He looked round, beaming on the assembly.

'Now, there is my little problem. I have, I hope, stated it clearly. I should be interested to hear your views.'

To everyone's astonishment Miss Marple gave vent to a long and prolonged chuckle. Something seemed to be amusing her immensely.

'What is the matter, Aunt Jane? Can't we share the joke?' said Raymond.

'Mr. Petherick's story is a catch. So like a lawyer! Ah, my dear old friend!' She shook a reproving head at him.

'I wonder if you really know,' said the lawyer with a twinkle.

Miss Marple wrote a few words on a piece of paper, folded them up and passed them across to him.

Mr. Petherick unfolded the paper, read what was written on it and looked across at her appreciatively.

'My dear friend,' he said, 'is there anything you do not know?'

'I knew that as a child,' said Miss Marple. 'Played with it too. '

' I feel rather out of this, ' said Sir Henry. 'I feel sure that Mr. Petherick has some clever legal legerdemain up his sleeve. '

'Not at all,' said Mr. Petherick. 'Not at all. It is a perfectly fair straightforward proposition. You must not pay any attention to Miss Marple. She has her own way of looking at things.'

The lawyer shook his head.

'I will go on where I left off. I was dumbfounded and quite as much at sea as all of you are. I don't think I should ever have guessed the truth probably not - but I was enlightened. It was cleverly done too.

'I went and dined with Philip Garrod about a month later, and in the course of our after dinner conversation, he mentioned an interesting case that had recently come to his notice.

'I should like to tell you about it, Petherick, in confidence, of course.'

'Quite so,' I replied.

'A friend of mine who had expectations from one of his relatives was greatly distressed to find that that relative had thoughts of benefiting a totally unworthy person. My friend, I am afraid, is a trifle unscrupulous in his methods. There was a maid in the house who was greatly devoted to the interests of what I may call the legitimate party. My friend gave her very simple instructions. He gave her a fountain pen, duly filled. She was to place this in a drawer in the writing-table in her master's room, but not the usual drawer where the pen was generally kept. If her master asked her to witness his signature to any document and asked her to bring him his pen, she was to bring him not the right one, but this one which was an exact duplicate of it. That was all she had to do. He gave her no other information. She was a devoted creature and she carried out his instructions faithfully.'

'He broke off and said, 'I hope I am not boring you, Petherick.'

'Not at all,' I said. 'I am keenly interested.' Our eyes met.

'My friend is, of course, not known to you,' he said.

'Of course not,' I replied.

'Then that is all right,' said Philip Garrod.

'He paused then said smilingly, 'You see the point? The pen was filled with what is commonly known as Evanescent Ink - a solution of starch in water to which a few drops of iodine has been added. This makes a deep blue-black fluid, but the writing disappears entirely in four or five days.'

Miss Marple chuckled.

'Disappearing ink,' she said. 'I know it. Many is the time I have played with it as a child.'

And she beamed round on them all, pausing to shake a finger once more at Mr. Petherick.

'But all the same it's a catch, Mr. Petherick, ' she said. 'Just like a lawyer.'

The Thumb Mark of St Peter

'And now, Aunt Jane, it is up to you,' said Raymond West

'Yes, Aunt Jane, we are expecting something really spicy,' chimed in Joyce Lumpier.

'Now, you are laughing at me, my dears,' said Miss Marple placidly. 'You think that because I have lived in this out-of-the-way spot all my life I am not likely to have had any very interesting experiences.'

'God forbid that I should ever regard village life as peaceful and uneventful,' said Raymond with fervour. 'Not after the horrible revelations we have heard from you! The cosmopolitan world seems a mild and peaceful place compared with St Mary Mead.'

'Well, my dear,' said Miss Marple, 'human nature is much the same everywhere, and, of course, one has opportunities of observing it at close quarters in a village.'

'You really are unique. Aunt Jane,' cried Joyce. 'I hope you don't mind me calling you Aunt Jane?' she added. 'I don't know why I do it.'

'Don't you, my dear?' said Miss Marple.

She looked up for a moment or two with something quizzical in her glance, which made the blood flame to the girl's cheeks. Raymond West fidgeted and cleared his throat in a somewhat embarrassed manner.

Miss Marple looked at them both and smiled again, and bent her attention once more to her knitting.

'It is true, of course, that I have lived what is called a very uneventful life, but I have had a lot of experience in solving different little problems that have arisen. Some of them have been really quite ingenious, but it would be no good telling them to you, because they are about such unimportant things that you would not be interested - just things like: Who cut the meshes of Mrs Jones's string bag? and why Mrs Sims only wore her new fur coat once. Very interesting things, really, to any student of human nature. No, the only experience I can remember that would be of interest to you is the one about my poor niece Mabel's husband.

'It is about ten or fifteen years ago now, and happily it is all over and done with, and everyone has forgotten about it. People's memories are very short - a lucky thing, I always think.'

Miss Marple paused and murmured to herself:

'I must just count this row. The decreasing is a little awkward. One, two, three, four, five, and then three purl; that is right. Now, what was I saying? Oh, yes, about poor Mabel.

'Mabel was my niece. A nice girl, really a very nice girl, but just a trifle what one might call silly. Rather fond of being melodramatic and of saying a great deal more than she meant whenever she was upset She married a Mr Denman when she was twenty-two, and I am afraid it was not a very happy marriage. I had hoped very much that the attachment would not come to anything, for Mr Denman was a man of very violent temper - not the kind of man who would be patient with Mabel's foibles - and I also learned that there was insanity in his family. However, girls were just as obstinate then as they are now, and as they always will be. And Mabel married him.

'I didn't see very much of her after her marriage. She came to stay with me once or twice, and they asked me there several times, but, as a matter of fact, I am not very fond of staying in other people's houses, and I always managed to make some excuse. They had been married ten years when Mr Denman died suddenly. There were no children, and he left all his money to Mabel. I wrote, of course, and offered to come to Mabel if she wanted me; but she wrote back a very sensible letter, and I gathered that she was not altogether overwhelmed by grief. I thought that was only natural, because I knew they had not been getting on together for some rime. It was not until about three months afterwards that I got a most hysterical letter from Mabel, begging me to come to her, and saying that things were going from bad to worse, and she couldn't stand it much longer.

'So, of course,' continued Miss Marple, 'I put Clara on board wages and sent the plate and the King Charles tankard to the bank, and I went off at once. I found Mabel in a very nervous state. The house, Myrtle Dene, was a fairly large one, very comfortably furnished. There was a cook and a house-parlourmaid as well as a nurse-attendant to look after old Mr Denman, Mabel's husband's father, who was what is called "not quite right in the head". Quite peaceful and well behaved, but distinctly odd at times. As I say, there was insanity in the family.