The complex equations and tortuous mathematical diagrams (only some of which I could understand) gradually homed in on one recurring image: that of two spirals, winding around each other like acrobatic snakes. At first I thought these the representation of the DNA structure, led to this belief by the numerous references to the so-called genetic properties of an image; a process the professor termed the 'photogenetic continuum'. Only slowly did it dawn on me that these were actually diagrams of the machine itself; blueprints, if you will, of the Charisma Engine.

I will freely admit I found all these ideas more than a little hard to take. The professor was claiming that the current image-retrieval technology could be augmented and vastly improved by his own invention, to produce not a copied image of the chosen person, but an exact replica; 'A reverberation in the charismatic field,' in Bringhome's own words, 'entirely indistinguishable from its material source'. As if this were not madness enough, he further went on to claim that 'the successful Charisma Engine will be a nurturing environment; by this I mean that the products of the retrieval will be sentient. They will have a life of their own.'

Shortly after this passage came the first mention of Lucinda Tonguebright. Hers was but one name in a long list of possibilities. It had however been underlined in a different pen, as though at a later date. And from that point on the notebooks were filled with speculations about her life and works. Of course, I was reminded of my own growing obsession.

During all this time of study I saw very little of the professor's daughter. The lady of the house kept to her own quarters most of the time. As for the young, silent manservant; I saw him only when I requested meals. I could ask for nothing more. And so, the first week passed.

I had now reached the section of the papers dealing with the Xikon sponsorship. The company had shown great interest in the professor's stated ideas of a 'fully enhanced replication', although nowhere in the correspondence did he mention the idea of sentience, as though realizing that such notions were strictly for private thought. Project Propagation, as it became known, was a prestigious undertaking for the university, and it was clear from his writings that Bringhome felt an immense pressure to deliver results. This may have caused him to throw all accepted scientific caution to the wind. How else to explain his decision to present a first tentative retrieval using only an untried prototype of the Charisma Engine? Lucinda Tonguebright was his chosen subject. To this demonstration were invited the board of the university, along with the directors of Xikon.

In the circumstances, it is perhaps fortunate that the resurrected image flickered into life for little more than two minutes. Two minutes in which (according to the professor's highly charged account) the half-formed Miss Tonguebright spat and howled, and verbally abused her creator; two minutes of precious life, in which she vomited blood and attempted physically to attack one of the Xikon directors. Somewhat reluctantly, the professor turned off the Charisma Engine; the image dispersed into thin, screaming air.

Even taking into account the professor's fevered view of the occasion, it seems hard to credit such things. An image that could produce saliva, could scream, could physically - physically! - attack a human being? No, I could not allow myself to believe such monstrosities. More likely the professor had exaggerated; more likely Miss Tonguebright's image had been badly reproduced. Some fault in the mechanism had caused the image to appear more alive than it could possibly have been.

But still, something out of the ordinary had taken place that day, in the university's media laboratory. Within a week Xikon had withdrawn their sponsorship, and Bringhome was given a month's notice from his position. However, so angry was he at this treatment - and the notebooks fairly explode with bile at this point - that the professor left at the first opportunity, taking all his workings with him.

Obviously of independent means, he had already set up a laboratory of his own, in this very house where I now lived and slept. Here he continued his studies alone, attempting to construct an improved version of the Charisma Engine. Only after a year of intensive work did he feel able to call up another image from the past, again that of Miss Tonguebright. Again, the retrieval failed, this time living for five seconds only. The professor now shunned all human contact. One can only imagine the passion that fuelled him during the next two years. Finally, he believed he had made the necessary adjustments, determined this time to allow the image to emerge, 'only at her own desired speed'.

Now begins the strangest part of the recorded account. On 22 August 2053 Bringhome activated the machine for what he stated would be 'one last final attempt to reach longingly into the past'. Here, for the first time, the notebooks stand empty. The next entry is dated seven days later. It begins, 'I have dragged her out of the air. At first, only a wave shimmer, at the centre of the engine. A princess of doubt.' He then starts to refer to the image in the second person. 'Slowly, so very slowly, your form has gathered, taking molecules from the realm. A thing of dust, with the faintest memory of a shape. And written then, alive in masques of dark light. My princess of the codes, how dare they disparage your appearance. My jigsaw girl, my lady of dreams!' The next entry, in a more controlled hand, states: 'The precise amount of charisma in any particular field is always a fixed, constant amount. By this I mean, in order to bring about a successful resurrection, some other, lesser body will have to relinquish its image. The system remains in balance. So be it; surely, any sacrifice is worthy of such a vision. Lucinda shall be mine alone.' And then, and given a page of its own: 'Tomorrow, she lives!' Here, the final notebook comes to an end.

With a somewhat palpitating heart, I closed the volume. I was sitting in the library where Hildegard Bringhome had first greeted me; sitting at the very desk no doubt at which her father had written this account. I could not help but remember that the professor had died in 2053, the very year of his final experiment. Had the strange undertaking - or failure thereof -somehow brought about his demise?

The room was quite dark, except for the few guttering candles I had been reading by. I had no sense of the time, and when I examined my pocket watch I was surprised to find it past midnight. The library seemed to be alive with another presence, as though the professor's writings had animated the air. Slowly then, I became aware that this feeling was no illusion. I turned around to find Miss Bringhome perched on her usual seat. I had by this time become used to her sudden appearances, but still, how could I not be unnerved?

'You have finished, I see,' she said. 'And have you formed an opinion?'

'Yes, I have.' Steeling myself, I went on: 'Miss Bringhome… I believe your father, for all his undoubted expertise, was suffering from a most profound delusion.'

The old woman was silent for a moment. Then she rang a small bell at her side, which summoned the young servant into the room. I really thought I was to be shown out of the house. Instead, she said to the servant, 'William, the kind gentleman wishes to visit the workshop.' Before I could say anything in reply, Miss Bringhome turned back to me: 'My lather's laboratory,' she said, by way of explanation. 'I will meet you there.'

From the very first moment my eye chanced upon Lucinda Tonguebright's name, I had felt myself caught in the grip of some superior force; now, following the servant down a short flight of steps, to the basement of the house, I knew that force had me completely in its thrall. The steps led to a short corridor, at the end of which the servant unlocked a heavy door. Inside, a dark cavernous room was dominated by a large cylindrical shape. Even in the darkness I had no doubt as to its nature. The apparatus was perhaps six feet tall by four feet in diameter, consisting of a broad base out of which a pair of entwined pipes rose upwards. The pipes were made of brass, or some similar metal, and were folded in such a way as to leave an opening through to the empty space at the very centre of the machine. I could not stop myself from gasping out loud: