It was better, he reasoned to himself, simply to make an excuse, even though he already knew that that would require him to sit through another lecture.
‘I won’t bother you with the details, Ali, but I have to go away unexpectedly, and I want to take the relic with me when I leave. That’s why I’m in such a hurry.’
A tall and excessively thin Arab, his face burned almost black by the sun and wearing a white thawb, the long tunic that is the traditional dress for Arab men, approached their table, a grubby white cloth held in his left hand. Husani and Mohammed both ordered coffee and glasses of water, Mohammed a small selection of sweet cakes, and the waiter retreated.
‘So what have you found?’
‘First, I need to explain a little about the parchment itself,’ Mohammed said.
Husani stifled his impatience. Although he knew that time was crucial, he also needed to hear everything that the scientist could tell him about the relic.
‘You probably noticed,’ Mohammed began, ‘that the parchment is dark brown in colour. That’s an indication of its age, because when it’s freshly prepared parchment is almost pure white. Unfortunately, simply looking at the colour does not enable a researcher to estimate the likely age of the object, because the speed of the colour change depends upon the conditions in which the parchment has been kept. The temperature, the humidity, amount of sunlight and so on. It will last longest if it is stored in a dark and very dry place and at a fairly constant temperature, although the temperature is not as important as the relative humidity.
‘The colour change of the parchment is one factor, and the ink is the second. Although the writing on the object now looks brownish in colour, originally it would have been a deep black, and very easy to read against the white parchment. Because the writing is obviously Latin, it’s reasonable to assume that the text was written by a Roman or perhaps by a scribe employed by the Romans, and so the ink used would most probably have been a form of atramentum.’
Mohammed raised his hand to forestall Husani’s obvious question.
‘That isn’t actually any one particular type of substance,’ he said. ‘The Latin word simply means a black-coloured medium, so in Roman times an atramentum could be produced from cuttlefish ink, for example, or soot from a chimney or charcoal from a fire, the pigment then being mixed with water. Using soot or charcoal gave rise to a type of ink known as carbon black, for obvious reasons. Different sorts of atramentum could be used for other purposes, not just writing, such as dyeing leather or in painting, but the type used for writing became known as atramentum librarium.’
‘Presumably that was the origin of the English word “library”?’ Husani asked, pleased to have some faintly intelligent comment, however oblique, to add to the discussion.
‘Yes, though indirectly. In Latin, librarium came to mean a “chest of books or scrolls”, and the word was then absorbed into Old French in about the fourteenth century as librairie, meaning a “collection of books”.’
‘So is the type of ink important?’ Husani asked, eager to get the explanation back on track.
Mohammed nodded decisively.
‘Yes, because of how you should then treat the parchment or material. A later type of ink was known as iron gall ink, which was made from entirely different materials, and because the two inks have very different characteristics and origins it’s important to establish which type has been used, so that the correct conservation methods can be employed. I’m quite sure that in the case of this piece of parchment, because of its age and because of the use of Latin on it, that the writing was done with a form of atramentum, an ink made from some type of carbon.
‘The other good thing about this parchment is that it looks as if it was only used once, which is actually slightly unusual. Preparing parchment from the skin of an animal, usually a sheep or a goat, was quite a long and complicated process, and it was very common in ancient times for a parchment to be used multiple times. When this was done, the parchment was known as a palimpsest.’
‘How did they rub out the original writing?’ Husani asked.
‘The method used is actually hinted at by the name, because it’s derived from two Greek words which mean “scraped again”. The parchment would be rubbed smooth to remove as much of the old ink as possible, and to prepare the surface to be written on again. And although this process appears to completely erase the original writing, at least to the naked eye, traces of it usually remain and can be seen when the relic is examined in a laboratory. The original letters can serve to partially obliterate the later writing.’
‘You mean that one set of words that you can’t read can obscure another set that you also possibly can’t read?’
Mohammed nodded.
‘That’s a somewhat crude way of putting it, but it’s a reasonably accurate statement. But in the case of your parchment, that’s not a problem. The difficulty with this relic is much simpler. It’s a matter of trying to decipher the faded and dark brown letters that have been written on a piece of parchment that has now aged to virtually the same colour.
‘Fortunately, we have a couple of tools that can help us in our quest. We’ve known for a long time that shining an ultraviolet light on the parchment and then photographing it with a high-resolution camera can reveal erased or hidden letters. The ultraviolet light makes the parchment fluoresce — it actually emits a bluish light — and that contrast enables us to make out the words. And particularly with inks derived from some form of carbon, we’ve found that photographing the relic using infrared light can also work well.’
‘And so that’s what you did?’ Husani asked, feeling some relief that the lecture appeared to be approaching its conclusion.
‘That is indeed what I did,’ Mohammed confirmed. ‘I used both techniques, in fact, and both produced positive results. I won’t get them out of the briefcase to show you, because the parchment is delicate and shouldn’t be exposed to bright sunlight. And you really need to study the photographs using a magnifying glass to be able to decipher the text. I haven’t tried to read it myself — I had only just completed taking the photographs when you rang, and I only had time to print copies of them before coming out to meet you — but quite clearly more of the words are visible in the pictures than we could see on the parchment itself, though by no means all of them. Hopefully you’ll be able to decipher enough of it to work out what the text is describing.’
Husani nodded his thanks and slid an envelope containing a number of banknotes across the table to the scientist.
‘Thanks a lot, Ali,’ he said. ‘Can I take the briefcase as well?’
Mohammed nodded.
‘I expected that you would want to do that, so I brought one of my old ones.’
Husani took the briefcase from his companion and placed it on his lap. Then he made a decision, leaned forward and gestured for Mohammed to do the same.
‘I suggest,’ he said, in a quiet but forceful voice, ‘that you forget all about me and this parchment. You may have heard about the murder of a market trader here in Cairo, a man named Mahmoud Kassim.’
Mohammed nodded again. It seemed as if Husani had actually been one of the last people in the city to learn about the man’s death.
‘I bought the parchment from him, and I think it’s most likely that he was tortured to make him reveal where it was. The man I believe killed him broke into my house less than an hour ago, and I only just managed to get away from him. That’s why I’m leaving Cairo today, as soon as I can, and that’s why you shouldn’t tell a living soul that you’ve even seen the relic, and certainly don’t admit to anyone that you did any work on it.’