Plaster of Paris

What pleasures he finds these days
are in simple things: like sorting weights,
balancing out measures.

To sprinkle a little more powder,
or bring, with slow drips,
a meniscus up to a line.

Mixing is easy. A fool could do it...
And so he mixes, then pours
the plaster into the mould.

Surprising how liquid it is.
He touches the brimming skin of it.
It seems... warm. Body temperature.

He can’t help laughing. It’s like
he had excited it
with that dose of tap water.

What do they say about water and life?
No life without water? Is that it?
Or no water without life?

He dips a finger in
and the wet plaster welcomes it.
When he draws it out: a white shroud.

Surprising how quick it sets.
On his hands, splashed drops on his face.
Quick, he thinks, scrape off the excess.

In half-an-hour it sets solid.
Half-an-hour of stillness, doing nothing.
Staring unfocussed at the garden.

He turns out the mould,
touches the cheeks smooth as silk,
the closed lids of the eyes.

It's a shock, the bright, mortuary hardness
that seems able to draw
the heat from his fingertips.

Where did the water go
that he poured onto white powder?
Where did that warmth go?

Why, now,
in this faithful likeness,
once more that stealing coolness?


+++++


Some Notes:

Plaster of Paris is made from gypsum, a form of calcium sulphate. Gypsum is a sedimentary rock produced by the evaporation of sea water trapped in lagoons. According to the nature of its impurities, gypsum can show various colours, ranging from white to brown, yellow, gray and pink.

To make plaster of Paris, gypsum is gently heated to drive off the water of crystallisation contained within the gypsum crystals. It would seem that the name 'gypsum' reflects this process of heating since it originates from the Greek word for calcined or "burned" mineral.

Plaster of Paris is very liquid when mixed up, being easy to tip out into the mould. But it then sets very quickly. The reaction with water gives off heat. The resulting plaster is very smooth and rather cold to the touch. This is due to the fact that gypsum has very low thermal conductivity, a property which make it a good insulator.

Large gypsum deposits at Montmartre were once a major source for plaster and from the 1700s, Paris became the capital of plaster, hence the name. All the walls of wooden houses were covered with plaster, as a protection against fire. The King of France had enforced this rule after the big London fire destroyed this city in 1666.

The fact that the ground beneath Montmartre is a warren of quarries has meant that it is often too unstable for new building and the quartier's characterful appearance has hence been preserved.

I have previously written about different forms of gypsum crystal such as the desert rose and Selenite or Satin Spar which is a long, rod-like crystal, quite soft, slightly flexible and often transparent with the appearance of fine threads passing along its length.