Wednesday 1 August 2012

Aeolipile


Hero steps back and looks at the mechanism again. It is beautiful. The smith was able to solve his problem of the arm length and there it stands. His ball of the wind.

A golden ball sits atop the small covered cauldron suspended on two hollow supports through which the steam from the boiling water will travel. Through two arms that flow from the ball the steam would then fly, producing motion in the ball. The water is lit and he waits. He can hear the bubbling, the hissing, the fire starting to do its work. Then the first puff of steam, the first hazy expulsion. There is only one place for it to go.

The ball starts to move. Hero leaps up. ‘Gods be praised’ he yells.

‘Julia’ he cries, ‘Julia it works.’

His wife runs in from the Alexandrian summer and sees the spinning golden ball, flames licking at the cauldron.

‘Aeolus!’ she cries to the god of wind, ‘what have you done Hero? What is that?’

‘It is a toy!’ he raises his hands, ‘have no fear; it moves because I have forced the steam to flow from the cauldron to the ball and then through these two arms, and so it spins. It should amuse at our next supper? No?’

Julia walks towards the cauldron and peers at the still rotating orb.

‘Is it safe?’ She asks, picking up a poker and prodding the dying fire. The orb is slowing.

‘Of course, he says, ‘as long as the pressure of the steam has a release it will be fine’.  

‘So what does it do?’ She asks.

‘It spins’ he says, ‘it whirls.’

‘To what end my love’ she presses home the point. ‘Caesar did not go to Britain because it span, or looked pretty, why is it there?’

‘It is a distraction’ hero laughs, that is all. He walks away, he shakes his head at his wifes silliness, what use would it be. He picks a pomegranate from the carved wooden bowl  on the table and walks out into the sunshine she has abandoned.

Julia reaches out to the golden orb, it is still hot to her touch, she moves it gently with the end of a fingernail, it swings in it’s cradle.

She has been spinning this morning. The triremes carrying Roman wool have provided a great deal to do. The spinning orb reminds her of the spinning wheel. How long would it take an orb to spin the wool she wonders.

Just how much time would she save.

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