pencil remains uncertain, Konrad Gesner both described a pencil and provided an illustration of one in 1565. The use of pencils quickly spread throughout Christendom despite the intermittent supply from Barrowdale in Cumberland.

War broke out between France and Britain in 1793. The pencil had become such an important tool that France was desperate to locate a replacement or manufacture a synthetic. The Minister of War, Lazare Carnot, commissioned Nicolas-Jacques Conté to create an alternative (Conté was an associate of Gaspard Monge, another important figure in the history of technical drawing). By 1794 Conté had discovered a way of mixing powdered graphite potter's clay and firing it at high temperature. This process was soon adopted throughout the world and remains the basic approach for manufacturing pencil leads.

Conté pencils had a great advantage over their Barrowdale brethren. Through changes in the formula, pencil leads of various darknesses could be produced. By the mid nineteenth century the use of various line weights had been incorporated into common drawing practice. At the time, it was common for draftsmen to construct the drawing with pencil and then ink the drawing when all of the pencil work has been completed. Pencil and pen was generally used in conjunction with coloured washes, a practice that predated the Conté process.

The use of pen and pencil in drawings was challenged by a number of technological advances. The first mechanical pencils, for example, were introduced by A.W. Faber in 1873. According to Petroski, they never really caught on [that said, when I was taught technical drawing in 1992 we used mechanical pencils... although I did have one woodcased 4H that I preferred for construction lines!] Blueprinting, emerging in the 1870s led to the elimination of coloured washes in drawings by 1914. The need for quick production and the use of improved papers and pencils eventually led to the elimination of ink finishing by about 1925.

The pencil's primacy in engineering design remains unchallenged. While CAD systems are now quite common, the practices of rough and preliminary design, and drawing revisions all typically get done with a pencil.

Other drawing tools have a similarly deep history. The Egyptians, for example, used looped string to draw circles while the Romans used bronze compasses and bone or ivory rulers. Compasses, dividers, and rulers remained the primary layout tools for a number of centuries. Ship draughts from the sixteenth century provide clear direction on how and where to locate compass centres for laying out the complex curves of hull ribs.

The modern apparatus of engineering—the t-square, triangles, etc.--are relative new comers. While squares were have been used for aeons in construction, the use of the t-square in technical drawing was not described until Farish's work of the 1820s. He also describes the importance of proper drawing board. Thomas Bradley's book of 1836, Practical Geometry, describes the extant drawing technology: compasses, dividers, hair dividers, triangle compasses, beam compasses, proportional compasses, squared boards, t-square, t-square with movable blades, parallel rules, lines of chords, protractors, pentographs, centrolineads, and illiptographs. Missing from this list is the triangular set square. However, set squares became quite popular after about 1860 likely due to the rise in popularity (perhaps only pedagogical popularity) of Farish's work on isometric drawing.

All information drawn from Booker's “A history of engineering drawing” and Petroski's “The pencil : A history of design and circumstance”


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