Ishraq made a little irritated gesture. ‘But was Luca impressed with the lecture?’
‘Oh yes, he wants to go again. He wants to learn things while he is here. There is a great library inside the Doge’s Palace, and a tradition of scholarship. They have manuscripts from all over the world and a printing workshop which is making books. Not hand-painting them and copying them with a pen and ink, but printing hundreds at a time with some sort of machine.’
‘A machine to make books?’
‘Yes. It can print a page in a moment.’
‘But I suppose neither you nor I can listen to the lectures? Or go to see the books made? All this study is just for men? Though in the Arab world there are women scholars and women teachers?’
Isolde nodded her head. ‘Brother Peter says that women’s heads do not have the strength for study.’
‘Testa di cazzo,’ Ishraq said under her breath, and led the way downstairs.
They found Luca and Brother Peter in the dining room overlooking the Grand Canal. Luca had the shutter on the tall windows closed and had opened one of the laths a tiny crack so that a beam of light was shining onto the piece of glass he had taken from the chapel at Ravenna. He looked up as they came in: ‘I spoke to one of the scholars at San Marco,’ he remarked to Ishraq. ‘He says that before we even think about the rainbow we have to consider how things are seen.’
Ishraq waited.
‘He said that the Arab philosopher Al Kindi believed that we see things because rays are sent out from our eyes and then bounce off things and come back to the eye.’
‘Al Kindi?’ she repeated.
‘Have you heard of him?’
‘During my studies in Spain,’ she explained. ‘He translated Plato into Arabic.’
‘Could I read his work?’ Luca rose up from the table and put down the piece of glass.
She nodded. ‘He’s been translated into Latin, for certain.’
‘You would have to be sure it was not heretical writing,’ Brother Peter pointed out. ‘Coming as it does from the ancient Greeks who knew nothing of Christ, and through an infidel thinker.’
‘But everything has been translated from the Greek to the Arabic!’ Luca exclaimed impatiently. ‘Not into Italian, or French or English! And only now is it being translated into Latin.’
Ishraq showed him a small smug smile. ‘It’s just that the Arabs were studying the world and thinking about mathematics and philosophy when the Italians were—’ She broke off. ‘I don’t even know what they were doing,’ she said. ‘Was there even an Italy?’
‘When?’ Isolde asked, pulling out her chair and sitting at the table.
‘About 900 AD,’ Ishraq answered her.
‘There was the Byzantine empire and the Muslim occupation, there wasn’t really an Italy, I don’t think.’
Freize helped to carry the dishes down from the kitchen but once the dining room door was shut, he dropped the pretence, and sat down to table with them. Isolde, looking around the table, thought that they could very well pass as a loving happy family. The affection between the four young people was very clear, and Brother Peter was like a stern, slightly disapproving, older brother.
‘They invented Gorgonzola cheese,’ Freize announced, carving a large ham and passing out slices.
‘What?’ Luca choked on a laugh, genuinely surprised.
‘They invented Gorgonzola cheese, in the Po Valley,’ Freize said again. ‘I don’t think the Italians were studying the meaning of the rainbow in the year 960. They were making cheese.’ He turned to Luca. ‘Don’t you remember Giorgio in the monastery? Came from the Po Valley? Very proud of their history. Told us about Gorgonzola cheese. Said they’d been making it for five hundred years. Good thing too. Probably more use than rainbows.’ He served himself with two great slices of ham and sat down and buttered some bread.
‘You are a source of endless surprises,’ Luca told him.
‘Glad to help,’ Freize said smugly. ‘And I have more. You’ll be interested in this.’ Freize put down the bread, wiped his fingers on his breeches and brought the gold half noble coin out of his pocket. ‘I exchanged some of my smaller coins for this. A gold half noble from England. Isn’t this one of the coins that Milord wanted you to investigate?’
Luca held out his hand and looked at the bright coin. ‘Yes – an English half noble. It’s perfect,’ he said. ‘Not a mark on it.’
He passed it to Brother Peter who studied it and then handed it on to Isolde. ‘Why is Milord so interested in these coins?’ she asked.
Ishraq and Freize exchanged a hidden look as Isolde named the very question that was troubling them.
