It is very fortunate, too, that I have been supplied with all the writing materials I require, for during my long hours of idleness I have been able to jot down in my notebook the slightest incidents that have occurred since I was abducted from Healthful House, and to keep a diary day by day.  As long as I am permitted to use a pen I shall continue my notes.  Mayhap some day, they will help to clear up the mysteries of Back Cup.

From July 5 to July 25.—­A fortnight has passed, and all my attempts to get near Thomas Roch have been frustrated.  Orders have evidently been given to keep him away from my influence, inefficacious though the latter has hitherto been.  My only hope is that the Count d’Artigas, Engineer Serko, and Captain Spade will waste their time trying to get at the inventor’s secrets.

Three or four times to my knowledge, at least, Thomas Roch and Engineer Serko have walked together around the lagoon.  As far as I have been able to judge, the former listened with some attention to what the other was saying to him.  Serko has conducted him over the whole cavern, shown him the electric power house and the mechanism of the tug.  Thomas Roch’s mental condition has visibly improved since his departure from Healthful House.

Thomas Roch lives in a private room in Ker Karraje’s “mansion.”  I have no doubt that he is daily sounded in regard to his discoveries, especially by Engineer Serko.  Will he be able to resist the temptation if they offer him the exorbitant price that he demands?  Has he any idea of the value of money?  These wretches may dazzle him with the gold that they have accumulated by years of rapine.  In the present state of his mind may he not be induced to disclose the composition of his fulgurator?  They would then only have to fetch the necessary substances and Thomas Roch would have plenty of time in Back Cup to devote to his chemical combinations.  As to the war-engines themselves nothing would be easier than to have them made in sections in different parts of the American continent.  My hair stands on end when I think what they could and would do with them if once they gained possession of them.

These intolerable apprehensions no longer leave me a minute’s peace; they are wearing me out and my health is suffering in consequence.  Although the air in the interior of Back Cup is pure, I become subject to attacks of suffocation, and I feel as though my prison walls were falling upon me and crushing me under their weight.  I am, besides, oppressed by the feeling that I am cut off from the world, as effectually as though I were no longer upon our planet,—­for I know nothing of what is going on outside.

Ah! if it were only possible to escape through that submarine tunnel, or through the hole in the dome and slide to the base of the mountain!

On the morning of the 25th I at last encounter Thomas Roch.  He is alone on the other side of the lagoon, and I wonder, inasmuch as I have not seen them since the previous day, whether Ker Karraje, Engineer Serko, and Captain Spade have not gone off on some expedition.