One morning the two chums were called into Armeath's private apartment, where he was awaiting them with Monck. He explained that he had received the king's permission to impart to them an important piece of information. 'I am going to entrust you with a bit of a secret,' said he, 'and I must ask you to regard it as confidential, and say nothing about it to any one—particularly to the Zuanstrooms; which, of course, includes the two lads. Doubtless you have wondered what it was which induced King Ivanta to pay a second visit to our Earth. It is this, that what we call precious stones do not exist naturally in Mars. None were ever seen there until the king brought back a quantity after his first visit.'
Gerald burst into an exclamation. 'Just what I guessed, sir,' he cried. 'I have had that idea in my mind for some time!'
'It was a shrewd guess, lad,' Monck observed. 'The fact is, that once the Martians had set eyes on them they went almost mad over them, and became clamorous for a larger supply to be brought, in order that those who could afford it might be able to purchase some.
'Our gracious master, who is continually thinking what new thing he can do to please his people, determined to pay a second visit to the Earth specially to secure a large supply. Hence his taking up with Zuanstroom, the "Diamond King." But Zuanstroom was not easy to arrange with. When he learned the actual state of the case, he insisted, as a part of the bargain, that my master should promise to bring him over to Mars for a trip, and take him safely back. Nothing less would satisfy him.'
'I see,' said Jack. 'And I suppose his diamonds are on board too—a whole shipload of them, so to speak?'
'Exactly. The greatest load of treasure, I suppose, that has ever been carried on any ship of the air or the sea.'
'But,' said Gerald, 'the Zuanstrooms know all this. Why mustn't we speak to them about it?'
'Because, at this point, I come to my story,' Armeath said, with a half-smile. 'For years I have been experimenting, trying to manufacture precious stones artificially. At last I succeeded in getting diamonds from a certain mineral; only to find, however, that the discovery was almost valueless, because I could not get enough of the particular mineral. I found out that there was some in the island we have been living on, and that was the reason I went there to stay for a time. When, however, I understood what King Ivanta wanted, I told him of my experiments, showed him the results, and he was highly delighted. He said it would be easier and cheaper to manufacture diamonds than to buy them from the Diamond King on his own terms.'
'But how can that be done, sir, if the necessary material is so scarce?' asked practical Jack.
'You shall hear. King Ivanta recognised the mineral, and declares that there is plenty of it to be obtained from the planet Saturn. He saw quantities of it when he was there!'