‘He believes that someone may have opened a gold mine and is minting them in secret,’ Brother Peter said. ‘Such a man would be avoiding tax, and avoiding the fines he should pay to the Church. Milord would want to see that the Church reclaimed those taxes. It would amount to a fortune. Or some criminal may be forging them.’
‘So do you think the coins are forged? Made to look like English nobles but made from lesser metal?’ Luca asked.
‘The money changer said they were from the English mint in Calais,’ Freize explained. ‘But he was very stern with us when I asked him about them – he warned me not to ask questions. He didn’t want anyone saying anything which might spoil the value of the coins.’
‘Is the value good?’
‘They might be overvalued, if anything,’ Freize volunteered. ‘They were rising in price as we stood there. He said he would put up his exchange rate tomorrow. Apparently everyone wants to trade in them – there were men queuing behind us. Everyone says they are solid gold, without any alloy. That’s very unusual. Most coins are a mixture of precious metal and something lighter. Or good ones are shaved and clipped. But these seem to be perfect.’
‘There’s only one way to be sure. We’ll have to test them to see how much real gold is in each coin,’ said Luca.
‘How shall we test it?’ Isolde asked. ‘We can’t ask the goldsmiths – as Freize said, they won’t welcome questions about the quality of their coins.’
Brother Peter looked slightly uncomfortable. He put his hand to the inner pocket of his jacket.
‘You’ve got orders!’ Freize said accusingly, eyeing the small scroll.
‘Milord honoured me . . .’
‘More secret orders!’ Freize exclaimed. ‘Where do we have to go now? Just when we are settled and have discovered fegato alla veneziana? When Luca is studying at the university, and is going to see Father Pietro? Just when he might find his father? Don’t say we have to leave! We haven’t completed our mission, we’ve not even started! The girls haven’t even bought their carnival clothes!’
‘Peace! Peace! We don’t have to move yet,’ Brother Peter said. ‘And if it was an order from Milord, then the fact that you have discovered a Venetian culinary speciality of liver and onions, and that the girls want new dresses, would not prevent us. This is vanity, Freize. And greed. No, Milord simply gave me instructions for our time in Venice. How we are to go to the Rialto when our ship comes in and claim our share of the cargo. How we are to sell it at a profit, a manifest of the cargo it is carrying. And here, a list of the tests we were to make on the gold coins, when we had them.’
He looked at Ishraq. ‘The instructions are in Arabic,’ he said awkwardly. ‘This is infidel learning. I thought you might read them to Brother Luca, and he would test the gold.’
Ishraq beamed at him in gleeful triumph. ‘You need my learning, Brother Peter?’
The older man gritted his teeth. ‘I do.’
‘You don’t think that translating a recipe for testing gold will strain my poor woman’s intelligence to breaking point?’
‘I hope that you will survive it.’
‘You don’t think that such knowledge should be kept to men, only to men?’
‘Not on this occasion.’
She turned to Luca. ‘Do you want me to translate the recipes for you? Will you te
st the gold?’
‘Of course,’ Luca said. ‘We can use the spare room next to mine. We will have our own goldsmith’s assay room!’
Only Freize caught the shadow that crossed Isolde’s face at the thought of the two of them working all day together in the small room.
‘And tomorrow, I will go out and exchange some more coins for gold,’ Brother Peter said. ‘We will have to test a number of coins to be sure.’
‘And the lasses can buy new gowns,’ Freize said happily. ‘And masks, and hats. And I shall look through my boxes and see if I can’t find some more coins to turn into English gold nobles. A man could make a small fortune in this town by doing nothing but buying at the right time.’
Immediately after breakfast, the following morning, Ishraq and Luca were side by side at a table in the spare room off the dining room, quiet with concentration. Luca was staring at half a dozen beautiful golden coins purchased by Brother Peter from the money changers. Ishraq had a scroll of manuscript before her. Carefully she unrolled it, weighted the top and bottom so that it could not roll up, and started to translate from the Arabic into Italian. ‘It says first you have to look, to see if it has been stamped or marked by the goldsmith or mint.’
Luca squinted at the coins, one after another. ‘Yes,’ he said. ‘They’re all marked as English nobles, minted by the English at Calais. They’re all marked in exactly the same way. Identical.’
