Introduction: The Original IPad: Diptych
Ancient people had pretty interesting ways of recording their thoughts, or keeping track of business accounts. Clay tablets were pretty good, but were permanent and hard to store. Papyrus and vellum were great alternatives for permanent records but often rotted. The diptych (two panel), or triptych (three panel) was a recessed board with wax panels that could be inscribed and erased as needed. This project was first completed as part of a "Technology of the Ancient World" course in the Classics department at UMass Amherst.
Step 1: The Archaeology
The re-creation of the tablet was based on archaeological evidence culled from many different sources both Greek and Roman. There are two rather famous wall paintings from Pompeii, one depicting a lone woman holding a set of ceraculae (that's the Latin word for the diptych), the other painting showing Paquius Proculus and his wife, he holding a rolled scroll, she holding a ceracula. Another source was from three Greek red figure vases which date to around 500-480 b.c. that each show a man writing on some sort of hinged tablet with a two sided stylus. The final sources were actual artifacts recovered from various archaeological sites: Vindolanda by Hadrian’s Wall in England, a tablet recovered from a German site on display in the museum in Cologne, and a description of the tablet found in the Uluburun shipwreck off of the coast of Turkey. Each example varied in size however reinforced an average single tablet dimension around 25cm by 15cm. Similarly each ancient example that displayed the wax showed a black writing surface –a point that was initially overlooked in my reproduction.
Step 2: Harvesting
The process of extracting usable lumber from a log begins with splitting.The tools needed are very simple: a small hatchet used to make wooden wedges, a large sledge, and a saw or axe. During a particularly windy storm, the top half of a white pine tree came smashing down in my back yard. The tree it fell from was not the healthiest one on the lot due to a previous split a few years prior, so when the top fell it had already been attacked by bugs and there was a huge sap ball from where the tree was trying to heal. The log was split down the middle by sequentially driving wedges down the axis of the log and repeatedly striking them with the sledge. When the log was split in two I could then examine the interior grain of the log and select the best possible (least worm ridden) area to use. This selection was then sawn from the rest of the log and split once more, this time vertically to remove the outer rounded side and create a plank roughly parallel on two sides.
Step 3: Hewing and Truing
The next step was definitely the hardest for me.
This plank was then taken to the work bench where it was further shaped and smoothed out with the hatchet. This process proved to be dangerous due to the blade angle of the hatchet. Historically this hewing would have been done with an adze or a broad axe –two tools that are honed on one side only, the other side remains flat. Because the hatchet is sharpened on both sides like a “V” it is more useful as a cutting or splitting tool. When used to hew it tended to bounce away from the smoothing plane of the plank and often back toward my hand.
When the plank was hewn I was then able to take a plane and smooth it down perfectly flat; first by “scrubbing” across the grain to remove the big imperfections and then “running” with the grain to plane it smooth and flat. The same was done to the other side to bring it perfectly parallel with the first side. To ensure it was square and parallel I used a carpenter’s square- a tool directly from antiquity that remains unchanged to this day.
Step 4: The Problem With Unseasoned Wood.
I noted while using the plane that the wood was still a tad green and so put the boards aside for a few days to dry before I continued with any more steps. When I returned I found that the boards had warped slightly. Warping is caused by the uneven expansion or contraction along the grain lines following the tree ring pattern. The outer larger diameter rings have more freedom of movement than the smaller inner diameter rings and they are inclined to use that liberty. Unfortunately there is no good solution to counter the warp other than to re-plane the work. Due to this rework I removed approximately 1/8 of an inch to resurface and regain the parallel.
Step 5: Carving
Having planed, sized and squared both boards the next step was to carve out a recess to receive the wax writing surface. This was mostly done with a gouging chisel, a tool with a “C” cross section designed to remove a large amount of wood. The smoothing of the recess was done with flat carving chisels for the bottom plane and side with-grain walls and carpenters’ chisels for the end grain recess walls. This carving process surprisingly proved to be very different for the two boards; one board carved very easily, but was more difficult to vertically cut the end grains, the other board was harder to cut and attempted to grab the gouge and run it past my markings.
Next, I drilled two holes for the hinge string. The ancients apparently favored a type of drill bit that was flattish and had a centering spade. These drill bits are still found today and are often used for making larger holes than spiral bits can accommodate. I attempted to use this drill bit with a makeshift bow drill on a bit of scrap wood, but was so terribly unsuccessful that in order to not ruin the diptych I decided to cheat and use a spoon drill bit and a brace drill. The spoon bit is also historically accurate to the Roman times, however the brace drill is dated to the 14th or 15th century a.d.
Step 6: Wax On, Wax Off, Wax on Again
The final steps were to seal the wood with linseed oil, wax the interior recess and bind the tablets together. The wax was melted in a double boiler used specificially for candle making so that I wouldn't ruin any good cook ware. When it was fuly melted I carefully poured the wax into the tablets.
After coating the recesses with beeswax it was noted that any marks created on the yellowish-green wax were difficult to see in addition to the wax being somewhat transparent and being able to see a knot in the wood through it. The wax also proved very difficult to remove any writing markings by either scraping or smoothing. Upon re-inspection of the historical artifacts, it was then that the blackness of the wax was noted. Culling through internet sites suggested that the blackness was due to lampblack (soot), and furthermore adding the lampblack inclusions changes the consistency of the wax slightly and makes it easier to warm and erase. This being noted I removed and re-melted the wax this time adding a pinch of soot scraped from my wood stove, which ultimately fixed both the legibility and the hardness of the wax
Step 7: Done!
The diptych is interesting by itself as an artifact of wood technology; however, it is also a literary artifact. The presence of the tablets assumes a level of literacy in the owner of the tablets. It would be interesting to examine what, if any, messages survive on the tablets; or to see what kind of distribution these diptych had. The nature of the wax lends itself to the reuse of the tablets in a way that papyrus, vellum and even clay couldn't compare. Additionally a simple tablet like the one I created is easy and cheap to produce and can be mass produced by a craftsman in relatively little time.