Hester, rather on her mettle as a housewife, took pride both in being able to provide dinner for a dozen men and beds for half of them at a moment’s notice, and that it was the Tradescant house and garden which was the centre of attraction.

The conversation would go far into the night, and as the levels fell in the bottles of port the speculation about everything from the functions of parts of the body, to the existence of angels, the movement of the planets in their spheres and the rise and fall of sugar sap in John’s maple tree became wilder and more imaginative. Elias Ashmole, a learned lawyer, one evening swore that he could predict to an hour’s accuracy the time of a man’s death if only midwives would have the sense to record the exact time of birth to let an astronomy chart be rigorously drawn.

‘But would you want to know?’ John asked, slurring slightly.

‘I want to know everything,’ Elias replied. ‘That is what I mean by being a man of science. I, for instance, am born beneath the planet Mercury, and you can see that I am a completely mercurial man. I’m quick and versatile.’

‘And looks like a silver slug, just like the metal!’ someone interposed under his breath.

‘But a man should separate the personal from the inquiring in his life,’ a physician remarked rather confusedly. ‘I want to know how blood flows through the veins. But I’m not going to open up my own arm to have a look at it. I am not my own experiment.’

‘Not at all!’ another man interrupted passionately. ‘Unless you are prepared to penetrate, even into your own heart, then you are not inquiring at all. It is mere diversion.’

‘Oh yes! If you want to die of the plague in an experiment to see that it is infectious!’

‘Truly, one cannot study patients from a distance,’ Dr Wharton observed. ‘When the plague was in London I …’

‘And what else have we done in the body politic but make a change and see what flows from it? Cut out the heart and see if the brain can still think?’

‘That was not an experiment! It was a decision to which we were driven. I don’t see Cromwell as a great physician of the body politic! He was clinging on while the horse bolted!’

‘But I don’t mean that,’ John said, holding to his first thought with difficulty. ‘I mean, would you always want to know the future? How would you bear it?’

‘Of course you can know it,’ Elias replied. ‘I have drawn my own chart and I can tell you, for instance, that I shall be a man of considerable fame. I cast my own predictions and they told me clearly: “I shall labour for a fortune with a wife and get it.”’

‘A rich widow?’ someone asked from further down the table.