He made a note on a piece of paper beside him, and then carefully put the paper over the coin and gently rubbed a coloured stick of sealing wax over it. The image on the coin showed through. ‘Now what?’
Ishraq tucked a lock of dark black hair behind her ear. ‘Check for discolouration, especially wear,’ she read. ‘If another metal is showing through the gold, then this is gold plate, a gold veneer laid over a cheaper metal.’
Obediently, Luca turned over every coin and looked at the beautifully bevelled edges of the whole coins. ‘They’re perfect. All of them. Same colour all the way round.’
‘Bite it,’ she said.
‘What?’
She giggled, and he glanced at her and smiled too. ‘It’s what it says here. Gold is soft, bite it, hold it in your mouth for the count of one hundred, and then look at it. If it is gold, your teeth should mark it.’
‘You bite it,’ Luca replied.
‘I’m the translator,’ she said modestly. ‘You’re the assayer. I am a mere woman. In your faith I think it is Eve that tells you to bite the apple. Clearly, the woman gives the instruction and the man bites. Besides, I’m not cracking my teeth on it. You’re the one that wants to know: you bite it.’
‘God Himself tells us your sex bit the apple first,’ Luca pointed out. ‘So we’ll both bite one,’ he decided, and handed her a half noble and kept a whole coin for himself. Solemnly, they both put the coins at the side of their mouths, bit down, held the coins, counted to one hundred and then looked at the result.
‘I’m amazed!’ she said.
‘I can see my teeth marks!’ he agreed.
‘Gold then.’
‘Write it down,’ Luca instructed her. ‘What’s the next test?’
‘We have to scratch it with an earthenware plate.’
Luca went to the door, opened it and yelled down the stairs. ‘Freize! Bring me a bowl from the kitchen!’
‘Hush!’ Freize said, labouring up the stairs. ‘Lady Isolde has half of Venice in her room above us, fitting her with gowns, creating headdresses for her and Ishraq.’
‘I need a bowl from the kitchen!’
‘Pewter?’ Freize asked, preparing to go on, up the narrow stairs to the attic.
‘No! No! Earthenware!’
‘Earthenware he says,’ Freize complained to himself. They could hear his footsteps going the long way up to the kitchen and then coming back down. ‘Earthenware, as you asked,’ he said, peering curiously into the room.
‘And now go away,’ Luca said hard-heartedly, though it was clear that Freize was aching to join in. To Ishraq he said: ‘Now what?’
‘You have to break it. We need a smashed piece of earthenware.’
Luca slammed the bowl against the edge of the table, and it shattered into a hundred pieces.
‘Oh fine, just break it!’ came Freize’s voice from behind the closed door. ‘Don’t worry about it, for a moment. Shall I fetch another for your lordship?’
‘And take a piece and scratch the gold with it,’ Ishraq translated. ‘A black scratch means the gold is not real but a gold scratch shows the metal is true.’
Luca drew the earthenware shard across the face of the gold noble. ‘It’s good,’ he said tersely. He pressed down hard and then looked again. ‘Definitely good.’
‘Now we have to saw it in half.’
He raised his eyebrows at the thought of damaging the coin. ‘I’ll saw one of the quarter nobles,’ he said. ‘I won’t touch the full noble.’
She shook her head. ‘Oh for heaven’s sake! Saw one of each: a noble and a half noble and a quarter noble. Go on, Luca. It’s not as if it’s your money. Milord is paying for all of this.’
‘You have expensive ideas,’ he complained. ‘If you had been brought up as a farmer’s son like me you would not willingly be sawing coins in half.’
She laughed at him, and he did as she requested and soon the coins lay halved on the bench before them.
‘Are they the same colour all the way through?’
Luca picked up a magnifying glass and scrutinised the coins. ‘Yes,’ he said. ‘There’s no skin on any of them, nor any trace of a different colour inside. They’re yellow all the way through, like pure gold.’
‘So now, it’s the last test: we have to weigh the coins,’ she said. ‘Weigh them very accurately.’
Luca paused. ‘All right. What weight should they be?’
