Welcome to the Agricultural History of Downtown Santa Cruz tour.

I am not a historian; I don’t have the training. I don’t even think of myself as an amateur historian, because my knowledge is spotty and my understanding of local history resources is pretty incomplete. I started learning about local history as a way of giving shape and depth to the walks I take around town. I appreciate having a story, or rather a series of vignettes, that add dimension to location

It is possible that some of you know more about local history than I do. It is likely that several of you will know particular bits about the stuff I’m covering that I don’t know or don’t have time to cover. But my tours aren’t about completeness; they’re about bits and pieces.

So now I’ve told you that you’re taking a tour with a person who is not a historian, and who doesn’t claim or even strive for thorough knowledge. The final strangeness is that I’m giving a tour of things that don’t exist. I’m not going to be able to show you an orchard or a vegetable garden. I’m going to point to where they no longer are.

I would like to introduce the idea of the palimpsest. “Palimpsest” means “scraped again” and was used to describe Roman wax tablets, which were written on then scraped, then written on again. When people began to write things on cured animal hide (vellum), they still reused the material. The ink was removed by soaking the hide in milk and oat bran, then the hide was scraped and written on again. But over time, the underwriting starts to reemerge. This ghost of the past writing, seen foggily through the interference of the overwriting, is the magic of the palimpsest.

Let’s take for our example the Archimedes palimpsest. Originally written in 3rd century B.C.E. and transcribed in 900s C.E., this work was washed and written over in 1229, then bound into an Orthodox Christian book of prayers.

The manuscript—whose movements, whereabouts, and interactions are complex and international—had been further compromised by forgers who in the 1930s added four Byzantine-style illustrations, hoping to make it look older and increase its value to collectors. The illustrations completely obscured parts of the earlier text.

In the modern day, scholars and scientists used ultraviolet, visible, and infrared wavelengths to try and see the Archimedes text but the techniques were only partly successful. Then Stanford physicist Uwe Bergmann, working on the physics of photosynthesis and particularly photosynthesis in spinach, made a creative leap and reasoned that the method he used to track iron in spinach could be similarly applied to track the iron in old ink. He and his team used the Stanford Linear Accelerator to provide X-ray florescence which revealed the scraped over, written over, and painted over text.

And so I ask: what do we need to find the hidden past? History is always in some sense fragmentary, covered by new texts and by forgeries. Only a leap of imagination can help us see the underwriting on this palimpsest and allow us to reconstruct—as best we can—the original.

The writing is gone. Let’s go read it.