the year 1698 some of it penetrated through the soil, and the phenomenon was witnessed by many people, who believed it to be a miracle.  The church which was thereupon erected is still a well-known place for pilgrimage.  Paracelsus concludes his directions for its manufacture with the words:  But if this be incomprehensible to you, remember that only he who desires with his whole heart will find, and to him only who knocks vehemently shall the door be opened.’

‘I shall never try to make it,’ smiled Arthur.

’Then there was the Electrum Magicum, of which the wise made mirrors wherein they were able to see not only the events of the past and of the present, but the doings of men in daytime and at night.  They might see anything that had been written or spoken, and the person who said it, and the causes that made him say it.  But I like best the Primum Ens Melissae.  An elaborate prescription is given for its manufacture.  It was a remedy to prolong life, and not only Paracelsus, but his predecessors Galen, Arnold of Villanova, and Raymond Lulli, had laboured studiously to discover it.’

‘Will it make me eighteen again?’ cried Susie.

‘It is guaranteed to do so,’ answered Dr Porhoet gravely.  ’Lesebren, a physician to Louis XIV, gives an account of certain experiments witnessed by himself.  It appears that one of his friends prepared the remedy, and his curiosity would not let him rest until he had seen with his own eyes the effect of it.’

‘That is the true scientific attitude,’ laughed Arthur.

’He took every morning at sunrise a glass of white wine tinctured with this preparation; and after using it for fourteen days his nails began to fall out, without, however, causing him any pain.  His courage failed him at this point, and he gave the same dose to an old female servant.  She regained at least one of the characteristics of youth, much to her astonishment, for she did not know that she had been taking a medicine, and, becoming frightened, refused to continue.  The experimenter then took some grain, soaked it in the tincture, and gave it to an aged hen.  On the sixth day the bird began to lose its feathers, and kept on losing them till it was naked as a newborn babe; but before two weeks had passed other feathers grew, and these were more beautifully coloured than any that fortunate hen had possessed in her youth.  Her comb stood up, and she began again to lay eggs.’

Arthur laughed heartily.

’I confess I like that story much better than the others.  The Primum Ens Melissae at least offers a less puerile benefit than most magical secrets.’

‘Do you call the search for gold puerile?’ asked Haddo, who had been sitting for a long time in complete silence.

‘I venture to call it sordid.’

‘You are very superior.’

’Because I think the aims of mystical persons invariably gross or trivial?  To my plain mind, it is inane to raise the dead in order to hear from their phantom lips nothing but commonplaces.  And I really cannot see that the alchemist who spent his life in the attempted manufacture of gold was a more respectable object than the outside jobber of modern civilization.’