In the First Observation in his great book Micrographia (1668), Robert Hooke describes looking through his microscope at a needle. What to the eye seemed smooth and sharp was revealed to be ‘a crude affair’, pock-marked and blunt. By contrast, he noted, whenever he
looked at the works of nature, no matter how deep
he went, ‘greater excellencies’ were revealed.
This thought came to mind when, after looking at
assorted fleas, fruit flies and other staples of school
biology through my microscope, I wondered what,
if anything, the edge – rather than the transparent
body – of the slide might reveal. I was astonished.
My first thought was of a tsunami breaking across a
narrow shoreline, and I surmised that the repeating
curved lines must be generated by conchoidal fractures
– named after the similar features of a mussel shell –
induced when the slide was cut. I set about inducing
tiny fractures by rolling the shaft of a screwdriver along
the corner of some blank slides. Viewed obliquely, these
more violent assaults yielded much calmer ‘marine’
images, the iron oxide-induced green of the glass acting
as a convincing sea against a narrow shore above which
towered ‘conchoidal’ cliffs.
Excited by these first results I consulted my friend
Rodney Bender of IGP (Innovative Glass Products) to
see if he could suggest other ways of distressing glass.
We had previously collaborated on a display cabinet
whose glass front made use of glue-plucked glass. He
also suggested knapping the surface with deer antler. It
sounded improbable, but he assured me the technique
went back to the Neolithic, when it was used on a natural
form of glass, the volcanic rock obsidian – which, one
might note, is still preferred by some surgeons to metal
scalpel blades for especially delicate operations. Viewed
with an electron microscope, obsidian is impossibly
smooth while the stainless steel blade might as well be ‘a
brick covered in sandpaper’, to quote one surgeon.
Archaeologists refer to deer antler as a ‘soft hammer’,
with the right combination of firmness and slight
sponginess. And antler-knapping glass yielded
wonderful results – still sea and cliff-like, but leaving
any pretence at real landscapes behind.
Although a physical process, glue-plucking feels close
to alchemy. Google is silent on the technique, which
is thought to date back to the early 19th century and
typically involves sandblasting the glass and then
covering it with a glue derived from the innards of
animals, rich in collagen-based connective tissues
(the same kind of glue, incidentally, is used in violin
manufacture). The surface is allowed to go ‘leather
hard’, typically taking a few days. The glass is then
heated, forcing the collagen to contract until the