‘A full noble is 108 grains,’ Ishraq said scowling at the manuscript, trying to understand the symbols. ‘It says that density is equal to mass divided by volume.’
‘Hang on a minute,’ Luca said. ‘Say that again.’
‘Density is equal to mass divided by volume,’ she repeated. ‘The test is to weigh pure gold and then weigh the test gold to find the mass. Then the second test is to put it in water and see how much the water level rises. That gives the volume.’
‘Mass,’ Luca repeated. ‘Volume.’
Ishraq thought that he looked for a moment like a troubadour when he sings a particularly beautiful song. The words, which made no sense to her, were like poetry to him. ‘Density.’
‘It says here that we are to take a piece of pure gold and then put it in a measured jug of water and see how much the water rises. Then we do the same with the same weight of our test gold. Gold which has been mixed with other lighter metals will move more water. Gold that is pure is more dense – it will displace less water.’ She broke off. ‘You know, I’m reading the words but I feel like a fool. I don’t understand what we are to do. Do you understand what is meant?’
Luca looked transported. ‘Density is equal to mass divided by volume,’ he said quietly. ‘I do see. I do see.’
He did not bother to shout for Freize but ran up to the kitchen himself and came back down with a clear glass of water. ‘We’ll have to go out to a goldsmith and buy some pure gold,’ he muttered.
‘What for?’
‘So that I know how dense pure gold is. So that I know how much the water rises. So that I can compare it with the coins.’
‘Oh! I see,’ Ishraq exclaimed, suddenly understanding. ‘I have a gold ring, that I know is pure gold.’
‘It’s hollow, it’s in the shape of a ring,’ Luca said, thinking furiously aloud. ‘Doesn’t matter. The central hole has no weight. We are weighing the gold of the ring not measuring the area. Get it.’
‘It’s Isolde’s mother’s ring,’ Ishraq explained. ‘I have carried it and her family jewels for her ever since we left home.’
‘Are you sure it is pure gold?’
S
he nodded. ‘The Lord of Lucretili would have given his lady nothing less,’ she said.
He did not even hear her, he was looking from the gold nobles to the water in the glass. Ishraq ran from the room up the stairs to the girls’ rooms and lifted her gown, to rip at the hem of her linen shift.
‘What on earth are you doing?’ Isolde asked. She was standing on a wooden chair, a dressmaker kneeling before her, hemming a gown. On one side a tirewoman was making a magnificent headdress and there were carnival masks all around the room, silks, satins and velvets thrown everywhere in a jumble of richness and colour.
‘Getting your mother’s gold ring,’ Ishraq said tersely, tearing at the strong hem stitches. ‘For Luca to weigh against the gold nobles.’
‘Still?’ Isolde said irritably. ‘You’ve been locked in all morning. And I heard you drop a plate.’
‘Smashed it,’ Ishraq said cheerfully, retrieving the ring and pulling down her dress again.
‘Make sure he doesn’t damage it,’ Isolde said disagreeably. ‘That ring is valuable.’
Ishraq said nothing but raced back to Luca. He was pacing up and down, scowling in thought, he hardly noticed her come in until she put the ring into his hand.
At once he turned and put it on the delicate spice scales that Freize had brought them from the kitchen. He added the tiny weights – the smallest was half a grain of wheat. Isolde’s mother’s ring was just over 121 grains.
‘Write it down,’ Luca ordered Ishraq. ‘The ring is pure gold, 121 and a half grains. Now. How much water does it move?’
Luca lifted it from the scale and put it into the water glass. At once the water rose within the glass. With a sharp piece of chalk Luca marked where the water level rose, and then hooked the ring out with a fork and held it over the water so that every drop fell back into the glass and the water level was the same as before.
‘You are certain this is pure gold?’ he asked quietly.
Ishraq was impressed with his concentration. ‘Certain,’ she whispered.
‘Well, the noble should be 108 grains,’ Luca said. ‘And the noble plus half of one of the quarter nobles should be exactly 121 and a half grains. So the mass is the same. If it is less dense, then it has been mixed with tin or something lighter than gold, and the water will rise higher.’ Gently, without making a splash, he dropped the full coin into the glass of water, and then dropped the sawn half of the quarter noble on top of it.
Order of Darkness Page 51