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.